CN213876169U - Compact augmented reality near-to-eye device - Google Patents

Abstract

The utility model discloses a near-to-eye device of compact augmented reality relates to augmented reality and shows technical field. The device comprises an LCoS module, an optical machine system and a volume holographic slab waveguide set; the incident surface of the optical-mechanical system is parallel to the emergent surface of the LCoS module, and the optical-mechanical system is used for receiving light emergent from the LCoS module; the emergent surface of the optical-mechanical system is adjacent to the upper surface of the volume holographic slab waveguide set, and the optical-mechanical system is used for converting the LED light source into polarized light and then emergent the polarized light to the volume holographic slab waveguide set; the volume holographic flat waveguide group is used for diffractively transmitting the polarized light and coupling out for imaging. The utility model discloses can improve the light efficiency, realize the pupil extension, guarantee the continuity and the integrality of final image, improve the light and shade stripe that shows the image, solve close chromatic light and crosstalk serious problem.

Description

Compact augmented reality near-to-eye device

Technical Field

The utility model relates to an augmented reality shows technical field, especially relates to a near-to-eye device of compact augmented reality.

Background

The augmented reality technology aims to superimpose a virtual image generated by a computer to a real environment in real time, so that human eyes observe a scene with fusion of reality and virtuality, thereby enhancing real environment information.

Therefore, the main problem in the near-eye display device based on the augmented reality technology is how to reduce the volume and weight of the display device, provide sufficient information amount and angle of view, and realize the lightness of the device and the near-eye three-dimensional rendering effect with high spatial resolution and high angular resolution.

However, in the current stage, the microdisplay in the near-eye display device generally needs a high-power and high-brightness illumination unit, which is not favorable for the integration optimization of the system. On the other hand, if a single-layer composite type volume holographic grating waveguide is used for transmitting color images, the problem of serious crosstalk of similar color light can occur. And if the R, G, B three-color light is respectively transmitted by adopting the multilayer monochromatic volume holographic grating waveguide, the dynamic field range of the holographic waveguide can be greatly limited due to the angle selectivity of the volume holographic grating, and the brightness of the coupled image is too low to meet the brightness requirement of the augmented reality display device on the output image.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a near-to-eye device of compact augmented reality to improve the light efficiency when display device adopts compound grating propagation color image, realize the pupil extension, guarantee the continuity and the integrality of final image, improve the light and shade stripe of display image, solve close chromatic light and crosstalk serious problem.

To achieve the above objects, an embodiment of the present invention provides a compact augmented reality near-to-eye device, including an LCoS module, an optical engine system, and a volume hologram slab waveguide set; the incidence surface of the optical-mechanical system is parallel to the emergent surface of the LCoS module, and the optical-mechanical system is used for receiving the light emergent from the LCoS module; the emergent surface of the optical-mechanical system is adjacent to the upper surface of the volume holographic slab waveguide group, and the optical-mechanical system is used for converting the light emitted by the LCoS module into polarized light and then emitting the polarized light to the volume holographic slab waveguide group; the volume holographic slab waveguide group comprises a plurality of layer volume holographic slab waveguides, and each volume holographic slab waveguide comprises an adjustable attenuation sheet, an in-coupling volume holographic grating, an out-coupling volume holographic grating and a waveguide plate; the adjustable attenuation sheet is arranged on the upper surface of the waveguide plate and is positioned at the coupling end of the volume holographic slab waveguide; the coupling-in body holographic grating and the coupling-out body holographic grating are arranged on the lower surface of the waveguide plate and are respectively positioned at the coupling-in end and the coupling-out end of the body holographic slab waveguide; and the volume holographic flat waveguide group is used for diffracting and transmitting the polarized light and coupling out for imaging.

Preferably, the compact augmented reality near-to-eye device further comprises an LED light source comprising R, G and a B three-color light source, and a controller for controlling the LED light source to rapidly time-share light R, G and the B three-color light source to realize color illumination.

