CN111323920B - Diffraction light waveguide for AR display - Google Patents
Diffraction light waveguide for AR display Download PDFInfo
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- CN111323920B CN111323920B CN202010169030.0A CN202010169030A CN111323920B CN 111323920 B CN111323920 B CN 111323920B CN 202010169030 A CN202010169030 A CN 202010169030A CN 111323920 B CN111323920 B CN 111323920B
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- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/01—Head-up displays
- G02B27/017—Head mounted
- G02B27/0172—Head mounted characterised by optical features
Abstract
The invention relates to the technical field of optical imaging systems, in particular to a novel diffraction light waveguide for AR display, which comprises a waveguide main body, wherein a pupil expansion exit pupil area for expanding a pupil and an exit pupil of light rays containing image information is arranged on the waveguide main body, an entrance pupil area is arranged at the position close to the center of the pupil expansion exit pupil area, the image information is guided into the pupil expansion exit pupil area through the entrance pupil area, and an upper recovery area, a lower recovery area and a left recovery area and a right recovery area are arranged at the periphery of the pupil expansion exit pupil area and are used for recovering the light rays emitted from the pupil expansion exit pupil area to the periphery. The optical waveguide can recover energy to improve the overall efficiency of the optical waveguide, and can greatly solve the problem of image uniformity.
Description
Technical Field
The invention relates to the technical field of optical imaging systems, in particular to a diffraction light waveguide for AR display.
Background
The near-eye display technology is one of the key technologies that must be used in current AR glasses. The near-eye display system generally comprises an image source and an optical transmission system, wherein image pictures sent by the image source are transmitted to human eyes through the optical transmission system. The optical transmission system needs to have a certain transmittance, so that the wearer can see the external environment while seeing the image.
For optical transmission systems, there are many schemes in the industry, such as free space optics, free form optics, and display light guides. The optical waveguide technology is obviously superior to other optical schemes due to the characteristic of large eye movement range and the light and thin characteristic, and becomes a mainstream path of each large company.
However, the existing optical waveguide system has the following problems: 1. the system optical efficiency of the optical waveguide is low; 2. some optical waveguide systems reduce the brightness uniformity of an image when the eyebox is enlarged, resulting in uneven color of the image; 3. some optical waveguide systems cannot realize two-dimensional pupil expansion and have large volumes.
Disclosure of Invention
To overcome the above-mentioned drawbacks of the prior art, the present invention provides a diffractive light waveguide for AR display to solve the problems set forth in the background art.
The technical scheme adopted by the invention for solving the problems in the prior art is as follows: the utility model provides a diffraction light waveguide that AR shows, includes the waveguide main part, be equipped with in the waveguide main part and be used for carrying out the diffusion pupil exit pupil region of diffusion pupil and exit pupil with the light that includes image information the position that the center of diffusion pupil exit pupil region leaned on is equipped with into the pupil region, and image information is inside diffusion pupil exit pupil region through the introduction into of diffusion pupil region, diffusion pupil exit pupil region is equipped with all around and is used for retrieving from diffusion pupil exit pupil region to the upper and lower recovery region and control the recovery region of light of launching all around.
In a preferred embodiment of the present invention, the waveguide body is a transmission body of a waveguide made of flat glass.
In a preferred embodiment of the present invention, the upper and lower recovery regions include a first upper recovery region and a second upper recovery region which are vertically arranged above the pupil exit region, and a first lower recovery region and a second lower recovery region which are vertically arranged below the pupil exit region, and the first upper recovery region and the first lower recovery region are provided at positions close to the pupil exit region.
As a preferable aspect of the present invention, the left and right collecting regions include a left collecting region provided on the left side of the pupil exit region and a right collecting region provided on the right side of the pupil exit region.
As a preferred embodiment of the present invention, in the distribution of the entrance pupil region, the exit pupil region, the upper and lower recovery regions, and the left and right recovery regions in k-space, the total reflection wave vectors of the entrance pupil region and the exit pupil region directly pass through the center of the circle to reach the position of circular symmetry, and the upper and lower recovery regions and the left and right recovery regions may adopt a vertical reflection mode or a discrete oblique reflection mode.
