Optical waveguide device and display device

Abstract

An optical waveguide device, comprising at least one optical waveguide (100). The optical waveguide (100) comprises a coupling-in area, a coupling-out area, and a propagation area located between the coupling-in area and the coupling-out area; the optical waveguide (100) comprises an optical waveguide body (110); the optical waveguide (100) is used for receiving hybrid light having image information, and coupling target light from the coupling-in area into the optical waveguide body (110), the coupled-in target light is propagated towards the coupling-out area in the propagation area in a total reflection manner, and finally, the target light propagated to the coupling-out area is coupled out of the optical waveguide (100); the optical waveguide body (110) comprises a first surface (110a) and a second surface (110b) arranged opposite to each other; the target light is coupled in from the first surface (110a); the at least one optical waveguide (100) further comprises a light extraction element (120); the light extraction element (120) is arranged on the first surface (110a) and / or the second surface (110b) of the optical waveguide body (110); and at least part of the light extraction element (120) is located in the propagation area, and the light extraction element (120) is used for transmitting non-target light and reflecting the target light.

Description

Optical waveguide device and display device TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of display, and in particular to an optical waveguide device and a display device. BACKGROUND

[0002] With the development of society and the continuous innovation of technology, augmented reality (AR) has gradually entered people's lives. In the aspect of AR augmented reality, optical waveguide technology is an indispensable step. It uses a flat plate optical waveguide sheet with a diffraction grating to transmit and expand the image emitted by the light source assembly to the human eye, so that the user can observe the virtual image superimposed on the world while observing the real world.

[0003] In a multi-piece optical waveguide structure, different optical waveguides are used to transmit light of different wavebands. The design of the device needs to consider the influence of the grating diffraction effect on the photon path. Part of the non-target waveband light will be misdirected into the target optical waveguide structure and fused with the target waveband light. This additional superposition will adversely affect the final display effect.

[0004] The above information disclosed in this section is only for understanding the background of the inventive concept of the present disclosure, and therefore, the above information can contain information that does not constitute the prior art. SUMMARY

[0005] In one aspect, an optical waveguide device is provided, the optical waveguide device comprising at least one optical waveguide, the optical waveguide comprising a coupling-in region, a coupling-out region, and a propagation region between the coupling-in region and the coupling-out region, the optical waveguide comprising an optical waveguide body, the optical waveguide being configured to receive mixed light having image information and to couple target light from the coupling-in region into the optical waveguide body, the coupled-in target light propagating in the propagation region in a total reflection manner towards the coupling-out region, and to couple the target light propagating to the coupling-out region out of the optical waveguide.

[0006] The optical waveguide body comprises a first surface and a second surface arranged oppositely, and the target light is coupled in from the first surface; and

[0007] The at least one optical waveguide further comprises a light extraction element arranged on the first surface and / or the second surface of the optical waveguide body, at least a part of the light extraction element being located in the propagation region, the light extraction element being configured to transmit non-target light and reflect target light.

[0008] According to some example embodiments, the light extraction element comprises a distributed Bragg reflector for transmitting the non-target light and reflecting the target light.

[0009] According to some example embodiments, the at least one light waveguide further comprises a light absorption element disposed on a side of the light extraction element distal to the light waveguide body, the light absorption element for absorbing the non-target light.

[0010] According to some example embodiments, the light absorption element comprises a black matrix material.

[0011] According to some example embodiments, the light waveguide further comprises an in-coupling grating, an out-coupling grating and a turning grating disposed on the first surface of the light waveguide body, the in-coupling grating being located at the in-coupling region, the out-coupling grating being located at the out-coupling region, and the turning grating being located at the propagation region.

[0012] wherein a footprint of the turning grating on the light waveguide body is located on a side of a footprint of the in-coupling grating on the light waveguide body along a second direction, and a footprint of the turning grating on the light waveguide body is located on a side of a footprint of the out-coupling grating on the light waveguide body along a first direction, the first direction intersecting the second direction.

[0013] According to some example embodiments, the light extraction element comprises a first light extraction element and / or a second light extraction element.

[0014] wherein along a propagation direction of the target light, a footprint of the first light extraction element on the light waveguide body is located between a footprint of the in-coupling grating on the light waveguide body and a footprint of the turning grating on the light waveguide body; and

[0015] along a propagation direction of the target light, a footprint of the second light extraction element on the light waveguide body is located between a footprint of the out-coupling grating on the light waveguide body and a footprint of the turning grating on the light waveguide body.

[0016] According to some example embodiments, the footprint of the first light extraction element on the light waveguide body is tangential to the footprint of the in-coupling grating on the light waveguide body, and / or the footprint of the first light extraction element on the light waveguide body is tangential to the footprint of the turning grating on the light waveguide body; and

[0017] A projection of the second light extraction element on the optical waveguide body is tangential to a projection of the out-coupling grating on the optical waveguide body, and / or a projection of the second light extraction element on the optical waveguide body is tangential to a projection of the turning grating on the optical waveguide body.

[0018] According to some example embodiments, a projection of the first light extraction element on the optical waveguide body is spaced apart from a projection of the in-coupling grating on the optical waveguide body, and / or a projection of the first light extraction element on the optical waveguide body is spaced apart from a projection of the turning grating on the optical waveguide body; and

[0019] A projection of the second light extraction element on the optical waveguide body is spaced apart from a projection of the out-coupling grating on the optical waveguide body, and / or a projection of the second light extraction element on the optical waveguide body is spaced apart from a projection of the turning grating on the optical waveguide body.

[0020] According to some example embodiments, a dimension of a projection of the first light extraction element on the optical waveguide body along the first direction is greater than or equal to a dimension of a projection of the in-coupling grating on the optical waveguide body along the first direction, and / or a dimension of a projection of the first light extraction element on the optical waveguide body along the first direction is greater than or equal to a dimension of a projection of the turning grating on the optical waveguide body along the first direction; and

[0021] A dimension of a projection of the second light extraction element on the optical waveguide body along the second direction is greater than a dimension of a projection of the out-coupling grating on the optical waveguide body along the second direction, and / or a dimension of a projection of the second light extraction element on the optical waveguide body along the second direction is greater than a dimension of a projection of the turning grating on the optical waveguide body along the second direction.

[0022] According to some example embodiments, in at least one optical waveguide, the in-coupling grating is configured to in-couple target light rays and reflect non-target light rays.

[0023] According to some example embodiments, the in-coupling grating comprises a plurality of in-coupling grating bars arranged at intervals, the in-coupling grating bars having a structure of a distributed Bragg reflector, the in-coupling grating bars being configured to reflect non-target light rays and transmit target light rays.

