Display device, head-up display, and traffic device

Abstract

Embodiments of the present disclosure provide a display device, a head-up display and a traffic device. The display device comprises a display panel and a backlight source. The backlight source is located at the back side of the display panel, and the backlight source comprises a light source part and a light waveguide element. The light waveguide element comprises an out-light surface and a trans-reflection element array, and the trans-reflection element array comprises a plurality of trans-reflection elements. The light source part is configured to make the light rays emitted by the light source part undergo multiple total reflections at least at the out-light surface of the light waveguide element and sequentially propagate to the plurality of trans-reflection elements of the trans-reflection element array. A part of the light rays propagating to each trans-reflection element of the trans-reflection element array is reflected by the trans-reflection element out of the out-light surface of the light waveguide element and then transmits through the display panel. Another part of the light rays propagating to each trans-reflection element of the trans-reflection element array transmits through the trans-reflection element and then continues to propagate in the light waveguide element. By arranging the light waveguide element in the backlight source, the display effect and portability of the display device can be improved.

Description

TECHNICAL FIELD

[0001] The display device, head-up display and traffic equipment of at least one embodiment of the present disclosure relate. BACKGROUND

[0002] At present, users have higher and higher requirements on the use of display devices such as those including backlights, and more requirements on the display effect and portability and other performances of the display devices, and the backlights in the display devices have a certain degree of influence on the display effect and portability and other performances of the display devices. SUMMARY

[0003] The display device, head-up display and traffic equipment of at least one embodiment of the present disclosure relate.

[0004] The display device of at least one embodiment of the present disclosure comprises a display panel comprising a display surface and a back side opposite to the display surface, and a backlight source located at the back side of the display panel. The backlight source comprises a light waveguide element comprising an out-coupling surface and a transreflective element array comprising a plurality of transreflective elements, and a light source part configured to make the light rays emitted by the light source part undergo multiple total reflections at least at the out-coupling surface of the light waveguide element and sequentially propagate to the plurality of transreflective elements of the transreflective element array after entering the light waveguide element, a part of the light rays propagating to each transreflective element of the transreflective element array being reflected by the transreflective element out of the out-coupling surface of the light waveguide element and then transmitted through the display panel, and another part of the light rays propagating to each transreflective element of the transreflective element array continuing to propagate in the light waveguide element after being transmitted through the transreflective element.

[0005] The head-up display of at least one embodiment of the present disclosure comprises any display device of the present disclosure, and a reflective imaging part located at the light exit side of the display device and configured to reflect the light rays emitted by the display device to the viewing area of the head-up display.

[0006] The traffic equipment of at least one embodiment of the present disclosure comprises any head-up display of the present disclosure.

[0007] For example, in the embodiments of the present disclosure, the light waveguide element further comprises a waveguide medium, and the light rays emitted by the light source part enter the waveguide medium and propagate by total reflection in the waveguide medium.

[0008] For example, in the embodiments of the present disclosure, the included angle between each transreflective element and the out-coupling surface is a first included angle, and the sum of the first included angle and the total reflection critical angle of the total reflection of the light rays at the out-coupling surface is in the range of 60°-120°.

[0009] For example, in the embodiments of the present disclosure, the light waveguide element includes a plurality of sub-light waveguide elements, and the array of transmissive-reflection elements includes a plurality of sub-arrays of transmissive-reflection elements respectively located in the plurality of sub-light waveguide elements; the backlight source further includes a light splitting element configured to split the light emitted by the light source portion and directed towards the light waveguide element into a plurality of sub-beams and make the plurality of sub-beams respectively enter the plurality of sub-light waveguide elements, and each sub-beam entering each sub-light waveguide element is reflected out of the light emitting surface of the light waveguide element by the array of transmissive-reflection elements located in each sub-light waveguide element.

[0010] For example, in the embodiments of the present disclosure, the plurality of sub-light waveguide elements are arranged in a direction perpendicular to the display surface of the display panel, or the plurality of sub-light waveguide elements are arranged in a direction parallel to the display surface; the plurality of sub-light waveguide elements include a first sub-light waveguide element and a second sub-light waveguide element.

[0011] For example, in the embodiments of the present disclosure, the light emitted by the light source portion and directed towards the light waveguide element includes first characteristic light and second characteristic light with different characteristics, and the light splitting element is configured to perform light splitting processing on the light emitted by the light source portion and directed towards the light waveguide element, so that the first characteristic light obtained by the light splitting processing is incident on the first sub-light waveguide element, and the second characteristic light obtained by the light splitting processing is incident on the second sub-light waveguide element.

[0012] For example, in the embodiments of the present disclosure, the first characteristic light and the second characteristic light are first polarized light and second polarized light with different polarization states, respectively; or the first characteristic light and the second characteristic light are first color light and second color light with different colors, respectively.

[0013] For example, in the embodiments of the present disclosure, the plurality of sub-beams obtained by performing the light splitting processing on the light include the first color light, the second color light, and third color light configured to enter one of the first sub-light waveguide element and the second sub-light waveguide element; or the plurality of sub-beams include the first color light, the second color light, and third color light, and the plurality of sub-light waveguide elements further include a third sub-light waveguide element, the third color light is configured to enter the third sub-light waveguide element, and is reflected out of the third sub-light waveguide element by the array of transmissive-reflection elements located in the third sub-light waveguide element.

[0014] For example, in the embodiments of the present disclosure, the transreflective element in the first sub-optical waveguide element is a transreflective element with a reflectivity to the first characteristic light greater than a reflectivity to the second characteristic light, and the transreflective element in the second sub-optical waveguide element is a transreflective element with a reflectivity to the second characteristic light greater than a reflectivity to the first characteristic light.

[0015] For example, in the embodiments of the present disclosure, the light splitting element includes a polarization light splitting element configured to reflect one of the first polarized light and the second polarized light and transmit the other of the first polarized light and the second polarized light, and a reflective element configured to reflect one of the first polarized light and the second polarized light.

[0016] For example, in the embodiments of the present disclosure, the reflectivity of the transreflective elements arranged in sequence along the extension direction of the light exit surface in the transreflective element array gradually increases or gradually increases regionally in the propagation direction of the light rays, and / or the arrangement density of the transreflective elements arranged in sequence along the extension direction of the light exit surface in the transreflective element array gradually increases or gradually increases regionally.

[0017] For example, in the embodiments of the present disclosure, at least one transreflective element in the transreflective element array includes a selective transmission film, the light entering the optical waveguide element includes first light and second light with different characteristics, the selective transmission film is configured to have a reflectivity to the first light greater than a reflectivity to the second light and a transmissivity to the second light greater than a transmissivity to the first light.

[0018] For example, in the embodiments of the present disclosure, the transreflective element array includes a first transreflective element group and a second transreflective element group arranged along the extension direction of the light exit surface, each transreflective element group includes transreflective elements arranged along the extension direction of the light exit surface, the inclination direction of the transreflective elements of the first transreflective element group relative to the light exit surface is non-parallel to the inclination direction of the transreflective elements of the second transreflective element group relative to the light exit surface, the light source portion includes a first light source portion and a second light source portion, the first light source portion and the second light source portion are respectively located on both sides of the transreflective element array along the extension direction of the light exit surface, the first transreflective element group is configured to reflect the light rays emitted by the first light source portion into the optical waveguide element out of the optical waveguide element, and the second transreflective element group is configured to reflect the light rays emitted by the second light source portion into the optical waveguide element out of the optical waveguide element; or the light source portion is located between the first transreflective element group and the second transreflective element group in the extension direction of the light exit surface.

[0019] For example, in the embodiments of the present disclosure, the array of transreflective elements includes at least some of the plurality of transreflective elements arranged in sequence along a first direction and extending along a second direction intersecting the first direction, and the light source portion includes a plurality of sub-light sources arranged along the second direction, the plurality of sub-light sources configured to emit light rays into the at least some of the transreflective elements.

[0020] For example, in the embodiments of the present disclosure, the array of transreflective elements includes at least some of the plurality of transreflective elements arranged in sequence along a first direction and extending along a second direction intersecting the first direction, and the light source portion includes a plurality of sub-light sources arranged along the second direction, the plurality of sub-light sources configured to emit light rays into the at least some of the transreflective elements.

[0021] For example, in the embodiments of the present disclosure, the light rays emitted by the light source portion include first polarized light and second polarized light having different polarization states, and the display panel is configured to generate image light rays using the first polarized light or the second polarized light. The display device further includes a light conversion device, the light conversion device including a beam splitting element, a direction changing element, and a polarization conversion element, the beam splitting element located on a side of the display panel facing the light waveguide element and configured to split light rays incident on the beam splitting element into first polarized light beams and second polarized light beams having different polarization states, the first polarized light beams being directed toward the display panel, and the second polarized light beams being directed toward the direction changing element; the direction changing element is configured to change the propagation direction of light beams incident on the direction changing element so that they are directed toward the display panel; and the polarization conversion element is configured to convert polarized light beams in the first polarized light beams and the second polarized light beams that cannot be utilized by the display panel into polarized light beams that can be utilized by the display panel before reaching the display panel.

[0022] For example, in the embodiments of the present disclosure, the light conversion device is configured to recycle light emitted by the light source portion and feed the recycled light into the light waveguide element, and / or recycle light emitted by the light waveguide element and feed the recycled light into the display panel.

[0023] For example, in the embodiments of the present disclosure, the display device further includes at least one light diffusion element located on at least one of the display surface side and the back side of the display panel and configured to diffuse light rays emitted by at least one of the display panel and the light waveguide element.

[0024] For example, in the embodiments of the present disclosure, the display device further comprises a light converging element located between the light waveguide element and the display panel and configured to converge the light rays emitted from the light waveguide element and then make the converged light rays shoot towards the at least one light diffusion element.

[0025] For example, in the embodiments of the present disclosure, the light converging element comprises at least one lens.

[0026] For example, in the embodiments of the present disclosure, the light converging element and the light waveguide element are in an integrated structure, and a transparent medium layer is arranged between the light converging element and the light waveguide element, the refractive index of the transparent medium layer being less than the refractive index of the light waveguide element.

[0027] For example, in the embodiments of the present disclosure, the light emitting surface of the light waveguide element and the display surface of the display panel are arranged in a stacking manner in a direction perpendicular to the display surface, and the light source part is located at the side of the light waveguide element.

[0028] For example, in the embodiments of the present disclosure, the backlight source comprises a light waveguide plate, the light waveguide plate comprising a light uniformizing part and the light waveguide element, the light rays emitted by the light source part entering the light waveguide element after multiple total reflections in the light uniformizing part, the light waveguide plate being in an integrated structure.

[0029] For example, in the embodiments of the present disclosure, the reflection imaging part comprises a windshield of the traffic equipment.

[0030] For example, in the embodiments of the present disclosure, the backlight source comprises a light waveguide plate, the light waveguide plate comprising a light uniformizing part and a light waveguide element, the light waveguide element comprising a light emitting surface, the light uniformizing part and the light waveguide element being arranged in sequence in a direction perpendicular to the light emitting surface; the backlight source further comprises a light source part configured to make the light rays emitted by the light source part enter the light waveguide element after multiple total reflections in the light uniformizing part, and then be emitted from the light emitting surface of the light waveguide element.

[0031] For example, in the embodiments of the present disclosure, the light emitted by the light source part includes first polarized light and second polarized light with different polarization states; the light waveguide element includes a light out-coupling part. The light source part is configured to make the light emitted by the light source part reflectively propagate in the light waveguide element after entering the light waveguide element, and the light out-coupling part is configured to couple out the light reflectively propagating in the light waveguide element; the light out-coupling part includes a first light out-coupling part and a second light out-coupling part, the first light out-coupling part is configured to couple out the first polarized light entering the light waveguide element; the backlight source further includes a polarization conversion structure, the polarization conversion structure is configured to convert the second polarized light entering the light waveguide element into first polarized light, and the second light out-coupling part is configured to couple out the converted first polarized light after the polarization conversion structure converts the second polarized light entering the light waveguide element into first polarized light; or the second light out-coupling part is configured to couple out the second polarized light entering the light waveguide element to the polarization conversion structure, so that the coupled-out second polarized light is converted into the first polarized light by the polarization conversion structure. BRIEF DESCRIPTION OF DRAWINGS

[0032] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only related to some embodiments of the present disclosure, and not limited to the present disclosure.

[0033] FIG. 1A A partial cross-sectional structure schematic diagram of a display device according to an example provided by the embodiments of the present disclosure;

[0034] FIG. 1B A partial cross-sectional structure schematic diagram of a display device according to an example provided by the embodiments of the present disclosure;

[0035] FIG. 2 A partial cross-sectional structure schematic diagram of a display device according to an example provided by the embodiments of the present disclosure; FIG. 1A A planar structure schematic diagram of a backlight source in the example shown;

[0036] FIG. 3 A planar structure schematic diagram of another backlight source in the example shown; FIG. 1A A planar structure schematic diagram of another backlight source in the example shown;

[0037] FIG. 4A A planar structure schematic diagram of another backlight source in the example shown; FIG. 1A A planar structure schematic diagram of another backlight source in the example shown;

[0038] FIG. 4B A planar structure schematic diagram of another backlight source in the example shown; FIG. 1A A planar structure schematic diagram of another backlight source in the example shown;

[0039] FIG. 5 A planar structure schematic diagram of another backlight source in the example shown; FIG. 1AAnother plan view schematic of a backlight in the illustrated example;

[0040] FIG. 6 For an example in which light rays emerging from the array of transflective elements are not normal to the major surfaces of the waveguide medium;

[0041] FIG. 7 Schematic of a partial structure of a backlight in another example according to embodiments of the present disclosure;

[0042] FIG. 8 Schematic of a partial structure of a backlight in another example according to embodiments of the present disclosure;

[0043] FIG. 9 Schematic of a partial structure of a backlight in another example according to embodiments of the present disclosure;

[0044] FIG. 10 Schematic of a partial structure of a backlight in another example according to embodiments of the present disclosure;

[0045] FIG. 11 Schematic of a partial structure of a backlight in another example according to embodiments of the present disclosure;

[0046] FIG. 12 Schematic of a partial structure of a backlight in another example according to embodiments of the present disclosure;

[0047] FIG. 13 Schematic of a partial structure of a backlight in another example according to embodiments of the present disclosure;

[0048] FIG. 14 Schematic of a partial structure of a backlight in an example according to another embodiment of the present disclosure;

[0049] FIG. 15 Schematic of a partial structure of a backlight in an example according to another embodiment of the present disclosure;

[0050] FIG. 16 For FIG. 15 The backlight illustrated is an example;

[0051] FIG. 17 Schematic of a partial structure of a backlight in another example according to another embodiment of the present disclosure;

[0052] FIG. 18 Schematic of a partial structure of a backlight in another example according to another embodiment of the present disclosure;

[0053] FIG. 19 For FIG. 18 The backlight illustrated is an example;

[0054] FIG. 20 A partial structural schematic diagram of a backlight according to another example of another embodiment of the present disclosure is provided as follows;

[0055] FIG. 21 A partial structural schematic diagram of a backlight according to another example of another embodiment of the present disclosure is provided as follows; FIG. 20 A partial structural schematic diagram of a backlight according to another example of another embodiment of the present disclosure is provided as follows;

[0056] FIG. 22 A partial structural schematic diagram of a backlight according to another example of another embodiment of the present disclosure is provided as follows;

[0057] FIG. 23 A partial structural schematic diagram of a backlight according to another example of another embodiment of the present disclosure is provided as follows; FIG. 22 A partial structural schematic diagram of a backlight according to another example of another embodiment of the present disclosure is provided as follows;

[0058] FIG. 24 A partial structural schematic diagram of a backlight according to another example of another embodiment of the present disclosure is provided as follows;

[0059] FIG. 25 A partial structural schematic diagram of a display device according to another example of another embodiment of the present disclosure is provided as follows;

[0060] FIG. 26 A partial structural schematic diagram of a display device according to another example of another embodiment of the present disclosure is provided as follows;

[0061] FIG. 27 A partial structural schematic diagram of a display device according to another example of another embodiment of the present disclosure is provided as follows;

[0062] FIG. 28 A partial structural schematic diagram of a display device according to another example of another embodiment of the present disclosure is provided as follows;

[0063] FIG. 29 A partial structural schematic diagram of a display device according to another example of another embodiment of the present disclosure is provided as follows;

[0064] FIG. 30 A partial structural schematic diagram of a display device according to another example of another embodiment of the present disclosure is provided as follows;

[0065] FIG. 31 A partial structural schematic diagram of a display device according to another example of another embodiment of the present disclosure is provided as follows;

[0066] FIG. 32 A partial structural schematic diagram of a head-up display according to another embodiment of the present disclosure is provided as follows; and

[0067] FIG. 33 An exemplary block diagram of a traffic device according to another embodiment of the present disclosure is provided as follows. DETAILED DESCRIPTION

[0068] In order to make the objects, technical solutions and advantages of the embodiments of the present disclosure clearer, the following will be combined with the drawings of the embodiments of the present disclosure to make a clear and complete description of the technical solutions of the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, rather than all the embodiments. Based on the described embodiments of the present disclosure, all other embodiments obtained by a person of ordinary skill in the art without creative effort fall within the protection scope of the present disclosure.

[0069] Unless otherwise defined, technical terms or scientific terms used in the present disclosure shall have the ordinary meaning understood by a person of ordinary skill in the art to which the present disclosure pertains. The terms "first", "second" and similar terms used in the present disclosure do not denote any order, quantity or importance, but are used to distinguish different components. The terms "comprise", "comprise" and similar terms mean that the elements or objects before the terms encompass the elements or objects listed after the terms and their equivalents, and do not exclude other elements or objects.

[0070] In research, the inventors of the present application found that the backlight source in a general display device needs to be provided with a longer light mixing distance to ensure the uniformity of the light output, and the longer light mixing distance of the backlight source will result in a larger thickness of the display device, affecting the portability of the display device.

[0071] Embodiments of the present disclosure provide a display device, a head-up display and a traffic equipment. The display device comprises a display panel and a backlight source. The display panel comprises a display surface and a back side opposite to the display surface; the backlight source is located at the back side of the display panel. The backlight source comprises a light waveguide element, the light waveguide element comprises an output surface and a transreflective element array, the transreflective element array comprises a plurality of transreflective elements, the backlight source further comprises a light source part, the light source part is configured to make the light rays emitted thereby undergo multiple total reflections at least at the output surface of the light waveguide element and sequentially propagate to the plurality of transreflective elements of the transreflective element array, a part of the light rays propagating to each transreflective element of the transreflective element array is reflected out of the output surface of the light waveguide element by the transreflective element and then transmits through the display panel, another part of the light rays propagating to each transreflective element of the transreflective element array transmits through the transreflective element and then continues to propagate in the light waveguide element. In the display device provided by the present disclosure, by providing the light waveguide element in the backlight source, the thickness of the backlight source and the space occupied in the display device can be reduced while ensuring the uniformity of the light output, so as to improve the display effect and portability of the display device.

[0072] The display device, the head-up display and the traffic equipment provided by the embodiments of the present disclosure will be described below in combination with the drawings.

[0073] FIG. 1A A partial cross-sectional structure schematic diagram of the display device provided according to an example of the embodiments of the present disclosure is shown in FIG. 1. As shown in FIG. 1, the display device comprises a display panel 100 and a backlight source 200.FIG. 1A As shown, the display device includes a display panel 10 and a backlight source 20. The display panel 10 includes a display surface 10-01 and a back side 10-02 opposite to the display surface 10-01. The backlight source 20 is located on the back side 10-02 of the display panel 10. For example, light emitted by the backlight source 20 passes through the display panel 10 and is emitted toward the observation area 30. For example, the side of the display panel 10 facing the backlight source 20 is the non-display side, and the side of the display panel 10 away from the backlight source 20 is the display side. The observation area 30 is located on the display side of the display panel 10, which is the side where the user can view the displayed image. For example, the observation area 30 and the backlight source 20 are located on both sides of the display panel 10.

