CN113848648A - Optical transmission system and display device - Google Patents
Optical transmission system and display device Download PDFInfo
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- CN113848648A CN113848648A CN202111124204.2A CN202111124204A CN113848648A CN 113848648 A CN113848648 A CN 113848648A CN 202111124204 A CN202111124204 A CN 202111124204A CN 113848648 A CN113848648 A CN 113848648A
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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 present disclosure provides an optical transmission system and a display device, the optical transmission system is used for transmitting collimated image light, an angle range of the image light incident to the optical transmission system is divided into a plurality of angle sections, the optical transmission system includes: the grating light source comprises an optical waveguide, a plurality of coupling-in gratings and a plurality of coupling-out gratings, wherein the coupling-in gratings and the coupling-out gratings are arranged on the surface of the optical waveguide, have corresponding relations, and have different coupling-out gratings corresponding to different coupling-in gratings; each coupling grating is used for coupling the image light in the corresponding angle interval into the light guide; the optical waveguide is used for enabling the image light rays coupled into the optical waveguide to generate total reflection; the light coupling grating is used for coupling image light coupled in by the corresponding light coupling grating out of the optical waveguide, and the angle intervals corresponding to different light coupling gratings are different. The technical scheme can improve the brightness uniformity in the whole view field range and improve the visual watching experience of a user.
Description
Technical Field
The present disclosure relates to the field of optical technologies, and in particular, to an optical transmission system and a display device.
Background
Augmented Reality (AR) technology is a technology for skillfully fusing virtual information and a real world, and virtual information such as characters, images, three-dimensional models, music, videos and the like generated by a computer is applied to the real world after being simulated, and the two kinds of information are mutually supplemented, so that the real world is enhanced.
The current augmented reality display device generally comprises an image source and an optical transmission system, wherein image light rays emitted by the image source are transmitted to human eyes through the optical transmission system. In the related art, the diffractive optical waveguide sheet is adopted as a main structure of the optical transmission system, and finally, the uniformity of the brightness of the displayed image is poor.
Disclosure of Invention
The present disclosure provides an optical transmission system and a display device to improve brightness uniformity of a displayed image.
The present disclosure provides an optical transmission system for transmitting collimated image light, an angle range of the image light incident to the optical transmission system is divided into a plurality of angle sections, the optical transmission system includes:
the grating light source comprises an optical waveguide, a plurality of coupling-in gratings and a plurality of coupling-out gratings, wherein the coupling-in gratings and the coupling-out gratings are arranged on the surface of the optical waveguide, have corresponding relations, and have different coupling-out gratings corresponding to different coupling-in gratings;
each coupling grating is used for coupling image light in a corresponding angle interval into the optical waveguide; the optical waveguide is used for enabling the image light rays coupled into the optical waveguide to generate total reflection; the light coupling grating is used for coupling image light coupled in by the corresponding light coupling grating out of the optical waveguide, and the angle intervals corresponding to different light coupling gratings are different.
In an alternative implementation manner, the number of the optical waveguides is multiple, and the optical waveguides are stacked along a first direction;
the optical waveguide comprises an optical waveguide, an incoupling grating and an outcoupling grating, wherein the incoupling grating and the outcoupling grating which have corresponding relations are arranged on two surfaces of the same optical waveguide, which are opposite to each other in a first direction, and are respectively close to two end faces of the same optical waveguide, which are opposite to each other in a second direction, and the second direction is perpendicular to the first direction.
In an optional implementation manner, the plurality of optical waveguides includes a first optical waveguide and a second optical waveguide, the plurality of incoupling gratings includes a first incoupling grating and a second incoupling grating, and the plurality of outcoupling gratings includes a first outcoupling grating and a second outcoupling grating;
the first coupling-in grating and the first coupling-out grating have a corresponding relation and are arranged on the surface of the first optical waveguide; the second coupling-in grating and the second coupling-out grating have a corresponding relation and are both arranged on the surface of the second optical waveguide.
In an optional implementation manner, if the incoupling grating is a reflective grating, the incoupling grating is located on a side of the optical waveguide where the incoupling grating is away from the image light incident;
if the incoupling grating is a transmission grating, the incoupling grating is located on the side of the optical waveguide where the image light is incident.
In an optional implementation manner, if the coupling-out grating is a reflective grating, the coupling-out grating is located on a side of the optical waveguide where the coupling-out grating deviates from the incident side of the image light;
and if the coupling-out grating is a transmission grating, the coupling-out grating is positioned on one side of the optical waveguide, which is close to the incidence of the image light.
