Light source device, display device, head-up display, and traffic equipment

Abstract

Embodiments of the present disclosure provide a light source device, a display device, a head-up display, and a traffic device. The light source device includes: a light source portion, the light emitted includes a first polarized light and a second polarized light with different polarization states; an optical waveguide element includes an optical coupling portion; and a polarization conversion structure. The optical coupling portion includes a first optical coupling portion and a second optical coupling portion, the first optical coupling portion is configured to couple out the first polarized light entering the optical waveguide element; the polarization conversion structure is configured to convert the second polarized light after entering the optical waveguide element into the first polarized light. In the present disclosure, the polarization conversion structure can convert the non-polarized light emitted from the light source portion into polarized light with a specific polarization state, and the polarized light can be used by the liquid crystal layer through a polarizer between the liquid crystal layer and the backlight source to improve the utilization rate of the light.

Description

Technical Field

[0001] At least one embodiment of the present disclosure relates to a light source device, a display device, a head-up display, and traffic equipment. Background Art

[0002] Currently, users have an increasing demand for display devices including backlight sources, and have also put forward more requirements for their display effects and portability. The backlight source in the display device has a certain degree of influence on the display effects and portability of the display device. Summary of the Invention

[0003] At least one embodiment of the present disclosure provides a light source device, a display device, a head-up display, and traffic equipment.

[0004] At least one embodiment of the present disclosure provides a light source device, including: a light source portion, wherein the light emitted by the light source portion includes a first polarized light and a second polarized light with different polarization states; and an optical waveguide element, including a light coupling portion. The light source unit is configured to transmit the light emitted by it in a reflective manner in the optical waveguide element after entering the optical waveguide element, and the light coupling unit is configured to couple out the light propagating in a reflective manner in the optical waveguide element; the light coupling unit includes a first light coupling unit and a second light coupling unit, the first light coupling unit is configured to couple out the first polarized light entering the optical waveguide element; the light source device also includes a polarization conversion structure, the polarization conversion structure is configured to convert the second polarized light entering the optical waveguide element into a first polarized light, the second light coupling unit is configured to couple out the converted first polarized light after the polarization conversion structure converts the second polarized light entering the optical waveguide element into the first polarized light; or the second light coupling unit is configured to couple the second polarized light entering the optical 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.

[0005] At least one embodiment of the present disclosure provides a display device, comprising: a display panel; and any light source device of the present disclosure, configured to provide backlight to the display panel.

[0006] At least one embodiment of the present disclosure provides a head-up display, comprising: any display device of the present disclosure; and a reflective imaging unit located on a light-emitting side of the display device and configured to reflect light emitted by the display device to an observation area of ​​the head-up display.

[0007] At least one embodiment of the present disclosure provides a traffic device including any head-up display of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] 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 only relate to some embodiments of the present disclosure, rather than limiting the present disclosure.

[0009] Figure 1A A schematic diagram of a partial cross-sectional structure of a display device provided according to an example of an embodiment of the present disclosure;

[0010] Figure 1B A schematic diagram of a partial cross-sectional structure of a display device provided according to an example of an embodiment of the present disclosure;

[0011] Figure 2 Based on Figure 1A A schematic diagram of a planar structure of a backlight source in the example shown;

[0012] Figure 3 Based on Figure 1A A schematic diagram of the planar structure of another backlight source in the example shown;

[0013] Figure 4A Based on Figure 1A A schematic diagram of the planar structure of another backlight source in the example shown;

[0014] Figure 4B Based on Figure 1A A schematic diagram of the planar structure of another backlight source in the example shown;

[0015] Figure 5 Based on Figure 1A A schematic diagram of the planar structure of another backlight source in the example shown;

[0016] Figure 6 This is an example where the light emitted from the transflective element array is not perpendicular to the main surface of the waveguide medium;

[0017] Figure 7 is a schematic diagram of a partial structure of a backlight source in another example according to an embodiment of the present disclosure;

[0018] Figure 8 is a schematic diagram of a partial structure of a backlight source in another example according to an embodiment of the present disclosure;

[0019] Figure 9 is a schematic diagram of a partial structure of a backlight source in another example according to an embodiment of the present disclosure;

[0020] Figure 10 is a schematic diagram of a partial structure of a backlight source in another example according to an embodiment of the present disclosure;

[0021] Figure 11 is a schematic diagram of a partial structure of a backlight source in another example according to an embodiment of the present disclosure;

[0022] Figure 12 is a schematic diagram of a partial structure of a backlight source in another example according to an embodiment of the present disclosure;

[0023] Figure 13 is a schematic diagram of a partial structure of a backlight source in another example according to an embodiment of the present disclosure;

[0024] Figure 14 A schematic diagram of a partial structure of a backlight source provided in accordance with an example of another embodiment of the present disclosure;

[0025] Figure 15 A schematic diagram of a partial structure of a backlight source provided in accordance with an example of another embodiment of the present disclosure;

[0026] Figure 16 for Figure 15 The backlight shown is an example diagram;

[0027] Figure 17 A schematic diagram of a partial structure of a backlight source provided in accordance with another example of another embodiment of the present disclosure;

[0028] Figure 18 A schematic diagram of a partial structure of a backlight source provided in accordance with another example of another embodiment of the present disclosure;

[0029] Figure 19 for Figure 18 The backlight shown is an example diagram;

[0030] Figure 20 A schematic diagram of a partial structure of a backlight source provided in yet another example according to another embodiment of the present disclosure;

[0031] Figure 21 for Figure 20 The backlight shown is an example diagram;

[0032] Figure 22 A schematic diagram of a partial structure of a backlight source provided in accordance with an example of yet another embodiment of the present disclosure;

[0033] Figure 23 for Figure 22 A schematic diagram of the cross-sectional structure of the backlight source shown;

[0034] Figure 24 A schematic diagram of a partial structure of a backlight source provided in accordance with another example of yet another embodiment of the present disclosure;

[0035] Figure 25 A schematic diagram of a partial structure of a display device provided according to an example of yet another embodiment of the present disclosure;

[0036] Figure 26A schematic diagram of a partial structure of a display device provided according to another example of yet another embodiment of the present disclosure;

[0037] Figure 27 A schematic diagram of a partial structure of a display device provided according to another example of yet another embodiment of the present disclosure;

[0038] Figure 28 A schematic diagram of a partial structure of a display device provided in accordance with another example of another embodiment of the present disclosure;

[0039] Figure 29 A schematic diagram of a light conversion device in a display device according to another example of another embodiment of the present disclosure is provided;

[0040] Figure 30 A schematic diagram of a light conversion device in a display device according to another example of another embodiment of the present disclosure is provided;

[0041] Figure 31 A schematic diagram of a light conversion device in a display device according to another example of another embodiment of the present disclosure is provided;

[0042] Figure 32 A schematic diagram of a partial structure of a head-up display provided according to another embodiment of the present disclosure; and

[0043] Figure 33 The present invention is an exemplary block diagram of a traffic device provided according to another embodiment of the present disclosure. DETAILED DESCRIPTION

[0044] To make the purpose, technical solutions, and advantages of the embodiments of the present disclosure more clear, the technical solutions of the embodiments of the present disclosure will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the described embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0045] Unless otherwise defined, technical or scientific terms used in this disclosure should have the ordinary meanings understood by people with ordinary skills in the field to which this disclosure belongs. The words "first", "second" and similar terms used in this disclosure do not indicate any order, quantity or importance, but are simply used to distinguish different components. The words "include" or "comprising" and similar terms mean that the elements or objects preceding the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects.

[0046] During their research, the inventors of this application discovered that a liquid crystal display device has two polarizers with different light transmission directions on either side of the liquid crystal layer. One of the polarizers is positioned between the liquid crystal layer and the backlight. This allows only light with a specific polarization state to pass through the polarizer between the liquid crystal layer and the backlight, enter the liquid crystal display panel, and be used to form an image. For example, when the backlight emits unpolarized light, only a maximum of 50% of the light emitted by the backlight can be used by the liquid crystal layer. The remaining light is wasted or absorbed by the liquid crystal layer to generate heat, resulting in low light utilization.

[0047] Embodiments of the present disclosure provide a light source device, a display device, a head-up display, and traffic equipment. The light source device includes: a light source unit, wherein the light emitted by the light source unit includes a first polarized light and a second polarized light with different polarization states; and an optical waveguide element including a light coupling unit. The light source unit is configured to transmit the light emitted by it in a reflective manner in the optical waveguide element after entering the optical waveguide element, and the light coupling unit is configured to couple out the light propagating in a reflective manner in the optical waveguide element; the light coupling unit includes a first light coupling unit and a second light coupling unit, the first light coupling unit is configured to couple out the first polarized light entering the optical waveguide element; the light source device also includes a polarization conversion structure, the polarization conversion structure is configured to convert the second polarized light entering the optical waveguide element into a first polarized light, the second light coupling unit is configured to couple out the converted first polarized light after the polarization conversion structure converts the second polarized light entering the optical waveguide element into the first polarized light; or the second light coupling unit is configured to couple the second polarized light entering the optical 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. In the present disclosure, the polarization conversion structure 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.

[0048] The light source device, display device, head-up display, and traffic equipment provided by the embodiments of the present disclosure are described below with reference to the accompanying drawings.

[0049] Figure 1A FIG. 1 is a schematic diagram of a partial cross-sectional structure of a display device according to an example of an embodiment of the present disclosure. Figure 1AAs 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.

[0050] like Figure 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.

[0051] 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.

[0052] For example, Figure 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.

[0053] 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.

[0054] For example, Figure 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.

[0055] 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.

[0056] 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.

[0057] For example, the collimating element may include a convex lens, a concave lens, or a Fresnel lens, or any combination of the above lenses.

[0058] For example, the collimating element may include a convex lens, and the light source may be disposed near the focus of the convex lens, whereby the divergent light emitted by the light source may be converted into parallel or nearly parallel collimated light after passing through the lens.

[0059] For example, Figure 2 Based on Figure 1A The schematic diagram of the planar structure of a backlight source in the example shown is shown in FIG. Figure 2 As shown, the light source included in the light source unit 100 can emit a one-dimensional light beam, that is, a light beam extending mainly in one dimension. For example, the light source unit 100 can include a strip light source, the cross section of which is approximately a one-dimensional line or a narrow strip.

[0060] For example, Figure 3 Based on Figure 1A The schematic diagram of the planar structure of another backlight source in the example shown is as follows. Figure 3 As shown, the transflective element array 220 includes a plurality of transflective element arrays 220, at least some of which are arranged sequentially along a first direction and extend along a second direction intersecting the first direction. For example, the number of transflective elements 221 may be two or more. The first direction may be the X direction, and the second direction may be the Z direction, but the present invention is not limited thereto. The first and second directions may be interchangeable.