[0074] like FIG. 1A As shown, the backlight 20 includes a light source unit 100 and an optical waveguide element 200. The optical waveguide element 200 includes a light-emitting surface 211 and a transflective element array 220. The transflective element array 220 includes a plurality of transflective elements 221. The light source unit 100 is configured such that, after entering the optical waveguide element 200, light emitted by the light source unit 100 undergoes multiple total internal reflections at least at the light-emitting surface 211 of the optical waveguide element 200 and sequentially propagates to the plurality of transflective elements 221 of the transflective element array 220. A portion of the light propagating to each transflective element 221 of the transflective element array 220 is reflected by the transflective element 221 out of the light-emitting surface 211 of the optical waveguide element 200 and then transmits through the display panel 10. Another portion of the light propagating to each transflective element 221 of the transflective element array 220 transmits through the transflective element 221 and continues to propagate within the optical waveguide element 200.

[0075] In the embodiment of the present disclosure, by providing an optical waveguide element in the backlight source, the thickness of the backlight source and the space occupied in the display device can be reduced while the brightness of the light output is uniform, thereby improving the display effect and portability of the display device.

[0076] For example, FIG. 1A As shown, the optical waveguide element 200 further includes a waveguide medium 210. Light emitted by the light source unit 100 enters the waveguide medium 210 and propagates by total reflection in the waveguide medium 210. A portion of the light propagating to each transflective element 221 of the transflective element array 220 is reflected by the transflective element 221 and exits the optical waveguide element 200, while the remaining portion of the light continues to propagate by total reflection after being transmitted through the transflective element 221.

[0077] For example, the transflective element array 220 includes multiple transflective elements 221. Light propagating through each transflective element 221 is transmitted and reflected by the transflective element 221. For example, a portion of light incident on the surface of a transflective element 221 is reflected by the transflective element 221 and exits the optical waveguide element 200, while another portion of the light is transmitted through the transflective element 221 and then transmitted and reflected by the next transflective element 221. The transmitted light then continues to be reflected and propagates through the transflective element 221 to the transflective element 221 furthest from the light source 100 (e.g., the light is transmitted through multiple transflective elements in sequence until it reaches the transflective element furthest from the light source). For example, all or part of the light propagating through the transflective element furthest from the light source may be reflected by the transflective element, but this is not a limitation of the presently disclosed embodiments.

[0078] For example, FIG. 1A As shown, the light emitting surface 211 of the optical waveguide element 200 is stacked with the display surface 10-01 of the display panel 10 in a direction perpendicular to the display surface 10-01, and the light source unit 100 is located to the side of the optical waveguide element 200. In the embodiment of the present disclosure, the optical waveguide element is located below the display panel and the light source unit is located to the side of the optical waveguide element as an example, but the present invention is not limited thereto. For example, the display panel 10 includes a display surface for displaying an image, and the light emitting surface of the optical waveguide element 200 is located on a side of the display panel 10 away from the display surface, such as below the display panel 10, rather than to the side of the display panel 10; the light source unit 100 is located to the side of the optical waveguide element 200, that is, the backlight source 20 is an edge-lit backlight.

[0079] For example, the light source unit 100 is configured to output collimated light. For example, the light source unit 100 includes a light source and a collimating element. The collimating element is configured to convert light emitted by the light source, which has a certain divergence angle, into collimated light. "Collimated light" here refers to parallel or nearly parallel light. The light source unit 100 outputs collimated light so that as much light as possible meets the total internal reflection condition and is thus utilized.

[0080] For example, the light source can be a monochromatic light source or a mixed color light source, such as a red monochromatic light source, a green monochromatic light source, a blue monochromatic light source, or a white mixed color light source. The monochromatic light sources can ultimately form a monochromatic image, while the mixed color light sources can form a color image. For example, the light source can be a laser light source or a light emitting diode (LED) light source. For example, the light source unit can include one light source or multiple light sources.

[0081] For example, the collimating element may include a convex lens, a concave lens, or a Fresnel lens, or any combination of the above lenses.

[0082] For example, the collimating element can include a convex lens, and the light source can be disposed near a focal point of the convex lens, so that the divergent light emitted by the light source can be converted into parallel or nearly parallel collimated light rays after passing through the lens.

[0083] For example, FIG. 2 For example, FIG. 1A A schematic diagram of a planar structure of another backlight according to the example shown in FIG. 1. As shown in FIG. 2, the light source of the light source part 100 can include a plurality of light sources 101 arranged along the second direction, and the plurality of light sources 101 can be configured to emit light rays into the at least partial light-transmitting and light-reflecting element array 220. FIG. 2 For example, the light source of the light source part 100 can include a plurality of sub-light sources 101 arranged along the second direction, and the plurality of sub-light sources 101 can be configured to emit light rays into the at least partial light-transmitting and light-reflecting element array 220.

[0084] For example, FIG. 3 A schematic diagram of a planar structure of another backlight according to the example shown in FIG. 1. As shown in FIG. 2, the light source of the light source part 100 can include a plurality of light sources 101 arranged along the second direction, and the plurality of light sources 101 can be configured to emit light rays into the at least partial light-transmitting and light-reflecting element array 220. FIG. 1A For example, the light source of the light source part 100 can include a plurality of sub-light sources 101 arranged along the second direction, and the plurality of sub-light sources 101 can be configured to emit light rays into the at least partial light-transmitting and light-reflecting element array 220. FIG. 3 For example, as shown in FIG. 3, the light source of the light source part 100 can include a plurality of sub-light sources 101 arranged along the second direction, and the plurality of sub-light sources 101 can be configured to emit light rays into the at least partial light-transmitting and light-reflecting element array 220.

[0085] For example, the light source of the light source part 100 can include a plurality of sub-light sources 101 arranged along the second direction, and the plurality of sub-light sources 101 can be configured to emit light rays into the at least partial light-transmitting and light-reflecting element array 220. FIG. 3 For example, the light source of the light source part 100 can include a plurality of sub-light sources 101 arranged along the second direction, and the plurality of sub-light sources 101 can be configured to emit light rays into the at least partial light-transmitting and light-reflecting element array 220.

[0086] For example, FIG. 4A A schematic diagram of a planar structure of another backlight according to the example shown in FIG. 1. As shown in FIG. 2, the light source of the light source part 100 can include a plurality of light sources 101 arranged along the second direction, and the plurality of light sources 101 can be configured to emit light rays into the at least partial light-transmitting and light-reflecting element array 220. FIG. 1A For example, the light source of the light source part 100 can include a plurality of sub-light sources 101 arranged along the second direction, and the plurality of sub-light sources 101 can be configured to emit light rays into the at least partial light-transmitting and light-reflecting element array 220. FIG. 4A For example, the light source of the light source part 100 can include a plurality of sub-light sources 101 arranged along the second direction, and the plurality of sub-light sources 101 can be configured to emit light rays into the at least partial light-transmitting and light-reflecting element array 220.

[0087] For example, the light source included in the light source unit 100 may be a single point light source 101 that emits a single point light beam. For example, the point light source may be a laser light source, which has a very small beam cross-section and highly concentrated light energy. Therefore, the light beam emitted by the point light source can be expanded in one dimension. The expanded light then passes through the waveguide medium and the transflective element array to transform into a surface light source.

[0088] For example, FIG. 4A As shown, the light emitted by the point light source 101 first passes through the multiple beam expanders 102 to be extended and expanded in the second direction, and then is transmitted along the first direction to the transflective element array 220. For example, when the light emitted by the point light source 101 is extended and expanded, it can propagate along any one or more propagation modes of a reflection path, a total reflection path, and a straight path.

[0089] For example, the beam expander 102 may be a grating, or may be another array of transflective elements, which is not limited in the embodiment of the present disclosure.

[0090] For example, the light source may be configured to guide light into the optical waveguide element in a side-entry manner, thereby avoiding further increasing the thickness of the backlight source.

[0091] For example, when the backlight source provided in the embodiment of the present disclosure is applied to a display device that requires higher brightness, such as a head-up display, a light source that emits a one-dimensional light beam (for example, a light strip or multiple linearly arranged point light sources) can provide a higher brightness for the backlight source, and the solution is simple and easy to implement.

[0092] For example, FIG. 4B Schematic diagram of the structure of another backlight source. FIG. 4B The backlight shown is FIG. 4A The backlight shown differs in that the beam expander is located in the optical waveguide element.

[0093] For example, FIG. 1A As shown, the optical waveguide element 200 further includes a light coupling portion 230 located on the side of the transflective element array 220 facing the light source unit 100. The light coupling portion 230 is configured to ensure that light entering the optical waveguide element 200 satisfies the total reflection condition and propagates through total reflection in the waveguide medium 210. The embodiments of the present disclosure are not limited to the optical waveguide element including the light coupling portion. For example, the optical waveguide element may not include the light coupling portion. When the angle of light incident on the waveguide medium satisfies the total reflection condition, the light can achieve total reflection propagation in the waveguide medium.

[0094] For example, the refractive index of the waveguide medium is n1, the refractive index of the optically sparse medium (such as air) outside the waveguide medium is n2, and the incident angle of the light when entering the waveguide medium or the incident angle after passing through the optical coupling part is not less than the critical angle of total reflection arcsin(n2 / n1), then the light meets the total reflection condition.

[0095] For example, the light in-coupling part 230 in the embodiments of the present disclosure can include at least one of a surface grating, a volume grating, a blazed grating, a prism, and a reflective structure, and can in-couple the light emitted by the light source into the waveguide medium by at least one of reflection, refraction, and diffraction effects, so as to satisfy the total internal reflection condition and then be conducted.

[0096] For example, as shown in FIG. 2A, the light waveguide element 200 includes two first and second main surfaces 211 and 212 opposite to each other, and the light in-coupling part 230 can be arranged on the first and second main surfaces 211 and 212, or can be arranged on the side surface connecting the two main surfaces. For example, the two main surfaces of the light waveguide element can also be referred to as two main surfaces of the waveguide medium. For example, the trans-reflector array 220 is located between the first and second main surfaces. For example, the light rays propagate by at least total reflection on the first and / or second main surfaces, and there can also be partial non-total reflection, such as specular reflection. FIG. 1A For example, when the light waveguide element includes a plurality of sub-light waveguide elements, for example, the plurality of sub-light waveguide elements are arranged in a vertical direction perpendicular to the first main surface, the upper surface of the uppermost sub-light waveguide element is the first main surface, and the lower surface of the lowermost sub-light waveguide element is the second main surface.

[0097] For example, the first and second main surfaces 211 and 212 include an upper surface 211 close to the display panel 10 and a lower surface 212 away from the display panel 10, and the light in-coupling part 230 can be arranged on the upper surface 211 or the lower surface 212 and located on the side of the trans-reflector array 220 facing the light source part 100. For example, the first direction (X direction) and the second direction (Z direction) are parallel to the above-mentioned main surfaces.

[0098] For example, the waveguide medium 210 is made of a material that can realize the waveguide function, and is generally a transparent material with a refractive index greater than 1. For example, the material of the waveguide medium 210 can include one or more of silicon dioxide, lithium niobate, silicon-on-insulator (SOI), a polymer, a III-V semiconductor compound, and glass.

[0099] For example, the waveguide medium 210 can be a planar substrate, a strip-shaped substrate, a ridge-type substrate, etc. For example, in at least one example of the embodiments of the present disclosure, the waveguide medium adopts a planar substrate to form a uniform surface light source.

[0100] For example, as shown in FIG. 2A, the light waveguide element 200 includes two first and second main surfaces 211 and 212 opposite to each other, and the light in-coupling part 230 can be arranged on the first and second main surfaces 211 and 212, or can be arranged on the side surface connecting the two main surfaces. For example, the two main surfaces of the light waveguide element can also be referred to as two main surfaces of the waveguide medium. For example, the trans-reflector array 220 is located between the first and second main surfaces. For example, the light rays propagate by at least total reflection on the first and / or second main surfaces, and there can also be partial non-total reflection, such as specular reflection.

[0101] FIG. 1A to FIG. 3 For example, as shown in FIG. 2A, the trans-reflector array 220 includes a plurality of trans-reflectors 221 arranged in the direction of total reflection of the light rays. The above-mentioned "direction of total reflection of the light rays" can refer to the overall (macroscopic) direction of the light rays, for example, here it refers to the direction of the light rays propagating by total reflection on the first and / or second main surfaces. FIG. 1A ​In the illustrated first direction (i.e., the X direction), the light rays entering the optical waveguide element 200 undergo total internal reflection at the two major surfaces of the waveguide medium 210, so that the light rays propagate as a whole in the X direction to the array of transreflective elements 220.

[0102] For example, as shown in FIG. 2B, the transreflective element 221 is configured to transmit the light rays while reflecting the light rays. For example, when the light rays that undergo total reflection transmission in the waveguide medium 210 reach the transreflective element 221, the light rays are reflected at the transreflective element 221, the angle of the reflected light rays no longer satisfies the total reflection condition, and the light rays are then emitted; the transmitted light rays continue to propagate along the total reflection path, continue to be transmitted to the next transreflective element 221, and continue to be reflected and transmitted, the light rays reflected by the next transreflective element 221 are emitted from the optical waveguide element 200, and the light rays transmitted by the next transreflective element 221 continue to propagate along the total reflection path; and the process is repeated in sequence until the light rays reach the last transreflective element 221. FIG. 1A to FIG. 3 For example, as shown in FIG. 2B, the transreflective element 221 can be disposed in the waveguide medium 210 in a manner of being plated or attached. For example, the waveguide medium 210 can be divided into a plurality of columns with parallelogram cross sections, and the transreflective elements 221 are disposed between the columns, that is, the medium between the adjacent transreflective elements 221 can be the waveguide medium 210. For example, the waveguide medium 210 includes a plurality of waveguide sub-media arranged in the first direction and attached to each other, the transreflective elements 221 are clamped between the adjacent waveguide sub-media, each waveguide sub-medium is configured to cause the light rays to undergo total internal reflection, and the transreflective elements are configured to couple out part of the light rays from the optical waveguide element by reflecting to destroy the total reflection condition of the part of the light rays.

[0103] FIG. 1A For example, the embodiments of the present disclosure are described by taking the plurality of transreflective elements 221 in the array of transreflective elements 220 as being parallel to each other, and the light rays emitted from the array of transreflective elements are parallel light. However, the embodiments of the present disclosure are not limited thereto, and the plurality of transreflective elements in the array of transreflective elements can also be non-parallel, and by adjusting the included angle between the plurality of transreflective elements, the light rays emitted from the array of transreflective elements can be adjusted to be converging light or diverging light.

[0104] For example, as shown in FIG. 2B, the transreflective element 221 can be disposed in the waveguide medium 210 in a manner of being plated or attached. For example, the waveguide medium 210 can be divided into a plurality of columns with parallelogram cross sections, and the transreflective elements 221 are disposed between the columns, that is, the medium between the adjacent transreflective elements 221 can be the waveguide medium 210. For example, the waveguide medium 210 includes a plurality of waveguide sub-media arranged in the first direction and attached to each other, the transreflective elements 221 are clamped between the adjacent waveguide sub-media, each waveguide sub-medium is configured to cause the light rays to undergo total internal reflection, and the transreflective elements are configured to couple out part of the light rays from the optical waveguide element by reflecting to destroy the total reflection condition of the part of the light rays.

[0105] For example, as shown in FIG. 2B, the transreflective element 221 can be disposed in the waveguide medium 210 in a manner of being plated or attached. For example, the waveguide medium 210 can be divided into a plurality of columns with parallelogram cross sections, and the transreflective elements 221 are disposed between the columns, that is, the medium between the adjacent transreflective elements 221 can be the waveguide medium 210. For example, the waveguide medium 210 includes a plurality of waveguide sub-media arranged in the first direction and attached to each other, the transreflective elements 221 are clamped between the adjacent waveguide sub-media, each waveguide sub-medium is configured to cause the light rays to undergo total internal reflection, and the transreflective elements are configured to couple out part of the light rays from the optical waveguide element by reflecting to destroy the total reflection condition of the part of the light rays. FIG. 1A ​As shown, the angle between each transflective element 221 and the light emitting surface 211 is a first angle, and the sum of the first angle and the critical angle of total reflection at which the light is totally reflected on the light emitting surface 211 is in the range of 60° to 120°. For example, the sum of the first angle and the critical angle of total reflection is in the range of 70° to 120°. For example, the sum of the first angle and the critical angle of total reflection is in the range of 80° to 100°. For example, the sum of the first angle and the critical angle of total reflection is in the range of 85° to 95°. In the embodiment of the present disclosure, by setting the first angle between the transflective element and the light emitting surface and the sum of the critical angle of total reflection at which the light is totally reflected on the light emitting surface, for the same light path, the light can be reflected only once in each transflective element, such as avoiding the transmission and reflection of light parallel or nearly parallel to the transflective element on it, thereby improving the uniformity of the light and reducing or avoiding the generation of stray light.

[0106] For example, each transflective element 221 forms a first angle with the first major surface 211, and a second angle forms a second angle between a light ray that propagates through total internal reflection in the waveguide medium 210 and the first major surface 211 and the second major surface 212. The difference between the first angle and the second angle is no greater than 10 degrees. For example, the difference between the first angle and the second angle is no greater than 5 degrees. For example, the first angle and the second angle are equal, meaning that the light ray that propagates through total internal reflection in the waveguide medium 210 is parallel to the transflective element 221. For the same light path, the light ray is only reflected once in each transflective element. This prevents light ray parallel to the transflective element from being transmitted and reflected therefrom, thereby improving light uniformity and reducing or preventing the generation of stray light.

[0107] For example, the first angle and the second angle may both be acute angles.

[0108] For example, FIG. 1B It is a schematic diagram of the partial structure of another display device. FIG. 1B and FIG. 1A The difference in the illustrated example is that a reflective device 600 is provided on the side of the optical waveguide element 200 away from the display panel 10. In this case, the angle between the transflective element 221 and the light beam transmitted by total internal reflection is not restricted and can be non-parallel, for example, greater than 10 degrees. In this case, by providing a reflective device on the side of the optical waveguide element away from the display panel, stray light that has escaped can be reflected back, thereby improving the uniformity of the light emitted from the optical waveguide element. For example, the reflective device can be a reflective layer or other reflective structure.

[0109] For example, FIG. 1A to FIG. 3As shown, the embodiments of the present disclosure schematically show that the orthographic projections of the adjacent transreflective elements 221 on the main surface are in contact with each other, which can avoid the dark area without light between two transreflective elements. However, the embodiments of the present disclosure are not limited thereto. The orthographic projections of the adjacent transreflective elements on the main surface can be partially overlapped, which can avoid the weakening of light at the edge of the transreflective element, and the overlapping of the transreflective elements can make the light more uniform.

[0110] For example, as shown in FIG. 1, the light source part 100 is arranged on the waveguide medium 210, and the light source part 100 is arranged on the main surface of the waveguide medium 210. FIG. 1A to FIG. 3 As shown, along the direction of the light propagating by total reflection in the waveguide medium 210, the plurality of transreflective elements 221 are uniformly arranged and the reflectivity gradually increases. For example, the reflectivity of the transreflective element 221 closer to the light source part 100 is smaller. For example, the reflectivity of the transreflective elements arranged in sequence along the extension direction of the light-out surface in the transreflective element array gradually increases or gradually increases in a region in the direction of the light propagating. For example, the arrangement density of the transreflective elements arranged in sequence along the extension direction of the light-out surface in the transreflective element array gradually increases or gradually increases in a region. For example, the gradual increase in a region can be two or more regions, and the reflectivity of the transreflective elements in different regions is different and gradually increases.

