CN215769261U - Light source device, display device, head-up display, and traffic equipment - Google Patents
Light source device, display device, head-up display, and traffic equipment Download PDFInfo
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- CN215769261U CN215769261U CN202120370346.6U CN202120370346U CN215769261U CN 215769261 U CN215769261 U CN 215769261U CN 202120370346 U CN202120370346 U CN 202120370346U CN 215769261 U CN215769261 U CN 215769261U
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Abstract
The embodiment of the utility model provides a light source device, a display device, a head-up display and traffic equipment. A light source device, comprising: a light source unit that emits light including first polarized light and second polarized light having different polarization states; the optical waveguide element includes a light outcoupling portion; and a polarization conversion structure. The light out-coupling portion 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 first polarized light entering the optical waveguide element; the polarization conversion structure is configured to convert the second polarized light after entering the optical waveguide element into the first polarized light. In the present disclosure, the polarization conversion structure may convert unpolarized light emitted from the light source section into polarized light having a specific polarization state, and the polarized light may 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.
Description
Technical Field
At least one embodiment of the present disclosure relates to a light source device, 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.
SUMMERY OF THE UTILITY MODEL
At least one embodiment of the present disclosure provides a light source device, a display device, a head-up display, and a transportation apparatus.
At least one embodiment of the present disclosure provides a light source device, including: a light source unit that emits light including first polarized light and second polarized light having different polarization states; an optical waveguide element including a light outcoupling portion. The light source part is configured to make the light emitted by the light source part propagate in the optical waveguide element in a reflection mode after entering the optical waveguide element, and the light out-coupling part is configured to couple out the light propagating in the optical waveguide element in the reflection mode; the light out-coupling comprises a first light out-coupling configured to couple out the first polarized light entering the optical waveguide element and a second light out-coupling; the light source device further includes a polarization conversion structure configured to convert the second polarized light after entering the optical waveguide element into first polarized light, the second light outcoupling portion being configured to: after the polarization conversion structure converts the second polarized light entering the optical waveguide element into first polarized light, coupling the converted first polarized light out; or the second light out-coupling part is configured to: coupling out the second polarized light entering the optical waveguide element to the polarization conversion structure such that the coupled out second polarized light is converted to the first polarized light by the polarization conversion structure.
At least one embodiment of the present disclosure provides a display device including: a display panel; and any light source device of the present disclosure configured to provide backlight to the display panel.
At least one embodiment of the present disclosure provides a head up display including: any display device of the present disclosure; and the reflection imaging part is positioned on the light emergent side of the display device and is configured to reflect the light emergent from the display device to the observation area of the head-up display.
At least one embodiment of the present disclosure provides a transportation device including any of the heads-up displays of the present disclosure.
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 of light rays exiting an array of transflective elements being non-perpendicular to a major surface of a 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 diagram 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 provided in accordance with yet 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.
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 similar terms 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.
In the research, the inventors of the present application 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.
The embodiment of the disclosure provides a light source device, a display device, a head-up display and traffic equipment. A light source device, comprising: a light source unit that emits light including first polarized light and second polarized light having different polarization states; an optical waveguide element including a light outcoupling portion. The light source part is configured to make the light emitted by the light source part propagate in the optical waveguide element in a reflection mode after entering the optical waveguide element, and the light out-coupling part is configured to couple out the light propagating in the optical waveguide element in the reflection mode; the light out-coupling comprises a first light out-coupling configured to couple out the first polarized light entering the optical waveguide element and a second light out-coupling; the light source device further includes a polarization conversion structure configured to convert the second polarized light after entering the optical waveguide element into first polarized light, the second light outcoupling portion being configured to: after the polarization conversion structure converts the second polarized light entering the optical waveguide element into first polarized light, coupling the converted first polarized light out; or the second light out-coupling part is configured to: coupling out the second polarized light entering the optical waveguide element to the polarization conversion structure such that the coupled out second polarized light is converted to the first polarized light by the polarization conversion structure. In the present disclosure, the polarization conversion structure may convert unpolarized light emitted from the light source section into polarized light having a specific polarization state, and the polarized light may 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.
The following describes a light source device, 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 passes through the display panel 10 and is 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.
As shown in fig. 1A, the backlight 20 includes a light source unit 100 and an optical waveguide element 200, the optical waveguide element 200 includes a light exit surface 211 and a transflective element array 220, and the transflective element array 220 includes a plurality of transflective elements 221. The light source unit 100 is configured such that light emitted therefrom enters the optical waveguide element 200, is totally reflected at least at the light exit surface 211 of the optical waveguide element 200 multiple times and sequentially propagates to the plurality of transflective elements 221 of the transflective element array 220, a part of the light propagating to each transflective element 221 of the transflective element array 220 is reflected by the transflective element 221 out of the light exit surface 211 of the optical waveguide element 200 and then passes through the display panel 10, and another part of the light propagating to each transflective element 221 of the transflective element array 220 passes through the transflective element 221 and then continues to propagate in the optical waveguide element 200.
In the embodiment of the disclosure, by arranging the optical waveguide element in the backlight, the thickness of the backlight and the occupied space in the display device can be reduced while the light-emitting brightness is uniform, so as to improve the display effect and the portability of the display device.
For example, as shown in fig. 1A, the optical waveguide element 200 further includes a waveguide medium 210, the light emitted from the light source unit 100 enters the waveguide medium 210 and propagates through the waveguide medium 210 by total reflection, a part of the light propagating through each transflective element 221 of the transflective element array 220 is reflected by the transflective element 221 out of the optical waveguide element 200, and the other part of the light continues to propagate through total reflection after being transmitted through the transflective element 221.
For example, the transflective element array 220 includes a plurality of transflective elements 221, and light rays propagating to each of the transflective elements 221 are transmitted and reflected on the transflective elements 221. For example, a part of the light incident on the surface of the transflective element 221 is reflected by the transflective element 221 out of the optical waveguide element 200, and another part of the light is transmitted by the transflective element 221 and then continuously propagates to the next transflective element 221 by total reflection, and transmission and reflection occur on the next transflective element 221, and the transmitted light continuously propagates to the one transflective element 221 farthest from the light source unit 100 by total reflection (for example, the light is transmitted by the plurality of transflective elements in sequence until the one transflective element farthest from the light source unit). For example, all or part of the light rays propagating to the one transflective element farthest from the light source part may be reflected by the transflective element, and the embodiments of the present disclosure are not limited thereto.
For example, as shown in fig. 1A, the light emitting surface 211 of the optical waveguide element 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 on the side of the optical waveguide element 200. In the embodiment of the present disclosure, the optical waveguide element is located below the display panel, and the light source unit is located on a side of the optical waveguide element, but the present disclosure is not limited thereto. For example, the display panel 10 includes a display surface for displaying images, and the light emitting surface of the optical waveguide element 200 is located on a side of the display panel 10 away from the display surface, for example, below the display panel 10, rather than on the side of the display panel 10; the light source unit 100 is located at a side of the light guide element 200, that is, the backlight 20 is a side-in type backlight.
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 rays emitted from the light source having a certain divergence angle into collimated light rays. 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, i.e., a light beam extending 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, the transflective element array 220 includes a plurality of transflective element arrays 220 in which at least some of the transflective elements 221 are sequentially arranged along a first direction and extend along a second direction intersecting the first direction. For example, the number of transflective elements 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 section 100 may include a plurality of sub light sources 101 arranged in the second direction, the plurality of sub light sources 101 being configured to emit light rays entering the at least partially transflective element 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, and the whole sub-light source does not need to be replaced like a strip-mounted light strip, so that the cost is 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 transflective element array 200 includes a plurality of transflective elements 220 extending along the second direction, the light source part 100 includes a plurality of beam expanding parts 102 arranged along the second direction and sub-light sources 101 located at one side of the plurality of beam expanding parts 102 in the second direction, the plurality of beam expanding parts 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 transflective 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 section of the light source is 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 transflective 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 expand in the second direction, and then is transmitted to the transflective 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 be another array of transflective elements, which is not limited by the embodiments of the present disclosure.
For example, the light source may introduce light into the optical waveguide device in a lateral approach manner, which may avoid further increasing the thickness of the backlight.
For example, when the backlight provided by the embodiment of the disclosure is applied to a display device which needs to have higher brightness, such as a head-up display, the backlight can be provided with higher brightness by using a light source (e.g., a lamp strip or a plurality of point light sources arranged in a linear manner) which emits a one-dimensional light beam, and the scheme is simple and easy to implement.
For example, fig. 4B is a schematic structural diagram of another backlight. The backlight of fig. 4B differs from the backlight of fig. 4A in that the expanded beam portion is located in the optical waveguide element.