Preferably, the optical-mechanical system comprises a beam splitter prism, a polarizer, a first half-wave plate, a first quarter-wave plate, a concave mirror, a second quarter-wave plate, a convex mirror and a second half-wave plate; the polaroid, the concave mirror, the convex mirror and the second half-wave plate are respectively arranged on different end face sides of the beam splitter in parallel; the first half-wave plate is arranged between the polaroid and the beam splitter prism; the first quarter-wave plate is arranged between the concave mirror and the beam splitter prism; the second quarter-wave plate is arranged between the convex mirror and the beam splitter prism; the second half-wave plate is arranged between the volume holographic slab waveguide group and the beam splitter prism.

Preferably, the first end face of the beam splitter prism parallel to the polarizing plate is parallel to the adjustable attenuation plate of the volume holographic slab waveguide set; the beam splitting prism is parallel to the second end face of the first quarter-wave plate, is parallel to the third end face of the second quarter-wave plate, and is perpendicular to the first end face.

Preferably, the volume holographic slab waveguide set comprises three layers of overlapped volume holographic slab waveguides, namely a first volume holographic slab waveguide, a second volume holographic slab waveguide and a third volume holographic slab waveguide; the incoupling volume holographic grating of the first volume holographic slab waveguide diffracts only red light; the incoupling volume holographic grating of the second volume holographic slab waveguide diffracts only green light; the incoupling volume holographic grating of the third volume holographic slab waveguide diffracts only blue light.

Preferably, the in-coupling volume holographic grating and the out-coupling volume holographic grating each comprise two identical reflective volume holographic gratings that are compositely stacked with each other.

Preferably, the incoupling volume holographic grating and the outcoupling volume holographic grating are mirror-symmetrical.

Preferably, the material of the waveguide plate is transparent optical glass or transparent optical plastic.

Preferably, the in-coupling volume holographic grating and the out-coupling volume holographic grating are multiplexed volume holographic gratings manufactured based on an angular multiplexing technique.

The embodiment of the utility model provides a, following beneficial effect has:

the utility model provides a near-to-eye device of compact augmented reality utilizes the self-luminous LCoS module that has integrateed LCoS module and LED light source can provide the output light of high brightness and the characteristics of low-power consumption, designs little and exquisite, the high-efficient little display optical system of high efficiency, reduces the volume and the weight of component by a wide margin, reduces the system size and makes the structure more compact simultaneously, is fit for the human body and wears. Meanwhile, the multiplexing volume holographic grating manufactured based on the angle multiplexing technology is used as a light coupling-in/coupling-out device to acquire three-dimensional virtual object image information at a multi-angle channel, so that the dynamic range observed by human eyes is increased, and the view field is expanded. On the other hand, because current display device adopts the compound type body holographic grating waveguide of individual layer to propagate the colour image, has close chromatic light and crosstalks serious problem, then the embodiment of the utility model provides an adopt multilayer monochromatic body holographic grating waveguide to transmit R, G, B three-color light respectively for solve close chromatic light and crosstalks serious problem. And the embodiment of the utility model provides an in volume holographic waveguide's coupling in/coupling out device adopts two compound volume holographic grating that pile up the constitution, can effectively reuse the 0 th order diffraction light that loses when propagating the color image to improve the light efficiency, can solve among the prior art because the angle selectivity of monochromator holographic grating, the luminance of coupling out image is low excessively, is difficult to satisfy the technical problem of augmented reality display device to the luminance demand of output image. Meanwhile, pupil expansion can be realized, the continuity and the integrity of the final image are ensured, and the purpose of displaying light and shade stripes of the image is improved.

Drawings

In order to more clearly illustrate the technical solution of the present invention, the drawings required for the embodiments will be briefly described below, and obviously, the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.

Fig. 1 is a schematic structural diagram of a compact augmented reality near-to-eye device according to an embodiment of the present invention;

fig. 2 is a schematic structural diagram of an optical-mechanical system in a compact augmented reality near-to-eye device according to an embodiment of the present invention;

fig. 3 is a schematic structural diagram of a volume holographic slab waveguide set in a compact augmented reality near-to-eye device according to an embodiment of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.

