CN218455809U

CN218455809U - Display device, head-up display and traffic equipment

Info

Publication number: CN218455809U
Application number: CN202220238785.6U
Authority: CN
Inventors: 吴慧军; 方涛; 徐俊峰
Original assignee: Futurus Technology Co Ltd
Current assignee: Futurus Technology Co Ltd
Priority date: 2022-01-28
Filing date: 2022-01-28
Publication date: 2023-02-07
Anticipated expiration: 2032-01-28

Abstract

The embodiment of the disclosure provides a display device, a head-up display and traffic equipment. The display device comprises a display panel and a backlight source. The backlight source comprises a light source part and a light conduction element, light incident to the light conduction element is sequentially transmitted to a plurality of light couplers of a light coupler array of the light conduction element, one part of the light transmitted to each light coupler of the light coupler array is reflected by the light couplers to penetrate through the display panel after being reflected out of a light emitting area of the light conduction element, and the other part of the light is transmitted through the light couplers to continue to be transmitted in the light conduction element. The last light outcoupling element in the direction of sequential propagation of light comprises a reflective film comprising a selectively reflective film and/or a non-selectively reflective film; and/or the chief ray of the light transmitted through the light outcoupling element is along the arrangement direction of the partial light outcoupling elements. By providing the light-transmitting member in the backlight, the display effect and the portability of the display device can be improved.

Description

Display device, head-up display and traffic equipment

Technical Field

The present disclosure relates to a display device, a head-up display, and a transportation apparatus.

Background

At present, users have increasingly demanded display devices including backlights, and have made more demands on the display effects and the portability of the display devices, and the backlights in the display devices have a certain influence on the display effects and the portability of the display devices.

Disclosure of Invention

At least one embodiment of the present disclosure provides a light source device, a display device, a head-up display, and a transportation apparatus.

In a first aspect, at least one embodiment of the present disclosure provides a light source device including a light source part and a light conduction member. The light emitted by the light source part comprises first polarized light and second polarized light with different polarization states; the light conducting element comprises a plurality of light out-coupling portions. The light source part is configured to make the light emitted by the light source part propagate in the light conduction element after entering the light conduction element, and the plurality of light out-coupling parts are configured to out-couple the light propagating in the light conduction element; the plurality of light out-coupling portions comprises a first light out-coupling portion and a second light out-coupling portion, the first light out-coupling portion being configured to couple out the first polarized light entering the light conducting element; the light source device further includes a polarization conversion structure configured to convert the second polarized light after entering the light conductive element into first polarized light, the second light out-coupling portion being configured to: after the polarization conversion structure converts the second polarized light entering the light conduction element into first polarized light, coupling the converted first polarized light out; or the second light outcoupling portion is configured to couple out the second polarized light entering the light conducting element to the polarization conversion structure, and the outcoupled second polarized light is converted into the first polarized light by the polarization conversion structure.

For example, in some embodiments of the first aspect of the present disclosure, the light source device is a backlight.

For example, in some embodiments of the first aspect of the present disclosure, the plurality of light out-coupling portions comprises a light out-coupling element array having a plurality of light out-coupling elements, the light out-coupling element array being configured to out-couple light rays in the light-conducting element and the out-coupled light rays exiting from a light exit region of the light-conducting element.

For example, in some embodiments of the first aspect of the present disclosure, the first light out-coupling part comprises a first light out-coupling element array comprising a plurality of first light out-coupling elements, and the second light out-coupling part comprises a second light out-coupling element array comprising a plurality of second light out-coupling elements.

In a second aspect, at least one embodiment of the present disclosure provides a display device, including: a display panel including a display surface and a back side opposite the display surface; and a backlight source positioned at a back side of the display panel.

For example, in some embodiments of the second aspect of the present disclosure, the backlight further includes a light source section, and light emitted from the light source section enters the light-transmitting member.

For example, in some embodiments of the second aspect of the present disclosure, the backlight is a light source device provided in the first aspect of the present disclosure. Alternatively, for example, in some embodiments of the second aspect of the present disclosure, the backlight comprises a light conducting element comprising a light exit area and an array of light outcoupling members configured to outcouple light rays in the light conducting element and the outcoupled light rays exit the light exit area of the light conducting element.

For example, in some embodiments of the first or second aspect of the present disclosure, the array of light outcouplers comprises a plurality of light outcouplers, light incident to the light conducting element is sequentially transmitted to the plurality of light outcouplers of the array of light outcouplers, a portion of light transmitted to each of at least some of the light outcouplers is reflected by the light outcouplers, and another portion of the light transmitted to each of at least some of the light outcouplers is transmitted through the light outcouplers.

For example, in some embodiments of the first or second aspects of the present disclosure, the portion of the light rays is reflected out of the light-conducting element by the light outcoupling member, and the other portion of the light rays continues to propagate in the light-conducting element after passing through the light outcoupling member; alternatively, a portion of the light rays is transmitted out of the light conducting element by the light outcoupling member and another portion of the light rays continues to propagate in the light conducting element after being reflected by the light outcoupling member.

For example, in some embodiments of the first or second aspect of the present disclosure, the last light outcoupling element in the direction of said sequential propagation of light rays comprises a reflective film comprising a selectively reflective film and/or a non-selectively reflective film.

For example, in some embodiments of the first or second aspects of the present disclosure, the selectively reflective film may comprise a polarizing reflective film. For example, the polarizing reflective film may include a polarizing transflective film and/or a polarizing absorbing film.

For example, in some embodiments of the first or second aspects of the present disclosure, the selective reflective film further comprises a wavelength selective reflective film.

For example, in some embodiments of the first or second aspects of the present disclosure, the plurality of light outcoupling members are gas between; or, a transparent optical medium is arranged among the light outcoupling members.

For example, in some embodiments of the first or second aspect of the present disclosure, reflecting the reflective film causes the last light out-coupling element to have the largest reflectivity among the plurality of light out-coupling elements; and/or the reflective film substantially totally reflects all light rays incident thereon or all selected light rays; and/or the reflecting film is a plated reflecting film or a reflecting film arranged in a sticking way or a reflecting film arranged independently; and/or, in case the last light out-coupling member comprises the reflective film, a chief ray of a light ray transmitted through the light out-coupling member intersects with an extending direction of a light emitting area of the light conductive element.

For example, in some embodiments of the first or second aspect of the present disclosure, the backlight source comprises a light-conducting plate comprising a light uniformizing section and the light-conducting element, light incident to the light uniformizing section entering the light-conducting element after being homogenized by the light uniformizing section; and/or the source light line of the backlight source comprises a component of first polarized light and a component of second polarized light, the polarization states of the first polarized light and the second polarized light are different, and the emergent light emitted from the light-emitting side of the backlight source is polarized light and comprises one of the first polarized light and the second polarized light; and/or the display device further comprises a light converging element and a light diffusing element, and the light conducting element, the light converging element, the light diffusing element and the display panel are arranged in sequence.

For example, in some embodiments of the first or second aspects of the present disclosure, light rays incident to the even portion enter the light-conducting element after multiple reflections within the even portion; the multiple reflection comprises at least one total reflection and/or at least one non-total reflection type reflection, and/or the light conduction plate is of an integrated structure.

For example, in some embodiments of the first or second aspect of the present disclosure, the backlight further includes a polarization splitting element configured to split the source light incident to the polarization splitting element into the first polarized light and the second polarized light, and a polarization conversion element configured to convert one of the first polarized light and the second polarized light into the other, the display panel being configured to generate image light using one of the first polarized light and the second polarized light. Polarized light obtained after the polarization conversion element converts one of the first polarized light and the second polarized light into the other is incident to the light conduction element; alternatively, one of the first polarized light and the second polarized light is converted into the other by the polarization conversion element after entering the light conduction element.

For example, in some embodiments of the first aspect or the second aspect of the present disclosure, the backlight further includes a reflective element configured to reflect the first polarized light or the second polarized light obtained after the light splitting process by the polarization light splitting element, wherein the polarized light reflected by the reflective element is incident on the optical waveguide element, or one of the first polarized light and the second polarized light is reflected by the reflective element after entering the light conducting element, and then is converted into the other of the first polarized light and the second polarized light by the polarization conversion element; one of the first polarized light and the second polarized light obtained by the spectral processing is reflected by the reflection element and then converted by the polarization conversion element, or is reflected by the reflection element after being first converted by the polarization conversion element and then is second converted by the polarization conversion element.

For example, in some embodiments of the first or second aspect of the present disclosure, the light-transmitting element includes a plurality of sub light-transmitting elements, the plurality of sub light-transmitting elements includes a first sub light-transmitting element and a second sub light-transmitting element connected to or spaced apart from each other, the first sub light-transmitting element and the second sub light-transmitting element are stacked in an arrangement direction of the backlight source and the display panel or sequentially arranged in a direction perpendicular to the arrangement direction of the backlight source and the display panel, and the polarization splitting element splits the first polarized light and the second polarized light obtained by the light splitting process and makes the first polarized light and the second polarized light incident on different sub light-transmitting elements; in a case where the first sub light-transmitting member and the second sub light-transmitting member are stacked in the arrangement direction of the backlight and the display panel, both the first sub light-transmitting member and the second sub light-transmitting member, into which the first polarized light and the second polarized light respectively enter, include the light outcoupling members arranged in sequence or one of them does not include the light outcoupling members arranged in sequence.

For example, in some embodiments of the first or second aspect of the present disclosure, in a case where the first sub light conduction element and the second sub light conduction element are arranged in a stacked manner, wherein a first light emitting region of the first sub light conduction element and a second light emitting region of the second sub light conduction element overlap, and light emitted from one of the first light emitting region and the second light emitting region passes through the polarization conversion element and then propagates to the other of the first light emitting region and the second light emitting region; or, the second sub optical conduction element includes a light conduction region and a second light exit region that are sequentially arranged along an extending direction of the second sub optical conduction element, polarized light in the second sub optical conduction element is reflected and propagated by total reflection and/or non-total reflection in the light conduction region and propagated to the second light exit region and then propagated to the first sub optical conduction element, and the light conduction region of the second sub optical waveguide element overlaps with the first light exit region of the first sub optical waveguide element.

For example, in some embodiments of the first or second aspect of the present disclosure, the backlight source further includes a light splitting element configured to split light incident to the light splitting element into a plurality of sub-beams, which respectively enter the plurality of sub-light transmitting elements included in the light transmitting element. The plurality of sub light conduction elements are arranged in an overlapped mode in a direction perpendicular to the display surface of the display panel, and/or the plurality of sub light conduction elements are arranged in a direction parallel to the display surface; the light splitting element is configured to split the source light incident to the light splitting element to obtain different characteristic light, and the different characteristic light is incident to different sub light conduction elements; the first characteristic light and the second characteristic light are respectively first polarized light and second polarized light with different polarization states, or the first characteristic light and the second characteristic light are respectively first color light and second color light with different wavelength distributions.

For example, in some embodiments of the first or second aspect of the present disclosure, after entering the light-conducting element, the light incident on the light-conducting element undergoes multiple total reflections at the light exit surface of the light-conducting element and propagates to the light outcouplers of the light outcoupler array in sequence, a part of the light propagating to each light outcoupler of the light outcoupler array is reflected by the light outcoupler out of the light exit surface of the light-conducting element and then passes through the display panel, and another part of the light propagating to each light outcoupler of the light outcoupler array continues to propagate in the light-conducting element after passing through the light outcoupler.

In a third aspect, at least one embodiment of the present disclosure provides a head up display, including: the light source device provided by any embodiment of the present disclosure or the display device including the light source device or the display device provided by any embodiment of the present disclosure.

For example, in some embodiments of the present disclosure, the head-up display further includes a reflective imaging portion located on a light-emitting side of the display device and configured to reflect light emitted from the display device and propagate the reflected light to a viewing area of the head-up display.

In a fourth aspect, at least one embodiment of the present disclosure provides a transportation device, including the light source device or the display device or the head-up display provided in any embodiment of the present disclosure.

For example, in some embodiments of the first or second aspect of the present disclosure, the light-conducting element further includes a waveguide medium into which the light emitted from the light source portion enters and propagates by total reflection in the waveguide medium.

For example, in some embodiments of the first or second aspect of the present disclosure, all or part of the light propagating to the last light out-coupling element is reflected out of the light exit area of the light guiding element by the last light out-coupling element before being transmitted through the display panel.

For example, in some embodiments of the first or second aspect of the present disclosure, an included angle between the light outcoupling member and the light outcoupling region is a first included angle, and a sum of the first included angle and a critical angle for total reflection of the light is in a range of 60 ° to 120 °.

For example, in some embodiments of the first or second aspect of the present disclosure, the light out-coupling comprises a light out-coupling.

For example, in some embodiments of the first or second aspects of the present disclosure, the light-conducting element comprises a plurality of sub light-conducting elements, the light out-coupler array comprises a plurality of sub light out-coupler arrays respectively located in the plurality of sub light-conducting elements; the backlight source further comprises a light splitting element configured to split light incident to the light splitting element into a plurality of sub-beams, the plurality of sub-beams enter the plurality of sub-light-conducting elements respectively, and each sub-beam entering each sub-light-conducting element is reflected out of the light emitting area of the light-conducting element by the sub-light-out-coupling element array located in each sub-light-conducting element.

For example, in some embodiments of the first or second aspect of the present disclosure, the plurality of sub light-conducting elements are arranged to overlap in a direction perpendicular to the display surface of the display panel, and/or the plurality of sub light-conducting elements are arranged in a direction parallel to the display surface; the plurality of sub light-transmitting elements includes a first sub light-transmitting element and a second sub light-transmitting element.

For example, in some embodiments of the first or second aspect of the present disclosure, the light incident to the light-transmitting element includes first characteristic light and second characteristic light having different characteristics, and the light-splitting element is configured to perform light-splitting processing on the light incident to the light-splitting element, cause the first characteristic light obtained by the light-splitting processing to be incident to the first sub light-transmitting element, and cause the second characteristic light obtained by the light-splitting processing to be incident to the second sub light-transmitting element.

For example, in some embodiments of the first or second aspects of the present disclosure, the first and second characteristic light are first and second polarized light, respectively, of different polarization states; alternatively, the first characteristic light and the second characteristic light may be first color light and second color light having different wavelength distributions, respectively.

For example, in some embodiments of the first or second aspect of the present disclosure, the plurality of sub-beams resulting from the splitting of the light rays comprises the first color light, the second color light, and a third color light configured to enter one of the first and second sub-light-conducting elements; alternatively, the plurality of sub-beams of light comprises the first color light, the second color light, and a third color light, the plurality of sub-light transmissive elements further comprising a third sub-light transmissive element, the third color light configured to enter the third sub-light transmissive element and be reflected off the third sub-light transmissive element by the array of light outcouplers located in the third sub-light transmissive element.

For example, in some embodiments of the first or second aspects of the present disclosure, the reflectivity of the light out-coupling member in the first sub light-conducting element for the first characteristic light is greater than the reflectivity of the light out-coupling member in the second sub light-conducting element for the second characteristic light, which is greater than the reflectivity of the light out-coupling member in the first sub light-conducting element for the first characteristic light.

For example, in some embodiments of the first or second aspect of the present disclosure, the light splitting element comprises a polarization light splitting element configured to have a reflectivity for one of the first and second polarized lights that is greater than its reflectivity for the other; and/or the polarization splitting element is configured to have a transmittance for one of the first polarized light and the second polarized light greater than its transmittance for the other.

For example, in some embodiments of the first or second aspect of the present disclosure, the light splitting element comprises a polarizing light splitting element configured to reflect one of the first polarized light and the second polarized light and transmit the other of the first polarized light and the second polarized light.

For example, in some embodiments of the first or second aspects of the present disclosure, the light splitting element further comprises a reflective element configured to reflect one of the first and second polarized light.

For example, in some embodiments of the first or second aspect of the present disclosure, the reflectivity of the light outcoupling elements arranged in sequence along the extending direction of the light outcoupling region in the light outcoupling element array gradually increases or gradually increases regionally in the propagation direction of the light; and/or the arrangement density of the light outcoupling elements arranged in sequence in the extending direction of the light outcoupling region in the light outcoupling element array gradually increases or gradually increases regionally.

For example, in some embodiments of the first or second aspects of the present disclosure, at least one light out-coupling element of the array of light out-coupling elements comprises a light-transmissive film, light entering the light-conducting element comprising first and second light rays of different characteristics, the light-transmissive film being configured to have a reflectivity for the first light ray that is greater than a reflectivity for the second light ray, and a transmissivity for the second light ray that is greater than a transmissivity for the first light ray.

For example, in some embodiments of the first or second aspect of the present disclosure, the array of light out-coupling members comprises a first set of light out-coupling members and a second set of light out-coupling members arranged along an extension direction of the light out-coupling area, each set of light out-coupling members comprising light out-coupling members arranged along an extension direction of the light out-coupling area, an oblique direction of the light out-coupling members of the first set of light out-coupling members with respect to the light out-coupling area being non-parallel to an oblique direction of the light out-coupling members of the second set of light out-coupling members with respect to the light out-coupling area.

For example, in some embodiments of the first or second aspect of the present disclosure, the backlight further includes a light source section including a first light source section and a second light source section, the first light source section and the second light source section being respectively located at both sides of the light out-coupling member array in the extending direction of the light out-coupling region, the first light out-coupling member group is configured to reflect the light emitted by the first light source section entering the light-conducting element out of the light-conducting element, and the second light out-coupling member group is configured to reflect the light emitted by the second light source section entering the light-conducting element out of the light-conducting element; or the light source unit is located between the first light out-coupling group and the second light out-coupling group in the extending direction of the light exit region.

For example, in some embodiments of the first or second aspect of the present disclosure, the backlight further includes a light source section, at least some of the light out-coupling members included in the light out-coupling member array are sequentially arranged along a first direction and extend along a second direction intersecting the first direction, and the light source section includes a plurality of sub light sources arranged along the second direction, and the plurality of sub light sources are configured to emit light entering the at least some of the light out-coupling members.

For example, in some embodiments of the first or second aspect of the present disclosure, the light out-coupling element array includes at least some of the light out-coupling elements arranged in sequence along a first direction and extending along a second direction intersecting the first direction, the display device further includes a plurality of beam expanding portions arranged along the second direction, the plurality of beam expanding portions are configured to expand the light emitted by the sub-light sources along the second direction, and the expanded light is configured to be transmitted to the light out-coupling element array.

For example, in some embodiments of the first or second aspect of the present disclosure, the backlight further includes a light source section that emits light including first polarized light and second polarized light having different polarization states, and the display panel is configured to generate image light using one of the first polarized light and the second polarized light.

For example, in some embodiments of the first or second aspect of the present disclosure, the display device further includes a light conversion device including a beam splitting element and a polarization conversion element, the beam splitting element being located on a side of the display panel facing the light conduction element and configured to split light incident to the beam splitting element into first and second polarized light beams having different polarization states, the polarization conversion element being configured to convert a polarized light beam of the first and second polarized light beams that cannot be utilized by the display panel into a polarized light beam that can be utilized by the display panel before reaching the display panel.

For example, in some embodiments of the first or second aspect of the present disclosure, the light conversion device is configured to recycle light emitted by the light source part and send the recycled light to the light conducting element, and/or recycle light emitted by the light conducting element and send the recycled light to the display panel.

For example, in an embodiment of the second aspect of the present disclosure, the display device further includes: at least one light diffusing element configured to diffuse light exiting at least one of the display panel and the light conductive element.

For example, in some embodiments of the second aspect of the present disclosure, the display device further comprises: a light converging element configured to converge the light emitted from the light conducting element and then direct the converged light to the at least one light diffusing element.

For example, in some embodiments of the second aspect of the present disclosure, the light converging element comprises at least one lens.

For example, in embodiments of the present disclosure, the light converging element is a unitary structure with the light conducting element.

For example, in some embodiments of the second aspect of the present disclosure, a transparent dielectric layer is disposed between the light converging element and the light conducting element, the transparent dielectric layer having a refractive index less than the refractive index of the light conducting element.

For example, in some embodiments of the first or second aspects of the present disclosure, the backlight is a side-entry backlight. For example, the light emitting region of the light guide member and the display surface of the display panel are stacked in a direction perpendicular to the display surface, and the light source portion included in the backlight is located on a side of the light guide member.

For example, in some embodiments of the first or second aspect of the present disclosure, the backlight source comprises a light-conducting plate comprising a light uniformizing portion and the light-conducting element, and light incident to the light uniformizing portion enters the light-conducting element after being homogenized by the light uniformizing portion.

For example, in some embodiments of the first or second aspect of the present disclosure, light incident to the even light section enters the light-conducting element after multiple reflections (e.g., total and/or non-total reflections) within the even light section.

For example, in some embodiments of the first or second aspect of the present disclosure, the light-conducting plate is a unitary structure.

For example, in an embodiment of the present disclosure, the reflective imaging section includes a windshield of the traffic device.

For example, in the first or second aspect embodiment of the present disclosure, in a case where the backlight includes a light-conducting plate and the light-conducting plate includes a light uniformizing portion and a light-conducting element, the light-conducting element includes a light exit region, and the light uniformizing portion and the light-conducting element are sequentially arranged in a direction perpendicular to the light exit region; the backlight source further includes a light source section configured to cause light emitted therefrom to enter the light-transmitting member after being totally reflected a plurality of times within the light uniformizing section and then to exit from the light exit region of the light-transmitting member.

