Dimming element, image source, head-up display device and vehicle

Abstract

The invention provides a dimming element, an image source, a head-up display device and a vehicle. The dimming element is used for adjusting the direction of emergent light of a backlight source in the head-up display device, the light element comprises a plurality of lenses, the central axes of the lenses are parallel to one another, and orthographic projections of different lenses on a reference plane perpendicular to the central axes are not overlapped; the lens comprises a first surface and a second surface which are oppositely arranged in the extension direction of the central axis of the lens, and the first surface is a non-rotational symmetry surface protruding in the direction away from the second surface and comprises a plurality of curved surface parts which are sequentially arranged around the central axis and connected. At least two adjacent curved surface parts arranged around the central shaft are in mirror symmetry, so that after emergent light of the backlight source sequentially passes through the second surface and the first surface, target illumination areas formed by the lenses on the target plane are not spaced. According to the embodiment of the invention, the backlight uniformity can be improved while the lighting effect is ensured.

Description

Technical Field

[0001] The present disclosure relates to the field of display technology, and in particular to a dimming element, an image source, a head-up display device, and a vehicle. Background Art

[0002] Head-up display (HUD) technology uses the principle of optical reflection to project light from an image source onto an imaging window (imaging board, windshield, etc.), where it is then reflected into the eye box to form a virtual image. This virtual image can display desired information, such as driving-related information like vehicle speed, to avoid distraction caused by looking down at the dashboard while driving, thereby improving driving safety and providing a better driving experience. In the image source, a backlight unit provides backlight for the display panel, which then converts the backlight into image light.

[0003] In the prior art, when improving the brightness distribution uniformity of the backlight unit on the display panel, the backlight efficiency is reduced. Summary of the Invention

[0004] The present disclosure aims to solve at least one of the technical problems existing in the prior art, and proposes a dimming element, an image source, a head-up display device, and a vehicle.

[0005] In a first aspect, the present disclosure provides a dimming element for adjusting the direction of the outgoing light of the backlight source in a head-up display device, characterized in that the dimming element includes a plurality of lenses, the central axes of the plurality of lenses are parallel to each other, and the orthographic projections of different lenses on a reference plane perpendicular to the central axis do not overlap with each other; wherein the lens includes a first surface and a second surface opposite to each other in the extension direction of its central axis, the first surface is a non-rotationally symmetrical surface convex in a direction away from the second surface, and includes a plurality of curved surface portions arranged and connected in sequence around the central axis; at least two adjacent curved surface portions arranged around the central axis are mirror-symmetrical, so that after the outgoing light of the backlight source passes through the second surface and the first surface in sequence, the target illumination areas formed by each lens on the target plane are not separated.

[0006] In some embodiments, the target illumination area is an axially symmetrical figure having multiple axes of symmetry, and the target illumination area is divided into multiple sub-areas by the multiple axes of symmetry; each adjacent two curved surface portions arranged around the central axis are mirror-symmetrical, and the sub-areas correspond one-to-one to the curved surface portions, and the sub-areas are the areas illuminated by the outgoing light of the corresponding curved surface portions on the target plane.

[0007] In some embodiments, the target illumination area is rectangular, and the first surface includes four of the curved surface portions; or, the target illumination area is square, and the first surface includes eight of the curved surface portions; or, the target illumination area is hexagonal, and the first surface includes six of the curved surface portions.

[0008] In some embodiments, the curved surface is a free-form surface, and is obtained by combining multiple free curves in a predetermined arrangement; wherein, the multiple free curves can be rotated to form multiple rotationally symmetrical surfaces, and the multiple circular illumination areas formed by the multiple rotationally symmetrical surfaces on the target plane are nested and concentric in sequence, and the innermost one of the multiple circular illumination areas is the inscribed circular area of ​​the target illumination area, and the outermost one of the multiple circular illumination areas is the circumscribed circular area of ​​the target illumination area.

[0009] In some embodiments, the target illumination area includes: a central sub-area and an edge sub-area surrounding the central sub-area, and the edge sub-areas corresponding to two adjacent lenses overlap.

[0010] In some embodiments, a plurality of the lenses are arranged in an array.

[0011] In a second aspect, the present disclosure provides an image source in a head-up display device, comprising: a backlight source, the backlight source comprising a plurality of backlight light sources; the above-mentioned dimming element, each of the lenses in the dimming element being arranged on the light-emitting side of one of the backlight light sources; and a display panel, the display panel being arranged on the light-emitting side of the target plane of the dimming element, and being used to convert the light emitted by the dimming element into image light and output it to a preset area.

[0012] In some embodiments, the display panel includes a plurality of pixels; the image source further includes a direction control element, which is disposed between the dimming element and the display panel and is used to adjust the direction of light emitted by the dimming element so that the main optical axis of at least part of the light emitted by the pixels converges to a target sub-area in the preset area, and the target sub-area is smaller than the preset area.

[0013] In some embodiments, the direction control element includes a convex lens, a concave lens, a Fresnel lens, or a combination of one or more thereof.

[0014] In some embodiments, the direction control element includes: a substrate, the substrate having a third surface and a fourth surface opposite to each other, the third surface being a curved surface, one of the third surface and the fourth surface facing the backlight source, and the other facing away from the backlight source; a Fresnel lens, the Fresnel lens being located on the third surface and being an integrally molded structure with the substrate.