For example, as shown in fig. 1A, the optical waveguide element 200 further includes a light incoupling part 230 located on a side of the transflective element array 220 facing the light source part 100, configured such that light entering the optical waveguide element 200 satisfies a total reflection condition to propagate in the waveguide medium 210 by total reflection. The embodiments of the present disclosure are not limited to the optical waveguide element including the light incoupling portion, for example, the optical waveguide 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 implement 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 coupler is not less than the critical angle arcsin of total reflection (n2/n1), 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 optical waveguide element 200 includes two first main surfaces 211 and second main surfaces 212 opposing each other, and the light incoupling portion 230 may be provided on the first main surface 211 and the second main surface 212, or may be provided on a side surface connecting the two main surfaces. For example, the two main surfaces of the optical waveguide element may also be referred to as the two main surfaces of the waveguide medium. For example, the array of transflective elements is located between the first major surface and the second major 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 optical waveguide element includes a plurality of sub optical waveguide elements, for example, the plurality of sub optical waveguide elements are arranged to overlap in a direction perpendicular to the first main surface, the upper surface of the sub optical waveguide element on the uppermost side is the first main surface, and the lower surface of the sub optical waveguide element on the lowermost side is the second main 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 transflective element 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 substrate, a ridge 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 transflective element array 220 includes a plurality of transflective elements 221 arranged along a total reflection propagation direction of light, which may refer to a direction of the whole (macroscopic) light propagation, such as the first direction (i.e., X direction) shown in fig. 1A, where the light entering the optical waveguide element 200 undergoes total internal reflection at both major surfaces of the waveguide medium 210, so that the light propagates to the transflective element array 220 along the X direction as a whole.
For example, as shown in fig. 1A to 3, the transflective element 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 transflective element 221, the light is reflected at the transflective element 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 transflective element 221, continues to be reflected and transmitted, the light reflected by the next transflective element 221 exits from the optical waveguide element 200, and the light transmitted by the next transflective element 221 continues to propagate along the total reflection path; and so on until the last transflective element 221.
For example, as shown in FIG. 1A, the transflective element 221 may be plated or otherwise disposed in the waveguide medium 210. For example, the waveguide medium 210 may be divided into a plurality of cylinders having a parallelogram in cross section, and the transflective elements 221 are disposed between the spliced cylinders, i.e., the medium between adjacent transflective elements 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, a transflective element 221 is sandwiched between adjacent waveguide sub-media, each waveguide sub-medium is configured to cause total internal reflection of light, and the transflective element is configured to couple a portion of light out of the optical waveguide element by reflecting a total reflection condition that destroys the portion of light.
For example, the embodiment of the disclosure is described with an example in which the plurality of transflective elements 221 in the transflective element array 220 are all parallel to each other, and the light exiting from the transflective element array is parallel light. However, the embodiments of the present disclosure are not limited thereto, and the plurality of transflective elements in the transflective element array may not be parallel, and the light emitted from the transflective element array may be adjusted to be convergent light or divergent light by adjusting an included angle between the plurality of transflective elements.
For example, as shown in fig. 1A, an included angle between each transflective element 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 the light beam at the light-emitting surface 211 is within a range of 60 ° to 120 °. 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 °. According to the embodiment of the disclosure, by setting the sum of the first included angle between the transflective element and the light-emitting surface and the critical angle of total reflection of the light when the light is totally reflected at the light-emitting surface, for the same path of light, the light can be reflected once in each transflective element, for example, the light parallel to or nearly parallel to the transflective element is prevented from being transmitted and reflected thereon, the uniformity of the light can be improved, and the generation of stray light is reduced or avoided.
For example, the included angle between each transflective element 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, that is, the light totally reflected and propagated in the waveguide medium 210 is parallel to the transflective element 221, for the same path of light, the light can be reflected once in each transflective element, for example, the light parallel to the transflective element is prevented from being transmitted and reflected thereon, the uniformity of the light can be improved, and the generation of stray light can 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 is different from the example shown in fig. 1A in that a reflection device 600 is disposed on a side of the optical waveguide element 200 away from the display panel 10, and an angle between the transflective element 221 and the light propagated by total reflection may not be limited, for example, may not be parallel, for example, greater than 10 degrees, and in this case, the leaked stray light may be reflected back by disposing a reflection device on a side of the optical waveguide element away from the display panel to improve uniformity of light emitted from the optical waveguide element. For example, the reflecting means may be a reflective layer or other structure capable of reflecting.
For example, as shown in fig. 1A to 3, the embodiments of the present disclosure schematically show that orthographic projections of adjacent transflective elements 221 on the main surface meet each other, and dark regions where light is not emitted between the two transflective elements can be avoided. Without being limited thereto, orthographic projections of adjacent transflective elements on the main surface may partially overlap, weakening of light at edges of the transflective elements may be avoided, and light extraction may be made more uniform by the overlap of the transflective elements.
For example, as shown in fig. 1A to 3, in the direction in which the light is propagated by total reflection in the waveguide medium 210, the plurality of transflective elements 221 are uniformly arranged and the reflectance gradually increases. For example, the reflectance of the transflective element 221 decreases as the distance from the light source unit 100 decreases. For example, the reflectivities of the transflective elements sequentially arranged along the extending direction of the light-emitting surface in the transflective element array gradually increase or gradually increase regionally in the propagation direction of the light. For example, the arrangement density of the transflective elements sequentially arranged along the extending direction of the light-emitting surface in the transflective element array gradually increases or gradually increases regionally. For example, the regional increase may be two or more regions where the reflectivity of the transflective element is different and gradually increases.
The uniform arrangement may refer to an arrangement in which adjacent transflective elements are disposed such that orthographic projections thereof meet each other, or an arrangement in which adjacent transflective elements are disposed such that orthographic projections thereof partially overlap. Since the light will gradually reflect out of the waveguide medium during the propagation process and the light intensity will gradually attenuate, the light intensity reflected by each transflective element can be relatively uniform and the light output of each portion of the waveguide medium 210 can be relatively uniform by setting the transflective properties of each transflective element to be different, for example, the reflectivity of the transflective element is gradually increased along the path of the total reflection propagation of the light.
For example, the arrangement density of the plurality of transflective elements gradually increases in the direction in which the light propagates by total reflection in the waveguide medium. For example, the closer the partial transflective elements are to the light source portion, the lower the arrangement density. For example, the position where the arrangement density is small may be a position where adjacent transflective elements are disposed so that orthographic projections thereof meet each other, and the position where the arrangement density is large may be a position where adjacent transflective elements are disposed so that orthographic projections thereof partially overlap. For example, the above-mentioned position where the arrangement density is small may be such that adjacent transflective elements are arranged such that orthographic projections overlap each other with the overlapped portion being small, and the above-mentioned position where the arrangement density is large may be such that adjacent transflective elements are arranged such that orthographic projections overlap each other with the overlapped portion being large. The disclosed embodiment can also make the intensity of the light reflected by each transflective element uniform by setting the transflective property of each transflective element to be the same or almost the same and adjusting the arrangement density of the transflective elements.
For example, fig. 5 is a schematic plan view of another backlight according to the example shown in fig. 1A. The backlight of fig. 5 differs from the backlight of fig. 3 in the variation of the reflectivity of the transflective elements in the array of transflective elements. For example, as in the example shown in fig. 5, the transflective element array 220 includes at least two regions, e.g., region 01 and region 02, with the average reflectivity of the transflective elements 221 in one of the at least two regions 01 being greater than the average reflectivity of the transflective elements 221 in the other regions (e.g., region 02). The average reflectivity of the transflective element of the area 01 is greater than the average reflectivity of the transflective elements of other areas, so that the light intensity in the area 01 is greater than the light intensity in other areas.
For example, the region 01 may include at least one transflective element 221, the other region 02 includes a plurality of transflective elements 221, and the average reflectivity of the plurality of transflective elements 221 in the other region is small so that the brightness of the light emitted from the optical waveguide element is not uniform, and the optical waveguide element is suitable for an application scene of non-uniform display, such as a billboard, a display that displays content in a certain region in a concentrated manner. For example, the area 01 may be located in the middle area, and the other area 02 may surround the area 01. The embodiments of the present disclosure are not limited thereto, for example, the reflectivity of the plurality of transflective elements 221 included in the region 01 is gradually increased, and the reflectivities of the plurality of transflective elements 221 in other regions are all the same to make the brightness of the light emitted from the optical waveguide element uneven.
For example, the transflective element 221 may have no wavelength selectivity and polarization selectivity, such as an inorganic dielectric film, which is a stacked film of one or more metal oxide/metal nitride films, each having a thickness of about 10nm to 1000nm, and the overall transmission and reflection performance of the inorganic dielectric film can be controlled by changing the material and/or stacking manner of the films. Thus, the wavelength property and the polarization property of the light incident to the transflective element 221 after being transmitted and reflected by the transflective element 221 are almost unchanged.
