CN211928226U - Optical waveguide lens and three-dimensional display device - Google Patents
Optical waveguide lens and three-dimensional display device Download PDFInfo
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- CN211928226U CN211928226U CN202020227413.4U CN202020227413U CN211928226U CN 211928226 U CN211928226 U CN 211928226U CN 202020227413 U CN202020227413 U CN 202020227413U CN 211928226 U CN211928226 U CN 211928226U
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Abstract
The utility model provides an optical waveguide lens and three-dimensional display device, the optical waveguide lens includes: a waveguide; and a functional region on the waveguide, the functional region including an entrance functional region, a turning functional region, and an exit functional region. The first two-dimensional array structure is arranged in the incident functional area, light is coupled into the waveguide by the first two-dimensional array structure and is coupled into the light in the waveguide, part of the light is transmitted towards the emergent functional area along the first direction, and part of the light is transmitted towards the turning functional area along the second direction; the one-dimensional grating is arranged in the turning functional area and reflects the light rays propagating towards the turning functional area back to the incident functional area; and a second two-dimensional array structure is arranged in the exit functional region and couples light rays propagating towards the turning functional region out of the waveguide. The utility model discloses can reflect back the coupling-in region with the diffraction light that deviates from the regional propagation of coupling-out, promote optical efficiency.
Description
Technical Field
The utility model relates to a display technology, concretely relates to optical waveguide lens and three-dimensional display device.
Background
Augmented Reality (AR) technology is a new technology for seamlessly integrating real world information and virtual world information, not only shows the real world information, but also simultaneously displays the virtual information, and the two kinds of information are mutually supplemented and superposed.
At present, most of the mainstream near-eye augmented reality display devices adopt the optical waveguide principle. For example, Hololens is a method for realizing color projection by coupling out an image on LCOS through three pieces of holographic gratings, transmitting the image to human eyes, and passing through an optical waveguide. In order to simplify the manufacturing process and further reduce the size of the display device, more and more researchers have tried to perform diffraction transmission by using a two-dimensional array grating, in which a coupling-in region and a coupling-out region are formed on a waveguide sheet, and the two-dimensional array grating is disposed in the coupling-in region and the coupling-out region. The incident light is incident on the coupling-in area, is transmitted to the coupling-out area through coupling-in, and finally enters human eyes through the coupling-out area, so that color projection is realized. The light rays are expanded and stretched in the interaction process of the two-dimensional array grating in the coupling-in area and the coupling-out area, so that the pupil expansion in the two-dimensional space is realized.
However, this solution of diffractive guiding using a two-dimensional array grating has the following significant drawbacks: after the light is incident on the coupling-in area, due to the diffraction characteristics of the two-dimensional array grating, the incident light is split into a plurality of beams of diffracted light, wherein only a small part of the diffracted light is transmitted towards the coupling-out area, and most of the diffracted light is transmitted away from the coupling-out area and is lost. Thus, the light efficiency of the display device is low, and the imaging effect is not good enough.
In view of this, there is a need to improve the existing two-dimensional array grating diffraction transmission scheme to transmit as much diffracted light as possible to the coupling-out region, so as to improve the light efficiency and enhance the imaging effect.
SUMMERY OF THE UTILITY MODEL
In order to achieve the above technical object, the first aspect of the present invention provides an optical waveguide lens, which can reflect the part of the diffracted light beams departing from the coupling-out region to the coupling-in region, thereby improving the optical efficiency and enhancing the imaging effect. The detailed technical scheme of the utility model is as follows:
an optical waveguide lens, comprising:
a waveguide;
a functional region having an optical diffraction function on an upper surface or a lower surface of the waveguide, the functional region including an incident functional region, a turning functional region, and an exit functional region, wherein:
a first two-dimensional array structure is arranged in the incident functional area and is configured to couple light into the waveguide and into the light in the waveguide, wherein part of the light propagates towards the emergent functional area along a first direction and part of the light propagates towards the turning functional area along a second direction;
a one-dimensional grating is arranged in the turning functional area and is configured to reflect the light rays propagating towards the turning functional area along the second direction back to the incident functional area;
a second two-dimensional array structure is disposed within the exit functional region, the second two-dimensional array structure being configured to couple the light propagating along the second direction toward the turning functional region out of the waveguide.
