CN100343721C

Movatterモバイル変換

Info

Publication number: CN100343721C
Application number: CNB031523897A
Authority: CN
Inventors: 关根淳; 服部徹夫
Original assignee: Nikon Corp
Current assignee: Nikon Corp
Priority date: 2002-09-27
Filing date: 2003-07-31
Publication date: 2007-10-17
Anticipated expiration: 2023-07-31
Also published as: CN1485648A

Abstract

In a projection display apparatus that analyzes to pick up lights emitted from a plurality of the reflective light valves, color-composes the analyzed lights and projects the color-composed light, a dichroic film is disposed in at least one of optical paths of the respective color lights between the polarizing beam splitters and the dichroic prism. The dichroic film reflects such a component of a color light derived from the composite light incident on the projection optical system that has been reflected by a surface of a lens element constituting the projection optical system and incident on the dichroic prism after passing through a quarter wave phase plate and reflected or transmitted by the dichroic film within the dichroic prism to travel along the optical path of the color light in the reverse direction, thereby deflecting the color light component out of the optical path.

Description

Projection display apparatus

The application requires to enjoy the right of priority of Japanese patent application JP2002-126562 and JP2002-282204, and this application is drawn at this and is reference.

Technical field

The present invention relates to a kind of projection display apparatus, it decomposes the synthetic light that decomposes of light, color that reception is sent from a plurality of reflective light valves, and by projection optical system projection complex light (or the synthetic light of color).The invention particularly relates to a kind of method that is used for avoiding producing the ghost image in projected light.

Background technology

Be described below with reference to the projection display apparatus of the apparatus sketch shown in Figure 14 routine.

The source beam that sends from thelight source 101 of lamp and recessed catoptron composition comprises the random polarization that luminous flux is substantially parallel.Source beam incides on thepolarization converter 102, thereby converts the S polarized light of electric vector orientation of oscillation (below be called the polarization direction) perpendicular to the accompanying drawing paper to.Quadraturedichroic mirror 103 is further walked and entered to light beam, in this quadrature dichroic mirror, have thedichroic mirror 103B of reflection B (promptly blue) light characteristic and have the orthogonal distribution of dichroic mirror 103RG of reflection R (promptly red) and G (promptly green) light characteristic, thereby form an X-shaped.The light that incides on thedichroic mirror 103 is resolved into B light and the complex light that comprises R light and G light by color, and their opposite toward each other directions are propagated.

The B light that color is decomposed thus is deflectedmirror 104 reflection, thereby has changed its direction of propagation and incide on thepolarization beam apparatus 107B that is provided with into B light.On the other hand, the complex light that comprises R light and G light separately is deflectedmirror 105 reflections, thereby changed its direction of propagation, entereddichroic mirror 106 with reflection G light characteristic, color resolve into be reflected in case further the G light of propagating and by transmission so that the further R light of propagating.R light that separates thus and G light incide and are respectivelypolarization beam apparatus 107R and thepolarization beam apparatus 107G that shades of colour is provided with.

Because all versicolor light that incide on the versicolor polarization beam apparatus all are the S polarized lights, so they are substantially perpendicular to the polarization beam splitting face reflection that the accompanying drawing paper distributes among Figure 14, thereby further propagate and enter respectivelyreflective light valves 108B,reflective light valves 108R and thereflective light valves 108G that is provided with into shades of colour.

Inciding shades of colour light on the versicolor light valve is subjected to the modulation of color signal and is reflected into from its outgoing.Then, these light incide on the versicolor polarization beam apparatus again, the light modulated (P polarized light) that sees through the polarization beam splitting face reception that is decomposed.Non-modulation light (for the S polarized light) is polarized beam splitter reflection and is propagating on the direction of light source.

In versicolor decomposition light, B light and R light pass half-wavelength phase-

plate

109 and 110 respectively, thereby be converted into the S polarized light and enterquadrature dichroic prism 111, and this quadrature dichroic prism constitutes a color combining optical from the different relative planes of incidence.The G light that decomposes incides on the dichroic prism with the state that the P polarization state does not become.

Thequadrature dichroic prism 111 that constitutes color combining optical is composite prisms, has thedichroic film 111R of reflection R light characteristic and has the orthogonal distribution of dichroic film B of reflecting the B light characteristic, forms an X shape.The B light that incides on thisprism 111 is reflected by B light reflectiondichroic film 111B, the R light that incides on theprism 111 is reflected by R light reflectiondichroic film 111R, and the G light that incides on theprism 111 is reflecteddichroic film 111R transmission by B light reflectiondichroic film 111B and R light.Therefore it is compound or color synthetic to reach color, and complex light is from 111 outgoing of quadrature dichroic prism.

To make R light and B light before incidingquadrature dichroic prism 111 be the S polarized light, make G light is the loss that the reason of P polarized light is to reduce by the optical characteristics of utilizing

dichroic film

111R and 111B the incident light light quantity, favourable to complex light, thus the brightness of projection image strengthened.

Pass quarter-wave phase-plate 112 from the RGB complex light that quadraturedichroic prism 111 sends, thereby light is transformed into circularly polarized light.Light incides projectionoptical system 113 and projects to (not shown) on the screen then.

Be projected into the purpose of ghost image for fear of the light of the reflection from lens that is configured projection optical system, between quadraturedichroic prism 111 and projectionoptical system 113, quarter-wave phase-plate 112 is set, as described in Japanese patent application JP9-251150, this patent is had by the application's assignee.Specifically, incide the light that the part of the surface reflection of a plurality of lens elements that are configured projection optical system on the projectionoptical system 113 is projected and turn back to quarter-wave phase-plate and therefrom transmission.Therefore, R light component and B light component are transformed into the P polarized light from circularly polarized light in the light that returns, and the G light component is transformed into the S polarized light from circularly polarized light.The light that incidesquadrature dichroic prism 111 is resolved into various polarized lights and incides versicolor polarization beam apparatus by this prism color, and wherein G light keeps its S polarization state, and R light and B light are transformed into the S polarized light by half-wavelength phase-plate 110 and 109.Inciding polarized light on the versicolor polarization beam apparatus is polarized the beam-splitting surface reflection and propagates along optical axis.

Referring to Japanese patent application JP2000-330196, this application file discloses a kind of projection display apparatus of the above-mentioned type at this.

But we find, in aforesaid conventional projection display apparatus, even a quarter-wave phase-plate that is used to prevent projection ghost image is set, but still can produce the ghost image between dichroic prism and projection optical system.

Summary of the invention

The objective of the invention is to prevent to produce aforesaid ghost image.