In an alternative implementation manner, orthographic projections of the coupled-in optical gratings on the optical waveguides respectively completely overlap; and/or the orthographic projections of the coupled gratings on the optical waveguide completely overlap.
In an alternative implementation manner, the diffraction orders of the image light diffracted by the incoupling grating and the outcoupling grating which have corresponding relations are the same.
In an alternative implementation, the grating periods of the in-grating and the out-grating having the corresponding relationship are the same.
In an alternative implementation, the duty cycle of the in-coupling grating and/or the out-coupling grating is greater than or equal to 0.4 and less than or equal to 0.6.
In an alternative implementation, the incoupling grating is a surface relief grating or a volume holographic grating; and/or the coupling-out grating is a surface relief grating or a volume holographic grating.
In an alternative implementation, the intervals of the angle intervals are equal in size and do not overlap with each other.
In an optional implementation manner, when image light in the angle range is incident to a plane where the corresponding incoupling grating is located, an overlapping area is formed, and the corresponding incoupling grating covers the overlapping area.
The present disclosure provides a display device including: a display panel, a collimating lens, and any of the optical transmission systems;
the display panel is used for emitting image light rays for displaying images to the collimating lens;
the collimating lens is used for collimating the image light and transmitting the collimated image light to the incoupling grating.
In an alternative implementation manner, the light rays emitted by the display panel, the collimating lens and the coupling grating are located on the same side of the optical transmission system.
In an alternative implementation, the display panel is a monochrome micro-OLED display panel.
Compared with the prior art, the present disclosure includes the following advantages:
according to the optical transmission system and the display device, the field angle of the image light is divided into a plurality of angle sections, the image light in each angle section is respectively coupled into and coupled out through a group of coupling-in grating and a group of coupling-out grating, finally, the image light coupled out by the plurality of coupling-out gratings is superposed, namely, the image light is seen by human eyes, through optimizing the parameters of the coupling-in gratings and the coupling-out gratings, the brightness uniformity in the whole field range can be improved, and the visual viewing experience of a user is improved.
The foregoing description is only an overview of the technical solutions of the present disclosure, and the embodiments of the present disclosure are described below in order to make the technical means of the present disclosure more clearly understood and to make the above and other objects, features, and advantages of the present disclosure more clearly understandable.
Drawings
In order to more clearly illustrate the embodiments of the present disclosure or technical solutions in related arts, the drawings used in the description of the embodiments or related arts will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present disclosure, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts. It should be noted that the scale in the drawings is merely schematic and does not represent actual scale.
Fig. 1 schematically shows a structural view of a diffractive light waveguide in the related art;
FIG. 2 is a schematic diagram showing diffraction efficiency versus field angle;
FIG. 3 schematically illustrates a structural schematic of an optical transmission system;
fig. 4 schematically shows a structural view of another optical transmission system;
FIG. 5 is a graph schematically illustrating diffraction efficiency versus field angle for a plurality of coupled-out gratings;
FIG. 6 is a schematic cross-sectional view of a surface relief grating;
FIG. 7 is a graph schematically illustrating diffraction efficiency versus grating duty cycle for each diffraction order;
fig. 8 schematically shows a structural diagram of a display device.
Detailed Description
To make the objects, technical solutions and advantages of the embodiments of the present disclosure more clear, the technical solutions of the embodiments of the present disclosure will be described clearly and completely with reference to the drawings in the embodiments of the present disclosure, and it is obvious that the described embodiments are some, but not all embodiments of the present disclosure. All other embodiments, which can be derived by a person skilled in the art from the embodiments disclosed herein without making any creative effort, shall fall within the protection scope of the present disclosure.
Augmented reality display devices are generally composed of an image source and an optical transmission system, and image light emitted from the image source is transmitted to human eyes through the optical transmission system. In the related art, a diffractive optical waveguide sheet is generally used as a main structure of an optical transmission system, and as shown in fig. 1, the diffractive optical waveguide sheet mainly includes three parts, i.e., an incoupling grating, a plate glass, and an outcoupling grating. The image light emitted by the image source is diffracted by the coupling grating in the entrance pupil area, the diffracted light enters the plate glass for total reflection, and then the diffracted light enters human eyes by the coupling grating in the exit pupil area to complete the transmission of the image picture.