[0024] In another aspect, there is provided a display device comprising an image source and the optical waveguide device as described above;

[0025] wherein the image source is configured to emit mixed light rays having image information; and

[0026] The light waveguide device comprises at least two light waveguides, which are arranged on one side of the light exit surface of the image source and along the light exit direction of the image source.

[0027] According to some exemplary embodiments, the target light rays coupled into different light waveguides have different wavelengths, and the closer to the image source, the shorter the wavelength of the target light rays coupled into the light waveguide.

[0028] At least in the light waveguide closest to the image source, the light extraction element is arranged on the light waveguide body.

[0029] According to some exemplary embodiments, in the light waveguide closest to the image source, the light extraction element is arranged on the first surface of the light waveguide body; and / or

[0030] In the light waveguide farthest from the image source, the light extraction element is arranged on the second surface of the light waveguide body.

[0031] According to some exemplary embodiments, the light waveguide comprises a coupling grating arranged on the first surface of the light waveguide body and located in the coupling region.

[0032] In the light waveguide farthest from the image source, the coupling grating is used to couple in target light rays and reflect non-target light rays. BRIEF DESCRIPTION OF DRAWINGS

[0033] Other objects and advantages of the present disclosure will be apparent and help to understand the present disclosure by the following description of the present disclosure with reference to the accompanying drawings.

[0034] FIG. 1 schematically shows a side view of a light waveguide device according to some embodiments of the present disclosure.

[0035] FIG. 2 schematically shows a top view of a light waveguide device according to some embodiments of the present disclosure.

[0036] FIG. 3 schematically shows a side view of a light extraction element in a light waveguide device according to some embodiments of the present disclosure.

[0037] FIG. 4 schematically shows a transmittance spectrum of a distributed Bragg reflector in a light waveguide device according to some embodiments of the present disclosure.

[0038] FIG. 5 schematically shows a side view of a light waveguide device according to some other embodiments of the present disclosure.

[0039] FIG. 6 schematically shows a top view of a light waveguide device according to some embodiments of the present disclosure.

[0040] FIG. 7 schematically illustrates a top view of an optical waveguide device, according to some embodiments of the present disclosure.

[0041] FIG. 8 schematically illustrates a top view of an optical waveguide device, according to some embodiments of the present disclosure.

[0042] FIG. 9 schematically illustrates a top view of an optical waveguide device, according to some embodiments of the present disclosure.

[0043] FIG. 10 schematically illustrates a side view of an optical waveguide device, according to some embodiments of the present disclosure.

[0044] FIG. 11 schematically illustrates a zoomed-in view of region SI in FIG. 10.

[0045] FIG. 12 schematically illustrates a side view of a display device, according to some embodiments of the present disclosure.

[0046] FIG. 13 schematically illustrates a side view of a display device, according to some embodiments of the present disclosure.

[0047] FIG. 14 schematically illustrates a side view of a display device, according to some embodiments of the present disclosure.

[0048] It is noted that, for the sake of clarity and further exemplification, the dimensions of the layers, structures or regions can be exaggerated or minimized in the drawings used herewith in describing the embodiments of the present disclosure. Thus, the dimensions of the various features of the drawings are not necessarily to scale with one another. DETAILED DESCRIPTION

[0049] In the following description, for the purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the various exemplary embodiments. It is apparent, however, that various exemplary embodiments can be practiced without using these specific details or with one or more equivalent arrangements. In other instances, well-known structures and devices are shown in block diagram form in order to avoid unnecessarily obscuring the various exemplary embodiments. Further, various exemplary embodiments can be different from one another and still come within the scope of the inventive concepts. For example, specific shapes, configurations, and features of the exemplary embodiments can be used or implemented in other exemplary embodiments without departing from the inventive concepts.

[0050] In the drawings, the size and relative sizes of elements and regions can be exaggerated for clarity and / or descriptive purposes. As such, the dimensions and relative sizes of various elements and regions shown in the figures can not be to scale with one another. When the same element is referred to in various places in the description, the same reference numeral is used throughout. Wherever possible, the same reference numbers are used in the drawings and the following description. When the terms "first", "second", "third", etc. are used in the description, they are used to indicate different aspects of the application, and are not necessarily used to indicate a particular order or sequence. The terms "first", "second", "third", etc. are also used to indicate different aspects of the application, and are not necessarily used to indicate a particular order or sequence.

[0051] When an element is referred to as being "on" another element, "connected to" another element, or "coupled to" another element, it can be directly on, directly connected to, or directly coupled to the other element or intervening elements can be present. In contrast, when an element is referred to as being "directly on," "directly connected to," or "directly coupled to" another element, there are no intervening elements present. Other terms of relationship between elements are to be interpreted in a like fashion, such as "between" versus "directly between," "adjacent" versus "directly adjacent," or "on" versus "directly on," etc. In addition, the term "connected" can refer to physical or electrical connection, communication connection, and / or fluid connection. Furthermore, the X-axis, Y-axis, and Z-axis are not limited to three axes of a rectangular coordinate system, and can be interpreted in a broader sense. For example, the X-axis, Y-axis, and Z-axis can be perpendicular to each other, or can represent different directions that are not perpendicular to each other. For the purposes of the present disclosure, "at least one of X, Y, and Z" and "at least one selected from the group consisting of X, Y, and Z" can be interpreted to be any one of X, Y, Z, or any combination of two or more of X, Y, and Z, such as XYZ, XY, YZ, and XZ. As used herein, the term "and / or" includes any and all combinations of one or more of the associated items.

[0052] It will be understood that, although the terms first, second, etc. can be used herein to describe different elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of example embodiments.

[0053] FIG. 1 schematically illustrates a side view of an optical waveguide device according to some embodiments of the present disclosure. FIG. 2 schematically illustrates a top view of an optical waveguide device according to some embodiments of the present disclosure.

[0054] Referring to FIGS. 1 and 2, the optical waveguide device includes at least one optical waveguide including an in-coupling region A1, an out-coupling region A3, and a propagation region A2 between the in-coupling region A1 and the out-coupling region A3. The optical waveguide 100 includes an optical waveguide body 110, and is configured to receive mixed light rays having image information and to filter the mixed light rays to in-couple target light rays from the in-coupling region A1 into the optical waveguide body 110, propagate the in-coupled target light rays in the propagation region A2 toward the out-coupling region A3 in a total reflection manner, and out-couple the target light rays that propagate to the out-coupling region A3 out of the optical waveguide 100.

[0055] Referring to FIG. 1, the light waveguide body 110 is a light guide plate for conducting target light in a total reflection manner. The light waveguide body 110 can be made of a polymer material or an inorganic material with a relatively high refractive index, for example, the material of the light waveguide body 110 is selected from glass with a refractive index greater than or equal to 1.5, but is not limited thereto. The light waveguide body 110 includes a first surface 110a and a second surface 110b arranged oppositely, and the target light is coupled into the light waveguide body 110 from the first surface 110a.

