CN111123481A - An ultra-short-focus projection lens based on catadioptric optical lens - Google Patents

Abstract

Translated fromChinese

本发明公开了一种基于折反式光学镜片的超短焦投影镜头，其包括沿着光路方向依次设置的图像源、折射透镜组、折反式光学镜片和屏幕，折反式光学镜片包含一个折射面和一个反射面，光线从折射透镜组出射后，经过折反式光学镜片的折射面折射后经过反射面反射，然后再次经过折射面出射投影到屏幕上。本发明通过单一折反式光学镜片实现了双折射面加反射面的效果，在不增加系统复杂度的前提下为校正系统像差提供了更多的自由度，使系统性能更好，且降低了系统成本。

The invention discloses an ultra-short-focus projection lens based on a catadioptric optical lens, which comprises an image source, a refractive lens group, a catadioptric optical lens and a screen sequentially arranged along the direction of the optical path. The catadioptric optical lens includes a A refracting surface and a reflective surface, after the light emerges from the refracting lens group, it is refracted by the refracting surface of the catadioptric optical lens, then reflected by the reflective surface, and then projected on the screen through the refracting surface again. The present invention realizes the effect of a birefringent surface and a reflective surface through a single refracting optical lens, provides more degrees of freedom for correcting system aberrations without increasing the complexity of the system, makes the system performance better, and reduces the system cost.

Description

Ultra-short focus projection lens based on refraction and reflection type optical lens

Technical Field

The present disclosure relates to lenses, and particularly to an ultra-short-focus projection lens based on a catadioptric optical lens.

Background

With the development of the ultra-short-focus projection technology, the ultra-short-focus projection objective lens is widely applied to the fields of education, commerce, military, family entertainment and the like. At present, ultra-short focus projection systems are gradually developing towards the trend of large screen, high definition, high resolution, and low projection ratio. As a core component of the ultra-short-focus projection system, the ultra-short-focus projection lens determines the performance of the ultra-short-focus projection system, such as the throw ratio, the imaging quality of the projection image, and the system volume, and gradually develops toward a short focal length, a large field angle, and a large screen.

The conventional ultra-short-focus projection lens mainly adopts a structural form of a refraction lens group and a single-chip reflector, but in order to realize a large field angle, most of focal power and field angle expansion tasks of a system fall on the single-chip reflector, so that the requirement on the reflector is high, the sensitivity of the reflector is high, and industrial popularization and application are difficult to realize; if the complexity of the reflector is to be simplified, more lenses are used, which leads to a complicated optical path structure of the system, and inevitably leads to an increase in cost.

Disclosure of Invention

In view of the above, an object of the present invention is to provide an ultra-short-focus projection lens based on a catadioptric optical lens, which, by using the catadioptric optical lens, not only improves the degree of freedom of optimization of the system to the maximum extent without increasing the complexity of the optical path structure, and makes the system performance better, but also reduces the system cost.

The technical scheme adopted by the invention for solving the technical problem is as follows:

the utility model provides an ultrashort burnt projection lens based on refraction and reflection formula optical lens, its includes image source, refraction lens group, refraction and reflection formula optical lens and the screen that sets gradually along the light path direction, and refraction and reflection formula optical lens contains a refracting surface and a plane of reflection, and light is from refraction lens group outgoing back, and through the plane of reflection after refraction of refraction formula optical lens, then through the plane of reflection outgoing projection to the screen once more.

Preferably, the radius of curvature R1 of the refractive surface of the catadioptric optical lens satisfies: l R1| <400, the radius of curvature R2 of the reflective surface of the catadioptric optical lens satisfies: | R2| <2| R1 |.

Preferably, the surface of the catadioptric optical lens is a spherical surface, an aspherical surface or a free-form surface.

Preferably, the refractive lens group includes at least two lens groups, and the power of the lens group close to the catadioptric optical lens direction is negative.

Preferably, one side surface of the catadioptric optical lens is coated to form a reflecting surface, and the coating material is a silver film, an aluminum film or a dielectric film.