[0061] For example, Figure 3 As shown, the light source of the light source portion 100 may include a plurality of sub-light sources 101 arranged along the second direction, and the plurality of sub-light sources 101 are configured to emit light that enters at least a portion of the transflective element 221. For example, the sub-light source 101 may be a point light source, and the light source portion 100 may be a combination of a plurality of point light sources, and the plurality of sub-light sources 101 are arranged in a linear shape along the second direction. Thus, the light beam emitted by the light source may also be considered a one-dimensional light beam. In the embodiment of the present disclosure, arranging a plurality of separate sub-light sources can facilitate the replacement and disassembly of each sub-light source. For example, when any sub-light source is damaged, it can be repaired by disassembling and replacing it separately, without having to replace the entire light strip like a strip light, thereby saving costs.

[0062] For example, Figure 4A Based on Figure 1A The schematic diagram of the planar structure of another backlight source in the example shown is as follows. Figure 4A As shown, the transflective element array 220 includes multiple transflective elements 221 extending along the second direction, the light source unit 100 includes multiple beam expanders 102 arranged along the second direction and a sub-light source 101 located on one side of the multiple beam expanders 102 in the second direction, the multiple beam expanders 102 are configured to expand the light emitted by the sub-light source 101 along the second direction, and the expanded light is configured to be transmitted to the transflective element array 220.

[0063] 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.

[0064] For example, Figure 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.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] For example, Figure 4B Schematic diagram of the structure of another backlight source. Figure 4B The backlight shown is Figure 4A The backlight shown differs in that the beam expander is located in the optical waveguide element.

[0069] For example, Figure 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.

[0070] 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.

[0071] For example, the light coupling portion 230 in the embodiment of the present disclosure may include at least one of a surface grating, a volume grating, a blazed grating, a prism and a reflective structure, and through at least one of reflection, refraction and diffraction effects, the light emitted by the light source enters the waveguide medium so that it meets the total internal reflection condition and is then conducted.

[0072] For example, Figure 1A As shown, the optical waveguide element 200 includes two opposing first and second main surfaces 211 and 212. The light coupling portion 230 may be disposed on the first and second main surfaces 211 and 212, or on a side surface connecting the two main surfaces. For example, the two main surfaces of the optical waveguide element may also be the two main surfaces of a waveguide medium. For example, the transflective element array is located between the first and second main surfaces. For example, light may propagate at least through total internal reflection on the first and / or second main surfaces, but may also experience partial non-total internal reflection, such as specular reflection.

[0073] For example, when the optical waveguide element includes multiple sub-optical waveguide elements, for example, the multiple sub-optical waveguide elements are overlapped and arranged perpendicular to the first main surface, the upper surface of the uppermost sub-optical waveguide element is the first main surface, and the lower surface of the lowermost sub-optical waveguide element is the second main surface.

[0074] For example, the first major surface 211 and the second major surface 212 include an upper surface 211 close to the display panel 10 and a lower surface 212 away from the display panel 10. The light coupling portion 230 can be disposed on the upper surface 211 or the lower surface 212 and located on the side of the transflective element array 220 facing the light source unit 100. For example, the first direction (X direction) and the second direction (Z direction) are parallel to the above-mentioned major surfaces.

[0075] For example, the waveguide medium 210 is made of a material capable of achieving a waveguide function, typically a transparent material having a refractive index greater than 1. For example, the material of the waveguide medium 210 may include one or more of silicon dioxide, lithium niobate, silicon-on-insulator (SOI), polymer, Group III-V semiconductor compounds, and glass.

[0076] For example, the waveguide medium 210 may be a planar substrate, a strip substrate, a ridge substrate, etc. For example, in at least one example of the embodiments of the present disclosure, the waveguide medium uses a planar substrate to form a uniform surface light source.

[0077] For example, Figures 1A to 3 As shown, the transflective element array 220 includes a plurality of transflective elements 221 arranged along the total reflection propagation direction of light. The above-mentioned "total reflection propagation direction of light" can refer to the overall (macroscopic) direction of light propagation, for example, Figure 1AIn the first direction (ie, X direction) shown, the light entering the optical waveguide element 200 is totally internally reflected at the two main surfaces of the waveguide medium 210 , so that the light propagates along the X direction to the transflective element array 220 .

[0078] For example, Figures 1A to 3 As shown, the transflective element 221 is configured to both transmit and reflect light. For example, when light that has been totally internally reflected within the waveguide medium 210 reaches the transflective element 221, it reflects there, and the angle of the reflected light no longer satisfies the total internal reflection condition, and thus exits the optical waveguide. The transmitted light then continues along the total internal reflection path, reaching the next transflective element 221, where it continues to reflect and transmit. The light reflected by the next transflective element 221 exits the optical waveguide element 200, and the light transmitted by the next transflective element 221 continues along the total internal reflection path. This process continues in this manner until it reaches the last transflective element 221.

[0079] For example, Figure 1A As shown, the transflective element 221 can be disposed in the waveguide medium 210 by plating or laminating. For example, the waveguide medium 210 can be divided into multiple cylinders with parallelogram cross-sections, and the transflective element 221 can be disposed between the spliced ​​cylinders. That is, the medium between adjacent transflective elements 221 can be the waveguide medium 210. For example, the waveguide medium 210 includes multiple waveguide sub-mediums arranged along a first direction and affixed to each other, with the transflective element 221 sandwiched between adjacent waveguide sub-mediums. Each waveguide sub-medium is configured to cause total internal reflection of light, and the transflective element is configured to destroy the total internal reflection condition of a portion of light by reflection, thereby coupling the portion of light out of the optical waveguide element.

[0080] For example, the present embodiment is described using an example in which the multiple transflective elements 221 in the transflective element array 220 are parallel to each other. In this case, the light emitted from the transflective element array is parallel light. However, the present embodiment is not limited to this. The multiple transflective elements in the transflective element array can also be non-parallel. By adjusting the angles between the multiple transflective elements, the light emitted from the transflective element array can be adjusted to convergent light or divergent light.

[0081] For example, Figure 1AAs 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.

[0082] 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.

[0083] For example, the first angle and the second angle may both be acute angles.

[0084] For example, Figure 1B A schematic diagram of the partial structure of another display device. Figure 1B and Figure 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.

[0085] For example, Figures 1A to 3As shown, the disclosed embodiment schematically illustrates that the orthographic projections of adjacent transflective elements 221 on the main surface are connected to each other, which can prevent the formation of a dark area between the two transflective elements where no light is emitted. However, the orthographic projections of adjacent transflective elements on the main surface can partially overlap to prevent light from being weakened at the edges of the transflective elements. The overlapping of the transflective elements can also make the emitted light more uniform.

[0086] For example, Figures 1A to 3 As shown, along the direction of total internal reflection propagation of light in the waveguide medium 210, multiple transflective elements 221 are evenly arranged, and their reflectivity gradually increases. For example, the closer the transflective element 221 is to the light source unit 100, the lower its reflectivity. For example, the reflectivity of the transflective elements arranged sequentially along the extension direction of the light output surface in the transflective element array gradually increases in the direction of light propagation, or increases regionally. For example, the arrangement density of the transflective elements arranged sequentially along the extension direction of the light output surface in the transflective element array gradually increases, or increases regionally. For example, the regional increase can be two or more regions, and the reflectivity of the transflective elements in these different regions is different and gradually increases.

[0087] The uniform arrangement described above can refer to an arrangement where adjacent transflective elements are arranged so that their orthographic projections touch each other, or an arrangement where their orthographic projections partially overlap. Since light gradually reflects out of the waveguide medium during propagation, the light intensity gradually decays. Therefore, by configuring the transflective properties of each transflective element differently, for example, by gradually increasing the reflectivity of each transflective element along the path of total internal reflection propagation, the intensity of light reflected from each transflective element can be made more uniform, resulting in more uniform light output from each portion of the waveguide medium 210.

[0088] For example, along the direction of total reflection propagation of light in the waveguide medium, the arrangement density of multiple transflective elements gradually increases. For example, the closer the part is to the light source, the smaller the arrangement density of the transflective elements. For example, the position with low arrangement density can be to set adjacent transflective elements so that their orthographic projections are connected to each other, and the position with high arrangement density can be to set adjacent transflective elements so that their orthographic projections partially overlap. For example, the position with low arrangement density can be to set adjacent transflective elements so that their orthographic projections overlap each other, and the overlapping part is small, and the position with high arrangement density can be to set adjacent transflective elements so that their orthographic projections overlap each other, and the overlapping part is large. The embodiment of the present disclosure can also make the intensity of light reflected by each transflective element uniform by setting the transflective properties of each transflective element to be the same or almost the same, and adjusting the arrangement density of the transflective element.

[0089] For example, Figure 5 Based on Figure 1A A schematic diagram of the planar structure of another backlight source in the example shown. Figure 5 The backlight shown is Figure 3The backlights shown differ in that the reflectivity of the transflective elements in the transflective element array varies. Figure 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.

[0090] 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.

[0091] 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.

[0092] 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.

[0093] The light entering the optical waveguide component can be unpolarized light or polarized light in two polarization states. "Unpolarized light" here means that the light emitted by the light source can simultaneously have multiple polarization characteristics but does not exhibit a single polarization characteristic. For example, the light emitted by the light source can be considered to be composed of two mutually perpendicular polarization states. In other words, the unpolarized light emitted by the light source can be decomposed into two mutually perpendicular polarization states.

[0094] For example, the selective film can be a brightness enhancement film (BEF), which has a high reflectivity for one polarized light and a high transmittance for another polarized light (for example, the selective film has a high reflectivity for S-polarized light and a high transmittance for P-polarized light). The transflective element can utilize the selectivity of polarization transflection so that the light is gradually reflected out of the optical waveguide element by the transflective element.

[0095] For example, Figure 1A As shown, when the light emitted from the transflective element array 220 does not meet the total reflection condition, the emission direction may be perpendicular to the main surface of the waveguide medium 210 .

[0096] Figure 6 This is an example where the light emitted from the transflective element array is not perpendicular to the main surface of the waveguide medium. Figure 6 As shown, when the angle of the light incident on the transflective element changes, and / or the angle between the transflective element and the main surface changes, the light emitted from the transflective element array may not be perpendicular to the main surface of the waveguide medium.

[0097] In the disclosed embodiments, light emitted from the transflective element array can be perpendicular or non-perpendicular to the main surface of the waveguide medium. Light emitted from different transflective elements can be parallel or nearly parallel, forming a collimated beam. In the disclosed embodiments, using a thin optical waveguide element to convert light output from a light source into collimated surface light can reduce the thickness of the display device.