The projection display apparatus that can achieve the above object according to the present invention comprises:

Be respectively the reflective light valves that the light of the light of first kind of color and second kind of color is provided with;

Be the polarization beam apparatus that shades of colour light is provided with, decompose and receive modulated and from the shades of colour light of described each reflective light valves outgoing;

A dichroic prism, respectively from the different decomposition light that incident is sent from the described polarization beam apparatus of shades of colour light on it, described dichroic prism has a dichroic film with characteristic of the light that reflects first kind of color, wherein the light of first kind of color is reflected by described dichroic film, the light of second kind of color is by the transmission of described dichroic film, make that the light of the light of described first kind of color and described second kind of color is compound by color, and complex light is from the dichroic prism outgoing;

A quarter-wave phase-plate is transformed into circularly polarized light to described complex light;

A projection optical system, the described complex light that has been transformed into circularly polarized light of projection;

A dichroic film, be arranged on wherein at least one light path of the polarization beam splitting face of described shades of colour optical polarization beam splitter and the shades of colour light between the described dichroic prism, reflect the light component of second kind of color telling the described complex light on inciding described projection optical system, this light component is configured a surface reflection of the lens element of described projection optical system, and after passing described quarter-wave phase-plate, incide on the dichroic prism, reflected to propagate in the other direction by the dichroic film in the described dichroic prism again along the light path of first color of light; Perhaps reflect the light component of first kind of color telling the described complex light on inciding described projection optical system, this light component be configured described projection optical system lens element a surface reflection and after passing described quarter-wave phase-plate, incide on the described dichroic prism, again by the dichroic film transmission in the described dichroic prism propagating in the other direction along the light path of second color of light, thereby the light component of described second kind of color or the light component deflection of first kind of color are gone out the light path of described first kind of color of light or the light path of second kind of color of light.

In projection display apparatus according to the present invention, being polarized beam splitter, to incide the electric vector orientation of oscillation of light of the light of first kind of color on the dichroic prism and second kind of color after decomposing preferably orthogonal.

In addition, in projection display apparatus according to the present invention, be arranged between the polarization beam splitting face of described shades of colour polarisation of light beam splitter and the described dichroic prism dichroic film at least one light path in the shades of colour light light path and be arranged in the light path between described polarization beam apparatus and the described dichroic prism.

In addition, in projection display apparatus according to the present invention, between the polarization beam splitting face that is arranged on described shades of colour polarisation of light beam splitter and the described dichroic prism in the shades of colour light light path dichroic film at least one light path preferably be arranged within the described polarization beam apparatus in the mode relative with described polarization beam splitting face.

Projection display apparatus according to a further aspect of the invention comprises:

Be respectively the reflective light valves that ruddiness, green glow and blue light are provided with;

Be the polarization beam apparatus that shades of colour light is provided with, decompose and receive modulated and from the shades of colour light of described reflective light valves outgoing of all kinds;

A quadrature dichroic prism, the decomposition light that sends from the shades of colour optical polarization beam splitter is respectively from different face incident on it, described quadrature dichroic prism has one to have the reflection to red light dichroic film of reflect red characteristic and the blu-ray reflection dichroic film that has the reflect blue characteristic, two films are orthogonal, wherein ruddiness is reflected by described reflection to red light dichroic film, blue light is reflected by described blu-ray reflection dichroic film, green glow is by described reflection to red light dichroic film and the transmission of described blu-ray reflection dichroic film, make the light of these colors be synthesized, and complex light is from the outgoing of quadrature dichroic prism by color;

Wherein, sending and incide ruddiness on the described quadrature dichroic prism and blue light from described shades of colour polarisation of light beam splitter is the S polarization with respect to the reflection to red light dichroic film and the blu-ray reflection dichroic film of described quadrature dichroic prism, is the P polarization from described polarization beam apparatus outgoing and the green glow that incides on the described quadrature dichroic prism with respect to described reflection to red light dichroic film and described blu-ray reflection dichroic film; With

Described equipment also comprises a dichroic film, be arranged on the polarization beam splitting face of described shades of colour optical polarization beam splitter and the shades of colour light light path between the described quadrature dichroic prism at least one in, reflect the ruddiness told the complex light on inciding described projection optical system or the component of blue light, this light component is configured a surface reflection of the lens element of described projection optical system, after passing described quarter-wave phase-plate, incide on the described quadrature dichroic prism, and incide on described reflection to red light dichroic film and the described blu-ray reflection dichroic film, propagated in the other direction with light path by described reflection to red light dichroic film and the transmission of described blu-ray reflection dichroic film again along green glow; Perhaps reflect the green component of telling the complex light on inciding described projection optical system, green component be configured described projection optical system lens element a surface reflection and after passing described quarter-wave phase-plate, incide on the described quadrature dichroic prism, again by at least one reflection in described two dichroic films propagating in the other direction along the light path of described ruddiness or blue light, thereby described red light component, blue light components or green component deflection are gone out light path.

In projection display apparatus according to a further aspect of the invention, be arranged between the polarization beam splitting face of described shades of colour polarisation of light beam splitter and the described quadrature dichroic prism dichroic film at least one light path in the shades of colour light light path and be preferably disposed in the light path between described polarization beam apparatus and the described quadrature dichroic prism.

In addition, in projection display apparatus according to a further aspect of the invention, between the polarization beam splitting face that is arranged on described shades of colour polarisation of light beam splitter and the described quadrature dichroic prism in the shades of colour light light path dichroic film at least one light path preferably be arranged within the described polarization beam apparatus in the mode relative with described polarization beam splitting face.

Projection display apparatus according to third aspect present invention comprises:

Reflective light valves for the ruddiness setting;

A polarization beam apparatus decompose to receive modulated and from the light of described reflection to red light light valve outgoing;

A dichroic prism, the decomposition light incident of sending from described polarization beam apparatus is on it, described dichroic prism has a reflection to red light dichroic film with reflect red characteristic, and wherein ruddiness is by described reflection to red light dichroic film reflection and from the dichroic prism outgoing;

A quarter-wave phase-plate is transformed into circularly polarized light to the light from described dichroic prism outgoing;

A projection optical system, the described light that has been transformed into circularly polarized light of projection;

Wherein the ruddiness that sends and incide on the described dichroic prism from described polarization beam apparatus is the S polarization with respect to described reflection to red light dichroic film; With

Described reflection to red light dichroic film has a reflection/transmission boundary wavelength for the P polarized light at the boundary of ruddiness and green glow, and described P polarized light has an orientation of oscillation with the orientation of oscillation quadrature of described S polarized light.

