CN214335370U - Waveguide display structure for realizing uniform light emission - Google Patents
Waveguide display structure for realizing uniform light emission Download PDFInfo
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- CN214335370U CN214335370U CN202120563355.7U CN202120563355U CN214335370U CN 214335370 U CN214335370 U CN 214335370U CN 202120563355 U CN202120563355 U CN 202120563355U CN 214335370 U CN214335370 U CN 214335370U
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Abstract
The utility model relates to a realize waveguide display structure of even light-emitting. The utility model discloses a miniature projector, collimation system, coupling grating, planar waveguide base plate and coupling grating. The coupled-out grating is composed of a plurality of subdivided grating regions with the same period, and the thicknesses of the subdivided grating regions are gradually increased, so that the coupling efficiency of the subdivided grating regions is in an increasing trend. The utility model discloses the grating subdivision that will couple out the region is the little grating region of N to according to grating thickness and grating coupling efficiency's relation, control every grating coupling efficiency that couples out the region through changing grating thickness, and according to the regional position in grating, the regional coupling efficiency of every grating is the crescent trend, thereby reaches the effect of even light-emitting.
Description
Technical Field
The utility model relates to a waveguide display structure specifically is a waveguide display structure who realizes even light-emitting.
Background
Augmented Reality (AR) is a brand new technology for superimposing virtual image information generated by a computer on a real scene, and by using the technology, an external real scene can be seen, and a virtual image can also be seen, so that a visual effect of combining virtuality and Reality is provided for people. With the continuous development of the augmented reality technology, the AR technology is applied to various industries including military, medical health, industrial production, education and other fields, and certainly with the continuous improvement of the living standard of people, the AR technology gradually moves to the life.
At present, most of AR glasses on the market adopt a waveguide display technology, and an important problem is that the waveguide display technology couples totally reflected light inside a waveguide into human eyes through a coupling element.
In the prior art, a plurality of arrayed waveguides are usually adopted in the arrayed waveguide, the unit waveguide at each position is individually designed, the transmittance and the reflectance of each waveguide unit are designed, and each waveguide unit is coated with a film layer with different reflectances, so that the light intensity from each waveguide unit is finally consistent. In the holographic grating optical waveguide display technology, a gradient grating is usually adopted, and in a certain direction, under the condition that a grating vector is kept unchanged in the direction, the grating period and the grating inclination angle are continuously changed to achieve the effect of light-emitting uniformity.
In the two schemes, the film system reflection of each waveguide unit needs to be independently designed for the array waveguide, so that the manufacturing difficulty of the process is greatly increased, and the yield of the produced waveguide display equipment is too low; for the gradual change type holographic grating waveguide display device, the grating period and the inclination angle of each part also need to be designed, and when each part is exposed, the included angle of two beams of light in the holographic optical path needs to be adjusted in time, and meanwhile, the grating period of each part needs to be changed, so that the exposure process is greatly increased, the requirement on the exposure precision is very high, and the later-stage mass production is not facilitated.
Disclosure of Invention
In order to solve the defects of the prior art, the utility model provides a novel grating structure improves the homogeneity that the waveguide shows, after learning the relation of grating coupling efficiency and grating thickness, designs coupling part grating thickness, makes the grating light-emitting efficiency of every part unanimous, reaches the effect of even light-emitting
The utility model provides a technical scheme that technical problem took does:
the utility model comprises a micro projector, a collimation system, an in-coupling grating, a planar waveguide substrate and an out-coupling grating;
the micro projector projects the image source light generated by the computer, and the image source light is changed into parallel light to irradiate on the coupling-in grating after passing through the collimation system;
the incoupling grating changes the original transmission direction of light under the diffraction effect, so that the light is coupled into the planar waveguide substrate, and the light meeting the total reflection condition is transmitted in the planar waveguide substrate in a total reflection manner;
when the light is transmitted to the coupling-out grating of the coupling-out area, the total reflection condition is destroyed, and the light in the planar waveguide substrate is diffracted out and enters human eyes;
the coupled-out grating is composed of a plurality of subdivided grating regions with the same period, and the thicknesses of the subdivided grating regions are gradually increased, so that the coupling efficiency of the subdivided grating regions is in an increasing trend.
Further, the period is in the nanometer scale.
Furthermore, the coupling-in grating and the coupling-out grating both adopt relief gratings.
Further, the maximum thickness of the outcoupling grating is 4 μm.
Furthermore, the in-coupling grating and the out-coupling grating both adopt embossed oblique gratings.
Furthermore, the miniature projector adopts LCOS, DMO or LED.
Furthermore, the collimation system mainly comprises a lens.
The utility model has the advantages that:
the utility model discloses a to the design of coupling out relief (sculpture) grating thickness, the mode that adopts the change grating thickness reaches the effect that the coupling efficiency who changes every part realizes waveguide display system light-emitting homogeneity.
Drawings
FIG. 1 is a diagram of a waveguide display system;
FIG. 2 is a graph of grating thickness versus coupling efficiency;
FIG. 3 is a diagram illustrating coupling efficiency of each region of the grating;
FIG. 4 is a schematic structural diagram of an embodiment.