It should be understood that the step numbers used herein are for convenience of description only and are not intended as limitations on the order in which the steps are performed.

It is to be understood that the terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in the specification and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

The terms "comprises" and "comprising" indicate the presence of the described features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

The term "and/or" refers to and includes any and all possible combinations of one or more of the associated listed items.

Referring to fig. 1, fig. 1 is a schematic structural diagram of a compact augmented reality near-to-eye device according to an embodiment of the present invention. The embodiment of the utility model provides a compact augmented reality near-to-eye device, including LCoS module 1, optical-mechanical system 2 and volume holographicslab waveguide group 3; the incidence surface of the optical-mechanical system 2 is parallel to the emergence surface of the LCoS module 1, and the optical-mechanical system 2 is used for receiving light emergent from the LCoS module 1; the emergent surface of the optical-mechanical system 2 is adjacent to the upper surface of the volume holographicslab waveguide group 3, and the optical-mechanical system 2 is used for converting light emitted by the LCoS module into polarized light and then emitting the polarized light to the volume holographicslab waveguide group 3; the volume holographicslab waveguide group 3 comprises a plurality of layer volume holographic slab waveguides, and each volume holographic slab waveguide comprises an adjustable attenuation sheet, an incoupling volume holographic grating, an outcoupling volume holographic grating and a waveguide plate; the adjustable attenuation sheet is arranged on the upper surface of the waveguide plate and is positioned at the coupling end of the volume holographic slab waveguide; the coupling-in body holographic grating and the coupling-out body holographic grating are arranged on the lower surface of the waveguide plate and are respectively positioned at the coupling-in end and the coupling-out end of the body holographic slab waveguide; the volume holographicslab waveguide group 3 is used for diffractively transmitting the polarized light and coupling out for imaging.

The embodiment of the utility model provides a near-to-eye device of compact augmented reality still includes LED light source and controller, and the LED light source includes R, G and B three-colour light source, and the controller is used for controlling the quick timesharing of LED light source and lights R, G and B three-colour light source to realize the colored illumination. In this embodiment, the controller is a computer, the LED light source in the self-luminous LCoS module 1 is controlled by the computer, and color illumination is realized by quickly lighting R, G, B light sources in a time-sharing manner.

The embodiment adopts the self-luminous LCoS (liquid Crystal on silicon) display integrated with the LCoS module and the LED light source to provide high-brightness output light and low power consumption, designs a small and exquisite high-efficiency micro-display optical system, greatly reduces the volume and weight of elements, reduces the system size, simultaneously has a more compact structure, and is suitable for being worn by human bodies. Meanwhile, the multiplexing volume holographic grating manufactured based on the angle multiplexing technology is used as an optical coupling-in/coupling-out device to achieve the purpose that three-dimensional virtual object image information is obtained at a multi-angle channel, the dynamic range observed by human eyes is greatly increased, and therefore the view field is expanded.

Referring to fig. 2, fig. 2 is a schematic diagram illustrating a specific structure of an optical-mechanical system in a compact augmented reality near-to-eye device according to an embodiment of the present invention. In the present embodiment, the optical-mechanical system 2 includes a beam-splitting prism 211, apolarizer 212, a first half-wave plate 213, a first quarter-wave plate 214, aconcave mirror 215, a second quarter-wave plate 216, aconvex mirror 217, and a second half-wave plate 218; thepolarizing plate 212, theconcave mirror 215, the convexmirror 217, and the second half-wave plate 218 are respectively disposed in parallel on different end face sides of thebeam splitter prism 211; the first half-wave plate 213 is disposed between thepolarizing plate 212 and thebeam splitting prism 211; the first quarter-wave plate 214 is disposed between theconcave mirror 215 and thebeam splitting prism 211; the secondquarter wave plate 216 is disposed between the convexmirror 217 and thebeam splitter prism 211; the second half-wave plate 218 is disposed between the volume hologramslab waveguide set 3 and thebeam splitting prism 211.