Description of drawings

Fig. 1 is the sketch of the projection display apparatus of first embodiment of the invention;

Fig. 2 is the major part skeleton view of the projection display apparatus of first embodiment of the invention;

Fig. 3 A and 3B are respectively the optical indicatrixs as two dichroic films in the quadrature dichroic prism of color combining optical in the projection display apparatus of first embodiment of the invention;

Fig. 4 A, 4B and 4C are the optical indicatrixs that is used in the dichroic mirror in the projection display apparatus of the present invention first to fourth embodiment;

Fig. 5 A and 5B are respectively the optical indicatrixs as two dichroic films in the quadrature dichroic prism of color synthesis system in the projection display apparatus of second embodiment of the invention;

Fig. 6 A and 6B are respectively the optical indicatrixs as two dichroic films in the quadrature dichroic prism of color synthesis system in the projection display apparatus of second embodiment of the invention;

Fig. 7 is the sketch of the projection display apparatus of fourth embodiment of the invention;

Fig. 8 is the polarization beam apparatus sketch that is used in the projection display apparatus of fourth embodiment of the invention;

Fig. 9 is the projection display apparatus sketch of fifth embodiment of the invention;

Figure 10 is the optical indicatrix as a dichroic film in the dichroic prism of color synthesis system in the projection display apparatus of fifth embodiment of the invention;

Figure 11 is the optical indicatrix as another dichroic film in the dichroic prism of color synthesis system in the projection display apparatus of fifth embodiment of the invention;

Figure 12 is the optical indicatrix as the dichroic mirror in the projection display apparatus of fifth embodiment of the invention;

Figure 13 is the optical indicatrix as another dichroic mirror in the projection display apparatus of fifth embodiment of the invention;

Figure 14 is the sketch of the projection display apparatus of routine;

Figure 15 is the sketch how projection display apparatus that is used for interpretation routine produces terrible light beam.

Embodiment

[to the research of terrible light beam cause]

In as relevant background technology part, described the Investigational conventional projection display apparatus of the inventor, and found the cause of terrible light beam, described below.

At first, referring to Figure 15 the terrible image that how to produce R light is described.Light source, polarization converter and part color separation optical system that earlier in respect of figures 14 is described in Figure 15, have been omitted, dichroic mirror 106, versicolor polarization beam apparatus 107R, 107G and the 107B of reflection G light have only been expressed, versicolor light valve 108R, 108G and 108B, half-wavelength phase-plate 109 and 110, color combining optical 111, quarter-wave phase-plate 112 and a projection optical system 113.The light modulated (that is, the P polarized light) that is included in the R light of outgoing from R light light valve 108R incides on the polarization beam apparatus 107R, by its polarization beam splitting face transmission, and sends from polarization beam apparatus 107R.This light beam is changed into the S polarized light by half-wavelength phase-plate 110 and incides on the quadrature dichroic prism 111 then.The S polarized light that incides on the quadrature dichroic prism sends by the 111R reflection of the R light in quadrature dichroic prism reflection dichroic film and from it, is transformed into a branch of circularly polarized light by quarter-wave phase-plate 112 and incides on the projection optical system 113.Incide that the part of surface reflection that R light on the projection optical system is configured the lens element of projection optical system turns back to quarter-wave phase-plate 112 and by its transmission, reflected light is transformed into the P polarized light thus.This light beam incides again on the dichroic prism 111 then.

Fig. 3 A and 3B represent the polarization direction of quadrature dichroic prism and the dependence of reflection characteristic.Fig. 3 A represents the reflection characteristic of R light reflection dichroic film 111R, and Fig. 3 B represents the reflection characteristic of B light reflection dichroic film 111B.Reflection characteristic is inevitable to be changed according to polarization direction (that is still being the S polarization according to polarization for the P polarization).More particularly, in the reflection characteristic of the reflection of the R light shown in Fig. 3 A dichroic film 111R, by the R reflection of light/TRANSMITTING BOUNDARY IN FREQUENCY wavelength X of R light reflection dichroic film 111R as the reflection of S polarized light_RSWith the R reflection of light/TRANSMITTING BOUNDARY IN FREQUENCY wavelength X that is reflected as the P polarized light by R light reflection dichroic film 111R_RpDiffer from one another, and the boundary wavelength of S polarized light is shorter than the boundary wavelength of P polarized light.As previously mentioned, once the lenticular element surfaces that is projected optical system as S polarized light reflection R light once by R light reflection dichroic film 111R was according to above-mentioned travel path reflection with return, and incided on the quadrature dichroic prism 111 as the P polarized light again.Therefore, these wavelength are less than the reflection/transmission boundary wavelength λ of P polarized light_RPLight component in fact by R light reflection dichroic film 111R transmission.The light that sees through thus enters G polarisation of light beam splitter 107G with constant P polarization state.In addition, be not re-used as the P polarized light and enter quadrature dichroic prism 111, and reflected dichroic film 111B transmission with further propagation, make it be projected into terrible light beam by R light reflection dichroic film 111R and B light by the light component of G light light valve 108G modulation.In Figure 15, dot the travel path that sends and finally become the light of terrible light beam from light valve 108.

Next describe by B light and produce the ghost image.The light modulated (that is, the P polarized light) that is included in the B light of outgoing from B light light valve 108B incides on the polarization beam apparatus 107B, by its polarization beam splitting face transmission, and sends from polarization beam apparatus.This light beam is changed into the S polarized light by half-wavelength phase-plate 109 and incides on the quadrature dichroic prism 111 then.Incide S polarized light on the quadrature dichroic prism by the 111B reflection of the B light in quadrature dichroic prism reflection dichroic film and from it, be transformed into a branch of circularly polarized light by quarter-wave phase-plate 112 and incide on the projection optical system 113.Incide that the part of surface reflection that B light on the projection optical system is configured the lens element of projection optical system turns back to quarter-wave phase-plate 112 and by its transmission, reflection B light is transformed into the P polarized light thus.This light beam incides again on the dichroic prism 111 then.In the reflection characteristic of the reflection of the B light shown in Fig. 3 B dichroic film 111B, by the B reflection of light/TRANSMITTING BOUNDARY IN FREQUENCY wavelength X of B light reflection dichroic film 111B as the reflection of S polarized light_BSWith the B reflection of light/TRANSMITTING BOUNDARY IN FREQUENCY wavelength X that is reflected as the P polarized light by B light reflection dichroic film 111B_BPDiffer from one another, and the boundary wavelength of P polarized light is shorter than the boundary wavelength of S polarized light.

