CN216748285U

CN216748285U - Optical waveguide module and display device

Info

Publication number: CN216748285U
Application number: CN202123137759.9U
Authority: CN
Inventors: 冯坤亮; 关赛新; 王锐
Original assignee: Jiangxi OMS Microelectronics Co Ltd
Current assignee: Jiangxi OMS Microelectronics Co Ltd
Priority date: 2021-12-14
Filing date: 2021-12-14
Publication date: 2022-06-14
Anticipated expiration: 2031-12-14

Abstract

The application provides an optical waveguide assembly and a display device. The optical waveguide component that this application provided is used for realizing the conduction of image, and the optical waveguide component of this application includes: a first waveguide for expanding the area of the exit pupil in a first dimension; and a second waveguide through which the image is transmitted to the second waveguide, the second waveguide being for expanding the area of the exit pupil in a second dimension, the second dimension intersecting the first dimension, such that the first and second waveguides expand the area of the exit pupil in a two-dimensional plane containing the first and second dimensions, the first and second waveguides being different types of waveguides. The first waveguide can enlarge the area of the exit pupil in a first dimension, and the second waveguide different from the first waveguide can enlarge the area of the exit pupil in a second dimension intersecting the first dimension, so that the optical waveguide component expands the pupil in a two-dimensional plane, the exit pupil area of an image is enlarged, and the imaging effect is better.

Description

Optical waveguide module and display device

Technical Field

The application relates to the technical field of optical devices and display, in particular to an optical waveguide component and display equipment.

Background

At present, Augmented Reality (AR) technology is used in some display devices, the AR technology is a technology for ingeniously fusing virtual information and real world information, the head-mounted display device utilizing the technology can enable people to see the surrounding environment and project virtual images to human eyes, so that the real external world and the virtual information can be seen, the virtual information and the real scene are integrated in a stacked mode, the virtual information and the real scene are mutually supplemented and enhanced, and the AR technology has important significance in the fields of military, industry, entertainment, medical treatment, transportation and the like.

The optical waveguide structure can be used for presenting virtual information, and is limited by the size of an image entrance pupil and the requirement of expanding the exit pupil of the image in order to adapt to the range of eye movement.

SUMMERY OF THE UTILITY MODEL

In view of the above problems, the present application provides an optical waveguide assembly for implementing conduction of an image, the optical waveguide assembly including:

a first waveguide for expanding the area of the exit pupil in a first dimension; and

a second waveguide through which the image is transmitted towards the second waveguide, the second waveguide being for expanding the area of the exit pupil in a second dimension that intersects the first dimension such that the first and second waveguides expand the area of the exit pupil in a two-dimensional plane containing the first and second dimensions, the first and second waveguides being of different types of waveguides.

According to the optical waveguide component, the first waveguide can enlarge the area of the exit pupil in the first dimension, the second waveguide different from the first waveguide can enlarge the area of the exit pupil in the second dimension intersecting with the first dimension, the optical waveguide component expands the exit pupil area of an image in a two-dimensional plane, and the imaging effect is better.

In an alternative embodiment, the first dimension is perpendicular to the second dimension, and the directions in which the light rays forming the image exit the optical waveguide assembly are perpendicular to the first dimension and the second dimension, respectively. Therefore, the optical waveguide component realizes the pupil expansion on the plane vertical to the light emergent direction, and the pupil expansion has more direction pertinence.

In an alternative embodiment, the first waveguide is a geometric waveguide and the second waveguide is a diffractive waveguide; alternatively, the first waveguide is a diffractive waveguide and the second waveguide is a geometric waveguide. In this way, using a geometric waveguide as the first waveguide or the second waveguide can avoid a large color deviation in the first dimension or the second dimension; using a diffractive waveguide as the first waveguide or the second waveguide can reduce the difficulty of manufacturing and molding. The geometric wave guide piece and the diffraction wave guide piece are matched with each other and complement each other, so that the image has a better pupil expanding effect on a two-dimensional plane.