[0056] Referring to FIG. 2, the first surface 110a of the light waveguide body 110 is provided with a coupling-in grating 140, a turning grating 150, and a coupling-out grating 160. The coupling-in grating 140 is arranged in a coupling-in region A1, the turning grating 150 is arranged in a propagation region A2, and the coupling-out grating 160 is arranged in a coupling-out region A3. The orthogonal projection of the turning grating 150 on the light waveguide body 110 is located on one side of the orthogonal projection of the coupling-in grating 140 on the light waveguide body 110 along a second direction Y, and the orthogonal projection of the turning grating 150 on the light waveguide body 110 is located on one side of the orthogonal projection of the coupling-out grating 160 on the light waveguide body 110 along a first direction X, and the first direction X intersects the second direction Y. For example, the first direction X is perpendicular to the second direction Y.

[0057] It is further explained that the coupling-in region A1 should be understood as a region where the target light is coupled into the light waveguide body 110, and the region provided with the coupling-in grating 140 is the coupling-in region A1. The coupling-out region A3 should be understood as a region where the target light is coupled out of the light waveguide body 110, and the region provided with the coupling-out grating 160 is the coupling-out region A3. The propagation region A2 has no specific division limit, and the region through which the target light propagates from the coupling-in region A1 to the coupling-out region A3 is the propagation region A2. In theory, the region of the light waveguide body 110 except the coupling-in region A1 and the coupling-out region A3 can be used as the propagation region A2, but in actual application, in order to ensure that the target light can effectively propagate in the light waveguide body 110, the setting range of the light waveguide body 110 is slightly larger than the propagation region A2.

[0058] For example, the structure of the in-coupling grating 140 is set according to the target wavelength band to be in-coupled. When the target light with the wavelength in the target wavelength band is incident on the in-coupling grating 140, diffraction occurs, the propagation direction of the target light is changed, and the target light is in-coupled into the optical waveguide body 110 at a specific incident angle. The specific incident angle is set to be greater than the critical angle at which total reflection of the target light occurs in the optical waveguide body 110. Therefore, after the target light is in-coupled into the optical waveguide body 110 by the in-coupling grating 140, the target light propagates in the optical waveguide body 110 in the form of total reflection. The non-target light with the wavelength outside the target wavelength band is not in-coupled into the optical waveguide body 110 by the in-coupling grating 140, but continues to propagate through the in-coupling grating 140 and the optical waveguide body 110.

[0059] For example, the turning grating 150 is configured to one-dimensionally expand the total reflection target light in the optical waveguide body 110, divide the field of view, and generally propagate the left field of view and the right field of view in two directions, thereby increasing the field of view.

[0060] For example, the out-coupling grating 160 is used to change the propagation direction of the target light propagating into the out-coupling area A3, so that the target light is not totally reflected in the optical waveguide body 110, but is emitted from the optical waveguide body 110 at a predetermined emission angle. The target light is expanded in the propagation direction, and after being out-coupled from the optical waveguide body 110, enters the human eye, thereby achieving the purpose of pupil expansion.

[0061] It is additionally explained that the target light should be understood as a collection of all light with the wavelength in the target wavelength band, and the non-target light should be understood as a collection of all light with the wavelength outside the target wavelength band. The target wavelength band of the target light is set according to the actual display requirement. For example, when the optical waveguide is used to conduct blue light, the target wavelength band of the optical waveguide can be set to 440-480 nm. Therefore, the non-target light is light with the wavelength greater than 480 nm or the wavelength less than 440 nm. When the optical waveguide device has multiple optical waveguides, the wavelength bands of the target light of different optical waveguides can not coincide, that is, different optical waveguides are used to conduct light with different wavelengths.

[0062] With reference to FIGS. 1 and 2, the at least one optical waveguide 100 further comprises a light extraction element 120, which can be disposed on the first surface 110a of the optical waveguide body 110, or the second surface 110b of the optical waveguide body 110, or the first surface 110a and the second surface 110b of the optical waveguide body 110 are respectively provided with light extraction elements. FIG. 1 schematically shows a case where the light extraction element 120 is disposed on the second surface 110b of the optical waveguide body 110. The light extraction element 120 is configured to transmit the non-target light and reflect the target light, and at least a part of the light extraction element 120 is located in the propagation region A2. In this way, the target light coupled into the optical waveguide body 110 is reflected by the light extraction element 120 and continues to propagate in the optical waveguide body 110, while the non-target light coupled into the optical waveguide body 110 by the coupling-in grating 140 is transmitted by the light extraction element 120 and exits the optical waveguide body 110, i.e., the non-target light is extracted by the light extraction element 120 and does not continue to propagate, thereby improving the color purity of the light propagating in the optical waveguide.

[0063] It should be understood that, in theory, only the target light with a wavelength within the target wavelength range can be coupled into the optical waveguide body by the coupling-in grating, but due to the manufacturing precision of the coupling-in grating and other factors, a small amount of non-target light can also be coupled into the optical waveguide body by the coupling-in grating. By disposing the light extraction element, the non-target light can be effectively extracted from the optical waveguide body, thereby improving the color purity of the light propagating in the optical waveguide, and further improving the display effect of the display device manufactured by the optical waveguide device.

[0064] According to some exemplary embodiments, the light extraction element 120 comprises a distributed Bragg reflector configured to transmit the non-target light and reflect the target light. Of course, the light extraction element 120 can also be other optical devices with selective reflection of light with a specific wavelength range, which is not limited in the embodiments of the present disclosure.

[0065] FIG. 3 schematically shows a side view of a light extraction element in an optical waveguide device according to some embodiments of the present disclosure.

[0066] For example, with reference to FIG. 3, a distributed Bragg reflector is used as the light extraction element, which comprises high refractive index film layers 121 and low refractive index film layers 122 alternately disposed perpendicular to the surface of the optical waveguide body. By comprehensively setting the refractive index, thickness, and number of layers of the high refractive index film layers 121 and the low refractive index film layers 122, the light extraction element can transmit the non-target light and reflect the target light.

[0067] It is to be further understood that the distributed Bragg reflector described in the embodiments of the present disclosure is a man-made microstructure material stacked by at least two media with different refractive indexes in a certain period, and the media are arranged in a periodic order, so that the moving photons are modulated to form a band structure, and when the structure parameters are appropriate, there may be a photonic bandgap structure similar to the electronic bandgap between the photon bands. Therefore, the distributed Bragg reflector can be used to regulate the transmission of light, and by adjusting the structure, part of the light in a certain wave band cannot propagate in the distributed Bragg reflector, thereby realizing the regulation and control of the propagation of light.