The inventors found that, since the diffraction efficiency of the diffraction grating is related to the size of the field angle when image light is transmitted in the entire field angle range by using the single diffractive light waveguide sheet, as shown in fig. 2, the diffraction efficiency is high in the central field of view of 0 °, and the diffraction efficiency is lower as the distance from the edge of the field of view is closer, so that the effect that the brightness of the central field of view is high, the brightness of the edge field of view is low, and the brightness in the field of view is uneven when the human eye observes at the exit pupil position is clearly felt.
In order to improve the uniformity of the brightness of the field of view of the displayed image, an embodiment of the present disclosure provides an optical transmission system for transmitting collimated image light, wherein the angle at which the image light is incident on the optical transmission system is divided into a plurality of angle sections.
In practical applications, as shown in fig. 8, the image light may be parallel light emitted from the display panel 81 to the collimating lens 82 and collimated by the collimating lens 82. The angle range (hereinafter referred to as a field angle) in which the collimated parallel light rays are incident on the optical transmission system 83 is formed by a plurality of angle sections.
The structural schematic diagrams of two optical transmission systems are respectively schematically shown with reference to fig. 3 and 4. As shown in fig. 3 and 4, the optical transmission system includes:
the optical waveguide 31, the plurality of coupling-in gratings 32 and the plurality of coupling-out gratings 33 are arranged on the surface of the optical waveguide 31, the coupling-in gratings 32 and the coupling-out gratings 33 have corresponding relations, and the coupling-out gratings 33 corresponding to different coupling-in gratings 32 are different.
Each of the in-coupling gratings 32 is configured to couple image light in a corresponding angle interval into the optical waveguide 31; the optical waveguide 31 is used for generating total reflection of the image light coupled therein; the coupling-out grating 33 is used for coupling image light coupled in by the corresponding coupling-in grating 32 out of the optical waveguide 31, and the corresponding angle intervals of different coupling-in gratings 32 are different.
In this embodiment, the incoupling grating 32 may be disposed on a side surface of the light waveguide 31 close to the image light incidence side, or on a side surface of the light waveguide 31 away from the image light incidence side, which is not limited in this embodiment.
In this embodiment, the coupling-out grating 33 may be disposed on a surface of the optical waveguide 31 near the image light incidence side, or on a surface of the optical waveguide 31 away from the image light incidence side, which is not limited in this embodiment.
As shown in fig. 8, a surface of the optical waveguide 31 on a side where the image light is incident, that is, a surface of the optical waveguide 31 on a side where the collimating lens 82 or the display panel 81 is adjacent, and a surface of the optical waveguide 31 on a side where the image light is incident, that is, a surface of the optical waveguide 31 on a side where the collimating lens 82 or the display panel 81 is away.
The coupling-out grating 33 differs for different coupling-in gratings 32. Specifically, as shown in fig. 3 and 4, the plurality of in-coupling gratings 32 may include, for example, a first in-coupling grating 321, a second in-coupling grating 322, and the like, and the plurality of out-coupling gratings 33 may include, for example, a first out-coupling grating 331, a second out-coupling grating 332, and the like, wherein the first in-coupling grating 321 and the first out-coupling grating 331 have a corresponding relationship, and the second in-coupling grating 322 and the second out-coupling grating 332 have a corresponding relationship.
In the present embodiment, for each image light coupled into the optical waveguide 31 by the incoupling grating 32, the optical waveguide 31 is coupled out by the outcoupling grating 33 corresponding to the incoupling grating 32.
The different incoupling gratings 32 couple image light into the light guide 31 at different angular intervals. For each incoupling grating 32, the angular interval of the image curve of the incoupling grating 32 in the incoupling waveguide 31 may be the same as the angular interval of the image light of the outcoupling waveguide 31 of the outcoupling grating 33 corresponding to the incoupling grating 32.
The technical solution provided by the present embodiment is described below by taking an example that the field angle of the image light incident on the optical transmission system is divided into a first angle interval and a second angle interval, the plurality of incoupling gratings 32 includes a first incoupling grating 321 and a second incoupling grating 322, and the plurality of outcoupling gratings 33 includes a first outcoupling grating 331 and a second outcoupling grating 332.
As shown in fig. 3 and 4, the first incoupling grating 321 is used for coupling the image light in the first angle interval into the optical waveguide 31, after the image light in the first angle interval is diffracted by the first incoupling grating 321, an angle at which the diffracted light enters the surface of the optical waveguide 31 satisfies a total reflection condition, and can be totally reflected in the optical waveguide 31, and finally, the diffracted light is diffracted out of the optical transmission system by the first incoupling grating 331 corresponding to the first incoupling grating 321, and an angle range of the diffracted image light can be the first angle interval.