In an alternative embodiment, the first waveguide includes a first entrance surface, a first pupil expansion portion, and a first exit surface, and the light rays forming the image enter the first waveguide through the first entrance surface, pass through the first pupil expansion portion, expand the area of an exit pupil in a first dimension, and exit the first waveguide through the first exit surface. Thus, the first entrance surface provides an entrance part of the image light, the first pupil expanding part is used for expanding the area of the exit pupil in the first dimension, the first exit surface provides an exit part of the image light after the pupil expanding, the light can smoothly enter and exit the first waveguide, and the pupil can be expanded stably.

In an optional embodiment, the first waveguide is a geometric waveguide, the first pupil expansion portion is a mirror array portion, the mirror array portion includes a plurality of splitting layers arranged in parallel, and the splitting layers are inclined to the first exit surface, so that the light reflected by the splitting layers is emitted from the first exit surface, the splitting layers are arranged along a first direction, each splitting layer extends along a second direction, and the first direction intersects with the second direction. Therefore, after the light enters the first waveguide from the first incident surface, part of the light is reflected by the previous light splitting layer and exits the first waveguide from the first emergent surface, and then part of the light is transmitted to the next light splitting layer to be reflected and transmitted continuously, and finally the light exiting from the first emergent surface is amplified in the first dimension, namely the exit pupil area of the image in the first dimension is amplified, so that the pupil expansion is simpler and more convenient.

In an alternative embodiment, each of the spectroscopic layers has a spectroscopic surface, the plurality of the spectroscopic layers has m spectroscopic surfaces, and the reflectivity Rn of the nth spectroscopic surface along the first direction satisfies the relation:

0.95/(m-n +1) < Rn <1.05/(m-n +1), and n is more than or equal to 1 and less than or equal to m. Therefore, each light splitting layer has reflectivity increased in a gradient mode in sequence, each amplified exit pupil picture has relatively close luminous flux, and the whole exit pupil picture is more uniform.

In an optional embodiment, the second waveguide includes a second entrance surface, a second pupil expansion portion, and a second exit surface, and the second entrance surface is disposed facing the first exit surface, so that the light emitted from the first exit surface enters the second waveguide through the second entrance surface, expands the area of the exit pupil through the second pupil expansion portion, and then exits through the second exit surface. Thus, the light rays of the first waveguide after expanding the pupil in the first dimension enter the second waveguide from the second entrance surface, the second pupil expanding part is used for expanding the area of the exit pupil in the second dimension intersecting with the first dimension, the second exit surface provides the exit part of the image light rays after expanding the pupil in two dimensions, and the light rays can smoothly enter and exit the second waveguide, so that the pupil can be expanded stably.

In an alternative embodiment, the light emitted from the first exit surface forms an angle α with the second incident surface, and α is in a range of 30 ° ≦ α ≦ 150 °. Therefore, a placing relation which is more favorable for light transmission is formed between the first waveguide and the second waveguide, the first waveguide and the second waveguide are favorable for conducting light in different dimensions respectively, and the optical waveguide component has a two-dimensional pupil expanding effect.

In an optional implementation mode, the second waveguide is a diffraction waveguide, the second pupil expanding portion includes an in-coupling grating portion and an out-coupling grating portion which are arranged at intervals, the in-coupling grating portion is close to the second entrance surface, the out-coupling grating portion is close to the second exit surface, and the light entering the second entrance surface passes through the in-coupling grating portion and the out-coupling grating portion in sequence to expand the area of the exit pupil and then exits from the second exit surface. Therefore, the second waveguide is the diffraction waveguide, light is coupled in through the coupling-in grating of the second pupil expansion part and is coupled out from the coupling-out grating, pupil expansion is achieved in the second dimension, the two different principles of the geometric waveguide and the diffraction waveguide and the waveguide of the structure are used for respectively expanding the area of the exit pupil in the first dimension and the second dimension which are intersected, the process for obtaining the two-dimensional plane pupil expansion is simpler, the structure manufacturing yield is higher, and the image has a better color restoration effect.

In another aspect, the present application also provides a display device comprising an optical waveguide assembly as described above and a light engine for converting an image into light rays entering the optical waveguide assembly such that the optical waveguide assembly expands the area of the exit pupil.

According to the display device, the area of the exit pupil is enlarged on the two-dimensional plane, better imaging quality can be realized while the structure is simple, and the display effect is better.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.

Fig. 1 is a schematic structural diagram of an optical waveguide assembly according to an embodiment of the present application.