The invention has the beneficial effects that: compared with the refraction and reflection type ultrashort-focus projection lens adopting a common reflector, the refraction and reflection type optical lens disclosed by the invention comprises two surfaces, wherein the first surface is a refraction surface, the second surface is a reflection surface, light rays are refracted from the first surface of the lens and then reflected by the second surface, then the light is refracted by the first surface again and is emitted to be projected on a screen, and through the way that the light passes through the first surface twice, on the premise of not increasing the optical element, a refraction surface is added, namely, the effect of the double refraction surface and the reflecting surface is realized by adopting a single refraction and reflection type lens, which not only provides more degrees of freedom for correcting the aberration of the system, further improves the performance of the system, also, from a lens manufacturing perspective, the number of optical elements, and thus the number of molds used, and compared with the method for manufacturing a single reflector mold, the method improves the utilization rate of the mold and reduces the cost of the system.

Drawings

FIG. 1 is a schematic structural view ofembodiment 1 of the present invention;

FIG. 2 is a schematic view of a partial structure ofembodiment 1 of the present invention;

FIG. 3 is a light path diagram ofembodiment 1 of the present invention;

FIG. 4 is a graph of field curvature and distortion for example 1 of the present invention;

FIG. 5 is a light path diagram ofembodiment 2 of the present invention;

FIG. 6 is a graph of field curvature and distortion for example 2 of the present invention;

FIG. 7 is a light path diagram of embodiment 3 of the present invention;

FIG. 8 is a graph showing the field curvature and distortion in example 3 of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments.

Referring to fig. 1 to 8, the invention provides an ultra-short-focus projection lens based on a catadioptricoptical lens 13, which includes aDMD chip 400, aprotective glass 200, acoupling prism 300, arefractive lens group 100, the catadioptricoptical lens 13 and a screen, which are sequentially arranged along a light path direction, wherein the catadioptricoptical lens 13 includes a refractingsurface 13b and a reflecting surface 13a, and after light exits from therefractive lens group 100, the light is refracted by the refractingsurface 13b of the catadioptricoptical lens 13, reflected by the reflecting surface 13a, and then exits through the refractingsurface 13b again and is projected onto the screen.

Example 1

The radius of curvature R1 of therefractive surface 13b of the catadioptricoptical lens 13, i.e., the left side surface thereof, satisfies: i R1| <400, the radius of curvature R2 of the reflective surface 13a of the catadioptricoptical lens 13, i.e., the right side surface thereof, satisfies: | R2| <2| R1 |.

The refractive index Nd of the catadioptricoptical lens 13 satisfies: 1.4< Nd <1.9, and the Abbe number Vd of the catadioptricoptical lens 13 satisfies: 55< Vd < 60.

Therefractive power Φ 13 of the catadioptricoptical lens 13 satisfies: 0.04< |Φ 13| < 0.06.

Referring to fig. 1, therefractive lens group 100 includes afirst lens group 101, asecond lens group 102, athird lens group 103, and afourth lens group 104, which are sequentially disposed along an optical path direction, and thefourth lens group 104 is a lens group closest to the catadioptricoptical lens 13. Therefractive power Φ 101 of thefirst lens group 101 satisfies: 0.04< |Φ 101| <0.05, and thepower Φ 102 of thesecond lens group 102 satisfies: 0.00005< |Φ 102| <0.00015, thepower Φ 103 of thethird lens group 103 satisfies: 0.008< |Φ 103| <0.009, and thepower Φ 104 of thefourth lens group 104 satisfies:Φ 104<0, and 0.007< |Φ 104| < 0.008. Thefirst lens group 101 is a back focus group and is used for compensating errors of back focus assembly; thesecond lens group 102 and thethird lens group 103 are focusing groups for adjusting focal lengths at different object distances; thefourth lens group 104 is a fixed group for correcting aberrations such as astigmatism and curvature of field caused by the field of view.