In some embodiments, the turning functional region comprises a first turning functional region and a second turning functional region symmetrically disposed on both sides of the incident functional region.
In some embodiments, the Littrow condition is satisfied between the light ray propagating along the second direction toward the turning functional region and the one-dimensional grating disposed in the turning functional region. The one-dimensional grating is a holographic grating, a blazed grating or a rectangular grating.
In some embodiments, the one-dimensional grating is a blazed grating, and an incident angle of the light propagating in the second direction towards the turning functional region matches a scintillation angle of the blazed grating.
In some embodiments, the first and second two-dimensional array structures include cylindrical array structures, rectangular pillar array structures, and wedge-shaped pillar array structures.
In some embodiments, the first two-dimensional array structure and the second two-dimensional array structure are formed by two superimposed exposures:
fixing the positions of an exposure light source and the waveguide to complete the first exposure to obtain a one-dimensional grating structure;
the exposure light source is kept still, the waveguide rotates for a preset angle along the center, the second exposure is completed, and a two-dimensional array structure is obtained;
the exposure light source is composed of two planar light beams, and the two planar light beams form an exposure interference surface.
In some embodiments, the entrance functional area and the exit functional area are spaced apart.
In some embodiments, the entrance functional region and the exit functional region are integrally formed.
In some embodiments, the waveguide has a refractive index greater than 1.4 and a thickness of no more than 2 mm.
In some embodiments, the first two-dimensional array structure and the second two-dimensional array structure are two-dimensional array structures with the same structure, the grating period of the two-dimensional array structure is 200nm to 600nm, the grating depth is 50nm to 600nm, and an included angle between two grating orientations of the two-dimensional array structure is 90 ° to 160 °.
The utility model discloses the second aspect provides a three-dimensional display device, it includes:
a micro-projection device for generating image light;
an optical waveguide lens, the optical waveguide lens is any one of the optical waveguide lens of the first aspect of the present invention.
Compared with the prior art, the utility model discloses a set up the functional region of turn, can deviate from the diffraction light reflection back coupling-in region that the coupling-out region propagated with the part to promote optical efficiency, promote the formation of image effect.
Drawings
Fig. 1 is a schematic structural diagram of an optical waveguide lens according to the present invention;
fig. 2 is a schematic diagram of the optical path of the optical waveguide lens according to the present invention;
FIG. 3 is a schematic diagram of the optical path of a light ray in an incident functional area;
FIG. 4 is a schematic diagram of the light path of a light ray in a turning functional region;
fig. 5 is a grating orientation diagram of the two-dimensional array structure of the present invention.
Detailed Description
To further illustrate the technical means and effects of the present invention adopted to achieve the objectives of the present invention, the following detailed description will be made in conjunction with the accompanying drawings and preferred embodiments for the specific embodiments, structures, features and effects of the head-up display system and the automobile according to the present invention as follows:
the foregoing and other technical and other features and advantages of the invention will be apparent from the following detailed description of preferred embodiments, which proceeds with reference to the accompanying drawings. While the present invention has been described with reference to the embodiments, the drawings are for illustrative purposes only and are not intended to limit the present invention.
Fig. 1 is a schematic structural diagram of the optical waveguide lens of the present invention, which is used as a display screen of an augmented reality display device. As shown in fig. 1, the optical waveguide lens includes:
a waveguide 1;
functional regions having an optical diffraction function are provided on the upper surface or the lower surface of the waveguide 1, and as shown in fig. 1, if one surface on which image light is incident and emitted is defined as the upper surface, in the embodiment of fig. 1, each functional region is provided on the upper surface of the waveguide 1.
The functional regions include an incident functional region 2, a turning functional region 4, and an exit functional region 3, wherein:
a first two-dimensional array structure is arranged within the incident functional area, the first two-dimensional array structure being configured to couple light into the waveguide 1. Of the light rays coupled into the waveguide 1, part of the light rays propagate in a first direction towards the exit functional region 3 and part of the light rays propagate in a second direction towards the turning functional region 4.