Thebeam splitter prism 211 is a Polarization Beam Splitter (PBS), which is an optical element for separating the horizontal polarization and the vertical polarization of light, and splits incident unpolarized light into two vertical linearly polarized lights. The polarization beam splitter prism is an optical element which is characterized in that a multilayer film structure is plated on the inclined plane of a right-angle prism, then a cubic structure is glued, the P polarization component is completely transmitted, and most of S polarization component is reflected (at least more than 90%) after the light passes through the multilayer film structure for multiple times at the Brewster angle by utilizing the properties that the P polarization transmission rate is 1 and the S polarization transmission rate is less than 1 when the light is incident at the Brewster angle. It should be noted that the working effect of the polarization splitting prism is wavelength limited. In addition, the purity requirements for polarization are high and a glan thompson prism can be used.

In one embodiment, thebeam splitter prism 211 is parallel to the first end surface of thepolarizer 212 and parallel to theadjustable attenuator 311 of the volume hologramslab waveguide set 3; thebeam splitter prism 211 is parallel to the second end surface of the first quarter-wave plate 214, parallel to the third end surface of the second quarter-wave plate 216, and perpendicular to the first end surface.

In this embodiment, when a three-dimensional color virtual object image is loaded on the LCoS module 1, light emitted from the LCoS display is diffraction image light which is modulated by the three-dimensional color virtual object image and carries information of the three-dimensional color virtual object image, and then the diffraction image light is incident to the optical-mechanical system 2. The diffraction image light carrying the image information of the three-dimensional color virtual object forms P-polarized light perpendicular to the incident plane through thepolarizer 212 in the optical-mechanical system 2, and is converted into S-polarized light through the first half-wave plate 213. The light enters thebeam splitter 211, is totally reflected by a beam splitting film of the beam splitter and enters the concave mirror 215 (wherein theconcave mirror 215 and theconvex mirror 217 are respectively a concave mirror and a convex mirror capable of reflecting light) after passing through the first quarter-wave plate 214, and is reflected by theconcave mirror 215 and then converted into P-polarized light through the first quarter-wave plate 214 again. The P-polarized light reaches the beam splitting film of the beam splitter prism and is transmitted completely, then passes through the secondquarter wave plate 216 and reaches theconvex mirror 217, and after being reflected by theconvex mirror 217, the P-polarized light is converted into S-polarized light through the secondquarter wave plate 216. Then, after being totally reflected by the beam splitting film of the beam splitter prism, the light is totally converted into P-polarized light through the second half-wave plate 218, and finally the P-polarized light is incident to the volume hologram slab waveguide set.

Referring to fig. 3, fig. 3 is a schematic structural diagram of a volume holographic slab waveguide set in a compact augmented reality near-to-eye device according to an embodiment of the present invention. The existing display device adopts a single-layer composite type volume holographic grating waveguide to transmit a color image, so that the problem of serious crosstalk of similar color light exists, and the embodiment adopts a multilayer single-layer composite type volume holographic grating waveguide to respectively transmit R, G, B three-color light so as to solve the problem of serious crosstalk of the similar color light. However, due to the angular selectivity of the monochromatic volume holographic grating, the brightness of the coupled-out image is too low to meet the brightness requirement of the augmented reality display device for the output image, so the coupling-in/coupling-out device of the volume holographic waveguide in this embodiment is formed by stacking two composite volume holographic gratings. The structure can effectively reuse the lost 0-level diffraction light, improve the lighting effect, realize pupil expansion, ensure the continuity and integrity of the final image and improve the light and shade stripes of the displayed image.