[0015] In some embodiments, the third surface includes at least one of a convex surface, a concave surface, and a free-form surface; and the surface shape of the Fresnel lens includes at least one of a convex surface, a concave surface, and a free-form surface.

[0016] In some embodiments, the image source further includes: a plurality of optical microstructures, the plurality of optical microstructures being located on a side of the direction control element close to or away from the backlight source, and including: at least one focusing structure for converging the received light, and / or, at least one diverging structure for diverging the received light.

[0017] In some embodiments, the optical microstructure and the direction control element are an integrally formed structure; wherein, when the direction control element includes a substrate and a Fresnel lens arranged on a third surface of the substrate, the optical microstructure is located on a side of the substrate away from the Fresnel lens.

[0018] In some embodiments, the optical microstructure is a cylindrical lens structure, and a plurality of the optical microstructures are arranged side by side in the first direction.

[0019] In some embodiments, when the plurality of optical microstructures include a plurality of light-concentrating structures and a plurality of light-diverging structures, the light-concentrating structures and the light-diverging structures are alternately arranged in the first direction.

[0020] In some embodiments, the optical microstructure is a spherical lens structure, and a plurality of the optical microstructures are arranged in an array.

[0021] In some embodiments, when the plurality of optical microstructures include a plurality of light-concentrating structures and a plurality of light-diverging structures, the light-concentrating structures and the light-diverging structures are alternately arranged in both the row direction and the column direction.

[0022] In a third aspect, the present disclosure further provides a head-up display device, comprising: the above-mentioned image source; an output element, wherein the output element is used to receive the image light and output the image light to the preset area.

[0023] In a fourth aspect, the present disclosure further provides a vehicle, comprising: the above-mentioned head-up display device; and a reflective imaging element, wherein the reflective imaging element is used to reflect image light emitted by the head-up display device to the preset area.

[0024] In the above-mentioned solution provided by the embodiment of the present disclosure, the first surface of the lens is set to a non-rotationally symmetrical surface including multiple curved surface portions, and at least two adjacent curved surface portions are mirror-symmetrical, so that the lens can form a non-circular target illumination area, thereby making the target illumination areas of multiple lenses seamless, thereby improving the uniformity of the backlight. Moreover, since the lens of the present disclosure does not need to be cut, the light effect can be guaranteed. In addition, the lens in the embodiment of the present disclosure has a converging effect on light, but the outgoing light of the lens still has a certain divergence angle. Therefore, compared with the collimating lens that is rotationally symmetrical and forms a circular illumination area, the lens provided in the embodiment of the present disclosure that forms, for example, a rectangular or square illumination area has a larger light beam divergence angle, which can reduce the dispersion phenomenon, thereby improving the imaging effect of the head-up display device. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the following detailed description, they are used to explain the present disclosure but do not constitute a limitation of the present disclosure. In the accompanying drawings:

[0026] Figure 1 This is a schematic diagram of the application of the head-up display device provided in some examples.

[0027] Figure 2 Schematic diagram of a dimming element using a rotationally symmetric lens provided in some examples.

[0028] Figure 3 Schematic diagram of the cutting process for a rotationally symmetric lens.

[0029] Figure 4 Schematic diagram of a dimming element composed of multiple cut lenses provided in some examples.

[0030] Figure 5 A cross-sectional view of a dimming element provided in an embodiment of the present disclosure.

[0031] Figure 6 A three-dimensional diagram of a dimming element provided in an embodiment of the present disclosure.

[0032] Figure 7 A schematic diagram illustrating the principle of forming a target illumination area by the lens of a dimming element provided in an embodiment of the present disclosure.

[0033] Figures 8 to 10 Three top views of the first surface of the lens and schematic diagrams of three target illumination areas provided in an embodiment of the present disclosure.

[0034] Figure 11 A schematic diagram of the distribution of various target illumination areas provided in an embodiment of the present disclosure.

[0035] Figure 12A diagram illustrating the positional relationship between multiple circular illumination areas and a target illumination area determined when designing the surface shape of the curved surface portion according to an embodiment of the present disclosure.

[0036] Figure 13 A schematic diagram of the division of the target illumination area provided in an embodiment of the present disclosure.

[0037] Figure 14 A schematic diagram of an image source with the first structure provided in an embodiment of the present disclosure being applied in a vehicle.

[0038] Figure 15 A three-dimensional diagram of a first structure of a direction control element provided in an embodiment of the present disclosure.

[0039] Figure 16 A cross-sectional view of a second structure of a directional control element provided in an embodiment of the present disclosure.

[0040] Figure 17 A perspective view of a second structure of a direction control element provided in an embodiment of the present disclosure.

[0041] Figure 18 A three-dimensional diagram of a second structure of a directional control element provided in an embodiment of the present disclosure, cut along one direction.

[0042] Figure 19 A three-dimensional view of the second structure of the direction control element provided in an embodiment of the present disclosure after being cut along another direction.

[0043] Figure 20 A cross-sectional view of a third structure of a directional control element provided in an embodiment of the present disclosure.

[0044] Figure 21 A schematic diagram of light emission from a display panel provided in an embodiment of the present disclosure.

[0045] Figure 22 A schematic diagram of an image source of the second structure provided in an embodiment of the present disclosure.

[0046] Figure 23 A schematic diagram of an image source with a third structure provided in an embodiment of the present disclosure.

[0047] Figure 24 Three schematic diagrams of light adjustment using multiple optical microstructures provided in the embodiments of the present disclosure.