For example, in some embodiments of the first or second aspect of the present disclosure, the light source section is configured to make light emitted therefrom propagate reflectively in the light-transmitting element after entering the light-transmitting element, and the light out-coupling section is configured to couple out light propagating reflectively in the light-transmitting element.

For example, in some embodiments of the first or second aspect of the present disclosure, a chief ray (also referred to as an optical axis) of a ray transmitted through the light out-coupling element intersects an alignment direction of the partial light out-coupling element; or, the chief ray of the light transmitted through the light-out-coupling member is along the arrangement direction of the partial light-out-coupling members.

In order to make the aforementioned and other objects, features and advantages of the present invention comprehensible, preferred embodiments accompanied with figures are described in detail below.

Drawings

To more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings of the embodiments will be briefly introduced below, and it is apparent that the drawings in the following description relate only to some embodiments of the present disclosure and are not limiting to the present disclosure.

Fig. 1A is a schematic partial cross-sectional structure diagram of a display device provided in accordance with an example of the embodiment of the present disclosure;

fig. 1B is a schematic partial cross-sectional structure diagram of a display device provided in accordance with an example of the embodiment of the present disclosure;

FIG. 2 is a schematic plan view of a backlight according to the example of FIG. 1A;

FIG. 3 is a schematic plan view of another backlight according to the example of FIG. 1A;

FIG. 4A is a schematic plan view of another backlight according to the example of FIG. 1A;

FIG. 4B is a schematic plan view of another backlight according to the example of FIG. 1A;

FIG. 5 is a schematic plan view of another backlight according to the example of FIG. 1A;

FIG. 6 is an example where light rays exiting the array of light outcoupling elements are not perpendicular to the major surface of the waveguide medium;

FIG. 7 is a schematic diagram of a partial structure of a backlight in another example according to an embodiment of the present disclosure;

FIG. 8 is a schematic diagram of a partial structure of a backlight in another example according to an embodiment of the present disclosure;

FIG. 9 is a schematic diagram of a partial structure of a backlight in another example according to an embodiment of the present disclosure;

FIG. 10 is a schematic diagram of a partial structure of a backlight in another example according to an embodiment of the present disclosure;

fig. 11 is a schematic view of a partial structure of a backlight in another example according to an embodiment of the present disclosure;

FIG. 12 is a schematic diagram of a partial structure of a backlight in another example according to an embodiment of the present disclosure;

FIG. 13 is a schematic diagram of a partial structure of a backlight in another example according to an embodiment of the present disclosure;

fig. 14 is a schematic view of a partial structure of a backlight provided according to an example of another embodiment of the present disclosure;

fig. 15 is a schematic view of a partial structure of a backlight provided according to an example of another embodiment of the present disclosure;

FIG. 16 is an exemplary illustration of the backlight of FIG. 15;

fig. 17 is a schematic view of a partial structure of a backlight provided in accordance with another example of another embodiment of the present disclosure;

fig. 18 is a schematic view of a partial structure of a backlight provided in accordance with another example of another embodiment of the present disclosure;

FIG. 19 is an exemplary illustration of the backlight of FIG. 18;

fig. 20 is a schematic view of a partial structure of a backlight according to another example of another embodiment of the present disclosure;

FIG. 21 is an exemplary illustration of the backlight of FIG. 20;

FIG. 22 is a schematic view of a partial structure of a backlight provided in accordance with an example of yet another embodiment of the present disclosure;

FIG. 23 is a cross-sectional view of the backlight of FIG. 22;

FIG. 24 is a schematic view of a portion of a backlight provided in accordance with another example of yet another embodiment of the present disclosure;

fig. 25 is a partial structural view of a display device provided according to an example of yet another embodiment of the present disclosure;

fig. 26 is a partial structural schematic view of a display device provided according to another example of yet another embodiment of the present disclosure;

fig. 27 is a partial structural schematic view of a display device provided according to another example of yet another embodiment of the present disclosure;

fig. 28 is a partial structural schematic view of a display device provided according to still another example of yet another embodiment of the present disclosure;

fig. 29 is a schematic view of a light conversion device in a display device provided according to still another example of yet another embodiment of the present disclosure;

fig. 30 is a schematic view of a light conversion device in a display device provided according to still another example of yet another embodiment of the present disclosure;

fig. 31 is a schematic view of a light conversion device in a display device provided according to still another example of yet another embodiment of the present disclosure;

fig. 32 is a schematic diagram illustrating a partial structure of a head-up display according to another embodiment of the present disclosure; and

FIG. 33 is an exemplary block diagram of a transportation device provided in accordance with another embodiment of the present disclosure;

fig. 34 is a schematic view of a light source section and a light-conducting element in a backlight provided by an embodiment of the disclosure.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present disclosure more apparent, the technical solutions of the embodiments of the present disclosure will be described clearly and completely with reference to the drawings of the embodiments of the present disclosure. It is to be understood that the described embodiments are only a few embodiments of the present disclosure, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the described embodiments of the disclosure without any inventive step, are within the scope of protection of the disclosure.

Unless otherwise defined, technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this disclosure belongs. The use of "first," "second," and the like in this disclosure is not intended to indicate any order, quantity, or importance, but rather is used to distinguish one element from another. The word "comprising" or "comprises", and the like, means that the element or item listed before the word covers the element or item listed after the word and its equivalents, but does not exclude other elements or items.

The terms "parallel," "perpendicular," and "the same" as used in the embodiments of the present disclosure include strictly "parallel," "perpendicular," "the same," and the like, and the terms "substantially parallel," "substantially perpendicular," "substantially the same," and the like, include certain errors, which are within an acceptable range of deviation for a particular value, as determined by one of ordinary skill in the art, in view of the error associated with measuring the particular value (e.g., the limitations of the measurement system). For example, "substantially" can mean within one or more standard deviations, or within 10% or 5% of the stated value. When the number of one component is not particularly specified in the following of the embodiments of the present disclosure, it means that the component may be one or more, or may be understood as at least one. "at least one" means one or more, and "a plurality" means at least two.

In the research, the inventors of the present application found that: a backlight source in a general display device needs to set a longer light mixing distance to ensure uniformity of light emission, and setting the longer light mixing distance of the backlight source will result in a larger thickness of the display device, which affects portability of the display device.

The embodiment of the disclosure provides a light source device, a display device, a head-up display and traffic equipment. The light source device, the display device, the head-up display, and the transportation apparatus each include a light-transmitting element 200, as shown in fig. 1A to 28, 32, and 34, the light-transmitting element 200 includes a light out-coupling member array 220, and the light out-coupling member array 220 includes a plurality of light out-coupling members 221. For example, for each of at least some of the light outcouplers 221, a portion of the light rays incident to the light outcoupler is reflected by the light outcoupler and another portion is transmitted by the light outcoupler. For example, in some embodiments, light reflected by the light out-coupling member exits from the light exit region of the light transmissive element 200 and passes through the display panel 10, and light transmitted by the light out-coupling member passes through the light out-coupling member and continues to propagate in the light transmissive element 200, as shown in fig. 1A to 28, 32 and 34; alternatively, in other embodiments, the light transmitted by the light out-coupling member exits from the light exit region of the light transmissive element and passes through the display panel, and the light reflected by the light out-coupling member passes through the light out-coupling member and continues to propagate in the light transmissive element. By using a light-conducting element with a plurality of light outcoupling means, it is advantageous to improve the uniformity of the light.

In some embodiments, as shown in fig. 1A to 28 and 32, an optical axis (chief light, also called principal ray) of a light ray transmitted through at least a part of the light outcoupling members 221 intersects with an extending direction of a light outgoing side of the light conducting element (an arrangement direction of the part of the light outcoupling members, which is illustrated by taking a horizontal direction as an example in the drawings), which is advantageous for reducing the thickness of the backlight in the display device. Alternatively, in some embodiments, the manner in which light rays propagate in the light conducting element in the embodiments of fig. 1A-28 and 32 may be replaced by: the optical axis of the light transmitted through at least part of the light outcoupling members 221 is along the extending direction of the light outgoing side of the optical waveguide element 200, as shown in fig. 34.

In some embodiments, the last light outcoupling element 221 in the direction of said light rays propagating in sequence may comprise a light outcoupling element and/or comprise a reflective film. For example, the reflective film may cause the last light out-coupling element to have the largest reflectivity among the plurality of light out-coupling elements, and/or the reflective film may totally or substantially totally reflect all or selected light rays incident thereon. Substantially all reflections may be considered to be all reflections within an error tolerance. For example, the selected light may be a selected polarized light, such as P-polarized light, S-polarized light, or other polarized light, or a particular wavelength of polarized light. The last light out-coupling piece adopts the mode of reflective coating, is favorable to improving the light reflectivity of last light out-coupling piece to be favorable to improving the light efficiency, improving luminance, reduction consumption.

In some embodiments, the reflective film comprises, for example, a selectively reflective film and/or a non-selectively reflective film. For example, the selective reflective film may include a polarizing reflective film, for example, the polarizing reflective film may include a polarizing transflective film and/or a polarizing absorbing film. For example, the selective reflection film may include a polarization reflection film as well as a wavelength selective reflection film.

In some embodiments, the plurality of light outcoupling members 221 in the light conducting element 200 may be a gas (e.g., air) or a transparent optical medium (e.g., a polymer material, glass, quartz, or the like) between them.

In some embodiments, the reflective film is a plated reflective film or an adhesively disposed reflective film or a separately disposed reflective film. The plated or attached reflective film may be disposed on the transparent optical medium of the light-conducting component 200; the separately disposed reflective film may not be attached to the transparent optical medium, for example, the separately disposed reflective film may be in direct contact with a gas (for example).

In some embodiments, in case the last light outcoupling member comprises a reflective film, the optical axis of the light ray transmitted through the partial light outcoupling member 221 and the extending direction of the light exit side of the light conductive element 200 may intersect or substantially follow the extending direction of the light exit side.

In some embodiments, the display device includes a display panel and a backlight source, the display panel includes a display surface and a back side opposite to the display surface, the backlight source is located at the back side of the display panel, and emergent light emitted from a light-emitting side of the backlight source is transmitted through the display panel to obtain image light.

In some embodiments, the backlight may be a side-in type backlight, for example, the backlight includes light source portions 100 incident on the light-transmitting element 200 from the sides of the light-transmitting element 200, as shown in fig. 1A to 34.

For example, in some embodiments, a display device includes: a display panel including a display surface and a back side opposite to the display surface; and a backlight source located at a back side of the display panel, the backlight source including a light conducting element, the light conducting element including a light exit area and an optical outcoupling member array, the optical outcoupling member array including a plurality of optical outcoupling members, light incident to the light conducting element after entering the light conducting element being totally reflected at least a plurality of times at the light exit area of the light conducting element and propagating to the plurality of optical outcoupling members of the optical outcoupling member array in sequence, a part of the light propagating to each of the optical outcoupling members in at least part of the optical outcoupling members being reflected by the optical outcoupling member out of the light exit area of the light conducting element and then passing through the display panel, and another part of the light propagating to each of the optical outcoupling members in at least part of the optical outcoupling members continuing to propagate in the light conducting element after passing through the optical outcoupling member.

For example, a display device includes a display panel and a backlight. The display panel comprises a display surface and a back side opposite to the display surface; the backlight source is positioned on the back side of the display panel. The backlight includes the light conduction component, the light conduction component includes play plain noodles and light-out coupling array, light-out coupling array includes a plurality of light-out coupling, the backlight still includes light source portion, light source portion is configured to make its light that sends take place a lot of total reflections and propagate to a plurality of light-out coupling array in proper order in light conduction component's play plain noodles department at least after getting into the light conduction component, a part of the light of propagating to each light-out coupling of light-out coupling array sees through display panel behind the play plain noodles of light-out coupling reflection light conduction component, another part of the light of propagating to each light-out coupling of light-out coupling array continues to propagate in the light conduction component after seeing through the light-out coupling. In the display device provided by the disclosure, the light conduction element is arranged in the backlight source, so that the brightness of the emergent light is uniform, the thickness of the backlight source is reduced, and the space in the display device is occupied, so that the display effect and the portability of the display device are improved.

In some embodiments, the source light line of the backlight includes a component of first polarized light and a component of second polarized light, the polarization states of the first and second polarized light being different, and the outgoing light ray exiting the light exit side of the backlight is polarized light and includes one of the first and second polarized light. The source light of the backlight is, for example, unpolarized light, which comprises components of the first polarized light and components of the second polarized light. In some embodiments, the display panel includes an incident-side polarizer and an exit-side polarizer, and source light of the backlight source that is unpolarized light is converted into outgoing light that is polarized light, which can improve the utilization rate of the outgoing light of the backlight source by the display panel.

For example, one of the first polarized light and the second polarized light is S polarized light, and the other is P polarized light. In some embodiments, the first and second polarizations may be other types of polarizations. For example, the polarization state of the polarized light incident on the polarizing reflective film coincides with the polarization state of the outgoing light ray outgoing from the light outgoing side of the backlight. For example, both the polarized light incident on the polarizing reflection film and the outgoing light emitted from the light outgoing side of the backlight are P-polarized light or both are S-polarized light.

In some embodiments, the backlight may further include a light conversion device including a polarization splitting element and a polarization conversion element. The polarization splitting element is configured to split the source light incident to the polarization splitting element into first polarized light and second polarized light, and the polarization conversion element is configured to convert one of the first polarized light and the second polarized light into the other. In some embodiments, the light conversion device may further include a reflection element configured to reflect the first polarized light or the second polarized light obtained after the light splitting process by the polarization splitting element, on the basis of including the polarization splitting element and the polarization conversion element.

For example, as shown in fig. 9 and 10, the first element 310 may include a polarization splitting element, the second element 320 may include a reflective element, and one of the first element 310 and the second element 320 may include a polarization conversion element. Alternatively, as shown in fig. 14 to 21, the first element 310 (not shown in fig. 14) may include a polarization splitting element, the second element 320 may include a reflective element, and the third element 400 may include a polarization conversion element. Or, for example, as shown in fig. 29 to 31, the first element 51 may include a polarization splitting element, the second element 52 may include a reflecting element, and the third element 53 may include a polarization converting element.

For example, one of the first polarized light 1001 and the second polarized light 1002 obtained by the light splitting process may be converted by the polarization conversion element (see 400 in fig. 14 to 21 and 53 in fig. 29) after being reflected by the reflection element (see 320 in fig. 14 to 21 and 52 in fig. 29, for example), or reflected by the reflection element (see 52 in fig. 30) after being converted by the polarization conversion element (see 53 in fig. 30), or reflected by the reflection element (see 52 in fig. 31) after being first converted by the polarization conversion element (see 53 in fig. 31) and then converted by the polarization conversion element for the second time. For example, the polarization conversion element may be a half-wave plate or a quarter-wave plate. The display panel is configured to generate image light using one of the first polarized light and the second polarized light.

For example, in some embodiments shown in fig. 9 and 10, it may be that polarized light resulting after the polarization conversion element converts one of the first polarized light and the second polarized light into the other is incident to the light conduction element 200; alternatively, in some embodiments shown in fig. 14-21, it may be that one of the first polarized light and the second polarized light is converted into the other by the polarization conversion element 400 after entering the light transmissive element 200.

For example, in some embodiments, the light-transmitting element 200 includes a plurality of sub light-transmitting elements, including a first sub light-transmitting element 2001 and a second sub light-transmitting element 2002 arranged in a stack, e.g., as shown in fig. 9 and 11-16, 19-21; alternatively, as shown in fig. 10, 17, and 18, the plurality of sub light-transmitting elements includes a first sub light-transmitting element 2001 and a second sub light-transmitting element 2002 which are arranged side by side.

For example, in some embodiments, in the case where the first sub light conduction element 2001 and the second sub light conduction element 2002 are disposed in a stacked manner, as shown in fig. 14 to 16, the first light exit region of the first sub light conduction element 2001 and the second light exit region of the second sub light conduction element 2002 overlap, and light exiting from one of the first light exit region and the second light exit region passes through the polarization conversion element 400 and then propagates to the other of the first light exit region and the second light exit region; alternatively, as shown in fig. 20 and 21, the first light exit region of the first sub light conduction element 2001 and the second light exit region of the second sub light conduction element 2002 overlap, and light exiting from one of the first light exit region and the second light exit region bypasses the polarization conversion element 400 and propagates to the other of the first light exit region and the second light exit region; alternatively, as shown in fig. 18 and 24, the second sub light guiding element (see 2002 in fig. 18 and the lower sub light guiding element in fig. 24) includes a light guiding region and a second light emitting region which are sequentially arranged along the extending direction of the second sub light guiding element, the polarized light in the second sub light guiding element is reflected and propagated by total reflection and/or non-total reflection in the light guiding region and propagated to the second light emitting region and then propagated to the first sub light guiding element (see 2001 in fig. 18 and the upper sub light guiding element in fig. 24), and the light guiding region of the second sub light guiding element overlaps with the first light emitting region of the first sub light guiding element. The following describes a display device, a head-up display, and a transportation apparatus provided in an embodiment of the present disclosure with reference to the drawings.

Fig. 1A is a schematic partial cross-sectional structure diagram of a display device provided according to an example of an embodiment of the present disclosure. As shown in fig. 1A, the display device includes a display panel 10 and a backlight 20. The display panel 10 includes a display surface 10-01 and a back side 10-02 opposite the display surface 10-01, and the backlight 20 is located on the back side 10-02 of the display panel 10. For example, light emitted from the backlight 20 is transmitted through the display panel 10 and then emitted to the observation area 30. For example, the side of the display panel 10 facing the backlight 20 is a non-display side, the side of the display panel 10 away from the backlight 20 is a display side, and the observation area 30 is located on the display side of the display panel 10, which is the side where a user can view a display image. For example, the viewing area 30 and the backlight 20 are located on both sides of the display panel 10.

For example, the light outcoupling means comprises a light outcoupling means. For example, the array of light out-couplers comprises an array of light out-couplers. For example, the set of light outcoupling means comprises a set of light outcoupling means. The light outcoupling means may also be a grating, such as a transmissive grating or a reflective grating, or a scattering dot structure, for example. For example, the light outcoupling element comprises an optical film having a transmissive and reflective function, which may transmit part of the light and reflect part of the light.

As shown in fig. 1A, the backlight 20 includes a light source section 100 and a light conductive element 200, the light conductive element 200 includes a light exit region and a light outcoupling member array 220, and the light outcoupling member array 220 includes a plurality of light outcoupling members 221. For example, after entering the light guide member 200, the light incident on the light guide member 200 is totally reflected for a plurality of times at least at the light exit region/light exit side (light exit surface 211, the light exit surface 211 is schematically illustrated in the following embodiments) of the light guide member 200 and sequentially propagates to the light outcouplers 221 of the light outcoupler array 220. For example, the light source unit 100 is configured such that light emitted therefrom, after entering the light guide member 200, is totally reflected multiple times at least at the light exit surface 211 of the light guide member 200 and sequentially propagates to the light outcouplers 221 of the light outcoupler array 220, a part of the light propagating to each light outcoupler 221 of the light outcoupler array 220 is reflected by the light outcoupler 221 out of the light exit region of the light guide member 200 and then passes through the display panel 10, and another part of the light propagating to each light outcoupler 221 of at least some of the light outcouplers continues to propagate in the light guide member 200 after passing through the light outcoupler 221.

For example, the light exit region of the light-transmitting member 200 includes the light exit surface 211. For example, the light emitting surface 211 may be at least one of a plane surface or a curved surface. For example, the light emitting surface 211 may include a grating or scattering dots distributed thereon. As an example, in some embodiments of the present disclosure, the light exiting region includes the light exiting surface 211 as an example for explanation, but should not be considered as a limitation to the present disclosure.

In the embodiment of the disclosure, the light conducting element is arranged in the backlight source, so that the brightness of the emergent light is uniform, the thickness of the backlight source is reduced, and the space in the display device is occupied, so that the display effect and the portability of the display device are improved.

For example, as shown in fig. 1A, the light guiding element 200 further includes a waveguide medium 210, the light emitted by the light source unit 100 enters the waveguide medium 210 and is propagated by total reflection in the waveguide medium 210, a part of the light propagated to each light outcoupling member 221 of the light outcoupling member array 220 is reflected by the light outcoupling member 221 out of the light guiding element 200, and another part of the light is propagated by total reflection after being transmitted by the light outcoupling member 221.

For example, the light outcoupling member array 220 includes a plurality of light outcoupling members 221, and light rays propagating to the respective light outcoupling members 221 are transmitted and reflected on the light outcoupling members 221. For example, a part of the light incident on the surface of the light outcoupling member 221 is reflected by the light outcoupling member 221 out of the light conduction element 200, and another part of the light is transmitted by the light outcoupling member 221 and then continuously propagates to the next light outcoupling member 221 by total reflection, and the light is transmitted and reflected on the next light outcoupling member 221, and the transmitted light is continuously propagated to the light outcoupling member 221 farthest from the light source unit 100 by total reflection (for example, the light is transmitted by the light outcoupling members in sequence until the light outcoupling member farthest from the light source unit).

For example, all or part of the light rays transmitted to the light outcoupling member farthest from the light source part (which may also be considered as the last light outcoupling member in the light propagation direction) may be reflected by the light outcoupling member, and the disclosed embodiments are not limited thereto.

For example, light propagating to the last light out-coupling member (e.g., light out-coupling member) is totally or partially reflected out of the light-exiting region of the light-transmitting member and then transmitted through the display panel. For example, the light is converted into image light after passing through the display panel.