As shown in fig. 3 and 4, the second incoupling grating 322 is used for incoupling the image light in the second angle interval into the optical waveguide 31, after the image light in the second angle interval is diffracted by the second incoupling grating 322, the angle at which the diffracted light enters the surface of the optical waveguide 31 satisfies the total reflection condition, and the image light can be totally reflected in the optical waveguide 31, and finally diffracted out of the optical transmission system by the second incoupling grating 332 corresponding to the second incoupling grating 322, and the angle range of the diffracted image light can be the second angle interval.
It should be noted that the diffracted light of the image light outside the first angle interval after being diffracted by the first incoupling grating 321 may not satisfy the condition of total reflection in the optical waveguide 31. The diffracted light of the image light outside the second angle interval, which is diffracted by the second incoupling grating 322, may not satisfy the condition of total reflection in the optical waveguide 31.
In this embodiment, the intervals of the plurality of angle intervals may be equal or unequal, and this embodiment does not limit this. For example, the field angle of the image rays may be-20 ° to 20 °, -25 ° to 25 °, or-10 ° to 20 °, etc. When the angle of view is-25 ° to 25 °, the angle of view may be divided into two equal angle sections of-25 ° to 0 ° and 0 ° to 25 °, or two unequal angle sections of-25 ° to 5 ° and 5 ° to 25 °, and so on.
In specific implementation, the angle intervals can be mutually non-overlapped, so that the final output image of the optical transmission system is free from ghost images, and the brightness uniformity of the display image is further improved.
The brightness of the image light exiting from the coupling-out grating 33 will be described below by taking as an example a field angle at which the image light enters the optical transmission system of-20 ° to 20 °, which is divided on average into a first angle interval of-20 ° to 0 °, and a second angle interval of 0 ° to 20 °.
The first incoupling grating 321 and the first outcoupling grating 331 act on image light within a first angle interval, and a central field angle of the outcoupled light is-10 degrees from the center of the first angle interval; the second incoupling grating 322 and the second outcoupling grating 332 act on the image light in the second angle interval, and the central field angle of the outcoupled light is 10 ° from the center of the second angle interval.
Fig. 5 is a graph schematically showing diffraction efficiency versus field angle after division into angle segments. As shown in fig. 5, curve 1 corresponds to the diffraction efficiency of the first outcoupling grating 331, and can represent the brightness distribution of the image light exiting from the first outcoupling grating 331; curve 2, corresponding to the diffraction efficiency of the second outcoupling grating 332, may represent the brightness distribution of the image light exiting from the second outcoupling grating 33. The brightness of the image finally seen by human eyes is the superposition of the image light rays emitted from the first outcoupling grating 331 and the second outcoupling grating 332, as shown in curve 3 in fig. 5, and it can be seen that the uniformity of the brightness of the image after superposition in the whole field of view is obviously improved. The field angle range of the image light finally emitted by the optical transmission system may coincide with the field angle range of the image light incident to the image transmission system.
In the optical transmission system provided by this embodiment, the field angle of the image light is divided into a plurality of angle sections, the image light in each angle section is coupled into and out of the optical waveguide 31 by one set of the coupling-in grating 32 and the coupling-out grating 33, and finally the image light coupled out by the plurality of coupling-out gratings 33 is superimposed, that is, an image seen by human eyes, and by optimizing the parameters of each coupling-in grating 32 and coupling-out grating 33, the brightness uniformity in the whole field range can be improved, and the visual viewing experience of a user is improved.
In this embodiment, the coupling-in grating 32 may be a surface relief grating or a volume holographic grating, which is not limited in this embodiment.
In this embodiment, the coupling-out grating 33 may be a surface relief grating or a volume holographic grating, which is not limited in this embodiment.
In practical applications, a total reflection critical angle at which the image light propagates in the optical waveguide 31 can be determined according to the refractive index of the optical waveguide 31, and according to the total reflection critical angle and an angle interval of the parallel image light emitted to the incoupling grating 32, grating parameters of the incoupling grating 32 can be designed, so that the image light in the angle interval passes through the incoupling grating 32 to form diffracted light emitted to the optical waveguide 31, and incident angles of the diffracted light emitted to the surface of the optical waveguide 31 are all greater than the total reflection critical angle.