[0048] Figure 25 A first stereoscopic view of multiple optical microstructures provided in an embodiment of the present disclosure.

[0049] Figure 26 A second stereoscopic view of multiple optical microstructures provided in an embodiment of the present disclosure.

[0050] Figure 27 A schematic diagram of the arrangement of multiple optical microstructures provided in an embodiment of the present disclosure.

[0051] Figure 28 A schematic diagram of an image source with the fourth structure provided in an embodiment of the present disclosure.

[0052] Figure 29 A schematic diagram of an image source with the fifth structure provided in an embodiment of the present disclosure.

[0053] Figure 30 A schematic diagram of the structure of a head-up display device provided in an embodiment of the present disclosure.

[0054] Figure 31 A schematic diagram of a head-up display device and a windshield provided in an embodiment of the present disclosure. DETAILED DESCRIPTION

[0055] The following describes the specific embodiments of the present disclosure in detail with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present disclosure and are not intended to limit the present disclosure.

[0056] To make the purpose, technical solutions, and advantages of the embodiments of the present disclosure more clear, the technical solutions of the embodiments of the present disclosure will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the described embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0057] Unless otherwise defined, the technical or scientific terms used in the embodiments of the present disclosure should have the ordinary meaning understood by people with ordinary skills in the field to which the present disclosure belongs. The words "first", "second" and similar words used in the present disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, words such as "include" or "comprising" mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects.

[0058] As used herein, "parallel" and "perpendicular" include the conditions described and conditions similar to the conditions described, and the range of the similar conditions is within an acceptable deviation range, wherein the acceptable deviation range is determined by a person of ordinary skill in the art taking into account the measurement in question and the errors associated with the measurement of the specific quantity (i.e., the limitations of the measurement system). For example, "parallel" includes absolute parallelism and approximate parallelism, wherein the acceptable deviation range for approximate parallelism can be, for example, a deviation within 5°; "perpendicular" includes absolute perpendicularity and approximate perpendicularity, wherein the acceptable deviation range for approximate perpendicularity can also be, for example, a deviation within 5°.

[0059] In the description of the present disclosure, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present disclosure and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present disclosure.

[0060] Unless otherwise expressly specified or limited, terms such as "mounted," "connected," "connect," and "fixed" should be interpreted broadly. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediary; and internal communication between two components. Those skilled in the art will understand the specific meanings of these terms in this disclosure based on specific circumstances.

[0061] Figure 1 The following are application diagrams of head-up display devices provided in some examples. The head-up display device can be installed on vehicles and other transportation vehicles. Figure 1 As shown, the head-up display device includes an image source 100 for outputting image light. The image source 100 includes a backlight unit and a display panel 20 disposed on the light-emitting side of the backlight unit. The backlight unit is used to provide backlight for the display panel 20. The backlight unit may include a backlight source 10 and a dimming element 50 disposed on the light-emitting side of the backlight source 10. For example, the backlight source 10 may include multiple backlight light sources. The dimming element 50 includes multiple lenses, each lens corresponding to a backlight light source. Each backlight light source may include at least one backlight lamp 11, such as a light-emitting diode (LED). Each lens is used to adjust the emission direction of the corresponding backlight light source.

[0062] The display panel 20 is a liquid crystal display panel. The display panel 20 includes a plurality of pixel units, each of which includes a plurality of pixels. For example, each pixel unit includes a red pixel, a green pixel, and a blue pixel; for another example, each pixel unit includes a red pixel, a green pixel, a blue pixel, and a white pixel. The display panel 20 is used to convert the backlight provided by the backlight unit into image light. The vehicle's windshield 200 is used to reflect the image light to a predetermined area 300, so that when the observer's eyes are within the predetermined area 300, the observer can see the image formed by the image light. In this case, the observer sees a virtual image 400 formed by the windshield 200 in a reflective imaging manner. The observer can be a driver or a passenger, and can obtain the required vehicle information, such as driving speed, fuel consumption, etc., from the virtual image 400 in front of the observer's line of sight. It can also be other information, such as the image of a virtual rearview mirror or images of audio and video entertainment.

[0063] The aforementioned predetermined area 300 is the eyebox of the HUD device, specifically the area where the viewer's eyes are located and where the image displayed by the HUD is visible. The predetermined area 300 has a certain size. Even if the viewer's eyes are offset by a certain distance from the center of the predetermined area 300, such as vertically or horizontally, as long as they remain within the predetermined area 300, they can still see the image displayed by the HUD.

[0064] The lens 51 in the dimming element 50 is used to converge the light emitted by the backlight 11. For example, the lens 51 is a collimating lens used to collimate the light emitted by the backlight 11. Figure 2 As shown, the lens 51 is a rotationally symmetric lens. In this case, the illumination area formed by each lens 51 on the display panel 20 is circular, resulting in gaps between the circular illumination areas formed by each lens 51, which in turn causes uneven brightness distribution of the backlight on the display panel 20.

[0065] Currently, the problem of uneven backlight distribution is usually improved by cutting the rotationally symmetric lens. For example, Figure 3 The lens 51 in the figure is a rotationally symmetric lens. Figure 3 The lens 51 is cut by the quadrilateral cutting line C1, and the multiple cut lenses 51 are composed of Figure 4 The dimming element 50 in the embodiment of the present invention has a rectangular illumination area formed by the cut lens 51. Figure 3 The lens 51 is cut along the hexagonal cutting line C2 in FIG. 1 , and the illumination area formed by the cut lens 51 is a hexagon. However, when other conditions remain the same (for example, when the position, luminous angle, and power of the backlight 11 remain unchanged), cutting the lens 51 will result in a decrease in light efficiency.