[0098] Figure 7 Schematic diagram of the partial structure of a backlight source in another example according to an embodiment of the present disclosure. Figure 7 The example shown is the same as Figure 1A The difference between the examples shown is the number of light source parts and the arrangement of the transflective elements. The positional relationship between adjacent transflective elements can be different. Figure 1A The examples shown are the same. Figure 7 As shown, the transflective element array 220 includes a first transflective element group 2201 and a second transflective element group 2202 arranged along a first direction. Each transflective element group includes a plurality of transflective elements 221 arranged along the first direction. The transflective elements 221 of different transflective element groups are not parallel. For example, Figure 7It 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.

[0099] For example, Figure 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.

[0100] For example, Figure 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.

[0101] 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.

[0102] 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.

[0103] For example, Figure 8 Schematic diagram of the partial structure of a backlight source in another example according to an embodiment of the present disclosure. Figure 8 The example shown is the same as Figure 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. Figure 8As 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 the transflective element array 220 in a first direction. Both side surfaces of each transflective element 221 can reflect light entering from the first light source unit 110 or the second light source unit 120, so that both main surfaces of the optical waveguide element serve as light-emitting surfaces.

[0104] For example, the reflectivity of the transflective element located in the middle and / or near the middle is greater than the reflectivity of the transflective elements located on either side, so that the light emitted from the optical waveguide element has better uniformity. The backlight source in this example can be used in scenarios where light output from two sides is required, such as billboards.

[0105] For example, Figure 9 FIG. 1 is a schematic diagram of a partial structure of a backlight source in another example according to an embodiment of the present disclosure. Figure 9 As shown, the backlight further includes a beam splitter 300 located between the light source unit 100 and the optical waveguide element 200. The beam splitter 300 is configured to split the light emitted from the light source unit 100 toward the optical waveguide element 200 into a plurality of sub-beams. For example, the beam splitter 300 may split the light emitted from the light source unit 100 toward the optical waveguide element 200 into two or three sub-beams. The present disclosure is not limited thereto, and further sub-beams may be formed. For example, the beam splitter 300 may be a prism.

[0106] For example, Figure 9 As shown, the optical waveguide element 200 includes a plurality of sub-optical waveguide elements 201. The plurality of sub-light beams are configured to enter the plurality of sub-optical waveguide elements 201 and be reflected out of the optical waveguide element 200 by the transflective element array 221 located in each sub-optical waveguide element 201. For example, the transflective element array includes a plurality of sub-transflective element arrays located in the plurality of sub-optical waveguide elements. For example, the plurality of sub-transflective element arrays correspond one-to-one to the plurality of sub-optical waveguide elements.

[0107] For example, the number of the plurality of sub-optical waveguide elements 201 may be the same as the number of the plurality of sub-light beams. In this case, the plurality of sub-light beams are configured to enter the corresponding sub-optical waveguide elements one by one. The disclosed embodiments are not limited thereto. The number of the plurality of sub-optical waveguide elements may also be less than the number of the plurality of sub-light beams. In this case, at least two sub-light beams enter the same sub-optical waveguide element.

[0108] For example, the thickness of the plurality of sub-optical waveguide elements 201 is smaller than Figure 1AIn the illustrated embodiment, the thickness of the optical waveguide element is determined. Light originally transmitted through a single optical waveguide element is split and then coupled into multiple thinner waveguide elements. The light transmitted through the thinner waveguide elements increases the number of total internal reflections, resulting in a more uniform light distribution. For example, the uniformity in this embodiment can refer to uniform light brightness. Light emitted by a typical light source (e.g., a point light source) is brighter in the center and dimmer at the edges. After the light from the light source passes through the optical waveguide element, the collimated light coupled out is also brighter in the center and dimmer at the edges. Adjusting the brightness of the collimated light is difficult. Therefore, by improving the uniformity of the light before it enters or is coupled out of the optical waveguide element, a uniform surface light source can be obtained. For example, increasing the number of total internal reflections can improve brightness uniformity, so thinner optical waveguide elements can be used to increase the number of total internal reflections.

[0109] In the embodiment of the present disclosure, the uniformity of the light output from the backlight source can be further improved by dividing the light from the light source into multiple sub-beams and providing multiple sub-light waveguide elements to couple out the multiple sub-beams entering therein.

[0110] For example, the plurality of sub-optical waveguide elements may be independent structures or may be integrated on the same substrate.

[0111] For example, each sub-optical waveguide element includes a waveguide medium, and the refractive index of the waveguide medium in different sub-optical waveguide elements may be the same or different, which is not limited in the embodiment of the present disclosure.

[0112] For example, the number and arrangement of the transflective elements included in the transflective element array in each sub-optical waveguide element may be the same or different, and the embodiment of the present disclosure does not limit this.

[0113] For example, each sub-optical waveguide element may or may not include a light coupling portion. For example, when each sub-optical waveguide element includes a light coupling portion, the light coupling portions of different sub-optical waveguide elements may be identical, for example, all using a geometric method (e.g., a non-grating coupling method such as prism coupling or reflective structure coupling), or may be different, and the present disclosure is not limited to this.

[0114] For example, Figure 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.

[0115] 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.

[0116] 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.

[0117] 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.

[0118] For example, Figure 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.

[0119] For example, Figure 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.

[0120] 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.

[0121] For example, Figure 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.

[0122] 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.

[0123] 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.

[0124] 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.

[0125] 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.

[0126] For example, the transmitted P-polarized light passes through the second light coupling portion 232 in the second sub-optical waveguide component 2012 and enters the second sub-optical waveguide component 2012. The reflected S-polarized light is reflected by the reflective element 320 and then enters the first light coupling portion 231 in the first sub-optical waveguide component 2011, thereby entering the first sub-optical waveguide component 2011. The S-polarized light and the P-polarized light pass through the transflective element arrays in their respective waveguide components and are output as collimated light, thereby achieving the effect of converting a normal light source into a uniform surface light source.

[0127] For example, Figure 9 As shown, multiple sub-optical waveguide elements are arranged in an overlapping manner perpendicular to the display surface of the display panel, thereby increasing the brightness of the backlight source and improving the uniformity of the light. The above-mentioned overlapping arrangement includes a complete overlapping arrangement and a partial overlapping arrangement. That is, the orthographic projections of the multiple sub-optical waveguide elements on a plane parallel to the light output surface of the optical waveguide element can completely overlap or partially overlap, and the embodiments of the present disclosure are not limited to this. Figure 9 It is schematically shown that the first sub-optical waveguide component and the second sub-optical waveguide component are completely overlapped.

[0128] For example, Figure 9 As shown, the first optical sub-waveguide element 2011 and the second optical sub-waveguide element 2012 overlap in a direction perpendicular to the display surface of the display panel, that is, the first optical sub-waveguide element 2011 and the second optical sub-waveguide element 2012 overlap in the Y direction, and the light emitted from the second optical sub-waveguide element 2012 passes through the first optical sub-waveguide element 2011 and then emits to the display panel. For example, Figure 9 As shown, the light emitted from the second sub-optical waveguide component 2012 may pass through the transflective element array in the first sub-optical waveguide component 2011, or may not pass through the transflective element array in the first sub-optical waveguide component 2011, and this embodiment of the present disclosure does not limit this.

[0129] For example, when the light emitted from the second optical waveguide sub-component passes through the transflective element array in the first optical waveguide sub-component, the transflective element array in the first optical waveguide sub-component has a higher transmittance for the transmitted light.

[0130] For example, Figure 9 As shown, the first polarized light beam 1001 transmitted to the transflective element of the first optical sub-waveguide component 2011 forms a third angle with the transflective element, and the second polarized light beam 1002 transmitted to the transflective element of the second optical sub-waveguide component 2012 forms a fourth angle with the transflective element. The difference between the third and fourth angles is no greater than 5 degrees. Both the third and fourth angles may refer to the angles between a light beam incident on and transmitted through the surface of a transflective element and the element.

[0131] For example, if the third and fourth angles are equal, the angle of polarized light entering the sub-optical waveguide components can be adjusted based on the tilt angle of the transflective element in each sub-optical waveguide component. For example, setting the angles between different sub-optical waveguide components and their corresponding polarized light to be the same can also facilitate the fabrication of the sub-optical waveguide components and the adjustment of the incident light angle.

[0132] For example, Figure 9 As shown, when the total internal reflection propagation direction of the first polarized light beam 1001 entering the first sub-optical waveguide component 2011 is the same as the total internal reflection propagation direction of the second polarized light beam 1002 entering the second sub-optical waveguide component 2012, the angle between the transflective element in the first sub-optical waveguide component 2011 and the transflective element in the second sub-optical waveguide component 2012 can be no greater than 5 degrees. For example, the transflective elements in the two sub-optical waveguide components are parallel to facilitate the fabrication of the optical waveguide components.

[0133] For example, Figure 9 As shown, the angles between the transflective elements in the first optical waveguide sub-component 2011 and the transflective elements in the second optical waveguide sub-component 2012 and the first direction are both acute or obtuse. For example, the transflective elements in the first optical waveguide sub-component 2011 and the second optical waveguide sub-component 2012 are tilted in the same direction. The tilt direction here can refer to the tilt direction of the transflective elements relative to the light emitting surface. However, this is not limited to this. The tilt direction here can also refer to tilting to the left or right relative to the Y direction.

[0134] exist Figure 9 The direction indicated by the arrow in the X direction is the first direction (for example, when referring to the angle with the direction mentioned above, the first direction can be regarded as a vector), and the total internal reflection propagation direction of the first polarized light beam 1001 entering the first sub-optical waveguide element 2011 is the same as the total internal reflection propagation direction of the second polarized light beam 1002 entering the second sub-optical waveguide element 2012. When the total internal reflection propagation direction of each polarized light is the same as the first direction, the angle between each transflective element and the first direction is an acute angle; when the total internal reflection propagation direction of each polarized light is opposite to the first direction, the angle between each transflective element and the first direction is an obtuse angle.

[0135] For example, Figure 10 Schematic diagram of the partial structure of a backlight source in another example according to an embodiment of the present disclosure. Figure 10 The example shown is the same as Figure 9 The difference between the examples shown is that the positional relationship of the multiple sub-optical waveguide elements is different. Figure 10As shown, multiple sub-optical waveguide elements are arranged along a first direction. For example, multiple sub-optical waveguide elements do not overlap in a direction perpendicular to the display surface of the display panel, which can reduce the thickness of the backlight source and reduce the degree of weakening of the light intensity at the edge of the optical waveguide element by setting the length of each sub-optical waveguide element to be shorter. For example, multiple sub-optical waveguide elements do not overlap in a direction perpendicular to the display surface of the display panel, and can be exactly connected or at a certain distance, such as Figure 10 shown.