A one-dimensional grating is arranged within the turning functional region 4, the one-dimensional grating being configured to reflect light rays propagating in the second direction towards the turning functional region 4 back into the incident functional region 3.
A second two-dimensional array structure is arranged within the exit functional region 3, the second two-dimensional array structure being configured to couple light rays propagating along a second direction towards the turning functional region 4 out of the waveguide 1.
The optical principle of the multi-directional diffractive extended optical waveguide lens of the present invention will be described below, and in between, we define the following coordinate axes:
an X axis: the width direction of the waveguide 1 is also the direction of the binocular connecting line of the user;
y-axis: the height direction of the waveguide 1 is also the extension direction of the nose bridge of the user;
z-axis: perpendicular (or orthogonal) to the X-Y plane defined by the X-axis and Y-axis.
It can be seen that the incident functional region 2, the turning functional region 4 and the exit functional region 3 of the present invention are located on the X-Y plane.
The utility model discloses diffraction structure in well incident functional region 2 and the functional region 3 of outgoing is two-dimensional array structure.
As shown in fig. 2 and 3, when an incident light beam of image light emitted from the micro-projection device is incident on the incident functional area 2 along the Z-axis, the image light and the first two-dimensional array structure in the incident functional area 2 generate and interact to form multiple 1 st-order and-1 st-order diffracted lights, wherein: the diffracted light meeting the total reflection condition of the waveguide 1 is conducted in the waveguide 1 in a total reflection form, in the total reflection process, the light repeatedly returns to the waveguide 1 for multiple times and generates new interaction with the first two-dimensional array structure, and multiple paths of diffracted light are formed in each interaction process, wherein: part of the light forms a reflective diffraction while changing the azimuth angle and is guided in the first direction (the direction towards the exit functional area 3) towards the exit functional area 3, while part of the light continues to be guided in the original direction at the angle of total reflection.
Furthermore, during each interaction, a part of the diffracted light propagates in the second direction (away from the exit functional area 3) towards the turning functional area 4. After the part of light enters the turning functional region 4, the part of light interacts with the one-dimensional grating in the turning functional region 4 to generate 180-degree deflection so as to return to the incident functional region 2. The process can at least achieve the following technical effects: the diffraction light that will deviate from the regional 3 propagation of outgoing functionality reflects back into the functional region 2 of incidence to increased the total amount of the light that enters into the regional 3 of outgoing functionality, reduced the loss of image light, promoted optical efficiency, finally strengthened the imaging effect.
In order to realize that the light incident on the turning functional region 4 can return to the incident functional region 2 to the maximum extent, the light efficiency is further improved. As shown in fig. 4, by adaptively setting the grating structure of the one-dimensional grating in the turning functional region 4, the Littrow (Littrow) condition is satisfied between the light incident to the one-dimensional grating and the one-dimensional grating, that is: the incident light and the first-order diffraction light generated by the diffraction of the one-dimensional grating are in an auto-collimation state, so that the following effects are achieved: the first order diffracted light can be deflected by 180 ° along the incident path of the incident light and returned to the incident functional region 2.
The Littrow conditions are well known to those of ordinary skill in the art and can be characterized by the following equation: theta1＝sin-1(λ/(2 ×) in which: lambda is the wavelength of incident light, lambda is the grating period, theta1Is the angle of incidence of the incident light.
Therefore, in the embodiment of the present invention, only the grating structure of the one-dimensional grating needs to be adaptively set according to the wavelength and the incident angle of the light incident to the turning functional region 4, and the Littrow (Littrow) condition can be satisfied between the light incident to the turning functional region 4 and the one-dimensional grating.
The one-dimensional grating may be a holographic grating, a blazed grating or a rectangular grating. As an alternative solution, the one-dimensional grating in the turning functional region 4 is arranged as a blazed grating, the angle of incidence of the light propagating in the second direction towards the turning functional region 4 matching the blaze angle of the blazed grating.
With continued reference to fig. 1 and 2, in order to capture as much diffracted light as possible away from the exit functional area 3. Preferably, the turning functional region 4 includes a first turning functional region 41 and a second turning functional region 42 symmetrically disposed at both sides of the incident functional region 2.