In this embodiment, the volume holographic slab waveguide set includes a three-layer volume holographic slab waveguide, and the wavelength selectivity of the volume holographic grating is utilized to perform diffraction transmission on red light, green light and blue light separately and couple out the red light, the green light and the blue light to the human eye for imaging, so as to reduce the chromatic dispersion and crosstalk of similar chromatic light. Each layer holographic slab waveguide includes a tunable attenuator, an incoupling/outcoupling volume holographic grating, and a slab waveguide. The adjustable attenuation sheet and the incoupling volume holographic grating are positioned on the same side of the slab waveguide and are respectively attached to the upper surface and the lower surface of the slab waveguide, and the adjustable attenuation sheet is used for adjusting the incident light intensity so that the final coupled light intensity of R, G, B three-color light is uniform and consistent.

For example, as shown in fig. 3, (a) and (b) in fig. 3 are for clearly showing the labeled content, so the label is split. The volume holographicslab waveguide group 3 comprises three layers of overlapped volume holographic slab waveguides, namely a first volumeholographic slab waveguide 31, a second volumeholographic slab waveguide 32 and a third volumeholographic slab waveguide 33; the incoupling volumeholographic grating 313 of the first volumeholographic slab waveguide 31 diffracts only red light; the incoupling volumeholographic grating 323 of the second volumeholographic slab waveguide 32 diffracts only green light; the incoupling volumeholographic grating 333 of the third volumeholographic slab waveguide 33 diffracts only blue light. The in-coupling volumeholographic gratings 313, 323, 333 and the out-coupling volumeholographic gratings 314, 324, 334 each comprise two identical reflective volume holographic gratings that are compositely stacked on each other. Wherein the first in-coupling volumeholographic grating 313 includes two identical reflective volume holographic gratings 313C1 and 313C2 that are compositely stacked with each other, it is understood that the first out-coupling volumeholographic grating 314 includes 314D1 and 314D2, the second in-coupling volumeholographic grating 323 includes 323C1 and 323C2, the second out-coupling volumeholographic grating 324 includes 324D1 and 324D2, the third in-coupling volumeholographic grating 333 includes 333C1 and 333C2, and the third out-coupling volumeholographic grating 334 includes 334D1 and334D 2. The in-coupling volumeholographic gratings 313, 323, 333 are mirror symmetric to the out-coupling volumeholographic gratings 314, 324, 334, respectively. The material of thewaveguide plates 312, 322, 332 is transparent optical glass or transparent optical plastic.

The in-couplingvolume hologram gratings 313, 323, and 333 and the out-couplingvolume hologram gratings 314, 324, and 334 are multiplexed volume hologram gratings manufactured based on an angle multiplexing technique. The volume holographic grating waveguide with the two-piece composite volume holographic grating stacked structure can effectively reuse 0-order diffraction light lost by the fact that the first layer of grating 313C1 of the first incoupling volume holographic grating at the coupling end directly transmits out of the waveguide, so that the 0-order diffraction light is diffracted at the second layer of grating 313C2 of the first incoupling volume holographic grating and enters the waveguide, and the light efficiency is improved. Meanwhile, at the coupling-out end, the first layer grating 314D1 of the first coupling-out body holographic grating and the second layer grating 314D2 of the first coupling-out body holographic grating can simultaneously couple out the transmission light, so that the propagation period of the light in the optical waveguide is increased, the pupil gap of each field of view light is eliminated, pupil expansion is realized, the continuity and the integrity of the final image are ensured, and the light and dark stripes of the displayed image can be improved.

The diffraction image light which is emitted by the optical-mechanical system and carries the image information of the three-dimensional color virtual object vertically enters the first layer of grating 313C1 of the first incoupling volume holographic grating at the coupling end of the first volume holographic flat waveguide through the firstadjustable attenuation sheet 311, only the negative first-order diffraction light of red light is coupled into the optical waveguide due to the wavelength selectivity of the volume holographic grating, the 0-order diffraction light of the red light is vertically incident into the second layer of grating 313C2 of the first incoupling volume holographic grating and then is diffracted, and the negative first-order diffraction light of the diffraction light is also coupled into the optical waveguide.