As a preferable scheme of the present embodiment, thefirst lens group 101 includes afirst lens 1, asecond lens 2, a third lens 3, afourth lens 4, afifth lens 5, asixth lens 6, and a seventh lens 7, which are sequentially arranged along the optical path direction, adiaphragm 14 is arranged between thesixth lens 6 and the seventh lens 7, and thefocal power Φ 1 of thefirst lens 1 satisfies: 0.01< |Φ 1| <0.03, thesecond lens piece 2 and the third lens piece 3 are cemented together to form a cemented lens, and the total optical power Φ 23 of thesecond lens piece 2 and the third lens piece 3 satisfies: 0.02< | Φ 23| <0.03, the fourth optic 4 and the fifth optic 5 are cemented together to form a cemented lens, the total optical power Φ 45 of the fourth optic 4 and the fifth optic 5 satisfies: 0.03< | Φ 45| <0.04, and thepower Φ 6 of thesixth lens 6 satisfies: 0.04< |Φ 6| <0.05, theoptical power Φ 1 of thefirst lens 1 satisfies: 0.06< | Φ 7| < 0.07.

Thesecond lens group 102 includes aneighth lens 8, and theoptical power Φ 8 of theeighth lens 8 satisfies: 0.00005< |Φ 8| < 0.00015.

Thethird lens group 103 includes a ninth lens 9 and atenth lens 10 arranged in this order along the optical path direction, and the power Φ 9 of the ninth lens 9 satisfies: 0.008< | Φ 9| <0.01, and thepower Φ 10 of thetenth lens 10 satisfies: 0.0015< |Φ 10| < 0.0025.

Thefourth lens group 104 includes aneleventh lens 11 and atwelfth lens 12 arranged in this order along the optical path direction, and thepower Φ 11 of theeleventh lens 11 satisfies: 0.0015< |Φ 11| <0.0025, thepower Φ 12 of thetwelfth lens 12 satisfies: 0.0035< |Φ 12| < 0.005.

In this embodiment, one side surface of the catadioptricoptical lens 13 is coated to form the reflecting surface 13a, and the coating material is an emitting film such as a silver film, an aluminum film, or a dielectric film. The lens can be formed by cold processing of glass, or can be formed by mould pressing of glass or injection molding of plastic materials, and the lens surface shape comprises a spherical surface, an aspheric surface or a free-form surface. The projection display technology corresponding to the invention can adopt LCD projection, DLP projection or LCOS projection and the like.

Compared with the refraction and reflection type ultrashort-focus projection lens adopting a common reflector, the refraction and reflection typeoptical lens 13 disclosed by the invention comprises two surfaces, wherein the first surface is arefraction surface 13b, the second surface is a reflection surface 13a, light rays are refracted from the first surface of the lens, reflected by the second surface, refracted by the first surface again and projected onto a screen, onerefraction surface 13b is added in a mode that the light rays pass through the first surface twice, namely, the effect of thedouble refraction surface 13b and the reflection surface 13a is realized by adopting a single refraction and reflection type lens on the premise of not increasing optical elements, so that more degrees of freedom are provided for correcting system aberration, the system performance is further improved, the number of optical elements is reduced from the angle of lens manufacturing, the using number of molds is reduced, and compared with the mode of manufacturing a single reflector, the utilization rate of the die is improved, and the cost of the system is reduced.

Fig. 4 is a graph of field curvature and distortion ofembodiment 1 of the present invention, and it can be seen that the present embodiment has a smaller degree of distortion.

In this embodiment, the surface equation of the aspheric surface used for the catadioptric aspheric optical lens is as follows:

wherein

c is the curvature of the aspheric apex, K is the conic coefficient, a1, a2, A3, a4, a5, a6 are the high-order aspheric coefficients.

Tables 1 and 2 below are the basic data for example 1 of the present invention:

TABLE 1

TABLE 2

Example 2

Fig. 5 showsembodiment 2 of the present invention, which has a similar structure toembodiment 1, and the difference between this embodiment andembodiment 1 lies in the structure of therefractive lens group 100, in this embodiment, therefractive lens group 100 includes 3 lens groups. Fig. 6 is a graph of field curvature and distortion ofembodiment 2 of the present invention, which shows that the present embodiment has a smaller degree of distortion.