[0111] The above-mentioned uniform arrangement can refer to the arrangement in which the adjacent transreflective elements are arranged in contact with each other in orthographic projection, or the arrangement in which the adjacent transreflective elements are arranged to partially overlap in orthographic projection. Since the light gradually reflects out of the waveguide medium during the propagation process, the light intensity gradually attenuates, and therefore, by arranging the transreflective properties of the transreflective elements to be different, for example, the reflectivity of the transreflective elements gradually increases along the path of the light propagating by total reflection, the light intensity reflected by each transreflective element can be more uniform, and the light-out of each part of the waveguide medium 210 is more uniform.

[0112] For example, along the direction of the light propagating by total reflection in the waveguide medium, the arrangement density of the plurality of transreflective elements gradually increases. For example, the arrangement density of the transreflective elements closer to the light source part is smaller. For example, the position with small arrangement density can be that the adjacent transreflective elements are arranged in contact with each other in orthographic projection, and the position with large arrangement density can be that the adjacent transreflective elements are arranged to partially overlap in orthographic projection. For example, the position with small arrangement density can be that the adjacent transreflective elements are arranged to partially overlap in orthographic projection, and the overlapping part is small, and the position with large arrangement density can be that the adjacent transreflective elements are arranged to partially overlap in orthographic projection, and the overlapping part is large. The embodiments of the present disclosure can also make the intensity of the light reflected by each transreflective element uniform by adjusting the arrangement density of the transreflective elements while arranging the transreflective properties of the transreflective elements to be the same or almost the same.

[0113] For example, as shown in FIG. 1, the light source part 100 is arranged on the waveguide medium 210, and the light source part 100 is arranged on the main surface of the waveguide medium 210. FIG. 5 For example, as shown in FIG. 1, the light source part 100 is arranged on the waveguide medium 210, and the light source part 100 is arranged on the main surface of the waveguide medium 210. FIG. 1A Another schematic diagram of the planar structure of the backlight source according to the example shown in FIG. 1. FIG. 5 The backlight source shown in FIG. 1 and the backlight source shown in FIG. 2 are different in the arrangement of the transreflective elements. FIG. 3The backlights shown differ in that the reflectivity of the transflective elements in the transflective element array varies. FIG. 5 In the illustrated example, the transflective element array 220 includes at least two regions, such as region 01 and region 02. The average reflectivity of the transflective elements 221 in region 01 of the at least two regions is greater than the average reflectivity of the transflective elements 221 in the other regions (e.g., region 02). The greater average reflectivity of the transflective elements in region 01 than in the other regions can result in greater light intensity in region 01 than in the other regions. Of course, embodiments of the present disclosure are not limited to adjusting the intensity of light emitted from a region by adjusting the average reflectivity of the transflective elements within the region; other methods can also be used to adjust the intensity of light emitted from a region.

[0114] For example, region 01 may include at least one transflective element 221, while other regions 02 may include multiple transflective elements 221. The average reflectivity of the multiple transflective elements 221 in other regions is relatively low, resulting in uneven brightness of the light emitted by the optical waveguide element. This optical waveguide element is suitable for applications with uneven displays, such as billboards and displays that display content in a specific area. For example, region 01 may be located in the middle area, and other regions 02 may surround region 01. The disclosed embodiments are not limited to this. For example, the reflectivity of the multiple transflective elements 221 included in region 01 may gradually increase, while the reflectivity of the multiple transflective elements 221 in other regions is the same, resulting in uneven brightness of the light emitted by the optical waveguide element.

[0115] For example, the transflective element 221 can transmit and reflect light without wavelength selectivity or polarization selectivity. For example, an inorganic dielectric film layer can be used, such as a thin film formed by stacking one or more layers of metal oxide / metal nitride films, each layer having a thickness of approximately 10nm-1000nm. By changing the film material and / or the film stacking method, the overall transmission and reflection properties of the inorganic dielectric film layer can be controlled. As a result, the wavelength and polarization properties of light incident on the transflective element 221 remain virtually unchanged after transmission and reflection by the transflective element 221.

[0116] For example, at least one transflective element 221 in the transflective element array 220 includes a selective transmission film, and the light entering the optical waveguide element 200 includes a first polarized light and a second polarized light. The selective transmission film is configured to have a reflectivity for the first polarized light greater than a reflectivity for the second polarized light, and a transmittance for the second polarized light greater than a transmittance for the first polarized light. Thus, the transflective element can gradually reflect the first polarized light out of the optical waveguide element.

[0117] The light entering the light waveguide element can be non-polarized light or directly polarized light of two polarization states. Here, "non-polarized light" refers to light emitted by the light source portion that can have multiple polarization characteristics at the same time but does not exhibit a unique polarization characteristic. For example, the light emitted by the light source portion can be considered to be composed of light of two mutually perpendicular polarization states, i.e., the non-polarized light emitted by the light source portion can be decomposed into light of two mutually perpendicular polarization states.

[0118] For example, the light-transmitting and light-reflecting film can be a brightness enhancement film (BEF) that has a high reflectivity for one polarization of light and a high transmissivity for another polarization of light (for example, the light-transmitting and light-reflecting film has a high reflectivity for S-polarized light and a high transmissivity for P-polarized light), and the light-transmitting and light-reflecting element can use the selectivity of the polarized light-transmitting and light-reflecting film to cause the light to be gradually reflected out of the light waveguide element.

[0119] For example, as shown in FIG. 2A, the light emitted from the light-transmitting and light-reflecting element array 220 can be perpendicular to the major surface of the waveguide medium 210 when the light emitted from the light-transmitting and light-reflecting element array 220 does not satisfy the total reflection condition. FIG. 1A

[0120] An example in which the light emitted from the light-transmitting and light-reflecting element array is not perpendicular to the major surface of the waveguide medium. As shown in FIG. 2B, the direction of the light emitted from the light-transmitting and light-reflecting element array can be perpendicular to the major surface of the waveguide medium 210 when the angle of the light incident on the light-transmitting and light-reflecting element changes. FIG. 6 FIG. 6 An example in which the light emitted from the light-transmitting and light-reflecting element array is not perpendicular to the major surface of the waveguide medium. As shown in FIG. 2B, the direction of the light emitted from the light-transmitting and light-reflecting element array can be perpendicular to the major surface of the waveguide medium 210 when the angle of the light incident on the light-transmitting and light-reflecting element changes.

[0121] In the embodiments of the present disclosure, the light emitted from the light-transmitting and light-reflecting element array can be perpendicular or not perpendicular to the major surface of the waveguide medium, and the directions of the light emitted from different light-transmitting and light-reflecting elements can be parallel or approximately parallel, thereby forming a collimated light beam. In the embodiments of the present disclosure, a light waveguide element with a small thickness is used to convert the light emitted by the light source into collimated surface light source light, thereby saving the thickness of the display device.

[0122] FIG. 7 A schematic diagram of a partial structure of a backlight according to another example of the embodiments of the present disclosure. FIG. 7 The example shown in FIG. 3A is different from the example shown in FIG. 2A in that the number of light source portions and the arrangement of the light-transmitting and light-reflecting elements are different, and the positional relationship between adjacent light-transmitting and light-reflecting elements can be the same as the example shown in FIG. 2A. FIG. 1A The example shown in FIG. 3B is different from the example shown in FIG. 2B in that the number of light source portions and the arrangement of the light-transmitting and light-reflecting elements are different, and the positional relationship between adjacent light-transmitting and light-reflecting elements can be the same as the example shown in FIG. 2B. FIG. 1A The example shown in FIG. 3B is different from the example shown in FIG. 2B in that the number of light source portions and the arrangement of the light-transmitting and light-reflecting elements are different, and the positional relationship between adjacent light-transmitting and light-reflecting elements can be the same as the example shown in FIG. 2B. FIG. 7 As shown in FIG. 4A, the light-transmitting and light-reflecting element array 220 includes a first light-transmitting and light-reflecting element group 2201 and a second light-transmitting and light-reflecting element group 2202 arranged along a first direction, and each light-transmitting and light-reflecting element group includes a plurality of light-transmitting and light-reflecting elements 221 arranged along the first direction, and the light-transmitting and light-reflecting elements 221 of different light-transmitting and light-reflecting element groups are not parallel. For example, FIG. 7 ​It is schematically shown that the multiple transflective elements included in each transflective element group are parallel to each other, and the transflective elements in different transflective element groups are not parallel.

[0123] For example, FIG. 7 As shown, the light source unit 100 includes a first light source unit 110 and a second light source unit 120. The first light source unit 110 and the second light source unit 120 are respectively located on either side of a transflective element array 220 in a first direction. A first transflective element group 2201 is configured to reflect light entering the optical waveguide element 200 from the first light source unit 110, and a second transflective element group 2202 is configured to reflect light entering the optical waveguide element 200 from the second light source unit 120. For example, the first transflective element group 2201 is configured to reflect only light entering from the first light source unit 110, and the second transflective element group 2202 is configured to reflect only light entering from the second light source unit 2202. By providing two light source units and two transflective element groups, the disclosed embodiments can improve the intensity of light emitted from the optical waveguide element.

[0124] For example, FIG. 7 As shown, one of the transflective elements 221 in the first transflective element group 2201 and the second transflective element group 2202 has an acute angle with the first direction (the direction indicated by the arrow X), while the other has an obtuse angle with the first direction. The first transflective element group can reflect only light entering from the first light source, while the second transflective element group can reflect only light entering from the second light source. For example, the transflective elements 221 in the first transflective element group 2201 and the transflective elements 221 in the second transflective element group 2202 have different tilt directions.

[0125] For example, the light source portion may also be located between the first transflective element group and the second transflective element group in the extending direction of the light emitting surface.

[0126] For example, a reflective device may also be provided in the backlight source. The reflective device is provided on the other side away from the light emitting surface of the optical waveguide element, and is used to reflect the light leaking from the optical waveguide element back to the optical waveguide element, so that as much light as possible is converted into collimated light and output, thereby improving light utilization.

[0127] For example, FIG. 8 Schematic diagram of the partial structure of a backlight source in another example according to an embodiment of the present disclosure. FIG. 8 The example shown is the same as FIG. 1A The difference between the examples shown is the number of light source parts and the emission direction of the light reflected by the transflective element to the light source parts. FIG. 8As shown, the light source part 100 includes a first light source part 110 and a second light source part 120, and the first light source part 110 and the second light source part 120 are respectively located on both sides of the array of total internal reflection elements 220 in the first direction. The two side surfaces of each total internal reflection element 221 can reflect the light rays entering from the first light source part 110 or the second light source part 120, so that both side main surfaces of the light waveguide element are light exit surfaces.

[0128] For example, the reflectivity of the total internal reflection elements located at the middle position and / or near the middle position is greater than the reflectivity of the total internal reflection elements located at the two side positions, so that the light rays exiting from the light waveguide element have better uniformity. The backlight in the present example can be applied to scenarios requiring light to exit from both sides, such as billboards and the like.

[0129] For example, FIG. 9 A schematic view of a partial structure of a backlight according to another example of an embodiment of the present disclosure. As shown, FIG. 9 As shown, the backlight further includes a light splitting element 300 located between the light source part 100 and the light waveguide element 200, and the light splitting element 300 is configured to split the light rays emitted by the light source part 100 towards the light waveguide element 200 into multiple sub-beams. For example, the light splitting element 300 can split the light rays emitted by the light source part 100 towards the light waveguide element 200 into two sub-beams or three sub-beams, and the present disclosure is not limited thereto, but can also split into more sub-beams. For example, the light splitting element 300 can be a prism.

[0130] For example, as shown, FIG. 9 As shown, the light waveguide element 200 includes multiple sub-light waveguide elements 201, and the multiple sub-beams are configured to enter the multiple sub-light waveguide elements 201, and are reflected out of the light waveguide element 200 by the array of total internal reflection elements 221 located in each sub-light waveguide element 201. For example, the array of total internal reflection elements includes multiple sub-arrays of total internal reflection elements respectively located in the multiple sub-light waveguide elements. For example, the multiple sub-arrays of total internal reflection elements correspond one-to-one to the multiple sub-light waveguide elements.

[0131] For example, the number of the multiple sub-light waveguide elements 201 can be the same as the number of the multiple sub-beams, and at this time, the multiple sub-beams are configured to enter the corresponding sub-light waveguide elements one-to-one. The present disclosure is not limited thereto, and the number of the multiple sub-light waveguide elements can also be less than the number of the multiple sub-beams, and at this time, at least two sub-beams enter the same sub-light waveguide element.

[0132] For example, the thickness of the multiple sub-light waveguide elements 201 is less than, for example, FIG. 1AThe thickness of the light waveguide element in the embodiment shown; the light originally transmitted in one light waveguide element is split into multiple thinner waveguide elements after the light is split, and the light is transmitted in the waveguide element with smaller thickness. The number of total reflections increases, which can make the light distribution more uniform. For example, the uniformity in this embodiment can be the uniformity of light brightness. Generally, the light emitted by a light source (such as a point light source) is brighter in the middle and darker at the edges. After the light emitted by the light source is output through the light waveguide element, the collimated light coupled out is also brighter in the middle and darker at the edges. It is relatively difficult to adjust the brightness of the collimated light. Therefore, before the light emitted by the light source enters the light waveguide element or before the light is coupled out of the light waveguide element, the uniformity of the light is improved, and a surface light source light with uniform brightness can be obtained. For example, increasing the number of total reflections of the light can improve the uniformity of brightness, and therefore thinner light waveguide elements can be provided to increase the number of total reflections of the light.

[0133] In the embodiments of the present disclosure, by splitting the light of the light source part into multiple sub-beams and setting multiple sub-light waveguide elements to couple out the multiple sub-beams entering the sub-light waveguide elements, the uniformity of the light output by the backlight source can be further improved.

[0134] For example, the multiple sub-light waveguide elements can be independent structures or can be integrated on the same substrate.

[0135] For example, each sub-light waveguide element includes a waveguide medium, and the refractive indexes of the waveguide media in different sub-light waveguide elements can be the same or different, which is not limited in the embodiments of the present disclosure.

[0136] For example, the number and arrangement of the transreflective elements included in the transreflective element array in each sub-light waveguide element can be the same or different, which is not limited in the embodiments of the present disclosure.

[0137] For example, each sub-light waveguide element can include a light coupling-in part or can not include a light coupling-in part. For example, when each sub-light waveguide element includes a light coupling-in part, the light coupling-in parts of different sub-light waveguide elements can be the same, for example, both adopt a geometric method (for example, a non-grating coupling-in method such as a prism coupling-in or a reflection structure coupling-in), or can be different, which is not limited in the embodiments of the present disclosure.

[0138] For example, as shown in FIG. 6, the light waveguide element 600 includes a light coupling-in part 610 and a light coupling-out part 620. The light coupling-in part 610 is configured to couple the light emitted by the light source into the light waveguide element 600. The light coupling-out part 620 is configured to couple the light in the light waveguide element 600 out of the light waveguide element 600. FIG. 9As shown, the optical waveguide element 200 includes a plurality of sub-optical waveguide elements 201, and the transflective element array 210 includes a plurality of sub-transflective element arrays respectively located in the plurality of sub-optical waveguide elements 201; the backlight source further includes a spectroscopic element 300, which is configured to split the light emitted by the light source unit 100 toward the optical waveguide element 200 into a plurality of sub-beams and allow the plurality of sub-beams to enter the plurality of sub-optical waveguide elements 201 respectively, and each sub-beam entering each sub-optical waveguide element 201 is reflected by the sub-transflective element array located in each sub-optical waveguide element 201 out of the light exit surface of the optical waveguide element 200.

[0139] For example, the light emitted by the light source unit 100 and directed toward the optical waveguide element 200 includes a first characteristic light and a second characteristic light having different characteristics. The spectroscopic element 300 is configured to perform spectroscopic processing on the light emitted by the light source unit 100 and directed toward the optical waveguide element 200, so that the first characteristic light obtained by the spectroscopic processing is incident on the first sub-optical waveguide element 2011, and the second characteristic light obtained by the spectroscopic processing is incident on the second sub-optical waveguide element 2012.

[0140] For example, the first characteristic light and the second characteristic light are first polarized light and second polarized light with different polarization states, respectively; or the first characteristic light and the second characteristic light are first color light and second color light with different colors, respectively.

[0141] For example, the beam splitter element includes a polarization beam splitter element configured to reflect one of the first polarization light and the second polarization light and transmit the other of the first polarization light and the second polarization light, and further includes a reflective element configured to reflect one of the first polarization light and the second polarization light.

[0142] For example, FIG. 9 As shown, the plurality of sub-beams include a first polarized beam 1001 and a second polarized beam 1002 having different polarization directions. The beam splitter 300 includes a polarization splitter 310. The polarization splitter 310 is configured to perform polarization splitting on the light emitted by the light source 100 and directed toward the optical waveguide element 200, so that the plurality of sub-beams include the first polarized beam 1001 and the second polarized beam 1002 having different polarization states. The second polarized beam 1002 is incident on the second sub-optical waveguide element 2012, and the first polarized beam 1001 is incident on the first sub-optical waveguide element 2011. The polarization splitter transmits the second polarized beam and reflects the first polarized beam, but this is not limited to reflecting only the second polarized beam and transmitting the first polarized beam. For example, the polarization splitter may have a high transmittance for the second polarized beam and a high reflectance for the first polarized beam. In the disclosed embodiments, the first polarized beam and the second polarized beam may be interchangeable.

[0143] For example, FIG. 9As shown, the transflective element of the first sub-optical waveguide element 2011 is configured so that the reflectivity of the first polarized light is greater than the reflectivity of the second polarized light, and the transflective element of the second sub-optical waveguide element 2012 is configured so that the reflectivity of the second polarized light is greater than the reflectivity of the first polarized light, which can increase the intensity of the light emitted by the backlight source and improve the utilization rate of the light.

[0144] Of course, the embodiments of the present disclosure are not limited thereto, and the transflective element in each sub-optical waveguide element may also have no polarization selection characteristic.

[0145] For example, FIG. 9 As shown, the beam splitting element 300 further includes a reflective element 320, which is configured to reflect the first polarized light beam 1001 into the first sub-optical waveguide element 2011. The disclosed embodiments are not limited thereto; the reflective element may also be configured to reflect the second polarized light beam into the second sub-optical waveguide element. For example, the reflective element is configured to transmit the split first polarized light beam to the first sub-optical waveguide element. The reflective element may be replaced by other elements having similar functions.

[0146] For example, after the non-polarized light emitted by the light source unit 100 passes through the polarization splitting element 310 with the polarization splitting function, the transmitted light includes P-polarized light (for example, the second polarized light) and the reflected light includes S-polarized light (for example, the first polarized light); or the transmitted light includes S-polarized light (for example, the second polarized light) and the reflected light includes P-polarized light (for example, the first polarized light). The embodiments of the present disclosure are not limited to this.

[0147] For example, the polarization splitter element 310 can have the function of transmitting light with one characteristic and reflecting light with another characteristic. For example, the polarization splitter element 310 can have the characteristic of transmitting light with one polarization state and reflecting light with another polarization state. The polarization splitter element 310 can use the above-mentioned transmission and reflection characteristics to achieve beam splitting.

[0148] For example, the polarization beam splitting element 310 may be a transflective film that transmits a portion of the light and reflects another portion of the light to achieve beam splitting. For example, the transflective film may transmit the second polarized light in the light emitted by the light source unit 100 and reflect the first polarized light in the light emitted by the light source unit 100.

[0149] For example, the transflective film can be an optical film with polarization transflective function, specifically an optical film that can split non-polarized light into two mutually perpendicular polarized lights through transmission and reflection; the above-mentioned optical film can be composed of multiple layers of film layers with different refractive indices combined in a certain stacking order, and the thickness of each film layer is approximately between 10 and 1000 nm; the material of the film layer can be an inorganic dielectric material, such as metal oxides and metal nitrides; it can also be a polymer material, such as polypropylene, polyvinyl chloride or polyethylene.