When the total reflection condition is satisfied, the two coupled-in diffracted lights can propagate forwards in the optical waveguide in a total reflection manner to the coupled-out volumeholographic grating 314 at the coupled-out end of the first integrated holographic slab waveguide for diffraction coupling. At the coupling-out end, the first layer grating 314D1 of the first coupling-out body holographic grating and the second layer grating 314D2 of the first coupling-out body holographic grating can simultaneously couple out the transmission light, so that the propagation period of the light in the optical waveguide is increased, the pupil gap of each field of view light is eliminated, the pupil expansion is realized, the continuity and the integrity of the final image are ensured, and the bright and dark stripes of the displayed image can be improved.

Then, the diffracted image light which is filtered to remove the red light and carries the image information of the three-dimensional colorful virtual object vertically enters the first layer of grating 323C1 of the second incoupling volume holographic grating at the coupling end of the second volume holographic slab waveguide through the secondadjustable attenuation sheet 321, only the negative first-order diffracted light of the green light is coupled into the optical waveguide due to the wavelength selectivity of the volume holographic grating, the 0-order diffracted light of the green light is vertically incident to the second layer of grating 323C2 of the second incoupling volume holographic grating and is diffracted, and the negative first-order diffracted light of the diffracted light is also coupled into the optical waveguide. When the total reflection condition is satisfied, the two coupled-in diffracted lights can propagate forward in the optical waveguide by total reflection to the coupled-out volumeholographic grating 324 at the coupling-out end of the second volume holographic slab waveguide for diffraction coupling.

Similarly, the diffracted image light with the three-dimensional color virtual object image information, from which the red light and the green light are filtered, is vertically incident to the first grating 333C1 of the third incoupling volume holographic grating at the coupling end of the third volume holographic slab waveguide through the third adjustable attenuator 331, only the negative first-order diffracted light of the blue light is coupled into the optical waveguide due to the wavelength selectivity of the volume holographic grating, while the 0-order diffracted light of the blue light is vertically incident to the second grating 333C2 of the third incoupling volume holographic grating and is diffracted, and the negative first-order diffracted light of the diffracted light is also coupled into the optical waveguide. When the total reflection condition is satisfied, the two coupled-in diffracted lights can be propagated forward in the optical waveguide in a total reflection manner to the coupled-out volumeholographic grating 334 at the coupled-out end of the third volume holographic slab waveguide for diffraction coupling. And finally, three beams of monochromatic coupled-out diffraction light enter human eyes for imaging to form a full-color image, the full-color three-dimensional virtual object image can be observed at the human eyes, and the ambient light enters the human eyes for imaging through the coupling-out device and the waveguide sheet without being influenced.

The utility model provides a pair of near-to-eye device of compact augmented reality utilizes the characteristics that self-luminous LCoS module provides the output light and the low-power consumption of high brightness, designs the little display optical system of small and exquisite, high efficiency, reduces the volume and the weight of component by a wide margin, reduces the system size and makes the structure more compact simultaneously, is fit for the human body and wears. Meanwhile, the multiplexing volume holographic grating manufactured based on the angle multiplexing technology is used as a light coupling-in/coupling-out device to acquire three-dimensional virtual object image information at a multi-angle channel, so that the dynamic range observed by human eyes is increased, and the view field is expanded. On the other hand, because current display device adopts the compound type body holographic grating waveguide of individual layer to propagate the colour image, there is close chromatic light to crosstalk serious problem, then the utility model discloses a multilayer monochromatic body holographic grating waveguide transmits R, G, B three-color light respectively for solve close chromatic light and crosstalk serious problem. And the embodiment of the utility model provides an in volume holographic waveguide's coupling in/coupling out device adopts two compound volume holographic grating to pile up and constitutes, can effectively reuse the 0 th order diffraction light that the loss falls when propagating the color image to improve the light efficiency, can solve among the prior art because the angle selectivity of monochromatic volume holographic grating, the luminance of coupling out image is low excessively, is difficult to satisfy the technical problem of augmented reality display device to the luminance demand of output image. Meanwhile, pupil expansion can be realized, the continuity and the integrity of the final image are ensured, and the purpose of displaying light and shade stripes of the image is improved.