For example, as shown in fig. 1A, the light exit region/side (e.g., light exit surface 211) of the light guide member 200 and the display surface 10-01 of the display panel 10 are stacked in a direction perpendicular to the display surface 10-01, and the light source unit 100 is located at the side of the light guide member 200. In the embodiment of the present disclosure, the light conducting element is located below the display panel, and the light source portion is located at a side of the light conducting element, but the embodiment is not limited thereto. For example, the display panel 10 includes a display surface for displaying images, and the light emitting surface of the light-transmitting member 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 on a side of the display panel 10; the light source unit 100 is located at a side of the light guide member 200, and the backlight 20 is a side-in type backlight, for example.

For example, the light source section 100 is configured to output collimated light. For example, the light source unit 100 includes a light source and a collimating element configured to convert light emitted from the light source with a certain divergence angle into collimated light. The term "collimated light" refers to parallel or nearly parallel light, and the collimated light output by the light source unit 100 can satisfy the total reflection condition as much as possible.

For example, the light source may be a monochromatic light source that ultimately forms a monochromatic image, or a color-mixed light source that forms a color image, such as a red monochromatic light source, a green monochromatic light source, a blue monochromatic light source, or a white color-mixed light source. For example, the light source may be a laser light source or a Light Emitting Diode (LED) light source. For example, the light source section may include one light source or a plurality of light sources.

For example, the collimating element may comprise a convex lens, a concave lens, or a fresnel lens, or any combination of the above.

For example, the collimating element may comprise a convex lens, and the light source may be arranged near the focal point of the convex lens, whereby divergent light emitted by the light source may be converted into parallel or nearly parallel collimated light rays after passing through the lens.

For example, fig. 2 is a schematic plan view of a backlight according to the example shown in fig. 1A. As shown in fig. 2, the light emitted from the light source included in the light source unit 100 may be a one-dimensional light beam, for example, a light beam that extends mainly in a one-dimensional direction. For example, the light source section 100 may include a stripe light source that emits a light beam having a cross section that is approximately linear in one dimension, or may be narrow-band.

For example, fig. 3 is a schematic plan view of another backlight according to the example shown in fig. 1A. As shown in fig. 3, at least some of the light outcouplers 221 of the plurality of light outcoupler arrays 220 included in the light outcoupler array 220 are sequentially arranged in a first direction and extend in a second direction crossing the first direction. For example, the number of the light out-couplers 221 may be 2 or more. The first direction may be an X direction and the second direction may be a Z direction, but is not limited thereto, and the first direction and the second direction may be interchanged.

For example, as shown in fig. 3, the light source of the light source part 100 may include a plurality of sub light sources 101 aligned in the second direction, the plurality of sub light sources 101 being configured to emit light rays entering at least part of the light outcoupling member 221. For example, the sub-light sources 101 may be point light sources, the light source section 100 may be a combination of a plurality of point light sources, and the plurality of sub-light sources 101 may be arranged in a line along the second direction, so that the light beams emitted from the light sources may be regarded as one-dimensional light beams. In the embodiment of the disclosure, the plurality of independent sub-light sources are arranged, so that the sub-light sources can be conveniently replaced and disassembled, for example, when any sub-light source is damaged, the sub-light source can be repaired through independent disassembly and assembly, the whole replacement is not required like a strip-mounted lamp strip, and the cost can be saved.

For example, fig. 4A is a schematic plan view of another backlight according to the example shown in fig. 1A. As shown in fig. 4A, the light out-coupling element array 200 includes a plurality of light out-coupling elements 220 extending along the second direction, the light source unit 100 includes a plurality of beam expanding units 102 arranged along the second direction and sub-light sources 101 located at one side of the plurality of beam expanding units 102 in the second direction, the plurality of beam expanding units 102 are configured to expand light emitted by the sub-light sources 101 along the second direction, and the expanded light is configured to be transmitted to the light out-coupling element array 220.

For example, the light source section 100 may include a light source that is a single point light source 101 that emits a single point light beam. For example, the point light source can be a laser light source, the light beam cross section of the light source is very small, and the light energy is highly concentrated, so that the light beam emitted by the point light source can be expanded in a one-dimensional direction, and the expanded light is converted into a surface light source through the waveguide medium and the optical coupling element array.

For example, as shown in fig. 4A, light emitted from the point light source 101 first passes through the plurality of beam expanding portions 102 to be expanded in the second direction, and then is transmitted to the light outcoupling element array 220 in the first direction. For example, when the light emitted from the point light source 101 propagates in an extended and expanded manner, the light may propagate along any one or more of a reflection path, a total reflection path, and a straight path.

For example, the beam expanding portion 102 may be a grating, or may also be another array of light out-coupling elements, which is not limited by the embodiments of the present disclosure.

For example, the light source may introduce light into the light-conducting element in a lateral approach, which may avoid further increasing the thickness of the backlight.

For example, when the backlight provided by the embodiment of the present disclosure is applied to a display device with a high requirement on brightness, such as a head-up display, a light source (e.g., a lamp strip or a plurality of point light sources arranged linearly) emitting a one-dimensional light beam is used to provide the backlight with high brightness, and the scheme is simple and easy to implement.

For example, fig. 4B is a schematic structural diagram of another backlight. The backlight shown in fig. 4B differs from the backlight shown in fig. 4A in that the beam expanding section is located in the light-transmitting member.

For example, as shown in fig. 1A, the light guiding element 200 further includes a light incoupling portion 230 located at a side of the light outcoupling member array 220 facing the light source portion 100, and configured such that light rays entering the light guiding element 200 satisfy a total reflection condition to propagate with total reflection in the waveguide medium 210. The embodiments of the present disclosure are not limited to the light guide element including the light incoupling portion, for example, the light guide element may not include the light incoupling portion, and when an angle of a light ray incident to the waveguide medium satisfies a total reflection condition, the light ray may realize total reflection propagation in the waveguide medium.

For example, the refractive index of the waveguide medium is n1, the refractive index of the optically thinner medium (e.g., air) other than the waveguide medium is n2, and the incident angle when the light enters the waveguide medium or the incident angle after passing through the optical coupling portion is not less than the critical angle arcsin (n 2/n 1) of total reflection, the light satisfies the total reflection condition.

For example, the light incoupling part 230 in the embodiment of the present disclosure may include at least one of a surface grating, a bulk grating, a blazed grating, a prism and a reflective structure, and guides the light emitted from the light source to satisfy the total internal reflection condition by entering the light into the waveguide medium through at least one of reflection, refraction and diffraction effects.

For example, as shown in fig. 1A, the light-transmitting element 200 includes two first main surfaces 211 and second main surfaces 212 opposite to each other, and the light incoupling part 230 may be disposed on the first main surface 211 and the second main surface 212, or may be disposed on a side surface connecting the two main surfaces. For example, the two major surfaces of the light-conducting element may also be referred to as the two major surfaces of the waveguide medium. For example, the array of light outcoupling elements is located between the first main surface and the second main surface. For example, the light may propagate at least totally reflected on the first main surface and/or the second main surface, and there may be partial non-total reflection, such as specular reflection.

For example, when the light-transmitting element includes a plurality of sub light-transmitting elements, for example, the plurality of sub light-transmitting elements are arranged to overlap in a direction perpendicular to the first main surface, the upper surface of the sub light-transmitting element on the uppermost side is the first main surface, and the lower surface of the sub light-transmitting element on the lowermost side is the second main surface.

For example, when the light-transmitting member includes a plurality of sub light-transmitting members, the plurality of sub light-transmitting members are arranged in a direction parallel to the display surface. For example, the plurality of sub light-conducting elements are arranged to overlap in a direction perpendicular to the display panel and partially overlap in a direction parallel to the display surface.

For example, the first and second

main surfaces

211 and 212 include an upper surface 211 close to the display panel 10 and a lower surface 212 far from the display panel 10, and the light incoupling part 230 may be disposed on the upper surface 211 or the lower surface 212 on a side of the light outcoupling member array 220 facing the light source part 100. For example, the first direction (X direction) and the second direction (Z direction) are parallel to the above-described main surface.

For example, the waveguide medium 210 is made of a material that performs the function of a waveguide, typically a transparent material with 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), high molecular polymers, iii-v semiconductor compounds, glass, and the like.

For example, the waveguide medium 210 may be a planar substrate, a stripe-shaped substrate, a ridge-shaped substrate, and the like. For example, in at least one example of the disclosed embodiment, the waveguide medium employs a planar substrate to form a uniform surface light source.

For example, as shown in fig. 1A to 3, the light outcoupling element array 220 comprises a plurality of light outcoupling elements 221 arranged along a total reflection propagation direction of light rays, which may refer to a direction of the entirety (macro) of the propagation of light rays, for example, here, a first direction (e.g., X direction) shown in fig. 1A, and light rays entering the light conducting element 200 are totally internally reflected at both main surfaces of the waveguide medium 210, so that the entirety of the light rays propagates to the light outcoupling element array 220 along the X direction.

For example, as shown in fig. 1A to 3, the light outcoupling member 221 is configured to transmit light while reflecting light. For example, when the light guided by total reflection in the waveguide medium 210 is transmitted to the light outcoupling member 221, the light is reflected at the light outcoupling member 221, and the angle of the reflected light no longer satisfies the total reflection condition, and then exits; the transmitted light continues to propagate along the total reflection path, continues to be transmitted to the next light outcoupling member 221, continues to be reflected and transmitted, the light reflected by the next light outcoupling member 221 exits from the light conduction element 200, and the light transmitted by the next light outcoupling member 221 continues to propagate along the total reflection path; and so on until the last light out-coupling member 221 is transmitted.

For example, as shown in fig. 1A, the light outcoupling member 221 may be disposed in the waveguide medium 210 in a plated or pasted manner. For example, the waveguide medium 210 may be divided into a plurality of cylinders having a parallelogram cross section, and the light outcoupling members 221 are disposed between the spliced cylinders, for example, the medium between adjacent light outcoupling members 221 may be the waveguide medium 210. For example, the waveguide medium 210 includes a plurality of waveguide sub-media arranged along a first direction and attached to each other, an optical out-coupling member 221 is sandwiched between adjacent waveguide sub-media, each waveguide sub-medium is configured to cause total internal reflection of light, and the optical out-coupling member is configured to couple a part of light out of the optical transmission element by reflecting a total reflection condition that destroys the part of light.

For example, the embodiment of the present disclosure is described with an example in which the plurality of light outcoupling members 221 in the light outcoupling member array 220 are all parallel to each other, for example, light rays exiting from the light outcoupling member array are parallel light. However, the embodiments of the present disclosure are not limited thereto, and a plurality of light outcoupling elements in the light outcoupling element array may also be non-parallel, and by adjusting an included angle between the plurality of light outcoupling elements, light emitted from the light outcoupling element array may be adjusted to convergent light or divergent light.

For example, as shown in fig. 1A, an included angle between each light coupler 221 and the light emitting surface 211 is a first included angle, and a sum of the first included angle and a critical angle of total reflection of light is in a range of 60 ° to 120 °. For example, the critical angle for total reflection may be a critical angle for total reflection when a light ray propagates in the light-transmitting member. For example, the critical angle of total reflection may be a critical angle at which light is totally reflected at the light emitting surface 211. For example, the sum of the first angle and the critical angle for total reflection is in the range of 70 ° to 120 °. For example, the sum of the first angle and the critical angle for total reflection is in the range of 80 ° to 100 °. For example, the sum of the first angle and the critical angle for total reflection is in the range of 85 ° to 95 °. This disclosed embodiment is through setting up the first contained angle between optical coupler piece and the play plain noodles and the critical angle of total reflection of light when the play plain noodles takes place the total reflection, to same way light, can make light only take place once reflection in each optical coupler piece, for example can avoid taking place transmission and reflection with the parallel or near parallel light of optical coupler piece above that, can improve the homogeneity of light, reduce or avoid stray light's production.

For example, the included angle between each light outcoupling member 221 and the first main surface 211 is a first included angle, the included angle between the light totally reflected and propagated in the waveguide medium 210 and the first main surface 211 and the second main surface 212 is a second included angle, and the difference between the first included angle and the second included angle is not more than 10 degrees. For example, the difference between the first included angle and the second included angle is not greater than 5 degrees. For example, the first included angle and the second included angle are equal, for example, it may be considered that the light totally reflected and propagated in the waveguide medium 210 is parallel to the light outcoupling member 221, and for the same path of light, the light may be reflected once in each light outcoupling member, for example, transmission and reflection of the light parallel to the light outcoupling member are avoided, so that uniformity of the light may be improved, and generation of stray light may be reduced or avoided.

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

For example, fig. 1B is a partial structural schematic diagram of another display device. Fig. 1B differs from the example shown in fig. 1A in that a reflecting device 600 is disposed on a side of the light conducting element 200 away from the display panel 10, in which case an angle between the light outcoupling member 221 and the light propagated by total reflection may not be limited, and may be non-parallel, for example, greater than 10 degrees, and the stray light leaked may be reflected back by disposing a reflecting device on a side of the light conducting element away from the display panel to improve uniformity of light exiting from the light conducting element. For example, the reflecting means may be a reflecting layer or other reflecting structure.

For example, as shown in fig. 1A to 3, the embodiments of the present disclosure schematically show that orthographic projections of adjacent light outcoupling members 221 on the main surface meet each other, and a dark region where light is not emitted between the two light outcoupling members can be avoided. But not limited to this, adjacent light-out-coupling piece can be partly overlapped at the orthographic projection of main surface, can avoid the weakening of light at the light-out-coupling piece edge, and the overlap through light-out-coupling piece can make the light-emitting more even.

For example, as shown in fig. 1A to 3, in a direction in which light is totally reflected and propagates in the waveguide medium 210, the plurality of light outcoupling members 221 are uniformly arranged and the reflectivity gradually increases. For example, the reflectance of the light outcoupling element 221 closer to the light source section 100 is smaller. For example, the reflectivity of the light out-coupling members arranged in sequence along the extending direction of the light-emitting surface in the light out-coupling member array gradually increases (e.g., increases one by one) or gradually increases regionally in the propagation direction of the light. For example, the arrangement density of the light outcoupling elements arranged in sequence along the extending direction of the light extraction surface in the light outcoupling element array gradually increases or gradually increases regionally. For example, the regional increase may be two or more regions, where the reflectance of the light outcoupling means is different and gradually increases in the different regions.

The above-mentioned uniform arrangement may refer to either an arrangement in which adjacent light outcoupling members are arranged so that orthographic projections meet each other, or an arrangement in which adjacent light outcoupling members are arranged so that orthographic projections partially overlap. Because light can reflect the waveguide medium step by step in the propagation, the light intensity can attenuate step by step, through the difference that sets up each light coupling-out piece's transflective nature, for example along the route of light total reflection propagation, the reflectivity of light coupling-out piece increases gradually, can make the light intensity that each light coupling-out piece reflects out more even, and the light-emitting of each part of waveguide medium 210 is more even.

For example, the arrangement density of the plurality of light outcoupling members gradually increases in a direction in which light is propagated by total reflection in the waveguide medium. For example, the closer the distance between the light source units, the lower the arrangement density of the light outcoupling elements. For example, the position where the arrangement density is small may be where adjacent light out-coupling elements are arranged such that orthographic projections meet each other, and the position where the arrangement density is large may be where adjacent light out-coupling elements are arranged such that orthographic projections partially overlap. For example, the positions with a small arrangement density may be positions where adjacent light out-coupling members are arranged such that orthographic projections overlap each other with a small overlapping portion, and the positions with a large arrangement density may be positions where adjacent light out-coupling members are arranged such that orthographic projections overlap each other with a large overlapping portion. The embodiment of the present disclosure may also set the transflective property of each light outcoupling member to be the same or almost the same, and make the intensity of the light reflected by each light outcoupling member uniform by adjusting the arrangement density of the light outcoupling members.

For example, fig. 5 is a schematic plan view of another backlight according to the example shown in fig. 1A. The backlight shown in fig. 5 differs from the backlight shown in fig. 3 in that the reflectivity of the light out-coupling elements in the array of light out-coupling elements varies. For example, as in the example shown in fig. 5, the light out-coupling element array 220 comprises at least two regions, e.g. a region 01 and a region 02, the average reflectivity of the light out-coupling elements 221 in one of the at least two regions 01 being greater than the average reflectivity of the light out-coupling elements 221 in the other regions (e.g. region 02). The average reflectivity of the light outcoupling member of the area 01 is greater than the average reflectivity of the light outcoupling member of other areas, so that the light intensity in the area 01 is greater than the light intensity of other areas, and certainly, the embodiment of the present disclosure is not limited to adjusting the light intensity of the emergent light in the area by adjusting the average reflectivity of the light outcoupling member in the area, and can also adjust the intensity of the emergent light in the area by other methods.

For example, at least one light out-coupling member 221 may be included in the area 01, a plurality of light out-coupling members 221 may be included in the other area 02, and the average reflectivity of the plurality of light out-coupling members 221 in the other area is small so that the brightness of the light emitted from the light transmission member is not uniform, and the light transmission member is suitable for an application scene of non-uniform display, such as a billboard, a display that displays contents intensively in a specific area. For example, the area 01 may be located in the middle area, and the other area 02 may surround the area 01. The present disclosure is not limited thereto, for example, the reflectivity of the plurality of light outcoupling members 221 included in the region 01 may be gradually increased (e.g., increased one by one), and the reflectivity of the plurality of light outcoupling members 221 in other regions may be all the same to make the brightness of the light emitted from the light conductive element uneven.

For example, the light outcoupling element 221 may have no wavelength selectivity and polarization selectivity for light transmission and reflection, and for example, an inorganic dielectric film, such as a film formed by stacking one or more metal oxide/metal nitride films, may be used, wherein the thickness of each film is about 10nm to 1000nm, and the overall transmission and reflection performance of the inorganic dielectric film can be controlled by changing the material of the film and/or the stacking manner of the films. Thus, the wavelength property and polarization property of the light incident to the light outcoupling member 221 after being transmitted and reflected by the light outcoupling member 221 are hardly changed.

For example, at least one light outcoupling member 221 of the light outcoupling member array 220 comprises a light-transmitting film, the light entering the light-conducting element 200 comprises a first polarized light and a second polarized light, the light-transmitting film is configured such that the reflectivity for the first polarized light is larger than the reflectivity for the second polarized light, and the transmissivity for the second polarized light is larger than the transmissivity for the first polarized light, whereby the light outcoupling member may gradually reflect the first polarized light out of the light-conducting element.

The light entering the light conducting element may be unpolarized light or may be polarized light in two polarization states. The term "unpolarized light" as used herein means that light emitted from the light source unit may have a plurality of polarization characteristics at the same time but does not exhibit unique polarization characteristics, and for example, light emitted from the light source unit may be considered to be composed of two orthogonal polarization states, and unpolarized light emitted from the light source unit may be considered to be decomposed into two orthogonal polarization states.

For example, the light-transmitting film may be a Brightness Enhancement Film (BEF) having a high reflectivity for one polarized light and a high transmittance for another polarized light (e.g., the light-transmitting film has a high reflectivity for S-polarized light and a high transmittance for P-polarized light), and the light-outcoupling member may utilize the selectivity of polarization transmittance and reflectance so that light is gradually reflected by the light-outcoupling member out of the light-conducting element.

For example, as shown in fig. 1A, when light rays exiting from the light outcoupling element array 220 exit without satisfying the total reflection condition, the exiting direction may be a direction perpendicular to the main surface of the waveguide medium 210.

Fig. 6 is an example where the light rays exiting the array of light outcoupling elements are not perpendicular to the main surface of the waveguide medium. As shown in fig. 6, when the angle of light incident to the light out-coupling element is changed, and/or the angle between the light out-coupling element and the major surface is changed, the light exiting from the array of light out-coupling elements may also be non-perpendicular to the major surface of the waveguide medium.

In the embodiment of the disclosure, the light emitted from the light outcoupling element array may be perpendicular or not to the main surface of the waveguide medium, and the light emitted from different light outcoupling elements may have parallel or nearly parallel emission directions, so as to form a collimated light beam. In the embodiment of the disclosure, the light transmission element with smaller thickness is adopted to convert the light output by the light source into the collimated light of the surface light source, so that the thickness of the display device can be saved.

Fig. 7 is a schematic view of a partial structure of a backlight in another example according to an embodiment of the present disclosure. The example shown in fig. 7 is different from the example shown in fig. 1A in the number of light source parts and the arrangement of the light out-coupling members, and the positional relationship of adjacent light out-coupling members may be the same as the example shown in fig. 1A. As shown in fig. 7, the light outcoupling element array 220 comprises a first light outcoupling element group 2201 and a second light outcoupling element group 2202 arranged in a first direction, each light outcoupling element group comprising a plurality of light outcoupling elements 221 arranged in the first direction, the light outcoupling elements 221 of different light outcoupling element groups being non-parallel. For example, fig. 7 schematically illustrates that the plurality of light outcoupling elements comprised by each light outcoupling group are parallel to each other, and that the light outcoupling elements in different light outcoupling groups are not parallel.

For example, as shown in fig. 7, the backlight further includes a light source section 100, the light source section 100 includes a first light source section 110 and a second light source section 120, the first light source section 110 and the second light source section 120 are respectively located on both sides of the light outcoupling element array 220 in the first direction, the first light outcoupling element group 2201 is configured to reflect light entering the light conductive element 200 from the first light source section 110, and the second light outcoupling element group 2202 is configured to reflect light entering the light conductive element 200 from the second light source section 120. For example, the first light out-coupling group 2201 is configured to reflect only light entering from the first light source section 110, and the second light out-coupling group 2202 is configured to reflect only light entering from the second light source section 120. The embodiment of the present disclosure can improve the intensity of the outgoing light of the light guide element by providing two light source portions and two sets of light outcoupling groups.