For example, at least one transflective element 221 of the array of transflective elements 220 includes a transflective film, and light entering the optical waveguide element 200 includes light of a first polarization and light of a second polarization, the transflective film being configured to have a reflectivity for light of the first polarization that is greater than a reflectivity for light of the second polarization and a transmissivity for light of the second polarization that is greater than a transmissivity for light of the first polarization, whereby the transflective element may gradually reflect light of the first polarization out of the optical waveguide element.
The light entering the optical waveguide element may be unpolarized light or may be polarized light in two polarization states. The term "unpolarized light" used herein means that the light emitted from the light source unit may have a plurality of polarization characteristics at the same time but does not show unique polarization characteristics, for example, the light emitted from the light source unit may be considered to be composed of two orthogonal polarization states, that is, the unpolarized light emitted from the light source unit may be decomposed into two orthogonal polarization states.
For example, the transflective film may be a Brightness Enhancement Film (BEF) having a high reflectivity for light of one polarization and a high transmittance for light of another polarization (e.g., a transflective film having a high reflectivity for S-polarized light and a high transmittance for P-polarized light), and the transflective element may utilize the selectivity of polarization transreflection such that light is gradually reflected by the transflective element out of the optical waveguide element.
For example, as shown in fig. 1A, when the light emitted from the transflective element array 220 exits 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 of light rays exiting an array of transflective elements being non-perpendicular to a major surface of a waveguide medium. As shown in fig. 6, the light rays exiting the array of transflective elements may also be non-perpendicular to the major surface of the waveguide medium as the angle of the light rays incident on the transflective elements is changed, and/or the angle between the transflective elements and the major surface is changed.
In the disclosed embodiment, the light rays exiting from the array of transflective elements may or may not be perpendicular to the major surface of the waveguide medium, and the exit directions of the light rays exiting from different transflective elements may be parallel or nearly parallel, which may form a collimated beam. In the embodiment of the disclosure, the light output by the light source is converted into the collimated light of the surface light source by adopting the light waveguide element with smaller thickness, 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 sections and the arrangement of the transflective elements, and the positional relationship of adjacent transflective elements may be the same as the example shown in fig. 1A. As shown in fig. 7, the transflective element array 220 includes a first transflective element group 2201 and a second transflective element group 2202 arranged in a first direction, each transflective element group including a plurality of transflective elements 221 arranged in the first direction, the transflective elements 221 of different transflective element groups being non-parallel. For example, fig. 7 schematically illustrates that each transflective element group includes a plurality of transflective elements that are parallel to each other, and that the transflective elements in the different transflective element groups are not parallel.
For example, as shown in fig. 7, 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 transflective element array 220 in the first direction, a first transflective element group 2201 is configured to reflect light entering the optical waveguide element 200 from the first light source section 110, and a second transflective element group 2202 is configured to reflect light entering the optical waveguide element 200 from the second light source section 120. For example, the first transflective element group 2201 is configured to reflect only light rays entering from the first light source section 110, and the second transflective element group 2202 is configured to reflect only light rays entering from the second light source section 2202. The embodiment of the disclosure can improve the intensity of the emergent light of the optical waveguide element by arranging the two light source parts and the two sets of transflective element sets.
For example, as shown in fig. 7, one of the transflective elements 221 in the first transflective element group 2201 and the transflective element 221 in the second transflective element group 2202 has an acute angle with respect to the first direction (the direction indicated by the arrow of X), and the other has an obtuse angle with respect to the first direction, the first transflective element group may reflect only light entering from the first light source section, and the second transflective element group may reflect only light entering from the second light source section. For example, the transflective elements 221 in the first transflective element group 2201 and the transflective elements 221 in the second transflective element group 2202 have different tilt directions.
For example, the light source unit may be located between the first transflective element group and the second transflective element group in the extending direction of the light emitting surface.
For example, the backlight source may further include a reflection device disposed on the other side away from the light exit surface side of the optical waveguide element, for reflecting the light leaked from the optical waveguide element back to the optical waveguide element, so that as much light as possible is converted into collimated light and output, thereby improving 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 transflective element. As shown in fig. 8, the light source unit 100 includes a first light source unit 110 and a second light source unit 120, and the first light source unit 110 and the second light source unit 120 are respectively located at both sides of the transflective element array 220 in the first direction. Both side surfaces of each transflective element 221 can reflect the light entering from the first light source 110 or the second light source 120, so that both side main surfaces of the optical waveguide element are light emitting surfaces.
For example, the reflectivity of the transflective elements at and/or near the middle is greater than the reflectivity of the transflective elements at the two side positions, so that the light exiting the light guide element has 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 guide element 200, and the light splitting element 300 is configured to split the light emitted from the light source section 100 to the light guide element 200 into a plurality of sub-beams. For example, the light splitting element 300 may split the light emitted from the light source 100 to the optical waveguide 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 optical waveguide element 200 includes a plurality of sub optical waveguide elements 201, and a plurality of sub optical beams are configured to enter the plurality of sub optical waveguide elements 201 and to be reflected out of the optical waveguide element 200 by the transflective element array 221 located in each sub optical waveguide element 201. For example, the transflective element array includes a plurality of sub transflective element arrays respectively located in the plurality of sub optical waveguide elements. For example, the plurality of sub transflective element arrays correspond one-to-one to the plurality of sub optical waveguide elements.
For example, the number of the plurality of sub optical waveguide elements 201 may be the same as the number of the plurality of sub beams, and at this time, the plurality of sub beams are configured to enter the corresponding sub optical waveguide elements one by one. The embodiments of the present disclosure are not limited thereto, and the number of the plurality of sub optical waveguide elements may also be smaller than the number of the plurality of sub light beams, in which case, at least two sub light beams enter the same sub optical waveguide element.
For example, the thickness of the plurality of sub optical waveguide elements 201 is smaller than the thickness of the optical waveguide element in the embodiment shown in fig. 1A; the light transmitted in one optical waveguide element originally is split into a plurality of thinner waveguide elements, and is transmitted in the waveguide element 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 optical waveguide 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; therefore, before the light emitted by the light source enters the light guide element or is coupled out from the light guide 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 brightness uniformity, and thus a thinner optical waveguide 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-optical waveguide elements are arranged to couple out the plurality of sub-beams entering the sub-optical waveguide elements, so that the uniformity of the light emitted from the backlight source can be further improved.
For example, the plurality of sub optical waveguide elements may be independent structures or may be integrated on the same substrate.
For example, each sub optical waveguide element includes a waveguide medium, and the refractive indexes of the waveguide mediums in different sub optical waveguide elements may be the same or different, which is not limited in the embodiments of the present disclosure.
For example, the number and arrangement of the transflective elements included in the transflective element array in each sub optical waveguide element may be the same or different, and the embodiment of the present disclosure does not limit this.
For example, each sub optical waveguide element may or may not include a light incoupling portion. For example, when each sub optical waveguide element includes a light incoupling portion, the light incoupling portions of different sub optical waveguide elements may be the same, for example, all enter in a geometric manner (for example, a non-grating incoupling manner such as prism incoupling or reflective structure incoupling), or may be different, which is not limited in the embodiments of the present disclosure.
For example, as shown in fig. 9, the optical waveguide element 200 includes a plurality of sub optical waveguide elements 201, and the transflective element array 210 includes a plurality of sub transflective element arrays respectively located in the plurality of sub optical waveguide elements 201; the backlight further includes a light splitting element 300, wherein the light splitting element 300 is configured to split the light emitted from the light source unit 100 and directed to the light guide element 200 into a plurality of sub-light beams, the sub-light beams enter the sub-light guide elements 201, and the sub-light beams entering the sub-light guide elements 201 are reflected out of the light emitting surface of the light guide element 200 by the sub-transflective element array located in the sub-light guide elements 201.
For example, the light beam emitted from the light source unit 100 and directed to the optical waveguide element 200 includes first characteristic light and second characteristic light having different characteristics, and the spectroscopic element 300 is configured to perform spectroscopic processing on the light beam emitted from the light source unit 100 and directed to the optical waveguide element 200, to cause the first characteristic light obtained by the spectroscopic processing to be incident on the first sub optical waveguide element 2011, and to cause the second characteristic light obtained by the spectroscopic processing to be incident on the second sub optical waveguide element 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 colors, respectively.