For each in-coupling grating 32, the incident angle of the image light to the in-coupling grating 32 within the angle range corresponding to the in-coupling grating 32, the diffraction angle after diffraction by the in-coupling grating 32, the grating parameters of the in-coupling grating 32, and the wavelength of the image light satisfy the grating equation, and thus, the grating parameters of each in-coupling grating 32 can be determined according to the grating equation.
Wherein the grating parameters may include at least one of: refractive index, duty cycle, grating height, tilt angle, grating period, and the like.
The grating periods of the incoupling grating 32 and the outcoupling grating 33 having the corresponding relationship may be the same, which is not limited in this embodiment.
By optimally designing parameters such as duty ratio, grating height, inclination angle and the like of the coupling-in grating and the coupling-out grating, the diffraction efficiency of the grating can be improved. Referring to fig. 6, a schematic cross-sectional structure of a surface relief grating is shown. Optionally, the material of the grating may be Tio2Where the refractive index n1 of the grating substrate is 1.7, the gap refractive index n2 is 1, the grating height h may be 294nm, and the grating inclination angle θ may be 40.7 °.
As shown in fig. 6, the duty cycle of the grating is the ratio of the grating width a to the grating period d. Alternatively, the duty cycle of the incoupling grating 32 may be greater than or equal to 0.4 and less than or equal to 0.6. The duty cycle of the outcoupling grating 33 may be greater than or equal to 0.4 and less than or equal to 0.6. A graph of diffraction efficiency versus grating duty cycle for each diffraction order is schematically illustrated with reference to fig. 7. As shown in fig. 7, when the duty ratio of the grating is 0.5, the diffraction efficiency corresponding to the-1 order is the highest, which is more than 90%.
Alternatively, the orthographic projections of the plurality of coupled-in gratings 32 on the light guide 31 may partially overlap or completely overlap, so that the number of optical components required to be arranged on the transmission path of the image light incident from the display panel 81 to the optical transmission system can be reduced, thereby saving the space, volume and weight of the whole display device and reducing the cost.
Alternatively, the orthographic projections of the plurality of coupling-out gratings 33 on the light guide 31 may partially overlap or completely overlap, so that the number of optical components required to be arranged on the transmission path of the image light from the optical transmission system to the human eye can be reduced, thereby saving the space, volume and weight of the whole display device and reducing the cost.
Optionally, when the image light in the angle range is incident on the plane where the incoupling grating 32 corresponding to the angle range is located, an overlapping area is formed, and the incoupling grating 32 corresponding to the angle range covers the overlapping area. Specifically, the image light in the angle range is incident on the incoupling grating 32 corresponding to the angle range, the image light at each angle in the angle range forms an overlapping region on the plane where the corresponding incoupling grating 32 is located, and when the corresponding incoupling grating 32 covers the overlapping region, the image light at each angle in the angle range can be received, so that the human eyes can see a complete image in the field angle range.
The diffraction orders of the image light diffracted by the coupling-in grating 32 and the coupling-out grating 33 having a corresponding relationship may be the same. For example, the diffraction orders may be all 1 st order or-1 st order, and the specific diffraction order may be determined according to the diffraction efficiency.
In the present embodiment, the number of the optical waveguides 31 may be one, as shown in fig. 3; there may be a plurality of optical waveguides 31, as shown in fig. 4, the number of optical waveguides 31 may also be two, and the number of optical waveguides 31 may also be 3, 4, 5, etc., and the present embodiment does not limit the number of optical waveguides 31.
As shown in fig. 4, when the number of the optical waveguides 31 is plural, the plural optical waveguides 31 may be stacked in the first direction. A plurality of optical waveguides 31 may be disposed at intervals. A medium having a lower refractive index than the material of the two adjacent light waveguides 31 may be filled between the two adjacent light waveguides 31, so that the image light rays may be totally internally reflected in the light waveguides 31. The medium having a lower refractive index than the material of the adjacent two optical waveguides 31 may be, for example, air or the like.
The number of the incoupling gratings 32 and the outcoupling gratings 33 can be increased by increasing the number of the light guides 31, so that the division of the angle sections can be refined, and the brightness uniformity of the display image can be further improved. In addition, by increasing the number of the incoupling gratings 32 and the outcoupling gratings 33, the color types of image light can be increased, thereby realizing the display of a color image with richer colors.