Fig. 2 is a schematic diagram of a right-hand configuration of the optical waveguide assembly of fig. 1.

Fig. 3 is a schematic view of a top down configuration of the optical waveguide assembly of fig. 1.

Fig. 4 is a schematic structural diagram of an optical waveguide assembly according to another embodiment of the present application.

Fig. 5 is a schematic structural diagram of a display device according to an embodiment of the present application.

Fig. 6 is a schematic structural diagram of a display device according to another embodiment of the present application.

Description of reference numerals:

100-optical waveguide component, 1-first waveguide, 11-first entrance face, 12-first pupil expansion part, 121-beam splitting layer, 1211-beam splitting face, 13-first exit face, 2-second waveguide, 21-second entrance face, 22-second pupil expansion part, 221-incoupling grating part, 222-outcoupling grating part, 23-second exit face, 200-body part, 210-optical engine, 220-light source, 1000-display device

Detailed Description

In order to make the technical solutions of the present application better understood, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

In this application, the terms "upper", "lower", "left", "right", "front", "rear", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "lateral", "longitudinal", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings. These terms are used primarily to better describe the present application and its embodiments, and are not used to limit the indicated devices, elements or components to a particular orientation or to be constructed and operated in a particular orientation.

Moreover, some of the above terms may be used to indicate other meanings besides the orientation or positional relationship, for example, the term "on" may also be used to indicate some kind of attachment or connection relationship in some cases. The specific meaning of these terms in this application will be understood by those of ordinary skill in the art as the case may be.

Furthermore, the terms "mounted," "disposed," "provided," "connected," and "connected" are to be construed broadly. For example, it may be a fixed connection, a removable connection, or a unitary construction; can be a mechanical connection, or an electrical connection; may be directly connected, or indirectly connected through intervening media, or may be in internal communication between two devices, elements or components. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as appropriate.

Furthermore, the terms "first," "second," and the like, are used primarily to distinguish one device, element, or component from another (the specific nature and configuration may be the same or different), and are not used to indicate or imply the relative importance or number of the indicated devices, elements, or components. "plurality" means two or more unless otherwise specified. It should be noted that, for convenience of description, like reference numerals denote like parts in the embodiments of the present application, and a detailed description of the like parts is omitted in different embodiments for the sake of brevity.

In order to enable the image to have a wider range of exit pupil and better adapt to the range of the movable eye socket, the image can be subjected to two-dimensional pupil expansion, and the two-dimensional pupil expansion can be realized by adopting a single type of optical waveguide structure. For example, only geometric optical waveguide structures; or only a diffractive optical waveguide structure is used for pupil expansion.

If the pupil is expanded for multiple times in a multidimensional way by simply using a geometric optical waveguide structure, the pupil expansion effect in multiple directions needs to be realized on a piece of flat glass, and the pupil expansion effect needs to be realized by a light splitting structure in multiple directions in a specific shape, so that the difficulty of the processing technology is increased, the yield is difficult to control, and the yield is integrally low. The multidimensional pupil expansion can be realized by simply using a geometric optical waveguide structure through the processes of glass gluing, cutting, polishing and the like. The two-dimensional pupil expansion needs to be realized by alternately gluing and arranging at least three glass layers in different directions, so that the two-dimensional pupil expansion is difficult to realize technically.

If the diffraction optical waveguide structure is simply used for multi-dimensional multi-time pupil expansion, light is required to enter different types of diffraction gratings, and the phenomenon of diffraction gradual change dispersion exists along with the increase of the times and types of the light passing through the diffraction gratings. Diffraction gratings diffract light differently for different wavelengths. According to the grating formula sin theta ═ k lambda/d, where theta is the diffraction angle, k is the diffraction order, lambda is the diffraction wavelength, and d is the grating constant, the diffraction angle becomes larger as the diffraction wavelength becomes longer, it can be known that the two pupil expansions are realized by using the pure diffraction grating, which causes the two angular deviations of different color lights at one angle, thus increasing the angular separation of the colors and the color reduction deterioration. And the diffraction optical structures required by a plurality of subareas are different, so that the requirements on micro-nano processing and nano-imprinting processes are higher.