For example, the light splitting element includes a polarization light splitting element configured to reflect one of the first polarized light and the second polarized light and transmit the other of the first polarized light and the second polarized light. 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 processing on the light emitted from the light source unit 100 and emitted to the light guide 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 guide element 2012, and the first polarized beam 1001 is incident on the first sub light guide 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 transflective element of the first sub optical waveguide element 2011 is configured to have a reflectivity for the first polarized light greater than a reflectivity for the second polarized light, and the transflective element of the second sub optical waveguide 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 the backlight outgoing light can be increased, and the utilization rate of the light can be increased.
Of course, the disclosed embodiments are not limited thereto, and the transflective elements in each sub optical waveguide element may also have no polarization-selective characteristics.
For example, as shown in fig. 9, the light splitting element 300 further includes a reflection element 320, and the reflection element 320 is configured to reflect the first polarized light beam 1001 into the first sub optical waveguide element 2011. The embodiments of the present disclosure are not limited thereto, and the reflection element may also be configured to reflect the second polarized light beam into the second sub optical waveguide element. For example, the reflecting element is used to transmit the split first polarized light beam to the first sub optical waveguide element, and the reflecting element may be replaced by another element having a similar function.
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 characteristic and reflecting light of another characteristic, for example, the polarization splitting element 310 may have the characteristic of transmitting light of one polarization state and reflecting light of another polarization state, and the polarization splitting element 310 may implement beam splitting using the transflective characteristic 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 can be an optical film with polarization transflective function, in particular an optical film which can split unpolarized light into two mutually perpendicular polarized lights by transmission and reflection; 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 about 10-1000 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 transmitted P-polarized light enters the second sub optical waveguide element 2012 through the second light incoupling part 232 in the second sub optical waveguide element 2012, and the reflected S-polarized light is reflected by the reflecting element 320 and then enters the first light incoupling part 231 in the first sub optical waveguide element 2011 to enter the first sub optical waveguide element 2011. The S polarized light and the P polarized light pass through the transflective element arrays in the respective waveguide elements and are output in a state of collimated light, so that 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 sub light waveguide elements are overlapped in a direction perpendicular to the display surface of the display panel, so that the brightness of the backlight can be improved, and the uniformity of light can be improved. The overlapping arrangement includes a completely overlapping arrangement and a partially overlapping arrangement, that is, orthographic projections of the plurality of sub optical waveguide elements on a plane parallel to the light exit surface of the optical waveguide element may be completely overlapped or partially overlapped, which is not limited by the embodiment of the present disclosure. Fig. 9 schematically shows a first sub optical waveguide element arranged completely overlapping a second sub optical waveguide element.
For example, as shown in fig. 9, the first sub light waveguide element 2011 and the second sub light waveguide element 2012 overlap in a direction perpendicular to the display surface of the display panel, that is, the first sub light waveguide element 2011 and the second sub light waveguide element 2012 overlap in the Y direction, and the light emitted from the second sub light waveguide element 2012 passes through the first sub light waveguide element 2011 and is emitted to the display panel. For example, as shown in fig. 9, the light emitted from the second sub optical waveguide element 2012 may or may not pass through the transflective element array in the first sub optical waveguide element 2011, which is not limited in the embodiment of the present disclosure.
For example, when light exiting the second sub optical waveguide element passes through the transflective element array in the first sub optical waveguide element, the transflective element array in the first sub optical waveguide 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 transflective element of the first sub optical waveguide element 2011 and the transflective element is a third angle, an angle between the second polarized light beam 1002 transmitted to the transflective element of the second sub optical waveguide element 2012 and the transflective 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 the transmitted light incident on the surface of the transflective element and the transflective element.
For example, if the third angle and the fourth angle are equal, the angle of the polarized light entering the sub optical waveguide elements can be adjusted according to the inclination angle of the transflective element in each sub optical waveguide element. For example, setting the included angles between different sub optical waveguide elements and the corresponding polarized light to be the same can also facilitate the manufacture of the sub optical waveguide 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 optical waveguide element 2011 is the same as the total reflection propagation direction of the second polarized light beam 1002 entering the second sub optical waveguide element 2012, the included angle between the transflective element in the first sub optical waveguide element 2011 and the transflective element in the second sub optical waveguide element 2012 is not more than 5 degrees, for example, the transflective elements in the two sub optical waveguide elements are parallel, so as to facilitate the manufacturing of the optical waveguide elements.
For example, as shown in fig. 9, the included angles between the transflective elements in the first sub optical waveguide element 2011 and the transflective elements in the second sub optical waveguide element 2012 and the first direction are both acute angles or both obtuse angles. For example, the transflective elements in the first sub optical waveguide element 2011 and the transflective elements in the second sub optical waveguide element 2012 have the same tilt direction. The oblique direction here may refer to the oblique direction of the transflective element with respect to the light exit surface. However, the tilt direction herein may also refer to a tilt 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 angle with the direction is referred to, 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 optical waveguide element 2011 is the same as the total reflection propagation direction of the second polarized light beam 1002 entering the second sub optical waveguide element 2012, the angle between each transflective element and the first direction is an acute angle when the total reflection propagation direction of each polarized light beam is the same as the first direction; when the total reflection propagation direction of each polarized light is opposite to the first direction, the included angle between each transflective element and the first direction is 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 optical waveguide elements. As shown in fig. 10, the plurality of sub optical waveguide elements are arranged in the first direction. For example, the plurality of sub light waveguide elements do not overlap in a direction perpendicular to the display surface of the display panel, so that the thickness of the backlight can be reduced, and the degree of weakening of light intensity at the edge of the light waveguide element can be reduced by setting the length of each sub light waveguide element to be small. For example, the sub light waveguide elements 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 optical waveguide elements may include a first sub optical waveguide element 2011 and a second sub optical waveguide element 2012 arranged along a first direction, the second polarized light beam 1002 transmitted by the polarization splitting element 310 enters the second sub optical waveguide element 2012 through the second light incoupling part 232 in the second sub optical waveguide element 2012, and the reflected first polarized light beam 1001 enters the first sub optical waveguide element 2011 through the first light incoupling part 231 in the first sub optical waveguide element 2011 without passing through the reflection element. The first polarized light beam 1001 and the second polarized light beam 1002 pass through the transflective element array in each sub-waveguide element, and are output in a state of collimating light, so that 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 optical waveguide element 2011 is opposite to the total reflection propagation direction of the light in the second sub optical waveguide element 2012, and the transflective element in the first sub optical waveguide element 2011 is not parallel to the transflective element in the second sub optical waveguide element 2012, for example, an included angle between one of the two elements and the first direction is an acute angle, and an included angle between the other element and the first direction is an obtuse angle, so that the transflective element couples out the light. For example, the transflective elements in the first sub optical waveguide element 2011 have a different tilt direction than the transflective elements in the second sub optical waveguide 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 element 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 light beams includes first color light 1003 and second color light 1004 with different wavelengths, the plurality of sub light waveguide elements 201 includes a first sub light waveguide element 2011 and a second sub light waveguide element 2012, the first color light 1003 is configured to enter the first sub light waveguide element 2011 and be reflected out of the first sub light waveguide element 2011 by the transflective element array located in the first sub light waveguide element 2011, and the second color light 1004 is configured to enter the second sub light waveguide element 2012 and be reflected out of the second sub light waveguide element 2012 by the transflective element array located in the second sub light waveguide 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 optical waveguide elements, so that the utilization rate of the light rays is improved.
For example, the transflective elements of the first sub optical waveguide element 2011 are configured to have a greater reflectivity for the first color light 1003 than for the second color light 1004, and the transflective elements of the second sub optical waveguide element 2012 are configured to have a greater reflectivity for the second color light 1004 than for the first color light 1003. The embodiment of the disclosure can improve the utilization rate of light rays incident into the corresponding sub optical waveguide elements by regulating and controlling the reflectivity and the transmissivity of the transflective elements in different sub optical waveguide 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, and the third color light 1005 is configured to enter one of the first sub optical waveguide element 2011 and the second sub optical waveguide 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 waveguide element 2011, and the second color light 1004 enters the second sub light waveguide element 2012. The embodiments of the present disclosure are not limited thereto, and the third color light may also enter the same sub light waveguide element as the second color light.
In the embodiment of the disclosure, two lights with different colors enter the same sub-optical waveguide element, so that the manufacturing cost of the optical waveguide 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-optical waveguide element, so that the adjustment of the transflective element array in the sub-optical waveguide 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 to enter a plurality of sub optical waveguide elements one by one. As shown in fig. 13, the plurality of sub-beams further includes third color light 1005, the plurality of sub-optical waveguide elements 201 further includes a third sub-optical waveguide element 2013, the third color light 1005 is configured to enter the third sub-optical waveguide element 2013 and be reflected out of the third sub-optical waveguide element 2013 by the transflective element array located in the third sub-optical waveguide element 2013. The embodiment of the disclosure can further improve the utilization rate of the light by enabling the light with different colors to enter the different sub-optical waveguide elements one by one.