As previously mentioned, once be projected the optical system reflection as S polarized light reflection B light once and returned, and incided on the quadraturedichroic prism 111 as the P polarized light according to propagation path again by B light reflection dichroic film 111B.Therefore, these wavelength are greater than the reflection/transmission boundary wavelength λ of P polarized light shown in Fig. 3 B_BPLight component in fact by B light reflectiondichroic film 111B transmission.The light that sees through thus enters G polarisation oflight beam splitter 107G with constant P polarization state.In addition, be not re-used as the P polarized light and enter quadraturedichroic prism 111, and reflecteddichroic film 111B transmission with further propagation, make it finally be projected into terrible light beam by R light reflectiondichroic film 111R and B light by the light component of G lightlight valve 108G modulation.

In addition, the inventor finds that G light also can become terrible light beam.The light modulated (that is, the P polarized light) that is included in the G light of outgoing from G lightlight valve 108G incides on thepolarization beam apparatus 107G, by its polarization beam splitting face transmission, sends and incides on thedichroic prism 111 from this polarization beam apparatus.The P polarized light that incides on thedichroic prism 111 sends by R light reflectiondichroic film 111R and the reflectiondichroic film 111B transmission of B light and from dichroic prism 111.The P polarized light incides on the quarter-wave phase-plate 112 then, is transformed into circularly polarized light and incides on the projection optical system 113.Incide that the part of surface reflection that G light on the projection optical system is configured the lens element of projection optical system turns back to quarter-wave phase-plate 112 and by its transmission, reflected light B is transformed into the S polarized light thus.This light beam incides again on thedichroic prism 111 then.

On the other hand, when G light enters thedichroic film 111R that is used to reflect R light and B light and 111B as the S polarized light, G light medium wavelength less than short wavelength's composition of the reflection/transmission boundary wavelength of the S polarized light of B light reflectiondichroic film 111B among Fig. 3 B in fact by B light reflectiondichroic film 111B reflection.Fan She light passes half-wavelength phase-plate 109 thus, thereby is transformed into the P polarized light and enters B optical polarization beam splitter 107B.In addition, do not returned and enter again half-wavelength phase-plate 109 as the P polarized light by the light component of B lightlight valve 108B modulation, thereby be transformed into the S polarized light and enter quadraturedichroic prism 111 again as the S polarized light, with further propagation, made it finally project into terrible light beam by B light reflectiondichroic film 111B reflection.

[first embodiment]

In the first embodiment of the present invention, a dichroic mirror that is formed with the dichroic film in its surface is set, between quadrature dichroic prism and polarization beam apparatus to address the above problem.

Fig. 1 is the sketch of the projection display apparatus total of first embodiment of the invention.In this structure, orthogonal X-axis, Y-axis and Z axle define in the mode shown in Fig. 1.Notice that the Z axle is taken on the direction perpendicular to the accompanying drawing paper.

The source beam that sends from thelight source 11 of lamp and recessed catoptron composition comprises the random polarization that luminous flux is substantially parallel.Source beam incides on thepolarization converter 12, thereby converts the S polarized light of electric vector orientation of oscillation (below be called the polarization direction) perpendicular to the accompanying drawing paper to.Quadraturedichroic mirror 13 is further walked and entered to light beam, in this quadrature dichroic mirror, have thedichroic mirror 13B of reflection B (promptly blue) light characteristic and have the orthogonal distribution of dichroic mirror 13RG of reflection R (promptly red) and G (promptly green) light characteristic, thereby form an X-shaped.The light that incides on thedichroic mirror 13 is resolved into B light and the complex light that comprises R light and G light by color, and their opposite toward each other directions are propagated.

The B light that color is decomposed thus is deflected mirror 14 reflection, thereby has changed its direction of propagation and incide on the polarization beam apparatus 17B that is provided with into B light.On the other hand, the complex light that comprises R light and G light separately is deflected mirror 15 reflections, thereby changed its direction of propagation, entered dichroic mirror 16 with reflection G light characteristic, color resolve into be reflected in case further the G light of propagating and by transmission so that the further R light of propagating.R light and the G light that is separated by color incides polarization beam apparatus 17R and the polarization beam apparatus 17G that is respectively the shades of colour setting thus.The polarization beam splitting face of polarization beam apparatus 17R and 17G is arranged to perpendicular to X-Y plane.When inciding shades of colour light beam on shades of colour light valve 18R, 18G and the 18B and modulated by each color signal by light valve 18R, 18G and 18B reflection.Thereby versicolor light sends from versicolor light valve 18R, 18B and 18G as mixed light, each coloured light in the mixed light comprises as the P polarized light of light modulated with as the S polarized light of non-modulation light, and incide on polarization beam apparatus 17R, the 17G and 17B of all kinds, make thus and have only that reception just is decomposed by the light modulated of each polarization beam splitting face transmission (being the P polarized light).Non-modulation light (being the S polarized light) is propagated by each polarization beam splitting face reflection and towards the direction of light source.

In versicolor decomposition light, R light and B light are formed with thedichroic mirror 21R and the 21B transmission of dichroic film respectively on it.Each

dichroic mirror

21R and 21B and the corresponding angle tilt distribution of optical axis to be scheduled to.Then, R light and B light pass half-wavelength phase-

plate

20 and 19 respectively, thereby are transformed into the S polarized light and enter quadraturedichroic prism 22 from the different planes of incidence respect to oneanother.Dichroic mirror 21R has the optical characteristics shown in Fig. 4 A, and it sees through the R light component without any problem ground.In addition,dichroic mirror 21B has the optical characteristics shown in Fig. 4 B, and it sees through the B light component without any problem ground.

On the other hand, the G light in the above-mentioned decomposition light is formed with thedichroic mirror 21G transmission of dichroic film on it, and G light enters quadraturedichroic prism 22 with constant P polarization state more then.Dichroic mirror 21G distributes with predetermined angle tilt with mode and the optical axis that is similar todichroic mirror 21B and21R.Dichroic mirror 21G has the optical characteristics shown in Fig. 4 C, and it sees through the G light component without any problem ground.In Fig. 4 A～4C, solid line is represented the characteristic of P polarized light, and dotted line is represented the characteristic of S polarized light.

The quadraturedichroic prism 22 that constitutes color combining optical comprisesdichroic film 22R with reflection R light characteristic and thedichroic film 22B with reflection B light characteristic, the orthogonal distribution of two films, form a kind of X-shaped shape, and each is orthogonal to X-Y plane and distributes, and its mode is similar to the dichroic prism in the conventional configuration.In addition,dichroic film 22R anddichroic film 22B have with prior art in the quadraturedichroic film 111R characteristic identical shown in Fig. 3 A of mentioning and the 3B with 111B.