Detailed Description
The present invention will be further explained with reference to the accompanying drawings.
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the embodiments of the present invention are clearly and completely described below with reference to the drawings in the embodiments of the present invention, and the described embodiments are some embodiments of the present invention and not all embodiments.
The utility model provides a waveguide display structure for realizing uniform light emission, which comprises a micro projector, a collimation system, an in-coupling grating, a planar waveguide substrate and an out-coupling grating; the micro projector projects image source light generated by a computer, the image source light is changed into parallel light to irradiate on the coupling-in grating after passing through the collimation system, the original transmission direction of the light is changed by the coupling-in grating under the diffraction effect, the parallel light is coupled into the planar waveguide substrate, the light meeting the total reflection condition is transmitted in the planar waveguide substrate in a total reflection mode, when the light is transmitted to the grating of the coupling-out area, the total reflection condition is destroyed, and the light in the planar waveguide substrate is diffracted out of the waveguide and enters human eyes.
In the process of total reflection, in an actual situation, there is transmission loss, and a grating located at a front position couples out part of light, which results in less light continuously propagating in the waveguide, and then the grating located at a rear position also couples out less light, so that the light intensity coming out from each position is inconsistent, and the uniformity of the light output from the waveguide display system is poor.
The utility model discloses the coupling grating that uses generally refers to relief (sculpture) grating, the thickness of coupling relief (sculpture) grating sets up to the grating thickness of best coupling efficiency, and the difference of coupling relief (sculpture) grating according to the position, the thickness gradual change of relief (sculpture) grating, change grating coupling efficiency through the change to relief (sculpture) grating thickness, and be located the difference of coupling out regional position according to the grating, the coupling efficiency of grating is crescent trend, thereby compensate the inconsistent condition of luminous intensity because light loss causes.
In the present invention, the micro projection device includes some commonly used micro projectors such as LCOS, LED, DMO, etc. The collimating system mainly consists of lenses, and light projected by the projection equipment is changed into parallel beams in all directions through the lenses and is irradiated on the coupling grating.
Example (b):
as shown in fig. 1, the present embodiment mainly includes a micro projection device 1, a collimating system mainly composed of a lens 2, and a light emitted from the projection device is changed into parallel lights in various directions by the lens 2, and the light is coupled into a slab waveguide substrate 4 by an incoupling grating 3, wherein the light satisfying the total reflection condition is transmitted in the slab waveguide substrate 4 without loss, while the light not satisfying the condition directly penetrates through the slab waveguide, when the light in the waveguide substrate encounters an incoupling grating 5, the total reflection condition is destroyed, and the light is coupled out of the waveguide and enters into human eyes, the micro projection device includes some commonly used micro projectors such as LCOS, DMO, LED, etc.;
the coupling grating mainly uses relief right-angle grating and relief inclined grating, the thickness of the grating in the coupling-in area is set to be the thickness of the optimal coupling efficiency, light in the projection equipment can be enabled to be coupled into the waveguide as far as possible, in the display system, diffraction light of +/-1 order is mainly utilized, so that the relief inclined grating is selected to concentrate the light in +/-1 order, and more light is enabled to be transmitted in the waveguide in a total reflection mode.
The period of the grating in the embodiment is in a nanometer level, and the manufacturing of the relief grating can be in a micro-nano photoetching mode, an electron beam etching mode and a mask etching mode. The coupling grating 5 in this embodiment is an embossed grating, as shown in fig. 2, the embossed grating has different thicknesses of gratings at each position, that is, different coupling efficiencies corresponding to each portion, and gradually increases in a certain direction, and the thickness of the grating is selected from 0 to 4um according to the calculated thickness until the coupling efficiency of the final grating region reaches the maximum value, and it can be known from the figure that when the thickness of the grating is 4um, the maximum coupling efficiency of the grating is 90%.
As shown in fig. 3, the outcoupling grating is divided into N different grating regions, and the coupling efficiency of each grating region is reasonably set according to the position of the grating, for example, the coupling efficiency of the first outcoupling grating region is set to η%, and the grating coupling efficiency of the second region is set to (η + x)%. until the coupling efficiency of the final grating region reaches 90%, where η is the initial coupling efficiency, and x ═ is (100- η)/(N-1) an increasing coupling efficiency value, and the period of each grating is the same, so that the wavelength bands of light exiting from each grating region are consistent, and the intensity of light exiting from each part entering human eyes is consistent, so that the uniformity of the system is good.