When the image light guided from the incident functional area 2 reaches the exit functional area 3 along the waveguide 1, the light interacts with the second two-dimensional array structure in the exit functional area 3 and forms diffracted light in multiple directions, wherein: and part of the diffracted light is diffracted out of the emergent functional area 3 along the Z axis and observed, part of the diffracted light is conducted in the waveguide 1 in a total reflection mode, in the total reflection process, the light repeatedly returns to the emergent functional area 3 for multiple times and generates new interaction with the second two-dimensional array structure, the diffracted light in multiple directions is formed in each interaction process, part of the light is diffracted out of the emergent functional area 3 along the Z axis and observed, and part of the light continues to propagate and expand.
It can be seen that, through interaction with the second two-dimensional array structure, the image light guided from the incident functional region 2 can not only be coupled out of the waveguide 1 to achieve imaging, but also, in the course of multiple interactions with the second two-dimensional array structure, the image light can be expanded and stretched to further expand the field-of-view image and the visible region.
Because, in the utility model discloses in, image light can be coupled out to each mutual point homoenergetic of second two-dimensional array structure in the functional region 3 of outgoing, consequently, clear image can all be seen to the human eye in whole functional region 3 of outgoing.
At this stage, various one-dimensional gratings and two-dimensional arrays of gratings are typically fabricated on the waveguide using an interferometric exposure process, as is well known to those skilled in the art. In some embodiments, the first two-dimensional array structure and the second two-dimensional array structure are formed by two times of overlapping exposures of the single light beam set, and each exposure of the single light beam set corresponds to a group of structures. Specifically, the two times of single beam group superposition exposure are as follows:
fixing the positions of an exposure light source and the waveguide to complete the first exposure to obtain a one-dimensional grating structure;
the exposure light source is kept still, the waveguide rotates for a preset angle along the center, the second exposure is completed, and a two-dimensional array structure is obtained;
the exposure light source is composed of two planar waves, and the two planar waves form an exposure interference surface.
Wherein: the predetermined angle of rotation of the waveguide about the center corresponds to the angle between the two grating orientations of the finally formed two-dimensional array structure. If the target orientation angle of the two grating orientations of the two-dimensional array structure to be formed is 90 deg., then the predetermined angle is 90 deg..
In other embodiments, the first two-dimensional array structure and the second two-dimensional array structure are formed by exposing each of the first two-dimensional array structure and the second two-dimensional array structure at one time in order to improve the production efficiency. In these embodiments, the exposure light source is constituted by four plane waves, each of which forms an exposure interference surface, and the two exposure interference surfaces are oriented at a predetermined angle with respect to each other.
In some embodiments, the first two-dimensional array structure and the second two-dimensional array structure have the same structure, the grating period is 200 nm-600 nm, and the grating depth is 50 nm-600 nm. The first two-dimensional array structure and the second two-dimensional array structure may be a cylindrical array structure, a rectangular pillar array structure, a wedge-shaped pillar array structure, or the like.
In some embodiments, as shown in FIG. 5, the angle a between the two grating orientations of the two-dimensional array structure is 90 to 160.
Because the utility model discloses an in some embodiments, the structure of first two-dimensional array structure and second two-dimensional array structure sets up to the exact same, consequently, in order to improve production efficiency, can be with the regional 2 disposable shaping of incidence functional and the regional 3 of emergence functional indiscriminately.
Of course, the entrance functional region 2 and the exit functional region 3 may be provided separately. I.e. there is a smooth waveguide between the entrance functional area 2 and the exit functional area 3 without any diffractive array structure on it. The arrangement can improve the optical efficiency of a human eye viewing area and avoid unnecessary diffraction attenuation.
Further, in some embodiments of the present invention, the waveguide 1 is a glass waveguide having high transmittance, a refractive index greater than 1.4, and a thickness not exceeding 2 mm.
The utility model also provides a three-dimensional display device, it includes: a micro-projection device for generating image light; optical waveguide lens, this optical waveguide lens adopt the utility model discloses the optical waveguide lens that any above-mentioned embodiment provided.