The S polarization B light that incides on the quadraturedichroic prism 22 is reflected by B light reflectiondichroic film 22B in fact, the S polarization R light that incides on this prism is reflected by R light reflectiondichroic film 22R in fact, the P polarization G light that incides on this prism is reflecteddichroic film 22R transmission by B light reflectiondichroic film 22B and R light in fact, make that the color reach B light, R light and G light is compound or color synthetic, and these light as complex light from 22 outgoing of quadrature dichroic prism.Pass a quarter-wave phase-plate 23 from the complex light that quadraturedichroic prism 22 sends, this phase-plate arranges by this way, and promptly each orientation of oscillation of its optical axis and S polarization R light, S polarization B light and P polarization G light forms 45.Thereby the light of each color is transformed into circularly polarized light and further propagates, and projects on the screen (not shown) by projectionoptical system 24.

Fig. 2 is the distributed in three dimensions skeleton view of versicolor

polarization beam apparatus

17R, 17G and 17B,

light valve

18R, 18G and 18B, quadraturedichroic prism 22,

dichroic mirror

21R, 21G and 21B and half-wavelength phase-

plate

19 and 20.

As explanation to the research of terrible light beam cause, incide a part of circular polarization complex light on the projectionoptical system 24 be configured projectionoptical system 24 lens element surface reflection and return with further propagation.Then, the light that returns passes quarter-wave phase-plate 23, makes R light ghost component and B light ghost component be transformed into the P polarized light, and G light ghost component is transformed into the S polarized light.These light enter quadraturedichroic prism 22 as complex light from above-mentioned exit facet.

According to the optical characteristics shown in Fig. 3 A, reflecteddichroic film 22R transmission by the R light the quadrature dichroic prism in the other direction from a part of P polarization R light component that incides on the quadrature dichroic prism 22.The light path of passing (or seeing through) two quadrature

dichroic film

22R and 22B and entering G light as the R light ghost component of R transmittance part.But it is set at thedichroic mirror 21G reflection with optical characteristics shown in Fig. 4 C between quadraturedichroic prism 22 and the G polarisation of light beam splitter 17G.Because this dichroic mirror is arranged with predetermined angle tilt with respect to optical axis as previously mentioned, so left this light path by the light of dichroic mirror reflects.

According to the optical characteristics shown in Fig. 3 B, reflecteddichroic film 22B transmission by the B light the quadrature dichroic prism in the other direction from a part of P polarization B light component that incides on the quadrature dichroic prism 22.The light path of passing two quadrature

dichroic film

22R and 22B (or by this two dichroic films transmission) and entering G light as the B light ghost component of B transmittance part.But it is set at thedichroic mirror 21G reflection with optical characteristics shown in Fig. 4 C between quadraturedichroic prism 22 and the G polarisation oflight beam splitter 17G, and leaves this light path in the mode that is similar to above-mentioned R light ghost component.

According to the optical characteristics shown in Fig. 3 A, reflected by the reflection of the R light quadrature dichroic prismdichroic film 22R from a part of S polarization G light component that incides in the other direction on the quadrature dichroic prism 22.The G light ghost component that divides as the G photo-emission part is the S polarized light, enters the light path of R light and passes half-wavelength phase-plate 20, thereby be transformed into the P polarized light.This light is had thedichroic mirror 21R reflection of optical characteristics shown in Fig. 4 A, wherein thisdichroic mirror 21R is arranged between half-wavelength phase-plate 20 and the R opticalpolarization beam splitter 17R, and arrange with predetermined angle tilt with respect to optical axis in the mode that is similar todichroic mirror 21G, make light leave light path.

According to the optical characteristics shown in Fig. 3 B, reflected by the reflection of the B light quadrature dichroic prismdichroic film 22B from another part S polarization G light component that incides in the other direction on the quadrature dichroic prism 22.G light ghost component as another reflecting part of G light is the S polarized light, enters the light path of B light and passes half-wavelength phase-plate 19, thereby be transformed into the P polarized light.This light is had thedichroic mirror 21B reflection of optical characteristics shown in Fig. 4 B, wherein thisdichroic mirror 21B is arranged between half-wavelength phase-plate 19 and the B opticalpolarization beam splitter 17B, and arrange with predetermined angle tilt with respect to optical axis in the mode that is similar to

dichroic mirror

21R and 21G, make light leave light path.

As mentioned above, in the present embodiment, in the surface reflection of the lens element that is configured projectionoptical system 24 and the light that returns in the other direction along light path, because twodichroic film 22R of quadraturedichroic prism 22 and the optical characteristics of 22B and the dependence of polarization, by the R light component of twodichroic film 22R of quadrature

dichroic prism

22 and 22B transmission and B light component and all will be in fact bydichroic mirror 21R by the G light component of any one reflection in above-mentioned two dichroic mirrors, 21B and 21G depart from light path, and wherein these light components can also enter projection optical system again becomes terrible light beam by the reflection of the light valve of shades of colour light.Therefore, these light components in fact no longer enter projection optical system, and also do not become terrible light beam.

In addition, as described in conjunction with conventional configuration, in the surface reflection of the lens element that is configured projectionoptical system 24 and the light that returns along light path, will depart from light path in the other direction by the G light component of twodichroic film 22R of quadrature

dichroic prism

22 and 22B transmission with by the B light component of any one reflection in two dichroic films and R light component.Therefore in this embodiment, be configured projectionoptical system 24 lens element surface reflection and all will depart from light path basically and not produce terrible light beam along the light that light path is returned in the other direction.

[second embodiment]

The second embodiment of the present invention has the structure identical with the projection display apparatus of first embodiment shown in Figure 1, except the equipment according to second embodiment does not have

dichroic mirror

21B and 21R shown in Figure 1, has onlydichroic mirror 21G.

In the present embodiment, the optical characteristics of dichroic film 22R in the quadrature dichroic prism 22 and dichroic film 22B is different with the optical characteristics of corresponding dichroic film among first embodiment.The optical characteristics of the dichroic film among second embodiment is shown in Fig. 5 A and 5B.Fig. 5 A represents the optical characteristics of dichroic film 22R, and Fig. 5 B represents the optical characteristics of dichroic film 22B.Dichroic film 22R is to wavelength X_RsThe S polarized light reflection/transmission border is arranged, therefore shown in Fig. 5 A, and reflect S polarization R light in fact.But as for the P polarized light, dichroic film 22R is to wavelength X_RPThe P polarized light reflection/transmission border is arranged, shown in Fig. 5 A, and the therefore shortwave part of transmission P polarization R light.Dichroic film 22R is transmission B light and G light in fact, no matter B light and G only the S polarized light still be that the P polarized light is not always the case.Dichroic film 22B is to wavelength X_BSThe S polarized light reflection/transmission border is arranged, therefore shown in Fig. 5 B, and reflect S polarization R light in fact.But as for the P polarized light, dichroic film 22B is to wavelength X_BPThe P polarized light reflection/transmission border is arranged, shown in Fig. 5 B, and the therefore long wave part of transmission P polarization B light.Dichroic film 22B is transmission R light and G light in fact, no matter R light and G only the S polarized light still be that the P polarized light is not always the case.