For example, as shown in fig. 7, an angle between one of the light outcoupling members 221 in the first light outcoupling member group 2201 and the light outcoupling member 221 in the second light outcoupling member group 2202 and the first direction (the direction indicated by the arrow of X) is an acute angle, and an angle between the other and the first direction is an obtuse angle, the first light outcoupling member group may reflect only light entering from the first light source section, and the second light outcoupling member group may reflect only light entering from the second light source section. For example, the inclination directions of the light outcoupling members 221 in the first light outcoupling member group 2201 and the light outcoupling members 221 in the second light outcoupling member group 2202 are different.

For example, the light source section may also be located between the first and second light outcoupling groups in the direction of extension of the light outcoupling surface.

For example, the backlight source may further include a reflection device disposed on the other side away from the light exit side of the light conduction element, for reflecting the light leaked from the light conduction element back to the light conduction element, so that as much light as possible is converted into collimated light and output, thereby improving the light utilization rate.

For example, fig. 8 is a schematic partial structure diagram of a backlight in another example according to an embodiment of the present disclosure. The example shown in fig. 8 is different from the example shown in fig. 1A in the number of light source portions and the exit direction of the light rays reflected by the light source portions by the light outcoupling members. As shown in fig. 8, the light source part 100 includes a first light source part 110 and a second light source part 120, and the first light source part 110 and the second light source part 120 are respectively located at both sides of the light outcoupling element array 220 in the first direction. For example, both side surfaces of each light outcoupling member 221 may reflect light entering from the first light source 110 or the second light source 120, so that both side main surfaces of the light transmission element are light exiting surfaces.

For example, the reflectivity of the light outcoupling elements at and/or near the middle position is larger than the reflectivity of the light outcoupling elements at the two side positions, so that the light exiting from the light conductive element has a better uniformity. The backlight in this example can be applied to scenes requiring two-sided light emission, such as billboards and the like.

For example, fig. 9 is a schematic partial structure diagram of a backlight in another example according to an embodiment of the present disclosure. As shown in fig. 9, the backlight further includes a light splitting element 300 located between the light source section 100 and the light conducting element 200, and the light splitting element 300 is configured to split the light incident to the light splitting element 300 into a plurality of sub-beams. For example, the light splitting element 300 is configured to split the light emitted from the light source section 100 to the light guide member 200 into a plurality of sub-beams. For example, the light emitted from the light source unit 100 may be directly emitted to the light splitting element 300, or may be emitted to the light splitting element 300 after passing through another element. For example, the light splitting element 300 may split the light emitted from the light source 100 to the light conduction element 200 into two sub-beams or three sub-beams, but the embodiment of the disclosure is not limited thereto and may also split into more sub-beams. For example, the light splitting element 300 may be a prism.

For example, as shown in fig. 9, the light-transmitting element 200 includes a plurality of sub light-transmitting elements 201, and a plurality of sub light beams are configured to enter the plurality of sub light-transmitting elements 201 and be reflected out of the light-transmitting element 200 by the light out-coupling element arrays 221 located in the respective sub light-transmitting elements 201. For example, the light out-coupler array comprises a plurality of sub light out-coupler arrays respectively located in a plurality of sub light-conducting elements. For example, the plurality of sub light out-coupling member arrays correspond to the plurality of sub light-transmitting elements one to one.

For example, the number of the plurality of sub light-transmitting elements 201 may be the same as the number of the plurality of sub light beams configured to enter the corresponding sub light-transmitting elements one by one. The embodiments of the present disclosure are not limited thereto, and the number of the plurality of sub light-transmitting elements may also be smaller than the number of the plurality of sub light beams, and at least two sub light beams enter the same sub light-transmitting element.

For example, the thickness of the plurality of sub light-transmitting members 201 is smaller than the thickness of the light-transmitting members in the embodiment shown in fig. 1A; the light originally transmitted in one light conduction element is split into a plurality of thinner waveguide elements respectively, the light is transmitted in the waveguide elements with smaller thickness, the total reflection times can be increased, and the light-emitting distribution can be more uniform. For example, the uniformity in this embodiment may be light brightness uniformity, in which the light emitted from a general light source (such as a point light source) has a strong middle light and a dark edge portion, and after the light emitted from the light source is output by the light conduction element, the coupled collimated light is also in a state where the middle is bright and the two sides are dark, and it is difficult to adjust the brightness of the collimated light; for example, before the light emitted by the light source enters the light conduction element or is coupled out from the light conduction element, the uniformity of the light is improved, and the light of the surface light source with uniform brightness can be obtained; for example, increasing the number of total reflections of the light may improve the brightness uniformity, for example, a thinner light-conducting element may be provided for increasing the number of total reflections of the light.

In the embodiment of the disclosure, the light of the light source part is divided into a plurality of sub-beams, and the plurality of sub-light conducting elements are arranged to couple out the plurality of sub-beams entering the light source part, so that the uniformity of the light emitted from the backlight source can be further improved.

For example, the plurality of sub light-transmitting elements may be independent structures or may be integrated on the same substrate.

For example, each sub light-conducting element may include a waveguide medium, and the refractive index of the waveguide medium in different sub light-conducting elements may be the same or different, which is not limited in this disclosure.

For example, the number and arrangement of the light outcouplers included in the light outcoupler array in each sub light conduction element may be the same or different, and the embodiment of the present disclosure does not limit this.

For example, each sub light-transmitting element may or may not include a light incoupling portion. For example, when each sub light conduction element includes a light incoupling portion, the light incoupling portions of different sub light conduction elements may be the same, for example, all of the light incoupling portions may be entered in a geometric manner (for example, a non-grating incoupling manner such as prism incoupling or reflection structure incoupling), or may be different, which is not limited by the embodiment of the present disclosure.

For example, as shown in fig. 9, the light guiding element 200 comprises a plurality of sub light guiding elements 201, and the light outcoupling array 210 comprises a plurality of sub light outcoupling arrays respectively located in the plurality of sub light guiding elements 201; the backlight source further includes a light splitting element 300, wherein the light splitting element 300 is configured to split the light emitted by the light source unit 100 and emitted toward the light transmitting element 200 into a plurality of sub-beams, the sub-beams enter the sub-light transmitting elements 201, and each sub-beam entering each sub-light transmitting element 201 is reflected by the sub-light outcoupling element array in each sub-light transmitting element 201 to exit the light transmitting element 200.

For example, the light emitted from the light source unit 100 and directed to the light guide member 200 includes first characteristic light and second characteristic light having different characteristics, and the light splitting element 300 is configured to split the light emitted from the light source unit 100 and directed to the light guide member 200, so that the first characteristic light obtained by the splitting process is incident on the first sub light guide member 2011, and the second characteristic light obtained by the splitting process is incident on the second sub light guide member 2012.

For example, the first characteristic light and the second characteristic light are respectively first polarized light and second polarized light with different polarization states; alternatively, the first characteristic light and the second characteristic light are first color light and second color light having different wavelength distributions, respectively.

For example, light rays having different wavelength distributions may be considered to have different colors; for example, the first color light and the second color light have different wavelength distributions, and may have different colors.

For example, the light splitting element includes a polarization light splitting element configured to have a reflectance for one of the first polarized light and the second polarized light larger than a reflectance for the other; and/or the polarization beam splitting element is configured to have a transmittance for one of the first polarized light and the second polarized light greater than its transmittance for the other.

For example, the reflectivity of the polarization splitting element for the first polarization is greater than the reflectivity thereof for the second polarization; and/or the transmissivity of the polarization light splitting element to the second polarization light is greater than the transmissivity of the polarization light splitting element to the first polarization light; for example, the reflectivity of the polarization splitting element for the second polarization is greater than the reflectivity thereof for the first polarization; and/or the transmissivity of the polarization light splitting element to the first polarization light is larger than the transmissivity of the polarization light splitting element to the second polarization light.

For example, the polarization splitting element is 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. For example, the above reflects one of the first polarized light and the second polarized light and transmits the other, and it can be considered that only one of the first polarized light and the second polarized light is reflected and only the other is transmitted; for example, the polarization splitting element has almost 100% reflectivity for light of the first polarization and almost 100% transmittance for light of the second polarization. Alternatively, it is considered that the reflectance for one of the first polarized light and the second polarized light is high and the reflectance for the other is high, and for example, the reflectance for the first polarized light and the transmittance for the second polarized light of the polarization splitting element are 50% to 99%, respectively.

The light splitting element further includes a reflective element configured to reflect one of the first polarized light and the second polarized light.

For example, as shown in fig. 9, the plurality of sub beams include a first polarized beam 1001 and a second polarized beam 1002 with different polarization directions, the light splitting element 300 includes a polarized light splitting element 310, the polarized light splitting element 300 is configured to perform polarization splitting on the light emitted from the light source unit 100 and emitted to the light transmission element 200, so that the plurality of sub beams include the first polarized beam 1001 and the second polarized beam 1002 with different polarization states, the second polarized beam 1002 is incident on the second sub light transmission element 2012, and the first polarized beam 1001 is incident on the first sub light transmission element 2011. The polarization beam splitter transmits the second polarized light beam and reflects the first polarized light beam, but is not limited to only reflecting the second polarized light beam and transmitting the first polarized light beam. The first and second polarized beams in the embodiments of the present disclosure may be interchanged.

For example, as shown in fig. 9, the light out-coupling element of the first sub light conduction element 2011 is configured to have a reflectivity for the first polarized light greater than a reflectivity for the second polarized light, and the light out-coupling element of the second sub light conduction element 2012 is configured to have a reflectivity for the second polarized light greater than a reflectivity for the first polarized light, so that the intensity of light emitted from the backlight source can be increased, and the utilization rate of light can be increased.

Of course, the embodiments of the present disclosure are not limited thereto, and the light outcoupling members in the respective sub light conduction elements may also have no polarization selection characteristics.

For example, as shown in fig. 9, the light splitting element 300 further includes a reflecting element 320, and the reflecting element 320 is configured to reflect the first polarized light beam 1001 and propagate the reflected first polarized light beam into the first sub light conduction element 2011. The embodiments of the present disclosure are not limited thereto, and the reflective element may also be configured to reflect the second polarized light beam and propagate the reflected second polarized light beam into the second sub light-transmitting element. For example, the reflecting element may be replaced by another element having a similar function, and the reflecting element may transmit the split first polarized light beam to the first sub light-transmitting element.

For example, the light rays propagating to the elements/regions in the present disclosure may be propagating directly to the elements/regions, e.g., without propagating directly to the elements/regions through other optical elements; alternatively, the light may be transmitted to the element/region through the action of at least one of other optical elements, for example, a reflection element, a refraction element, a scattering element, a diffraction element, and a light-condensing element.

For example, after the unpolarized light beam emitted from the light source unit 100 passes through the polarization splitting element 310 having the polarization splitting function, the transmitted light beam includes P-polarized light (for example, second polarized light), and the reflected light beam includes S-polarized light (for example, first polarized light); or the transmitted light rays include S polarized light (e.g., second polarized light) and the reflected light rays include P polarized light (e.g., first polarized light), which are not limited by the embodiments of the present disclosure.

For example, the polarization splitting element 310 may have the function of transmitting light of one polarization and reflecting light of another polarization, and the polarization splitting element 310 may implement beam splitting using the transflective characteristics described above.

For example, the polarization beam splitter 310 may be a transflective film that splits the beam by transmitting a portion of the light and reflecting another portion of the light. For example, the transflective film may transmit the second polarized light among the light emitted from the light source unit 100 and reflect the first polarized light among the light emitted from the light source unit 100.

For example, the transflective film may be an optical film having a polarizing transflective function, such as an optical film that can split an unpolarized light ray into two different polarized lights by transmission and reflection, such as an optical film that can split a light ray into two polarized lights perpendicular to each other; the optical film can be formed by combining a plurality of film layers with different refractive indexes according to a certain stacking sequence, and the thickness of each film layer is between 10 and 1000 nm; the material of the film layer can be selected from inorganic dielectric materials, such as metal oxides and metal nitrides; high molecular materials such as polypropylene, polyvinyl chloride or polyethylene may also be selected.

For example, the transmitted P-polarized light enters the second sub light transmitting element 2012 through the second light incoupling part 232 in the second sub light transmitting element 2012, and the reflected S-polarized light enters the first light incoupling part 231 in the first sub light transmitting element 2011 after being reflected by the reflecting element 320 to enter the first sub light transmitting element 2011. The S polarized light and the P polarized light are output in a state of collimated light through the light coupler arrays in the respective waveguide elements, and the effect of converting a common light source into a uniform surface light source can be realized.

For example, as shown in fig. 9, the plurality of sub light-conducting elements are overlapped in a direction perpendicular to the display surface of the display panel, so that the brightness of the backlight source can be improved, and the uniformity of light can be improved. The overlapping arrangement includes a completely overlapping arrangement and a partially overlapping arrangement, for example, orthographic projections of the plurality of sub-light-transmitting elements on a plane parallel to the light-emitting surface of the light-transmitting element may completely overlap or partially overlap, which is not limited by the embodiment of the disclosure. Fig. 9 schematically illustrates a first sub light-transmitting element and a second sub light-transmitting element being disposed to completely overlap.

For example, as shown in fig. 9, the first sub light conduction element 2011 and the second sub light conduction element 2012 overlap in a direction perpendicular to the display surface of the display panel, for example, the first sub light conduction element 2011 and the second sub light conduction element 2012 overlap in the Y direction, and the light emitted from the second sub light conduction element 2012 passes through the first sub light conduction element 2011 and is emitted to the display panel. For example, as shown in fig. 9, the light emitted from the second sub light conduction element 2012 may or may not pass through the light out-coupling element array in the first sub light conduction element 2011, which is not limited in the embodiment of the present disclosure.

For example, when light exiting the second sub light-conducting element passes through the array of light out-couplers in the first sub light-conducting element, the array of light out-couplers in the first sub light-conducting element has a higher transmittance for the transmitted light.

For example, as shown in fig. 9, an angle between the first polarized light beam 1001 transmitted to the light out-coupling element of the first sub light conduction element 2011 and the light out-coupling element is a third angle, an angle between the second polarized light beam 1002 transmitted to the light out-coupling element of the second sub light conduction element 2012 and the light out-coupling element is a fourth angle, and a difference between the third angle and the fourth angle is not greater than 5 degrees. The third angle and the fourth angle may both refer to an angle between a light ray incident on a surface of the light outcoupling member and transmitted through the light outcoupling member and the light outcoupling member.

For example, if the third angle and the fourth angle are equal, the angle of the polarized light entering the sub light-conducting elements can be adjusted according to the inclination angle of the light outcoupling member in each sub light-conducting element. For example, setting the included angles between different sub-light-transmitting elements and the corresponding polarized light to be the same can also facilitate the fabrication of the sub-light-transmitting elements and the adjustment of the incident light angle.

For example, as shown in fig. 9, when the total reflection propagation direction of the first polarized light beam 1001 entering the first sub light conduction element 2011 is the same as the total reflection propagation direction of the second polarized light beam 1002 entering the second sub light conduction element 2012, the angle between the light out-coupling element in the first sub light conduction element 2011 and the light out-coupling element in the second sub light conduction element 2012 may be not greater than 5 degrees, for example, the light out-coupling elements in the two sub light conduction elements are parallel, so as to facilitate the fabrication of the light conduction elements.

For example, as shown in fig. 9, the included angles between the light out-coupling member in the first sub light conduction element 2011 and the light out-coupling member in the second sub light conduction element 2012 and the first direction may both be acute angles or may both be obtuse angles. For example, the light out-couplers in the first sub light conduction element 2011 and the light out-couplers in the second sub light conduction element 2012 are tilted in the same direction. The oblique direction here may refer to the oblique direction of the light outcoupling member with respect to the light exit surface. However, the tilt direction herein may also refer to a direction tilted to the left or right with respect to the Y direction.

When the direction indicated by the arrow in the X direction shown in fig. 9 is a first direction (for example, when the included angle with the direction is referred to above, the first direction may be regarded as a vector), and the total reflection propagation direction of the first polarized light beam 1001 entering the first sub light conduction element 2011 is the same as the total reflection propagation direction of the second polarized light beam 1002 entering the second sub light conduction element 2012, the total reflection propagation direction of each polarized light is the same as the first direction, and the included angle between each light coupler and the first direction may be an acute angle; when the total reflection propagation direction of each polarized light is opposite to the first direction, the included angle between each light outcoupling member and the first direction may be an obtuse angle. For example, fig. 10 is a schematic view of a partial structure of a backlight in another example according to an embodiment of the present disclosure. The example shown in fig. 10 is different from the example shown in fig. 9 in the positional relationship of the plurality of sub light-transmitting elements. As shown in fig. 10, the plurality of sub light-transmitting elements are arranged in the first direction. For example, the plurality of sub light conduction elements do not overlap in the direction perpendicular to the display surface of the display panel, so that the thickness of the backlight source can be reduced, and the degree of weakening of the light intensity at the edge of the light conduction element can be reduced by setting the length of each sub light conduction element to be smaller. For example, the sub light-transmitting members do not overlap in a direction perpendicular to the display surface of the display panel, and may be right next to each other or may be spaced apart from each other, as shown in fig. 10.

For example, the plurality of sub light-transmitting elements may include a first sub light-transmitting element 2011 and a second sub light-transmitting element 2012 arranged along a first direction, the second polarized light beam 1002 transmitted by the polarization splitting element 310 enters the second sub light-transmitting element 2012 through the second light incoupling part 232 in the second sub light-transmitting element 2012, and the reflected first polarized light beam 1001 enters the first sub light-transmitting element 2011 through the first light incoupling part 231 in the first sub light-transmitting element 2011 without being reflected by the reflecting element. The first polarized light beam 1001 and the second polarized light beam 1002 pass through the light coupler arrays in the respective sub-waveguide elements to be output in a state of collimating light, and an effect of converting a common light source into a uniform surface light source can be achieved.

For example, the total reflection propagation direction of the light in the first sub light conduction element 2011 is opposite to the total reflection propagation direction of the light in the second sub light conduction element 2012, the light out-coupling element in the first sub light conduction element 2011 is not parallel to the light out-coupling element in the second sub light conduction element 2012, for example, an included angle between one of the two and the first direction is an acute angle, and an included angle between the other and the first direction is an obtuse angle, so as to realize the light out-coupling of the light out-coupling element to the light. For example, the light out-coupling in the first sub light conduction element 2011 is inclined in a different direction than the light out-coupling in the second sub light conduction element 2012.

For example, fig. 11 is a schematic view of a partial structure of a backlight in another example according to an embodiment of the present disclosure. As shown in fig. 11, the light splitting element 300 is configured to split the light emitted from the light source unit 100 to the light guide member into a plurality of light beams having different wavelengths. For example, the light splitting element 300 may include a light splitting prism, a light splitting grating, and the like, which may function as an element for separating light rays of different wavelengths.

For example, as shown in fig. 11, the plurality of sub-beams includes first color light 1003 and second color light 1004 with different wavelengths, the plurality of sub-light conductive elements 201 includes a first sub-light conductive element 2011 and a second sub-light conductive element 2012, the first color light 1003 is configured to enter the first sub-light conductive element 2011 and be reflected out of the first sub-light conductive element 2011 by an array of light out-couplers located in the first sub-light conductive element 2011, the second color light 1004 is configured to enter the second sub-light conductive element 2012, and be reflected out of the second sub-light conductive element 2012 by an array of light out-couplers located in the second sub-light conductive element 2012.

The embodiment of the disclosure is beneficial to the total reflection propagation regulation and control of the light rays with different colors by enabling the light rays with different colors to enter different sub light conduction elements, so that the utilization rate of the light rays is improved.

For example, the light out-couplers of the first sub light conductive elements 2011 are configured to be more reflective of the first color light 1003 than the second color light 1004, and the light out-couplers of the second sub light conductive elements 2012 are configured to be more reflective of the second color light 1004 than the first color light 1003. The embodiment of the disclosure can improve the utilization rate of light rays incident into the corresponding sub light conduction elements by regulating and controlling the reflectivity and the transmissivity of the light outcoupling parts in different sub light conduction elements.

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 disclosed embodiments are not limited thereto and the first color light and the second color light may be interchanged.

For example, fig. 12 is a schematic view of a partial structure of a backlight in another example according to an embodiment of the present disclosure. As shown in fig. 12, the plurality of sub-beams further includes third color light 1005, the third color light 1005 configured to enter one of the first sub-light conductive element 2011 and the second sub-light conductive element 2012. For example, as shown in fig. 12, the first color light 1003 and the third color light 1005 enter the first sub light conductive element 2011, and the second color light 1004 enters the second sub light conductive element 2012. The embodiments of the present disclosure are not limited thereto, and the third color light may also enter the same sub light-transmitting element as the second color light.

In the embodiment of the disclosure, two lights with different colors enter the same sub-light conduction element, so that the manufacturing cost of the light conduction element can be reduced, and the thickness of the backlight source can be reduced.

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

In the embodiment of the disclosure, two color lights with similar wavelengths enter the same sub-light-conducting element, so that the adjustment of the light-out-coupling element array in the sub-light-conducting element can be facilitated, and the cost can be reduced.