[0136] For example, the plurality of sub-optical waveguide elements may include a first sub-optical waveguide element 2011 and a second sub-optical waveguide element 2012 arranged along a first direction. The second polarized light beam 1002 transmitted by the polarization beam splitting element 310 enters the second sub-optical waveguide element 2012 through the second light coupling portion 232 in the second sub-optical waveguide element 2012. The reflected first polarized light beam 1001 enters the first sub-optical waveguide element 2011 through the first light coupling portion 231 in the first sub-optical waveguide element 2011 without passing through a reflective element. The first polarized light beam 1001 and the second polarized light beam 1002 pass through the transflective element arrays in their respective sub-waveguide elements and are output as collimated light beams, thereby achieving the effect of converting a normal light source into a uniform surface light source.

[0137] For example, if the total internal reflection propagation direction of light in the first optical waveguide sub-component 2011 is opposite to the total internal reflection propagation direction of light in the second optical waveguide sub-component 2012, the transflective element in the first optical waveguide sub-component 2011 and the transflective element in the second optical waveguide sub-component 2012 are not parallel. For example, one of the transflective elements may have an acute angle with the first direction, while the other may have an obtuse angle with the first direction, thereby achieving light outcoupling from the transflective element. For example, the transflective element in the first optical waveguide sub-component 2011 and the transflective element in the second optical waveguide sub-component 2012 may have different tilt directions.

[0138] For example, Figure 11 FIG. 1 is a schematic diagram of a partial structure of a backlight source in another example according to an embodiment of the present disclosure. Figure 11 As shown, the spectrometer 300 is configured to split the light emitted from the light source 100 to the optical waveguide into multiple light beams with different wavelengths. For example, the spectrometer 300 may include a spectrometer prism, a spectrometer grating, or other components that can separate light beams with different wavelengths.

[0139] For example, Figure 11As shown, the multiple sub-light beams include a first color light 1003 and a second color light 1004 with different wavelengths, and the multiple sub-optical waveguide elements 201 include a first sub-optical waveguide element 2011 and a second sub-optical waveguide element 2012. The first color light 1003 is configured to enter the first sub-optical waveguide element 2011 and be reflected out of the first sub-optical waveguide element 2011 by the transflective element array located in the first sub-optical waveguide element 2011. The second color light 1004 is configured to enter the second sub-optical waveguide element 2012 and be reflected out of the second sub-optical waveguide element 2012 by the transflective element array located in the second sub-optical waveguide element 2012.

[0140] The embodiment of the present disclosure facilitates the total reflection propagation control of light of different colors by allowing light of different colors to enter different sub-optical waveguide elements, thereby improving the utilization rate of light.

[0141] For example, the transflective element of the first sub-optical waveguide component 2011 is configured to have a greater reflectivity for the first color light 1003 than for the second color light 1004, and the transflective element of the second sub-optical waveguide component 2012 is configured to have a greater reflectivity for the second color light 1004 than for the first color light 1003. By regulating the reflectivity and transmittance of the transflective elements in different sub-optical waveguide components, the disclosed embodiments can improve the utilization rate of light incident on the corresponding sub-optical waveguide components.

[0142] For example, the first color light 1003 may be red light or green light, and the second color light 1004 may be blue light. The present disclosure is not limited thereto, and the first color light and the second color light may be interchangeable.

[0143] For example, Figure 12 FIG. 1 is a schematic diagram of a partial structure of a backlight source in another example according to an embodiment of the present disclosure. Figure 12 As shown, the plurality of sub-light beams further include a 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. Figure 12 As shown, the first color light 1003 and the third color light 1005 enter the first sub-optical waveguide component 2011, and the second color light 1004 enters the second sub-optical waveguide component 2012. The present disclosure is not limited thereto, and the third color light and the second color light may also enter the same sub-optical waveguide component.

[0144] In the embodiment of the present disclosure, by allowing two light rays of different colors to enter the same sub-optical waveguide component, the manufacturing cost of the optical waveguide component can be reduced, and the thickness of the backlight source can also be reduced.

[0145] For example, the first color light 1003 and the third color light 1005 can be red and green respectively, and the second color light 1004 can be blue. The present disclosure is not limited thereto, and the first color light and the third color light can also be green and blue respectively, and the second color light can be red.

[0146] In the embodiment of the present disclosure, two colors of light with similar wavelengths are introduced into the same sub-optical waveguide element, which can facilitate the adjustment of the transflective element array in the sub-optical waveguide element and reduce costs.

[0147] For example, Figure 13 Schematic diagram of the partial structure of a backlight source in another example according to an embodiment of the present disclosure. Figure 13 The example shown is the same as Figure 12 The difference of the example shown is that multiple beams of light of different colors are configured to enter multiple sub-optical waveguide elements one by one. Figure 13 As shown, the multiple sub-beams also include third color light 1005, and the multiple sub-optical waveguide elements 201 also include a third sub-optical waveguide element 2013. The third color light 1005 is configured to enter the third sub-optical waveguide element 2013 and be reflected out of the third sub-optical waveguide element 2013 by the array of transflective elements located in the third sub-optical waveguide element 2013. By allowing different colors of light to enter different sub-optical waveguide elements one by one, the disclosed embodiment can further improve light utilization.

[0148] For example, Figure 13 As shown, the transflective element of the first sub-optical waveguide component 2011 is configured to have a higher reflectivity for the first color light 1003 than for the second color light 1004 and the third color light 1005. The transflective element of the second sub-optical waveguide component 2012 is configured to have a higher reflectivity for the second color light 1004 than for the first color light 1003 and the third color light 1005. The transflective element of the third sub-optical waveguide component 2013 is configured to have a higher reflectivity for the third color light 1005 than for the first color light 1003 and the second color light 1004. By regulating the reflectivity and transmittance of the transflective elements in different sub-optical waveguide components, the disclosed embodiments can improve the utilization rate of light incident on the corresponding sub-optical waveguide components.

[0149] For example, Figure 13As shown, the refractive indices of the waveguide mediums of the first sub-waveguide element 2011, the second sub-waveguide element 2012, and the third sub-waveguide element 2013 can differ, and each is configured to adapt to the refractive index of the light entering the corresponding sub-waveguide element. For example, the first color light 1003, the second color light 1004, and the third color light 1005 are blue, red, and green, respectively. If these three light rays are coupled into the same optical waveguide element, the different wavelengths of light propagate through the same medium, which has different refractive indices for each light ray. Therefore, the total internal reflection angles of the three wavelengths differ (for example, the critical angle for total internal reflection of red light is greater than that of blue light). The angles of the transflective and reflective elements must also account for the three propagating angles, resulting in lower efficiency. To achieve similar total internal reflection angles for the three light rays, the media must be configured to have different refractive indices. Therefore, by separating the different light rays, each sub-waveguide element can select a medium and corresponding transflective and reflective element that maximizes the propagation of the corresponding light ray at the desired total internal reflection conditions, thereby improving light utilization.

[0150] For example, the embodiments of the present disclosure are not limited to the case where the multiple sub-beams are sub-light beams with different polarization directions or wavelengths. Each sub-beam in the multiple sub-beams may also be a sub-light beam with the same properties, that is, the spectroscopic element is only configured to divide a beam of light emitted by the light source into multiple sub-beams with the same properties, and the multiple sub-beams are configured to enter multiple sub-optical waveguide elements one by one. Compared to entering a beam of light emitted by the light source into one optical waveguide element, the embodiments of the present disclosure can improve the utilization rate of light and the uniformity of the outcoupled light by dividing a beam of light emitted by the light source into multiple beams of light, and respectively entering different sub-optical waveguide elements. When each sub-beam in the multiple sub-beams has the same properties, the multiple sub-optical waveguide elements may or may not overlap in a direction perpendicular to the display surface of the display panel.

[0151] For example, the optical waveguide element includes multiple sub-optical waveguide elements. Regardless of whether the multiple sub-optical waveguide elements are arranged in a direction parallel to the display surface of the display panel or arranged in a direction perpendicular to the display surface of the display panel, in at least one of the above-mentioned multiple sub-optical waveguide elements, multiple transflective elements are evenly arranged and the reflectivity gradually increases along the direction of total reflection propagation of light in the waveguide medium.

[0152] For example, the optical waveguide element includes multiple sub-optical waveguide elements. Regardless of whether the multiple sub-optical waveguide elements are arranged in a direction parallel to the display surface of the display panel or in a direction perpendicular to the display surface of the display panel, in at least one of the above-mentioned multiple sub-optical waveguide elements, the arrangement density of the multiple transflective elements gradually increases along the direction of total reflection propagation of light in the waveguide medium.

[0153] During their research, the inventors of this application also discovered that: A liquid crystal display device has two polarizers with different light transmission directions on either side of the liquid crystal layer, one of which is positioned between the liquid crystal layer and the backlight. This allows only light with a specific polarization state to pass through the polarizer between the liquid crystal layer and the backlight, enter the liquid crystal display panel, and be used to form an image. For example, when the backlight emits unpolarized light, only a maximum of 50% of the light emitted by the backlight can be used by the liquid crystal layer. The remaining light is wasted or absorbed by the liquid crystal layer to generate heat, resulting in a low light utilization rate.

[0154] Figure 14 This is a partial structural diagram of a backlight source provided in accordance with an example of another embodiment of the present disclosure. The backlight source in this embodiment may also be referred to as a light source device, which may be applied to a display device together with a display panel or used alone, and the present disclosure does not limit this. For example, the light source device in this embodiment may be disposed on the back side of a transmissive display panel or on the display side of a reflective display panel to provide light for the display panel. The light source device in this embodiment (e.g., backlight source) may be applied to any display device requiring a light source.

[0155] like Figure 14 As shown, the light source device includes: a light source unit 100, wherein 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; and an optical waveguide element 200, which includes an optical coupling unit 240. The light source unit 100 is configured such that the light emitted by the light source unit 100 propagates reflectively within the optical waveguide element 200 after entering the optical waveguide element 200. The optical coupling unit 240 is configured to couple out the light propagating reflectively within the optical waveguide element 200. The optical coupling unit 240 includes a first optical coupling unit 241 and a second optical coupling unit 242. The first optical coupling unit 241 is configured to couple out the first polarized light 100-1 that has entered the optical waveguide element 200. The light source device also includes a polarization conversion structure 400, which is configured to convert the second polarized light 100-2 that has entered the optical waveguide element 200 into the first polarized light 100-1. The second optical coupling unit 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 entering the optical waveguide element 200 into the first polarized light 100-1; or the second optical coupling unit 242 is configured to couple out the second polarized light 100-2 entering the optical 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.

[0156] like Figure 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.

[0157] For example, Figure 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.

[0158] 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. Figure 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.

[0159] 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.

[0160] For example, Figure 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 .

[0161] 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.

[0162] For example, the light source unit 100 in this embodiment can be connected to Figures 1A to 13 The light source unit 100 in the embodiment shown has the same features, which will not be described in detail here. Figures 1A to 13 The waveguide medium 210 in the illustrated embodiment has the same features, which will not be described again.