The technical solutions in the embodiments of the present application will be described below with reference to the accompanying drawings. It should be noted that, for convenience of description, like reference numerals denote like parts in the embodiments of the present application, and a detailed description of the like parts is omitted in different embodiments for the sake of brevity.

Referring to fig. 1, 2, 3 and 4, the present application provides an optical waveguide assembly 100 for guiding and projecting an image, the optical waveguide assembly 100 includes a first waveguide 1 and a second waveguide 2, the first waveguide 1 is used for enlarging the area of an exit pupil in a first dimension W1; the image is transmitted through the first waveguide 1 towards the second waveguide 2, the second waveguide 2 being adapted to enlarge the area of the exit pupil in a second dimension W2, the second dimension W2 intersecting the first dimension W1, such that the first waveguide 1 and the second waveguide 2 enlarge the area of the exit pupil in a two-dimensional plane containing the first dimension 1 and the second dimension 2, the first waveguide 1 and the second waveguide 2 being different types of waveguides.

According to the optical waveguide assembly 100 of the present application, the first waveguide 1 can expand the area of the exit pupil in the first dimension W1, and the second waveguide 2 different from the first waveguide 1 can expand the area of the exit pupil in the second dimension W2 intersecting the first dimension W1, so that the optical waveguide assembly 100 expands the pupil in a two-dimensional plane, the exit pupil area of an image is expanded, and the imaging effect is better. The two-dimensional pupil expansion of a single waveguide is restricted by the problems of structural processing and diffraction dispersion, and the first waveguide 1 and the second waveguide 2 are set to be different waveguides, so that the difficulty of structural processing and the degree of diffraction dispersion are balanced, the optical waveguide component 100 can be easily processed on the whole, the generation of diffraction dispersion can be reduced, the production cost is reduced, and the imaging or display effect is improved.

The image of the aperture stop of the optical system in the image space of the optical system is referred to as the "exit pupil" of the system, and the optical system may be the entire optical waveguide assembly 100, the first waveguide 1, or the second waveguide 2. The second waveguide 2 and the first waveguide 1 are arranged at a predetermined angle, which means that the second waveguide 2 and the first waveguide 1 form a certain included angle, and the relative position between the second waveguide 2 and the first waveguide 1 affects the performance of the function thereof. In the figure, the dotted line with arrows is a schematic ray trace.

The dimensions refer to dimensions in a spatial sense, one dimension extending straight in opposite directions. "two-dimensional plane" refers to a plane formed by a first dimension and a second dimension. Optionally, the first dimension W1 is perpendicular to the second dimension W2, and the directions of the light rays forming the image exiting the optical waveguide assembly 100 are perpendicular to the first dimension W1 and the second dimension W2, respectively. In this way, the optical waveguide assembly 100 realizes pupil expansion on a plane perpendicular to the light exit direction, and the pupil expansion is more directional.

Referring to fig. 1 and 2, in some embodiments, the first waveguide 1 is a geometric waveguide and the second waveguide 2 is a diffractive waveguide.

Alternatively, the light rays of the image may enter the diffractive waveguide to expand the pupil in the second dimension W2 after expanding the pupil in the first dimension W1 through the geometric waveguide. Using a geometrical waveguide as the first waveguide 1, large color deviations in the first dimension W1 can be avoided; using a diffractive waveguide as the second waveguide 2 can reduce the difficulty of manufacturing molding in the second dimension W2. The geometric wave guide piece and the diffraction wave guide piece are matched with each other and complement each other, so that the image has a better pupil expanding effect on a two-dimensional plane.

Referring to fig. 4, in other embodiments the first waveguide 1 is a diffractive waveguide and the second waveguide 2 is a geometric waveguide.

Optionally, the light-diffracting waveguides of the image expand the pupil in the second dimension W2, after which the entrance pupil is expanded by the geometric waveguides in the first dimension (the first dimension being in a direction perpendicular to the plane of the paper, not shown in fig. 4). Using a diffractive waveguide as the first waveguide 1 can reduce the difficulty of manufacturing molding in the second dimension W2; using a geometrical waveguide as the second waveguide 2, large color deviations in the first dimension can be avoided. The diffraction waveguide piece and the geometric waveguide piece are matched with each other and complement each other, so that the image has a better pupil expanding effect on a two-dimensional plane.