As a preferable aspect of the present invention, the first upper recovery area and the second upper recovery area bypass the entrance pupil area by using a left-right separate reflection manner, the first lower recovery area and the second lower recovery area may use a vertical upward reflection manner or a left-right separate oblique reflection manner, the left-right recovery area may use a direct reflection manner toward the center or a right-oblique upward reflection manner, and the total reflection vectors reflected upward by the left-right recovery areas directly pass through the center of a circle to reach the position of circular symmetry.
As a preferred embodiment of the present invention, the entrance pupil region employs a tilted grating or a binary grating.
In a preferred embodiment of the present invention, the exit pupil area of the pupil is a two-dimensional grating.
In a preferred embodiment of the present invention, the upper and lower recovery regions and the left and right recovery regions are tilted gratings or binary gratings.
As a preferable scheme of the invention, the waveguide main body adopts special glass, resin, plastic and the like with the refractive index of 1.4-2.45 and the thickness range of 0.1-1.5 mm, and the waveguide main body adopts binary grating, blazed grating, two-dimensional grating and inclined grating with the grating period of 10-1000 nm, the height range of 10-3000 nm and the duty ratio range of 90-5%.
Compared with the prior art, the invention has the following technical effects:
according to the diffraction light waveguide for AR display, the upper recovery area, the lower recovery area, the left recovery area and the right recovery area are arranged, energy is recovered, the overall efficiency of the optical waveguide is improved, meanwhile, light reflected by the recovery areas is gradually attenuated, the attenuation directions are opposite, the light is overlapped with original emergent light rays, and the problem of image uniformity is greatly solved.
Drawings
FIG. 1 is a block diagram of a diffractive light waveguide of an AR display of the present invention;
FIG. 2 is a schematic structural diagram of a first embodiment of a diffractive optical waveguide for an AR display in accordance with the present invention;
FIG. 3 is a diagram of k-space propagation for one embodiment of a diffractive optical waveguide for an AR display according to the present invention;
FIG. 4 is a schematic structural diagram of a second embodiment of a diffractive optical waveguide for an AR display in accordance with the present invention;
FIG. 5 is a diagram of k-space propagation of a second embodiment of a diffractive optical waveguide for AR display according to the present invention.
Reference numbers in the figures: 100. an image source; 101. an entrance pupil region; 102. a pupil exit region; 103. a first upper recovery zone; 104. a second upper recovery zone; 105. a left recovery area and a right recovery area; 106. a first lower recovery area; 107. a second lower recovery zone; 108. a waveguide body; 109. the human eye.
Detailed Description
The following further describes embodiments of the present invention with reference to the drawings. It should be noted that the description of the embodiments is provided to help understanding of the present invention, but the present invention is not limited thereto. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.
As shown in figure 1: a diffraction light waveguide for AR display comprises a waveguide body 108, wherein a pupil expanding and exiting area 102 for expanding a pupil and an exiting pupil of light containing image information is arranged on the waveguide body 108, an entrance pupil area 101 is arranged at the position close to the center of the pupil expanding and exiting area 102, the entrance pupil area 101 is embedded in the pupil expanding and exiting area 102, specifically, the waveguide body 108 adopts plate glass as a transmission body of the waveguide, the light containing the image information and emitted by an image source 100 is guided into the waveguide body 108 from the entrance pupil area 101, due to the total reflection principle of the glass, the light is bound in the glass to be transmitted, when the light reaches the pupil expanding and exiting area 102, the light expands the pupil and the exiting pupil, a part of the light after the pupil expansion and the exiting pupil continues to be diffused up and down and left and right, and the other part of the light directly enters a human eye 109 through the exiting pupil.
Further, in order to recover the light energy wasted to the surrounding of the waveguide body 108 by total reflection, an upper and lower recovery region and a left and right recovery region 105 for recovering the light emitted from the pupil exit pupil region 102 to the surrounding are provided around the pupil exit pupil region 102, and specifically, the upper and lower recovery regions include a first upper recovery region 103 and a second upper recovery region 104 which are provided above and below the pupil exit pupil region 102, and a first lower recovery region 106 and a second lower recovery region 107 which are provided above and below the pupil exit pupil region 102, the first upper recovery region 103 and the first lower recovery region 106 are provided at a position close to the pupil exit pupil region 102, the left and right recovery region 105 includes a left recovery region provided at the left side of the pupil exit pupil region 102 and a right recovery region provided at the right side of the pupil exit pupil region 102, and the light totally reflected from the surrounding is provided, the light bounces back into the pupil-expanding exit pupil region 102 by the first upper recovery region 103, the second upper recovery region 104, the first lower recovery region 106, the second lower recovery region 107, the left recovery region, and the right recovery region, and the pupil-expanding and exit pupils are performed again.