The coupling-in grating 32 and the coupling-out grating 33 which have corresponding relations are arranged on two opposite surfaces of the same optical waveguide 31 along a first direction, and are respectively arranged close to two end faces of the same optical waveguide 31, the two end faces are oppositely arranged along a second direction, and the second direction is perpendicular to the first direction.
In the present implementation, two surfaces of the optical waveguide 31 opposing in the first direction include a side surface of the optical waveguide 31 near the image light incident (i.e., a lower surface of the optical waveguide shown in fig. 4) and a side surface of the optical waveguide 31 away from the image light incident (i.e., an upper surface of the optical waveguide shown in fig. 4). The coupling-in grating 32 and the coupling-out grating 33 which have corresponding relations can be both arranged on the surface of the same optical waveguide 31 on the side close to the image light incidence, or both arranged on the surface of the same optical waveguide 31 on the side away from the image light incidence, or one of the coupling-in grating and the coupling-out grating is arranged on the surface of the same optical waveguide 31 on the side close to the image light incidence and the other coupling-out grating is arranged on the surface of the same optical waveguide 31 on the side away from the image light incidence.
As shown in fig. 3 and 4, the incoupling grating 32 may be disposed near the end surface a, and the outcoupling grating 33 having a corresponding relationship with the incoupling grating 32 may be disposed near the end surface b, both end surfaces being disposed opposite to each other along the second direction. The end face a connects a surface of the optical waveguide 31 on a side close to the image light incident and a surface of the optical waveguide 31 on a side away from the image light incident, and the end face b connects a surface of the optical waveguide 31 on a side close to the image light incident and a surface of the optical waveguide 31 on a side away from the image light incident.
If the incoupling grating 32 is a reflective grating, the incoupling grating 32 is located on the side of the light waveguide 31 where the incoupling grating 32 is located, which is away from the image light incidence side; if the incoupling grating 32 is a transmissive grating, the incoupling grating 32 is located on the side of the light guide 31 where the incoupling grating 32 is located near the incident of image light.
The optical waveguide 31 in which the incoupling grating 32 is located is the optical waveguide 31 in which the incoupling grating 32 couples image light.
If the coupling-out grating 33 is a reflective grating, the coupling-out grating 33 is located on a side of the optical waveguide 31 where the coupling-out grating 33 is located, which is away from the image light incidence side; if the coupling-out grating 33 is a transmissive grating, the coupling-out grating 33 is located on a side of the light waveguide 31 where the coupling-out grating 33 is located, which is close to the image light incident side.
The light guide 31 in which the coupling-out grating 33 is located is the light guide 31 from which the coupling-out grating 33 couples out image light.
In this implementation, each optical waveguide 31 is provided with a different incoupling grating 32 on its surface. As shown in fig. 4, the plurality of optical waveguides 31 includes a first optical waveguide 311 and a second optical waveguide 312, the plurality of incoupling gratings 32 includes a first incoupling grating 321 and a second incoupling grating 322, and the plurality of outcoupling gratings 33 includes a first outcoupling grating 331 and a second outcoupling grating 332.
The first incoupling grating 321 and the first outcoupling grating 331 have a corresponding relationship and are both disposed on the surface of the first optical waveguide 311; the second incoupling grating 322 and the second outcoupling grating 332 have a corresponding relationship and are both disposed on the surface of the second optical waveguide 312.
As shown in fig. 4, the first incoupling grating 321 is a transmissive grating and disposed on a surface of the first optical waveguide 311 near to a side where the image light is incident, and the first outcoupling grating 331 is a reflective grating and disposed on a surface of the first optical waveguide 311 away from the side where the image light is incident. The second incoupling grating 322 and the second outcoupling grating 332 are transmissive gratings, and are disposed on the surface of the second optical waveguide 312 near the image light incident side.
An embodiment of the present disclosure further provides a display device, and a schematic structural diagram of the display device is schematically shown with reference to fig. 8. As shown in fig. 8, the display device includes: a display panel 81, a collimating lens 82, and an optical transmission system 83 as provided in any of the embodiments.
Among them, the display panel 81 is used to emit image light of a display image to the collimator lens 82.
The collimating lens 82 is used to collimate the image light and transmit the collimated image light to the incoupling grating 32.
In this embodiment, the image light emitted from the display panel 81 is collimated by the collimating lens 82, and then the collimated light enters the optical transmission system 83, and then exits to the human eyes through the optical transmission system 83, thereby completing the transmission of the image frame.