[0066] In order to solve the above technical problems, the embodiment of the present disclosure provides a dimming element 50 for adjusting the direction of the emitted light of the backlight source 10 in the head-up display device. Figure 5 and Figure 6 As shown, the dimming element 50 includes a plurality of lenses 51 , the central axes of the plurality of lenses 51 are parallel to each other, and the orthographic projections of different lenses 51 on a reference plane perpendicular to the central axes do not overlap.

[0067] The central axis of the lens 51 refers to an axis passing through the optical center of the lens 51 and extending along the thickness direction of the lens 51 .

[0068] The lens 51 includes a first surface 511 and a second surface 512, which are opposed to each other along the extension direction of its central axis. The first surface 511 is a non-rotationally symmetrical surface that convexly projects away from the second surface 512. It is understood that a non-rotationally symmetrical surface is the opposite of a rotationally symmetrical surface. A rotationally symmetrical surface is a surface whose shape, after being rotated by any angle about its axis of symmetry, remains identical to its original shape. In other words, a rotationally symmetrical surface can be obtained by rotating a generatrix along an axis of symmetry passing through its vertex. When light passes through a rotationally symmetrical surface, the illumination area formed on the target plane is a circular area.

[0069] Figure 7 FIG. 5 shows a schematic diagram of the lens 51 forming the target illumination area 5A. Figures 8 to 10 FIG2 shows a top view of the first surface 511 of the lens 51 with different structures in the embodiment of the present disclosure and a target illumination area 5A formed by the lens 51. Figure 11 The distribution of multiple target illumination areas 5A is shown. Figures 7 to 10 As shown, the first surface 511 of the lens 51 includes a plurality of curved surface portions 5110 sequentially arranged and connected around the central axis. At least two adjacent curved surface portions 5110 arranged around the central axis are mirror-symmetrical, so that the outgoing light from the backlight 11 in the backlight source 10 forms a target illumination area 5A on the target plane S0 after passing through the second surface 512 and the first surface 511 in sequence. Figure 11 As shown, the target illumination areas 5A formed by the lenses 51 on the target plane S0 are not spaced apart.

[0070] Two of the plurality of curved surface portions 5110 may be mirror-symmetric, or the plurality of curved surface portions 5110 may be divided into multiple pairs, with two adjacent curved surface portions 5110 in each pair being mirror-symmetric, or any two adjacent curved surface portions 5110 may be mirror-symmetric. It will be understood that when two adjacent curved surface portions 5110 are mirror-symmetric, it means that the two curved surface portions 5110 are mirror-symmetric about a plane where their boundary line lies.

[0071] The target plane S0 is a plane at a certain distance from the lens 51, and the target plane S0 may be located on the side of the first surface 511 away from the second surface 512. Figure 7 As shown, the target illumination area 5A is the area on the target plane S0 illuminated by the light of the backlight 11 in the backlight source 10 after passing through the lens 51. The shape of the target illumination area 5A is non-circular. Figure 8 As shown, the target illumination area 5A is a rectangle; for example, Figure 9 As shown, the target illumination area 5A is a square; for example, Figure 10 As shown, the target illumination area 5A is a hexagon; of course, the target illumination area 5A may also be other non-circular shapes. Figure 11 FIG. 4 shows a situation where the edges of adjacent target illumination areas 5A touch each other but there is no gap; of course, in other examples, adjacent target illumination areas 5A may also overlap.

[0072] In the disclosed embodiment, the first surface 511 of the lens 51 is designed to include a plurality of non-rotationally symmetrical curved surface portions 5110, with at least two adjacent curved surface portions 5110 being mirror-symmetrical. This allows the lens 51 to form a non-circular target illumination area 5A. This allows the target illumination areas 5A of the multiple lenses 51 to be seamlessly spaced, thereby improving backlight uniformity. Furthermore, since the lens 51 of the disclosed embodiment does not require cutting, light efficiency is maintained.

[0073] In addition, in the embodiment of the present disclosure, the first surface 511 protrudes in a direction away from the second surface 512. Therefore, the first surface 511 has a converging effect on the light from the backlight source 10, wherein the area of ​​the target illumination area 5A is larger than the outer contour area of ​​the lens 51; the outer contour area refers to the area of ​​the orthographic projection of the lens 51 on a reference plane perpendicular to its central axis. In other words, the lens 51 in the embodiment of the present disclosure has a converging effect on light, but the light emitted by the lens 51 still has a certain divergence angle. Therefore, compared with a collimating lens that is rotationally symmetrical and forms a circular illumination area, the lens 51 provided in the embodiment of the present disclosure, which forms, for example, a rectangular illumination area or a square illumination area, has a larger light beam divergence angle, which can reduce dispersion and thereby improve the imaging effect of the head-up display device.