For example, fig. 13 is a schematic partial structure diagram of a backlight in another example according to an embodiment of the present disclosure. The example shown in fig. 13 is different from the example shown in fig. 12 in that a plurality of light rays of different colors are arranged so as to enter a plurality of sub light-transmitting elements one by one. As shown in fig. 13, the plurality of sub-beams further includes third color light 1005, the plurality of sub-light transmitting elements 201 further includes a third sub-light transmitting element 2013, the third color light 1005 is configured to enter the third sub-light transmitting element 2013 and be reflected off the third sub-light transmitting element 2013 by an array of light out-couplers located in the third sub-light transmitting element 2013. The embodiment of the disclosure can further improve the utilization rate of light rays by enabling the light rays with different colors to enter the different sub-light conduction elements one by one.

For example, as shown in fig. 13, the light out-coupler of the first sub light conductive element 2011 is configured to have a reflectivity for the first color light 1003 that is greater than the reflectivities for the second and

third color lights

1004, 1005 of the second sub light conductive element 2012 is configured to have a reflectivity for the second color light 1004 that is greater than the reflectivities for the first and

third color lights

1003, 1005, and the light out-coupler of the third sub light conductive element 2013 is configured to have a reflectivity for the third color light 1005 that is greater than the reflectivities for the first and

second color lights

1003, 1004. The embodiment of the disclosure can improve the utilization rate of light rays incident into the corresponding sub light conduction elements by regulating and controlling the reflectivity and the transmissivity of the light outcoupling parts in different sub light conduction elements.

For example, as shown in fig. 13, the refractive index of the waveguide medium of the first sub light conduction element 2011, the refractive index of the waveguide medium of the second sub light conduction element 2012, and the refractive index of the waveguide medium of the third sub light conduction element 2013 may be different and each set to accommodate the refractive index of the light entering the corresponding sub light conduction element. For example, the first color light 1003, the second color light 1004, and the third color light 1005 are blue light, red light, and green light, respectively, for example, three kinds of light are coupled into the same light conducting element, the light with different wavelengths propagates in the same medium, the medium has different refractive indexes for various light, generally, the total reflection angles of the light with the three wavelengths are different (for example, the critical angle for total reflection of red light is greater than the critical angle for total reflection of blue light), and the angle set by the light out-coupling element also needs to consider the light propagating at the three angles, so the efficiency is low; if the total reflection angles of the three light rays are close, the medium needs to be regulated and controlled to have different refractive indexes. In summary, various light rays can be separated, and each sub light conduction element can select a medium and a corresponding light out-coupling element, which can transmit the corresponding light rays as far as possible under the total reflection condition, so that the light utilization rate can be improved.

For example, the embodiments of the present disclosure are not limited to the plurality of sub-beams being sub-beams with different polarization directions or wavelengths, and each of the plurality of sub-beams may also be sub-beams with the same property, for example, the light splitting element is only configured to split one beam emitted from the light source portion into the plurality of sub-beams with the same property, and the plurality of sub-beams are configured to enter the plurality of sub-light conducting elements one by one. For in getting into a light conduction component with a bundle of light that light source portion jetted out, this disclosed embodiment divides into a plurality of light through a bundle of light with light source portion jetted out, and gets into different sub light conduction component respectively, can improve the utilization ratio of light, also can promote the homogeneity of the light of coupling out. When the sub-beams in the sub-beams have the same property, the sub-light-conducting elements may or may not overlap in a direction perpendicular to the display surface of the display panel.

For example, the light guiding element includes a plurality of sub light guiding elements, whether 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 sub light guiding elements, the plurality of light out-coupling members are uniformly arranged and the reflectivity gradually increases along the direction in which the light is totally reflected and propagated in the waveguide medium.

For example, the light-transmitting member includes a plurality of sub light-transmitting members, whether 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 sub light-transmitting members, an arrangement density of the plurality of light out-coupling members gradually increases in a direction in which light is propagated by total reflection in the waveguide medium.

In research, the inventors of the present application also found that: two polaroids with different light transmission directions are arranged on two sides of a liquid crystal layer of the liquid crystal display device, one polaroid is arranged between the liquid crystal layer and a backlight source, and only light rays with specific polarization states can pass through the polaroid between the liquid crystal layer and the backlight source to enter the liquid crystal display panel and are utilized to form images. For example, when the light emitted from the backlight is unpolarized light, only 50% of the light emitted from the backlight can be utilized by the liquid crystal layer, and the rest of the light is wasted or absorbed by the liquid crystal layer to generate heat, which results in a problem of low light utilization rate.

Fig. 14 is a schematic view of a partial structure of a backlight according to an example of another embodiment of the present disclosure. The backlight in this embodiment may also be referred to as a light source device, and may be applied to a display device together with a display panel or used alone, which is not limited in this disclosure. For example, the light source device in this embodiment may be disposed on the back side of the transmissive display panel, or may be disposed on the display side of the reflective display panel to provide light to the display panel.

As shown in fig. 14, the light source device includes: a light source unit 100, wherein light emitted by the light source unit 100 includes first polarized light 100-1 and second polarized light 100-2 with different polarization states; the light-transmitting element 200 includes a light out-coupling portion 240. The light source unit 100 is configured to make the light emitted therefrom reflectively propagate in the light transmitting element 200 after entering the light transmitting element 200, and the light out-coupling unit 240 is configured to out-couple the light reflectively propagating in the light transmitting element 200. For example, the reflective propagation includes at least one of total reflection propagation and specular reflection propagation. For example, the light out-coupling portion 240 includes a first light out-coupling portion 241 and a second light out-coupling portion 242, the first light out-coupling portion 241 being configured to out-couple the first polarized light 100-1 entering the light guide element 200; the light source device further comprises a polarization conversion structure 400, the polarization conversion structure 400 being configured to convert the second polarized light 100-2 after entering the light conductive element 200 into the first polarized light 100-1. The second light outcoupling portion 242 is configured to: after the polarization conversion structure 400 converts the second polarized light 100-2 entering the light conduction element 200 into the first polarized light 100-1, the converted first polarized light 100-1 is coupled out; or the second light outcoupling portion 242 is configured to: the second polarized light 100-2 entering the light conduction element 200 is coupled out 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.

As shown in fig. 14, the backlight includes a light source section 100 and a light conductive member 200. The light emitted from the light source unit 100 includes first polarized light 100-1 and second polarized light 100-2 having different polarization states. The light guide member 200 includes a waveguide medium 210 and a light out-coupling part 240, wherein light emitted from the light source part 100 is configured to enter the waveguide medium 210 and propagate through the waveguide medium 210 by total reflection, and the light out-coupling part 240 is configured to out-couple light propagating through the waveguide medium 210 by total reflection to a predetermined region 40.

For example, as shown in fig. 14, after polarized light beams with different polarization states emitted from the light source unit 100 pass through the light splitting structure, a first polarized light beam 1001 and a second polarized light beam 1002 can be obtained, respectively, and the polarization states of the first polarized light beam 1001 and the second polarized light beam 1002 are different.

For example, the first light out-coupling portion 241 is configured to out-couple the first polarized light beam 1001 entering the light conductive element 200 to the predetermined region 40. As shown in fig. 14, the backlight further includes a polarization conversion structure 400, and the polarization conversion structure 400 is configured to convert a second polarized light beam 1002 entering the light guide member 200 into a first polarized light beam 1001'. The second light out-coupling part 242 is configured to out-couple the converted first polarized light beam 1001' to the predetermined area 40, or out-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' and then emit the first polarized light beam 1001' to the predetermined area 40.

The polarization conversion structure provided in the backlight can convert unpolarized light emitted from the light source section into polarized light having a specific polarization state, and the polarized light can be utilized by the liquid crystal layer through the polarizing plate between the liquid crystal layer and the backlight to improve the utilization rate of light.

For example, in the example shown in fig. 14, the second polarized light beam 1002 coupled out from the second light out-coupling portion 242 is converted into the first polarized light beam 1001 'after passing through the polarization conversion structure 400, and the converted first polarized light beam 1001' is emitted to the predetermined region 40 together with the first polarized light beam 1001 coupled out from the first light out-coupling portion 241.

For example, the predetermined area 40 may refer to a certain area between the backlight and the display panel, but is not limited thereto, and the predetermined area may be any area located at the light emitting side of the backlight.

For example, the light source unit 100 in the present embodiment may have the same features as the light source unit 100 in the embodiment shown in fig. 1A to 13, and is not described herein again. The waveguide medium 210 in this embodiment may have the same features as the waveguide medium 210 in the embodiment shown in fig. 1A to 13, and is not described herein again.

For example, the light incoupling portion may be provided or not provided in the present embodiment. For example, the light incoupling portion provided in this embodiment may have the same or similar features as the light incoupling portion provided in the embodiment shown in fig. 1A to 13, and details are not repeated here.

For example, the light emitted from the light source 100 may be unpolarized light including the first polarized light beam 1001 and the 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 kinds of linearly polarized light with perpendicular polarization directions, such as S-polarized light and P-polarized light. The embodiments of the present disclosure are not limited thereto, and the first polarized light and the second polarized light may be two kinds of circularly polarized light or elliptically polarized light with opposite rotation directions. For example, the light emitted from the light source unit is not limited to two polarization states, but may include three or more polarization states.

For example, the first polarized light beam 1001 emitted from the first light outcoupling portion 241 does not change its characteristic in the process of being incident on the predetermined region 40. For example, the converted first polarized light beam 1001' has the same characteristics as the first polarized light beam 1001 of the light emitted from the light source unit 100, for example, is polarized light having the same polarization state. For example, the second polarized light beam 1002 emitted from the second light out-coupling portion 242 is changed in polarization direction by the polarization conversion structure 400 in the process of being incident on the predetermined region 40.

For example, some embodiments of the present disclosure are not limited to that the light entering the light conducting element from the light source portion propagates in the light conducting element by total reflection, for example, the light emitted from the light source portion may also propagate in the light out-coupling member by non-total reflection, for example, may propagate along a straight line.

For example, "total reflection propagation" in the embodiments of the present disclosure may mean that a reflection angle at which light (e.g., light rays having a large partial divergence angle and satisfying a total reflection condition) is reflected on an interface between the light-conducting element and air (or other medium) is not less than a critical angle of total reflection. For example, light incident on the light-conducting element propagates mostly by total reflection. For example, a portion of the light propagating in the light-conducting element may continue to propagate with total reflection, and another portion may not fully reflect, e.g., propagate in a straight line, or reflect and propagate in the light-conducting element with non-total reflection (e.g., specular reflection).

For example, "non-total reflection propagation" in embodiments of the present disclosure may refer to propagation of light in the light-conducting element in a manner other than total reflection, e.g., light may propagate within the light-conducting element and not be reflected (e.g., not be reflected at the interface between the medium and air); alternatively, the light may be reflected and propagated in a non-total reflection manner, for example, it may not satisfy a total reflection condition, for example, a reflection angle at which reflection occurs at an interface between a waveguide medium of the light guide member and air (or other medium) is smaller than a critical angle of total reflection, and it may be considered that the light is propagated in a medium with no or little total reflection.

Fig. 15 is a schematic view of a partial structure of a backlight according to an example of another embodiment of the present disclosure. As shown in fig. 15, the backlight further includes a light splitting element 300 configured to split light emitted from the light source section 100 toward the light guide member 200. For example, the light splitting element 300 may be located between the light source part 100 and the light conduction element 200, and configured to split the light emitted from the light source part 100 to the light conduction element 200 into a first polarized light beam 1001 and a second polarized light beam 1002.

For example, the light source section 100 emits unpolarized light, the spectroscopic element 300 includes a polarization spectroscopic element 310, and the polarization spectroscopic element 310 is configured to reflect one of the first polarized light and the second polarized light and transmit the other of the first polarized light and the second polarized light; the light splitting element 300 further comprises a reflective element 320, the reflective element 320 being configured to reflect one of the first polarized light and the second polarized light.

For example, the polarization splitting element 310 is configured to split unpolarized light emitted from the light source section 100 toward the light transmissive element 200 into a first polarized light beam 1001 and a second polarized light beam 1002 before the light is incident on the light transmissive element 200.

For example, as shown in fig. 15, the light conductive element 200 includes a first sub-element 2001 and a second sub-element 2002, and the first sub-element 2001 is provided therein with a first light out-coupling portion 241. The first polarized light beam 1001 is configured to enter the first sub-element 2001 and is coupled out to the predetermined region 40 by the first light out-coupling portion 241, for example, the first polarized light beam 1001 output by the first light out-coupling portion 241 is directly output, for example, collimated output light. For example, the second polarized light beam 1002 described above is configured to enter the second subelement 2002.

For example, as shown in fig. 15, the second sub-element 2002 includes a second light out-coupling part 242, and the polarization conversion structure 400 is configured to convert the second polarized light out-coupled from the second light out-coupling part 242 into the first polarized light. The first sub-element 2001 comprises a light exit surface, the first sub-element 2001 and the second sub-element 2002 overlap in a direction perpendicular to the light exit surface, and the polarization conversion structure 400 is located between the first sub-element 2001 and the second sub-element 2002; or the first sub-element 2001 and the second sub-element 2002 do not overlap in a direction perpendicular to the light exit surface.

For example, as shown in fig. 15, the second sub-element 2002 is provided with a second light out-coupling part 242, and the polarization conversion structure 400 is disposed on the light-emitting side of the second light out-coupling part 242 to convert the second polarized light beam 1002 coupled out from the second light out-coupling part 242 into the first polarized light beam 1001'. For example, the first sub-element and the second sub-element shown in fig. 15 may be provided with light out-coupling portions, and may have the same structure as the sub light conduction element described in fig. 9 or a different structure.

For example, fig. 15 schematically shows the first sub-element and the second sub-element as separate structures, but is not limited thereto, and the first sub-element and the second sub-element may also be integrated structures. For example, the first sub-element and the second sub-element may be connected by a connection portion on a side away from the light source portion, which is not limited in the embodiments of the present disclosure and may be arranged according to actual needs. The above "the first sub-element and the second sub-element may also be an integrated structure" may mean that the first sub-element and the second sub-element are made of the same material through a single process, or that the first sub-element and the second sub-element are connected together by a fixing method such as adhesion.

For example, as shown in fig. 15, the first sub-element 2001 includes a light emitting surface 001, the first sub-element 2001 and the second sub-element 2002 overlap in a direction perpendicular to the light emitting surface 001 (e.g., a 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 overlap may comprise a complete overlap and a partial overlap, for example a complete overlap or a partial overlap of the orthographic projections of the first sub-element and the second sub-element on a plane parallel to the light exit surface. Fig. 15 schematically shows that the first subelement and the second subelement completely overlap in the Y-direction.

For example, as shown in fig. 15, when the first sub-element 2001 and the second sub-element 2002 are overlapped in the Y direction, the converted first polarized light beam 1001' is processed by the first sub-element 2001 and then directed to the predetermined region 40. For example, the converted first polarized light beam 1001' may exit after passing through the first light out-coupling portion 241, or may exit without passing through the first light out-coupling portion 241, which is not limited in the embodiment of the present disclosure.

According to some embodiments of the present disclosure, the first sub-element and the second sub-element are overlapped, so that the brightness of the backlight source can be improved, and the uniformity of light can be improved.

For example, as shown in fig. 15, the polarization splitting element 310 is configured to transmit the second polarized light beam 1002 of the light emitted from the light source section 100 to the second sub-element 2002, and reflect the first polarized light beam 1001 of the light to the first sub-element 2001. The polarization splitting element in this embodiment may have the same features as the polarization splitting element shown in fig. 9, and is not described herein again.

For example, as shown in fig. 15, the light splitting element 300 further includes a reflecting element 320, the reflecting element 320 is located on a side of the polarization light splitting element 310 away from the light conducting element 200, and is configured to reflect the first polarized light beam 1001 and propagate the reflected first polarized light beam into the first sub-element 2001. The reflection element in this embodiment may have the same features as the reflection element shown in fig. 9, and is not described herein again.

For example, as shown in fig. 15, the case where the second polarized light is P-polarized light and the first polarized light is S-polarized light is taken as an example, and as shown in fig. 15, after the unpolarized light emitted from the light source unit 100 is processed by the polarization splitting element 310 having the polarization splitting function, the transmitted light includes P-polarized light and the reflected light includes S-polarized light (or vice versa). The transmitted P-polarized light enters the second sub-element 2002, and the reflected S-polarized light is reflected by the reflective element 320 and propagates to the first sub-element 2001. The S polarized light and the P polarized light are coupled out by the light out-coupling portions in the respective sub light conduction elements, for example, the S polarized light is directly coupled out by the first light out-coupling portion 241, and the P polarized light is coupled out by the second light out-coupling portion 242, then converted into the S polarized light by the polarization conversion element 400, and then output by the first sub element 2001, so that the unpolarized light emitted by the light source portion is converted into the same polarized light.

For example, the polarization conversion element may be a 1/2 wave plate. The embodiments of the present disclosure are not limited thereto, and it may be possible to convert the second polarized light into the first polarized light.

For example, as shown in fig. 15, the first sub-element 2001 may be located on a side of the second sub-element 2002 away from the light source unit 100, so that the transmitted second polarized light enters the second sub-element and the reflected first polarized light enters the first sub-element, but is not limited thereto. The light source part can also be positioned between the first subelement and the second subelement, or positioned on one side of the first subelement far away from the second subelement, and can be arranged according to actual requirements.

Fig. 16 is an exemplary diagram of the backlight shown in fig. 15. As shown in fig. 16, the light outcoupling part 240 includes an array of light outcoupling elements 220, each light outcoupling element of the array of light outcoupling elements 220 is configured to reflect a part of the light propagating to the light outcoupling element and propagate the reflected light to a predetermined area, and another part is transmitted to the waveguide medium 210 to continue the total reflection propagation. The waveguide medium 210 includes a main surface, the light outcoupling member array 220 includes a plurality of light outcoupling members 221 arranged in a first direction, the first direction is parallel to the main surface, an included angle between the light outcoupling member 221 and the main surface is a first included angle, an included angle between a light ray totally reflected and propagated in the waveguide medium 210 and the main surface is a second included angle, and a difference between the first included angle and the second included angle is not more than 10 degrees. For example, the included angles of the light outcoupling members 221 and the main surface are all almost equal and are all first included angles; for example, the angle between the at least one light outcoupling member 221 and the main surface is a first angle. For example, the difference between the first included angle and the second included angle is not greater than 5 degrees. For example, the first included angle and the second included angle are equal, for example, the light totally reflected and propagated in the waveguide medium 210 is parallel to the light outcoupling member 221, so that the light is reflected only once in each light outcoupling member, for example, the light parallel to the light outcoupling member is prevented from being transmitted and reflected thereon, so as to improve the uniformity of the light and prevent stray light. Of course, the embodiment of the present disclosure is not limited thereto, an angle between the light outcoupling element and the light propagated by total reflection may also be greater than 5 degrees, and the leaked stray light may be reflected back by providing the reflection structure on the side of the light conduction element away from the display panel to improve uniformity of light emitted from the light conduction element.

For example, as shown in fig. 16, the light out-coupling piece array 220 in the first light out-coupling part 241 includes a plurality of first light out-coupling pieces 2211 arranged in the first direction, and the light out-coupling piece array 220 in the second light out-coupling part 242 includes a plurality of second light out-coupling pieces 2212 arranged in the first direction.

For example, as shown in fig. 16, an angle between the first polarized light beam 1001 transmitted to the first light out-coupling member 2211 and the first light out-coupling member 2211 when the first polarized light beam is totally reflected and propagates is a third angle, an angle between the second polarized light beam 1002 transmitted to the second light out-coupling member 2212 and the second light out-coupling member 2212 is a fourth angle, and a difference between the third angle and the fourth angle is not greater than 5 degrees. For example, if the third angle and the fourth angle are equal, the angle of the polarized light entering the sub-element may be adjusted according to the inclination angle of the light outcoupling member in each sub-element. For example, setting the angles between different sub-elements and corresponding polarized light to be the same can also facilitate the fabrication of the sub-elements and the adjustment of the incident light angle.

For example, as shown in fig. 16, 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 included angle between the first light out-coupling piece 2211 and the second light out-coupling piece 2212 may be not more than 5 degrees, for example, the first light out-coupling piece 2211 may be parallel to the second light out-coupling piece 2212, so as to facilitate the fabrication of the light transmission element.

For example, as shown in fig. 16, the included angles between the first and/or second light out-couplers 2211 and 2212 and the first direction may both be acute angles, or may both be obtuse angles. The direction indicated by the arrow in the X direction shown in fig. 16 is a first direction, and 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, so that the total reflection propagation direction of each polarized light is the same as the first direction, and the included angle between each light out-coupling member and the first direction may be an acute angle; when the total reflection propagation direction of each polarized light is opposite to the first direction, included angles between each light outcoupling member and the first direction may be obtuse angles. The angle of the light outcoupling member with the first direction is related to the direction of total reflection propagation of the polarized light.

For example, as shown in fig. 16, the first light out-coupling member 2211 is configured such that the reflectivity to the first polarized light beam 1001 is greater than the reflectivity to the second polarized light beam 1002, and the transmittance to the second polarized light beam 1002 is greater than the transmittance to the first polarized light beam 1001.

The arrangement of the light out-coupling members in the embodiments of the present disclosure may have the same features as the arrangement of the light out-coupling members in the example shown in fig. 9, and will not be described herein again.