In this embodiment, the image light may be a monochromatic light. Alternatively, the display panel 81 may be a monochrome micro OLED display panel 81, which is not limited in this embodiment.
In this embodiment, the collimating lens 82 may be formed by three aspheric lenses, which is not limited in this embodiment.
In an alternative implementation, the display panel 81, the collimating lens 82 and the light exiting from the coupling-out grating 33 are located on the same side of the optical transmission system 83.
The display panel 81 and the collimating lens 82 are disposed on the same side of the optical transmission system 83 as the field of view of the human eye (i.e. the side out of which the light emitted from the grating 33 is coupled), so that the display device is more suitable for the structure of glasses, wherein the display panel 81 and the collimating lens 82 can be located at the position of the glasses legs, which is convenient for preparing an augmented reality display device more suitable for the wearing habit of the user. Of course, the display panel 81 and the field of vision of human eyes may be located on the opposite side of the optical transmission system 83, and this embodiment is not limited thereto as the case may be.
The embodiments in the present specification are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other.
Finally, it should also be noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.
The optical transmission system and the display device provided by the present disclosure are described in detail above, and the principles and embodiments of the present disclosure are explained herein by applying specific examples, and the above descriptions of the examples are only used to help understanding the method and the core idea of the present disclosure; meanwhile, for a person skilled in the art, based on the idea of the present disclosure, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present disclosure should not be construed as a limitation to the present disclosure.
Other embodiments of the disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the disclosure disclosed herein. This disclosure is intended to cover any variations, uses, or adaptations of the disclosure following, in general, the principles of the disclosure and including such departures from the present disclosure as come within known or customary practice within the art to which the disclosure pertains. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the disclosure being indicated by the following claims.
It will be understood that the present disclosure is not limited to the precise arrangements described above and shown in the drawings and that various modifications and changes may be made without departing from the scope thereof. The scope of the present disclosure is limited only by the appended claims.
Reference herein to "one embodiment," "an embodiment," or "one or more embodiments" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present disclosure. Moreover, it is noted that instances of the word "in one embodiment" are not necessarily all referring to the same embodiment.
In the description provided herein, numerous specific details are set forth. However, it is understood that embodiments of the disclosure may be practiced without these specific details. In some instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.
In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word "comprising" does not exclude the presence of elements or steps not listed in a claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The disclosure may be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In the unit claims enumerating several means, several of these means may be embodied by one and the same item of hardware. The usage of the words first, second and third, etcetera do not indicate any ordering. These words may be interpreted as names.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solutions of the present disclosure, not to limit them; although the present disclosure has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present disclosure.
Claims (15)
1. An optical transmission system for transmitting collimated image light, wherein an angle range of the image light incident on the optical transmission system is divided into a plurality of angle sections, the optical transmission system comprising:
the grating light source comprises an optical waveguide, a plurality of coupling-in gratings and a plurality of coupling-out gratings, wherein the coupling-in gratings and the coupling-out gratings are arranged on the surface of the optical waveguide, have corresponding relations, and have different coupling-out gratings corresponding to different coupling-in gratings;
each coupling grating is used for coupling image light in a corresponding angle interval into the optical waveguide; the optical waveguide is used for enabling the image light rays coupled into the optical waveguide to generate total reflection; the light coupling grating is used for coupling image light coupled in by the corresponding light coupling grating out of the optical waveguide, and the angle intervals corresponding to different light coupling gratings are different.
2. The optical transmission system according to claim 1, wherein the number of the optical waveguides is plural, and a plurality of the optical waveguides are stacked along a first direction;
the optical waveguide comprises an optical waveguide, an incoupling grating and an outcoupling grating, wherein the incoupling grating and the outcoupling grating which have corresponding relations are arranged on two surfaces of the same optical waveguide, which are opposite to each other in a first direction, and are respectively close to two end faces of the same optical waveguide, which are opposite to each other in a second direction, and the second direction is perpendicular to the first direction.
3. The optical transmission system according to claim 2, wherein the plurality of optical waveguides includes a first optical waveguide and a second optical waveguide, the plurality of incoupling gratings includes a first incoupling grating and a second incoupling grating, and the plurality of outcoupling gratings includes a first outcoupling grating and a second outcoupling grating;
the first coupling-in grating and the first coupling-out grating have a corresponding relation and are arranged on the surface of the first optical waveguide; the second coupling-in grating and the second coupling-out grating have a corresponding relation and are both arranged on the surface of the second optical waveguide.