[0074] In some embodiments, as Figures 8 to 10As shown, the target illumination area 5A is an axisymmetric figure having multiple axes of symmetry, and the target illumination area 5A is divided into multiple sub-areas 5A0 by the multiple axes of symmetry. Each two adjacent curved surface portions 5110 arranged around the central axis are mirror-symmetrical, and the sub-areas 5A0 correspond one-to-one to the curved surface portions 5110. The sub-area 5A0 is the area illuminated by the outgoing light of the corresponding curved surface portion 5110 on the target plane S0. Since each two adjacent curved surface portions 5110 are mirror-symmetrical, when designing the surface shape of the first surface 511, it is sufficient to ensure that the illumination area of ​​a certain curved surface portion 5110 on the target plane S0 is a sub-area 5A0 of the required target illumination area 5A. Then, the surface shapes of the other curved surface portions 5110 can be obtained by mirror-symmetry. The illumination area formed by the first surface 511 composed of the curved surface portions 5110 is the target illumination area 5A.

[0075] In the first example, if Figure 8 As shown, the target illumination area 5A is a rectangle having two axes of symmetry. The rectangular target illumination area 5A can be divided into four sub-areas 5A0 by the two axes of symmetry. Accordingly, the first surface 511 of the lens 51 includes four curved surface portions 5110. Specifically, the four curved surface portions 5110 are a first curved surface portion 5111, a second curved surface portion 5112, a third curved surface portion 5113, and a fourth curved surface portion 5114. Each two adjacent curved surface portions 5110 arranged around the central axis are mirror-symmetrical. The overall surface shape composed of the first curved surface portion 5111 and the second curved surface portion 5112 is mirror-symmetrical to the overall surface shape composed of the third curved surface portion 5113 and the fourth curved surface portion 5114. The overall surface shape composed of the first curved surface portion 5111 and the fourth curved surface portion 5114 is also mirror-symmetrical to the overall surface shape composed of the second curved surface portion 5112 and the third curved surface portion 5113. When designing the surface shape, only the surface shape of the first curved surface portion 5111 can be designed so that its illumination area on the target plane S0 is one of the sub-areas 5A0. Then, the first curved surface portion 5111 is mirrored to obtain the second curved surface portion 5112, the third curved surface portion 5113 and the fourth curved surface portion 5114 which correspond one-to-one to the other three sub-areas 5A0 respectively.

[0076] In the second example, Figure 9As shown, the target illumination area 5A is a square having four axes of symmetry. The square target illumination area 5A can be divided into eight sub-areas 5A0 by the four axes of symmetry. Accordingly, the first surface 511 of the lens 51 includes eight curved surface portions 5110. Specifically, the eight curved surface portions 5110 are respectively the first curved surface portion 5111 to the eighth curved surface portion 5118. Every two adjacent curved surface portions 5110 arranged around the central axis are mirror-symmetrical. Moreover, the overall surface shape composed of the first curved surface portion 5111 and the second curved surface portion 5112 is mirror-symmetrical to the overall surface shape composed of the third curved surface portion 5113 and the fourth curved surface portion 5114; the overall surface shape composed of the fifth curved surface portion 5115 and the sixth curved surface portion 5116 is mirror-symmetrical to the overall surface shape composed of the seventh curved surface portion 5117 and the eighth curved surface portion 5118; the first curved surface portion 5111 is mirror-symmetrical to the overall surface shape composed of the first curved surface portion 5111 and the second curved surface portion 5112. The overall surface shape composed of the second curved surface portion 5112, the third curved surface portion 5113, and the fourth curved surface portion 5114 is mirror-symmetrical to the overall surface shape composed of the fifth curved surface portion 5115, the sixth curved surface portion 5116, the seventh curved surface portion 5117, and the eighth curved surface portion 5118. The overall surface shape composed of the first curved surface portion 5111, the second curved surface portion 5112, the seventh curved surface portion 5117, and the eighth curved surface portion 5118 is mirror-symmetrical to the overall surface shape composed of the third curved surface portion 5113, the fourth curved surface portion 5114, the fifth curved surface portion 5115, and the sixth curved surface portion 5116. When designing the surface shape, only the surface shape of the first curved surface portion 5111 can be designed so that its illumination area on the target plane S0 is one of the sub-areas 5A0. Then, the first curved surface portion 5111 is mirror-reversed to obtain the second curved surface portions 5112 to the eighth curved surface portion 5118, which correspond one-to-one to the other seven sub-areas 5A0.

[0077] In the third example, Figure 10As shown, the target illumination area 5A is a regular hexagon having three axes of symmetry. The regular hexagonal target illumination area 5A can be divided into six sub-areas 5A0 by the three axes of symmetry. Accordingly, the first surface 511 of the lens 51 includes six curved surface portions 5110. Specifically, the six curved surface portions 5110 are respectively a first curved surface portion 5111 to a sixth curved surface portion 5116. Each two adjacent curved surface portions 5110 arranged around the central axis are mirror-symmetrical. Furthermore, the overall surface shape composed of the first curved surface portion 5111 and the second curved surface portion 5112 is mirror-symmetrical to the overall surface shape composed of the third curved surface portion 5113 and the fourth curved surface portion 5114. The overall surface shape composed of the first curved surface portion 5111, the second curved surface portion 5112, and the third curved surface portion 5113 is mirror-symmetrical to the overall surface shape composed of the fourth curved surface portion 5114, the fifth curved surface portion 5115, and the sixth curved surface portion 5116. When designing the surface shape, only the surface shape of the first curved surface portion 5111 can be designed so that its illumination area on the target plane S0 is the first sub-area 5A0. Then, the first curved surface portion 5111 is mirrored to obtain the second curved surface portion 5112 to the sixth curved surface portion 5116 corresponding one-to-one to the other five sub-areas 5A0.