Referring to fig. 1, 2 and 3, in some embodiments, the first waveguide 1 includes a first entrance surface 11, a first pupil expansion portion 12 and a first exit surface 13, and light forming an image enters the first waveguide 1 from the first entrance surface 11, passes through the first pupil expansion portion 12 to expand the area of the exit pupil in a first dimension W1, and exits the first waveguide 1 from the first exit surface 13. In this way, the first entrance surface 11 provides an entrance portion for the image light, the first pupil expansion portion 12 expands the area of the exit pupil in the first dimension W1, and the first exit surface 13 provides an exit portion for the expanded image light, so that the light can smoothly enter and exit the first waveguide 1, thereby stably expanding the pupil.

Optionally, the first waveguide 1 is a geometric waveguide, the first pupil expansion unit 12 is a mirror array unit, the mirror array unit includes a plurality of light splitting layers 121 arranged in parallel, and the light splitting layers 121 are inclined to the first exit surface 13, so that light reflected by the light splitting layers 121 is emitted from the first exit surface 13, the light splitting layers 121 are arranged along a first direction x, each light splitting layer 121 extends along a second direction y, and the first direction x intersects the second direction y. The plurality of spectroscopic layers 121 may be disposed in close proximity to the contact or may be disposed at intervals. The light splitting layer 121 is a semi-transparent and semi-reflective light splitting sheet or a semi-transparent and semi-reflective light splitting film, in other words, the light splitting layer 121 has a "semi-transparent and semi-reflective" function, that is, the light splitting layer 121 reflects a part of the light beams impinging thereon and transmits a part of the light beams. Thus, after the light enters the first waveguide 1 from the first incident surface 11, a part of the light is reflected by the previous splitting layer 121 and exits the first waveguide 1 from the first exit surface 13, and then a part of the light is transmitted to the next splitting layer 121 to continue to be reflected and transmitted, and finally the light exiting from the first exit surface 13 is expanded on the first dimension W1, that is, the exit pupil area of the image in the first dimension W1 is expanded, so that the pupil expansion is simpler and more convenient.

Optionally, the first direction x is parallel to the first dimension W1, and an included angle β between the second direction y and the first direction x is 135 °, which is more favorable for the light splitting layer 121 to split light.

Optionally, each of the spectroscopic layers 121 has a spectroscopic surface 1211, the spectroscopic layers 121 have m spectroscopic surfaces 1211, the spectroscopic surfaces 1211 are used as surfaces of the spectroscopic layers 121 for realizing a semi-transmission and semi-reflection function, and along the first direction x, the reflectivity Rn of the nth spectroscopic surface 1211 satisfies a relation:

0.95/(m-n +1) < Rn <1.05/(m-n +1), and n is more than or equal to 1 and less than or equal to m. In this way, each of the light splitting layers 121 has a reflectivity that increases in a gradient manner, and each of the expanded exit pupil pictures has a relatively close luminous flux, so that the entire exit pupil picture is more uniform. There are m splitting surfaces 1211, and the reflected energy of each splitting surface 1211 is uniform when the total energy is 1/m. For the nth surface, the n-1 preceding surfaces each have reflected 1/m of the total energy, and thus the energy reaching the nth surface should be 1- (n-1) × 1/m, and if the reflectivity of the nth surface is Rn, (1- (n-1) × 1/m) × Rn ═ 1/m), the energy reflected by the nth surface is also 1/m, and Rn ═ 1/(m-n +1) is obtained, and further considering the allowable tolerance range, 0.95/(m-n +1) < Rn <1.05/(m-n + 1).

Optionally, the second waveguide 2 includes a second entrance surface 21, a second pupil expansion unit 22, and a second exit surface 23, where the second entrance surface 21 is disposed facing the first exit surface 13, so that the light exiting from the first exit surface 13 enters the second waveguide 2 through the second entrance surface 21, expands the area of the exit pupil through the second pupil expansion unit 22, and exits through the second exit surface 23. In this way, the light rays having expanded the pupil of the first waveguide 1 in the first dimension W1 enter the second waveguide 2 from the second entrance surface 21, the second pupil expansion section 22 expands the area of the exit pupil in the second dimension W2 perpendicular to the first dimension W1, and the second exit surface 23 provides an exit section for the image light rays having expanded the pupil in two dimensions, so that the light rays smoothly enter and exit the second waveguide 2, and the pupil can be expanded stably.