For example, as shown in fig. 13, the transflective elements of the first sub optical waveguide element 2011 are configured to have a greater reflectivity for the first color light 1003 than for the second and third color light 1004, 1005, the transflective elements of the second sub optical waveguide element 2012 are configured to have a greater reflectivity for the second color light 1004 than for the first and third color light 1003, 1005, and the transflective elements of the third sub optical waveguide element 2013 are configured to have a greater reflectivity for the third color light 1005 than for the first and second color light 1003, 1004. The embodiment of the disclosure can improve the utilization rate of light rays incident into the corresponding sub optical waveguide elements by regulating and controlling the reflectivity and the transmissivity of the transflective elements in different sub optical waveguide elements.
For example, as shown in fig. 13, the refractive index of the waveguide medium of the first sub optical waveguide element 2011, the refractive index of the waveguide medium of the second sub optical waveguide element 2012, and the refractive index of the waveguide medium of the third sub optical waveguide element 2013 may be different and each set to accommodate the refractive index of light entering the corresponding sub optical waveguide element. For example, the first color light 1003, the second color light 1004, and the third color light 1005 are blue light, red light, and green light, respectively, if three kinds of light are coupled into the same optical waveguide device, the light with different wavelengths propagates in the same medium, and the refractive indexes of the medium to the various light are different, so the total reflection angles of the light with the three wavelengths are different (for example, the critical angle of total reflection of red light is greater than that of blue light), and the angle set by the transflective device 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. Therefore, various light rays are separated, and each sub optical waveguide element can select a medium and a corresponding transflective element which can transmit the corresponding light rays as far as possible under the total reflection condition, so that the light ray 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, that is, the light splitting element is only configured to split one beam of light 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-optical waveguide elements one by one. For a bundle of light that jets out with light source portion gets into an optical waveguide component, this disclosed embodiment divides into a plurality of light through a bundle of light that jets out with light source portion, and gets into respectively in the different sub-optical waveguide component, can improve the utilization ratio of light, also can promote the homogeneity of the light of outing. When the sub-light beams in the sub-light beams have the same property, the sub-light waveguide elements may or may not overlap in a direction perpendicular to the display surface of the display panel.
For example, the optical waveguide element includes a plurality of sub optical waveguide elements, and whether the plurality of sub optical waveguide elements are arranged in a direction parallel to the display surface of the display panel or in a direction perpendicular to the display surface of the display panel, in at least one of the plurality of sub optical waveguide elements, the plurality of transflective elements are uniformly arranged and the reflectance gradually increases along the direction in which the light is propagated by total reflection in the waveguide medium.
For example, the optical waveguide element includes a plurality of sub optical waveguide elements, and the plurality of sub optical waveguide elements are arranged in either a direction parallel to the display surface of the display panel or a direction perpendicular to the display surface of the display panel, and in at least one of the plurality of sub optical waveguide elements, the arrangement density of the plurality of transflective elements gradually increases along the direction in which the 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 optical waveguide element 200 includes a light outcoupling portion 240. The light source unit 100 is configured such that light emitted therefrom enters the optical waveguide device 200 and then propagates in the optical waveguide device 200 in a reflective manner, and the light outcoupling unit 240 is configured such that light propagating in the optical waveguide device 200 in a reflective manner is outcoupled. The light outcoupling part 240 includes a first light outcoupling part 241 and a second light outcoupling part 242, the first light outcoupling part 241 being configured to outcouple the first polarized light 100-1 entering the optical waveguide element 200; the light source device further includes a polarization conversion structure 400, and the polarization conversion structure 400 is configured to convert the second polarized light 100-2 after entering the optical waveguide 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 optical waveguide 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 optical waveguide 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 guide element 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 optical waveguide element 200 includes a waveguide medium 210 and a light outcoupling portion 240, the light emitted from the light source portion 100 is configured to enter the waveguide medium 210 and propagate by total reflection in the waveguide medium 210, and the light outcoupling portion 240 is configured to outcouple the light propagating by total reflection in the waveguide medium 210 to the 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 outcoupling portion 241 is configured to outcouple the first polarized light beam 1001 entering the optical waveguide member 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 waveguide element 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 on 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 is not described herein again.
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 embodiments of the present disclosure are not limited to the light emitted from the light source unit including only two polarization states, and 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 in the light emitted from the light source unit 100, that is, the 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, the embodiments of the present disclosure are not limited to that the light entering the optical waveguide device from the light source unit propagates through the optical waveguide device by total reflection, and for example, the light emitted from the light source unit may also propagate through the transflective device by non-total reflection, for example, may propagate along a straight line.
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 unit 100 and directed to the light guide element 200. For example, the light splitting element 300 may be located between the light source unit 100 and the light waveguide element 200, and configured to split the light emitted from the light source unit 100 to the light waveguide 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 that the light source unit 100 emits to the optical waveguide element 200 into the first polarized light beam 1001 and the second polarized light beam 1002 before the light enters the optical waveguide element 200.
For example, as shown in fig. 15, the optical waveguide element 200 includes a first sub-element 2001 and a second sub-element 2002, and the first sub-element 2001 is provided with a first light out-coupling 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, that is, 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, if the first sub-element and the second sub-element shown in fig. 15 are both provided with the light outcoupling portion, the configuration may be the same as that of the sub optical waveguide element described in fig. 9 or may be different.
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 (i.e., 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, e.g. a complete overlap or a partial overlap of the orthographic projections of the first and second subelements on a plane parallel to the light exit face. 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 overlap in the Y direction, the converted first polarized light beam 1001' passes through the first sub-element 2001 and is directed to the predetermined region 40. For example, the converted first polarized light beam 1001' may or may not pass 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 reflection element 320, the reflection element 320 is located on a side of the polarization light splitting element 310 away from the optical waveguide element 200, and is configured to reflect the first polarized light beam 1001 into the first sub-element 2001. The reflective element in this embodiment may have the same features as the reflective element shown in fig. 9, and will not be 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 passes through 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 to the first sub-element 2001 via the reflective element 320. The S polarized light and the P polarized light are output through the light out-coupling portions in the respective sub optical waveguide elements, for example, the S polarized light is directly output through the first light out-coupling portion 241, the P polarized light is output through the second light out-coupling portion 242, then is converted into the S polarized light through the polarization conversion element 400, and then is output through the first sub element 2001, so that the non-polarized light emitted by the light source portion is converted into the same polarized light.
For example, the polarization conversion element may be an 1/2 wave plate. The embodiments of the present disclosure are not limited thereto, and it may be sufficient that the second polarized light is converted 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 portion 240 includes a transflective element array 220, each transflective element of the transflective element array 220 is configured to reflect a part of the light propagating to the transflective element to a predetermined region, and transmit another part to the waveguide medium 210 to continue total reflection propagation. The waveguide medium 210 includes a main surface, the transflective element array 220 includes a plurality of transflective elements 221 arranged along a first direction, the first direction is parallel to the main surface, an included angle between each transflective element 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 difference between the first included angle and the second included angle is not greater than 5 degrees. For example, the first angle and the second angle are equal, that is, the light totally reflected in the waveguide medium 210 is parallel to the transflective elements 221, so that the light is reflected once in each transflective element, for example, the light parallel to the transflective elements 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 disclosure is not limited thereto, and the angle between the transflective element and the light propagated by total reflection may also be greater than 5 degrees, and at this time, the reflective structure is disposed on the side of the optical waveguide element away from the display panel, so that the leaked stray light can be reflected back to improve the uniformity of the light emitted from the optical waveguide element.
For example, as shown in fig. 16, the transflective element array 220 in the first light out-coupling portion 241 includes a plurality of first transflective elements 2211 arranged in the first direction, and the transflective element array 220 in the second light out-coupling portion 242 includes a plurality of second transflective elements 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 transflective element 2211 and the first transflective element 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 transflective element 2212 and the second transflective element 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-elements can be adjusted according to the inclination angle of the transflective element 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 transflective element 2211 and the second transflective element 2212 may be not more than 5 degrees, for example, the first transflective element 2211 may be parallel to the second transflective element 2212, so as to facilitate the fabrication of the optical waveguide element.
For example, as shown in fig. 16, the angles between the first transflective element 2211 and/or the second transflective element 2212 and the first direction are both acute angles or both 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 transflective element and the first direction is an acute angle; when the total reflection propagation direction of each polarized light is opposite to the first direction, the included angle between each transflective element and the first direction is an obtuse angle. The angle between the transflective element and the first direction is related to the total reflection propagation direction of the polarized light.