Be used under the situation of color combining optical atdichroic film 22R that will have above-mentioned characteristic anddichroic film 22B, as the lens element reflection that has been configured projection optical system and pass the light of quarter-wave phase-plate 23 above-mentioned complex light (comprising the R of P polarization and the G light of B light and S polarization) may be in the component of cause of terrible light beam, G light is basically by the transmission of two dichroic films and reenter and be mapped on thepolarization beam apparatus 17G, makes the G light light path that is reflected out.Because according to the optical characteristics shown in Fig. 5 A and the 5B, basically all G light components are all by the dichroic film transmission of quadrature dichroic prism, so not by any one reflection among twodichroic film 22R of quadraturedichroic prism 22 and the 22B, incide on the light path of B light or R light, by the terrible beam component of thelight valve 18B of B light or R light and 18R reflection and projection.

On the other hand, according to the optical characteristics of P polarized light shown in Fig. 5 A and the 5B, R light component and B light component are respectively by partly transmission and enter G light light path ofdichroic mirror 22R and 22B.According to the optical characteristics shown in Fig. 4 C, this light incidesdichroic mirror 21G and also this mirror reflection basically, thereby leaves light path.R light and B light are entered respectively by the other parts of

dichroic film

22R or 22B reflection and pass half-wavelength phase-

plate

20 or 19, thereby are transformed into the S polarized light.Then, these light carry out

polarization beam apparatus

17R and 17B, and by the reflection of the polarization beam splitting face of each polarization beam apparatus, thereby leave light path.

As mentioned above, in the present embodiment, be configured projectionoptical system 24 lens element surface reflection and basically all leave light path along the light that light path is returned in the other direction, and do not have terrible light beam to produce.

[the 3rd embodiment]

The third embodiment of the present invention has the structure identical with the projection display apparatus of first embodiment shown in Figure 1, except the equipment according to the 3rd embodiment does not havedichroic mirror 21G shown in Figure 1, has only

dichroic mirror

21B and 21R.

In the present embodiment, dichroic film 22R in the quadrature dichroic prism 22 and 22B have the optical characteristics shown in Fig. 6 A and the 6B.Fig. 6 A represents the optical characteristics of dichroic film 22R, and Fig. 6 B represents the optical characteristics of dichroic film 22B.From Fig. 6 A as seen, dichroic film 22R reflects R light basically, no matter is S polarized light or P polarized light.Dichroic film 22R is transmission B light basically, no matter is S polarized light or P polarized light.As for G light, dichroic film 22R is the G light of transmission P polarization basically because to the reflection/transmission border of P polarized light in wavelength X_RPThe place, as shown in Figure 6A, but the long wave part of the G light of reflection S polarization because to the reflection/transmission border of S polarized light in wavelength X_RSThe place, as shown in Figure 6A.Obvious from Fig. 6 B, dichroic film 22B reflects B light basically, no matter this only the S polarized light still be the P polarized light.Dichroic film 22B is transmission R light basically, no matter this only the S polarized light still be the P polarized light.As for G light, dichroic film 22B is the G light of transmission P polarization basically, because be positioned at wavelength X for the reflection/transmission border of P polarized light_BPThe place, shown in Fig. 6 B, but the shortwave part of the G light of reflection S polarization because to the reflection/transmission border of S polarized light in wavelength X_BSThe place is shown in Fig. 6 B.

Be used under the situation of color combining optical at dichroic film 22R that will have above-mentioned characteristic and dichroic film 22B, what reflect as the lens element that is configured projection optical system may be in the light (the G light of the R of P polarization and B light and S polarization) of the cause of terrible light beam, R light and B light is basically by any one transmission among two dichroic film 22R and the 22B, and is transformed into the S polarized light by half-wavelength phase-plate 20 and 19 respectively.R light and B light incide on the dichroic mirror 21R and 21B with optical characteristics shown in Fig. 4 A and the 4B more then, and they are also incided respectively on polarization beam apparatus 17R and the 17B by these dichroic mirror transmissions basically entirely.These light are reflected by each polarization beam splitting face, thereby leave light path, as described to the routine configuration.Therefore, they can not become terrible light beam.In addition, according to the optical characteristics shown in Fig. 6 A and the 6B, basically above-mentioned R and B light component be all by dichroic film 22R and 22B reflection, therefore do not have terrible beam component by the dichroic film 22R of dichroic prism and 22B transmission and the light path that enters G light, by G light light valve 18G reflection and finally be projected.On the other hand, as for the G light from the light of projection optical system reflection, respectively according to the optical characteristics shown in Fig. 6 A and the 6B, the long wave of G light part is by dichroic film 22R reflection, and the shortwave part of G light is reflected by dichroic film 22B.Thereby according to the optical characteristics shown in Fig. 3 A and the 3B, the G light of reflection enters the light path of R light and the light path of B light respectively, arrives dichroic mirror 21R and 21B, thereby basically by dichroic mirror reflects, makes these G light components leave light path.As described, incided polarization beam apparatus 17G by the part of dichroic film 22R and 22B transmission in the G light and by its polarization beam splitting face reflection, thereby leave light path routine configuration.

As mentioned above, be configured projection optical system lens element surface reflection and leave light path along the light that light path is returned in the other direction, and do not have terrible light beam to produce.

In this embodiment,

dichroic mirror

22R and 22B have been used with optical characteristics shown in Fig. 6 A and the 6B, and also in R light light path and B light light path

dichroic mirror

21R and 21B are set respectively, the G light of surface reflection that is projected the lens element of optical system with tetrandra root becomes terrible beam component through R light light path and B light light path.But, lower because human eye is the highest for ruddiness to the susceptibility of colorama for green glow and blue light, only prevent that the easy configuration of the terrible light beam that derives from the ruddiness of projection optical system reflection from just can realize that significant terrible light beam prevents effect.Therefore,dichroic film 22R and the structure of 22B or the structure of the dichroic film that employing has optical characteristics shown in Fig. 6 A be can adopt,

dichroic mirror

21R and 21B need not to be provided with optical characteristics shown in Fig. 6 A and the 6B.In the case, structure that can simplified apparatus is not because need be provided with dichroic mirror between quadrature dichroic prism and polarization beam apparatus.