For example, as shown in fig. 16, the light emitted from the second sub-element 2002 may be transmitted by the light out-coupling element array 220 in the first sub-element 2001, or may not pass through the light out-coupling element array 220 in the first sub-element 2001, which is not limited by the embodiment of the present disclosure. For example, when polarized light exiting the second sub-element is transmitted by the array of light outcoupling means in the first sub-light conductive element, the array of light outcoupling means in the first sub-element has a higher transmittance for polarized light exiting the second sub-element.

For example, the light outcoupling portion is not limited to the light outcoupling member array, for example, the light outcoupling portion may also be at least one of a surface grating, a volume grating, a blazed grating, a prism, a reflective structure, and an outgoing light mesh point, and the light is emitted from the light conduction element by destroying the total reflection condition of the light through at least one of reflection, refraction, and diffraction effects.

For example, fig. 17 is a schematic view of a partial structure of a backlight provided according to another example of another embodiment of the present disclosure. The example shown in fig. 17 is different from the example shown in fig. 15 in that the positional relationship of the first sub-element and the second sub-element shown in fig. 17 is different. As shown in fig. 17, 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 (e.g., may be right-to-right connected or have a certain distance) in a direction (e.g., Y direction) perpendicular to the light emitting surface, so that the thickness of the backlight source can be reduced, and the length of each sub-element can be set smaller to reduce the degree of weakening of the light intensity at the edge of the light conducting element.

For example, as shown in fig. 17, the first sub-element 2001 and the second sub-element 2002 are arranged in the first direction, and the light source section 100 may be located between the first sub-element 2001 and the second sub-element 2002, but is not limited thereto. For example, when the light source unit 100 is located between the first sub-element 2001 and the second sub-element 2002, the total reflection propagation directions of the first polarized light beam 1001 and the second polarized light beam 1002 are opposite, in this case, the light outcoupling member in the first sub-element 2001 is not parallel to the light outcoupling member in the second sub-element 2002, for example, one of the two forms an acute angle with the first direction, and the other forms an obtuse angle with the first direction, so as to realize the light outcoupling by the light outcoupling member.

For example, fig. 18 is a schematic view of a partial structure of a backlight provided according to another example of another embodiment of the present disclosure. The example shown in fig. 18 is different from the example shown in fig. 15 in the position of the second light outcoupling portion. As shown in fig. 18, the first light out-coupling portion 241 and the second light out-coupling portion 242 may both be located in the first sub-element 2001. In this example, the light incident on the light guide member is polarized light.

For example, as shown in fig. 18, the first sub-element 2001 includes a second light out-coupling portion 242, the first sub-element 2001 includes a light out-coupling portion, the first sub-element 2001 and the second sub-element 2002 overlap in a direction perpendicular to the light out-coupling portion, the polarization conversion structure 400 is located on the light in-side of the second light out-coupling portion 242, the second polarized light entering the second sub-element 2002 is propagated by total reflection in the second sub-element and converted into the first polarized light by the polarization conversion structure 400, and then the converted first polarized light is coupled out by the second light out-coupling portion 242.

For example, as shown in fig. 18, the second sub-element 2002 is provided with a reflection structure 500, the second polarized light totally reflected and propagated 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 reflection structure 500, and the polarization conversion structure may be provided in the light transmission element 200 or outside the light transmission element 200.

For example, the first light out-coupling portion 241 in this example may couple out the first polarized light beam 1001, and the second light out-coupling portion 242 may couple out the second polarized light beam 1002 in the same manner as in the examples shown in fig. 15 to 17, or in different manners. For example, the light splitting element 300 in this example may have the same features as the light splitting element in the example shown in fig. 15, and the description thereof is omitted here. For example, the waveguide medium in the light-conducting element of the present example may have the same features as the waveguide medium in the example shown in fig. 15, and will not be described again. For example, the first polarized light and the second polarized light in this example may have the same features as the first polarized light and the second polarized light in the example shown in fig. 15, and are not described again.

For example, as shown in fig. 18, the first sub-element 2001 includes a light exit surface, and the first sub-element 2001 and the second sub-element 2002 partially overlap or completely overlap in a direction (e.g., Y direction) perpendicular to the light exit surface. The polarization conversion structure 400 is located at the light incident side of the second light out-coupling part 242, and the second polarized light beam 1002 entering the second sub-element 2002 is configured to propagate through total reflection in the second sub-element 2002, and is out-coupled by the second light out-coupling part 242 after being converted by the polarization conversion structure 400.

In the embodiment of the present disclosure, by setting the second polarized light to propagate through total reflection in the second sub-element, the second polarized light may be more uniform, for example, the light and dark distribution of the second polarized light may be more uniform. In the embodiment of the present disclosure, the first light out-coupling portion and the second light out-coupling portion are disposed in the same sub-element, so that the manufacturing cost can be reduced, and the implementation is easy.

For example, as shown in fig. 18, the light incident side of the first light outcoupling part 241 is located at a side of the first light outcoupling part 241 away from the second light outcoupling part 242, and the light incident side of the second light outcoupling part 242 is located at a side of the second light outcoupling part 242 away from the first light outcoupling part 241.

For example, fig. 18 schematically shows that a space is provided between the first light outcoupling portion 241 and the second light outcoupling portion 242, but the space is not limited thereto, and the first light outcoupling portion and the second light outcoupling portion may not be provided therebetween to prevent a dark region where no light is emitted between the two light outcoupling portions. For example, the first light out-coupling portion and the second light out-coupling portion may also be arranged to overlap to improve the uniformity of the light extraction.

For example, fig. 18 schematically 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 thereto, and when the polarization conversion structure is located in the first sub-element, or between the first sub-element and the second sub-element, or the first sub-element and the second sub-element are integrated, the polarization conversion structure may be located in the first sub-element and the second sub-element, or located outside the first sub-element and the second sub-element, and the polarization conversion structure may be located on the light incident side of the second light coupler, for example, the second polarized light propagating in the second sub-element may be converted into the first polarized light by the polarization conversion structure, and the first polarized light may be coupled out by the second light coupler.

For example, the second sub-element 2002 may include other light out-coupling portions (for example, the second sub-element is a separate structure from the first sub-element), or may not include light out-coupling portions (for example, the first sub-element is an integrated structure with the second sub-element), and the second sub-element is mainly configured to make the second polarized light propagate therein by total reflection.

For example, fig. 18 schematically illustrates that the light incident side of the second light outcoupling part 242 in the first sub-element 2001 is provided with the third light incoupling part 233, and the third light incoupling part 233 may have the same characteristics as the first light incoupling part and the second light incoupling part in the above-described embodiments, but is not limited thereto, and the light incident side of the second light outcoupling part 242 in the first sub-element 2001 may not be provided with the light incoupling part.

For example, the second polarized light may be converted into the first polarized light after passing through the polarization conversion structure only once, and the polarization conversion structure may be a 1/2 wave plate, for example. Of course, the embodiments of the present disclosure 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 1/4 wave plate.

For example, as shown in fig. 18, the polarization conversion structure 400 is disposed in the second sub-element 2002, and the reflection structure 500 is further disposed in the second sub-element 2002 and located on a side of the polarization conversion structure 400 away from the light source unit 100, and the second polarized light beam 1002 totally reflected and propagated in the second sub-element 2002 is configured to pass through the polarization conversion structure 400 twice, and is reflected once by the reflection structure 500 to enter the first sub-element 2001.

Fig. 19 is an exemplary diagram of the backlight shown in fig. 18. As shown in fig. 19, taking the example that the second polarized light beam 1002 is P-polarized light and the first polarized light beam is S-polarized light, the unpolarized light beam emitted from the light source unit 100 is processed by the polarization splitting element 310 having a polarization splitting function, and then the P-polarized light is transmitted and the S-polarized light is reflected (or vice versa). The transmitted P-polarized light is coupled into the second sub-element 2002 by the second light incoupling portion 232, and propagates through total reflection in the waveguide medium of the second sub-element 2002 to the reflective structure 500 at the end surface, where the reflected light no longer satisfies the total reflection condition, and the reflected light leaves the second sub-element 2002. The reflective structure 500 here may be considered as a light outcoupling portion of the second sub-element 2002. Meanwhile, the light incident side of the reflection structure 500 is further provided with a polarization conversion structure 400, when the P-polarized light is reflected, the P-polarized light firstly passes through the polarization conversion structure 400, the reflected light also passes through the polarization conversion structure 400 again, and then leaves the second sub-element 2002, for example, the P-polarized light passes through the polarization conversion structure 400 twice and is converted into S-polarized light, and the converted S-polarized light enters the waveguide medium of the first sub-element 2001 through the third light incident portion 233, is totally reflected, is transmitted to the second light outcoupling portion 242, and is outcoupled from the first sub-element 2001.

For example, as shown in fig. 19, the first light out-coupling part 241 and the second light out-coupling part 242 may each include a light out-coupling member array 220, and each light out-coupling member 221 included in the light out-coupling member array 220 has an approximately equal angle with a light ray incident on a surface thereof. For example, the light outcoupling element array 220 in the first light outcoupling portion 241 includes a plurality of first light outcoupling elements 2211 arranged in the first direction, and the light outcoupling element array 220 in the second light outcoupling portion 242 includes a plurality of second light outcoupling elements 2212 arranged in the first direction. Since the total reflection propagation direction of the first polarized light beam 1001 incident to the first light outcoupling portion 241 is opposite to the total reflection propagation direction of the converted first polarized light beam 1001' incident to the second light outcoupling portion 242, the first light outcoupling piece 2211 is not parallel to the second light outcoupling piece 2212, for example, the inclination directions of the first light outcoupling piece 2211 and the second light outcoupling piece 2212 may be considered to be different, for example, an included angle between one of the first light outcoupling piece 2211 and the second light outcoupling piece 2212 and the first direction is an acute angle, and an included angle between the other one of the first light outcoupling piece 2211 and the second light outcoupling piece 2212 and the first direction is an obtuse angle.

For example, fig. 19 schematically shows that the first sub-element and the second sub-element are at least partially overlapped in the Y direction, but is not limited thereto, and the first sub-element and the second sub-element may not be overlapped in the Y direction.

For example, fig. 20 is a schematic view of a partial structure of a backlight provided according to still another example of another embodiment of the present disclosure. The example shown in fig. 20 is different from the example shown in fig. 14 in that light emitted from the light source section is unpolarized light when entering the light guide member.

As shown in fig. 20, the light conducting element 200 comprises a first sub-element 2001 and a second sub-element 2002, the first sub-element 2001 comprises the first light out-coupling portion 241, and the second sub-element 2002 comprises the second light out-coupling portion 242. For example, the first sub-element and the second sub-element shown in fig. 20 may be provided with light out-coupling portions, and may have the same structure as the sub light conduction element described in fig. 9 or a different structure.

As shown in fig. 20, the light source unit 100 is configured to make the light emitted therefrom enter the first sub-element 2001, and the first polarized light in the light is coupled out by the first light out-coupling unit 241, and the second polarized light in the light propagates to the polarization conversion structure 400 in the first sub-element 2001 to be converted into the first polarized light; the first polarized light converted by the polarization conversion structure 400 propagates to the second light out-coupling portion 242 in the second sub-element 2002 to be out-coupled by the second light out-coupling portion 242.

For example, the polarization converting structure is arranged between the first subelement and the second subelement; or the first subelement is provided with the polarization conversion structure, and the polarization conversion structure is positioned on one side of the first light out-coupling part away from the light incident side of the first subelement; 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.

As shown in fig. 20, the light-transmitting element 200 includes a first sub-element 2001 and a second sub-element 2002, the first sub-element 2001 is provided with a first light out-coupling portion 241, and the second sub-element 2002 is provided with a second light out-coupling portion 242. Unpolarized light emitted by the light source section 100 is configured to enter the first sub-element 2001, and a first polarized light beam 1001 of the light is coupled out by the first light out-coupling section 241, and a second polarized light beam 1002 of the light is configured to propagate in the first sub-element 2001 to the polarization conversion structure 400 to be converted into a first polarized light beam 1001'; the first polarized light beam 1001' converted by the polarization conversion structure 400 is configured to propagate in the second sub-element 2002 to the second light out-coupling part 242 to be out-coupled by the second light out-coupling part 242. First light outcoupling portion not only can play the effect of coupled light, can also carry out the beam split to the unpolarized light that light source portion got into, and from this, this disclosed embodiment carries out the polarization beam split through the unpolarized light that light source portion got into in the light conduction component light outcoupling portion that lies in, can omit beam splitting device's setting in order to save the volume of backlight.

For example, the first light out-coupling portion 241 in this example may couple out the first polarized light beam 1001, and the second light out-coupling portion 242 may couple out the second polarized light beam 1002 in the same manner as in the examples shown in fig. 15 to 17, or in different manners. For example, the waveguide medium in the light-conducting element of the present example may have the same features as the waveguide medium in the example shown in fig. 15, and will not be described again. For example, the first polarized light and the second polarized light in this example may have the same characteristics as the first polarized light and the second polarized light in the example shown in fig. 15, and are not described again here.

For example, as shown in fig. 20, the first light out-coupling portion 241 may have 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, taking the example that the first polarized light is S-polarized light and the second polarized light is P-polarized light as an example, as shown in fig. 20, the unpolarized light emitted from the light source unit 100 is not split before entering the light guide element 200, but directly enters the first sub-element 2001, the first light out-coupling unit 240 is an element having high reflectance for the S-polarized light and high transmittance for the P-polarized light, and the S-polarized light gradually leaves the first sub-element 2001 as the light propagates; the P-polarized light is transmitted continuously, and after passing through the polarization conversion element 400, the P-polarized light is converted into S-polarized light, and then enters the second sub-element 2002 for transmission, and is coupled out of the second sub-element 2002 by the second light out-coupling portion 242.

For example, as shown in fig. 20, the first sub-element 2001 comprises a light exit surface, and the first sub-element 2001 and the second sub-element 2002 at least partially overlap in a direction perpendicular to the light exit surface. However, the first and second subelements may also be arranged along the total reflection propagation direction of the light, for example along the X-direction. For example, the first sub-element and the second sub-element may not overlap in a direction perpendicular to the light exit surface, the first light out-coupling portion in the first sub-element may couple out the first polarized light and transmit the second polarized light, and the second light out-coupling portion in the second sub-element may couple out the converted first polarized light.

Fig. 21 is an exemplary diagram of the backlight shown in fig. 20. As shown in fig. 21, the first light outcoupling portion 241 and the second light outcoupling portion 242 may each include an array of light outcoupling members 220, and the included angles of each light outcoupling member 221 included in the array of light outcoupling members 220 and light rays incident to the surface thereof are approximately equal. For example, the light out-coupling piece array 220 in the first light out-coupling part 241 includes a plurality of first light out-coupling pieces 2211 arranged in the first direction, and the light out-coupling piece array 220 in the second light out-coupling part 242 includes a plurality of second light out-coupling pieces 2212 arranged in the first direction. Since the total reflection propagation direction of the first polarized light beam 1001 incident to the first light outcoupling portion 241 is opposite to the total reflection propagation direction of the converted first polarized light beam 1001' incident to the second light outcoupling portion 242, the first light outcoupling piece 2211 is not parallel to the second light outcoupling piece 2212, for example, the inclination directions of the first light outcoupling piece 2211 and the second light outcoupling piece 2212 may be considered to be different, for example, an included angle between one of the first light outcoupling piece 2211 and the second light outcoupling piece 2212 and the first direction is an acute angle, and an included angle between the other one of the first light outcoupling piece 2211 and the second light outcoupling piece 2212 and the first direction is an obtuse angle.

The embodiment of the present disclosure is not limited thereto, when the first sub-element and the second sub-element are arranged along the X direction, a total reflection propagation direction of the first polarized light incident to the first light out-coupling portion is the same as a total reflection propagation direction of the first polarized light after conversion incident to the second light out-coupling portion, and then the first light out-coupling member and the second light out-coupling member may be substantially parallel, for example, the inclination directions of the first light out-coupling member and the second light out-coupling member may be considered to be the same, for example, an included angle between the first light out-coupling member and the first direction and an included angle between the second light out-coupling member and the first direction may be an acute angle or an obtuse angle.

For example, the first light out-coupling member 2211 may be an element having a higher reflectivity for the first polarized light beam 1001 and a higher transmittance for the second polarized light beam 1002 to realize light splitting for unpolarized light. For example, the second light out-coupling element 2212 may be a light out-coupling element with non-polarization-selective characteristic, or may be an element with higher reflectivity for the first polarized light, which is not limited by the embodiment of the present disclosure.

For example, as shown in fig. 21, the light emitted from the light source section 100 is configured to propagate by total reflection in at least one of the first subelement 2001 and the second subelement 2002. For example, fig. 21 schematically shows that light rays may propagate in the first sub-element 2001 and the second sub-element 2002 by total reflection, but is not limited thereto, and light rays entering the first sub-element from the light source portion may also propagate in the first sub-element by non-total internal reflection, such as directly propagating along a straight line, and then output by transflective action of the light out-coupling member.

For example, the polarization conversion structure 400 may be disposed between the first subelement 2001 and the second subelement 2002. For example, the polarization conversion structure 400 may be disposed in the first sub-element 2001 on a side of the first light out-coupling portion 241 away from the light source portion 100. For example, the polarization conversion structure 400 may also be disposed in the second sub-element 2002 and located at the light incident side of the second light out-coupling part 242.

For example, fig. 21 schematically shows that the first sub-element and the second sub-element are an integrated structure, and the polarization conversion structure is located in the integrated structure and located on the light exit side of the first light outcoupling part and the light entrance side of the second light outcoupling part. The embodiment of the present disclosure is not limited thereto, and the polarization conversion structure may be located at a position other than the first sub-element and the second sub-element, and may be located at a light exit side of the first light out-coupling portion and a light entrance side of the second light out-coupling portion.

For example, as shown in fig. 21, the light-conducting element 200 further includes a reflective structure 500 located at the light-incident side of the polarization conversion structure 400, the reflective structure 500 being configured to change the propagation direction of a second polarized light beam 1002 so that it is incident on the polarization conversion structure 400.

For example, the polarization conversion structure 400 may be a 1/2 wave plate. The polarization conversion structure in this example may be the same as the polarization conversion structure in the examples shown in fig. 18 to 19, and will not be described again here.

Compared with the scheme that all the light rays emitted by the light source part are transmitted and output through the same waveguide medium, the embodiment of the disclosure adopts the scheme that the light rays emitted by the light source part are divided into different polarization states and then are transmitted and output through the waveguides respectively, so that the brightness uniformity of the output light rays can be further improved.

For example, fig. 22 is a schematic view of a partial structure of a backlight according to an example of yet another embodiment of the present disclosure. As shown in fig. 22, the backlight includes a light source 100 and a light conducting plate 2000, the light conducting plate 2000 includes a light homogenizing part 250 and a light conducting element 200, the light conducting element 200 includes a light emitting surface, and the light homogenizing part 250 and the light conducting element 200 are sequentially arranged, for example, stacked, in a direction perpendicular to the light emitting surface. The light source unit 100 is configured to make the emitted light enter the light-transmitting element 200 after being totally reflected multiple times in the dodging unit 250, and then exit from the light-exiting surface of the light-transmitting element 200. For example, the light incident to the light uniformizing part 250 enters the light guide member 200 after being homogenized by the light uniformizing part 250. For example, the light incident on the light uniformizing section 250 may be the light emitted by the light source section 100, for example, the light emitted by the light source section 100 may be directly incident on the light uniformizing section 250, or may be processed by other elements and then incident on the light uniformizing section 250.

For example, the number of times of the multiple total reflection is not less than 5 times. For example, the number of times of the multiple total reflection may be 5 to 20 times. For example, the number of times of the multiple total reflection may be 6 to 12 times. For example, the number of times of the multiple total reflection may be 6 to 8 times.

For example, the dodging portion 250 includes a light incident end and a light exiting end, and the light incident end and the light exiting end are arranged along the extending direction of the light exiting surface; the thickness of the light uniformizing portions 250 in a direction perpendicular to the light exit surface is not greater than the thickness of the light transmissive elements 200 in the arrangement direction. Therefore, the dodging portion can increase the total reflection times of the total reflection light rays by setting a smaller thickness.

For example, the light conducting element 200 includes a waveguide medium 210 and a light outcoupling portion 240. The light conduction element 200 further includes a light uniformizing part 250, and light incident to the light uniformizing part 250, for example, light of the light source part 100 reaches the light out-coupling part 240 after passing through the light uniformizing part 250, and the light entering the light conduction element 200 is configured to propagate with 8-11 total reflections in the light uniformizing part 250.

For example, the refractive index of the uniform light portion 250 is larger than the refractive index of the waveguide medium 210 in the light-transmitting member 200. By adjusting the refractive index of the uniform light section, the critical angle of total reflection of the light propagating in total reflection can be adjusted, and when the critical angle of total reflection is smaller, the total reflection times can be increased.

For example, the light-transmitting plate 2000 is a unitary structure. For example, the dodging portion 250 is integrated with the waveguide medium 210. For example, the smoothing section 250 may be located between the light out-coupling section 240 and the light source section 100. This disclosed embodiment sets up even light portion through the income light side at the light outcoupling portion of waveguide medium, can improve the homogeneity of the light before transmitting to the light outcoupling portion, for example export after earlier the light homogenization to obtain the even area light source light of light and shade.