[0150] For example, the transmitted P-polarized light enters the second sub light waveguide element 2012 through the second light incoupling part 232 in the second sub light waveguide element 2012, and the reflected S-polarized light enters the first sub light waveguide element 2011 through the reflection of the reflection element 320 to enter the first sub light waveguide element 2011. The S-polarized light and the P-polarized light pass through the array of transreflective elements in the respective waveguide elements to be output in a collimated light ray state, which can achieve the effect of converting a general light source into a uniform surface light source.

[0151] For example, as shown in FIG. 13, the plurality of sub light waveguide elements are arranged to overlap in a direction perpendicular to the display surface of the display panel, thereby improving the brightness of the backlight and the uniformity of the light rays. The above-mentioned overlapping arrangement includes complete overlapping arrangement and partial overlapping arrangement, that is, the orthogonal projection of the plurality of sub light waveguide elements on the plane parallel to the light exit surface of the light waveguide element can be completely overlapped or partially overlapped, and the embodiments of the present disclosure do not limit this. FIG. 9 The first sub light waveguide element and the second sub light waveguide element are arranged to completely overlap. FIG. 9 For example, as shown in FIG. 13, the plurality of sub light waveguide elements are arranged to overlap in a direction perpendicular to the display surface of the display panel, thereby improving the brightness of the backlight and the uniformity of the light rays. The above-mentioned overlapping arrangement includes complete overlapping arrangement and partial overlapping arrangement, that is, the orthogonal projection of the plurality of sub light waveguide elements on the plane parallel to the light exit surface of the light waveguide element can be completely overlapped or partially overlapped, and the embodiments of the present disclosure do not limit this.

[0152] The first sub light waveguide element and the second sub light waveguide element are arranged to completely overlap. FIG. 9 For example, as shown in FIG. 13, the first sub light waveguide element 2011 and the second sub light waveguide element 2012 overlap in a direction perpendicular to the display surface of the display panel, that is, the first sub light waveguide element 2011 and the second sub light waveguide element 2012 overlap in the Y direction, and the light rays emitted from the second sub light waveguide element 2012 are emitted to the display panel after passing through the first sub light waveguide element 2011. For example, as shown in FIG. 13, the light rays emitted from the second sub light waveguide element 2012 can pass through the array of transreflective elements in the first sub light waveguide element 2011, or can not pass through the array of transreflective elements in the first sub light waveguide element 2011, and the embodiments of the present disclosure do not limit this. FIG. 9 The first sub light waveguide element and the second sub light waveguide element are arranged to completely overlap. The first sub light waveguide element and the second sub light waveguide element are arranged to completely overlap. For example, when the light rays emitted from the second sub light waveguide element pass through the array of transreflective elements in the first sub light waveguide element, the array of transreflective elements in the first sub light waveguide element has a high transmittance to the transmitted light rays.

[0153] The first sub light waveguide element and the second sub light waveguide element are arranged to completely overlap. For example, as shown in FIG. 13, the first polarized light beam 1001 transmitted to the transreflective element of the first sub light waveguide element 2011 has a third included angle with the transreflective element, the second polarized light beam 1002 transmitted to the transreflective element of the second sub light waveguide element 2012 has a fourth included angle with the transreflective element, and the difference between the third included angle and the fourth included angle is not greater than 5 degrees. The above-mentioned third included angle and the fourth included angle can both refer to the included angle of the light rays incident to the surface of the transreflective element and transmitted. The first sub light waveguide element and the second sub light waveguide element are arranged to completely overlap.

[0154] The first sub light waveguide element and the second sub light waveguide element are arranged to completely overlap. For example, as shown in FIG. 13, the first polarized light beam 1001 transmitted to the transreflective element of the first sub light waveguide element 2011 has a third included angle with the transreflective element, the second polarized light beam 1002 transmitted to the transreflective element of the second sub light waveguide element 2012 has a fourth included angle with the transreflective element, and the difference between the third included angle and the fourth included angle is not greater than 5 degrees. The above-mentioned third included angle and the fourth included angle can both refer to the included angle of the light rays incident to the surface of the transreflective element and transmitted. FIG. 9 The first sub light waveguide element and the second sub light waveguide element are arranged to completely overlap. The first sub light waveguide element and the second sub light waveguide element are arranged to completely overlap.

[0155] For example, when the third included angle and the fourth included angle are equal, the angle of the polarized light entering the sub-light waveguide element can be adjusted according to the tilt angle of the transmissive-refl ective element in each sub-light waveguide element. For example, setting the included angles between different sub-light waveguide elements and the corresponding polarized light to be the same can facilitate the manufacture of the sub-light waveguide elements and the adjustment of the incident light angle.

[0156] For example, as shown in FIG. 10A, the total reflection propagation direction of the first polarized light beam 1001 entering the first sub-light waveguide element 2011 is the same as the total reflection propagation direction of the second polarized light beam 1002 entering the second sub-light waveguide element 2012, the included angle between the transmissive-refl ective element in the first sub-light waveguide element 2011 and the transmissive-refl ective element in the second sub-light waveguide element 2012 is not greater than 5 degrees, for example, the transmissive-refl ective elements in the two sub-light waveguide elements are parallel, to facilitate the manufacture of the light waveguide element. FIG. 9 For example, as shown in FIG. 10B, the included angles between the transmissive-refl ective element in the first sub-light waveguide element 2011 and the transmissive-refl ective element in the second sub-light waveguide element 2012 and the first direction are both acute angles, or both obtuse angles. For example, the tilt directions of the transmissive-refl ective element in the first sub-light waveguide element 2011 and the transmissive-refl ective element in the second sub-light waveguide element 2012 are the same. Here, the tilt direction can refer to the tilt direction of the transmissive-refl ective element relative to the light-out surface. However, it is not limited thereto, and the tilt direction here can also refer to the tilt to the left or right relative to the Y direction.

[0157] FIG. 9 For example, as shown in FIG. 10C, the included angles between the transmissive-refl ective element in the first sub-light waveguide element 2011 and the transmissive-refl ective element in the second sub-light waveguide element 2012 and the first direction are both acute angles, or both obtuse angles. For example, the tilt directions of the transmissive-refl ective element in the first sub-light waveguide element 2011 and the transmissive-refl ective element in the second sub-light waveguide element 2012 are the same. Here, the tilt direction can refer to the tilt direction of the transmissive-refl ective element relative to the light-out surface. However, it is not limited thereto, and the tilt direction here can also refer to the tilt to the left or right relative to the Y direction.

[0158] For example, as shown in FIG. 10D, the direction indicated by the arrow in the X direction is the first direction (for example, when the above-mentioned included angle with the direction is involved, the first direction can be regarded as a vector) and the total reflection propagation direction of the first polarized light beam 1001 entering the first sub-light waveguide element 2011 is the same as the total reflection propagation direction of the second polarized light beam 1002 entering the second sub-light waveguide element 2012, when the total reflection propagation direction of each polarized light is the same as the first direction, the included angle between each transmissive-refl ective element and the first direction is an acute angle; when the total reflection propagation direction of each polarized light is opposite to the first direction, the included angle between each transmissive-refl ective element and the first direction is an obtuse angle. FIG. 9 For example, as shown in FIG. 11A, the included angle between the transmissive-refl ective element in the first sub-light waveguide element 2011 and the transmissive-refl ective element in the second sub-light waveguide element 2012 and the first direction is an acute angle, and the total reflection propagation direction of the first polarized light beam 1001 entering the first sub-light waveguide element 2011 is opposite to the total reflection propagation direction of the second polarized light beam 1002 entering the second sub-light waveguide element 2012.

[0159] FIG. 10 For example, as shown in FIG. 11B, the included angle between the transmissive-refl ective element in the first sub-light waveguide element 2011 and the transmissive-refl ective element in the second sub-light waveguide element 2012 and the first direction is an obtuse angle, and the total reflection propagation direction of the first polarized light beam 1001 entering the first sub-light waveguide element 2011 is opposite to the total reflection propagation direction of the second polarized light beam 1002 entering the second sub-light waveguide element 2012. FIG. 10 FIG. 9 For example, as shown in FIG. 12A, the included angle between the transmissive-refl ective element in the first sub-light waveguide element 2011 and the transmissive-refl ective element in the second sub-light waveguide element 2012 and the first direction is an acute angle, and the total reflection propagation direction of the first polarized light beam 1001 entering the first sub-light waveguide element 2011 is opposite to the total reflection propagation direction of the second polarized light beam 1002 entering the second sub-light waveguide element 2012. FIG. 10 ​​​As shown, the plurality of sub-light waveguide elements are arranged along the first direction. For example, the plurality of sub-light waveguide elements do not overlap in the direction perpendicular to the display surface of the display panel, which can reduce the thickness of the backlight, and can also reduce the degree of weakening of the light intensity at the edge of the light waveguide element by setting the length of each sub-light waveguide element to be small. For example, the plurality of sub-light waveguide elements do not overlap in the direction perpendicular to the display surface of the display panel, which can be just connected, or there can be a certain distance, such as FIG. 10 As shown.

[0160] For example, the plurality of sub-light waveguide elements can include first sub-light waveguide elements 2011 and second sub-light waveguide elements 2012 arranged along the first direction. The second polarized light beam 1002 transmitted by the polarization splitting element 310 passes through the second light incoupling part 232 in the second sub-light waveguide element 2012 and enters the second sub-light waveguide element 2012, and the reflected first polarized light beam 1001 passes through the first light incoupling part 231 in the first sub-light waveguide element 2011 without passing through the reflecting element and enters the first sub-light waveguide element 2011. The first polarized light beam 1001 and the second polarized light beam 1002 pass through the array of transreflective elements in the respective sub-waveguide elements and are output in a collimated light ray state, which can achieve the effect of converting a general light source into a uniform surface light source.

[0161] For example, the total reflection propagation direction of the light rays in the first sub-light waveguide element 2011 is opposite to the total reflection propagation direction of the light rays in the second sub-light waveguide element 2012, and the transreflective elements in the first sub-light waveguide element 2011 and the transreflective elements in the second sub-light waveguide element 2012 are not parallel, for example, one of them has an acute angle with the first direction, and the other has an obtuse angle with the first direction, to achieve the coupling-out of the light rays by the transreflective elements. For example, the inclination directions of the transreflective elements in the first sub-light waveguide element 2011 and the transreflective elements in the second sub-light waveguide element 2012 are different.

[0162] For example, FIG. 11 A partial structure schematic diagram of a backlight according to another example of an embodiment of the present disclosure is shown. As shown, FIG. 11 The light splitting element 300 is configured to split the light rays emitted by the light source part 100 into a plurality of beams of light rays with different wavelengths. For example, the light splitting element 300 can include a light splitting prism, a light splitting grating, or other elements that can separate light rays of different wavelengths.

[0163] For example, as FIG. 11As shown, the plurality of sub-light beams includes first color light 1003 and second color light 1004 of different wavelengths, the plurality of sub-light waveguide elements 201 includes first sub-light waveguide element 2011 and second sub-light waveguide element 2012, the first color light 1003 is configured to enter the first sub-light waveguide element 2011, and is reflected out of the first sub-light waveguide element 2011 by the array of transreflective elements located in the first sub-light waveguide element 2011, and the second color light 1004 is configured to enter the second sub-light waveguide element 2012, and is reflected out of the second sub-light waveguide element 2012 by the array of transreflective elements located in the second sub-light waveguide element 2012.

[0164] The embodiment of the present disclosure is advantageous for the total reflection propagation regulation of light rays of different colors by entering the light rays of different colors into different sub-light waveguide elements, so as to improve the utilization rate of light rays.

[0165] For example, the transreflective elements of the first sub-light waveguide element 2011 are configured to have a reflectivity to the first color light 1003 greater than a reflectivity to the second color light 1004, and the transreflective elements of the second sub-light waveguide element 2012 are configured to have a reflectivity to the second color light 1004 greater than a reflectivity to the first color light 1003. The embodiment of the present disclosure can improve the utilization rate of light rays entering the corresponding sub-light waveguide elements by regulating the reflectivity and transmissivity of the transreflective elements in different sub-light waveguide elements.

[0166] For example, the first color light 1003 can be red light or green light, and the second color light 1004 can be blue light. The embodiment of the present disclosure is not limited thereto, and the first color light and the second color light can be interchanged.

[0167] For example, FIG. 12 FIG. 2 is a schematic diagram of a partial structure of a backlight according to another example of the embodiment of the present disclosure. As shown in FIG. 2, the backlight includes a plurality of sub-light beams 1001, a plurality of sub-light waveguide elements 201, and a plurality of light sources 200. FIG. 12 As shown, the plurality of sub-light beams further includes third color light 1005, and the third color light 1005 is configured to enter one of the first sub-light waveguide element 2011 and the second sub-light waveguide element 2012. For example, as shown in FIG. 2, the first color light 1003 and the third color light 1005 enter the first sub-light waveguide element 2011, and the second color light 1004 enters the second sub-light waveguide element 2012. The embodiment of the present disclosure is not limited thereto, and the third color light can also enter the same sub-light waveguide element as the second color light. FIG. 12 As shown, the first color light 1003 and the third color light 1005 enter the first sub-light waveguide element 2011, and the second color light 1004 enters the second sub-light waveguide element 2012. The embodiment of the present disclosure is not limited thereto, and the third color light can also enter the same sub-light waveguide element as the second color light.

[0168] In the embodiment of the present disclosure, by entering two different color light rays into the same sub-light waveguide element, the manufacturing cost of the light waveguide element can be reduced, and the thickness of the backlight can also be reduced.

[0169] For example, the first color light 1003 and the third color light 1005 can be red light and green light respectively, and the second color light 1004 can be blue light. The embodiments of the present disclosure are not limited thereto, and the first color light and the third color light can also be green light and blue light respectively, and the second color light can be red light.

[0170] In the embodiments of the present disclosure, the two color lights with similar wavelengths are entered into the same sub-light waveguide element, which can facilitate the adjustment of the array of transmissive and reflective elements in the sub-light waveguide element, and can also reduce the cost.

[0171] For example, FIG. 13 A partial structure schematic diagram of a backlight according to another example of the embodiments of the present disclosure is shown. FIG. 13 The example shown is different from FIG. 12 The difference between the example shown and the example shown in FIG. 1 is that the multiple beams of different color lights are configured to enter the multiple sub-light waveguide elements one by one. As shown in FIG. 2, FIG. 13 As shown, the multiple sub-light beams further include the third color light 1005, and the multiple sub-light waveguide elements 201 further include a third sub-light waveguide element 2013, the third color light 1005 is configured to enter the third sub-light waveguide element 2013, and is reflected out of the third sub-light waveguide element 2013 by the array of transmissive and reflective elements located in the third sub-light waveguide element 2013. The embodiments of the present disclosure can further improve the utilization rate of light by entering different color lights into different sub-light waveguide elements one by one.

[0172] For example, as shown in FIG. 3, FIG. 13 As shown, the transmissive and reflective elements of the first sub-light waveguide element 2011 are configured to have a reflectivity to the first color light 1003 greater than the reflectivity to the second color light 1004 and the third color light 1005, the transmissive and reflective elements of the second sub-light waveguide element 2012 are configured to have a reflectivity to the second color light 1004 greater than the reflectivity to the first color light 1003 and the third color light 1005, and the transmissive and reflective elements of the third sub-light waveguide element 2013 are configured to have a reflectivity to the third color light 1005 greater than the reflectivity to the first color light 1003 and the second color light 1004. The embodiments of the present disclosure can improve the utilization rate of light incident into the corresponding sub-light waveguide element by regulating the reflectivity and transmissivity of the transmissive and reflective elements in the different sub-light waveguide elements.

[0173] For example, as shown in FIG. 4, FIG. 13As shown, the refractive index of the waveguide medium of the first sub light waveguide element 2011, the refractive index of the waveguide medium of the second sub light waveguide element 2012, and the refractive index of the waveguide medium of the third sub light waveguide element 2013 can be different, and each is set to adapt to the refractive index of the light entering the corresponding sub light waveguide element. For example, the first color light 1003, the second color light 1004, and the third color light 1005 are blue light, red light, and green light, respectively. If the three kinds of light are coupled into the same light waveguide element, the light of different wavelengths propagates in the same medium, and the refractive index of the medium for various light is different, so the total reflection angle of the three kinds of light is different (for example, the total reflection critical angle of red light is greater than that of blue light), and the angle of the transmissive and reflective element is also considered for the light propagating in three angles, so the efficiency is low; if the total reflection angles of the three kinds of light are close, the medium also needs to be adjusted to have different refractive indexes. Therefore, the various light is separated, and each sub light waveguide element can select a medium and a corresponding transmissive and reflective element that can propagate the corresponding light as much as possible to meet the total reflection condition, so as to improve the utilization rate of light.

[0174] For example, the embodiments of the present disclosure are not limited to the multiple sub light beams being sub light beams with different polarization directions or wavelengths, and each of the multiple sub light beams can also be a sub light beam with the same property, that is, the light splitting element is only configured to split the one light beam emitted by the light source part into multiple sub light beams with the same property, and the multiple sub light beams are configured to enter the multiple sub light waveguide elements one by one. Compared with the one light beam emitted by the light source part entering one light waveguide element, the embodiments of the present disclosure can improve the utilization rate of light and the uniformity of the coupled-out light by splitting the one light beam emitted by the light source part into multiple light beams and entering different sub light waveguide elements respectively. When each of the multiple sub light beams has the same property, the multiple sub light waveguide elements can overlap or not overlap in the direction perpendicular to the display surface of the display panel.

[0175] For example, the light waveguide element includes multiple sub light waveguide elements, and whether the multiple sub light waveguide elements are arranged in the direction parallel to the display surface of the display panel or in the direction perpendicular to the display surface of the display panel, in at least one of the multiple sub light waveguide elements, multiple transmissive and reflective elements are uniformly arranged and the reflectivity gradually increases along the direction in which the light propagates by total reflection in the waveguide medium.

[0176] For example, the light waveguide element includes multiple sub light waveguide elements, and whether the multiple sub light waveguide elements are arranged in the direction parallel to the display surface of the display panel or in the direction perpendicular to the display surface of the display panel, in at least one of the multiple sub light waveguide elements, the arrangement density of multiple transmissive and reflective elements gradually increases along the direction in which the light propagates by total reflection in the waveguide medium.

[0177] In the research, the inventors of the present application also found that: the liquid crystal layer of the liquid crystal display device is provided with two polarizers with different light transmission directions on both sides, one of which is arranged between the liquid crystal layer and the backlight source, only light with a specific polarization state can pass through the polarizer between the liquid crystal layer and the backlight source to enter the inside of the liquid crystal display panel and be used for imaging. For example, when the light emitted by the backlight source is non-polarized light, at most 50% of the light emitted by the backlight source can be used by the liquid crystal layer, and the remaining light will be wasted or absorbed by the liquid crystal layer to generate heat, causing the problem of low light utilization rate.

[0178] FIG. 14 A partial structure schematic diagram of a backlight source provided according to an example of another embodiment of the present disclosure is provided. The backlight source in the present embodiment can also be referred to as a light source device, which can be applied to a display device together with a display panel, or can be used alone, and the present embodiment does not limit this. For example, the light source device in the present embodiment can be arranged at the back side of a transmissive display panel, or can be arranged at the display side of a reflective display panel to provide light for the display panel. The light source device (for example, a backlight source) in the present embodiment can be applied to any display device that needs a light source.