For example, as shown in fig. 16, the first transflective element 2211 is configured such that the reflectivity for the first polarized light beam 1001 is greater than the reflectivity for the second polarized light beam 1002, and the transmissivity for the second polarized light beam 1002 is greater than the transmissivity for the first polarized light beam 1001.
The arrangement of the transflective elements in the embodiments of the present disclosure may have the same features as the arrangement of the transflective elements 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 or may not pass through the transflective element array 220 in the first sub-element 2001, and the embodiment of the disclosure does not limit this. For example, when polarized light exiting the second sub-element passes through the transflective element array in the first sub-optical waveguide element, the transflective element array in the first sub-element has a higher transmittance for the polarized light exiting the second sub-element.
For example, the light outcoupling portion is not limited to the transflective element array, and 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 optical waveguide 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 the positional relationship between the first subelement and the second subelement shown in fig. 17. 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 perpendicular to the light-emitting surface (i.e., Y direction), so that the thickness of the backlight 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 optical waveguide 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, and at this time, the transflective element in the first sub-element 2001 is not parallel to the transflective element 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 couple out light rays by the transflective element.
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 are both located in the first sub-element 2001. In this example, the light incident on the optical waveguide element 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, and 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 optical waveguide element 200 or may be provided outside the optical waveguide 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 the present example may have the same features as those of the light splitting element in the example shown in fig. 15, and will not be described herein again. For example, the waveguide medium in the optical waveguide element of the present example may have the same characteristics 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. 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 perpendicular to the light exit surface (i.e., Y direction). The polarization conversion structure 400 is located at the light incident side of the second light out-coupling portion 242, and the second polarized light beam 1002 entering the second sub-element 2002 is configured to propagate through the second sub-element 2002 by total reflection, and is coupled out by the second light out-coupling portion 242 after passing through 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 the utility model 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 outcoupling unit, that is, the second polarized light propagating in the second sub-element is converted into the first polarized light by the polarization conversion structure, and the first polarized light is outcoupled by the second light outcoupling unit.
For example, the second sub-element 2002 may include other light out-coupling portions (for example, the second sub-element is in a separate structure from the first sub-element), or may not include a light out-coupling portion (for example, the first sub-element is in an integrated structure with the second sub-element), and the second sub-element is mainly configured to allow the second polarized light to 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 light of the second polarization may be converted into light of the first polarization after passing through the polarization conversion structure only once, and the polarization conversion structure may be, for example, an 1/2 wave plate. 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 an 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 passes through the polarization splitting element 310 having the polarization splitting function, transmits the P-polarized light beam, and reflects the S-polarized light beam (or vice versa). The transmitted P-polarized light enters the second sub-element 2002 through the second light incoupling portion 232, and is propagated to the reflective structure 500 at the end surface by total reflection in the waveguide medium of the second sub-element 2002, and the reflected light no longer satisfies the total reflection condition, and the reflected light will leave 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 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, that is, the P-polarized light is converted into S-polarized light after passing through the polarization conversion structure 400 twice, and the converted S-polarized light enters the waveguide medium of the first sub-element 2001 through the third light entrance part 233, is totally reflected, is transmitted to the second light coupler exit part 242, and is coupled out from the first sub-element 2001.
For example, as shown in fig. 19, each of the first light out-coupling portion 241 and the second light out-coupling portion 242 includes the transflective element array 220, and each transflective element 221 included in the transflective element array 220 has an approximately equal angle with respect to a light ray incident on a surface thereof. For example, the transflective element array 220 in the first light outcoupling portion 241 includes a plurality of first transflective elements 2211 arranged in the first direction, and the transflective element array 220 in the second light outcoupling portion 242 includes a plurality of second transflective 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 out-coupling portion 241 is opposite to the total reflection propagation direction of the converted first polarized light beam 1001' incident to the second light out-coupling portion 242, the first transflective element 2211 is not parallel to the second transflective element 2212, i.e. the two transflective elements have different inclination directions, for example, an included angle between one of the first transflective element 2211 and the second transflective element 2212 and the first direction is an acute angle, and an included angle between the other of the first transflective element 2211 and the second transflective element 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 optical waveguide element.
As shown in fig. 20, the optical waveguide element 200 includes a first sub-element 2001 and a second sub-element 2002, the first sub-element 2001 includes the first light out-coupling portion 241, and the second sub-element 2002 includes the second light out-coupling portion 242. For example, when both the first sub-element and the second sub-element shown in fig. 20 are provided with the light outcoupling portion, the configuration may be the same as that of the sub optical waveguide element described in fig. 9 or may be different.
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 optical waveguide element 200 includes a first sub-element 2001 and a second sub-element 2002, the first sub-element 2001 is provided with a first light 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 to the unpolarized light that light source portion got into through the light outcoupling portion that is located in the optical waveguide component, can omit the volume of setting in order to save the backlight of beam splitting device.
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 optical waveguide element of the present example may have the same characteristics 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 optical waveguide element 200, but directly enters the first sub-element 2001, in which case 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, each of the first light out-coupling portion 241 and the second light out-coupling portion 242 includes the transflective element array 220, and each transflective element 221 included in the transflective element array 220 has an approximately equal angle with respect to a light ray incident on a surface thereof. For example, the transflective element array 220 in the first light outcoupling portion 241 includes a plurality of first transflective elements 2211 arranged in the first direction, and the transflective element array 220 in the second light outcoupling portion 242 includes a plurality of second transflective 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 out-coupling portion 241 is opposite to the total reflection propagation direction of the converted first polarized light beam 1001' incident to the second light out-coupling portion 242, the first transflective element 2211 is not parallel to the second transflective element 2212, i.e. the two transflective elements have different inclination directions, for example, an included angle between one of the first transflective element 2211 and the second transflective element 2212 and the first direction is an acute angle, and an included angle between the other of the first transflective element 2211 and the second transflective element 2212 and the first direction is an obtuse angle.
The embodiments of the present disclosure are not limited thereto, when the first sub-element and the second sub-element are arranged along the X direction, 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 converted first polarized light incident to the second light out-coupling portion, and then the first transflective element and the second transflective element may be substantially parallel, that is, inclination directions of the first transflective element and the second transflective element are the same, for example, included angles between the first transflective element and the first direction and between the second transflective element and the first direction are both acute angles or obtuse angles.
For example, the first transflective element 2211 may be an element having a high reflectivity for the first polarized light beam 1001 and a high transmittance for the second polarized light beam 1002 to realize light splitting for unpolarized light. For example, the second transflective element 2212 may be a transflective element with no polarization selection characteristic, or an element with high reflectivity for the first polarized light, which is not limited by the embodiments 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 propagate in the first sub-element 2001 and the second sub-element 2002 by total reflection, but the light rays entering the first sub-element from the light source unit 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 transflective element.
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 optical waveguide 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 as to be incident on the polarization conversion structure 400.
For example, polarization conversion structure 400 may be an 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 guide plate 2000, the light guide plate 2000 includes a light uniformizing portion 250 and a light guide element 200, the light guide element 200 includes a light emitting surface, and the light uniformizing portion 250 and the light guide element 200 are sequentially arranged, for example, stacked, in a direction perpendicular to the light emitting surface. The light source unit 100 is configured such that light emitted therefrom enters the optical waveguide device 200 after being totally reflected a plurality of times in the dodging unit 250, and then exits from the light exit surface of the optical waveguide device 200.
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. For example, the number of total reflections may be 6 to 12. For example, the number of total reflections may be 6 to 8.
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 uniform light portion 250 in the direction perpendicular to the light exit surface is not greater than the thickness of the optical waveguide element 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 optical waveguide element 200 includes a waveguide medium 210 and a light outcoupling portion 240. The optical waveguide element 200 further includes a uniform light section 250, the light from the light source section 100 passes through the uniform light section 250 and then reaches the light outcoupling section 240, and the light entering the optical waveguide element 200 is configured to propagate by total reflection 8 to 11 times in the uniform light section 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 optical waveguide element 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 optical waveguide 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. The embodiment of the disclosure 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, just output after the light homogenization to obtain the even area light source light of light and shade promptly.
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 different refractive indexes, which is not limited in the embodiments of the present disclosure.
For example, the dodging portion shown in fig. 22 may be further provided in any of the examples shown in fig. 1A to 21 to further improve the uniformity of the light output from 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 dodging section 250 in the X direction may be not less than the length of the transflective element array as the light outcoupling section 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 1/3-2/3 of the length of the transflective element array in the X direction as the light out-coupling part 240.
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 uniform light portion 250 may be disposed between the light incoupling portion 230 and the light outcoupling portion 240 of the optical waveguide element 200, or may be disposed between the light incoupling portion and the light source portion, 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 through a light coupling-out part (e.g., a transflective element array) 240, for example, converted into a collimated and parallel light beam to be emitted.