Optionally, an included angle between the light emitted from the first exit surface 13 and the second incident surface 21 is α, and α is in a range of 30 ° to 150 °. Therefore, a placing relation which is more favorable for light transmission is formed between the first waveguide 1 and the second waveguide 2, and the first waveguide 1 and the second waveguide 2 are favorable for transmitting light in different dimensions respectively, so that the optical waveguide component has a two-dimensional pupil expanding effect.

Optionally, the included angle α is 90 °. In this way, the light emitted from the first exit surface 13 is perpendicular to the second entrance surface 21, which facilitates the light to enter the second waveguide 2 from the first waveguide 1, thereby facilitating the control of the direction of the expanded pupil of the optical waveguide assembly 100.

Optionally, the first exit surface 13 is disposed opposite to the second exit surface 23. The second incident surface 21 and the second exiting surface 23 may be coplanar and not shared, that is, the second incident surface 21 and the second exiting surface 23 may be distributed in different areas of the same plane.

Referring to fig. 1, 2 and 3, in some embodiments, the second waveguide 2 is a diffractive waveguide, the second pupil expansion portion 22 includes an incoupling grating portion 221 and an outcoupling grating portion 222 that are disposed at intervals, the incoupling grating portion 221 is disposed near the second entrance surface 21, the outcoupling grating portion 222 is disposed near the second exit surface 23, and light entering the second entrance surface 21 sequentially passes through the incoupling grating portion 221 and the outcoupling grating portion 222 to expand the area of the exit pupil and then exits from the second exit surface 23. Thus, the second waveguide 2 is a diffractive waveguide, light is coupled in through the coupling-in grating of the second pupil expansion part 22 and is coupled out from the coupling-out grating, pupil expansion is realized on the second dimension W2 through the light coupling-in and coupling-out effects, and the area of the exit pupil is expanded on the first dimension W1 and the second dimension W2 which are intersected through two different principles and structures of the geometric waveguide and the diffractive waveguide respectively, so that the two-dimensional plane pupil expansion process is simpler, the structure manufacturing yield is higher, and the image has a better color restoration effect. Only the geometric optical waveguide is used as the first dimension pupil expansion, and the structural realization only needs simpler equal interval gluing arrangement, so the complexity is low and the yield is higher. The problem of chromatic dispersion caused by using a geometric waveguide for the first-time pupil expansion is not good, and the chromatic aberration caused by using a diffraction waveguide for two-dimensional pupil expansion is reduced.

Alternatively, the incoupling grating part 221 and the outcoupling grating part 222 are both surface relief gratings, or the incoupling grating part 221 and the outcoupling grating part 222 are both hologram gratings.

Referring to fig. 1, 2 and 3, in an embodiment, the first waveguide 1 is a geometric waveguide, the second waveguide 2 is a diffractive waveguide, and light of an image enters the first waveguide 1 from the first entrance surface 11, is sequentially reflected and transmitted by the plurality of splitting layers 121, and exits from the first exit surface 13, so as to realize a pupil expansion in the first dimension W1; the light emitted from the first exit surface 13 enters the second waveguide 2 from the second entrance surface 21, passes through the incoupling grating part 221 and the outcoupling grating part 222 in this order, and exits from the second exit surface 23, so that pupil expansion in the second dimension W2 is realized. Ultimately appearing as an image passing through the optical waveguide assembly 100 achieves an expanded exit pupil in a two-dimensional plane.

Referring to fig. 5, a display device 1000 is further provided in an embodiment of the present application, which includes the optical waveguide assembly 100 and the light engine 210, wherein the light engine 210 is configured to convert an image into light entering the optical waveguide assembly 100, so that the optical waveguide assembly 100 expands an area of an exit pupil.

Referring to fig. 5 and 6, optionally, the display device 1000 further includes a body portion 200 and a light source 220, and the light waveguide assembly 100, the light source 220 and the light engine 210 are disposed on the body portion 200. The light emitted from the light source 220 is continuously scanned by the light engine 210 to present a projection image, and the light of the image is incident into the optical waveguide assembly 100 to expand the pupil of the image on a two-dimensional plane in the optical waveguide assembly 100.