Obvious from the description of first, second and the 3rd embodiment, whether provide in the light path between shades of colour polarisation of

light beam splitter

17R, 17G or 17B should be by the light path of shades of colour light, according to being used to carry out thedichroic film 22R of the synthetic quadraturedichroic prism 22 of color and the optical characteristics of 22B determines that independently the configuration of dichroic mirror is not limited to the situation of first to the 3rd embodiment about the dichroic mirror of inclined light shaft setting with specific angle.In addition, though

dichroic mirror

21R, 21G and 21B arrange in the mode that the light that may become terrible light beam cause leaves " Z (negative Z) " direction in the above-described embodiments, clearly, are not limited to this direction, dichroic mirror also can be arranged in other mode, as long as light leaves light path.

[the 4th embodiment]

Below with reference to Fig. 7 and Fig. 8 the 4th embodiment of projection display apparatus of the present invention is described.In this embodiment, by

dichroic mirror

21R, 21G and 21B identical functions among

dichroic film

428R, 428G and the 428B realization and first to the 3rd embodiment, their arrangement is relative with the polarization beam splitting face of polarization beam apparatus.

In Fig. 7, member same as shown in Figure 1 adopts identical label to represent in the projection display apparatus, and saves giving unnecessary details they functions.

Fig. 8 is thepolarization beam apparatus 427R, the 427G that use in the present embodiment and the structure of 427B.Has such structure with in the present embodiment each

polarization beam apparatus

427R, 427G and 427B, promptly, on the bottom surface ofTp 427G-A, 427R-A or 427B-A, form a polarizing beam splitting film, on the bottom surface ofTp 427G-B, 427R-B or 427B-B, formdichroic film 428G, a 428R or 428B, and two kinds of films glue together with a tack coat.As shown in Figure 8, on theprism 427G-A, the 427R-A that constitute polarization beam apparatus and 427B-A side, shades of colour

light valve

18G, 18R and 18B are set.The light that sends from shades of colour

light valve

18G, 18R and 18B at first incides on the polarizing beam splitting film of polarization beam apparatus, makes shades of colour light be decomposed.The decomposition light of transmission is then by

dichroic film

428G, 428R and 428B transmission and to be transported to quadraturedichroic prism 22 synthetic to carry out color.Therefore, the potential terrible beam component that is projectedoptical system 24 reflection and enters

polarization beam apparatus

427G, 427R and 427B incides on

dichroic film

428G, 428R and the 428B.

Thereby after propagating in the other direction and passing quarter-wave phase-plate 23, incide in the light of quadraturedichroic prism 22 in the reflextion from lens surface that is configured projectionoptical system 24, according to the optical characteristics of the P polarized light ofdichroic film 22R shown in Fig. 3 A and the 3B and 22B, the R of a part of P polarization and B light by

dichroic film

22R and 22B transmission to enter G light light path.Then, this light incides on thedichroic film 428G ofpolarization beam apparatus 427G, but according to the optical characteristics of this light shown in Fig. 5 C, and this light beam is basically bydichroic film 428G reflection and leave light path.

On the other hand, according to the optical characteristics of the S polarized light of the dichroic film shown in Fig. 3 A and the 3B, the G light of part S polarization is entered the light path of R light and the light path of B light by thedichroic film 22R of quadrature

dichroic prism

22 and 22B reflection.Then, these light incide on the

dichroic film

428R and 428B of

polarization beam apparatus

427R and 427B, but according to the optical characteristics of this light shown in Fig. 5 A and the 5B, and this light beam is basically by

dichroic film

428R and 428B reflection and leave light path.

In addition, in conventional configuration, thereby incide in the light of quadraturedichroic prism 22 after propagating in the other direction and passing quarter-wave phase-plate 23 in the reflextion from lens surface that is configured projectionoptical system 24, this coloured light component of propagating in the other direction along the light path of corresponding color also leaves this light path.Therefore, the light that is projectedoptical system 24 reflection can not cause terrible light beam.

Under the situation of the second or the 3rd embodiment, if by being similar to the function that the polarization beam apparatus that uses among the 4th embodiment replaces dichroic mirror, and do not change the existence of dichroic mirror of all kinds among the optical characteristics of two quadrature dichroic films and each embodiment/do not exist, can obtain identical beneficial effect yet.As mentioned above, in the present embodiment, if suitably arrange

dichroic film

428G, 428R and 428B in

polarization beam apparatus

427G, 427R and 427B, thereby the lens element reflection that then is configured projection optical system is left light path at the light of propagating in the other direction.Therefore light beam can not be projected into terrible light beam.

[the 5th embodiment]

Fig. 9 is the one-piece construction sketch of the projection display apparatus of fifth embodiment of the invention.In conjunction with this structure, define orthogonal X-axis, Y-axis and Z axle in the mode shown in Fig. 9.The source beam that is essentially parallel luminous flux that sends fromlight source 31 is transformed into the P polarized light by apolarization transition device 32, and this P polarized light has the orientation of oscillation that is parallel to X-axis.This P polarization source beam is resolved into the G light that is subjected to this dichroic mirror reflects bydichroic mirror 33 colors and is subjected to the complex light of the R and the B of this dichroic mirror transmission.The G light that separates thus passes half-wavelength phase-plate 34, thus be transformed into orientation of oscillation be parallel to vertical paper the Z axle the S polarized light and enter polarization beam apparatus 36G.This G light is polarized the polarization beam splitting face reflection of beam splitter and reenters and is mapped on thereflective light valves 37G, and G light is modulated by color signal and reflected in this light valve.Then, the G light that sends from light valve 37 is polarizedbeam splitter 36G and decomposes.In this embodiment, the light modulated of G lightlight valve 37G is the P polarized light.

The mixing or the complex light of above-mentioned R light and B light are passedpolarization rotation element 35, and only the orientation of oscillation with R light changes over Z-direction, and R light is transformed into the S polarized light.R light is transformed into the S polarized light thus, and B light keeps its polarization state.Then, its mixed light incides on the polarization beam apparatus 36RB, and color resolves into R light and the B light that is subjected to the reflection of polarization beam splitting face.

Enteredreflective light valves 37R and the 37B that is provided with into shades of colour light by the R light of color decomposition as described above and B light.Inciding thelight valve 37R of corresponding color or the every coloured light on the 37B is modulated by color signal and is reflected by light valve.In this embodiment, the light modulated of the light modulated of R lightlight valve 37R and G lightlight valve 37G is the P polarized light, and each sends the mixed light of the non-modulation light of the light modulated of a branch of P of comprising polarization and S polarizationlight valve 37R and 37G.On the other hand, B lightlight valve 37B sends the mixed light of the non-modulation light of the light modulated that comprises the S polarization and P polarization.The light modulated of sending from B lightlight valve 37B incides on the polarization beam apparatus 36RB from different faces with the light modulated of sending from R lightlight valve 37R, and B light is by the reflection of this polarization beam splitting face, and R light is made two-beam be decomposed by this polarization beam splitting face transmission.