[0179] As shown in FIG. 14 , the light source device includes a light source part 100, and the light emitted by the light source part 100 includes first polarized light 100-1 and second polarized light 100-2 with different polarization states. The light source part 100 is configured to make the light emitted by the light source part 100 reflectively propagate in the light waveguide element 200 after entering the light waveguide element 200. The light coupling-out part 240 is configured to couple out the light that reflectively propagates in the light waveguide element 200. The light coupling-out part 240 includes a first light coupling-out part 241 and a second light coupling-out part 242. The first light coupling-out part 241 is configured to couple out the first polarized light 100-1 that enters the light waveguide element 200. The light source device further includes a polarization conversion structure 400, which is configured to convert the second polarized light 100-2 that enters the light waveguide element 200 into the first polarized light 100-1. The second light coupling-out part 242 is configured to couple out the converted first polarized light 100-1 after the polarization conversion structure 400 converts the second polarized light 100-2 that enters the light waveguide element 200 into the first polarized light 100-1. Alternatively, the second light coupling-out part 242 is configured to couple out the second polarized light 100-2 that enters the light waveguide element 200 to the polarization conversion structure 400, so that the coupled-out second polarized light 100-2 is converted into the first polarized light 100-1 by the polarization conversion structure 400.

[0180] As shown in FIG. 14As shown, the backlight includes a light source unit 100 and an optical waveguide element 200. The light emitted by the light source unit 100 includes a first polarized light 100-1 and a second polarized light 100-2 having different polarization states. The optical waveguide element 200 includes a waveguide medium 210 and an optical coupling unit 240. The light emitted by the light source unit 100 is configured to enter the waveguide medium 210 and propagate through total reflection in the waveguide medium 210. The optical coupling unit 240 is configured to couple the light that has been totally reflected in the waveguide medium 210 to a predetermined area 40.

[0181] For example, FIG. 14 As shown, polarized lights of different polarization states emitted by the light source unit 100 can respectively obtain a first polarized beam 1001 and a second polarized beam 1002 after passing through the light splitting structure. The first polarized beam 1001 and the second polarized beam 1002 have different polarization states.

[0182] For example, the first optical coupling unit 241 is configured to couple the first polarized light beam 1001 entering the optical waveguide element 200 out to the predetermined region 40. FIG. 14 As shown, the backlight source further includes a polarization conversion structure 400, which is configured to convert the second polarized light beam 1002 after entering the optical waveguide element 200 into a first polarized light beam 1001'. The second light coupling unit 242 is configured to couple the converted first polarized light beam 1001' to the predetermined area 40, or to couple the second polarized light beam 1002 to the polarization conversion structure 400 to convert the second polarized light beam 1002 into the first polarized light beam 1001' before emitting the first polarized light beam to the predetermined area 40.

[0183] The polarization conversion structure provided in the backlight source can convert the non-polarized light emitted from the light source into polarized light with a specific polarization state. The polarized light can be utilized by the liquid crystal layer through the polarizer between the liquid crystal layer and the backlight source to improve the utilization rate of light.

[0184] For example, FIG. 14 In the example shown, the second polarized light beam 1002 coupled out from the second light coupling unit 242 is converted into a first polarized light beam 1001 ′ after passing through the polarization conversion structure 400 . The converted first polarized light beam 1001 ′ is emitted toward the predetermined area 40 together with the first polarized light beam 1001 coupled out from the first light coupling unit 241 .

[0185] For example, the predetermined area 40 may refer to a certain area between the backlight source and the display panel, but is not limited thereto. The predetermined area may be any area located on the light-emitting side of the backlight source.

[0186] For example, the light source unit 100 in this embodiment can be connected to FIG. 1A to FIG. 13 The light source unit 100 in the embodiment shown has the same features, which will not be described in detail here.FIG. 1A to FIG. 13 The waveguide medium 210 in the illustrated embodiment has the same features, which are not repeated here.

[0187] For example, the light coupling-in portion can be provided in the embodiment, and can also not be provided. For example, the light coupling-in portion provided in the embodiment can have the same or similar features as the light coupling-in portion provided in the first embodiment, which are not repeated here. FIG. 1A to FIG. 13 The light coupling-in portion provided in the illustrated embodiment has the same or similar features, which are not repeated here.

[0188] For example, the light emitted by the light source portion 100 can be unpolarized light, which includes first polarized light beams 1001 and second polarized light beams 1002 with different polarization directions. For example, the first polarized light beams 1001 and the second polarized light beams 1002 can be two linearly polarized lights with perpendicular polarization directions, such as S-polarized light and P-polarized light. The embodiments of the present disclosure are not limited to this, and the first polarized light and the second polarized light can also be two circularly polarized lights with opposite rotation directions or elliptically polarized light. For example, the embodiments of the present disclosure are not limited to the light emitted by the light source portion including only two polarization states, but can also include three or more polarization states.

[0189] For example, the first polarized light beams 1001 emitted from the first light coupling-out portion 241 do not change their characteristics in the process of being incident on the predetermined region 40. For example, the converted first polarized light beams 1001' have the same characteristics as the first polarized light beams 1001 in the light emitted by the light source portion 100, i.e., are polarized light with the same polarization state. For example, the second polarized light beams 1002 emitted from the second light coupling-out portion 242 change the polarization direction in the process of being incident on the predetermined region 40.

[0190] For example, the embodiments of the present disclosure are not limited to the light emitted by the light source portion propagating in the light waveguide element in a total reflection manner, and for example, the light emitted by the light source portion can also propagate in the transmissive and reflective element in a non-total reflection manner, such as linear propagation.

[0191] FIG. 15 A partial structure schematic diagram of a backlight source is provided according to an example of another embodiment of the present disclosure. As shown in the figure, FIG. 15 As shown, the backlight source further includes a light splitting element 300 configured to perform light splitting processing on the light emitted by the light source portion 100 and directed to the light waveguide element 200. For example, the light splitting element 300 can be located between the light source portion 100 and the light waveguide element 200, and is configured to split the light emitted by the light source portion 100 and directed to the light waveguide element 200 into first polarized light beams 1001 and second polarized light beams 1002.

[0192] For example, the light source part 100 emits unpolarized light, the light splitting element 300 includes a polarization splitting element 310 configured to reflect one of the first polarized light and the second polarized light, and transmit the other of the first polarized light and the second polarized light; the light splitting element 300 further includes a reflecting element 320 configured to reflect one of the first polarized light and the second polarized light.

[0193] For example, the polarization splitting element 310 is configured to split the unpolarized light emitted by the light source part 100 into a first polarized light beam 1001 and a second polarized light beam 1002 before the unpolarized light is incident on the light waveguide element 200.

[0194] For example, as shown in FIG. 2A, the light waveguide element 200 includes a first sub-element 2001 and a second sub-element 2002, and the first sub-element 2001 is provided with a first light out-coupling part 241. FIG. 15 For example, the first polarized light beam 1001 is configured to enter the first sub-element 2001 and is coupled out of the first light out-coupling part 241 to the predetermined region 40, i.e., the first polarized light beam 1001 output by the first light out-coupling part 241 is directly output, for example, collimated light.

[0195] For example, as shown in FIG. 2A, the light waveguide element 200 includes a first sub-element 2001 and a second sub-element 2002, and the first sub-element 2001 is provided with a first light out-coupling part 241. FIG. 15 For example, the second sub-element 2002 includes a second light out-coupling part 242, and the polarization conversion structure 400 is configured to convert the second polarized light coupled out of the second light out-coupling part 242 into the first polarized light.

[0196] For example, as shown in FIG. 2A, the light waveguide element 200 includes a first sub-element 2001 and a second sub-element 2002, and the first sub-element 2001 is provided with a first light out-coupling part 241. FIG. 15 For example, the second sub-element 2002 is provided with the second light out-coupling part 242, and the polarization conversion structure 400 is disposed on the light output side of the second light out-coupling part 242 to convert the second polarized light beam 1002 coupled out of the second light out-coupling part 242 into the first polarized light beam 1001'. FIG. 15 For example, as shown in FIG. 2A, the light waveguide element 200 includes a first sub-element 2001 and a second sub-element 2002, and the first sub-element 2001 is provided with a first light out-coupling part 241. FIG. 9 For example, as shown in FIG. 2A, the light waveguide element 200 includes a first sub-element 2001 and a second sub-element 2002, and the first sub-element 2001 is provided with a first light out-coupling part 241.

[0197] For example, FIG. 15The first sub-element and the second sub-element are schematically shown as separate structures, but are not limited thereto. The first sub-element and the second sub-element can also be an integrated structure. For example, the first sub-element and the second sub-element can be connected by a connecting portion on a side away from the light source portion. The embodiments of the present disclosure are not limited to this and can be set according to actual needs. The above-mentioned "the first sub-element and the second sub-element can also be an integrated structure" can mean that the first sub-element and the second sub-element are the same structure formed by the same material through a one-step process, or it can mean that the first sub-element and the second sub-element are connected together by a fixing method such as bonding.

[0198] For example, FIG. 15 As shown, the first sub-element 2001 includes a light-emitting surface 001, and the first sub-element 2001 and the second sub-element 2002 overlap in a direction perpendicular to the light-emitting surface 001 (i.e., the Y direction shown in the figure), and the polarization conversion structure 400 is located between the first sub-element 2001 and the second sub-element 2002. The above-mentioned overlap can include complete overlap and partial overlap, for example, the orthographic projections of the first sub-element and the second sub-element on a plane parallel to the light-emitting surface completely overlap or partially overlap. FIG. 15 It is schematically shown that the first sub-element and the second sub-element completely overlap in the Y direction.

[0199] For example, FIG. 15 As shown, when the first sub-element 2001 and the second sub-element 2002 overlap in the Y direction, the converted first polarized light beam 1001' passes through the first sub-element 2001 and then is emitted toward the predetermined area 40. For example, the converted first polarized light beam 1001' may or may not pass through the first light outcoupling portion 241, and this is not limited in the present embodiment.

[0200] In some embodiments of the present disclosure, the first sub-element and the second sub-element are overlapped to increase the brightness of the backlight source and improve the uniformity of the light.

[0201] For example, FIG. 15 As shown, the polarization beam splitter 310 is configured to transmit the second polarized beam 1002 of the light emitted by the light source unit 100 to the second sub-element 2002, and reflect the first polarized beam 1001 of the light to the first sub-element 2001. FIG. 9 The polarization splitting elements shown have the same features, which will not be described in detail here.

[0202] For example, FIG. 15As shown, the beam splitter element 300 further includes a reflective element 320, which is located on a side of the polarization beam splitter element 310 away from the optical waveguide element 200 and is configured to reflect the first polarized light beam 1001 into the first sub-element 2001. FIG. 9 The reflective elements shown have the same features, which will not be described again.

[0203] For example, FIG. 15 As shown, the second polarized light is in the P polarization state and the first polarized light is in the S polarization state as an example for explanation. FIG. 15 As shown, after the unpolarized light emitted by the light source unit 100 passes through the polarization splitting element 310 with polarization splitting function, the transmitted light includes P-polarized light, and the reflected light includes S-polarized light (and vice versa). The transmitted P-polarized light enters the second sub-element 2002, and the reflected S-polarized light is then reflected by the reflective element 320 to the first sub-element 2001. The S-polarized light and the P-polarized light are output through the optical coupling sections of their respective sub-optical waveguide components. For example, the S-polarized light is directly output through the first optical coupling section 241, and the P-polarized light is output through the second optical coupling section 242. It is then converted to S-polarized light through the polarization conversion element 400 and then output through the first sub-element 2001, thereby converting the unpolarized light emitted by the light source unit into light of the same polarization.

[0204] For example, the polarization conversion element may be a half-wave plate, but the disclosed embodiment is not limited thereto, and it only needs to convert the second polarized light into the first polarized light.

[0205] For example, FIG. 15 As shown, first sub-element 2001 can be located on a side of second sub-element 2002 away from light source unit 100, so that transmitted second polarized light enters the second sub-element and reflected first polarized light enters the first sub-element, but the present invention is not limited thereto. The light source unit can also be located between the first and second sub-element, or on a side of the first sub-element away from the second sub-element, depending on actual needs.

[0206] FIG. 16 for FIG. 15 An example of a backlight source is shown in FIG. FIG. 16As shown, the optical outcoupling unit 240 includes a transflective element array 220. Each transflective element of the transflective element array 220 is configured to reflect a portion of light propagating through the transflective element toward a predetermined area, while transmitting another portion through the waveguide medium 210 for continued total internal reflection propagation. The waveguide medium 210 includes a main surface. The transflective element array 220 includes a plurality of transflective elements 221 arranged along a first direction parallel to the main surface. Each transflective element 221 forms a first angle with the main surface. The angle between the light propagating through total internal reflection in the waveguide medium 210 and the main surface forms a second angle. The difference between the first angle and the second angle is no greater than 10 degrees. For example, the difference between the first angle and the second angle is no greater than 5 degrees. For example, the first angle and the second angle are equal, meaning that the light rays propagating through total internal reflection in the waveguide medium 210 are parallel to the transflective elements 221, so that the light rays are reflected only once in each transflective element. This prevents light rays parallel to the transflective elements from being transmitted and reflected therethrough, thereby improving light uniformity and preventing stray light. Of course, the disclosed embodiments are not limited thereto. The angle between the transflective element and the light rays propagating through total internal reflection can also be greater than 5 degrees. In this case, by providing a reflective structure on the side of the optical waveguide element away from the display panel, the stray light that has escaped can be reflected back, thereby improving the uniformity of the light emitted from the optical waveguide element.

[0207] For example, FIG. 16 As shown, the transflective element array 220 in the first light outcoupling portion 241 includes a plurality of first transflective elements 2211 arranged along a first direction, and the transflective element array 220 in the second light outcoupling portion 242 includes a plurality of second transflective elements 2212 arranged along the first direction.

[0208] For example, FIG. 16 As shown, the first polarized light beam 1001 transmitted to the first transflective element 2211 has a third angle with the first transflective element 2211 during total internal reflection. The second polarized light beam 1002 transmitted to the second transflective element 2212 has a fourth angle with the second transflective element 2212. The difference between the third and fourth angles is no greater than 5 degrees. For example, if the third and fourth angles are equal, the angle of the polarized light entering each sub-element can be adjusted based on the tilt angle of the transflective element in each sub-element. For example, setting the angles between different sub-elements and their corresponding polarized light to be the same can facilitate the manufacture of the sub-elements and the adjustment of the incident light angle.

[0209] For example, FIG. 16As shown, when the total reflection propagation direction of the first polarized light beam 1001 entering the first sub-element 2001 is the same as the total reflection propagation direction of the second polarized light beam 1002 entering the second sub-element 2002, the angle between the first transflective element 2211 and the second transflective element 2212 can be no greater than 5 degrees. For example, the first transflective element 2211 can be parallel to the second transflective element 2212 to facilitate the manufacture of the optical waveguide element.

[0210] For example, FIG. 16 As shown, the angles between the first transflective element 2211 and / or the second transflective element 2212 and the first direction are both acute angles or obtuse angles. FIG. 16 The direction indicated by the arrow in the X direction is the first direction, and the total internal reflection propagation direction of the first polarized light beam 1001 entering the first sub-element 2001 is the same as the total internal reflection propagation direction of the second polarized light beam 1002 entering the second sub-element 2002. When the total internal reflection propagation direction of each polarized light beam is the same as the first direction, the angle between each transflective element and the first direction is acute. When the total internal reflection propagation direction of each polarized light beam is opposite to the first direction, the angle between each transflective element and the first direction is obtuse. The angle between the transflective element and the first direction is related to the total internal reflection propagation direction of the polarized light beam.

[0211] For example, FIG. 16 As shown, the first transflective element 2211 is configured to have a greater reflectivity for the first polarized light beam 1001 than for the second polarized light beam 1002 , and a greater transmittance for the second polarized light beam 1002 than for the first polarized light beam 1001 .

[0212] The arrangement of the transflective elements in the embodiment of the present disclosure can be FIG. 9 The arrangement of the transflective elements in the illustrated examples has the same features, which will not be described in detail here.

[0213] For example, FIG. 16 As shown, light emitted from the second sub-element 2002 may or may not pass through the transflective element array 220 in the first sub-element 2001, and this is not limited in the present embodiment. For example, when polarized light emitted from the second sub-element passes through the transflective element array in the first sub-optical waveguide element, the transflective element array in the first sub-element has a higher transmittance for the polarized light emitted from the second sub-element.

[0214] For example, the embodiments of the present disclosure are not limited to the light outcoupling portion being an array of transflective elements. For example, the light outcoupling portion can also be at least one of a surface grating, a volume grating, a blazed grating, a prism, a reflective structure, and a light emitting grid point. Through at least one of the reflection, refraction, and diffraction effects, the total reflection condition of the light will be destroyed, causing the light to be emitted from the optical waveguide element.

[0215] For example, FIG. 17 A partial structure diagram of a backlight is provided for another example according to another embodiment of the present disclosure. FIG. 17 The example shown is different from FIG. 15 The difference between the example shown and FIG. 17 The positional relationship between the first sub-element and the second sub-element is different. As FIG. 17 As shown, the first sub-element 2001 includes an outlight surface, and the first sub-element 2001 and the second sub-element 2002 do not overlap in the direction perpendicular to the outlight surface (i.e., the Y direction) (for example, they can just abut or have a certain distance), which can not only reduce the thickness of the backlight, but also reduce the degree of weakening of the edge light intensity of the light waveguide element by setting the length of each sub-element to be smaller.

[0216] For example, as FIG. 17 As shown, the first sub-element 2001 and the second sub-element 2002 are arranged along the first direction, and the light source part 100 can be located between the first sub-element 2001 and the second sub-element 2002, but is not limited thereto. For example, when the light source part 100 is located between the first sub-element 2001 and the second sub-element 2002, the total reflection propagation directions of the first polarized light beam 1001 and the second polarized light beam 1002 are opposite, at this time, the transmissive and reflective element in the first sub-element 2001 and the transmissive and reflective element in the second sub-element 2002 are not parallel, for example, one of them has an acute angle with the first direction, and the other has an obtuse angle with the first direction, so as to realize the coupling-out of the light by the transmissive and reflective element.

[0217] For example, FIG. 18 A partial structure diagram of a backlight is provided for another example according to another embodiment of the present disclosure. FIG. 18 The example shown is different from FIG. 15 The difference between the example shown and FIG. 18 As shown, the first light coupling-out part 241 and the second light coupling-out part 242 are both located in the first sub-element 2001. In this example, the light incident to the light waveguide element is taken as an example of polarized light.

[0218] For example, as FIG. 18 As shown, the first sub-element 2001 includes the second light coupling-out part 242, the first sub-element 2001 includes an outlight surface, the first sub-element 2001 and the second sub-element 2002 overlap in the direction perpendicular to the outlight surface, the polarization conversion structure 400 is located on the light-incident side of the second light coupling-out part 242, the second polarized light entering the second sub-element 2002 propagates by total reflection in the second sub-element and is converted into first polarized light by the polarization conversion structure 400, and the converted first polarized light is coupled out by the second light coupling-out part 242.

[0219] For example, asFIG. 15-FIG. 17 As shown, the second sub-element 2002 is provided with a reflective structure 500. The second polarized light propagating through total reflection in the second sub-element 2002 enters the first sub-element 2001 after being converted by the polarization conversion structure 400 and reflected by the reflective structure 500. The polarization conversion structure can be provided in the optical waveguide element 200 or outside the optical waveguide element 200.

[0220] For example, the coupling method of the first optical coupling unit 241 to the first polarized light beam 1001 and the coupling method of the second optical coupling unit 242 to the second polarized light beam 1002 in this example can be the same as FIG. 15 The examples shown may be the same or different. For example, the light splitting element 300 in this example may be the same as FIG. 15 The features of the optical splitter elements in the examples shown are the same and will not be described in detail here. For example, the waveguide medium in the optical waveguide element of this example can be FIG. 15 The waveguide media in the examples shown have the same characteristics and are not described in detail here. For example, the first polarized light and the second polarized light in this example can be FIG. 18 The first polarized light and the second polarized light in the illustrated example have the same characteristics, which will not be described in detail here.