Further, the upper and lower recycling areas and the left and right recycling areas can adopt a vertical reflection mode or a separated oblique reflection mode. Specifically, the first upper recovery area and the second upper recovery area adopt a left-right discrete reflection mode to enable the first upper recovery area and the second upper recovery area to bypass the entrance pupil area, the first lower recovery area and the second lower recovery area can adopt a vertical upward reflection mode or a left-right discrete oblique reflection mode, and the left-right recovery area can adopt a direct central reflection mode or an oblique upward reflection mode.
Preferably, the entrance pupil region 101 employs a tilted grating or a binary grating.
Preferably, the pupil exit pupil region 102 employs a two-dimensional grating.
Preferably, the upper and lower recovery regions and the left and right recovery regions 105 employ a slanted grating or a binary grating.
Preferably, the waveguide main body 108 is made of special glass, resin, plastic and the like with a refractive index of 1.4-2.45 and a thickness range of 0.1-1.5 mm, and the waveguide main body 108 is made of binary grating, blazed grating, two-dimensional grating and inclined grating with a grating period of 10-1000 nm, a height range of 10-3000 nm and a duty ratio range of 90-5%.
In this embodiment, an incident wavelength of an incident light ray is defined as λ, the first upper recovery region 103 and the second upper recovery region 104 use a tilted grating or a binary grating, wave vectors of the gratings are k3 and k4, grating periods are λ/k3 and λ/k4, the left recovery region and the right recovery region use a tilted grating or a binary grating, wave vectors of the gratings are k5, grating periods are λ/k5, the first lower recovery region 106 and the second lower recovery region 107 use a tilted grating or a binary grating, wave vectors of the gratings are k6 and k7, and grating periods are λ/k6 and λ/k7, respectively.
In embodiment 1, the diffractive light waveguide is a surface relief grating, and the travel path pattern of different functional regions of the grating in k-space is shown in the figure, fig. 2 is a distribution diagram of the grating, and fig. 3 is a propagation pattern diagram in k-space. The incident light expressed as a rectangular box 0 in k-space is defined in the propagation pattern diagram of k-space, and after being diffracted by the grating of the entrance pupil region 101 of fig. 2, is distributed as a rectangular box 1 and a rectangular box 1 ', and the rectangular box 1' represent +1 and-1 order diffraction, respectively. The +1 order diffraction enters the pupil exit pupil region 102, the two-dimensional grating is adopted in the pupil exit pupil region 102, the rectangular frame 0 is diffracted into the two rectangular frames 2 of the pupil exit pupil region 102, but the two-dimensional grating is also diffracted back into the rectangular frame 0, so the directions of the wave vectors of the grating in the pupil exit pupil region 102 are the directions of the rectangular frame 1 and the rectangular frame 2 in fig. 3, the function of transmitting the exit pupil while transmitting the exit pupil is realized, and meanwhile, the rectangular frame 0, the rectangular frame 1 and the rectangular frame 2 form an equilateral triangle.
The functions of the first upper recovery region 103 and the second upper recovery region 104 are to diffract energy back into the exit pupil region 102 of the pupil by the grating and to bypass the entrance pupil region 101 in a left-right separated manner, and from the distribution of k-space in fig. 3, it is found that in order to recover the energy of the upper rectangular frame 1 ', the first upper recovery region 103 and the second upper recovery region 104 are designed, the energy of the rectangular frame 1 ' is reflected downward into the two rectangular frames 2, and in order not to be directly reflected back into the rectangular frame 0, it is necessary to follow the directions of k3 and k4, so the grating wave vector directions of the first upper recovery region 103 and the second upper recovery region 104 are the directions of k3 and k4, and the sizes of k3 and k4 are the lengths of the line segments from the rectangular 1 ' to the center of the rectangular frame 2.