4. The optical transmission system according to claim 2, wherein if the incoupling grating is a reflective grating, the incoupling grating is located on a side of the optical waveguide that is away from the image light incident side;
if the incoupling grating is a transmission grating, the incoupling grating is located on the side of the optical waveguide where the image light is incident.
5. The optical transmission system according to claim 2, wherein if the outcoupling grating is a reflective grating, the outcoupling grating is located on a side of the optical waveguide where the light wave guide deviates from the incident side of the image light;
and if the coupling-out grating is a transmission grating, the coupling-out grating is positioned on one side of the optical waveguide, which is close to the incidence of the image light.
6. The optical transmission system according to any one of claims 1 to 5, wherein orthographic projections of the plurality of the incoupling gratings on the optical waveguides, respectively, are entirely overlapped; and/or the orthographic projections of the coupled gratings on the optical waveguide completely overlap.
7. An optical transmission system as claimed in any one of claims 1 to 5, wherein the diffraction orders of the image light diffracted by the incoupling grating and the outcoupling grating which are in corresponding relationship are the same.
8. An optical transmission system according to any one of claims 1 to 5, wherein the grating periods of the incoupling grating and the outcoupling grating having the correspondence are the same.
9. Optical transmission system according to one of claims 1 to 5, characterized in that the duty cycle of the incoupling grating and/or the outcoupling grating is greater than or equal to 0.4 and less than or equal to 0.6.
10. An optical transmission system as claimed in any one of claims 1 to 5, wherein the incoupling grating is a surface relief grating or a volume holographic grating; and/or the coupling-out grating is a surface relief grating or a volume holographic grating.
11. The optical transmission system according to any one of claims 1 to 5, wherein the intervals of the plurality of angle intervals are equal in size and do not overlap with each other.
12. An optical transmission system as claimed in any one of claims 1 to 5, wherein the image light rays in the angle range form an overlapping region when incident on a plane on which the corresponding incoupling grating is located, and the corresponding incoupling grating covers the overlapping region.
13. A display device, comprising: a display panel, a collimating lens, and an optical transmission system according to any one of claims 1 to 12;
the display panel is used for emitting image light rays for displaying images to the collimating lens;
the collimating lens is used for collimating the image light and transmitting the collimated image light to the incoupling grating.
14. The display device of claim 13, wherein the light exiting the display panel, the collimating lens, and the outcoupling grating are located on the same side of the optical transmission system.
15. The display device according to claim 13, wherein the display panel is a monochrome micro-OLED display panel.
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| CN202111124204.2A CN113848648A (en) | 2021-09-24 | 2021-09-24 | Optical transmission system and display device |
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| CN202111124204.2A CN113848648A (en) | 2021-09-24 | 2021-09-24 | Optical transmission system and display device |
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| CN114415283A (en) * | 2022-01-11 | 2022-04-29 | 江西凤凰光学科技有限公司 | Multichannel diffraction optical waveguide device |
| CN114690428A (en) * | 2022-04-06 | 2022-07-01 | 杭州光粒科技有限公司 | Grating waveguide display system |
| CN114839779A (en) * | 2022-05-24 | 2022-08-02 | 歌尔光学科技有限公司 | Optical waveguide structure, optical module and head-mounted display equipment |
| CN116338969A (en) * | 2023-05-31 | 2023-06-27 | 杭州光粒科技有限公司 | Display module assembly and AR equipment |
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| CN110471185A (en) * | 2019-08-28 | 2019-11-19 | 瑞声通讯科技(常州)有限公司 | Waveguide augmented reality display device |
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| CN114415283A (en) * | 2022-01-11 | 2022-04-29 | 江西凤凰光学科技有限公司 | Multichannel diffraction optical waveguide device |
| CN114690428A (en) * | 2022-04-06 | 2022-07-01 | 杭州光粒科技有限公司 | Grating waveguide display system |
| CN114839779A (en) * | 2022-05-24 | 2022-08-02 | 歌尔光学科技有限公司 | Optical waveguide structure, optical module and head-mounted display equipment |
| CN114839779B (en) * | 2022-05-24 | 2023-06-30 | 歌尔光学科技有限公司 | Optical waveguide structure, optical module and head-mounted display device |
| CN116338969A (en) * | 2023-05-31 | 2023-06-27 | 杭州光粒科技有限公司 | Display module assembly and AR equipment |
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