[0221] For example, FIG. 18 As shown, the first sub-element 2001 includes a light-emitting surface, and the first sub-element 2001 and the second sub-element 2002 partially or completely overlap in a direction perpendicular to the light-emitting surface (i.e., the Y direction). The polarization conversion structure 400 is located on the light-entering side of the second light coupling unit 242. The second polarized light beam 1002 entering the second sub-element 2002 is configured to propagate through total internal reflection within the second sub-element 2002 and, after passing through the polarization conversion structure 400, be coupled out by the second light coupling unit 242.

[0222] In the disclosed embodiments, by configuring the second polarized light to propagate by total internal reflection within the second sub-element, the second polarized light can be made more uniform, for example, with a more uniform distribution of light and dark. In the disclosed embodiments, disposing the first and second light coupling units within the same sub-element can reduce manufacturing costs and facilitate implementation.

[0223] For example, FIG. 18 As shown, the light incident side of the first light outcoupling portion 241 is located on the side of the first light outcoupling portion 241 away from the second light outcoupling portion 242 , and the light incident side of the second light outcoupling portion 242 is located on the side of the second light outcoupling portion 242 away from the first light outcoupling portion 241 .

[0224] For example, FIG. 18It is schematically shown that a gap is provided between the first light out-coupling part 241 and the second light out-coupling part 242, but it is not limited thereto, and there can also be no gap between the first light out-coupling part and the second light out-coupling part to prevent a dark area from appearing between the two light out-coupling parts. For example, the first light out-coupling part and the second light out-coupling part can also be arranged to overlap to improve the uniformity of the light emission.

[0225] For example, FIG. 18 It is schematically shown that the first sub-element 2001 and the second sub-element 2002 are separate structures, and the polarization conversion structure 400 is located in the second sub-element 2002, but it is not limited thereto, and the polarization conversion structure can also be located in the first sub-element, or between the first sub-element and the second sub-element, or when the first sub-element and the second sub-element are integrated, the polarization conversion structure can be located in the first sub-element and the second sub-element, or outside the first sub-element and the second sub-element, and the polarization conversion structure can be located on the light-in side of the second light out-coupling part, that is, the second polarization light propagating in the second sub-element is converted into first polarization light by the polarization conversion structure, and the first polarization light is coupled out by the second light out-coupling part.

[0226] For example, the second sub-element 2002 can include other light out-coupling parts (for example, the first sub-element and the second sub-element are separate structures), or can not include light out-coupling parts (for example, the first sub-element and the second sub-element are integrated), and the second sub-element is mainly configured to make the second polarization light propagate by total reflection therein.

[0227] For example, FIG. 18 It is schematically shown that the light-in side of the second light out-coupling part 242 in the first sub-element 2001 is provided with a third light in-coupling part 233, which can have the same features as the first light in-coupling part and the second light in-coupling part in the above-mentioned embodiments, but it is not limited thereto, and the light-in side of the second light out-coupling part 242 in the first sub-element 2001 can also not be provided with a light in-coupling part.

[0228] For example, the second polarization light can be converted into the first polarization light by the polarization conversion structure only once, for example, the polarization conversion structure can be a 1 / 2 wave plate. Of course, the embodiments of the present disclosure are not limited thereto, and the second polarization light can also be converted into the first polarization light by the polarization conversion structure twice, for example, the polarization conversion structure can be a 1 / 4 wave plate.

[0229] For example, as FIG. 19As shown, the polarization conversion structure 400 is arranged in the second sub-element 2002, and the second sub-element 2002 is further provided with a reflection structure 500 on the side away from the light source part 100. The second polarized light beam 1002 propagating by total reflection in the second sub-element 2002 is configured to pass through the polarization conversion structure 400 twice, and enters the first sub-element 2001 after being reflected by the reflection structure 500 once.

[0230] FIG. 18 For FIG. 19 An example diagram of the backlight is shown. As FIG. 19 As shown, taking the second polarized light beam 1002 as P-polarized light and the first polarized light as S-polarized light as an example, the non-polarized light emitted by the light source part 100 passes through the polarization beam splitting element 310 with polarization beam splitting function, transmits P-polarized light, and reflects S-polarized light (or vice versa). The transmitted P-polarized light enters the second sub-element 2002 through the second light in-coupling part 232, propagates by total reflection in the waveguide medium of the second sub-element 2002, propagates to the reflection structure 500 at the end face, and the reflected light no longer satisfies the total reflection condition, and the reflected light will leave the second sub-element 2002. The reflection structure 500 here can be regarded as a light out-coupling part of the second sub-element 2002. At the same time, the light in-coupling side of the reflection structure 500 is also provided with a polarization conversion structure 400. When the P-polarized light is reflected, it first passes through the polarization conversion structure 400, and the reflected light also passes through the polarization conversion structure 400 again before leaving the second sub-element 2002. That is, the P-polarized light passes through the polarization conversion structure 400 twice, and is then converted into S-polarized light. The converted S-polarized light enters the waveguide medium of the first sub-element 2001 through the third in-coupling part 233, is totally reflected, is transmitted to the second light out-coupling part 242, and is coupled out from the first sub-element 2001.

[0231] For example, as FIG. 19 As shown, the first light out-coupling part 241 and the second light out-coupling part 242 each include a transmissive-reflection element array 220, and each transmissive-reflection element 221 included in the transmissive-reflection element array 220 has an angle substantially equal to the angle of the light incident to the surface thereof. For example, the transmissive-reflection element array 220 in the first light out-coupling part 241 includes a plurality of first transmissive-reflection elements 2211 arranged along the first direction, and the transmissive-reflection element array 220 in the second light out-coupling part 242 includes a plurality of second transmissive-reflection elements 2212 arranged along the first direction. Since the total reflection propagation direction of the first polarized light beam 1001 incident to the first light out-coupling part 241 is opposite to the total reflection propagation direction of the converted first polarized light beam 1001’ incident to the second light out-coupling part 242, the first transmissive-reflection elements 2211 and the second transmissive-reflection elements 2212 are not parallel, i.e., the inclination directions of the two are different. For example, one of the first transmissive-reflection elements 2211 and the second transmissive-reflection elements 2212 has an acute angle with the first direction, and the other has an obtuse angle with the first direction.

[0232] For example, FIG. 20 The first sub-element and the second sub-element are schematically shown to be arranged at least partially overlapping in the Y direction, but are not limited thereto, and the first sub-element and the second sub-element can also not overlap in the Y direction.

[0233] For example, FIG. 20 A partial structure diagram of a backlight is provided for yet another example according to another embodiment of the present disclosure. FIG. 14 The shown example is different from FIG. 20 The shown example is different from

[0234] As FIG. 20 The light waveguide element 200 includes a first sub-element 2001 and a second sub-element 2002, the first sub-element 2001 includes the first light out-coupling part 241, and the second sub-element 2002 includes the second light out-coupling part 242. For example, FIG. 9 The first sub-element and the second sub-element are schematically shown to be arranged at least partially overlapping in the Y direction, but are not limited thereto, and the first sub-element and the second sub-element can also not overlap in the Y direction. FIG. 20 The sub-light waveguide elements can be the same structure, or can be different structures.

[0235] As FIG. 20 The light source part 100 is configured to make the light rays emitted thereby enter the first sub-element 2001, and the first polarized light in the light rays is coupled out by the first light out-coupling part 241, and the second polarized light in the light rays propagates in the first sub-element 2001 to the polarization conversion structure 400 to be converted into first polarized light; the first polarized light obtained after conversion by the polarization conversion structure 400 propagates in the second sub-element 2002 to the second light out-coupling part 242 to be coupled out by the second light out-coupling part 242.

[0236] For example, the polarization conversion structure is arranged between the first sub-element and the second sub-element; or the first sub-element is provided with the polarization conversion structure, and the polarization conversion structure is located on a side of the first light out-coupling part away from the light entry side of the first sub-element; or the second sub-element is provided with the polarization conversion structure, and the polarization conversion structure is located on the light entry side of the second light out-coupling part.

[0237] As FIG. 15-FIG. 17As shown, the optical waveguide element 200 includes a first sub-element 2001 and a second sub-element 2002, the first sub-element 2001 is provided with a first light coupling-out portion 241, and the second sub-element 2002 is provided with a second light coupling-out portion 242. The non-polarized light emitted by the light source portion 100 is configured to enter the first sub-element 2001, and the first polarized light beam 1001 in the light is coupled out by the first light coupling-out portion 241, and the second polarized light beam 1002 in the light is configured to propagate in the first sub-element 2001 to the polarization conversion structure 400 to be converted into the first polarized light beam 1001'; the first polarized light beam 1001' converted by the polarization conversion structure 400 is configured to propagate in the second sub-element 2002 to the second light coupling-out portion 242 to be coupled out by the second light coupling-out portion 242. The first light coupling-out portion not only can play the effect of coupling out light, but also can perform light splitting on the non-polarized light entering the light source portion, so that the polarization splitting of the non-polarized light entering the light source portion by the light coupling-out portion in the optical waveguide element can omit the setting of the light splitting device to save the volume of the backlight source.

[0238] For example, the coupling-out manner of the first light coupling-out portion 241 to the first polarized light beam 1001 and the coupling-out manner of the second light coupling-out portion 242 to the second polarized light beam 1002 in the present example can be the same as that in the example shown in FIG. 15 For example, the waveguide medium in the optical waveguide element in the present example can have the same characteristics as the waveguide medium in the example shown in FIG. 15 For example, the first polarized light and the second polarized light in the present example can have the same characteristics as the first polarized light and the second polarized light in the example shown in FIG. 20 For example, the first polarized light and the second polarized light in the present example can have the same characteristics as the first polarized light and the second polarized light in the example shown in

[0239] For example, as shown in FIG. 20 For example, as shown in FIG. 20 For example, as shown in

[0240] For example, as shown in FIG. 21As shown, the first sub-element 2001 includes a light exit surface, and the first sub-element 2001 and the second sub-element 2002 at least partially overlap in a direction perpendicular to the light exit surface. However, the first sub-element and the second sub-element can also be arranged along the total reflection propagation direction of the light rays, for example, along the X direction. For example, the first sub-element and the second sub-element can also not overlap in the direction perpendicular to the light exit surface, the first light out-coupling portion in the first sub-element can couple out the first polarized light and transmit the second polarized light, and the second light out-coupling portion in the second sub-element can couple out the converted first polarized light.

[0241] FIG. 20 For FIG. 21 An example diagram of the backlight is shown. As FIG. 21 As shown, the first light out-coupling portion 241 and the second light out-coupling portion 242 each include a trans-reflective element array 220, and each trans-reflective element 221 included in the trans-reflective element array 220 has an angle substantially equal to the angle of the light rays incident to the surface thereof. For example, the trans-reflective element array 220 in the first light out-coupling portion 241 includes a plurality of first trans-reflective elements 2211 arranged along the first direction, and the trans-reflective element array 220 in the second light out-coupling portion 242 includes a plurality of second trans-reflective elements 2212 arranged along the first direction. Since the total reflection propagation direction of the first polarized light beam 1001 incident to the first light out-coupling portion 241 is opposite to the total reflection propagation direction of the converted first polarized light beam 1001' incident to the second light out-coupling portion 242, the first trans-reflective elements 2211 and the second trans-reflective elements 2212 are not parallel, i.e., the tilt directions of the two are different, for example, the angle between one of the first trans-reflective elements 2211 and the second trans-reflective elements 2212 and the first direction is an acute angle, and the angle between the other and the first direction is an obtuse angle.

[0242] The embodiments of the present disclosure are not limited thereto, and when the first sub-element and the second sub-element are arranged along the X direction, the total reflection propagation direction of the first polarized light incident to the first light out-coupling portion is the same as the total reflection propagation direction of the converted first polarized light incident to the second light out-coupling portion, and the first trans-reflective elements and the second trans-reflective elements can be substantially parallel, i.e., the tilt directions of the two are the same, for example, the angles between the first trans-reflective elements and the second trans-reflective elements and the first direction are both acute angles or obtuse angles.

[0243] For example, the first trans-reflective elements 2211 can be elements having a higher reflectivity to the first polarized light beam 1001 and a higher transmissivity to the second polarized light beam 1002 to achieve light splitting of the non-polarized light. For example, the second trans-reflective elements 2212 can be trans-reflective elements without polarization selection characteristics, or can be elements having a higher reflectivity to the first polarized light, and the embodiments of the present disclosure are not limited thereto.

[0244] For example, as FIG. 21As shown, the light emitted by the light source part 100 is configured to propagate by total reflection in at least one of the first sub-element 2001 and the second sub-element 2002. For example, FIG. 21 The schematic diagram shows that the light propagates by total reflection in both the first sub-element 2001 and the second sub-element 2002, but is not limited thereto. The light entering the first sub-element from the light source part can also propagate in the first sub-element in a manner other than total internal reflection, such as directly along a straight line and then output by the transmission-reflection element through the transmission-reflection effect.

[0245] For example, the polarization conversion structure 400 can be arranged between the first sub-element 2001 and the second sub-element 2002. For example, the polarization conversion structure 400 can also be arranged in the first sub-element 2001 and located on the side of the first light out-coupling part 241 away from the light source part 100. For example, the polarization conversion structure 400 can also be arranged in the second sub-element 2002 and located on the light-in side of the second light out-coupling part 242.

[0246] For example, FIG. 21 The schematic diagram shows that the first sub-element and the second sub-element are integrated into one structure, and the polarization conversion structure is located in the integrated structure and on the light-out side of the first light out-coupling part and the light-in side of the second light out-coupling part. The embodiments of the present disclosure are not limited thereto. The polarization conversion structure can also be located at a position other than the first sub-element and the second sub-element, as long as it is located on the light-out side of the first light out-coupling part and the light-in side of the second light out-coupling part.

[0247] For example, as FIG. 18 to FIG. 19 shown, the optical waveguide element 200 further includes a reflection structure 500 located on the light-in side of the polarization conversion structure 400. The reflection structure 500 is configured to change the propagation direction of the second polarized light beam 1002 so that it is incident on the polarization conversion structure 400.

[0248] For example, the polarization conversion structure 400 can be a 1 / 2 wave plate. The polarization conversion structure in this example can be the same as the polarization conversion structure in the example shown in FIG. 22 , and will not be described again here.

[0249] Compared with the scheme in which all the light emitted by the light source part is transmitted and output through the same waveguide medium, the scheme of the present disclosure in which the light emitted by the light source part is divided into different polarization states and then transmitted and output through different waveguide media can further improve the brightness uniformity of the output light.

[0250] For example, FIG. 22 A partial structure schematic diagram of a backlight source according to an example of still another embodiment of the present disclosure is provided. As FIG. 22As shown, the backlight source includes a light source part 100 and a light waveguide plate 2000, the light waveguide plate 2000 includes a light uniformization part 250 and a light waveguide element 200, the light waveguide element 200 includes a light exit surface, and the light uniformization part 250 and the light waveguide element 200 are arranged in sequence in a direction parallel to the light exit surface. The light source part 100 is configured to make the light emitted by the light source part 100 enter the light waveguide element 200 after multiple total reflections in the light uniformization part 250, and then exit from the light exit surface of the light waveguide element 200.

[0251] For example, the number of times of the multiple total reflections is not less than 5. For example, the number of times of the multiple total reflections can be 5-20. For example, the number of times of the multiple total reflections can be 6-12. For example, the number of times of the multiple total reflections can be 6-8.

[0252] For example, the light uniformization part 250 includes a light entrance end and a light exit end, and the light entrance end and the light exit end are arranged along the extension direction of the light exit surface; and the thickness of the light uniformization part 250 in the direction perpendicular to the light exit surface is not greater than the thickness of the light waveguide element 200 in the arrangement direction. In this way, the light uniformization part can increase the number of times of total reflection of the totally reflected light by setting a smaller thickness.

[0253] For example, the light waveguide element 200 includes a waveguide medium 210 and a light out-coupling part 240. The light waveguide element 200 further includes the light uniformization part 250, and the light of the light source part 100 reaches the light out-coupling part 240 after passing through the light uniformization part 250, and the light entering the light waveguide element 200 is configured to propagate by 8-11 times of total reflection in the light uniformization part 250.

[0254] For example, the refractive index of the light uniformization part 250 is greater than the refractive index of the waveguide medium 210 in the light waveguide element 200. By adjusting the refractive index of the light uniformization part, the total reflection critical angle of the light propagating by total reflection can be adjusted, and the number of times of total reflection can be increased when the total reflection critical angle is small.

[0255] For example, the light waveguide plate 2000 is an integrated structure. For example, the light uniformization part 250 and the waveguide medium 210 are an integrated structure. For example, the light uniformization part 250 can be located between the light out-coupling part 240 and the light source part 100. The embodiment of the present disclosure can improve the uniformity of the light before being transmitted to the light out-coupling part by arranging the light uniformization part on the light entrance side of the light out-coupling part of the waveguide medium, that is, the light is first homogenized and then outputted to obtain the surface light source light with uniform brightness.

[0256] The above-mentioned "the light uniformization part and the waveguide medium are an integrated structure" can mean that the light uniformization part and the waveguide medium are the same structure formed by one-step process with the same material, or can mean that the light uniformization part and the waveguide medium are connected together by bonding or other fixing methods. For example, the light uniformization part and the waveguide medium can be made of the same refractive index material, or can be made of different refractive index materials, and the embodiment of the present disclosure does not limit this.

[0257] For example, FIG. 1A to FIG. 21 The light homogenizing part shown can also be set FIG. 1A to FIG. 21 In any of the examples shown, the uniformity of the light output from the backlight source can be further improved. For example, the light outcoupling portion in this embodiment can be connected to FIG. 1A to FIG. 21 The optical coupling portion in any of the examples shown has the same features, which will not be described in detail here. For example, the waveguide medium in this embodiment can be FIG. 1A to FIG. 21 The waveguide medium in any of the examples shown has the same characteristics, which will not be described in detail here. FIG. 22 The light source parts in any of the examples shown have the same features, which will not be described in detail here.

[0258] For example, FIG. 23 As shown, the length of the light homogenizing portion 250 along the X direction may be no less than the length of the transflective element array serving as the optical outcoupling portion 240 along the X direction. The disclosed embodiments are not limited thereto, and the length of the light homogenizing portion 250 along the X direction may be 1 / 3 to 2 / 3 of the length of the transflective element array serving as the optical outcoupling portion 240 along the X direction.

[0259] For example, FIG. 22 for FIG. 23 The cross-sectional structure diagram of the backlight source is shown in FIG. FIG. 23 As shown, in this embodiment, the light coupling portion 230 may be provided or not provided. FIG. 1A to FIG. 21 As shown, the light coupling portion 230 provided in this embodiment can be FIG. 23 The light coupling portion provided in any of the examples shown has the same features, which will not be described in detail here.

[0260] For example, FIG. 23 As shown, the light homogenizing portion 250 can be disposed between the light coupling portion 230 and the light coupling portion 240 of the optical waveguide element 200 , or between the light coupling portion and the light source portion, which is not limited in the embodiment of the present disclosure.

[0261] For example, FIG. 23 As shown, the light emitted by the light source unit 100 first enters the light homogenizing unit 250 through the light coupling unit 230, is transmitted in the light homogenizing unit 250 and is gradually homogenized; the homogenized light beam is then coupled out through the light coupling unit (e.g., a transflective element array) 240, for example, converted into a collimated parallel light beam for output.

[0262] For example, FIG. 22As shown, the light homogenizer 250 can perform multiple total reflections on the light entering it, for example 8 to 11 times, to evenly distribute the light beam and achieve a uniform light distribution effect. The light after homogenization continues along the total reflection path to the optical coupling unit 240. Through the transmission and reflection of the optical coupling unit 240, it is converted into collimated light and then emitted, forming collimated parallel light with uniform brightness. Therefore, the light homogenizer needs to be placed before the optical coupling unit.