The "the uniform light portion and the waveguide medium are integrated" may mean that the uniform light portion and the waveguide medium are formed of the same material by a single process, or that the uniform light portion and the waveguide medium are connected to each other by a fixing means such as adhesion. For example, the uniform light portion and the waveguide medium may be made of materials with the same refractive index, or may be made of materials with different refractive indexes, which is not limited in the embodiment of the disclosure.

For example, the dodging portion shown in fig. 22 may also be provided in any of the examples shown in fig. 1A to 21 to further improve the uniformity of the output light of the backlight. For example, the light outcoupling portion in the present embodiment may have the same features as the light outcoupling portion in any of the examples shown in fig. 1A to 21, and the description thereof is omitted. For example, the waveguide medium in this embodiment may have the same features as the waveguide medium in any one of the examples shown in fig. 1A to 21, and will not be described herein again. For example, the light source portion in this embodiment may have the same features as the light source portion in any one of the examples shown in fig. 1A to 21, and is not described herein again.

For example, as shown in fig. 22, the length of the light unifying part 250 in the X direction may be not less than the length of the light outcoupling element array as the light outcoupling part 240 in the X direction. The disclosed embodiment is not limited thereto, and the length of the light unifying part 250 in the X direction may be 1/3 to 2/3 of the length of the light outcoupling element array as the light outcoupling part 240 in the X direction.

For example, fig. 23 is a schematic cross-sectional structure diagram of the backlight shown in fig. 22. As shown in fig. 23, the light incoupling portion 230 may be provided or may not be provided in the present embodiment. For example, as shown in fig. 23, the light incoupling portion 230 provided in this embodiment may have the same features as the light incoupling portion provided in any one of the examples shown in fig. 1A to 21, and is not described herein again.

For example, as shown in fig. 23, the light uniformizing part 250 may be disposed between the light incoupling part 230 and the light outcoupling part 240 of the light conduction element 200, or may be disposed between the light incoupling part and the light source part, which is not limited in the embodiment of the present disclosure.

For example, as shown in fig. 23, the light emitted from the light source unit 100 first enters the light uniformizing unit 250 through the light incoupling unit 230, and is transmitted and gradually homogenized in the light uniformizing unit 250; the homogenized light beam is coupled out by a light coupling-out part (e.g. a light coupling-out member array) 240, for example, converted into a collimated and parallel light beam to be emitted.

For example, as shown in fig. 23, the dodging portion 250 may totally reflect the light entering the dodging portion for a plurality of times, for example, 8 to 11 times, so as to make the light beam distribution uniform, thereby achieving the dodging effect. The homogenized light continues to be transmitted to the light out-coupling portion 240 along a total reflection path, and is converted into collimated light to be emitted through the transmission and reflection action of the light out-coupling portion 240, so that collimated parallel light with uniform brightness can be formed. For example, the dodging portion is disposed before the light outcoupling portion.

For example, as shown in fig. 22 and 23, the light outcoupling portion 240 includes a plurality of light outcoupling sub-portions 2401 arrayed in a first direction (for example, X direction), and the light uniformizing portion 250 and the light outcoupling portion 240 are arrayed in the first direction. For example, the light unifying part 250 and the light outcoupling part 240 are arranged on a plane parallel to the XZ plane.

For example, fig. 24 is a schematic view of a partial structure of a backlight provided according to another example of yet another embodiment of the present disclosure. As shown in fig. 24, the light-transmitting element 200 includes a light-emitting surface 001, the light out-coupling portion 240 and the waveguide medium 210 may be overlapped with the light uniformizing portion 250 in a direction perpendicular to the light-emitting surface 001, a gap medium 260 is disposed between the waveguide medium 210 and the light uniformizing portion 250, and a refractive index of the waveguide medium 240 and a refractive index of the light uniformizing portion 250 may be both greater than a refractive index of the gap medium 260. This disclosed embodiment is through setting up optical coupling portion and waveguide medium homogeneous and even light portion overlap, can practice thrift the shared area of even light portion, and then improves the area of the play plain noodles of backlight in order to obtain even area source light.

For example, as shown in fig. 24, the light uniformizing part 250 may be located on a side of the light out-coupling part 240 away from the light out-coupling surface 001.

For example, the gap medium 260 may be air or other solid medium (e.g., optical cement) having a refractive index smaller than that of the uniform light portion 250 and the waveguide medium 210 so that light rays propagating in the uniform light portion and the waveguide medium satisfy a total reflection condition.

For example, the gap medium 260 may be a transparent medium or a non-transparent medium, which is not limited by the embodiment of the disclosure.

For example, as shown in fig. 24, the length of the light unifying part 250 in the X direction may be not less than the length of the light outcoupling element array as the light outcoupling part 240 in the X direction to achieve a better light unifying effect, and the embodiment of the present disclosure is not limited thereto, and the length of the light unifying part 250 in the X direction may be 1/3 to 2/3 of the length of the light outcoupling element array as the light outcoupling part 240 in the X direction.

For example, as shown in fig. 24, a connection portion 270 is further disposed between the light transmitting element 200 and the dodging portion 250, and the connection portion 270 connects the light incident end of the light transmitting element 200 and the light emergent end of the dodging portion 250, so that the light of the dodging portion 250 enters the light transmitting element 200 through the connection portion 270.

For example, as shown in fig. 24, the connection portion 270 includes a light adjusting portion 271, and the light adjusting portion 271 is configured to break a total reflection condition of the total reflection propagating light in the light uniformizing portion 250, so that the light transmitted in the light uniformizing portion 250 can enter the light conductive element 200.

For example, as shown in fig. 24, the connecting portion 270 further includes a reflective surface 272, and the reflective surface 272 is configured to reflect the light in the dodging portion 250 into the light-transmitting element 200. In the embodiment of the present disclosure, the connecting portion may include at least one of the light adjusting portion and the reflective surface, and fig. 24 schematically illustrates that the connecting portion includes the light adjusting portion and the reflective surface, but is not limited thereto, and the connecting portion may include only the light adjusting portion, or only the reflective surface.

For example, the connecting portion 270 is further disposed between the waveguide medium 210 and the dodging portion 250, and the connecting portion 270 connects the waveguide medium 240 and one end of the dodging portion 250 away from the light incident side of the dodging portion 250, so that the light of the dodging portion 250 enters the waveguide medium 210 from the connecting portion 270. For example, the connection portion 270 is located on a side of the gap medium 260 away from the light source portion 100. For example, the light source section 100 and the connection section 270 are located on both sides of the gap medium 260 in the X direction.

For example, as shown in fig. 24, the connection portion 270 is located on the side away from the light incident side of the light uniformizing portion 250. For example, the connection portion 270 and the light source portion 100 are respectively located on both sides of the light uniformizing portion 250. For example, the connection portion 270 and the light source portion 100 are respectively located on both sides of the waveguide medium 210. For example, the connection portion 270 is located on the light exit side of the uniform light portion 250 and on the light entrance side of the waveguide medium 210.

For example, as shown in fig. 24, the connection portion 270 includes a light adjusting portion 271, and the light adjusting portion 271 is configured to break a total reflection condition of the total reflection propagating light in the light uniformizing portion 250 so that the light transmitted in the light uniformizing portion 250 can enter the waveguide medium 210.

For example, the light adjusting part 271 may be an optical element having a different refractive index from the waveguide medium 210, such as an optical paste, which breaks the total reflection condition and allows light to enter a light out-coupling part (e.g., an array of light out-coupling members) located on the display panel-facing side of the light uniformizing part 250.

For example, the light adjusting portion 271 may be used as a light out-coupling portion of the light uniformizing portion 250 and a light in-coupling portion of the waveguide medium, and may also be used as a light out-coupling portion of the light uniformizing portion 250 only, or a light in-coupling portion of the waveguide medium only, which is not limited in the embodiments of the present disclosure.

For example, as shown in fig. 24, the connection portion 270 further includes a reflective surface 272, and the reflective surface 272 is configured to reflect the light emitted from the light unifying portion 250 toward the waveguide medium 210.

For example, as shown in fig. 24, the light entering the light uniformizing portion 250 is transmitted along a total reflection path in the light uniformizing portion 250 and transmitted to the light adjusting portion 271, the light adjusting portion 271 may destroy the total reflection condition of the light, for example, the light may be continuously transmitted to the reflection surface 272 and reflected, the reflected light is transmitted to the light outcoupling portion 340 (e.g., the light outcoupling element array), and then is outcoupled by the light outcoupling portion 340, for example, is converted into collimated and parallel light for exiting.

For example, as shown in fig. 22 to 24, the present disclosure further provides a light source device, the light source device includes a light conducting plate 2000 and a light source part 100, the light conducting plate 2000 includes a light homogenizing part 250 and a light conducting element 200, the light conducting element 250 includes a light emitting surface, and the light homogenizing part 250 and the light conducting element 200 are sequentially arranged in a direction perpendicular to the light emitting surface; the light source unit 100 is configured to make the emitted light enter the light-transmitting element 200 after being totally reflected multiple times in the dodging unit 250, and then exit from the light-exiting surface of the light-transmitting element 200. The light source device may be the backlight source in the above embodiments, and may be applied to a display device together with a display panel, but is not limited thereto, and may also be applied to other devices in combination with other structures.

For example, the display panel provided by the embodiment of the disclosure may be a liquid crystal display panel, such as a transmissive liquid crystal display panel or a reflective liquid crystal display panel, and may form an image by cooperating with light provided by a backlight source. For example, light provided by the backlight source passes through a liquid crystal display panel (e.g., a liquid crystal screen) and is converted into image light. The embodiments of the present disclosure are not limited thereto, and the display panel may also be an electrowetting panel or a liquid crystal on silicon display element, and any kind of display panel may be matched with the backlight provided by the embodiments of the present disclosure to form a display device with uniform, light and thin light emergent light.

For example, fig. 25 is a partial structural schematic diagram of a display device provided according to an example of yet another embodiment of the present disclosure. As shown in fig. 25, the display device further includes a light diffusing element 30, the light diffusing element 30 is configured to diffuse the light emitted from the light conducting element 200, for example, the light diffusing element 30 is configured to diffuse the light beam passing through the light diffusing element 30. The backlight in the embodiments of the present disclosure may be the backlight shown in any one of fig. 1A to 24.

For example, the light diffusing element 30 is located between the light transmitting element 200 and the display panel 10. For example, the light diffusing element 30 may also be disposed on the light emitting side of the display panel 10, and configured to diffuse the image light emitted from the display panel 10, and the light diffusing element 30 is disposed close to the display panel 10, for example, to improve the imaging effect.

For example, fig. 25 schematically shows that the number of the light diffusing elements is 1, but is not limited thereto, and may be plural and disposed at intervals from each other to further improve the dispersion effect of the light beam. The embodiments of the present disclosure schematically show that the light diffusion element is located on the back side of the display panel, but not limited thereto, and may also be located on the display surface side of the display panel. For example, the light diffusing element may be attached to a surface of the display panel.

For example, the light diffusing element 30 is configured to diffuse a light beam passing through the light diffusing element 30 but not or hardly change a principal ray (chip light or optical axis) of the light beam. For example, the "principal ray" may refer to the center line of the beam, and may also be considered the principal direction of propagation of the beam. For example, after passing through the light diffusion element 30, the incident light beam is diffused into a light beam having a spot with a specific size and shape along the propagation direction, for example, the energy distribution of the spot can be homogenized and non-uniform; for example, the size and shape of the spot may be controlled by the microstructure of the surface design of beam spreading structure 30. For example, the specific shape may include, but is not limited to, at least one of a line, a circle, an ellipse, a square, and a rectangle.

For example, the light diffusing element 30 may not distinguish between the front and back sides. For example, the spread angle and the spot size after the light beam is spread determine the brightness and the visible area of the final image, and the smaller the spread angle is, the higher the imaging brightness is, and the smaller the visible area is; and vice versa.

For example, the light diffusing element 30 includes at least one of a diffractive optical element and a scattering optical element.

For example, the light diffusing element 30 may be a low-cost scattering optical element, such as a light homogenizing sheet, a diffusing sheet, etc., and the light beam is scattered and slightly diffracted when passing through the scattering optical element, such as a light homogenizing sheet, but the scattering mainly plays a role, and the light beam forms a relatively large light spot after passing through the scattering optical element.

For example, the light diffusing element 30 may be a Diffractive Optical Element (DOE) that controls the diffusion effect relatively more precisely, such as a Beam Shaper (Beam Shaper). For example, the diffractive optical element plays a role of light expansion mainly by diffraction by designing a specific microstructure on the surface, and the size and shape of the light spot are controllable.

For example, fig. 26 is a partial structural schematic view of a display device provided according to another example of yet another embodiment of the present disclosure. As shown in fig. 26, the display device further includes: the light converging element 40 is configured to converge the light emitted from the light transmitting element 200 toward the display panel 10. For example, the light converging element 40 is located between the light conducting element 200 and the light diffusing element 30, and the backlight source in the embodiment of the disclosure may be the backlight source shown in any one of the examples in fig. 1A to fig. 24.

For example, as shown in fig. 26, the light converging element 40 is configured to perform direction control on the collimated light emitted from the light conducting element 200, so as to converge the light to a predetermined range, and further converge the light, thereby improving the light utilization rate. The predetermined range may be a point, such as a focal point of the convex lens, or a smaller area, and the light converging element is arranged to uniformly adjust the direction of the collimated light output by the light conducting element to the predetermined range, so as to improve the utilization rate of the light.

For example, the light converging element 40 may be a lens or a lens combination, such as at least one lens, e.g., a convex lens, a fresnel lens or a lens combination, etc., which is schematically illustrated in fig. 26 by way of example.

For example, as shown in fig. 26, the light converging element 40 may converge the collimated light output from the light transmitting element 200 to a certain extent, and the light diffusing element 30 may diffuse the converged light. The embodiment of the present disclosure can provide high light efficiency and also enlarge a visible range by the cooperation of the light converging element and the light diffusing element.

For example, as shown in fig. 26, in the embodiment of the present disclosure, the light converging element 40 can converge and orient almost all the light rays, so that the light rays can reach the eye box region 003 of the user, for example, the collimated light beams output by the light conduction element 200 are convenient to control to realize convenient adjustment of the direction of the light rays. For example, a region where the observer views the image, such as an eye box region (eyebox) 003, may be preset according to actual requirements, and the eye box region 003 refers to a region where the eyes of the observer are located and where the image displayed by the display device can be seen, and may be a planar region or a stereoscopic region, for example. For example, the eye box region 003 may be a region where both eyes of the observer are present and where an image displayed on the display device can be viewed.

For example, as shown in fig. 26, the light emitted from the light source 100 is converted into collimated light which is emitted uniformly by the light conduction element 200, the collimated light passes through the light converging element 40, and then is collected and falls into the center of the eye box region 003, and the light is further diffused by the light diffusing element 30, and the diffused light beam can cover the eye box region 003, for example, just cover the eye box region 003, so that high light efficiency can be achieved, and normal observation cannot be affected. Embodiments of the present disclosure are not so limited, and the diffused beam may also be larger than the eye box area, e.g., at least completely covering the eye box; for example, the embodiments of the present disclosure may be implemented by arranging the light diffusion element such that the diffused light beam just covers the eye box area, in which case the light efficiency of the display device may be considered to be the highest.

For example, fig. 27 is a partial structural schematic view of a display device provided according to another example of yet another embodiment of the present disclosure. The example shown in fig. 27 differs from the example shown in fig. 26 in the positional relationship of the light converging element and the light conducting element. As shown in FIG. 27, the light converging element 40 is a unitary structure with the light transmitting element 200. The embodiment of the disclosure can reduce the thickness of the display device and facilitate the installation by arranging the light converging element and the light conducting element into an integrated structure, and can prevent unnecessary reflection of light rays generated on the interface between air and the light conducting element and/or the light converging element, thereby reducing or avoiding light effect waste.

For example, as shown in fig. 27, a transparent medium layer 50 is provided between the light converging element 40 and the light conducting element 200, and the refractive index of the transparent medium layer 50 is smaller than that of the light conducting element 200 so as to satisfy the total reflection condition of the light rays propagating in the waveguide medium. For example, the thickness of the transparent dielectric layer may be small enough to satisfy the total reflection propagation condition when the light propagates in the waveguide medium.

For example, the transparent dielectric layer 50 may be a medium with high transmittance, such as transparent optical glue, which can not only realize the adhesion of the light converging element and the light conducting element, but also improve the transmittance of light.

For example, the light converging element 40 and the light conducting element 200 may be made of the same material or different materials, which is not limited by the embodiments of the present disclosure.

For example, fig. 28 is a partial structural schematic view of a display device provided according to still another example of still another embodiment of the present disclosure. The light conversion device may be applied to a display device in which light emitted from the backlight is unpolarized light or light emitted from the light source section toward the light guide member is unpolarized light, and the display panel is configured to generate image light using one of the first polarized light and the second polarized light. The backlight here may be a backlight that satisfies this condition in the above-described embodiment. The term "unpolarized light" as used herein means that light emitted from the light source unit may have a plurality of polarization characteristics at the same time but does not exhibit unique polarization characteristics, and for example, light emitted from the light source unit may be considered to be composed of two orthogonal polarization states, and unpolarized light emitted from the light source unit may be considered to be decomposed into two orthogonal polarization states. The polarized light that can be used by the display panel herein may be polarized light that can enter the display panel, or may be polarized light that is necessary when the display panel forms an image of a specific polarization state.

For example, the light conversion device may be disposed at a plurality of positions, for example, configured to process light emitted from the light source section and propagate the processed light to the light conductive member. For example, the light conversion device is configured to recover light emitted from the light source section and send the recovered light to the light-transmitting member, and/or recover light emitted from the light-transmitting member and send the recovered light to the display panel. For example, recycling light may be understood as converting some of the light that is not available.

For example, as shown in fig. 28, the liquid crystal display panel 10 may include an array substrate (not shown), a counter substrate (not shown), and a liquid crystal layer (not shown) between the array substrate and the counter 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 opposite substrate and a second polarizing layer 10-2 disposed on a side of the opposite substrate away from the array substrate. For example, the backlight 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.

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

For example, only light of a specific polarization state may be incident into the liquid crystal display panel through the first polarization layer 10-1 between the liquid crystal layer and the backlight 20, and be imaged. For example, when the light emitted from the backlight 20 is unpolarized light, at most 50% of the light emitted from the backlight 20 can be used by the image generating portion, and the rest of the light is wasted or absorbed by the liquid crystal layer to generate heat. In the embodiment of the disclosure, the light conversion device is disposed on the light incident side of the display panel, so that the unpolarized light emitted by the backlight source can be almost completely converted into light with a specific polarization state, which can be utilized by the display panel, and the utilization rate of the light emitted by the backlight source is effectively improved.

For example, as shown in fig. 28, the light conversion device 50 is located on the side of the display panel 10 facing the light guide member 200. Fig. 28 schematically shows that the light conversion device 50 is located between the light converging element 40 and the light conducting element 200, but the light conversion device is not limited to this, and may be located between the light conducting 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, and the light conversion device may be located on the light incident side of the display panel to make the light incident on the display panel in a specific polarization state.

For example, the light conversion device includes a beam splitting element 51 and a polarization conversion element 53. 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 light incident to the beam splitting element 51 into a first polarized light beam 101 and a second polarized light beam 102 having different polarization states. For example, the first polarized light beam 101 is configured to be directed to the display panel 10, and the second polarized light beam 102 is directed to the direction changing element 52. The direction change element 52 is configured to change the traveling direction of the light incident to the direction change element 52 to be directed toward the display panel 10. The polarization conversion element 53 is configured to convert polarized light that cannot be utilized by the display panel 10 of the first and second polarized light beams 101 and 102 into polarized light that can be utilized by the display panel 10 before reaching the display panel 10.

For example, as shown in fig. 28, the first polarized light beam 101 and the second polarized light beam 102 may both be linearly polarized light. For example, the display panel 10 includes a first polarization layer 10-1 on a side of the display panel 10 close to the light source portion 100, a polarization axis of the first polarization layer 10-1 is parallel to a polarization direction of the first polarized light beam 101 or the second polarized light beam 102, and the polarization conversion element 53 is configured to convert polarized light of the first polarized light beam 101 and the second polarized light beam 102, which has a polarization direction not parallel to the polarization axis, into polarized light having a polarization direction parallel to the polarization axis before reaching the display panel 10. Fig. 28 schematically shows that the polarization direction of the second polarized light beam 102 is parallel to the polarization axis of the first polarizing layer 10-1, but is not limited thereto, and may be that the polarization direction of the first polarized light is parallel to the polarization axis of the first polarizing layer.

For example, as shown in fig. 28, the backlight 20 emits unpolarized light, the display panel 10 may use S-polarized light (second polarized light beam 102), the beam splitting element 51 reflects the S-polarized light and transmits the P-polarized light (first polarized light beam 101), and the direction changing element 52 may reflect the S-polarized light. The S polarized light in the light emitted from the backlight 20 is reflected by the beam splitting element 51, the reflected S polarized light is reflected by the direction changing element 52 and then emitted to the display panel 10, the P polarized light in the light emitted from the backlight 20 is transmitted by the beam splitting element 51, and the transmitted P polarized light is converted into the S polarized light by the polarization conversion element 53, so that the non-polarized light emitted from the backlight can be converted into the S polarized light usable by the display panel.

For example, the beam splitting element 51 may have the effect of transmitting light of one characteristic and reflecting light of another characteristic, e.g., the beam splitting element 51 may have the property of transmitting light of one polarization and reflecting light of another polarization, which may be split using the transflective characteristics described above.