[0068] The width and position of the photonic bandgap of the distributed Bragg reflector are affected by the stacking period and the stacking thickness. When the optical thickness of the single-layer medium is λ0 / 4, the photonic bandgap will appear at the minimum value of the transmittance at λ0, and λ0 is defined as the center wavelength of the photonic bandgap. According to formula (1-1), the width of the photonic bandgap can be calculated, where n H is the refractive index of the high-refractive film layer, and n L is the refractive index of the low-refractive film layer.

[0069] As can be seen from formula (1-1), the greater the refractive index difference of the material, the greater the width of the photonic bandgap Δλ. For example, the material of the high-refractive film layer 121 includes Nb2O5, and the material of the low-refractive film layer 122 includes SiO2.

[0070] Exemplarily, the optical waveguide is used to conduct blue light, that is, the target light of the optical waveguide has a wavelength of 440nm-480nm. However, in actual use, the optical waveguide can couple in green light and red light with a wavelength of 510nm or more. According to the calculation of formula (1-2) below, the light with a wavelength of 480nm will propagate in the optical waveguide body at an angle of 59° through the diffraction of the coupling grating of the optical waveguide, and the light with a wavelength of 510nm will propagate in the optical waveguide body at an angle of 65° through the diffraction of the coupling grating of the optical waveguide.

[0071] Formula (1-2) below is the grating equation, where n0 is the refractive index of the grating medium, n1 is the refractive index of the grating, θ0 is the incident angle, θ1 is the diffraction angle, λ is the wavelength, d is the grating constant, and m is the diffraction order.

[0072] According to formula (1-2), for the same coupling grating, when the incident angle is constant, the longer the wavelength, the larger the diffraction angle. Therefore, the diffraction angle of the target light coupled into the optical waveguide body through the coupling grating is less than or equal to 59°, and the diffraction angle of the non-target light coupled into the optical waveguide body through the coupling grating is greater than 65°. According to the maximum diffraction angle 59° of the target light, the minimum diffraction angle 65° of the non-target light, and the wavelength range 440nm-480nm of the target light, a specific distributed Bragg reflector is designed as the light extraction element of the optical waveguide, and the transmittance of the distributed Bragg reflector for the full visible light band with an incident angle of 59° and the full visible light band with an incident angle of 65° is simulated and analyzed, and the transmittance spectrum diagram obtained is shown in FIG. 4. As shown in FIG. 4, the transmittance of the light with an incident angle of 59° at a wavelength of 480nm is almost 0%, that is, the blue light with a wavelength of 480nm and a diffraction angle of 59° is reflected when it hits the distributed Bragg reflector. The diffraction angle of the target light with a wavelength less than 480nm is less than 59°, and the transmittance spectrum of the light with a diffraction angle less than 59° is shifted to a longer wavelength compared with the transmittance spectrum of the light with a diffraction angle of 59°. Obviously, the transmittance of the shifted spectrum diagram in the blue light band is almost 0, therefore, almost all target light in the target wavelength band is reflected by the distributed Bragg reflector. The transmittance of the light with an incident angle of 65° at a wavelength of 510nm is almost 100%, that is, the green light with a wavelength of 510nm and a diffraction angle of 65° is transmitted when it hits the distributed Bragg reflector. The diffraction angle of the target light with a wavelength greater than 510nm is greater than 65°, and the transmittance spectrum of the light with a diffraction angle greater than 65° is shifted to a shorter wavelength compared with the transmittance spectrum of the light with a diffraction angle of 65°. Obviously, the transmittance of the shifted spectrum diagram in the green light band and the red light band is high, therefore, almost all target light in the non-target wavelength band is transmitted by the distributed Bragg reflector.

[0073] It should be understood that the above is only an example of designing a specific distributed Bragg reflector in combination with a specific optical waveguide to illustrate the design principle of the distributed Bragg reflector, and does not mean that the transmittance spectrum of the distributed Bragg reflector in actual application must be as shown in FIG. 4.

[0074] FIG. 5 schematically shows a side view of an optical waveguide device according to further embodiments of the present disclosure.

[0075] According to some exemplary embodiments, referring to FIG. 5, the at least one optical waveguide further comprises a light absorption element 130 disposed on the side of the light extraction element 120 away from the optical waveguide body 110, and the light absorption element 130 is configured to absorb the non-target light. That is, the non-target light extracted by the light extraction element 120 is incident on the light absorption element 130 and is absorbed by the light absorption element 130. With this arrangement, when there are multiple optical waveguides in the optical waveguide device, the problem of light crosstalk caused by the extracted non-target light being incident on the adjacent optical waveguide again can be effectively avoided.

[0076] According to some exemplary embodiments, referring to FIG. 5, in order to ensure that the non-target light extracted by the light extraction element 120 is sufficiently absorbed by the light absorption element 130, the light absorption element 130 is arranged to cover the surface of the light extraction element 120 away from the optical waveguide body 110, i.e., the orthographic projection of the light absorption element 130 on the optical waveguide body 110 covers the orthographic projection of the light extraction element 120 on the optical waveguide body 110.

[0077] According to some exemplary embodiments, the material of the light absorption element 130 can include a light-absorbing material that has a specific absorption effect on the non-target light, or the material of the light absorption element 130 can include a light-absorbing material that has an absorption effect on all wavelengths of visible light. For example, the material of the light absorption element 130 can include a black matrix material, which is a material commonly used in the display field, has a low price, and has a mature preparation process.

[0078] FIG. 6 schematically shows a top view of an optical waveguide device according to some embodiments of the present disclosure.

[0079] According to some exemplary embodiments, referring to FIG. 6, the light extraction element 120 includes a first light extraction element 121, and along the propagation direction of the target light, the orthographic projection of the first light extraction element 121 on the optical waveguide body 110 is located between the orthographic projection of the in-coupling grating 140 on the optical waveguide body 110 and the orthographic projection of the turning grating 150 on the optical waveguide body 110. With this arrangement, the target light doped with non-target light will be incident on the interface between the optical waveguide body 110 and the first light extraction element 121 during the propagation of the target light from the in-coupling grating 140 to the turning grating 150, the target light incident on the interface is reflected and continues to propagate in the optical waveguide body 110, and the non-target light incident on the interface is transmitted out of the optical waveguide body 110 by the first light extraction element 121, i.e., the first light extraction element 121 can effectively extract the non-target light from the optical waveguide body 110.