According to the display device 1000 of the application, the area of the exit pupil is enlarged on the two-dimensional plane, better imaging quality can be realized while the structure is simple, and the display effect is better.

As shown in fig. 6, in some embodiments, the display device 1000 is an Augmented Reality (AR) device, such as AR glasses, a head mounted display, and the like, and the light engine 210 is a Micro-Electro-Mechanical System (MEMS) galvanometer. When the light source 220 emits a light beam onto the MEMS galvanometer, the MEMS galvanometer presents the projected image by continuously scanning, and emits the light of the image into the optical waveguide assembly 100. The display device 1000 in the drawings of the present application is illustrated as AR glasses and should not be construed as limiting the optical waveguide assembly 100 of the embodiments of the present application.

Reference herein to "an embodiment" or "an implementation" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. It is explicitly and implicitly understood by one skilled in the art that the embodiments described herein may be combined with other embodiments.

Finally, it should be noted that the above embodiments are only for illustrating the technical solutions of the present application and not for limiting, and although the present application is described in detail with reference to the above preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions may be made to the technical solutions of the present application without departing from the spirit and scope of the technical solutions of the present application.

Claims

1. An optical waveguide assembly for effecting the conduction of an image, the optical waveguide assembly comprising:

2. The optical waveguide assembly of claim 1, wherein the first dimension is perpendicular to the second dimension, and wherein the light rays forming the image exit the optical waveguide assembly in directions perpendicular to the first dimension and the second dimension, respectively.

3. The optical waveguide assembly of claim 1 wherein the first waveguide is a geometric waveguide and the second waveguide is a diffractive waveguide; alternatively, the first waveguide is a diffractive waveguide and the second waveguide is a geometric waveguide.

4. The optical waveguide assembly of claim 1 wherein the first waveguide comprises a first entrance surface from which light rays forming the image enter the first waveguide, a first pupil expansion portion through which the light rays expand in a first dimension to exit the first waveguide, and a first exit surface from which the light rays exit the first waveguide.

5. The optical waveguide assembly of claim 4, wherein the first waveguide is a geometric waveguide, the first pupil expansion portion is a mirror array portion, the mirror array portion includes a plurality of splitting layers arranged in parallel, and the plurality of splitting layers are inclined to the first exit surface so that light reflected by the plurality of splitting layers exits the first exit surface, the plurality of splitting layers are arranged in a first direction, each of the splitting layers extends in a second direction, and the first direction intersects the second direction.

6. The optical waveguide assembly of claim 5, wherein each of the beam splitting layers has a beam splitting face, the plurality of beam splitting layers has m beam splitting faces, and a reflectivity Rn of an nth beam splitting face along the first direction satisfies a relation:

0.95/(m-n +1) < Rn <1.05/(m-n +1), and n is more than or equal to 1 and less than or equal to m.

7. The optical waveguide assembly of any of claims 4-6, wherein the second waveguide comprises a second entrance surface, a second pupil expansion portion, and a second exit surface, the second entrance surface being disposed facing the first exit surface such that the light exiting the first exit surface enters the second waveguide through the second entrance surface and exits the second exit surface after expanding the area of the exit pupil through the second pupil expansion portion.

8. The optical waveguide assembly of claim 7 wherein the light exiting the first exit surface is at an angle α to the second entrance surface in the range of 30 ° α to 150 °.

9. The optical waveguide assembly of claim 8, wherein the second waveguide is a diffractive waveguide, the second pupil expanding portion includes an in-coupling grating portion and an out-coupling grating portion disposed at an interval, the in-coupling grating portion is disposed near the second entrance surface, the out-coupling grating portion is disposed near the second exit surface, and the light entering the second entrance surface exits from the second exit surface after sequentially passing through the in-coupling grating portion and the out-coupling grating portion to expand the area of the exit pupil.

10. A display device, characterized by: comprising the optical waveguide assembly of any of claims 1-9 and a light engine for converting an image into light rays entering the optical waveguide assembly such that the optical waveguide assembly expands the area of the exit pupil.