For example, as shown in fig. 23, the light uniformizing part 250 may perform total reflection on the light entering the light uniformizing part for multiple times, for example, 8 to 11 times, so as to make the light beam be uniformly distributed, thereby achieving the light uniformizing 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. Therefore, the dodging portion needs to be disposed in front of the light outcoupling portion.
For example, as shown in fig. 22 and 23, the light out-coupling portion 240 includes a plurality of light out-coupling portions 2401 aligned in the first direction (i.e., X direction), and the light uniformizing portion 250 and the light out-coupling portion 240 are aligned 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 optical waveguide element 200 includes a light-emitting surface 001, the light out-coupling portion 240 and the waveguide medium 210 are 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 are both greater than a refractive index of the gap medium 260. This disclosed embodiment is through setting up the even and even light portion overlap of optical coupling out portion and waveguide medium, 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 unit 250 in the X direction may be not less than the length of the transflective element array as the light out-coupling unit 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 unit 250 in the X direction may be 1/3 to 2/3 of the length of the transflective element array as the light out-coupling unit 240 in the X direction.
For example, as shown in fig. 24, a connection portion 270 is further disposed between the optical waveguide element 200 and the dodging portion 250, and the connection portion 270 connects the light input end of the optical waveguide element 200 and the light output end of the dodging portion 250, so that the light of the dodging portion 250 enters the optical waveguide 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 optical waveguide element 200.
For example, as shown in fig. 24, the connecting portion 270 further includes a reflecting surface 272, and the reflecting surface 272 is configured to reflect the light in the dodging portion 250 into the optical waveguide element 200. In the embodiment of the present disclosure, the connection portion may include at least one of the light modulation portion and the reflection surface, and fig. 24 schematically illustrates that the connection portion includes the light modulation portion and the reflection surface, but is not limited thereto, and the connection portion may include only the light modulation portion, or only the reflection 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 outcoupling part (e.g., a transflective element array) located on the display panel-facing side of the light uniformizing part 250.
For example, the light adjusting portion 271 may be used as both the light out-coupling portion of the light uniformizing portion 250 and the light in-coupling portion of the waveguide medium, or may be used as only the light out-coupling portion of the light uniformizing portion 250, or only the light in-coupling portion of the waveguide medium, which is not limited in this 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 destroys the total reflection condition of the light, so the light is continuously transmitted to the reflection surface 272 and reflected, the reflected light is transmitted to the light outcoupling portion 340 (e.g., transflective element array), and then is outcoupled by the light outcoupling portion 340, for example, is converted into collimated and parallel light to be outcoupled.
For example, as shown in fig. 22 to 24, an embodiment of the present disclosure further provides a light source device, where the light source device includes a light guide plate 2000 and a light source portion 100, the light guide plate 2000 includes a light uniformizing portion 250 and a light guide element 200, the light guide element 250 includes a light emitting surface, and the light uniformizing portion 250 and the light guide element 200 are sequentially arranged in a direction perpendicular to the light emitting surface; the light source unit 100 is configured such that light emitted therefrom enters the optical waveguide device 200 after being totally reflected a plurality of times in the dodging unit 250, and then exits from the light exit surface of the optical waveguide device 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 device, 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 emitting.
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 located between the light waveguide element 200 and the display panel 10, and the light diffusing element 30 is configured to diffuse the light emitted from the light waveguide element 200, that is, the light diffusing element 30 is configured to diffuse the light flux passing through the light diffusing element 20. 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 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 arranged 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 without changing the optical axis of the light beam. The "optical axis" refers to the center line of the light beam.
For example, after the incident light beam passes through the light diffusion element 30, the incident light beam is diffused into a light spot having a specific size and shape along the propagation direction and having a uniform energy distribution, and the size and shape of the light spot can be precisely controlled by the specific microstructure designed on the surface of the light beam diffusion structure 30. The particular shapes may include, but are not limited to, linear, circular, elliptical, square, and rectangular.
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 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 more precisely, such as a Beam Shaper (Beam Shaper). For example, the diffractive optical element has a light beam expanding effect by diffraction by designing a specific microstructure on the surface, the light spot is small, and the size and the 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 located between the light guide element 200 and the light diffusing element 30, and is configured to converge the light emitted from the light guide element 200 toward the display panel 10. The backlight in the embodiments of the present disclosure may be the backlight shown in any one of fig. 1A to 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 guide 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 region, and the light converging element is arranged to uniformly adjust the direction of the collimated light output by the light guide 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 guide element 200 to a certain range, and the light diffusing element 30 may diffuse the converged light. The disclosed embodiment provides high light efficiency and enlarges the visual range through 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, and therefore the collimated light beam output by the light guide element 200 is easy to control to realize convenient adjustment of the direction of the light rays. For example, an area where an observer needs to view imaging, that is, an eye box area (eyebox)003, may be preset according to actual needs, and the eye box area 003 refers to an area where both eyes of the observer are located and where an image displayed by the display device can be seen, and may be a planar area or a stereoscopic area, for example.
For example, as shown in fig. 26, the light emitted from the light source 100 is converted into collimated light that is emitted uniformly by the light guide 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 further the light is 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 the normal observation is not affected while the high luminous efficiency is achieved. The embodiments of the present disclosure are not limited thereto, and the diffused light beam may also be larger than the eye box area, at least to completely cover the eye box; for example, the embodiments of the present disclosure may arrange the light diffusion element so that the diffused light beam just covers the eye box region, when the light efficiency of the display device is 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 is different from the example shown in fig. 26 in the positional relationship of the light converging element and the optical waveguide element. As shown in fig. 27, the light converging element 40 is of an integral structure with the optical waveguide element 200. The embodiment of the disclosure can reduce the thickness of the display device and facilitate the implementation and installation by arranging the light converging element and the light waveguide element into an integrated structure, can also prevent unnecessary reflection of light rays generated on the interface between air and the light waveguide element and/or the light converging element, and can reduce or avoid 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 optical waveguide element 200, and the refractive index of the transparent medium layer 50 is smaller than that of the optical waveguide element 200 so as to satisfy the total reflection condition of the light rays transmitted in the waveguide medium. For example, the thickness of the transparent dielectric layer may be small enough to satisfy a total reflection propagation condition when light propagates in the waveguide medium.
For example, the transparent dielectric layer 50 may be a medium having a high transmittance, such as a transparent optical adhesive, which can bond the light converging element and the optical waveguide element and improve the transmittance of light.
For example, the light converging element 40 and the optical waveguide 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 a backlight is unpolarized light or light emitted from a light source section toward an optical waveguide element is unpolarized light, and a display panel is configured to generate image light using first polarized light or second polarized light. The backlight here may be a backlight that satisfies this condition in the above-described embodiment. The term "unpolarized light" used herein means that the light emitted from the light source unit may have a plurality of polarization characteristics at the same time but does not show unique polarization characteristics, for example, the light emitted from the light source unit may be considered to be composed of two orthogonal polarization states, that is, the unpolarized light emitted from the light source unit may 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 provided at a plurality of positions, for example, configured to collect light emitted from the light source section and send the collected light to the light guide member, and/or to collect light emitted from the light guide member and send the collected light to the display panel.
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 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 the light conversion device 50 located between the light converging element 40 and the light guide element 200, but the light conversion device may be located between the light guide element and the light source unit, 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 so as 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, a direction changing element 52, and a polarization conversion element 53. For example, the beam splitting element 51 is configured to split the light incident to the beam splitting element 51 into the first polarized light beam 101 and the second polarized light beam 102 having different polarization states, 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, both the first polarized light beam 101 and the second polarized light beam 102 are 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 splitter 51 reflects the S-polarized light and transmits the P-polarized light (first polarized light beam 101), and the direction changer 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 is converted into the S polarized light usable by the display panel.
For example, the beam splitting element 51 may have the function of transmitting light of one characteristic and reflecting light of another characteristic, e.g., the beam splitting element 51 may have the characteristic of transmitting light of one polarization and reflecting light of another polarization, which may be used to achieve beam splitting using the transflective characteristic described above.
For example, the beam splitting element 51 may be a transflective film, which performs a 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 can be an optical film with polarization transflective function, in particular an optical film which can split unpolarized light into two mutually perpendicular polarized lights by transmission and reflection; 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 about 10-1000 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 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 exiting from the beam splitting element 51 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, which are the same as those of the transflective film included in the beam splitting element 51, that is, characteristics of reflecting S-polarized light and transmitting P-polarized light. 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 an 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, 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 device shown in fig. 29 is different from the light conversion device shown in fig. 28 in the location of the polarization conversion element and the light in 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 device may be the same as those of the elements shown in fig. 28, and are not described again here.