[0080] According to some exemplary embodiments, referring to FIG. 2, the light extraction element 120 comprises a second light extraction element 122, a projection of the second light extraction element 122 on the light waveguide body 110 along a propagation direction of the target light rays is located between a projection of the out-coupling grating 160 on the light waveguide body 110 and a projection of the turning grating 150 on the light waveguide body 110. With this arrangement, the target light rays doped with the non-target light rays, in the process of propagating from the turning grating 150 to the in-coupling grating 140, will be incident to an interface between the light waveguide body 110 and the second light extraction element 122, the target light rays incident to the interface will be reflected and continue to propagate in the light waveguide body 110, and the non-target light rays incident to the interface will be transmitted out of the light waveguide body 110 from the second light extraction element 122, i.e., the second light extraction element 122 can effectively extract the non-target light rays from the light waveguide body 110.

[0081] FIG. 7 schematically shows a top view of a light waveguide device according to some other embodiments of the present disclosure.

[0082] According to some exemplary embodiments, referring to FIG. 7, the light extraction element 120 comprises a first light extraction element 121 and a second light extraction element 122. That is, the light extraction element 120 is arranged between the in-coupling grating 140 and the turning grating 150, and between the turning grating 150 and the out-coupling grating 160. With this arrangement, the non-target light rays doped in the target light rays can be extracted in the process of propagating from the in-coupling grating 140 to the turning grating 150 and in the process of propagating from the turning grating 150 to the out-coupling grating 160, thereby increasing the extraction rate of the non-target light rays from the light waveguide body 110.

[0083] According to some exemplary embodiments, referring to FIG. 6 and FIG. 7, a projection of the first light extraction element 121 on the light waveguide body 110 is spaced apart from a projection of the in-coupling grating 140 on the light waveguide body 110, and the projection of the first light extraction element 121 on the light waveguide body 110 is spaced apart from a projection of the turning grating 150 on the light waveguide body 110.

[0084] According to some exemplary embodiments, referring to FIG. 2 and FIG. 7, a projection of the second light extraction element 122 on the light waveguide body 110 is spaced apart from a projection of the out-coupling grating 160 on the light waveguide body 110, and the projection of the second light extraction element 122 on the light waveguide body 110 is spaced apart from a projection of the turning grating 150 on the light waveguide body 110.

[0085] FIG. 8 schematically shows a top view of a light waveguide device according to some other embodiments of the present disclosure.

[0086] According to some example embodiments, referring to FIG. 8, the orthogonal projection of the first light extraction element 121 on the optical waveguide body 110 is tangential to the orthogonal projection of the in-coupling grating 140 on the optical waveguide body 110, and the orthogonal projection of the first light extraction element 121 on the optical waveguide body 110 is spaced apart from the orthogonal projection of the out-coupling grating 150 on the optical waveguide body 110.

[0087] Of course, according to actual needs, the orthogonal projection of the first light extraction element on the optical waveguide body can also be tangential to the orthogonal projection of the out-coupling grating on the optical waveguide body, or the orthogonal projection of the first light extraction element on the optical waveguide body is tangential to the orthogonal projection of the out-coupling grating on the optical waveguide body and the orthogonal projection of the in-coupling grating on the optical waveguide body, respectively. The size of the first light extraction element in the propagation direction of the target light ray between the in-coupling grating and the out-coupling grating can be set according to actual process needs. In theory, the larger the size, the higher the extraction rate of non-target light rays, i.e., when the orthogonal projection of the first light extraction element on the optical waveguide body is tangential to the orthogonal projection of the out-coupling grating on the optical waveguide body and the orthogonal projection of the in-coupling grating on the optical waveguide body, respectively, it is more beneficial to extract non-target light rays from the optical waveguide body.

[0088] It is additionally explained that the orthogonal projection of the two structures mentioned in the embodiments of the present disclosure should be understood as that a part of the edge of the orthogonal projection of one structure substantially coincides with a part of the edge of the orthogonal projection of the other structure, and the orthogonal projection of the other part of one structure does not overlap with the orthogonal projection of the other part of the other structure.

[0089] FIG. 9 schematically shows a top view of an optical waveguide device according to still other embodiments of the present disclosure.

[0090] According to some example embodiments, referring to FIG. 9, the orthogonal projection of the second light extraction element 122 on the optical waveguide body 110 is tangential to the orthogonal projection of the out-coupling grating 150 on the optical waveguide body 110, and the orthogonal projection of the second light extraction element 122 on the optical waveguide body 110 is spaced apart from the orthogonal projection of the in-coupling grating 140 on the optical waveguide body 110.

[0091] Of course, according to actual requirements, the second light extraction element can also be set to be tangent to the orthographic projection of the coupling-out grating on the optical waveguide body, or the orthographic projection of the first light extraction element on the optical waveguide body is tangent to the orthographic projection of the turning grating on the optical waveguide body and the orthographic projection of the coupling-out grating on the optical waveguide body, respectively. The size of the second light extraction element along the propagation direction of the target light between the coupling-out grating and the turning grating can be set according to actual process requirements. In theory, the larger the size, the higher the extraction rate of non-target light, that is, when the orthographic projection of the second light extraction element on the optical waveguide body is tangent to the orthographic projection of the turning grating on the optical waveguide body and the orthographic projection of the coupling-out grating on the optical waveguide body, respectively, it is more beneficial to extract non-target light from the optical waveguide body.

[0092] According to some exemplary embodiments, the larger the size of the orthographic projection of the first light extraction element on the optical waveguide body along the first direction, the higher the extraction rate of non-target light. In order to make the extraction rate of non-target light meet the process requirements, the size of the orthographic projection of the first light extraction element on the optical waveguide body along the first direction can be set according to the size of the orthographic projection of the coupling-in grating and the turning grating on the optical waveguide body along the first direction. For example, the size of the orthographic projection of the first light extraction element on the optical waveguide body along the first direction is greater than or equal to the size of the orthographic projection of the coupling-in grating on the optical waveguide body along the first direction, or the size of the orthographic projection of the first light extraction element on the optical waveguide body along the first direction is greater than or equal to the size of the orthographic projection of the turning grating on the optical waveguide body along the first direction, or the size of the orthographic projection of the first light extraction element on the optical waveguide body along the first direction is greater than or equal to the size of the orthographic projection of the coupling-in grating on the optical waveguide body along the first direction and the size of the orthographic projection of the first light extraction element on the optical waveguide body along the first direction is greater than or equal to the size of the orthographic projection of the turning grating on the optical waveguide body along the first direction.

[0093] Illustratively, referring to FIG. 6, the size of the orthographic projection of the first light extraction element 121 on the optical waveguide body 110 along the first direction X is equal to the size of the orthographic projection of the coupling-in grating 140 on the optical waveguide body 110 along the first direction X, and the size of the orthographic projection of the first light extraction element 121 on the optical waveguide body 110 along the first direction X is greater than the size of the orthographic projection of the turning grating 150 on the optical waveguide body 110 along the first direction X.