The left and right recovery regions function to diffract energy back into the pupil exit pupil region 102 by the grating, and as is found from the k-space distribution of fig. 3, the left and right recovery regions are designed on both sides of the pupil exit pupil region 102, the energy in the rectangular frame 2 is reflected from one side into the rectangular frame 2 on the other side, the grating vector directions of the left and right recovery regions are k5 and k5 ', and the magnitudes of k5 and k 5' are the lengths of the line segments between the centers of the two rectangles 2.
The first lower recovery region 106 and the second lower recovery region 107 function to diffract energy back into the pupil exit pupil region 102 by a grating, and as is apparent from the k-space distribution of fig. 3, the first lower recovery region 106 and the second lower recovery region 107 are designed below the pupil exit pupil region 102, the first lower recovery region 106 function to reflect energy in the rectangular frame 1 into the rectangular frame 1 ', the grating wave vector direction of the first lower recovery region 106 is k6, and the size of k6 is the length of a line segment from the rectangular frame 1 to the center of the rectangular frame 1'. The second lower recovery region 107 functions to reflect the energy in the rectangular frame 2 into the rectangular frame 2 ', the direction of the grating wave vector of the second lower recovery region 107 is k7, and the size of k7 is the length of a line segment from the rectangular frame 2 to the center of the rectangular frame 2'. It should be noted that if the positions of the first lower recovery area 106 and the second lower recovery area 107 are reversed, the efficiency of energy recovery is affected.
In embodiment 2, in order to further improve the system efficiency and the brightness uniformity, some improvements may be made to the left recycling area, the right recycling area, the first lower recycling area 106 and the second lower recycling area 107, and it should be noted that the improvements may be performed separately and do not affect each other. Specifically, as shown in fig. 4, the left recovery region and the right recovery region function to diffract energy back into the pupil exit pupil region 102 through the grating, and the direction has an upward component, so that uniformity and efficiency are improved. It is found from the k-space distribution of fig. 5 that left and right recovery regions can be designed at the side of the pupil exit pupil region 102, the energy in the rectangular frame 2 is reflected from one side to the rectangular frame 2 ' at the other side, the central line of the rectangular frame 2 and the rectangular frame 2 ' passes through the center of the circle, the grating wave vector directions of the left and right recovery regions are k5 and k5 ', and the magnitudes of k5 and k5 ' are the lengths of the line segments between the centers of the rectangular frame 2 and the rectangular frame 2 '. The left and right k5 and k 5' are axisymmetric with respect to the center of the circle.
As shown in fig. 4, the first lower recovery regions 106 and the second lower recovery regions 107 function to diffract energy back into the pupil exit pupil region 102 by the grating, and wind the energy in a left-right separated manner while having components spreading to the left and right sides, thereby improving uniformity and efficiency, and it is found from the distribution of k-space in fig. 5 that the first lower recovery regions 106 and the second lower recovery regions 107 can be designed on the sides of the pupil exit pupil region 102, the first lower recovery regions 106 function to reflect energy in the rectangular frame 1 into two rectangular frames 2 ', the grating wave vector directions of the first lower recovery regions 106 and the second lower recovery regions 107 are k6, and the directions of the two k6 are shown in fig. 5, and the rectangular frame 1 points to the two rectangular frames 2'. The size is the length of the line segment from the center of the rectangular frame 1 to the center of the rectangular frame 2'. It should be noted that the positions of the first lower recovery area 106 and the second lower recovery area 107 may be reversed.
Compared with the prior art, the invention has the following technical effects:
according to the diffraction light waveguide for AR display, the upper recovery area, the lower recovery area, the left recovery area and the right recovery area 105 are arranged, energy is recovered, the overall efficiency of the optical waveguide is improved, meanwhile, light reflected by the recovery areas is gradually attenuated, the attenuation directions are opposite, the light is overlapped with original emergent light rays, and the problem of image uniformity is greatly solved.