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 third polarized light 103, the third polarized light 103 is reflected by the direction changing element 52 and is converted into the 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, into the third polarized light 103, such as circularly polarized light or elliptically polarized light. The third polarized light 103 incident to 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 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 apparatus in this example may be the same as those of the corresponding elements shown in fig. 28, and are not described again here.
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 exiting from the display panel 10 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, 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, so that 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 a windshield (e.g., windshield) or an imaging window of a motor vehicle, corresponding to a windshield head-up display (W-HUD) and a combined head-up display (C-HUD), respectively.
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 can also be 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.
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 device includes a head-up display provided by at least one embodiment of the present disclosure. The 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 of the disclosure and of different embodiments 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 (23)
1. A light source device, comprising:
a light source unit that emits light including first polarized light and second polarized light having different polarization states;
an optical waveguide element comprising a light out-coupling portion,
wherein the light source part is configured to make the light emitted by the light source part propagate in the optical waveguide element in a reflection mode after entering the optical waveguide element, and the light out-coupling part is configured to couple out the light propagating in the optical waveguide element in the reflection mode;
wherein the light out-coupling comprises a first light out-coupling configured to couple out the first polarized light entering the optical waveguide element and a second light out-coupling;
the light source device further includes a polarization conversion structure configured to convert the second polarized light after entering the optical waveguide element into first polarized light,
the second light out-coupling portion is configured to: after the polarization conversion structure converts the second polarized light entering the optical waveguide element into first polarized light, coupling the converted first polarized light out; or the second light out-coupling part is configured to: coupling out the second polarized light entering the optical waveguide element to the polarization conversion structure such that the coupled out second polarized light is converted to the first polarized light by the polarization conversion structure.
2. The light source device according to claim 1, wherein the light waveguide element further includes a waveguide medium, the light source unit is configured to make the light emitted from the light source unit enter the waveguide medium and propagate through the waveguide medium by total reflection, and the light outcoupling unit is configured to outcouple the light propagating through total reflection in the waveguide medium to a predetermined region.
3. The light source device according to claim 1, further comprising:
a light splitting element configured to perform light splitting processing on the light emitted from the light source unit and directed to the optical waveguide element;
wherein the optical waveguide element comprises a plurality of sub-elements including a first sub-element and a second sub-element,
the first sub-element comprises the first light out-coupling part, and the first polarized light subjected to the light splitting treatment is coupled out by the first light out-coupling part after entering the first sub-element;
the second polarized light after the light splitting process enters the second subelement.
4. The light source device according to claim 3, wherein the light splitting element includes a polarization light splitting element configured to reflect one of the first polarized light and the second polarized light and transmit the other of the first polarized light and the second polarized light;
the light splitting element further includes a reflective element configured to reflect one of the first polarized light and the second polarized light.
5. A light source device according to claim 3, wherein the second sub-element comprises the second light out-coupling portion, and the polarization conversion structure is configured to convert the second polarized light out-coupled from the second light out-coupling portion into the first polarized light; and the number of the first and second electrodes,
wherein the first sub-element comprises a light exit surface, the first sub-element and the second sub-element overlap in a direction perpendicular to the light exit surface, and the polarization conversion structure is located between the first sub-element and the second sub-element; or
The first sub-element comprises a light exit surface, and the first sub-element and the second sub-element are not overlapped in a direction perpendicular to the light exit surface.
6. A light source device according to claim 3, wherein the first sub-element comprises the second light out-coupling portion, the first sub-element comprises a light exit face, the first sub-element and the second sub-element overlap in a direction perpendicular to the light exit face,
the polarization conversion structure is located on the light incident side of the second light out-coupling portion, and after the second polarized light entering the second sub-element is transmitted in the second sub-element in a total reflection manner and is converted into first polarized light by the polarization conversion structure, the first polarized light obtained through conversion is out-coupled by the second light out-coupling portion.
7. The light source device according to claim 6, wherein the second sub-element is provided with a reflection structure, the second polarized light that is totally reflected to propagate in the second sub-element enters the first sub-element after being converted by the polarization conversion structure and reflected by the reflection structure,
the polarization conversion structure is provided in the optical waveguide element or outside the optical waveguide element.
8. A light source device according to claim 1, wherein the light waveguide element comprises a first sub-element and a second sub-element, the first sub-element comprising the first light out-coupling portion, the second sub-element comprising the second light out-coupling portion;
the light source part is configured to make the light emitted by the light source part enter the first sub-element, the first polarized light in the light is coupled out by the first light out-coupling part, and the second polarized light in the light propagates to the polarization conversion structure in the first sub-element to be converted into first polarized light;
the first polarized light obtained after conversion by the polarization conversion structure is transmitted to the second light out-coupling portion in the second sub-element to be out-coupled by the second light out-coupling portion.
9. The light source device according to claim 8, wherein the light source unit is configured such that the light emitted from the light source unit propagates by total reflection in at least one of the first subelement and the second subelement.
10. The light source device according to claim 8, wherein the first sub-element comprises a light exit surface, and the first sub-element and the second sub-element overlap in a direction perpendicular to the light exit surface.
11. The light source device of claim 8, wherein the polarization conversion structure is disposed between the first subelement and the second subelement; or
The first sub-element is provided with the polarization conversion structure, and the polarization conversion structure is positioned on one side of the first light out-coupling part, which is far away from the light incident side of the first sub-element; alternatively, the first and second electrodes may be,
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.
12. A light source device according to any one of claims 1 to 11, wherein the light out-coupling portion comprises an array of transflective elements, each transflective element of the array of transflective elements being configured to reflect a portion of the light rays propagating to the transflective element out of the light guide element and to transmit another portion of the light rays;
the optical waveguide element comprises a light-emitting surface, an included angle between each transflective element and the light-emitting surface is a first included angle, and the sum of the first included angle and a total reflection critical angle of the light rays totally reflected on the light-emitting surface is within the range of 60-120 degrees.
13. A light source device according to claim 12, wherein the array of transflective elements in the first light out-coupling portion comprises a plurality of first transflective elements arranged along an extension direction of the light exit face, and the array of transflective elements in the second light out-coupling portion comprises a plurality of second transflective elements arranged along the extension direction,
the included angle between the first polarized light transmitted to the first transflective element and the first transflective element is a third included angle, the included angle between the second polarized light transmitted to the second transflective element and the second transflective element is a fourth included angle, and the difference between the third included angle and the fourth included angle is not greater than 10 degrees.
14. A light source device according to claim 13, wherein the direction of tilt of the first transflective element and the direction of tilt of the second transflective element are the same or different.
15. The light source device according to claim 13, wherein the first transflective element is a transflective element having a reflectance for the light of the first polarization greater than a reflectance for the light of the second polarization and a transmittance for the light of the second polarization greater than a transmittance for the light of the first polarization.
16. The light source device of claim 15, wherein the array of transflective elements comprises at least some of the plurality of transflective elements arranged in sequence along a first direction and extending along a second direction that intersects the first direction,
the light source section includes a plurality of sub light sources arranged in the second direction, the plurality of sub light sources being configured to emit light rays entering the at least partially transflective element.
17. The light source device according to claim 2, further comprising:
a light splitting element configured to perform light splitting processing on the light emitted from the light source unit and directed to the optical waveguide element;
wherein the optical waveguide element comprises a plurality of sub-elements including a first sub-element and a second sub-element,
the first sub-element comprises the first light out-coupling part, and the first polarized light subjected to the light splitting treatment is coupled out by the first light out-coupling part after entering the first sub-element;
the second polarized light after the light splitting process enters the second subelement.
18. A display device, comprising:
a display panel;
the light source device of any of claims 1-17, configured to provide backlighting to the display panel.
19. The display device according to claim 18, further comprising:
at least one light diffusing element located on at least one of a side of the display panel where the display surface is located and a back side of the display panel and configured to diffuse light emitted from at least one of the display panel and the light guide element.
20. The display device according to claim 19, further comprising:
and a light converging element positioned between the light guide element and the display panel and configured to converge the light emitted from the light guide element and then direct the converged light to the at least one light diffusing element.
21. A heads-up display, comprising:
the display device of any one of claims 18-20; and
the reflection imaging part is positioned on the light emitting side of the display device and is configured to reflect the light emitted by the display device to the observation area of the head-up display.
22. A transportation device comprising the heads-up display of claim 21.
23. The transit device of claim 22, wherein the reflective imaging portion comprises a windshield of the transit device.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202120370346.6U CN215769261U (en) | 2021-02-10 | 2021-02-10 | Light source device, display device, head-up display, and traffic equipment |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202120370346.6U CN215769261U (en) | 2021-02-10 | 2021-02-10 | Light source device, display device, head-up display, and traffic equipment |
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| CN215769261U true CN215769261U (en) | 2022-02-08 |
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