[0094] It is to be understood that the size of the orthogonal projection of the second light extraction element along the second direction on the light waveguide body is the maximum size of the orthogonal projection of the second light extraction element along the second direction. For example, when the orthogonal projection of the second light extraction element along the second direction is distributed with equal width in the vertical direction of the second direction, the size of the orthogonal projection of the second light extraction element along the second direction is the same at any position of the orthogonal projection of the second light extraction element along the second direction. When the orthogonal projection of the second light extraction element along the second direction is distributed with unequal width in the vertical direction of the second direction, the width of the orthogonal projection of the second light extraction element at the widest position in the vertical direction of the second direction is the size of the orthogonal projection of the second light extraction element along the second direction.

[0095] According to some exemplary embodiments, the larger the size of the orthogonal projection of the second light extraction element along the second direction on the light waveguide body, the higher the extraction rate of the non-target light. In order to make the extraction rate of the non-target light meet the process requirements, the size of the orthogonal projection of the second light extraction element along the second direction on the light waveguide body can be set according to the size of the orthogonal projection of the out-coupling grating and the turning grating along the second direction on the light waveguide body. For example, the size of the orthogonal projection of the second light extraction element along the second direction on the light waveguide body is greater than or equal to the size of the orthogonal projection of the out-coupling grating along the second direction on the light waveguide body, or the size of the orthogonal projection of the second light extraction element along the second direction on the light waveguide body is greater than or equal to the size of the orthogonal projection of the turning grating along the second direction on the light waveguide body, or the size of the orthogonal projection of the second light extraction element along the second direction on the light waveguide body is greater than or equal to the size of the orthogonal projection of the out-coupling grating along the second direction on the light waveguide body and the size of the orthogonal projection of the second light extraction element along the second direction on the light waveguide body is greater than or equal to the size of the orthogonal projection of the turning grating along the second direction on the light waveguide body.

[0096] For example, referring to FIG. 9, the size of the orthogonal projection of the second light extraction element 120 along the second direction Y on the light waveguide body 110 is greater than the size of the orthogonal projection of the out-coupling grating 160 along the second direction Y on the light waveguide body 110, and the size of the orthogonal projection of the second light extraction element 120 along the second direction Y on the light waveguide body 110 is equal to the size of the orthogonal projection of the turning grating 150 along the second direction Y on the light waveguide body 110.

[0097] It is to be understood that the size of the orthogonal projection of the second light extraction element along the second direction on the light waveguide body is the maximum size of the orthogonal projection of the second light extraction element along the second direction. For example, when the orthogonal projection of the second light extraction element along the second direction is distributed with equal width in the vertical direction of the second direction, the size of the orthogonal projection of the second light extraction element along the second direction is the same at any position of the orthogonal projection of the second light extraction element along the second direction. When the orthogonal projection of the second light extraction element along the second direction is distributed with unequal width in the vertical direction of the second direction, the width of the orthogonal projection of the second light extraction element at the widest position in the vertical direction of the second direction is the size of the orthogonal projection of the second light extraction element along the second direction.

[0098] According to some exemplary embodiments, a plurality of first light extraction elements can be arranged at intervals between the in-coupling grating and the turning grating. The plurality of first light extraction elements can be arranged along a first direction, and the plurality of first light extraction elements can also be arranged along a second direction.

[0099] According to some exemplary embodiments, a plurality of second light extraction elements can be arranged at intervals between the out-coupling grating and the turning grating. The plurality of second light extraction elements can be arranged along a first direction, and the plurality of second light extraction elements can also be arranged along a second direction.

[0100] According to some exemplary embodiments, the shape of the orthographic projection of the light extraction element on the light waveguide body can be rectangular, parallelogram, trapezoidal, or elliptical, etc.

[0101] FIG. 10 schematically shows a side view of a light waveguide device according to yet some embodiments of the present disclosure.

[0102] According to some exemplary embodiments, referring to FIG. 10, in at least one light waveguide, the in-coupling grating 140 is used to in-couple the target light and reflect the non-target light, and by designing the in-coupling grating 140, the in-coupling grating 140 has a specific reflection effect on the non-target light, i.e., the non-target light incident on the in-coupling grating 140 is reflected and cannot be in-coupled into the light waveguide body 110, thereby improving the color purity of the light in-coupled into the light waveguide body 110.

[0103] FIG. 11 schematically shows an enlarged view of the region S1 in FIG. 10.

[0104] According to some exemplary embodiments, referring to FIGS. 10 and 11, the in-coupling grating 140 includes a plurality of in-coupling grating bars 141 arranged at intervals, and the in-coupling grating bar 141 has a structure of a distributed Bragg reflector, i.e., the in-coupling grating bar 141 includes high-refractive-index grating sub-bars 141a and low-refractive-index grating sub-bars 141b alternately and stacked in a direction perpendicular to the first surface 110a, and the refractive index of the high-refractive-index grating sub-bar 141a is greater than the refractive index of the low-refractive-index grating sub-bar 141b. According to the wavelength band of the non-target light to be reflected, the refractive index, thickness, and number of layers of the high-refractive-index grating sub-bar 141a and the low-refractive-index grating sub-bar 141b are designed, so that the in-coupling grating bar 141 can transmit the target light and reflect the non-target light.

[0105] In the actual manufacturing process, a complete distributed Bragg reflector can be prepared first in the in-coupling region of the first surface of the light waveguide body, and then the distributed Bragg reflector is etched to form a plurality of parallel etched grooves, i.e., an in-coupling grating with a distributed Bragg reflector structure.

[0106] According to some exemplary embodiments, a display device is provided, the display device comprising an image source configured to emit mixed light rays having image information and a light waveguide device as described above, the light waveguide device comprising at least two light waveguides arranged along an emission direction of the image source and located on a side of an emission surface of the image source, different light waveguides being configured to couple-in target light rays having different wavelengths, and the closer a light waveguide is located to the image source, the shorter the wavelength of the target light rays coupled-in by the light waveguide. At least in the light waveguide located closest to the image source, the light waveguide body is provided with light extraction elements.

[0107] For example, the image source can be a micro display such as a Micro LED display substrate or a Micro-OLED display substrate.

[0108] FIG. 12 schematically illustrates a side view of a display device according to some embodiments of the present disclosure.

[0109] According to some exemplary embodiments, referring to FIG. 12, the light waveguide device comprises a first light waveguide 100a, a second light waveguide 100b and a third light waveguide 100c, the first light waveguide 100a is located on a side of an emission surface of the image source 200, the second light waveguide 100b is located on a side of the first light waveguide 100a away from the image source 200, and the third light waveguide 100c is located on a side of the second light waveguide 100b away from the image source 200.