For example, the beam splitting element 51 may be a transflective film, which performs the beam splitting action by transmitting a portion of the light and reflecting another portion of the light. For example, the transflective film may transmit a first polarized light beam 101 of light emitted by the backlight 20 and reflect a second polarized light beam 102 of light emitted by the backlight 20.

For example, the transflective film may be an optical film having a polarizing transflective function, such as an optical film that can split an unpolarized light ray into two different polarized lights by transmission and reflection, such as an optical film that splits a light ray into two mutually perpendicular polarized lights; the optical film can be formed by combining a plurality of film layers with different refractive indexes according to a certain stacking sequence, and the thickness of each film layer is between 10 and 1000 nm; the material of the film layer can be selected from inorganic dielectric materials, such as metal oxides and metal nitrides; polymeric materials such as polypropylene, polyvinyl chloride or polyethylene may also be selected.

For example, the beam splitting element 51 may be a transparent substrate film-coated or film-attached element. For example, the beam splitting element 51 may be a substrate on which a transflective Film having characteristics of reflecting S-polarized light and transmitting P-polarized light, such as a Dual Brightness Enhancement Film (DBEF) or a prism Film (BEF), is plated or attached. The disclosed embodiments are not limited thereto, for example, the beam splitting element may also be an integral element.

For example, the direction change element 52 is configured to reflect the second polarized light beam 102 incident to the direction change element 52 and propagate the reflected second polarized light beam to the display panel 10.

For example, the direction changing element 52 may be a reflecting element for reflecting the second polarized light beam 102 emitted from the beam splitting element 51 and transmitting the reflected second polarized light beam to 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 directed from the direction change element 52 to the display panel 10 can be directly utilized by the display panel 10.

For example, the direction change member 52 may be a common reflective plate, such as a metallic or glass reflective plate; or a reflecting film with the characteristic of reflecting S polarized light is plated or adhered on the substrate. For example, the direction changing element 52 may have transflective characteristics, such as characteristics of reflecting S-polarized light and transmitting P-polarized light, similar to the transflective film included in the beam splitting element 51. This is not limited by the disclosed embodiment, and it is sufficient that the direction change element 52 can reflect S-polarized light.

For example, the polarization conversion element 53 may be a phase retardation film, and the light emitted from the phase retardation film toward the display panel 10 is the second polarized light beam 102 that can be utilized by the display panel 10 by rotating the polarization direction of the first polarized light beam 101 incident thereon by 90 degrees. For example, the polarization conversion element 53 may be a 1/2 wave plate.

For example, the polarization conversion element may be disposed adjacent to the beam splitting element. For example, a transparent substrate may be disposed between the beam splitting element and the polarization conversion element, and the beam splitting element and the polarization conversion element are respectively attached to two surfaces of the transparent substrate opposite to each other for convenience of arrangement. For example, the beam splitting element may also be directly attached to the surface of the polarization conversion element to achieve lightness and thinness of the image source.

For example, as shown in fig. 28, the polarization conversion element 53 is located on the side of the beam splitting element 51 away from the direction changing element 50.

For example, FIG. 28 schematically illustrates the beam splitting element and the direction changing element as being approximately parallel, and the resulting exiting and recovered light rays as approximately parallel collimated light rays. But not limited thereto, if the beam splitting element and the direction changing element are not parallel, the emergent light can be in a diffused or condensed state, which is suitable for some special application scenarios.

For example, the light conversion device processes the light emitted from the light conductive member and transmits the processed light to the display panel. For example, the light conversion device 50 is located on a side of the display panel 10 facing the light guide member 200. For example, the light conversion device includes a beam splitting element 51 and a polarization conversion element 53, the beam splitting element 51 splitting the light rays, the polarization conversion element 53 converting one of the light rays into light rays having substantially the same properties as the other (e.g., substantially the same polarization state).

For example, the light conversion device 50 may also include a polarization splitting element 310 and a polarization conversion structure 400, the polarization splitting element 310 splits the light into a first polarized light and a second polarized light, and the polarization conversion structure 400 converts one of the first polarized light and the second polarized light into a linear polarization state substantially the same as the other.

For example, the light conversion device 50 may also include a polarization beam splitter 310, a reflective element 320, and a polarization conversion structure 400, where the polarization beam splitter 310 splits light into first polarized light and second polarized light, the polarization conversion structure 400 converts one of the first polarized light and the second polarized light into a polarization state substantially the same as the other, and the reflective element 320 reflects and transmits one of the light to the display panel. For example, fig. 29 is a schematic view of a light conversion device in a display device provided according to still another example of still another embodiment of the present disclosure. The light conversion apparatus shown in fig. 29 is different from the light conversion apparatus shown in fig. 28 in the position of the polarization conversion element and the light of the polarization state that can be utilized by the display panel, and the characteristics of the beam splitting element 51, the direction changing element 52 and the polarization conversion element 53 in the light conversion apparatus can be the same as those of the elements shown in fig. 28, and are not repeated herein.

For example, fig. 30 is a schematic view of a light conversion device in a display device provided according to still another example of still another embodiment of the present disclosure. The light conversion device shown in fig. 30 is different from the light conversion device shown in fig. 28 in the position of the polarization conversion element and the light in the polarization state that can be utilized by the display panel, and the polarized light reflected by the direction changing element 52 is different, and the characteristics of the beam splitting element 51 and the polarization conversion element 53 in the light conversion device may be the same as those of the elements shown in fig. 28, and are not described again here.

For example, fig. 31 is a schematic view of a light conversion device in a display device provided according to still another example of still another embodiment of the present disclosure. The light conversion device shown in fig. 31 is different from the light conversion device shown in fig. 29 in that the light in the present example passes through the polarization conversion element 53 twice, whereas the light in the example shown in fig. 29 passes through the polarization conversion element 53 only once, and the polarized light reflected by the direction change element 52 is different. For example, as shown in fig. 31, 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 toward the direction changing element 52 into a third polarized light beam 103, the third polarized light beam 103 is reflected by the direction changing element 52 and is converted into a first polarized light beam 101 after passing through the polarization conversion element 53, and the converted first polarized light beam 101 is emitted to the display panel 10.

For example, the polarization conversion element 53 may be a phase retardation film, such as a quarter-wave plate, and the polarized light incident on the direction changing element 52 after passing through the phase retardation film may be no longer linearly polarized by converting the second polarized light beam 102, such as linearly polarized light, incident thereon into a third polarized light beam 103, such as circularly polarized light or elliptically polarized light. The third polarized light beam 103 incident on the direction change element 52 is changed in propagation direction by the direction change element 52 to propagate toward the display panel 10, and the third polarized light beam 103 before reaching the display panel 10 passes through the polarization conversion element 53 again to be converted into the first polarized light beam 101 that can be utilized by the display panel 10. For example, the characteristics of the beam splitting element 51 and the direction changing element 52 in the light conversion device in this example may be the same as those of the corresponding elements shown in fig. 28, and are not described again.

For example, in at least one embodiment of the present disclosure, a principal ray of a light ray transmitted through the light out-coupling element (e.g., the light out-coupling element 211) intersects with an extending direction of the light emitting area of the light conducting element, such as the propagation in fig. 1 can be regarded as a propagation path of the principal ray of the light ray, which intersects with the light emitting area (e.g., the light emitting surface 211); alternatively, the chief ray of the light transmitted through the light outcoupling element is along the extending direction of the light outgoing area of the light transmission element, and as shown in fig. 34, the chief ray of the light may be parallel to the light outgoing surface 211. For example, light rays propagate in the light-transmitting element 200 primarily along straight paths.

Fig. 32 is a schematic view of a partial structure of a head-up display according to another embodiment of the disclosure. Fig. 32 schematically illustrates that the head-up display includes the display device illustrated in fig. 26, but is not limited thereto, and may also include the display device illustrated in fig. 25 or any one of fig. 27 to 31, which is not limited thereto by the embodiment of the present disclosure.

As shown in fig. 32, the head-up display further includes a reflective imaging section 60 located on the light exit side of the display panel 10, and the reflective imaging section 60 is configured to reflect the light emitted from the display panel 10 and transmit the reflected light to the eye box region 003, and transmit ambient light. The user located in the eye box region 003 can view 004 the display panel 10 reflected by the reflective imaging section 60 and an environmental scene located on the side of the reflective imaging section 60 away from the eye box region 003. For example, when the image light emitted from the display panel 10 is incident on the reflective imaging section 60, and the light reflected by the reflective imaging section 60 is incident on the user, for example, the eye box region 003 where the eyes of the driver are located, the user can observe a virtual image formed outside the reflective imaging section, for example, without affecting the observation of the external environment by the user.

For example, the eye box region 003 is a planar region where both eyes of the user are located and an image displayed on the head-up display can be viewed. For example, when the eyes of the user are deviated from the center of the eye-box region by a certain distance, such as up and down, left and right, the eyes of the user still stay in the eye-box region, and the user can still see the image displayed on the head-up display.

For example, as shown in fig. 32, the reflective imaging portion 60 may be at least one of a Windshield (e.g., a Windshield, such as a front Windshield, a side Windshield, or a rear Windshield) and an imaging window of a motor vehicle, for example, when the reflective imaging portion 60 is a Windshield, a windshields head-up display (Windshield-HUD, W-HUD); for example, the reflective imaging section 60 corresponds to a combined head-up display (C-HUD) when it is an imaging window.

For example, as shown in fig. 32, the reflective imaging section 60 may be a planar plate material, and a virtual image is formed by specular reflection; and the imaging lens can also be in a curved surface shape, such as a windshield or a transparent imaging plate with curvature, and the like, and can provide a longer imaging distance and a magnifying effect.

Fig. 33 is an exemplary block diagram of a transportation device provided in accordance with another embodiment of the present disclosure. As shown in fig. 33, the transportation apparatus includes a head-up display provided in at least one embodiment of the present disclosure, or includes a display device provided in at least one embodiment of the present disclosure. For example, the windows of the traffic devices are multiplexed into the reflective imaging portion 60 of the heads-up display. For example, a front window (e.g., front windshield) of the traffic device is multiplexed as the reflective imaging portion 60 of the heads-up display.

For example, the vehicle may be a variety of suitable vehicles, such as a land vehicle, which may include various types of automobiles, or a water vehicle, such as a boat, or an air vehicle, such as an airplane, whose driving position sets a front window and onto which images are projected via an on-board display system.

It is noted that in the drawings used to describe embodiments of the present disclosure, the thickness of layers or regions are exaggerated or reduced for clarity, i.e., the drawings are not drawn to scale. Although the present disclosure has been described in detail hereinabove with respect to general illustrations and specific embodiments, it will be apparent to those skilled in the art that modifications or improvements may be made thereto based on the embodiments of the disclosure. Accordingly, such modifications and improvements are intended to be within the scope of this disclosure, as claimed.

The following points need to be explained: (1) In the drawings of the embodiments of the present disclosure, only the structures related to the embodiments of the present disclosure are referred to, and other structures may refer to general designs. (2) Features of the same embodiment and different embodiments of the disclosure may be combined with each other without conflict.

The above description is intended to be exemplary of the present disclosure, and not to limit the scope of the present disclosure, which is defined by the claims appended hereto.

Claims

1. A display device, comprising:

a display panel including a display surface and a back side opposite the display surface; and

a backlight source positioned at a back side of the display panel,

the backlight source comprises a light conduction element, the light conduction element comprises a light emitting area and a light out-coupling member array, the light out-coupling member array comprises a plurality of light out-coupling members, light incident to the light conduction element sequentially propagates to the light out-coupling members of the light out-coupling member array, one part of the light propagating to each light out-coupling member in a part of the light out-coupling members is reflected out of the light emitting area of the light conduction element by the light out-coupling members and then transmits through the display panel, and the other part of the light propagating to each light out-coupling member in the part of the light out-coupling members continues to propagate in the light conduction element after transmitting through the light out-coupling members;

wherein the last light outcoupling element in the direction of said sequential propagation of light rays comprises a reflective film comprising a selectively reflective film and/or a non-selectively reflective film; and/or the optical axis of the light rays transmitted through the light outcoupling elements is along the arrangement direction of the partial light outcoupling elements.

2. The display device of claim 1, wherein a gas is between the plurality of light outcoupling members; or, a transparent optical medium is arranged among the light outcoupling members.

3. A display device as claimed in claim 1, characterised in that the reflective film causes the last light outcoupling element to have the largest reflectivity among the plurality of light outcoupling elements, and/or the reflective film totally reflects all or selected light incident thereon within a tolerance range; and/or the presence of a gas in the gas,

the reflecting film is a plated reflecting film or a reflecting film which is arranged in an attaching way or a reflecting film which is arranged independently; and/or, in case the last light outcoupling element comprises the reflective film, the optical axis of the light rays passing through the light outcoupling element intersects the extension direction of the light exit area of the light conducting element.

4. The display device according to claim 1, wherein the backlight source includes a light-conducting plate including a light uniformizing section and the light-conducting member, and light incident to the light uniformizing section enters the light-conducting member after being homogenized by the light uniformizing section; and/or the presence of a gas in the gas,

the source light line of the backlight comprises a component of first polarized light and a component of second polarized light, the polarization states of the first polarized light and the second polarized light are different, and the emergent light emitted from the light-emitting side of the backlight is polarized light and comprises one of the first polarized light and the second polarized light; and/or the presence of a gas in the gas,

the display device further includes a light converging element and a light diffusing element, and the light conducting element, the light converging element, the light diffusing element, and the display panel are sequentially disposed.

5. The display device according to claim 4, wherein the light incident to the light uniformizing section enters the light conductive member after being reflected a plurality of times within the light uniformizing section,

the multiple reflection comprises at least one total reflection and/or at least one non-total reflection type reflection, and/or the light conduction plate is of an integrated structure.

6. The display device according to claim 4, wherein the backlight source further includes a light conversion device including a polarization splitting element configured to split the source light incident to the polarization splitting element into the first polarized light and the second polarized light, and a polarization conversion element configured to convert one of the first polarized light and the second polarized light into the other, the display panel being configured to generate image light with one of the first polarized light and the second polarized light;

wherein polarized light obtained after the polarization conversion element converts one of the first polarized light and the second polarized light into the other is incident to the light conduction element; alternatively, the first and second electrodes may be,

one of the first polarized light and the second polarized light is converted into the other by the polarization conversion element after entering the light conduction element.

7. The display device according to claim 6, wherein the backlight source further comprises a reflection element configured to reflect the first polarized light or the second polarized light obtained by the light splitting process of the polarization light splitting element;

one of the first polarized light and the second polarized light obtained by the light splitting processing is reflected by the reflection element and then converted by the polarization conversion element, or is reflected by the reflection element after being first converted by the polarization conversion element and then is second converted by the polarization conversion element.

8. The display device according to claim 6, wherein the light-transmitting member includes a plurality of sub light-transmitting members including a first sub light-transmitting member and a second sub light-transmitting member connected to or spaced apart from each other, the first sub light-transmitting member and the second sub light-transmitting member are disposed in a stacked manner along an arrangement direction of the backlight source and the display panel or disposed in sequence along a direction perpendicular to the arrangement direction of the backlight source and the display panel, and the polarization splitting member splits the light to obtain the first polarized light and the second polarized light, and the first polarized light and the second polarized light are incident on different sub light-transmitting members;

wherein, under the condition that the first sub light conduction element and the second sub light conduction element are stacked along the arrangement direction of the backlight source and the display panel, both the first sub light conduction element and the second sub light conduction element, into which the first polarized light and the second polarized light respectively enter, include the light out-coupling members arranged in sequence or one of them does not include the light out-coupling members arranged in sequence.

9. The display device according to claim 8, wherein, in a case where the first sub light conduction element and the second sub light conduction element are provided in a stack, wherein,

the first light emitting area of the first sub light conduction element and the second light emitting area of the second sub light conduction element are overlapped, and light emitted from one of the first light emitting area and the second light emitting area is transmitted to the other one of the first light emitting area and the second light emitting area or transmitted to the other one of the first light emitting area and the second light emitting area after passing through the polarization conversion element; or, the second sub light conduction element includes a light conduction region and a second light exit region which are sequentially arranged along the extending direction of the second sub light conduction element, polarized light in the second sub light conduction element is reflected and propagated by total reflection and/or non-total reflection in the light conduction region, and propagates into the first sub light conduction element after propagating into the second light exit region, and the light conduction region of the second sub light conduction element overlaps with the first light exit region of the first sub light conduction element.

10. The display device of claim 6, wherein the light converging element comprises at least one lens; and/or the light converging element and the light conduction element are of an integrated structure, a transparent medium layer is arranged between the light converging element and the light conduction element, and the refractive index of the transparent medium layer is smaller than that of the light conduction element.

11. The display device according to any one of claims 1 to 5,

the backlight source further comprises a light splitting element configured to split light incident to the light splitting element into a plurality of sub-beams, which respectively enter a plurality of sub-light-conducting elements included in the light-conducting element;

the plurality of sub light conduction elements are arranged in an overlapped mode in a direction perpendicular to the display surface of the display panel, and/or the plurality of sub light conduction elements are arranged in a direction parallel to the display surface;

the light splitting element is configured to split source light of the backlight source incident to the light splitting element to obtain different characteristic light, and the different characteristic light is incident to different sub light conduction elements;

the first characteristic light and the second characteristic light obtained through the light splitting processing are respectively first polarized light and second polarized light with different polarization states; alternatively, the first characteristic light and the second characteristic light obtained by the spectral processing are first color light and second color light having different wavelength distributions, respectively.

12. A display device as claimed in claim 11, wherein the light outcoupling means in a first sub-light-transmitting element of the light-transmitting elements has a reflectivity for the first characteristic light which is greater than the reflectivity for the second characteristic light, and the light outcoupling means in a second sub-light-transmitting element of the light-transmitting elements has a reflectivity for the second characteristic light which is greater than the reflectivity for the first characteristic light.

13. The display device according to any one of claims 1 to 10, wherein the reflectance of the light outcoupling elements arranged in sequence along the extension direction of the light outcoupling region in the light outcoupling element array gradually increases or gradually increases regionally in the propagation direction of the light; and/or the arrangement density of the light outcoupling elements arranged in sequence in the extending direction of the light outcoupling region in the light outcoupling element array gradually increases or gradually increases regionally; alternatively, the first and second liquid crystal display panels may be,

at least one light outcoupling element of the array of light outcoupling elements comprises a light-selective film, the light entering the light conducting element comprising a first light and a second light of different characteristics, the selective film being configured such that the reflectivity for the first light is greater than the reflectivity for the second light and/or the transmissivity for the second light is greater than the transmissivity for the first light.

14. A display device according to any one of claims 1-10, wherein the array of light outcoupling elements comprises a first set of light outcoupling elements and a second set of light outcoupling elements arranged in the direction of extension of the light outcoupling area, each set of light outcoupling elements comprising light outcoupling elements arranged in the direction of extension of the light outcoupling area, the direction of inclination of the light outcoupling elements of the first set of light outcoupling elements with respect to the light outcoupling area being non-parallel to the direction of inclination of the light outcoupling elements of the second set of light outcoupling elements with respect to the light outcoupling area;

wherein the backlight further comprises a light source section comprising a first light source section and a second light source section, the first light source section and the second light source section being located on respective sides of the light outcoupling array in the extension direction of the light outcoupling region, the first group of light outcoupling elements being configured to reflect light rays emitted by the first light source section that enter the light guiding element out of the light guiding element, and the second group of light outcoupling elements being configured to reflect light rays emitted by the second light source section that enter the light guiding element out of the light guiding element; or

Wherein the light source unit is located between the first light out-coupling group and the second light out-coupling group in the extending direction of the light exit region.

15. The display device according to any one of claims 1-10, wherein the backlight further comprises a light source shore, wherein,

at least some of the plurality of light outcouplers included in the light outcoupler array are sequentially arranged in a first direction and extend in a second direction intersecting the first direction, the light source section includes a plurality of sub light sources arranged in the second direction, and the plurality of sub light sources are configured to emit light rays entering the at least some of the light outcouplers; alternatively, the first and second electrodes may be,

the light-out piece array includes at least some light-out pieces among a plurality of light-out pieces arrange in proper order along the first direction and along with the crossing second direction of first direction extends, light source portion includes the sub light source, display device still includes the edge a plurality of portions that expand and restraint that the second direction was arranged, a plurality of portions that expand are restrainted are configured as with light that the sub light source sent is followed the second direction is expanded the beam, and the light after expanding the beam is configured as and is transmitted extremely the light-out piece array.

16. The display device of any one of claims 1-10, wherein the backlight is a side-entry backlight.

17. The display device according to any one of claims 1 to 10, wherein the selective reflection film comprises a polarizing reflection film comprising a polarizing transflective film and/or a polarizing absorption film; or

The selective reflection film includes a polarization reflection film including a polarization transflective film and/or a polarization absorption film, and a wavelength selective reflection film.

18. The display device according to claim 17, wherein a polarization state of polarized light incident on the polarizing reflective film coincides with a polarization state of outgoing light outgoing from a light outgoing side of the backlight.

19. A heads-up display, comprising:

the display device of any one of claims 1-18; and

and the reflective imaging part is configured to reflect the light rays emitted by the display device and then transmit the light rays to an observation area of the head-up display.

20. Traffic apparatus comprising a heads-up display according to claim 19 or a display device according to any of claims 1-18; wherein, where the traffic device comprises the heads-up display of claim 19, the reflective imaging portion of the heads-up display comprises at least one of a windshield or an imaging window of the traffic device.