[0263] For example, FIG. 23 and FIG. 24 As shown, the light outcoupling unit 240 includes a plurality of light outcoupling sub-units 2401 arranged along a first direction (i.e., the X direction), and the light homogenizing unit 250 and the light outcoupling unit 240 are arranged along the first direction. For example, the light homogenizing unit 250 and the light outcoupling unit 240 are arranged on a plane parallel to the XZ plane.

[0264] For example, FIG. 24 FIG. 1 is a schematic diagram of a partial structure of a backlight source according to another example of yet another embodiment of the present disclosure. FIG. 24 As shown, the optical waveguide element 200 includes a light-emitting surface 001, an optical coupling portion 240 and a waveguide medium 210 both overlap with a light homogenizing portion 250 in a direction perpendicular to the light-emitting surface 001, and a gap medium 260 is provided between the waveguide medium 210 and the light homogenizing portion 250. The refractive indexes of the waveguide medium 240 and the light homogenizing portion 250 are both greater than the refractive index of the gap medium 260. By arranging the optical coupling portion and the waveguide medium to overlap with the light homogenizing portion in the disclosed embodiment, the area occupied by the light homogenizing portion can be reduced, thereby increasing the area of ​​the light-emitting surface of the backlight source to obtain uniform surface light.

[0265] For example, FIG. 24 As shown, the light homogenizing unit 250 may be located on a side of the light coupling unit 240 away from the light emitting surface 001 .

[0266] For example, the gap medium 260 can be air or other solid media (eg, optical glue) with a refractive index lower than that of the light homogenizer 250 and the waveguide medium 210 so that the light transmitted in the light homogenizer and the waveguide medium meets the total reflection condition.

[0267] For example, the gap medium 260 may be a transparent medium or a non-transparent medium, which is not limited in the embodiment of the present disclosure.

[0268] For example, FIG. 24 As shown, the length of the light homogenizing portion 250 along the X direction may be no less than the length of the transflective element array serving as the optical coupling portion 240 along the X direction to achieve a better light homogenizing effect. The embodiments of the present disclosure are not limited thereto. The length of the light homogenizing portion 250 along the X direction may be 1 / 3 to 2 / 3 of the length of the transflective element array serving as the optical coupling portion 240 along the X direction.

[0269] For example,FIG. 24 As shown, a connecting portion 270 is further provided between the optical waveguide element 200 and the light homogenizing portion 250 , and the connecting portion 270 connects the light input end of the optical waveguide element 200 and the light output end of the light homogenizing portion 250 , so that the light from the light homogenizing portion 250 enters the optical waveguide element 200 through the connecting portion 270 .

[0270] For example, FIG. 24 As shown, the connecting portion 270 includes a light modulating portion 271 , which is configured to destroy the total reflection condition of the light propagating in the light homogenizing portion 250 so that the light transmitted in the light homogenizing portion 250 can enter the optical waveguide element 200 .

[0271] For example, FIG. 24 As shown, the connecting portion 270 further includes a reflective surface 272, and the reflective surface 272 is configured to reflect the light in the light homogenizing portion 250 into the optical waveguide element 200. In the embodiment of the present disclosure, the connecting portion may include at least one of a light modulating portion and a reflective surface. FIG. 24 The connecting portion is schematically shown to include a dimming portion and a reflective surface, but is not limited thereto. The connecting portion may also include only the dimming portion, or only the reflective surface.

[0272] For example, the aforementioned connecting portion 270 is further disposed between the waveguide medium 210 and the light homogenizing portion 250. The connecting portion 270 connects the waveguide medium 240 and the light homogenizing portion 250 at one end away from the light incident side of the light homogenizing portion 250, so that light from the light homogenizing portion 250 enters the waveguide medium 210 through the connecting portion 270. For example, the connecting portion 270 is located on a side of the gap medium 260 away from the light source portion 100. For example, the light source portion 100 and the connecting portion 270 are located on opposite sides of the gap medium 260 in the X direction.

[0273] For example, FIG. 24 As shown, the connecting portion 270 is located on a side away from the light incident side of the light homogenizing portion 250. For example, the connecting portion 270 and the light source portion 100 are respectively located on either side of the light homogenizing portion 250. For example, the connecting portion 270 and the light source portion 100 are respectively located on either side of the waveguide medium 210. For example, the connecting portion 270 is located on the light exit side of the light homogenizing portion 250 and on the light incident side of the waveguide medium 210.

[0274] For example, FIG. 24 As shown, the connecting portion 270 includes a light modulating portion 271 , which is configured to destroy the total reflection condition of the total reflection propagating light in the light homogenizing portion 250 so that the light transmitted in the light homogenizing portion 250 can enter the waveguide medium 210 .

[0275] For example, the dimming unit 271 can be an optical element with a different refractive index from the waveguide medium 210, such as optical glue, which destroys the total reflection condition and allows the light to enter the light coupling unit (such as a transflective element array) located on the side of the light homogenizing unit 250 facing the display panel.

[0276] For example, the light adjusting portion 271 can simultaneously serve as the light out-coupling portion of the light homogenizing portion 250 and the light in-coupling portion of the waveguide medium, or can only serve as the light out-coupling portion of the light homogenizing portion 250, or only serve as the light in-coupling portion of the waveguide medium, and the embodiments of the present disclosure do not make any limitation in this regard.

[0277] For example, as shown in FIG. 2B, the connecting portion 270 further includes a reflecting surface 272 configured to reflect the light rays emitted from the light homogenizing portion 250 towards the waveguide medium 210. FIG. 24

[0278] For example, as shown in FIG. 2B, the connecting portion 270 further includes a reflecting surface 272 configured to reflect the light rays emitted from the light homogenizing portion 250 towards the waveguide medium 210. FIG. 22-24 For example, as shown in FIG. 2B, the connecting portion 270 further includes a reflecting surface 272 configured to reflect the light rays emitted from the light homogenizing portion 250 towards the waveguide medium 210.

[0279] FIG. 25 For example, as shown in FIG. 2B, the connecting portion 270 further includes a reflecting surface 272 configured to reflect the light rays emitted from the light homogenizing portion 250 towards the waveguide medium 210.

[0280] For example, the display panel provided by the embodiments of the present disclosure can be a liquid crystal display panel, such as a transmissive liquid crystal display panel or a reflective liquid crystal display panel, which can form an image in cooperation with the light provided by the backlight. For example, the light provided by the backlight can be converted into image light after passing through the liquid crystal display panel (e.g., a liquid crystal screen). The embodiments of the present disclosure are not limited in this regard, and the display panel can also be an electrowetting screen or a silicon-based liquid crystal display element, etc. Regardless of the type of display panel, it can be matched with the backlight provided by the embodiments of the present disclosure to form a display device that is thin and has uniform light emission.

[0281] For example, the display device provided by the embodiments of the present disclosure can be a display device as shown in FIG. 3A. As shown in FIG. 3A, the display device includes a display panel 300 and a backlight 100. The display panel 300 can be a liquid crystal display panel, such as a transmissive liquid crystal display panel or a reflective liquid crystal display panel, which can form an image in cooperation with the light provided by the backlight 100. For example, the light provided by the backlight 100 can be converted into image light after passing through the liquid crystal display panel (e.g., a liquid crystal screen). The embodiments of the present disclosure are not limited in this regard, and the display panel can also be an electrowetting screen or a silicon-based liquid crystal display element, etc. Regardless of the type of display panel, it can be matched with the backlight provided by the embodiments of the present disclosure to form a display device that is thin and has uniform light emission. FIG. 25 For example, the display device provided by the embodiments of the present disclosure can be a display device as shown in FIG. 3A. As shown in FIG. 3A, the display device includes a display panel 300 and a backlight 100. The display panel 300 can be a liquid crystal display panel, such as a transmissive liquid crystal display panel or a reflective liquid crystal display panel, which can form an image in cooperation with the light provided by the backlight 100. For example, the light provided by the backlight 100 can be converted into image light after passing through the liquid crystal display panel (e.g., a liquid crystal screen). The embodiments of the present disclosure are not limited in this regard, and the display panel can also be an electrowetting screen or a silicon-based liquid crystal display element, etc. Regardless of the type of display panel, it can be matched with the backlight provided by the embodiments of the present disclosure to form a display device that is thin and has uniform light emission. FIG. 1A to FIG. 24 ​​As shown, the display device further comprises a light diffusion element 30 between the light waveguide element 200 and the display panel 10, the light diffusion element 30 is configured to diffuse the light rays emitted by the light waveguide element 200, i.e., the light diffusion element 30 is configured to diffuse the light beams passing through the light diffusion element 20. The backlight source in the embodiments of the present disclosure can be any one of the backlight sources shown in any one of the examples. FIG. 25

[0282] For example, the light diffusion element 30 can also be arranged on the light-emitting side of the display panel 10 and configured to diffuse the image light emitted by the display panel 10. For example, the light diffusion element 30 is arranged close to the display panel 10 to improve the imaging effect.

[0283] For example, FIG. 26 The number of light diffusion elements is schematically shown as 1, but is not limited thereto, and can also be multiple and arranged at intervals from each other to further improve the dispersion effect of the light beams. The light diffusion element is schematically shown as being located on the back side of the display panel in the embodiments of the present disclosure, but is not limited thereto and can also be located on the display side of the display panel. For example, the light diffusion element can be attached to the surface of the display surface of the display panel.

[0284] For example, the light diffusion element 30 is configured to diffuse the light beams passing through the light diffusion element 30 but does not change the optical axis of the light beams. The above-mentioned "optical axis" refers to the center line of the light beams.

[0285] For example, after the incident light beams pass through the light diffusion element 30, the light beams are diffused into light spots having a specific size and shape in the propagation direction and the energy distribution of the light spots is homogenized. The size and shape of the light spots can be accurately controlled by the specific microstructure designed on the surface of the light beam diffusion structure 30. The above-mentioned specific shape can include but is not limited to linear, circular, elliptical, square, and rectangular.

[0286] For example, the light diffusion element 30 can not distinguish between the front and back surfaces. For example, the propagation angle and the spot size after the light beams are diffused determine the brightness and the visible area of the final imaging. The smaller the diffusion angle, the higher the imaging brightness and the smaller the visible area; vice versa.

[0287] For example, the light diffusion element 30 includes at least one of a diffractive optical element and a scattering optical element.

[0288] For example, the light diffusion element 30 can be a scattering optical element such as a homogenizing sheet, a diffusion sheet, etc. with a relatively low cost. When the light beams pass through the scattering optical element such as the homogenizing sheet, scattering occurs and a small amount of diffraction also occurs, but the scattering plays a major role. After the light beams pass through the scattering optical element, a relatively large light spot is formed.

[0289] ​For example, the light diffusion element 30 can also be a diffractive optical element (DOE) that controls the diffusion effect more accurately, such as a beam shaper and the like. For example, the diffractive optical element plays a light beam expansion role by diffraction through designing specific microstructures on the surface, and the light spot is small and the size and shape of the light spot are controllable.

[0290] For example, FIG. 26 A partial structure schematic diagram of a display device provided for another example according to another embodiment of the present disclosure is shown. As shown in FIG. 1A to FIG. 24 The display device further includes a light converging element 40 located between the light waveguide element 200 and the light diffusion element 30, and configured to converge light rays emitted from the light waveguide element 200 to the display panel 10. The backlight source in the embodiment of the present disclosure can be FIG. 26 the backlight source shown in any of the examples.

[0291] For example, as shown in FIG. 26 The light converging element 40 is configured to control the direction of the collimated light rays emitted from the light waveguide element 200, and to gather the light rays to a predetermined range, so as to further gather the light rays and improve the utilization rate of the light rays. The predetermined range can be a point, such as the focal point of a convex lens, or a smaller area. The purpose of setting the light converging element is to uniformly adjust the direction of the collimated light rays output by the light waveguide element to the predetermined range, so as to improve the utilization rate of the light rays.

[0292] For example, the light converging element 40 can be a lens or a lens combination, such as at least one lens, such as a convex lens, a Fresnel lens, or a lens combination, and the like, FIG. 26 which is schematically shown by taking a convex lens as an example.

[0293] For example, as shown in FIG. 26 The light converging element 40 can gather the collimated light rays output by the light waveguide element 200 to a certain range, and the light diffusion element 30 can diffuse the gathered light rays. The embodiment of the present disclosure cooperates the light converging element and the light diffusion element to provide high light efficiency while also expanding the viewable range.

[0294] For example, as shown in FIG. 26 In the embodiment of the present disclosure, the light converging element 40 can gather and direct almost all light rays, so that the light rays can reach the eyebox area 003 of the user, and thus the collimated light beams output by the light waveguide element 200 are convenient to control to adjust the direction of the light rays. For example, the area where the observer needs to view the imaging, i.e., the eyebox area 003, can be preset according to actual needs, which refers to the area where the observer's eyes are located and can see the image displayed by the display device, and can be a planar area or a stereoscopic area.

[0295] For example, FIG. 27 As shown, light emitted by the light source unit 100 is converted into uniformly emitted collimated light by the optical waveguide element 200. After passing through the light converging element 40, the collimated light is concentrated and falls into the center of the eyebox area 003. The light is further diffused by the light diffusing element 30. The diffused light beam can cover the eyebox area 003, for example, just covering the eyebox area 003, achieving high light efficiency while not affecting normal observation. The present disclosure is not limited to this. The diffused light beam can also be larger than the eyebox area, at least completely covering the eyebox. For example, the present disclosure can provide a light diffusing element so that the diffused light beam just covers the eyebox area, in which case the light efficiency of the display device is maximized.

[0296] For example, FIG. 27 A schematic diagram of a partial structure of a display device provided in accordance with another example of yet another embodiment of the present disclosure. FIG. 26 The example shown is the same as FIG. 27 The difference between the examples shown is the positional relationship between the light converging element and the light waveguide element. FIG. 27 As shown, the light converging element 40 and the optical waveguide element 200 are integrated into one structure. By providing the light converging element and the optical waveguide element as an integrated structure, the disclosed embodiment not only reduces the thickness of the display device and facilitates installation, but also prevents unnecessary reflection of light at the interface between air and the optical waveguide element and / or the light converging element, thereby reducing or avoiding waste of light efficiency.

[0297] For example, FIG. 28 As shown, a transparent dielectric layer 50 is disposed between the light converging element 40 and the optical waveguide element 200. The refractive index of the transparent dielectric layer 50 is lower than that of the optical waveguide element 200 so as to satisfy the total internal reflection condition for light propagating in the waveguide medium. For example, the thickness of the transparent dielectric layer can be sufficiently small so that the light propagates in the waveguide medium in accordance with the total internal reflection condition.

[0298] For example, the transparent medium layer 50 may be a medium with relatively high transmittance, such as transparent optical adhesive, which can not only achieve bonding of the light converging element and the optical waveguide element, but also improve the transmittance of light.

[0299] For example, the light converging element 40 and the optical waveguide element 200 may be made of the same material or different materials, and the embodiment of the present disclosure does not limit this.

[0300] For example, FIG. 28A schematic diagram of the partial structure of a display device provided for another example according to another embodiment of the present disclosure. The light conversion device can be applied to a display device, in which the light emitted by the backlight source is non-polarized light, or the light emitted by the light source portion to the optical waveguide element is non-polarized light, and the display panel is configured to generate image light using the first polarized light or the second polarized light. The backlight source here can be the backlight source that meets this condition in the above-mentioned embodiment. The "non-polarized light" here means that the light emitted by the light source portion can have multiple polarization characteristics at the same time but does not show a unique polarization characteristic. For example, the light emitted by the light source portion can be considered to be a synthesis of two mutually perpendicular polarization states, that is, the non-polarized light emitted by the light source portion can be decomposed into two mutually perpendicular polarization states. The polarized light that can be used by the display panel here can refer to polarized light that can be incident on the inside of the display panel, or it can refer to polarized light required for the display panel to form a specific polarization state image light, etc.

[0301] For example, the light conversion device can be set in multiple positions, for example, configured to recycle light emitted by the light source and send the recycled light into the optical waveguide element, and / or recycle light emitted by the optical waveguide element and send the recycled light into the display panel.

[0302] For example, FIG. 28 As shown, the liquid crystal display panel 10 may include an array substrate (not shown), an opposing substrate (not shown), and a liquid crystal layer (not shown) located between the array substrate and the opposing substrate. For example, the liquid crystal display panel further includes a first polarizing layer 10-1 disposed on a side of the array substrate away from the opposing substrate, and a second polarizing layer 10-2 disposed on a side of the opposing substrate away from the array substrate. For example, the backlight source 20 is configured to provide backlight to the liquid crystal display panel 10, and the backlight is converted into image light after passing through the liquid crystal display panel 10.

[0303] For example, the polarization axis direction of the first polarizing layer 10-1 and the polarization axis direction of the second polarizing layer 10-2 are perpendicular to each other, but the present invention is not limited thereto. For example, the first polarizing layer 10-1 can pass a first linearly polarized light, and the second polarizing layer 10-2 can pass a second linearly polarized light, but the present invention is not limited thereto. For example, the polarization direction of the first linearly polarized light is perpendicular to the polarization direction of the second linearly polarized light.

[0304] For example, only light of a specific polarization state can pass through the first polarization layer 10-1 between the liquid crystal layer and the backlight source 20 and enter the interior of the liquid crystal display panel, and be used to form an image. For example, when the light emitted by the backlight source 20 is unpolarized light, only a maximum of 50% of the light emitted by the backlight source 20 can be used by the image generation unit, and the remaining light will be wasted or absorbed by the liquid crystal layer to generate heat. In the embodiment of the present disclosure, by providing a light conversion device on the light incident side of the display panel, almost all of the unpolarized light emitted by the backlight source can be converted into light of a specific polarization state that can be used by the display panel, effectively improving the utilization rate of the light emitted by the backlight source.

[0305] For example, FIG. 28 As shown, the light conversion device 50 is located on a side of the display panel 10 facing the optical waveguide element 200 . FIG. 28 The light conversion device 50 is schematically shown to be located between the light converging element 40 and the optical waveguide element 200, but is not limited thereto. The light conversion device can also be located between the optical waveguide element and the light source portion, between the light converging element and the light diffusing element, or between the light diffusing element and the display panel. The light conversion device is located on the light incident side of the display panel so that the light incident on the display panel is of a specific polarization state.

[0306] For example, the light conversion device includes a beam splitting element 51, a direction-changing element 52, and a polarization conversion element 53. For example, the beam splitting element 51 is configured to split the light incident on the beam splitting element 51 into a first polarized light beam 101 and a second polarized light beam 102 having different polarization states. The first polarized light beam 101 is configured to be emitted toward the display panel 10, and the second polarized light beam 102 is emitted toward the direction-changing element 52. The direction-changing element 52 is configured to change the propagation direction of the light incident on the direction-changing element 52 so that it is emitted toward the display panel 10. The polarization conversion element 53 is configured to convert the polarized light in the first polarized light beam 101 and the second polarized light beam 102 that cannot be used by the display panel 10 into polarized light that can be used by the display panel 10 before reaching the display panel 10.

[0307] For example, FIG. 28 As shown, the first polarized light beam 101 and the second polarized light beam 102 are both linearly polarized light. For example, the display panel 10 includes a first polarizing layer 10-1 located on a side of the display panel 10 close to the light source unit 100, and the polarization axis of the first polarizing layer 10-1 is parallel to the polarization direction of the first polarized light beam 101 or the second polarized light beam 102. The polarization conversion element 53 is configured to convert polarized light in the first polarized light beam 101 and the second polarized light beam 102 whose polarization direction is not parallel to the polarization axis into polarized light with a polarization direction parallel to the polarization axis before reaching the display panel 10. FIG. 28The polarization direction of the second polarized light beam 102 is parallel to the polarizing axis of the first polarizing layer 10-1, but is not limited thereto, and can also be parallel to the polarizing axis of the first polarizing layer.