[0078] In some embodiments, the curved surface 5110 is a free-form surface formed by combining multiple free-form curves in a predetermined arrangement. The multiple free-form curves can be rotated to form multiple rotationally symmetric planes. The multiple circular illumination areas formed by the multiple rotationally symmetric planes on the target plane S0 are nested and concentric. The innermost of the multiple circular illumination areas is the inscribed circular area of ​​the target illumination area 5A, and the outermost of the multiple circular illumination areas is the circumscribed circular area of ​​the target illumination area 5A.

[0079] The inscribed circular area refers to the largest circular area that does not exceed the target illumination area 5A; the circumscribed circular area refers to the smallest circular area that can completely cover the target illumination area 5A. Figure 12 As shown, taking the target illumination area 5A as a square as an example, when designing the surface shape of the curved surface 5110, the circumscribed circular area of ​​the target illumination area 5A can be determined first (e.g. Figure 12 The circular illumination area 5A1 is shown in FIG), and then the center of the circular illumination area 5A1 is fixed and the diameter is gradually reduced until the inscribed circular area of ​​the target illumination area 5A is obtained (as shown in FIG. Figure 12), a plurality of concentrically nested circular illumination areas 5A1-5An are obtained. Next, n rotationally symmetric surfaces are determined that can form each of the n circular illumination areas 5A1-5An. A free-form curve from the center to the edge of each rotationally symmetric surface is taken and sequentially combined to obtain a curved surface portion 5110. The disclosed embodiments do not limit the surface design process of the rotationally symmetric surfaces, as long as the rotationally symmetric surfaces can form the corresponding target illumination area 5A on the target plane S0.

[0080] The above-mentioned design method can conveniently obtain the surface shape of the curved surface portion 5110 , and then the surface shape of the entire first surface 511 ; and is beneficial to improving the brightness uniformity of the target illumination area 5A.

[0081] It is understood that the greater the number of circular illumination areas 5A1 to 5An, the greater the number of free curves, and the more accurate the shape of the curved surface portion 5110. In practical applications, the number of free curves can be determined according to actual needs.

[0082] It should be noted that the above-mentioned surface design process of the curved surface portion 5110 is described by taking the example of first determining the circumscribed circular area. It is also possible to first determine the inscribed circular area of ​​the target illumination area 5A, and then fix the center of the inscribed circular area, and gradually expand the diameter until the circumscribed circular area of ​​the target illumination area 5A is obtained, thereby obtaining multiple concentrically nested circular illumination areas A1~An.

[0083] For target illumination areas 5A of other shapes (eg, rectangle, hexagon, etc.), the above-mentioned design method can be used to design the surface shape of the curved surface portion 5110 .

[0084] In order to prevent the target illumination area 5A from having a bright center and dark edges, in some embodiments of the present disclosure, Figure 13 As shown, the target illumination area 5A includes: a central sub-area 5Aa and an edge sub-area 5Ab surrounding the central sub-area 5Aa. The edge sub-areas 5Ab corresponding to two adjacent lenses 51 overlap. This setting can improve the edge brightness of the target illumination area 5A, thereby improving the brightness uniformity of the entire target illumination area 5A.

[0085] For example, the width of the edge sub-region 5Ab is 1 / 3 to 2 / 3 of the width of the middle sub-region 5Aa.

[0086] In some embodiments, the target illumination area 5A formed by the first surface 511 of the lens 51 on the target plane S0 is rectangular or square. Figure 6In other embodiments, the target illumination area 5A formed by the first surface 511 of the lens 51 on the target plane S0 is hexagonal, and the lenses 51 can be arranged in multiple rows, with adjacent rows of lenses 51 arranged in a staggered manner.

[0087] In some embodiments, as Figure 5 and Figure 6 As shown, the second surface 512 of the lens 51 is a plane, and multiple lenses 51 can be arranged on a substrate 52, with the second surface 512 of the lens 51 located on the substrate 52, and the first surface 511 protruding in a direction away from the substrate 52. The lens 51 and the substrate 52 can be an integrally formed structure or a separate structure.

[0088] The embodiment of the present disclosure also provides an image source 100 in a head-up display device, such as Figure 14 As shown, the image source 100 includes: a backlight source 10, a display panel 20 and the dimming element 50 in the above embodiment.

[0089] The backlight source 10 includes a plurality of backlight light sources, each of which may include at least one backlight lamp 11. The backlight source 10 is used to provide backlight for the display panel 20. The backlight lamp 11 may specifically be an electroluminescent element, such as a light emitting diode (LED), an organic light emitting diode (OLED), a mini light emitting diode (MiniLED), a micro light emitting diode (MicroLED), a cold cathode fluorescent lamp (CCFL), an electroluminescent display (ELD), an LED cold light source (Cold LED Light, CLL), an electroluminescent (EL), an electron emission (Field Emission Display, FED), a tungsten halogen lamp, or a metal halide lamp, etc., and the embodiments of the present disclosure are not limited thereto.

[0090] Each lens 51 in the dimming element 50 corresponds to a backlight light source, and each lens 51 is arranged on the light-emitting side of the corresponding backlight light source.

[0091] The display panel 20 is positioned on the light-emitting side of the target plane S0 of the dimming element 50, and is configured to convert the light emitted by the dimming element 50 into image light, which is then output to a predetermined area. The light-incident surface of the display panel 20 can serve as the target plane S0, meaning that the illumination areas formed on the display panel 20 by the lenses 51 in the dimming element 50 are completely separated. Alternatively, the light-incident surface of the display panel 20 can be located on the side of the target plane S0 away from the dimming components and spaced apart from the target plane S0. In this case, the illumination areas formed on the display panel 20 by the lenses 51 in the dimming element 50 are also completely separated.