In the embodiment shown in fig. 4, the waveguide display system is divided into three parts, i.e., an incoupling grating region, a slab waveguide region, and an outcoupling grating region. The grating structure coupled into the grating region couples light into the waveguide with maximum coupling efficiency, so that the light is transmitted by total reflection in the waveguide, and therefore the transmission angle is required to be larger than the critical angle of total reflection, while the critical angle of the slab waveguide is q ═ arcsin (1/n), where n is the refractive index of the waveguide substrate, for the display system, the waveguide substrate generally uses K9 glass with a refractive index of 1.52, the critical angle of total emission can be known to be 41.1 ° by calculation, and in the later design, the transmission angle in the waveguide is required to be larger than 41.1 °. Wherein the period of the grating is 480nm, 632nm red light is used as an incident light source, and the grating equation is as follows: Λ (sinq + sin Φ) ═ k λ, where θ and Φ are an incident angle and a diffraction angle, k is a diffraction order of the grating, since a grating period is a sub-wavelength grating, only 0 and ± 1 orders of diffracted light exist, only 1 order of diffracted light is considered herein, and when the incident angle is set to 30 °, the diffraction angle Φ calculated by a grating equation is 54.68 ° and a full emission condition is satisfied; in this embodiment, the thickness of the substrate is 10um, the total length of the coupling-out grating is 60um, in this embodiment, the coupling-out grating region is divided into three parts, the coupling efficiency of the first grating is set to 30%, the coupling efficiency of the second grating is set to 50%, and the coupling efficiency of the third grating is set to 90%, so that the light intensity of the light coming out of each part into the human eye is consistent.
To sum up, the utility model discloses a grating subdivision that will couple out the region is the little grating region of N to according to grating thickness and grating coupling efficiency's relation, control every grating coupling efficiency that couples out the region through changing grating thickness, and according to the regional position of grating, from left to right the regional coupling efficiency of every grating is the crescent trend, thereby reaches the effect of even light-emitting.
Claims (7)
1. A waveguide display structure for realizing uniform light emission comprises a micro projector, a collimation system, an incoupling grating, a planar waveguide substrate and an outcoupling grating;
the micro projector projects the image source light generated by the computer, and the image source light is changed into parallel light to irradiate on the coupling-in grating after passing through the collimation system;
the incoupling grating changes the original transmission direction of light under the diffraction effect, so that the light is coupled into the planar waveguide substrate, and the light meeting the total reflection condition is transmitted in the planar waveguide substrate in a total reflection manner;
when the light is transmitted to the coupling-out grating of the coupling-out area, the total reflection condition is destroyed, and the light in the planar waveguide substrate is diffracted out and enters human eyes;
the method is characterized in that:
the coupled-out grating is composed of a plurality of subdivided grating regions with the same period, and the thicknesses of the subdivided grating regions are gradually increased, so that the coupling efficiency of the subdivided grating regions is in an increasing trend.
2. A waveguide display structure according to claim 1, wherein: the period is in nanometer level.
3. A waveguide display structure according to claim 1, wherein: the coupling-in grating and the coupling-out grating both adopt relief gratings.
4. A waveguide display structure according to claim 3, wherein: the maximum thickness of the outcoupling grating is 4 micrometers.
5. A waveguide display structure according to claim 3 or 4 for achieving uniform light extraction, wherein: the coupling-in grating and the coupling-out grating both adopt embossed oblique gratings.
6. A waveguide display structure according to claim 1, wherein: the miniature projector adopts LCOS, DMO or LED.
7. A waveguide display structure according to claim 1, wherein: the collimation system mainly comprises a lens.
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113985616A (en) * | 2021-12-27 | 2022-01-28 | 南昌虚拟现实研究院股份有限公司 | Optical waveguide display device and augmented reality display apparatus |
| CN114690428A (en) * | 2022-04-06 | 2022-07-01 | 杭州光粒科技有限公司 | Grating waveguide display system |
| CN116381845A (en) * | 2023-06-07 | 2023-07-04 | 北京亮亮视野科技有限公司 | Coupling-in grating, diffraction grating waveguide and near-to-eye display device |
| CN117452551A (en) * | 2023-12-25 | 2024-01-26 | 上海鲲游科技有限公司 | Manufacturing method of diffraction optical waveguide |
| CN114690428B (en) * | 2022-04-06 | 2024-06-07 | 杭州光粒科技有限公司 | Grating waveguide display system |
-
2021
- 2021-03-19 CN CN202120563355.7U patent/CN214335370U/en active Active
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113985616A (en) * | 2021-12-27 | 2022-01-28 | 南昌虚拟现实研究院股份有限公司 | Optical waveguide display device and augmented reality display apparatus |
| CN114690428A (en) * | 2022-04-06 | 2022-07-01 | 杭州光粒科技有限公司 | Grating waveguide display system |
| CN114690428B (en) * | 2022-04-06 | 2024-06-07 | 杭州光粒科技有限公司 | Grating waveguide display system |
| CN116381845A (en) * | 2023-06-07 | 2023-07-04 | 北京亮亮视野科技有限公司 | Coupling-in grating, diffraction grating waveguide and near-to-eye display device |
| CN116381845B (en) * | 2023-06-07 | 2023-09-05 | 北京亮亮视野科技有限公司 | Coupling-in grating, diffraction grating waveguide and near-to-eye display device |
| CN117452551A (en) * | 2023-12-25 | 2024-01-26 | 上海鲲游科技有限公司 | Manufacturing method of diffraction optical waveguide |
| CN117452551B (en) * | 2023-12-25 | 2024-03-19 | 上海鲲游科技有限公司 | Manufacturing method of diffraction optical waveguide |
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