[0110] The mixed light rays emitted by the image source 200 comprise first target light rays, second target light rays and third target light rays, for example, the first target light rays comprise blue light, the second target light rays comprise green light, and the third target light rays comprise red light. The first light waveguide 100a comprises a first light waveguide body 111, the first light waveguide 100a is configured to couple-in the first target light rays into the first light waveguide body 111, the second light waveguide 100b comprises a second light waveguide body 112, the second light waveguide 100b is configured to couple-in the second target light rays into the second light waveguide body 112, and the third light waveguide 100c comprises a third light waveguide body 113, the third light waveguide 100c is configured to couple-in the third target light rays into the third light waveguide body 113.

[0111] In order to improve the color purity of the light rays propagating in each light waveguide of the light waveguide device, light extraction elements can be provided in at least one light waveguide, or light extraction elements can be respectively provided in each light waveguide. For example, continuing to refer to FIG. 12, the first light waveguide 100a further comprises first light extraction elements 121 provided on the first light waveguide body 111, the first light extraction elements 121 are configured to transmit the second target light rays and the third target light rays and reflect the first target light rays. The second light waveguide 100b further comprises second light extraction elements 122 provided on the second light waveguide body 112, the second light extraction elements 122 are configured to transmit the first target light rays and the third target light rays and reflect the second target light rays.

[0112] According to some example embodiments, the non-target light rays coupled into the third optical waveguide farthest from the image source are less than those coupled into the second optical waveguide and the first optical waveguide. From the perspective of cost control, the third optical waveguide can not be provided with a light extraction element. Of course, according to actual process requirements, a third light extraction element can also be provided on the third optical waveguide body, which is used to transmit the first target light rays and the second target light rays and reflect the third target light rays.

[0113] According to some example embodiments, referring to FIG. 12, the first light extraction element 121 can be provided on the second surface 111b of the first optical waveguide body 111, or the first light extraction element 121 can also be provided on the first surface 111a of the first optical waveguide body 111, or both the first surface 111a and the second surface 111b are provided with the first light extraction element 121.

[0114] According to some example embodiments, referring to FIG. 12, the second light extraction element 122 can be provided on the second surface 112b of the second optical waveguide body 112, or the second light extraction element 122 can also be provided on the first surface 112a of the second optical waveguide body 112, or both the first surface 112a and the second surface 112b are provided with the second light extraction element 122.

[0115] According to some example embodiments, referring to FIG. 12, the display device further comprises a collimating lens group 300 located between the image source 200 and the optical waveguide device, which is used to collimate the mixed light rays with image information emitted by the image source 200, and convert the light rays of each field of view into parallel light.

[0116] FIG. 13 schematically shows a side view of a display device according to some other embodiments of the present disclosure.

[0117] According to some example embodiments, referring to FIG. 13, the first optical waveguide 100a is the optical waveguide closest to the image source 200. The first light extraction element 121 in the first optical waveguide 100a can be provided on the first surface 111a of the first optical waveguide body 111, i.e., the first light extraction element 121 is provided on the side of the first optical waveguide body 111 away from the second optical waveguide 100b and the third optical waveguide 100c, so as to avoid the light taken out by the first light extraction element 121 from being incident on the second optical waveguide 100b and the third optical waveguide 100c again and causing interference.

[0118] Similarly, when the light extraction element is provided in the optical waveguide farthest from the image source, the light extraction element can be provided on the second surface of the optical waveguide body away from the image source.

[0119] According to some exemplary embodiments, referring back to FIG. 12, the in-coupling grating 140 of the third optical waveguide 100c can be configured to reflect the first target light and the second target light and to in-couple the third target light into the third optical waveguide body 113. For example, the in-coupling grating stripes of the in-coupling grating 140 of the third optical waveguide 100c have a structure of a distributed Bragg reflector, which is designed such that the in-coupling grating 140 of the third optical waveguide 100c reflects the first target light and the second target light and transmits the third target light.

[0120] It should be understood that the in-coupling grating can be configured to reflect the non-target light only in the optical waveguide farthest from the image source, so as to improve the color purity of the optical waveguide without affecting the display effect of the display device.

[0121] FIG. 14 schematically shows a side view of a display device according to yet some embodiments of the present disclosure.

[0122] According to some exemplary embodiments, referring to FIG. 14, the optical waveguide device includes a first optical waveguide 100a and a second optical waveguide 100b, the first optical waveguide 100a is located on one side of the light exit surface of the image source 200, and the second optical waveguide 100b is located on the side of the first optical waveguide 100a away from the image source 200.

[0123] The mixed light emitted by the image source 200 includes the first target light and the second target light, for example, the first target light includes blue light and a part of the green light, and the second target light includes the remaining part of the green light and red light. The first optical waveguide 100a includes a first optical waveguide body 111, and the first optical waveguide 100a is configured to in-couple the first target light into the first optical waveguide body 111. The second optical waveguide 100b includes a second optical waveguide body 112, and the second optical waveguide 100b is configured to in-couple the second target light into the second optical waveguide body 112.

[0124] In order to improve the color purity of the light transmitted in the first optical waveguide 100a and the second optical waveguide 100b respectively, the first optical waveguide 100a further includes a first light extraction element 121 disposed on the first optical waveguide body 111, and the first light extraction element 121 is configured to reflect the first target light and to project the second target light. The in-coupling grating 140 of the second optical waveguide 100b has a structure of a distributed Bragg reflector, and the in-coupling grating 140 of the second optical waveguide 100b is configured to in-couple the second target light and to reflect the first target light.

[0125] According to some exemplary embodiments, the display device is a head-mounted display device, for example, the display device is an augmented reality glasses.

[0126] The display device according to the embodiments of the present disclosure has a wide range of application fields. For example, it can be applied to the field of mass consumption. Through the combination of the head-mounted display device and mobile Internet data, positioning information is obtained, and people can more conveniently obtain surrounding life-related service information, and even big data social relations among interpersonal interactions. For example, it can be applied to the field of medical treatment. Doctors can create virtual coordinates at the part of a patient requiring surgery by wearing the head-mounted display device, and accurately position the part of surgery. For example, it can be applied to the field of entertainment games. Players can make players located at different places join in the game by wearing the head-mounted display device, combining GPS and a gyroscope, taking the real world as the game background, and adding virtual elements to make the game virtual and real.

[0127] It should be understood that the display device according to some example embodiments of the present disclosure has all the features and advantages of the optical waveguide device described above, which can be referred to the description of the optical waveguide device above, and will not be repeated here.