Example 3

Fig. 7 shows embodiment 3 of the present invention, which has a similar structure toembodiment 1, and the difference is the structure of therefractive lens group 100, in this embodiment, therefractive lens group 100 includes 2 lens groups. Fig. 8 is a graph of field curvature and distortion of embodiment 3 of the present invention, which shows that the present embodiment has a smaller degree of distortion.

A common feature of the above 3 embodiments is: therefractive lens group 100 includes at least two lens groups, in which the power of the lens group in the direction close to the catadioptricoptical lens 13 is negative, and the lens group is used to correct aberrations such as astigmatism, curvature of field, and the like caused by the field of view.

In summary, the catadioptricoptical lens 13 disclosed in the present invention can achieve better optical performance and good projection imaging effect when combined with therefractive lens groups 100 having different numbers of groups.

The above description is only a preferred embodiment of the present invention, and all equivalent modifications within the scope of the present invention as described and claimed herein should be understood to fall within the scope of the appended claims.

Claims (5)

Translated fromChinese

1.一种基于折反式光学镜片的超短焦投影镜头，其特征在于，其包括沿着光路方向依次设置的图像源、折射透镜组(100)、折反式光学镜片(13)和屏幕，所述的折反式光学镜片(13)包含一个折射面(13b)和一个反射面(13a)，光线从折射透镜组(100)出射后，经过所述的折反式光学镜片(13)的折射面(13b)折射后经过反射面(13a)反射，然后再次经过所述折射面(13b)出射投影到屏幕上。1. An ultra-short-focus projection lens based on a catadioptric optical lens, characterized in that it comprises an image source, a refractive lens group (100), a catadioptric optical lens (13) and a screen sequentially arranged along the optical path direction , the catadioptric optical lens (13) comprises a refraction surface (13b) and a reflection surface (13a), after the light exits from the refractive lens group (100), it passes through the catadioptric optical lens (13) The refracting surface (13b) of the refracting surface (13b) is refracted and then reflected by the reflective surface (13a), and then is projected onto the screen through the refracting surface (13b) again.2.根据权利要求1所述的一种基于折反式光学镜片的超短焦投影镜头，其特征在于，所述折反式光学镜片(13)的折射面(13b)的曲率半径R1满足：|R1|<400，所述折反式光学镜片(13)的反射面(13a)的曲率半径R2满足：|R2|<2|R1|。2. The ultra-short-focus projection lens based on a catadioptric optical lens according to claim 1, wherein the radius of curvature R1 of the refractive surface (13b) of the catadioptric optical lens (13) satisfies: |R1|<400, the radius of curvature R2 of the reflection surface (13a) of the catadioptric optical lens (13) satisfies: |R2|<2|R1|.3.根据权利要求1所述的一种基于折反式光学镜片的超短焦投影镜头，其特征在于，所述折反式光学镜片(13)的面型为球面、非球面或自由曲面。3 . The ultra-short-focus projection lens based on a catadioptric optical lens according to claim 1 , wherein the surface shape of the catadioptric optical lens ( 13 ) is a spherical surface, an aspherical surface or a free-form surface. 4 .4.根据权利要求1所述的一种基于折反式光学镜片的超短焦投影镜头，其特征在于，所述折射透镜组(100)包括至少两个透镜组，其中靠近折反式光学镜片(13)方向的透镜组的光焦度为负。4. The ultra-short-focus projection lens based on a catadioptric optical lens according to claim 1, wherein the refractive lens group (100) comprises at least two lens groups, wherein the refractive lens group is close to the catadioptric optical lens The refractive power of the lens group in the (13) direction is negative.5.根据权利要求1所述的一种基于折反式光学镜片的超短焦投影镜头，其特征在于，所述折反式光学镜片(13)的一个侧面镀膜以形成所述的反射面(13a)，所述的镀膜材料为银膜、铝膜或介质膜。5. The ultra-short-focus projection lens based on a catadioptric optical lens according to claim 1, wherein one side surface of the catadioptric optical lens (13) is coated to form the reflective surface (13). 13a), the coating material is silver film, aluminum film or dielectric film.

Images