The foregoing is a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, a plurality of improvements and decorations can be made without departing from the principle of the present invention, and these improvements and decorations are also considered as the protection scope of the present invention.

Claims (9)

1. A compact augmented reality near-to-eye device is characterized by comprising an LCoS module, an optical machine system and a volume holographic slab waveguide set;

the incidence surface of the optical-mechanical system is parallel to the emergent surface of the LCoS module, and the optical-mechanical system is used for receiving the light emergent from the LCoS module;

the emergent surface of the optical-mechanical system is adjacent to the upper surface of the volume holographic slab waveguide group, and the optical-mechanical system is used for converting the light emitted by the LCoS module into polarized light and then emitting the polarized light to the volume holographic slab waveguide group;

the volume holographic slab waveguide group comprises a plurality of layer volume holographic slab waveguides, and each volume holographic slab waveguide comprises an adjustable attenuation sheet, an in-coupling volume holographic grating, an out-coupling volume holographic grating and a waveguide plate; the adjustable attenuation sheet is arranged on the upper surface of the waveguide plate and is positioned at the coupling end of the volume holographic slab waveguide; the coupling-in body holographic grating and the coupling-out body holographic grating are arranged on the lower surface of the waveguide plate and are respectively positioned at the coupling-in end and the coupling-out end of the body holographic slab waveguide;

and the volume holographic flat waveguide group is used for diffracting and transmitting the polarized light and coupling out for imaging.

2. The compact augmented reality near-eye device of claim 1 further comprising an LED light source comprising R, G and a B tristimulus light source, and a controller for controlling the LED light source to rapidly time-share light R, G and the B tristimulus light source to achieve color illumination.

3. The compact augmented reality near-eye device of claim 1,

the optical-mechanical system comprises a beam splitter prism, a polarizing plate, a first half wave plate, a first quarter wave plate, a concave mirror, a second quarter wave plate, a convex mirror and a second half wave plate;

the polaroid, the concave mirror, the convex mirror and the second half-wave plate are respectively arranged on different end face sides of the beam splitter in parallel; the first half-wave plate is arranged between the polaroid and the beam splitter prism; the first quarter-wave plate is arranged between the concave mirror and the beam splitter prism; the second quarter-wave plate is arranged between the convex mirror and the beam splitter prism; the second half-wave plate is arranged between the volume holographic slab waveguide group and the beam splitter prism.

4. The compact augmented reality near-eye device of claim 3,

the first end surface of the light splitting prism parallel to the polaroid is parallel to the adjustable attenuation sheet of the volume holographic slab waveguide group;

the beam splitting prism is parallel to the second end face of the first quarter-wave plate, is parallel to the third end face of the second quarter-wave plate, and is perpendicular to the first end face.

5. The compact augmented reality near-eye device of claim 1, wherein the set of volume holographic slab waveguides comprises three overlapping layers of volume holographic slab waveguides, a first volume holographic slab waveguide, a second volume holographic slab waveguide, and a third volume holographic slab waveguide;

the incoupling volume holographic grating of the first volume holographic slab waveguide diffracts only red light; the incoupling volume holographic grating of the second volume holographic slab waveguide diffracts only green light; the incoupling volume holographic grating of the third volume holographic slab waveguide diffracts only blue light.

6. The compact augmented reality near-eye device of claim 1, wherein the in-coupling volume holographic grating and the out-coupling volume holographic grating each comprise two identical reflective volume holographic gratings that are compositely stacked with each other.

7. The compact augmented reality near-eye device of claim 1, wherein the in-coupling volume holographic grating and the out-coupling volume holographic grating are mirror symmetric.

8. The compact augmented reality near-eye device of claim 1, wherein the material of the waveguide plate is transparent optical glass or transparent optical plastic.

9. The compact augmented reality near-eye device of any one of claims 1-8, wherein the in-coupling volume holographic grating and the out-coupling volume holographic grating are multiplexed volume holographic gratings fabricated based on an angular multiplexing technique.

Images