[0163] For example, in this embodiment, the light coupling portion may be provided or not provided. Figures 1A to 13 The light coupling portions provided in the illustrated embodiments have the same or similar features, which will not be described in detail here.

[0164] For example, the light emitted by the light source unit 100 may be unpolarized light, which includes a first polarized light beam 1001 and a second polarized light beam 1002 having different polarization directions. For example, the first polarized light beam 1001 and the second polarized light beam 1002 may be two linearly polarized lights with perpendicular polarization directions, such as S-polarized light and P-polarized light. The disclosed embodiments are not limited to this, and the first polarized light and the second polarized light may also be two circularly polarized lights or elliptically polarized lights with opposite rotation directions. For example, the disclosed embodiments are not limited to the light emitted by the light source unit including only two polarization states, but may also include three or more polarization states.

[0165] For example, the first polarized light beam 1001 emitted from the first light outcoupling unit 241 does not change its characteristics when it enters the predetermined area 40. For example, the converted first polarized light beam 1001′ has the same characteristics as the first polarized light beam 1001 in the light emitted by the light source unit 100, that is, it is polarized light with the same polarization state. For example, the second polarized light beam 1002 emitted from the second light outcoupling unit 242 has its polarization direction changed by the polarization conversion structure 400 when it enters the predetermined area 40.

[0166] For example, the embodiments of the present disclosure are not limited to the light from the light source portion entering the optical waveguide element being propagated by total reflection in the optical waveguide element. For example, the light emitted by the light source portion may also be transmitted in the transflective element in a non-total reflection manner, for example, it may be propagated along a straight line.

[0167] Figure 15 FIG. 1 is a schematic diagram of a partial structure of a backlight source according to an example of another embodiment of the present disclosure. Figure 15 As shown, the backlight further includes a beam splitter element 300 configured to perform beam splitting processing on the light emitted by the light source unit 100 and directed toward the optical waveguide element 200. For example, the beam splitter element 300 may be located between the light source unit 100 and the optical waveguide element 200, and configured to split the light emitted by the light source unit 100 toward the optical waveguide element 200 into a first polarized light beam 1001 and a second polarized light beam 1002.

[0168] For example, the light source unit 100 emits non-polarized light, and the spectrometer element 300 includes a polarization spectrometer element 310, which is 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; the spectrometer element 300 also includes a reflective element 320, which is configured to reflect one of the first polarization light and the second polarization light.

[0169] For example, the polarization splitting element 310 is configured to split the unpolarized light emitted from the light source unit 100 toward the optical waveguide element 200 into a first polarized light beam 1001 and a second polarized light beam 1002 before the light enters the optical waveguide element 200 .

[0170] For example, Figure 15 As 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 optical coupling unit 241. The first polarized light beam 1001 is configured to enter the first sub-element 2001 and be coupled out to the predetermined region 40 by the first optical coupling unit 241. That is, the first polarized light beam 1001 output by the first optical coupling unit 241 is directly output, such as collimated light. For example, the second polarized light beam 1002 is configured to enter the second sub-element 2002.

[0171] For example, Figure 15 As shown, the second sub-element 2002 includes a second light outcoupling portion 242, and the polarization conversion structure 400 is configured to convert the second polarized light coupled out of the second light outcoupling portion 242 into the first polarized light. The first sub-element 2001 includes a light-emitting surface, and the first sub-element 2001 and the second sub-element 2002 overlap in a direction perpendicular to the light-emitting surface, with the polarization conversion structure 400 located between the first sub-element 2001 and the second sub-element 2002; alternatively, the first sub-element 2001 and the second sub-element 2002 do not overlap in a direction perpendicular to the light-emitting surface.

[0172] For example, Figure 15 As shown, the second sub-element 2002 is provided with a second light outcoupling portion 242, and the polarization conversion structure 400 is provided on the light-emitting side of the second light outcoupling portion 242 to convert the second polarized light beam 1002 coupled out from the second light outcoupling portion 242 into a first polarized light beam 1001'. For example, Figure 15 The first sub-element and the second sub-element shown are both provided with an optical outcoupling portion, and can be used with Figure 9 The sub-optical waveguide elements may have the same structure or different structures.

[0173] For example, Figure 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.

[0174] For example, Figure 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. Figure 15 It is schematically shown that the first sub-element and the second sub-element completely overlap in the Y direction.

[0175] For example, Figure 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.

[0176] 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.

[0177] For example, Figure 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. Figure 9 The polarization splitting elements shown have the same features, which will not be described in detail here.

[0178] For example, Figure 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. Figure 9 The reflective elements shown have the same features, which will not be described again.

[0179] For example, Figure 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. Figure 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.

[0180] 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.

[0181] For example, Figure 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.

[0182] Figure 16 for Figure 15 An example of a backlight source is shown in FIG. Figure 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.

[0183] For example, Figure 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.

[0184] For example, Figure 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.

[0185] For example, Figure 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.

[0186] For example, Figure 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. Figure 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.

[0187] For example, Figure 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 .

[0188] The arrangement of the transflective elements in the embodiment of the present disclosure can be Figure 9 The arrangement of the transflective elements in the illustrated examples has the same features, which will not be described in detail here.

[0189] For example, Figure 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.

[0190] 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.

[0191] For example, Figure 17 A schematic diagram of the partial structure of a backlight source provided according to another example of another embodiment of the present disclosure. Figure 17 The example shown is the same as Figure 15 The examples shown differ in that Figure 17 The positional relationship between the first sub-element and the second sub-element is different. Figure 17 As shown, the first sub-element 2001 includes a light emitting surface, and the first sub-element 2001 and the second sub-element 2002 do not overlap in the direction perpendicular to the light emitting surface (i.e., the Y direction) (for example, they may be exactly connected, or there may be a certain distance between them). This can not only reduce the thickness of the backlight source, but also reduce the degree of weakening of the light intensity at the edge of the optical waveguide element by setting the length of each sub-element to be smaller.

[0192] For example, Figure 17 As shown, the first sub-element 2001 and the second sub-element 2002 are arranged along a first direction, and the light source unit 100 can be located between the first sub-element 2001 and the second sub-element 2002, but the present invention is not limited thereto. For example, when the light source unit 100 is located between the first sub-element 2001 and the second sub-element 2002, the total internal reflection propagation directions of the first polarized light beam 1001 and the second polarized light beam 1002 are opposite. In this case, the transflective element in the first sub-element 2001 and the transflective element in the second sub-element 2002 are not parallel. For example, one of the transflective elements may be at an acute angle to the first direction, while the other may be at an obtuse angle to the first direction, thereby achieving light outcoupling from the transflective element.

[0193] For example, Figure 18 A schematic diagram of the partial structure of a backlight source provided according to another example of another embodiment of the present disclosure. Figure 18 The example shown is the same as Figure 15 The difference between the examples shown is the position of the second light outcoupling section. Figure 18 As shown, the first light outcoupling unit 241 and the second light outcoupling unit 242 are both located in the first sub-element 2001. In this example, the light incident on the optical waveguide element is polarized light.

[0194] For example, Figure 18 As shown, the first sub-element 2001 includes a second light outcoupling portion 242, the first sub-element 2001 includes a light emitting surface, the first sub-element 2001 and the second sub-element 2002 overlap in a direction perpendicular to the light emitting surface, and the polarization conversion structure 400 is located on the light incident side of the second light outcoupling portion 242. The second polarized light entering the second sub-element 2002 is totally reflected and propagates in the second sub-element and is converted into the first polarized light by the polarization conversion structure 400. The first deflected light obtained by the conversion is then coupled out by the second light outcoupling portion 242.

[0195] For example, Figure 18 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.

[0196] 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 Figure 15-17 The examples shown may be the same or different. For example, the light splitting element 300 in this example may be the same as Figure 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 Figure 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 Figure 15 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.

[0197] For example, Figure 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.

[0198] 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.

[0199] For example, Figure 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 .

[0200] For example, Figure 18Although a gap is schematically shown between the first light outcoupling portion 241 and the second light outcoupling portion 242, the present invention is not limited thereto. Alternatively, the gap may be removed to prevent a dark region where no light is emitted from the two light outcoupling portions. For example, the first light outcoupling portion and the second light outcoupling portion may overlap to improve light uniformity.

[0201] For example, Figure 18 The schematic diagram shows 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 is not limited to this. 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 an integrated structure, the polarization conversion structure can be located inside the first sub-element and the second sub-element, or outside the first sub-element and the second sub-element. The polarization conversion structure can be located on the light incident side of the second optical coupling unit, that is, the second polarized light propagating in the second sub-element is converted into the first polarized light by the polarization conversion structure, and the first polarized light is coupled out by the second optical coupling unit.

[0202] For example, the second sub-element 2002 may include other optical coupling parts (for example, the second sub-element and the first sub-element are separate structures), or may not include an optical coupling part (for example, the first sub-element and the second sub-element are an integrated structure), and the second sub-element is mainly configured to allow the second polarized light to propagate therein by total reflection.

[0203] For example, Figure 18 The schematic diagram shows that a third light coupling portion 233 is provided on the light incident side of the second light coupling portion 242 in the first sub-element 2001. The third light coupling portion 233 may have the same features as the first light coupling portion and the second light coupling portion in the above embodiment, but is not limited thereto. The light incident side of the second light coupling portion 242 in the first sub-element 2001 may also not be provided with a light coupling portion.

[0204] For example, the second polarized light may be converted into the first polarized light after passing through the polarization conversion structure only once, for example, the polarization conversion structure may be a half-wave plate. Of course, the disclosed embodiments are not limited thereto, and the second polarized light may also be converted into the first polarized light after passing through the polarization conversion structure twice, for example, the polarization conversion structure may be a quarter-wave plate.

[0205] For example, Figure 18As shown, the polarization conversion structure 400 is arranged in the second sub-element 2002, and a reflective structure 500 is also provided in the second sub-element 2002, which is located on the side of the polarization conversion structure 400 away from the light source unit 100. The second polarized light beam 1002 that is totally reflected and propagates in the second sub-element 2002 is configured to pass through the polarization conversion structure 400 twice, and is reflected once by the reflective structure 500 before entering the first sub-element 2001.

[0206] Figure 19 for Figure 18 An example of a backlight source is shown in FIG. Figure 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 unpolarized light emitted by the light source unit 100 passes through the polarization beam splitting element 310 with polarization beam splitting function, transmitting the P-polarized light and reflecting the S-polarized light (and vice versa). The transmitted P-polarized light enters the second sub-element 2002 through the second light coupling portion 232, propagates through total reflection in the waveguide medium of the second sub-element 2002, and propagates to the reflective structure 500 at the end face. The reflected light no longer meets the total reflection condition and will leave the second sub-element 2002. The reflective structure 500 here can be regarded as the light coupling portion of the second sub-element 2002. At the same time, a polarization conversion structure 400 is also provided on the light-entering side of the reflective structure 500. When the P-polarized light is reflected, it first passes through the polarization conversion structure 400. The reflected light also passes through the polarization conversion structure 400 again before leaving the second sub-element 2002. That is, after the P-polarized light passes through the polarization conversion structure 400 twice, it will be converted into S-polarized light. The converted S-polarized light enters the waveguide medium of the first sub-element 2001 through the third entrance portion 233, undergoes total reflection, is transmitted to the second optical coupling portion 242, and is coupled out from the first sub-element 2001.