[0092] The display panel 20 includes a plurality of pixel units, each of which may include a plurality of pixels. For example, each of the pixel units includes a red pixel, a green pixel, and a blue pixel.

[0093] The display panel 20 may include an array substrate, a color filter substrate, and a liquid crystal layer located therebetween, which are arranged relative to each other. The color filter substrate may include a plurality of color filter portions, each corresponding to a pixel. For example, the plurality of color filter portions include a red filter portion corresponding to a red pixel, a green filter portion corresponding to a green pixel, and a blue filter portion corresponding to a blue pixel. In some embodiments, the spectrum of the backlight matches the transmittance spectrum of the color filter substrate, so that more light in the backlight can pass through the display panel 20 and be converted into image light, thereby improving the transmittance of the backlight, reducing the proportion of the backlight converted into heat energy by the display panel 20, reducing the temperature rise of the display panel 20, and thereby extending the service life of the display panel 20.

[0094] It should be noted that matching the backlight spectrum with the color filter substrate's transmittance spectrum means that the peaks in the backlight's luminescence spectrum correspond one-to-one with the peaks in the color filter substrate's transmittance spectrum, and that the two corresponding peaks reside in the same or substantially the same wavelength bands. For example, the red filter is configured to transmit light within the wavelength range of 625-740 nm, the green filter is configured to transmit light within the wavelength range of 492-577 nm, and the blue filter is configured to transmit light within the wavelength range of 440-475 nm. In other words, the color filter substrate's transmittance spectrum has three first peaks, located in the 625-740 nm, 492-577 nm, and 440-475 nm wavelength bands, respectively. In this case, the backlight's luminescence spectrum also includes three second peaks, located in the same wavelength bands as the aforementioned three, or with at least 70% overlap, or the wavelength bands corresponding to the three second peaks are respectively within the wavelength bands corresponding to the aforementioned three first peaks.

[0095] In the disclosed embodiment, the illumination areas formed by each lens 51 in the dimming element 50 on the display panel 20 are uniform, thereby improving the uniformity of the brightness of the light received at each position on the display panel 20, thereby improving imaging uniformity. This also facilitates the design of the virtual image indicator (UI) in the head-up display device. Furthermore, compared to collimating lenses, each lens 51 in the disclosed embodiment has a lower degree of light dispersion, thereby improving the imaging quality of the head-up display device.

[0096] In some embodiments, as Figure 14 As shown, the image source 100 may further include a direction control element 30, which is disposed between the dimming element 50 and the display panel 20 and is used to adjust the direction of the light emitted by the dimming element 50 so that the main optical axis of at least part of the pixel emitted light converges to a target area 301 in the preset area 300, and the target area 301 is smaller than the preset area 300.

[0097] The target area 301 is an area within the preset area 300. Preferably, the center of the preset area 300 is located within the target area 301. For example, the center of the target area 301 coincides with the center of the preset area 300. The shapes of the target area 301 and the preset area 300 may be the same or different.

[0098] By setting a direction control element 30 between the dimming element 50 and the display panel 20, the light of the pixel can be concentrated into the target area 301 closer to the center of the preset area 300, so that a light spot as small as possible can be diffused to cover the preset area 300, so that the light can be concentrated as much as possible, the imaging brightness is higher, and the observer can see a brighter image.

[0099] Preferably, the direction control device 30 is used to make the main optical axes of the light emitted by all pixels converge to the target area 301 in the preset area 300, so that when the observer's eyes are in the preset area 300, they can receive all the light emitted by all pixels and see the complete image.

[0100] In some embodiments, the direction control element 30 may be a curved lens, such as a convex lens or a concave lens.

[0101] like Figures 15 to 17 As shown, the direction control element 30 may include a substrate 31 and a Fresnel lens 32. The substrate 31 includes a third surface 31a and a fourth surface 31b that are opposed to each other in the thickness direction thereof. One of the third surface 31a and the fourth surface 31b is a surface of the substrate 31 facing the backlight source 10, and the other is a surface away from the backlight source 10. The Fresnel lens 32 is disposed on the third surface and is integrally formed with the substrate 31.

[0102] In one configuration of the direction control element 30, as Figure 15 As shown, the third surface 31a can be a plane, and the direction control element 30 as a whole is equivalent to a plane Fresnel lens.

[0103] In order to not affect the light effect, the direction control element 30 has a smaller thickness, such as Figures 16 to 19 As shown, in another structure of the direction control element 30, the third surface 31a is a curved surface. In this case, the base 31 is equivalent to a curved lens, thereby adjusting the direction of the light. At the same time, the Fresnel lens 32 provided on the third surface 31a can also play a role in adjusting the direction of the light. It is equivalent to superimposing the Fresnel lens 32 on the curved lens, using two lenses to simultaneously adjust the direction of the light. For the same focal length, Figure 16 The direction control element 30 has a smaller thickness than the direction control element 30 using a convex lens or a concave lens, thereby facilitating the installation of the direction control element 30 into the image source 100; and compared to the plane Fresnel lens, Figure 16 The maximum depth of the Fresnel teeth in the directional control element 30 shown is small, which makes processing easier and more cost-effective, and improves the light efficiency.