Finally, it should be noted that: although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that changes may be made in the embodiments and/or equivalents thereof without departing from the spirit and scope of the invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (7)
1. A diffractive light waveguide for AR display, characterized by: the waveguide comprises a waveguide body, wherein a pupil-expanding exit pupil area used for expanding a pupil and an exit pupil of light rays containing image information is arranged on the waveguide body, an entrance pupil area is arranged at the position close to the center of the pupil-expanding exit pupil area, the image information is guided into the pupil-expanding exit pupil area through the entrance pupil area, and an upper recovery area, a lower recovery area, a left recovery area and a right recovery area which are used for recovering the light rays emitted from the pupil-expanding exit pupil area to the periphery are arranged at the periphery of the pupil-expanding exit pupil area;
the upper and lower recovery areas comprise a first upper recovery area and a second upper recovery area which are arranged above and below the exit pupil area of the pupil, and a first lower recovery area and a second lower recovery area which are arranged above and below the exit pupil area of the pupil, wherein the first upper recovery area and the first lower recovery area are arranged at the positions close to the exit pupil area of the pupil;
in the distribution of the entrance pupil region, the expanded pupil exit pupil region, the upper and lower recovery regions and the left and right recovery regions in the k space, the total reflection wave vectors of the entrance pupil region and the expanded pupil exit pupil region directly pass through the circle center to reach the circularly symmetric position, and the upper and lower recovery regions and the left and right recovery regions can adopt a vertical reflection mode or a discrete oblique reflection mode;
the first upper recovery area and the second upper recovery area bypass the entrance pupil area in a left-right discrete reflection mode, the first lower recovery area and the second lower recovery area can adopt a vertical upward reflection mode or a left-right discrete oblique reflection mode, the left-right recovery area can adopt a direct central reflection mode or an oblique upper reflection mode, and total reflection vectors reflected upwards by the left-right recovery area directly penetrate through the circle center to reach the position of circular symmetry.
2. The diffractive light waveguide for an AR display according to claim 1, wherein: the waveguide body is a transmission body taking plate glass as a waveguide.
3. The diffractive light waveguide for an AR display according to claim 1, wherein: the left and right recovery regions comprise a left recovery region arranged on the left side of the exit pupil region of the expanding pupil and a right recovery region arranged on the right side of the exit pupil region of the expanding pupil.
4. The diffractive light waveguide for an AR display according to claim 1, wherein: the entrance pupil area adopts an inclined grating or a binary grating.
5. The diffractive light waveguide for an AR display according to claim 1, wherein: and the exit pupil area of the expanding pupil adopts a two-dimensional grating.
6. The diffractive light waveguide for an AR display according to claim 1, wherein: the upper and lower recovery regions and the left and right recovery regions adopt tilted gratings or binary gratings.
7. The diffractive light waveguide for an AR display according to claim 2, wherein: the waveguide main body is made of special glass, resin or plastic with the refractive index of 1.4-2.45 and the thickness range of 0.1-1.5 mm, and is made of binary grating, blazed grating, two-dimensional grating or inclined grating with the grating period of 10-1000 nm, the height range of 10-3000 nm and the duty ratio range of 90-5%.
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| CN202010169030.0A CN111323920B (en) | 2020-03-12 | 2020-03-12 | Diffraction light waveguide for AR display |
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| CN202010169030.0A CN111323920B (en) | 2020-03-12 | 2020-03-12 | Diffraction light waveguide for AR display |
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| CN112180589B (en) * | 2020-09-18 | 2021-08-27 | 深圳市光舟半导体技术有限公司 | Optical pupil expanding device, display equipment thereof and method for outputting light and displaying image |
| CN113189777B (en) * | 2021-04-25 | 2021-12-14 | 深圳市光舟半导体技术有限公司 | Binocular AR eyepiece vision correction system |
| CN113433622A (en) * | 2021-06-24 | 2021-09-24 | 北京枭龙科技有限公司 | High light efficiency grating waveguide element |
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| GB2529003B (en) * | 2014-08-03 | 2020-08-26 | Wave Optics Ltd | Optical device |
| CN107329261B (en) * | 2017-06-08 | 2019-04-30 | 东南大学 | A kind of head-mounted display part based on holographical wave guide |
| CN109239920A (en) * | 2017-07-11 | 2019-01-18 | 苏州苏大维格光电科技股份有限公司 | A kind of holographical wave guide eyeglass and augmented reality display device |
| CN108681067A (en) * | 2018-05-16 | 2018-10-19 | 上海鲲游光电科技有限公司 | A kind of waveguide display device at extended field of view angle |
| CN110764261B (en) * | 2019-09-18 | 2022-03-11 | 深圳市光舟半导体技术有限公司 | Optical waveguide structure, AR equipment optical imaging system and AR equipment |
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