The invention has been described above with a certain degree of particularity and detail. It will be understood by those of ordinary skill in the art that the description of the embodiments is merely exemplary and that all changes that may be made without departing from the true spirit and scope of the present invention are intended to be within the scope of the present invention. The scope of the invention is defined by the appended claims rather than by the foregoing description of the embodiments.
Claims (11)
1. An optical waveguide lens, comprising:
a waveguide;
a functional region having an optical diffraction function on an upper surface or a lower surface of the waveguide, the functional region including an incident functional region, a turning functional region, and an exit functional region, wherein:
a first two-dimensional array structure is disposed within the incident functional area, the first two-dimensional array structure being configured to couple light into the waveguide, into light within the waveguide: part of the light rays propagate towards the exit functional region along a first direction, and part of the light rays propagate towards the turning functional region along a second direction;
a one-dimensional grating is arranged in the turning functional area and is configured to reflect the light rays propagating towards the turning functional area along the second direction back to the incident functional area;
a second two-dimensional array structure is disposed within the exit functional region, the second two-dimensional array structure being configured to couple the light propagating along the second direction toward the turning functional region out of the waveguide.
2. The optical waveguide lens of claim 1 wherein the turning functional region comprises a first turning functional region and a second turning functional region symmetrically disposed on opposite sides of the incident functional region.
3. The optical waveguide lens of claim 1, wherein a Littrow condition is satisfied between the light propagating along the second direction toward the turning functional region and the one-dimensional grating disposed in the turning functional region.
4. The optical waveguide lens of claim 3 wherein the one-dimensional grating is a holographic grating, a blazed grating, or a rectangular grating.
5. The optical waveguide lens according to claim 3, wherein the one-dimensional grating is a blazed grating, and an angle between the light ray propagating in the second direction toward the turning functional region and a normal line of a grating surface of the blazed grating is equal to a blazed angle of the blazed grating.
6. The optical waveguide lens of claim 1 wherein the first two-dimensional array structure and the second two-dimensional array structure comprise a cylindrical array structure, a rectangular pillar array structure, and a wedge-shaped pillar array structure.
7. The optical waveguide lens of claim 1 wherein the entrance functional area and the exit functional area are spaced apart.
8. The optical waveguide lens of claim 1 wherein the entrance functional region and the exit functional region are integrally formed.
9. The optical waveguide lens of claim 1 wherein the waveguide has a refractive index greater than 1.4 and a thickness of no more than 2 mm.
10. The optical waveguide lens of claim 1, wherein the first two-dimensional array structure and the second two-dimensional array structure are two-dimensional array structures with the same structure, the grating period of the two-dimensional array structure is 200nm to 600nm, the grating depth is 50nm to 600nm, and the included angle between two grating orientations of the two-dimensional array structure is 90 ° to 160 °.
11. A three-dimensional display device, characterized by: it includes:
a micro-projection device for generating image light;
an optical waveguide lens according to any one of claims 1 to 10.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113433621A (en) * | 2021-06-24 | 2021-09-24 | 北京枭龙科技有限公司 | High-efficiency grating waveguide element |
| CN113777703A (en) * | 2021-08-25 | 2021-12-10 | 宁波舜宇奥来技术有限公司 | Optical waveguide structure and near-eye display |
| CN115453678B (en) * | 2022-01-30 | 2023-08-29 | 珠海莫界科技有限公司 | Optical combiner and display device |
-
2020
- 2020-02-28 CN CN202020227413.4U patent/CN211928226U/en active Active
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113433621A (en) * | 2021-06-24 | 2021-09-24 | 北京枭龙科技有限公司 | High-efficiency grating waveguide element |
| CN113777703A (en) * | 2021-08-25 | 2021-12-10 | 宁波舜宇奥来技术有限公司 | Optical waveguide structure and near-eye display |
| CN113777703B (en) * | 2021-08-25 | 2024-06-04 | 宁波舜宇奥来技术有限公司 | Optical waveguide structure and near-to-eye display |
| CN115453678B (en) * | 2022-01-30 | 2023-08-29 | 珠海莫界科技有限公司 | Optical combiner and display device |
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