On the other hand, the decomposition light of G light incides that to carry out color on thedichroic prism 39 synthetic.The R and the B light that decompose incide on thedichroic mirror 38 that is formed with the dichroic film on its surface, and are haddichroic mirror 38 transmissions of optical characteristics shown in Figure 12, thereby further propagate and incide on the dichroic prism 39.The characteristic ofdichroic mirror 38 is described in theback.Dichroic mirror 38 is with respect to the angle tilt setting of optical axis to be scheduled to.

Be used to carry out the syntheticdichroic prism 39 of color within it portion adichroic film 39D is arranged.The optical characteristics ofdichroic film 39D as shown in figure 10.

Incide P polarization G light on thedichroic prism 39 according to its optical characteristics as shown in figure 10 bydichroic film 39D transmission.The R light of P polarization and the B light of S polarization is basically bydichroic film 39D reflection, makes these light and above-mentioned G light color synthesize, thereby fromdichroic prism 39 outgoing.

R, G that sends fromdichroic prism 39 and the complex light of B are passed quarter-wave phase-plate 40, thereby are transformed into circularly polarized light.This light is further propagated and is entered projectionoptical system 41, is projected on the screen (not shown).Thereby reflect in the light component of propagating in the other direction in the lenticular element surfaces that is configured projectionoptical system 41, R light and G light are transformed into the S polarized light by quarter-wave phase-plate 40 respectively, B light is transformed into the P polarized light by quarter-wave phase-plate 40 so that further propagate, and makes these light again from enteringdichroic prism 39 in the other direction.Enteringdichroic prism 39 to carry out in the synthetic light of color, the G light of S polarization incidesdichroic film 39D, and its shorter wavelength part and longer wavelength part are reflected bydichroic film 39D according to polarization beam splitting shown in Figure 10 optical characteristics in the face of the S polarized light.The part of reflection or the G light component of S polarization incidedichroic mirror 38, and are reflected bydichroic mirror 38 according to the optical characteristics of its S polarized light, thereby leave light path.

Ifdichroic mirror 38 is not set, then will be incided on the polarization beam apparatus 36RB by the G light component ofdichroic film 39D reflection, be polarized the beam-splitting surface reflection, incide on the B light

light valve

37B, 37B reflects by light valve, make the non-modulation light component of G light to turn back to projectionoptical system 41 through polarization beam apparatus 36RB anddichroic prism 39, and with projection G ghost light beam.

Though the front is described in conjunction with the dichroic prism 39 with optical characteristics shown in Figure 10, and a kind of dichroic prism with optical characteristics shown in Figure 11 also can be arranged.When use has the dichroic prism 39 of optical characteristics shown in Figure 11, be projected optical system reflection and return the R that comprises the S polarization that enters dichroic prism 39 in the other direction and the light beam of the B light of G light and P polarization in, the longer wavelength part of G light will be by dichroic film 39D reflection, and the longer wavelength part of B light will be by dichroic film 39D transmission.G reflection of light part will be reflected by dichroic mirror 38 and leave light path, but B optical transmission part will be reflected by light valve 37G after passing polarization beam apparatus 36G and turn back to projection optical system to become terrible light beam.For the above-mentioned light beam that may become terrible light beam is broken away from outside the light path, on the light path between polarization beam apparatus 36G and the dichroic prism 39, a dichroic mirror with optical characteristics shown in Figure 13 is set, makes the above-mentioned B light that incides on the catoptron to be reflected and leave light path about inclined light shaft.Perhaps, replace such catoptron is set, can form a dichroic film with optical characteristics same as shown in Figure 11 in polarization beam apparatus 36, generation type is relative with the polarization beam splitting face, as shown in Figure 8, thereby B light is broken away from light path.

The present invention relates to a kind of projection optical system as mentioned above, the light modulated that wherein is included in from the shades of colour light of a plurality of reflective light valves emissions is decomposed reception by the polarization beam apparatus that is provided with for shades of colour light, and the color combining optical with a dichroic film is synthetic, synthetic light is projected the optical system projection, also has the quarter-wave phase-plate on the light path that is arranged between color combining optical and the projection optical system in the equipment.In this equipment, be configured the lens element reflection of projection optical system and reenter and be mapped to color combining optical and resolve into shades of colour component with the dichroic film color that the light of propagating along light path is comprised in the color combining optical in the other direction, the situation of propagating in normal direction that these components and light depend on owing to the optical characteristics of dichroic film due to the difference of polarization direction is different.Therefore, the light of decomposition is along propagating on other the coloured light light path that is different from each corresponding coloured light, and these light reenter by the light valve transmission of other coloured light and through color combining optical and be mapped on the projection optical system, makes this light beam be projected into terrible light beam.In the present invention, the dichroic mirror have the predetermined optical characteristic and to distribute about inclined light shaft is set on the light path between the polarization beam splitting face of color combining optical and shades of colour polarisation of light beam splitter, makes that above-mentioned may be that the light component of potential terrible light beam is reflected and leaves light path.Therefore, can avoid the generation of terrible light beam, and image that can the high image contrast of projection.

Claims

1. projection display apparatus comprises:

2. projection display apparatus as claimed in claim 1, wherein being polarized beam splitter, to incide the electric vector orientation of oscillation of light of the light of first kind of color on the dichroic prism and second kind of color after decomposing orthogonal.

3. projection display apparatus as claimed in claim 1 wherein is arranged between the polarization beam splitting face of described shades of colour polarisation of light beam splitter and the described dichroic prism dichroic film at least one light path in the shades of colour light light path and is arranged in the light path between described polarization beam apparatus and the described dichroic prism.

4. between the projection display apparatus as claimed in claim 1, the polarization beam splitting face that wherein is arranged on described shades of colour polarisation of light beam splitter and described dichroic prism in the shades of colour light light path dichroic film at least one light path be arranged within the described polarization beam apparatus in the mode relative with described polarization beam splitting face.

5. projection display apparatus comprises:

6. projection display apparatus as claimed in claim 5 wherein is arranged between the polarization beam splitting face of described shades of colour polarisation of light beam splitter and the described quadrature dichroic prism dichroic film at least one light path in the shades of colour light light path and is arranged in the light path between described polarization beam apparatus and the described quadrature dichroic prism.

7. between the projection display apparatus as claimed in claim 5, the polarization beam splitting face that wherein is arranged on described shades of colour polarisation of light beam splitter and described quadrature dichroic prism in the shades of colour light light path dichroic film at least one light path be arranged within the described polarization beam apparatus in the mode relative with described polarization beam splitting face.

8. projection display apparatus comprises:

Reflective light valves for the ruddiness setting;