[0207] For example, Figure 19 As shown, both the first light outcoupling section 241 and the second light outcoupling section 242 include a transflective element array 220. Each transflective element 221 included in the transflective element array 220 forms an approximately equal angle with light incident on its surface. For example, the transflective element array 220 in the first light outcoupling section 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 section 242 includes a plurality of second transflective elements 2212 arranged along the first direction. Since the total internal reflection propagation direction of the first polarized light beam 1001 incident on the first optical outcoupling unit 241 is opposite to the total internal reflection propagation direction of the converted first polarized light beam 1001′ incident on the second optical outcoupling unit 242, the first transflective element 2211 and the second transflective element 2212 are not parallel, that is, the tilt directions of the two are different. For example, the angle between one of the first transflective element 2211 and the second transflective element 2212 and the first direction is an acute angle, and the angle between the other and the first direction is an obtuse angle.

[0208] For example, Figure 19 It is schematically shown that the first sub-element and the second sub-element are at least partially overlapped in the Y direction, but the present invention is not limited thereto. The first sub-element and the second sub-element may also not overlap in the Y direction.

[0209] For example, Figure 20 A schematic diagram of the partial structure of a backlight source provided in yet another example according to another embodiment of the present disclosure. Figure 20 The example shown is the same as Figure 14 The illustrated example is different in that the light emitted from the light source portion is unpolarized light when entering the optical waveguide element.

[0210] like Figure 20 As shown, the optical waveguide element 200 includes a first sub-element 2001 and a second sub-element 2002. The first sub-element 2001 includes the first light outcoupling portion 241, and the second sub-element 2002 includes the second light outcoupling portion 242. For example, Figure 20 The first sub-element and the second sub-element shown are both provided with an optical outcoupling portion, and can be used with Figure 9 The sub-optical waveguide elements may have the same structure or different structures.

[0211] like Figure 20 As shown, the light source unit 100 is configured so that the light it emits enters the first sub-element 2001, and the first polarized light in the light is coupled out by the first optical coupling unit 241, and the second polarized light in the light propagates in the first sub-element 2001 to the polarization conversion structure 400 to be converted into the 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 optical coupling unit 242 to be coupled out by the second optical coupling unit 242.

[0212] 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 the side of the first light coupling portion away from the light incident 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 incident side of the second light coupling portion.

[0213] like Figure 20As 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 optical outcoupling portion 241, and the second sub-element 2002 is provided with a second optical outcoupling portion 242. Unpolarized light emitted by the light source unit 100 is configured to enter the first sub-element 2001, and a first polarized light beam 1001 in the light is coupled out by the first optical outcoupling portion 241. The second polarized light beam 1002 in the light is configured to propagate within the first sub-element 2001 to the polarization conversion structure 400 to be converted into a first polarized light beam 1001′. After being converted by the polarization conversion structure 400, the first polarized light beam 1001′ is configured to propagate within the second sub-element 2002 to the second optical outcoupling portion 242 to be coupled out by the second optical outcoupling portion 242. The first optical coupling unit can not only couple out light, but also split the non-polarized light entering from the light source unit. Therefore, the embodiment of the present disclosure performs polarization splitting on the non-polarized light entering from the light source unit through the optical coupling unit located in the optical waveguide element, and the setting of the splitting device can be omitted to save the volume of the backlight source.

[0214] 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 Figure 15-17 The examples shown may be the same or different. For example, the waveguide medium in the optical waveguide element of this example may be the same as Figure 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 Figure 15 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.

[0215] For example, Figure 20 As shown, the first light coupling unit 241 can be a structure having a high reflectivity for the first polarized light beam 1001 and a high transmittance for the second polarized light beam 1002. For example, the first polarized light is S polarized light and the second polarized light is P polarized light. Figure 20 As shown, the unpolarized light emitted by the light source unit 100 is no longer split before entering the optical waveguide component 200, but directly enters the first sub-component 2001. At this time, the first optical coupling unit 240 is a component with a high reflectivity for S-polarized light and a high transmittance for P-polarized light. As the light propagates, the S-polarized light gradually leaves the first sub-component 2001; the P-polarized light continues to transmit, and after passing through the polarization conversion element 400, it is converted into S-polarized light, then enters the second sub-component 2002 for transmission, and is coupled out of the second sub-component 2002 through the second optical coupling unit 242.

[0216] For example, Figure 20As shown, first sub-element 2001 includes a light-emitting surface, and first sub-element 2001 and second sub-element 2002 at least partially overlap in a direction perpendicular to the light-emitting surface. However, this is not limiting. The first and second sub-element may also be arranged along the direction of total internal reflection propagation of light, such as in the X-direction. For example, the first and second sub-element may not overlap in a direction perpendicular to the light-emitting surface. The first light coupling portion in the first sub-element may couple out the first polarized light and transmit the second polarized light, while the second light coupling portion in the second sub-element may couple out the converted first polarized light.

[0217] Figure 21 for Figure 20 An example of a backlight source is shown in FIG. Figure 21 As shown, both the first light outcoupling section 241 and the second light outcoupling section 242 include a transflective element array 220. Each transflective element 221 included in the transflective element array 220 forms an approximately equal angle with light incident on its surface. For example, the transflective element array 220 in the first light outcoupling section 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 section 242 includes a plurality of second transflective elements 2212 arranged along the first direction. Since the total internal reflection propagation direction of the first polarized light beam 1001 incident on the first optical outcoupling unit 241 is opposite to the total internal reflection propagation direction of the converted first polarized light beam 1001′ incident on the second optical outcoupling unit 242, the first transflective element 2211 and the second transflective element 2212 are not parallel, that is, the tilt directions of the two are different. For example, the angle between one of the first transflective element 2211 and the second transflective element 2212 and the first direction is an acute angle, and the angle between the other and the first direction is an obtuse angle.

[0218] The embodiments of the present disclosure are not limited thereto. When the first sub-element and the second sub-element are arranged along the X-direction, the total internal reflection propagation direction of the first polarized light incident on the first optical outcoupling portion is the same as the total internal reflection propagation direction of the converted first polarized light incident on the second optical outcoupling portion. In this case, the first transflective element and the second transflective element may be substantially parallel, that is, the inclination directions of the two are the same. For example, the angles between the first transflective element and the second transflective element and the first direction are both acute angles or obtuse angles.

[0219] For example, the first transflective element 2211 may be an element having a high reflectivity for the first polarized light beam 1001 and a high transmittance for the second polarized light beam 1002, thereby achieving splitting of unpolarized light. For example, the second transflective element 2212 may be a transflective element without polarization selection characteristics or an element having a high reflectivity for the first polarized light, and the present disclosure is not limited thereto.

[0220] For example, Figure 21As shown, the light emitted by the light source unit 100 is configured to propagate through total reflection in at least one of the first sub-element 2001 and the second sub-element 2002. For example, Figure 21 The schematic diagram shows that the light is totally reflected and propagated in both the first sub-element 2001 and the second sub-element 2002, but the present invention is not limited thereto. The light from the light source portion entering the first sub-element may also be transmitted in the first sub-element in a non-total internal reflection manner, such as directly propagating along a straight line and being output in sequence through the transflective effect of the transflective elements.

[0221] For example, the polarization conversion structure 400 can be disposed between the first sub-element 2001 and the second sub-element 2002. For example, the polarization conversion structure 400 can also be disposed in the first sub-element 2001 and located on a side of the first light outcoupling unit 241 away from the light source unit 100. For example, the polarization conversion structure 400 can also be disposed in the second sub-element 2002 and located on the light incident side of the second light outcoupling unit 242.

[0222] For example, Figure 21 The schematic diagram shows that the first and second sub-elements form an integrated structure, and the polarization conversion structure is located within the integrated structure, located on the light-emitting side of the first optical outcoupling unit and the light-entering side of the second optical outcoupling unit. The disclosed embodiments are not limited to this, and the polarization conversion structure may also be located outside the first and second sub-elements, such as on the light-emitting side of the first optical outcoupling unit and the light-entering side of the second optical outcoupling unit.

[0223] For example, Figure 21 As shown, the optical waveguide element 200 further includes a reflective structure 500 located on the light incident side of the polarization conversion structure 400 . The reflective structure 500 is configured to change the propagation direction of the second polarized light beam 1002 so as to make it incident on the polarization conversion structure 400 .

[0224] For example, the polarization conversion structure 400 may be a 1 / 2 wave plate. Figures 18 and 19 The polarization conversion structures in the illustrated examples are the same and will not be described again here.

[0225] Compared with the solution in which all the light emitted by the light source is transmitted and output through the same waveguide medium, the embodiment of the present disclosure adopts a solution in which the light emitted by the light source is divided into different polarization states and then separately transmitted and output through waveguides, which can further improve the brightness uniformity of the output light.

[0226] For example, Figure 22 FIG. 1 is a schematic diagram of a partial structure of a backlight source according to an example of another embodiment of the present disclosure. Figure 22As shown, the backlight includes a light source unit 100 and a light guide plate 2000. The light guide plate 2000 includes a light homogenizer 250 and a light guide element 200. The light guide element 200 includes a light exit surface. The light homogenizer 250 and the light guide element 200 are arranged in a direction parallel to the light exit surface. The light source unit 100 is configured so that light emitted by it undergoes multiple total reflections within the light homogenizer 250 before entering the light guide element 200 and exiting from the light exit surface of the light guide element 200.

[0227] For example, the number of multiple total reflections is not less than 5. For example, the number of multiple total reflections can be 5 to 20. For example, the number of multiple total reflections can be 6 to 12. For example, the number of multiple total reflections can be 6 to 8.

[0228] For example, the light homogenizer 250 includes a light input end and a light output end, which are arranged along the extension direction of the light output surface. The thickness of the light homogenizer 250 in a direction perpendicular to the light output surface is no greater than the thickness of the optical waveguide element 200 in the arrangement direction. Thus, by setting a smaller thickness for the light homogenizer, the number of total reflections of the totally reflected light within the light homogenizer can be increased.

[0229] For example, the optical waveguide element 200 includes a waveguide medium 210 and an optical coupling unit 240. The optical waveguide element 200 also includes a light homogenizing unit 250. Light from the light source unit 100 passes through the light homogenizing unit 250 before reaching the light coupling unit 240. The light entering the optical waveguide element 200 is configured to undergo 8 to 11 total reflections in the light homogenizing unit 250.