[0308] For example, as shown in FIG. 1, the backlight 20 emits non-polarized light, and the display panel 10 can use S-polarized light (the second polarized light beam 102). The beam splitting element 51 reflects S-polarized light and transmits P-polarized light (the first polarized light beam 101), and the direction changing element 52 can reflect S-polarized light. The S-polarized light in the light emitted by the backlight 20 is reflected by the beam splitting element 51, the reflected S-polarized light is reflected by the direction changing element 52, and then emitted to the display panel 10. The P-polarized light in the light emitted by the backlight 20 is transmitted by the beam splitting element 51, and then converted into S-polarized light by the polarization conversion element 53. Thus, the non-polarized light emitted by the backlight is converted into S-polarized light that can be used by the display panel. FIG. 28 For example, the beam splitting element 51 can have the function of transmitting light of one characteristic and reflecting light of another characteristic, for example, the beam splitting element 51 can have the function of transmitting light of one polarization state and reflecting light of another polarization state, and the beam splitting element can achieve beam splitting by using the above-mentioned transmission and reflection characteristics.

[0309] For example, the beam splitting element 51 can be a transmission and reflection film, which achieves the beam splitting function by transmitting part of the light and reflecting another part of the light. For example, the transmission and reflection film can transmit the first polarized light beam 101 in the light emitted by the backlight 20, and reflect the second polarized light beam 102 in the light emitted by the backlight 20.

[0310] For example, the transmission and reflection film can be an optical film with polarization transmission and reflection function, specifically, an optical film that can split non-polarized light into two mutually perpendicular polarized lights by transmission and reflection. The above-mentioned optical film can be composed of a plurality of film layers with different refractive indexes according to a certain stacking order, and the thickness of each film layer is about 10-1000 nm. The material of the film layer can be inorganic dielectric material, for example, metal oxide and metal nitride, or high polymer material, for example, polypropylene, polyvinyl chloride or polyethylene.

[0311] For example, the beam splitting element 51 can be a component formed by coating or pasting a film on a transparent substrate. For example, the beam splitting element 51 can be a substrate coated or pasted with a transmission and reflection film with the function of reflecting S-polarized light and transmitting P-polarized light, for example, a reflective polarized light enhancement film (Dual Brightness Enhance Film, DBEF) or a prism film (Brightness Enhancement Film, BEF). The embodiments of the present disclosure are not limited thereto, for example, the beam splitting element can also be an integrated component.

[0312] ​

[0313] For example, the direction changing element 52 is configured to reflect the second polarized light beam 102 incident to the direction changing element 52 to the display panel 10.

[0314] For example, the direction changing element 52 can be a reflective element for reflecting the second polarized light beam 102 out of the beam splitting element 51 to the display panel 10. Since the polarizing axis of the polarizing layer 210 of the display panel 10 is parallel to the polarization direction of the second polarized light beam 102, the second polarized light beam 102 emitted from the direction changing element 52 to the display panel 10 can be directly utilized by the display panel 10.

[0315] For example, the direction changing element 52 can be a common reflective plate such as a metal or glass reflective plate, or a substrate with a reflective film coated or attached thereon with the reflective S-polarized light characteristic. For example, the direction changing element 52 can also have a transmissive and reflective characteristic, and have the same transmissive and reflective characteristic as the transmissive and reflective film included in the beam splitting element 51, i.e., the characteristic of reflecting S-polarized light and transmitting P-polarized light. The present disclosure is not limited in this regard, and the direction changing element 52 can reflect S-polarized light only.

[0316] For example, the polarization conversion element 53 can be a phase delay film, which rotates the polarization direction of the first polarized light beam 101 incident thereto by 90 degrees so that the light emitted from the phase delay film to the display panel 10 is the second polarized light beam 102 that can be utilized by the display panel 10. For example, the polarization conversion element 53 can be a 1 / 2 wave plate.

[0317] For example, the polarization conversion element can be disposed in close contact with the beam splitting element. For example, a transparent substrate can be disposed between the beam splitting element and the polarization conversion element, and the beam splitting element and the polarization conversion element are respectively in close contact with two opposite surfaces of the transparent substrate for easy installation. The present disclosure is not limited in this regard, and for example, the beam splitting element can be directly in close contact with the surface of the polarization conversion element to achieve a thin and light image source.

[0318] For example, as shown in FIG. 5, the polarization conversion element 53 is located on the side of the beam splitting element 51 away from the direction changing element 50. FIG. 29 For example, as shown in FIG. 5, the polarization conversion element 53 is located on the side of the beam splitting element 51 away from the direction changing element 50.

[0319] FIG. 29 For example, as shown in FIG. 5, the polarization conversion element 53 is located on the side of the beam splitting element 51 away from the direction changing element 50.

[0320] For example, as shown in FIG. 5, the polarization conversion element 53 is located on the side of the beam splitting element 51 away from the direction changing element 50. FIG. 28 A schematic diagram of a light conversion device in a display device according to yet another example of yet another embodiment of the present disclosure is provided. FIG. 28 The light conversion device shown in FIG. 5 is similar to​FIG. 30 The difference between the light conversion device shown in FIG. 1 is the position of the polarization conversion element and the polarization state of light that can be used by the display panel. The characteristics of the beam splitting element 51, the direction changing element 52 and the polarization conversion element 53 in the light conversion device can be different from those in FIG. FIG. 30 The features of the components shown are the same and will not be repeated here.

[0321] For example, FIG. 28 A schematic diagram of a light conversion device in a display device is provided according to yet another example of yet another embodiment of the present disclosure. FIG. 28 The light conversion device shown is FIG. 31 The difference between the light conversion device shown in FIG. 1 is that the position of the polarization conversion element and the polarization state of light that can be used by the display panel are different, and the polarization light reflected by the direction changing element 52 is different. The characteristics of the beam splitting element 51 and the polarization conversion element 53 in the light conversion device can be different. FIG. 31 The features of the components shown are the same and will not be repeated here.

[0322] For example, FIG. 29 A schematic diagram of a light conversion device in a display device is provided according to yet another example of yet another embodiment of the present disclosure. FIG. 29 The light conversion device shown is FIG. 31 The difference of the light conversion device shown is that the light in this example passes through the polarization conversion element 53 twice, while FIG. 28 The light in the example shown passes through the polarization conversion element 53 only once, and the polarization reflected by the direction-changing element 52 is different.

[0323] For example, FIG. 32 As shown, the polarization conversion element 53 is located between the direction changing element 52 and the beam splitting element 51, and is configured to convert the second polarized light beam 102 reflected from the beam splitting element 51 to the direction changing element 52 into a third polarized light 103. The third polarized light 103 is reflected by the direction changing element 52 and converted into a first polarized light beam 101 after passing through the polarization conversion element 53. The converted first polarized light beam 101 is emitted toward the display panel 10.

[0324] For example, the polarization conversion element 53 may be a phase retardation film, such as a quarter-wave plate, which can convert the second polarized light beam 102 incident thereon, such as linearly polarized light, into a third polarized light beam 103, such as circularly polarized light or elliptically polarized light, so that the polarized light incident on the direction-changing element 52 after passing through the phase retardation film is no longer linearly polarized light. The third polarized light beam 103 incident on the direction-changing element 52 is redirected by the direction-changing element 52 so as to propagate toward the display panel 10. Before reaching the display panel 10, the third polarized light beam 103 passes through the polarization conversion element 53 again to be converted into the first polarized light beam 101 that can be used by the display panel 10.

[0325] For example, the features of the beam splitting element 51 and the direction changing element 52 in the light conversion device in this example can be the same as FIG. 32 The features of the corresponding elements shown are the same and will not be described again here.

[0326] FIG. 26 The diagram is a partial structural diagram of a head-up display provided according to another embodiment of the present disclosure. FIG. 25 The head-up display is schematically shown to include FIG. 27 to FIG. 31 The display device shown, but not limited thereto, may also include FIG. 32 ,or FIG. 32 The embodiments of the present disclosure do not limit the display device shown in any example.

[0327] like FIG. 32 As shown, the head-up display further includes a reflective imaging unit 60 located on the light-emitting side of the display panel 10. The reflective imaging unit 60 is configured to reflect light emitted from the display panel 10 toward the eyebox area 003 while transmitting ambient light. A user located in the eyebox area 003 can view the image 004 of the display panel 10 reflected by the reflective imaging unit 60, as well as the surrounding scenery located on the side of the reflective imaging unit 60 away from the eyebox area 003. For example, when image light emitted from the display panel 10 is incident on the reflective imaging unit 60, the light reflected by the reflective imaging unit 60 is incident on the user, such as the eyebox area 003 where the driver's eyes are located. The user can then observe a virtual image formed, for example, outside the reflective imaging unit, while maintaining their view of the external environment.

[0328] For example, the aforementioned eyebox area 003 refers to the planar area within which the user's eyes are located and within which the image displayed on the heads-up display can be seen. For example, if the user's eyes are displaced a certain distance from the center of the eyebox area, such as up or down, or left or right, the user's eyes will still be within the eyebox area and the user will still be able to see the image displayed on the heads-up display.

[0329] For example, FIG. 33 As shown, the reflective imaging portion 60 may be a windshield (eg, windshield) or an imaging window of a motor vehicle, corresponding to a windshield head-up display (W-HUD) and a combined head-up display (C-HUD), respectively.

[0330] For example, FIG. 33 As shown, the reflective imaging portion 60 can be a flat plate that forms a virtual image through mirror reflection; it can also be a curved surface, such as a windshield or a transparent imaging plate with curvature, which will provide a longer imaging distance.

[0331] ​ FIG. 1 is an exemplary block diagram of a traffic device according to another embodiment of the present disclosure. ​As shown, the traffic device includes a head-up display provided by at least one embodiment of the present disclosure. The front window (for example, the front windshield) of the traffic device is reused as the reflection imaging part 60 of the head-up display.

[0332] For example, the traffic device can be various appropriate traffic tools, for example, can include various types of land traffic devices such as cars, or can be water traffic devices such as ships, or can be air traffic devices such as airplanes, the driving position of which is provided with a front window and the image is transmitted onto the front window through a vehicle-mounted display system.

[0333] It should be noted that, for the sake of clarity, the thickness of the layers or regions is exaggerated or reduced in the drawings used to describe the embodiments of the present disclosure, that is, these drawings are not drawn according to the actual proportion.

[0334] Although the present disclosure has been described in detail with general description and specific embodiments above, some modifications or improvements can be made on the basis of the embodiments of the present disclosure, which is obvious to those skilled in the art. Therefore, these modifications or improvements made on the basis of not deviating from the spirit of the present disclosure, all belong to the scope of protection of the present disclosure.

[0335] The following points need to be explained:

[0336] (1) In the drawings of the embodiments of the present disclosure, only the structures related to the embodiments of the present disclosure are involved, and other structures can be referred to the general design.

[0337] (2) The features in the same embodiment and different embodiments of the present disclosure can be combined with each other without conflict.

[0338] The above description is only exemplary embodiments of the present disclosure, and is not intended to limit the protection scope of the present disclosure, and the protection scope of the present disclosure is determined by the appended claims.

Claims

1. A display device comprising: A display panel comprising a display surface and a back side opposite to the display surface; as well as a backlight source, located on the back side of the display panel, The backlight source includes a light waveguide element, the light waveguide element includes a light emitting surface and a transflective element array, the transflective element array includes a plurality of transflective elements, The backlight further includes a light source portion, wherein the light emitted by the light source portion is configured to undergo multiple total reflections at least at the light exit surface of the light waveguide element after entering the light waveguide element and sequentially propagate to the plurality of transflective elements of the transflective element array, wherein a portion of the light propagating to each transflective element of the transflective element array is reflected by the transflective element, exits the light exit surface of the light waveguide element, and then passes through the display panel, and another portion of the light propagating to each transflective element of the transflective element array passes through the transflective element and then continues to propagate in the light waveguide element; The optical waveguide element further includes a waveguide medium, and the light emitted by the light source portion enters the waveguide medium and propagates through total reflection in the waveguide medium; The angle between each of the transflective elements and the light-emitting surface is a first angle, the sum of the first angle and the critical angle of total reflection at which the light is totally reflected on the light-emitting surface is in the range of 60° to 120°, the angle between the light propagating by total reflection in the waveguide medium and the light-emitting surface is a second angle, and the difference between the first angle and the second angle is not greater than 10 degrees.

2. The display device according to claim 1, wherein The optical waveguide element includes a plurality of sub-optical waveguide elements, and the transflective element array includes a plurality of sub-transflective element arrays respectively located in the plurality of sub-optical waveguide elements; The backlight source further includes a spectroscopic element configured to split the light emitted by the light source portion and directed toward the optical waveguide element into a plurality of sub-beams and allow the plurality of sub-beams to enter the plurality of sub-optical waveguide elements respectively, and each sub-beam entering each sub-optical waveguide element is reflected by the sub-transflective element array located in each sub-optical waveguide element and exits the light-emitting surface of the optical waveguide element.

3. The display device according to claim 2, wherein: The plurality of sub-optical waveguide elements are overlapped in a direction perpendicular to the display surface of the display panel, or the plurality of sub-optical waveguide elements are arranged in a direction parallel to the display surface; The plurality of sub-optical waveguide elements include a first sub-optical waveguide element and a second sub-optical waveguide element.

4. The display device according to claim 3, wherein The light emitted by the light source unit and directed toward the optical waveguide element includes a first characteristic light and a second characteristic light having different characteristics. The spectroscopic element is configured to perform spectroscopic processing on the light emitted by the light source unit and directed toward the optical waveguide element, so that the first characteristic light obtained by the spectroscopic processing is incident on the first sub-optical waveguide element, and the second characteristic light obtained by the spectroscopic processing is incident on the second sub-optical waveguide element.

5. The display device according to claim 4, wherein The first characteristic light and the second characteristic light are respectively first polarized light and second polarized light with different polarization states; or, the first characteristic light and the second characteristic light are respectively first color light and second color light with different colors. The display device according to claim 5 , wherein: The plurality of sub-light beams obtained by performing the spectroscopic processing on the light include the first color light, the second color light, and the third color light, and the third color light is configured to enter one of the first sub-optical waveguide element and the second sub-optical waveguide element; or The multiple sub-light beams include the first color light, the second color light, and the third color light. The multiple sub-optical waveguide elements further include a third sub-optical waveguide element. The third color light is configured to enter the third sub-optical waveguide element and be reflected out of the third sub-optical waveguide element by the transflective element array located in the third sub-optical waveguide element.

7. The display device according to claim 4, wherein The transflective element in the first sub-optical waveguide element is a transflective element having a higher reflectivity for the first characteristic light than for the second characteristic light, and the transflective element in the second sub-optical waveguide element is a transflective element having a higher reflectivity for the second characteristic light than for the first characteristic light.

8. The display device according to claim 5, wherein The beam splitting element includes a polarization beam splitting element configured to reflect one of the first polarized light and the second polarized light and transmit the other of the first polarized light and the second polarized light; The beam splitting element further includes a reflective element configured to reflect one of the first polarized light and the second polarized light.

9. The display device according to claim 1, wherein The reflectivity of the transflective elements in the transflective element array sequentially arranged along the extension direction of the light emitting surface gradually increases or increases regionally in the propagation direction of the light; and / or The arrangement density of the transflective elements in the transflective element array that are sequentially arranged along the extension direction of the light emitting surface gradually increases or gradually increases regionally.

10. The display device according to claim 1, wherein At least one transflective element in the transflective element array includes a selective transmission film, the light entering the optical waveguide element includes a first light and a second light with different characteristics, and the selective transmission film is configured to have a reflectivity for the first light greater than a reflectivity for the second light, and a transmittance for the second light greater than a transmittance for the first light.

11. The display device according to claim 1, wherein The transflective element array includes a first transflective element group and a second transflective element group arranged along the extension direction of the light exit surface, each transflective element group includes transflective elements arranged along the extension direction of the light exit surface, and an inclination direction of the transflective elements of the first transflective element group relative to the light exit surface is not parallel to an inclination direction of the transflective elements of the second transflective element group relative to the light exit surface; wherein the light source unit includes a first light source unit and a second light source unit, the first light source unit and the second light source unit are respectively located on both sides of the transflective element array along the extension direction of the light emitting surface, the first transflective element group is configured to reflect the light emitted by the first light source unit and entering the optical waveguide element out of the optical waveguide element, and the second transflective element group is configured to reflect the light emitted by the second light source unit and entering the optical waveguide element out of the optical waveguide element; or The light source portion is located between the first transflective element group and the second transflective element group in the extending direction of the light emitting surface.

12. The display device according to any one of claims 1 to 11, wherein: At least some of the plurality of transflective elements included in the transflective element array are sequentially arranged along a first direction and extend along a second direction intersecting the first direction. The light source portion includes a plurality of sub-light sources arranged along the second direction, and the plurality of sub-light sources are configured to emit light that enters the at least partially transflective element.

13. The display device according to any one of claims 1 to 11, wherein: At least some of the plurality of transflective elements included in the transflective element array are sequentially arranged along a first direction and extend along a second direction intersecting the first direction. The light source unit includes a sub-light source and a plurality of beam expanders arranged along the second direction. The plurality of beam expanders are configured to expand the light emitted by the sub-light source along the second direction, and the expanded light is configured to be transmitted to the transflective element array.

14. The display device according to any one of claims 1 to 4, wherein: The light emitted by the light source unit includes a first polarized light and a second polarized light having different polarization states, and the display panel is configured to generate image light using the first polarized light or the second polarized light. The display device further comprises a light conversion device, which comprises a beam splitting element, a direction changing element and a polarization conversion element. The beam splitting element is located on a side of the display panel facing the optical waveguide element, and is configured to split the light incident on the beam splitting element into a first polarized light beam and a second polarized light beam with different polarization states, wherein the first polarized light beam is emitted toward the display panel, and the second polarized light beam is emitted toward the direction changing element; The direction-changing element is configured to change a propagation direction of a light beam incident on the direction-changing element so as to direct the light beam toward the display panel; The polarization conversion element is configured to convert a polarized beam of the first polarized beam and the second polarized beam that cannot be used by the display panel into a polarized beam that can be used by the display panel before reaching the display panel.

15. The display device according to claim 14, wherein The light conversion device is configured to recover light emitted by the light source and send the recovered light into the optical waveguide element, and / or recover light emitted by the optical waveguide element and send the recovered light into the display panel.

16. The display device according to claim 14, further comprising: At least one light diffusion element is located on at least one of the side where the display surface is located and the back side of the display panel, and is configured to diffuse light emitted from at least one of the display panel and the optical waveguide element.

17. The display device according to claim 16, further comprising: The light converging element is located between the light waveguide element and the display panel, and is configured to converge the light emitted from the light waveguide element and direct the converged light toward the at least one light diffusing element.

18. The display device according to claim 17, wherein: The light converging element includes at least one lens.

19. The display device according to claim 18, wherein The light converging element and the optical waveguide element are an integrated structure, and a transparent medium layer is provided between the light converging element and the optical waveguide element. The refractive index of the transparent medium layer is smaller than the refractive index of the optical waveguide element.

20. The display device according to any one of claims 1 to 11, wherein: The light emitting surface of the optical waveguide element and the display surface of the display panel are stacked in a direction perpendicular to the display surface, and the light source portion is located on the side of the optical waveguide element.

21. The display device according to any one of claims 1 to 11, wherein: The backlight source includes a light waveguide plate, which includes a light homogenizing portion and the light waveguide element. Light emitted by the light source undergoes multiple total reflections in the light homogenizing portion before entering the light waveguide element. The light waveguide plate is an integrated structure.

22. A head-up display comprising: The display device according to any one of claims 1 to 21; as well as The reflective imaging portion is located on the light-emitting side of the display device and is configured to reflect the light emitted by the display device to the observation area of ​​the head-up display.

23. A traffic device comprising the head-up display according to claim 22.

24. The transportation device according to claim 23, wherein: The reflective imaging portion includes a windshield of the traffic equipment.

Images