[0128] As used herein, the terms "substantially," "approximately," "about," and other similar terms are used as terms of approximation and not as terms of degree, and they are intended to account for the inherent deviations in measured or calculated values that would be recognized by those of ordinary skill in the art. In view of the process fluctuations, measurement problems, and errors associated with the measurement of a particular quantity (i.e., limitations of the measurement system), etc., "about" or "approximately," as used herein, includes the stated value and means a range of values determined by a person of ordinary skill in the art to be acceptable for the particular value. For example, "about" can mean within one or more standard deviations, or within ±10% or ±5% of the stated value.

[0129] While some embodiments in accordance with the general inventive concept of the present disclosure have been illustrated and described, it is to be understood that changes can be made without departing from the principles and spirit of the general inventive concept of the present disclosure, the scope of which is to be limited only by the claims and their equivalents.

Claims

1. An optical waveguide device, wherein, The optical waveguide device comprises at least one optical waveguide, the optical waveguide comprises a coupling-in region, a coupling-out region and a propagation region between the coupling-in region and the coupling-out region, the optical waveguide comprises an optical waveguide body, the optical waveguide is used for receiving mixed light rays with image information and coupling target light rays from the coupling-in region into the optical waveguide body, the coupled target light rays propagate in the propagation region in a total reflection manner towards the coupling-out region, and finally the target light rays propagating to the coupling-out region are coupled out of the optical waveguide; wherein the optical waveguide body comprises a first surface and a second surface arranged oppositely, and the target light rays are coupled in from the first surface; and At least one of the optical waveguides further comprises a light extraction element, the light extraction element is arranged on the first surface and / or the second surface of the optical waveguide body, at least a part of the light extraction element is located in the propagation region, and the light extraction element is used for transmitting non-target light rays and reflecting target light rays.

2. The optical waveguide device of claim 1, wherein, The light extraction element comprises a distributed Bragg reflector, which is used for transmitting non-target light rays and reflecting target light rays.

3. The optical waveguide device according to claim 1 or 2, wherein, At least one of the optical waveguides further comprises a light absorption element arranged on a side of the light extraction element away from the optical waveguide body, and the light absorption element is used for absorbing non-target light rays.

4. The optical waveguide device of claim 3, wherein, The material of the light absorption element comprises a black matrix material.

5. The optical waveguide device according to any one of claims 1 to 4, wherein, The optical waveguide further comprises a coupling-in grating, a coupling-out grating and a turning grating arranged on the first surface of the optical waveguide body, the coupling-in grating is located in the coupling-in region, the coupling-out grating is located in the coupling-out region, and the turning grating is located in the propagation region. Wherein, the orthographic projection of the turning grating on the optical waveguide body is located on one side of the orthographic projection of the coupling-in grating on the optical waveguide body along a second direction, and the orthographic projection of the turning grating on the optical waveguide body is located on one side of the orthographic projection of the coupling-out grating on the optical waveguide body along a first direction, and the first direction intersects the second direction.

6. The optical waveguide device of claim 5, wherein, The light extraction element comprises a first light extraction element and / or a second light extraction element; Wherein, along the propagation direction of the target light rays, the orthographic projection of the first light extraction element on the optical waveguide body is located between the orthographic projection of the coupling-in grating on the optical waveguide body and the orthographic projection of the turning grating on the optical waveguide body; and Along the propagation direction of the target light rays, the orthographic projection of the second light extraction element on the optical waveguide body is located between the orthographic projection of the coupling-out grating on the optical waveguide body and the orthographic projection of the turning grating on the optical waveguide body.

7. The optical waveguide device of claim 6, wherein, The orthographic projection of the first light extraction element on the optical waveguide body is tangent to the orthographic projection of the coupling-in grating on the optical waveguide body, and / or the orthographic projection of the first light extraction element on the optical waveguide body is tangent to the orthographic projection of the turning grating on the optical waveguide body; and ​ A projection of the second light extraction element on the optical waveguide body is tangential to a projection of the out-coupling grating on the optical waveguide body, and / or a projection of the second light extraction element on the optical waveguide body is tangential to a projection of the turning grating on the optical waveguide body.

8. The optical waveguide device of claim 6, wherein, A projection of the first light extraction element on the optical waveguide body is spaced apart from a projection of the in-coupling grating on the optical waveguide body, and / or a projection of the first light extraction element on the optical waveguide body is spaced apart from a projection of the turning grating on the optical waveguide body. A projection of the second light extraction element on the optical waveguide body is spaced apart from a projection of the out-coupling grating on the optical waveguide body, and / or a projection of the second light extraction element on the optical waveguide body is spaced apart from a projection of the turning grating on the optical waveguide body. A size of a projection of the first light extraction element on the optical waveguide body along the first direction is greater than or equal to a size of a projection of the in-coupling grating on the optical waveguide body along the first direction, and / or a size of a projection of the first light extraction element on the optical waveguide body along the first direction is greater than or equal to a size of a projection of the turning grating on the optical waveguide body along the first direction.

9. An optical waveguide device according to any of claims 6-8, wherein, A size of a projection of the second light extraction element on the optical waveguide body along the second direction is greater than a size of a projection of the out-coupling grating on the optical waveguide body along the second direction, and / or a size of a projection of the second light extraction element on the optical waveguide body along the second direction is greater than a size of a projection of the turning grating on the optical waveguide body along the second direction. In at least one optical waveguide, the in-coupling grating is configured to in-couple target light rays and reflect non-target light rays. The in-coupling grating comprises a plurality of in-coupling grating bars arranged at intervals, the in-coupling grating bars having a structure of distributed Bragg reflector, and the in-coupling grating bars are configured to reflect non-target light rays and transmit target light rays.

10. The optical waveguide device according to any of claims 5-9, wherein, The display device comprises an image source and the optical waveguide device according to any one of claims 1-11.

11. The optical waveguide device of claim 10, wherein, The image source is configured to emit mixed light rays having image information; and 12. A display device, wherein, The optical waveguide device comprises at least two optical waveguides arranged on one side of an emission surface of the image source and along an emission direction of the image source. Different optical waveguides in-couple target light rays having different wavelengths, and the closer to the image source, the shorter the wavelength of the in-coupled target light rays. At least in the optical waveguide closest to the image source, the optical waveguide body is provided with the light extraction element.

13. The display device of claim 12, wherein, In the optical waveguide closest to the image source, the light extraction element is arranged on the first surface of the optical waveguide body; and / or In the optical waveguide farthest from the image source, the light extraction element is arranged on the second surface of the optical waveguide body.

14. A display device according to claim 12 or 13, wherein, The optical waveguide comprises an in-coupling grating arranged on a first surface of the optical waveguide body and located in an in-coupling region. ​ 15. An optical waveguide device according to any of claims 12-14, wherein, ​ In the light waveguide farthest from the image source, the in-coupling grating is configured to in-couple the target light rays and reflect the non-target light rays.

Images