[0230] For example, the refractive index of the light homogenizer 250 is greater than the refractive index of the waveguide medium 210 in the optical waveguide element 200. By adjusting the refractive index of the light homogenizer, the critical angle of total internal reflection of light propagating through the light homogenizer can be adjusted. When the critical angle of total internal reflection is smaller, the number of total internal reflections can be increased.

[0231] For example, the light waveguide plate 2000 is an integrated structure. For example, the light homogenizer 250 and the waveguide medium 210 are an integrated structure. For example, the light homogenizer 250 can be located between the light output unit 240 and the light source unit 100. By providing the light homogenizer on the light-incident side of the light output unit of the waveguide medium, the disclosed embodiments can improve the uniformity of the light before it is transmitted to the light output unit. In other words, the light is homogenized before being output, thereby obtaining a uniformly bright and dark surface light source.

[0232] The phrase "the light homogenizer and the waveguide medium are an integrated structure" may refer to the light homogenizer and the waveguide medium being a single structure formed from the same material through a single process, or may refer to the light homogenizer and the waveguide medium being connected together by a fixing method such as bonding. For example, the light homogenizer and the waveguide medium may be made of materials with the same refractive index or materials with different refractive indices, and this is not limited in the present embodiment.

[0233] For example, Figure 22 The light homogenizing part shown can also be set Figures 1A to 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 Figures 1A to 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 Figures 1A to 21 The waveguide medium in any of the examples shown has the same characteristics, which will not be described in detail here. Figures 1A to 21 The light source parts in any of the examples shown have the same features, which will not be described in detail here.

[0234] For example, Figure 22 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.

[0235] For example, Figure 23 for Figure 22 The cross-sectional structure diagram of the backlight source is shown in FIG. Figure 23 As shown, in this embodiment, the light coupling portion 230 may be provided or not provided. Figure 23 As shown, the light coupling portion 230 provided in this embodiment can be Figures 1A to 21 The light coupling portion provided in any of the examples shown has the same features, which will not be described in detail here.

[0236] For example, Figure 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.

[0237] For example, Figure 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.

[0238] For example, Figure 23As 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.

[0239] For example, Figure 22 and Figure 23 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.

[0240] For example, Figure 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. Figure 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.

[0241] For example, Figure 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 .

[0242] 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.

[0243] 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.

[0244] For example, Figure 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.

[0245] For example, Figure 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 .

[0246] For example, Figure 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 .

[0247] For example, Figure 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. Figure 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.

[0248] 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.

[0249] For example, Figure 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.

[0250] For example, Figure 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 .

[0251] 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.

[0252] For example, the dimming unit 271 can serve as both the light outcoupling unit of the light homogenizing unit 250 and the light incoupling unit of the waveguide medium, or it can serve only as the light outcoupling unit of the light homogenizing unit 250, or only as the light incoupling unit of the waveguide medium. The embodiments of the present disclosure do not limit this.

[0253] For example, Figure 24 As shown, the connecting portion 270 further includes a reflective surface 272 , and the reflective surface 272 is configured to reflect the light emitted from the light homogenizing portion 250 toward the waveguide medium 210 .

[0254] For example, Figure 24 As shown, the light entering the light homogenizing section 250 is transmitted along the total reflection path in the light homogenizing section 250 and is transmitted to the dimming section 271. The dimming section 271 will destroy the total reflection condition of the light, so the light will continue to be transmitted to the reflecting surface 272 and reflected. The reflected light is transmitted to the optical coupling section 340 (for example, a transflective element array), and then coupled out through the optical coupling section 340, for example, converted into collimated parallel light output.

[0255] For example, Figure 22-24 As shown, the embodiments of the present disclosure further provide a light source device, which includes a light guide plate 2000 and a light source unit 100. The light guide plate 2000 includes a light homogenizing unit 250 and a light guide element 200. The light guide element 250 includes a light exiting surface, and the light homogenizing unit 250 and the light guide element 200 are arranged in a direction perpendicular to the light exiting surface. The light source unit 100 is configured so that light emitted by it undergoes multiple total reflections within the light homogenizing unit 250 before entering the light guide element 200 and then exiting from the light exiting surface of the light guide element 200. This light source device can be the backlight source in the above-mentioned embodiment, and can be applied to a display device together with a display panel, but is not limited thereto and can also be combined with other structures and applied to other devices.

[0256] For example, the display panel provided in the embodiments of the present disclosure may 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 conjunction with the light provided by the backlight source. For example, the light provided by the backlight source is converted into image light after passing through the liquid crystal display panel (such as a liquid crystal screen). The embodiments of the present disclosure are not limited thereto, and the display panel may also be an electrowetting screen or a silicon-based liquid crystal display element, etc. Regardless of the type of display panel, it can be combined with the backlight provided in the embodiments of the present disclosure to form a display device with uniform light output and light weight.

[0257] For example, Figure 25 FIG. 1 is a partial structural diagram of a display device according to an example of another embodiment of the present disclosure. Figure 25As shown, the display device further includes a light diffusion element 30 located between the light waveguide element 200 and the display panel 10. The light diffusion element 30 is configured to diffuse the light emitted by the light waveguide element 200, that is, the light diffusion element 30 is configured to diffuse the light beam passing through the light diffusion element 20. The backlight source in the embodiment of the present disclosure can be Figures 1A to 24 The backlight shown in any of the examples.

[0258] For example, the light diffuser 30 may be disposed on the light-emitting side of the display panel 10 to diffuse the image light emitted from the display panel 10 . The light diffuser 30 may be disposed close to the display panel 10 to improve the imaging effect.

[0259] For example, Figure 25 The schematic diagram shows a single light diffuser element, but this is not limiting. Multiple elements can be provided, spaced apart from each other, to further enhance the light beam dispersion effect. The disclosed embodiment schematically shows the light diffuser element positioned on the back side of the display panel, but this is not limiting. The light diffuser element can also be positioned on the display surface of the display panel. For example, the light diffuser element can be attached to the display surface of the display panel.

[0260] For example, the light diffusing element 30 is configured to diffuse a light beam passing through the light diffusing element 30 without changing the optical axis of the light beam. The above-mentioned "optical axis" refers to the center line of the light beam.

[0261] For example, after an incident light beam passes through the light diffusing element 30, it is diffused into a light spot having a specific size and shape along the propagation direction and uniform energy distribution. The size and shape of the light spot can be precisely controlled by the specific microstructures designed on the surface of the beam diffusing structure 30. The specific shapes mentioned above may include, but are not limited to, linear, circular, elliptical, square, and rectangular.

[0262] For example, the light diffuser 30 may not distinguish between the front and back sides. For example, the propagation angle and spot size of the diffused light beam determine the brightness and visible area of ​​the final image. The smaller the diffusion angle, the higher the image brightness and the smaller the visible area; and vice versa.

[0263] For example, the light diffusion element 30 includes at least one of a diffractive optical element and a scattering optical element.

[0264] For example, the light diffusion element 30 can be a low-cost scattering optical element, such as a light homogenizer, a diffuser, etc. When the light beam passes through a scattering optical element such as a light homogenizer, it will be scattered and a small amount of diffraction will occur, but scattering plays a major role. After the light beam passes through the scattering optical element, a larger light spot will be formed.

[0265] For example, the light diffuser 30 can also be a diffractive optical element (DOE), such as a beam shaper, which allows for more precise control of the diffusion effect. For example, a diffractive optical element, by designing specific microstructures on its surface, expands the light beam through diffraction, resulting in a smaller spot size and controllable shape.

[0266] For example, Figure 26 FIG. 1 is a partial structural diagram of a display device according to another example of another embodiment of the present disclosure. Figure 26 As shown, the display device further includes: a light converging element 40, which is located between the light waveguide element 200 and the light diffusing element 30 and is configured to converge the light emitted from the light waveguide element 200 to the display panel 10. The backlight source in the embodiment of the present disclosure can be Figures 1A to 24 Backlight shown in any of the examples.

[0267] For example, Figure 26 As shown, the light converging element 40 is configured to control the direction of the collimated light emitted by the optical waveguide element 200, concentrating the light within a predetermined range. This further concentrates the light and improves light utilization. The predetermined range can be a point, such as the focus of a convex lens, or a smaller area. The purpose of providing the light converging element is to uniformly steer the collimated light output by the optical waveguide element within the predetermined range, thereby improving light utilization.

[0268] For example, the light converging element 40 may be a lens or a lens combination, for example, at least one lens, such as a convex lens, a Fresnel lens or a lens combination, Figure 26 A convex lens is used as an example for schematic illustration.

[0269] For example, Figure 26 As shown, the light converging element 40 can concentrate the collimated light output by the optical waveguide element 200 into a certain range, and the light diffusing element 30 can diffuse the concentrated light. The embodiment of the disclosure provides high light efficiency while also expanding the visible range through the cooperation of the light converging element and the light diffusing element.

[0270] For example, Figure 26 As shown, in the disclosed embodiment, the light converging element 40 can focus and direct nearly all light, ensuring that the light reaches the user's eyebox region 003. Therefore, the collimated light beam output by the optical waveguide element 200 is easily controllable, enabling convenient adjustment of the light's direction. For example, the area where the observer needs to view the image, i.e., the eyebox region 003, can be preset based on actual needs. This eyebox region 003 refers to the area where the observer's eyes are located and where the image displayed by the display device can be seen. For example, it can be a planar or three-dimensional area.

[0271] For example, Figure 26 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.

[0272] For example, Figure 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. Figure 27 The example shown is the same as Figure 26 The difference between the examples shown is the positional relationship between the light converging element and the light waveguide element. Figure 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.

[0273] For example, Figure 27 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.

[0274] 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.

[0275] 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.

[0276] For example, Figure 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.

[0277] 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.

[0278] For example, Figure 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.

[0279] 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.

[0280] 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.

[0281] For example, Figure 28 As shown, the light conversion device 50 is located on a side of the display panel 10 facing the optical waveguide element 200 . Figure 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.

[0282] 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.

[0283] For example, Figure 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. Figure 28It is schematically shown that the polarization direction of the second polarized light beam 102 is parallel to the polarization axis of the first polarization layer 10 - 1 , but it is not limited thereto. The polarization direction of the first polarized light may also be parallel to the polarization axis of the first polarization layer.

[0284] For example, Figure 28 As shown, the backlight source 20 emits unpolarized light, and the display panel 10 can use S-polarized light (second polarized beam 102). The beam splitter 51 reflects the S-polarized light and transmits the P-polarized light (first polarized beam 101). The direction-changing element 52 can also reflect the S-polarized light. The S-polarized light in the light emitted by the backlight source 20 is reflected by the beam splitter 51. The reflected S-polarized light is then reflected by the direction-changing element 52 before being emitted to the display panel 10. The P-polarized light in the light emitted by the backlight source 20 is then transmitted by the beam splitter 51 and converted to S-polarized light by the polarization conversion element 53. This converts all the unpolarized light emitted by the backlight source into S-polarized light that can be used by the display panel.

[0285] 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 characteristic of transmitting light of one polarization state and reflecting light of another polarization state. The beam splitting element can use the above-mentioned transmission and reflection characteristics to achieve beam splitting.

[0286] For example, the beam splitting element 51 may be a transflective film that transmits a portion of the light and reflects another portion of the light to achieve the beam splitting effect. For example, the transflective film may transmit the first polarized light beam 101 of the light emitted by the backlight source 20 and reflect the second polarized light beam 102 of the light emitted by the backlight source 20.

[0287] 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.

[0288] For example, the beam splitting element 51 may be formed by coating or attaching a film to a transparent substrate. For example, the beam splitting element 51 may be a transflective film coated or attached to a substrate, which has the characteristics of reflecting S-polarized light and transmitting P-polarized light, such as a reflective polarized brightness enhancement film (Dual Brightness Enhance Film, DBEF) or a prismatic brightness enhancement film (BEF). The embodiments of the present disclosure are not limited to this. For example, the beam splitting element may also be an integrated element.

[0289] For example, the direction-changing element 52 is configured to reflect the second polarized light beam 102 incident on the direction-changing element 52 toward the display panel 10 .

[0290] For example, the direction-changing element 52 may be a reflective element configured to reflect the second polarized light beam 102 emitted from the beam splitting element 51 toward the display panel 10. Since the polarization axis of the polarization 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 toward the display panel 10 can be directly utilized by the display panel 10.

[0291] For example, the redirecting element 52 can be a common reflector, such as a metal or glass reflector, or a reflective film coated or applied to a substrate with the property of reflecting S-polarized light. For example, the redirecting element 52 can also have transflective properties, similar to those of the transflective film included in the beam splitting element 51, namely, reflecting S-polarized light and transmitting P-polarized light. This is not a limitation of the present disclosure; it suffices that the redirecting element 52 reflect S-polarized light.

[0292] For example, the polarization conversion element 53 may be a phase retardation film, which rotates the polarization direction of the first polarized light beam 101 incident thereon by 90 degrees so that the light emitted from the phase retardation film toward the display panel 10 becomes the second polarized light beam 102 that can be used by the display panel 10. For example, the polarization conversion element 53 may be a half-wave plate.

[0293] For example, the polarization conversion element can be laminated to the beam splitting element. For example, a transparent substrate can be placed between the beam splitting element and the polarization conversion element, with the beam splitting element and the polarization conversion element respectively laminated to two opposing surfaces of the transparent substrate for convenient placement. The disclosed embodiments are not limited to this. For example, the beam splitting element can also be directly laminated to the surface of the polarization conversion element to achieve a thin and lightweight image source.

[0294] For example, Figure 28 As shown, the polarization conversion element 53 is located on a side of the beam splitting element 51 away from the direction changing element 50 .

[0295] For example, Figure 28 The schematic diagram shows that the beam splitting element and the redirecting element are nearly parallel, resulting in the output and recovered light being nearly parallel, collimated light. However, this is not limiting. If the beam splitting element and the redirecting element are not parallel, the output light can be diffuse or focused, which is suitable for certain special applications.

[0296] For example, Figure 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. Figure 29 The light conversion device shown is Figure 28 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. Figure 28 The features of the components shown are the same and will not be repeated here.

[0297] For example, Figure 30 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. Figure 30 The light conversion device shown is Figure 28 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. Figure 28 The features of the components shown are the same and will not be repeated here.

[0298] For example, Figure 31 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. Figure 31 The light conversion device shown is Figure 29 The difference of the light conversion device shown is that the light in this example passes through the polarization conversion element 53 twice, while Figure 29 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.

[0299] For example, Figure 31 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.

[0300] 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.

[0301] 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 Figure 28 The features of the corresponding elements shown are the same and will not be described again here.

[0302] Figure 32 The diagram is a partial structural diagram of a head-up display provided according to another embodiment of the present disclosure. Figure 32 The head-up display is schematically shown to include Figure 26 The display device shown, but not limited thereto, may also include Figure 25 ,or Figures 27 to 31 The embodiments of the present disclosure do not limit the display device shown in any example.

[0303] like Figure 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.

[0304] 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.

[0305] For example, Figure 32 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.

[0306] For example, Figure 32 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.

[0307] Figure 33 FIG. 1 is an exemplary block diagram of a traffic device according to another embodiment of the present disclosure. Figure 33As shown, the traffic device includes a head-up display provided by at least one embodiment of the present disclosure. The front window (eg, front windshield) of the traffic device is reused as a reflective imaging portion 60 of the head-up display.

[0308] For example, the transportation equipment can be various appropriate means of transportation, such as various types of land transportation equipment such as cars, or water transportation equipment such as ships, or air transportation equipment such as airplanes, with a front window set at the driving position and the image projected onto the front window through the on-board display system.

[0309] It should be noted that, for the sake of clarity, in the drawings used to describe the embodiments of the present disclosure, the thicknesses of layers or regions are enlarged or reduced, that is, these drawings are not drawn according to the actual scale.

[0310] Although the present disclosure has been described in detail above using general descriptions and specific embodiments, it will be apparent to those skilled in the art that modifications or improvements may be made based on the embodiments of the present disclosure. Therefore, such modifications or improvements, as long as they do not depart from the spirit of the present disclosure, are within the scope of protection claimed by the present disclosure.

[0311] There are a few points to note:

[0312] (1) The drawings of the embodiments of the present disclosure only involve structures related to the embodiments of the present disclosure, and other structures can refer to general designs.

[0313] (2) In the absence of conflict, features in the same embodiment and different embodiments of the present disclosure may be combined with each other.

[0314] The foregoing description is merely an exemplary embodiment of the present disclosure and is not intended to limit the scope of protection of the present disclosure. The scope of protection of the present disclosure is determined by the appended claims.

Claims

1. A light source device, comprising: a light source unit, wherein the light emitted by the light source unit includes a first polarized light and a second polarized light having different polarization states; An optical waveguide component including an optical coupling portion, The optical outcoupling portion includes a first optical outcoupling portion and a second optical outcoupling portion, and the first optical outcoupling portion is configured to couple out the first polarized light entering the optical waveguide element; The light source device further includes a polarization conversion structure configured to convert the second polarized light entering the optical waveguide element into the first polarized light. The second light outcoupling unit is configured to: after the polarization conversion structure converts the second polarized light entering the optical waveguide element into the first polarized light, couple the converted first polarized light out; or the second light outcoupling unit is configured to: couple the second polarized light entering the optical waveguide element out 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; The optical waveguide element further includes a waveguide medium, the light source unit is configured to cause the light emitted by it to enter the waveguide medium and propagate through total reflection in the waveguide medium, and the light coupling unit is configured to couple the light propagating through total reflection in the waveguide medium to a predetermined area; The light source device further includes: a spectroscopic element configured to perform spectroscopic processing on the light emitted by the light source unit and directed toward the optical waveguide element; wherein the optical waveguide element includes a plurality of sub-elements, the plurality of sub-elements including a first sub-element and a second sub-element, the first sub-element including a first optical coupling portion, the first polarized light subjected to the spectroscopic processing is coupled out by the first optical coupling portion after entering the first sub-element; the second polarized light subjected to the spectroscopic processing enters the second sub-element; the first sub-element includes a second optical coupling portion, the first sub-element includes a light emitting surface, the first sub-element and the second sub-element overlap in a direction perpendicular to the light emitting surface, the polarization conversion structure is located on a light incident side of the second optical coupling portion, the second polarized light entering the second sub-element is totally reflected and propagated in the second sub-element and is converted into first polarized light by the polarization conversion structure, and the converted first polarized light is coupled out by the second optical coupling portion; or The optical waveguide element includes a first sub-element and a second sub-element, the first sub-element includes the first optical outcoupling section, and the second sub-element includes the second optical outcoupling section; the light source section is configured so that the light it emits enters the first sub-element, and the first polarized light in the light is coupled out by the first optical outcoupling section, and the second polarized light in the light propagates in the first sub-element to the polarization conversion structure to be converted into the first polarized light; the first polarized light obtained after conversion by the polarization conversion structure propagates in the second sub-element to the second optical outcoupling section to be coupled out by the second optical outcoupling section.

2. The light source device according to claim 1, 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.

3. The light source device according to claim 1, wherein The second sub-element is provided with a reflective structure, and the second polarized light propagating through total internal reflection in the second sub-element enters the first sub-element after being converted by the polarization conversion structure and reflected by the reflective structure. The polarization conversion structure is disposed in the optical waveguide component, or is disposed outside the optical waveguide component. The light source device according to claim 1 , wherein: The light source portion is configured to transmit light emitted therefrom by being totally reflected in at least one of the first sub-element and the second sub-element. The light source device according to claim 1 , wherein: The first sub-element includes a light emitting surface, and the first sub-element and the second sub-element overlap in a direction perpendicular to the light emitting surface. The light source device according to claim 1 , wherein: 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 outcoupling portion away from a light incident 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 incident side of the second light outcoupling portion.

7. The light source device according to any one of claims 1 to 6, wherein: The light outcoupling unit includes a transflective element array, wherein each transflective element of the transflective element array is configured to reflect a portion of light propagating to the transflective element out of the optical waveguide element and transmit another portion of the light; The optical waveguide element includes a light emitting surface, and 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°.

8. The light source device according to claim 7, wherein: The transflective element array in the first light outcoupling portion includes a plurality of first transflective elements arranged along the extension direction of the light emitting surface, and the transflective element array in the second light outcoupling portion includes a plurality of second transflective elements arranged along the extension direction. The angle between the first polarized light transmitted to the first transflective element and the first transflective element is a third angle, the angle between the second polarized light transmitted to the second transflective element and the second transflective element is a fourth angle, and the difference between the third angle and the fourth angle is not greater than 10 degrees.

9. The light source device according to claim 8, wherein: The tilt direction of the first transflective element and the tilt direction of the second transflective element are the same as or different from each other.

10. The light source device according to claim 8, wherein The first transflective element is a transflective element having 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. The light source device according to claim 10 , 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.

12. A display device comprising: Display panel; The light source device according to any one of claims 1 to 11 is configured to provide backlight to the display panel.

13. The display device according to claim 12, further comprising: At least one light diffusion element is located on at least one of the display surface side 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 light waveguide element.

14. The display device according to claim 13, 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.

15. A head-up display comprising: The display device according to any one of claims 12 to 14; 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.

16. A traffic device comprising the head-up display according to claim 15.

17. The transportation device according to claim 16, wherein: The reflective imaging portion includes a windshield of the traffic equipment.

Images