[0104] In some embodiments, the shape of the direction control element 30 can be the same as that of the display panel 20. For example, both the direction control element 30 and the display panel 20 are rectangular. It should be noted that the shape of the direction control element 30 refers to the shape of the orthographic projection of the direction control element 30 on the plane where the display panel 20 is located.

[0105] In some embodiments, the direction control element 30 can be used to adjust light in one or two directions so that the principal optical axis of the light emitted by the pixel can be incident on the target area 301. For example, the two directions mentioned above are the length and width of the display panel 20. The surface shapes of the third surface 31a and the Fresnel lens 32 can be flexibly designed according to actual needs. The third surface 31a can include at least one of a convex surface (i.e., a surface that curves away from the fourth surface 31b), a concave surface (i.e., a surface that curves toward the fourth surface 31b), and a free-form surface. The surface shape of the Fresnel lens 32 includes at least one of a convex surface, a concave surface, and a free-form surface. That is, the third surface 31a can be convex or concave, or a combination of different surface shapes (e.g., a combination of convex and concave surfaces); the surface shape of the Fresnel lens 32 can be convex or concave, or a combination of different surface shapes (e.g., a combination of convex and concave surfaces), as long as their equivalent focal lengths meet design requirements.

[0106] Figure 16 and Figure 17In the figure, only the third surface 31a is taken as an example to illustrate the direction control element 30. Figure 18 As shown, the base 31 is longitudinally cut along the length direction of the base 31 to obtain a first longitudinal section, and the boundary line between the first longitudinal section and the third surface 31a is bent toward the fourth surface 31b; Figure 19 As shown, the base 31 is longitudinally cut along the width direction of the base 31 to obtain a second longitudinal section, and the boundary line between the second longitudinal section and the third surface 31a is curved toward the fourth surface 31b; wherein, the curvature of the boundary line between the first longitudinal section and the third surface 31a and the curvature of the boundary line between the second longitudinal section and the third surface 31a can be the same or different.

[0107] In some embodiments, the Fresnel lens 32 includes a plurality of Fresnel teeth on the third surface 31a. The Fresnel teeth have a width on the micrometer scale, for example, less than 300 micrometers. This prevents obvious bright and dark fringes from appearing in the image formed by the head-up display device, improves the image detail, and thus enhances the viewer's visual experience. Furthermore, the Fresnel teeth have a width less than 150 micrometers, further enhancing the image detail.

[0108] The Fresnel teeth of the Fresnel lens 32 are annular in shape, with multiple Fresnel teeth nested in sequence. The width of the Fresnel teeth is the width of the annular structure. In other examples, the Fresnel teeth on the third surface 31a can be other non-annular free-form Fresnel surfaces with varying inclinations.

[0109] like Figure 20 As shown, in other embodiments, the direction control element 30 includes, in addition to the substrate 31 and the Fresnel lens 32 disposed on the third surface 31a of the substrate 31, a Fresnel lens 32 disposed on the fourth surface 31b of the substrate 31. The fourth surface 31b of the substrate 31 is a curved surface, and the Fresnel lens 32 on the fourth surface 31b is an integrally formed structure with the substrate 31.

[0110] exist Figure 20 In the figure, the third surface 31a and the fourth surface 31b of the base 31 are both curved surfaces, thereby enhancing the base 31's ability to regulate the direction of light. At the same time, the Fresnel lenses 32 on the third surface 31a and the fourth surface 31b can also regulate the direction of light. This is equivalent to superimposing two Fresnel lenses on a curved lens, using three lenses to regulate the direction of light simultaneously. For the same focal length, Figure 20 Compared with the direction control element 30 using a convex lens or a concave lens, the thickness of the direction control element 30 can be further reduced; and compared with the flat Fresnel lens, Figure 20 The maximum depth of the Fresnel teeth in the direction control element 30 is further reduced, thereby further improving the light efficiency.

[0111] Figure 20 The example in which the fourth surface 31b is concave is merely shown. In actual applications, the surface shape of the fourth surface 31b and the Fresnel lens 32 on the fourth surface 31b can be flexibly designed based on actual needs. The fourth surface 31b can include at least one of a convex surface (i.e., a surface that curves away from the third surface 31a), a concave surface (i.e., a surface that curves toward the third surface 31a), and a free-form surface. The surface shape of the Fresnel lens 32 on the fourth surface 31b can include at least one of a convex surface, a concave surface, and a free-form surface. That is, the fourth surface 31b can be convex, concave, or a combination of different surface shapes (e.g., a combination of convex and concave surfaces). The surface shape of the Fresnel lens 32 on the fourth surface 31b can be convex, concave, or a combination of different surface shapes (e.g., a combination of convex and concave surfaces).

[0112] In some embodiments, the Fresnel lens 32 on the fourth surface 31b includes a plurality of Fresnel teeth, each having a micron-scale width. For example, the Fresnel teeth on the fourth surface 31b are less than 300 microns wide. This prevents obvious bright and dark fringes from appearing in the image formed by the head-up display device, improves the image detail, and thus enhances the viewer's visual experience. Furthermore, the Fresnel teeth on the fourth surface 31b are less than 150 microns wide, further enhancing the image detail.

[0113] The Fresnel teeth of the Fresnel lens 32 on the fourth surface 31b are annular in shape, with multiple Fresnel teeth nested in sequence. The width of the Fresnel teeth is the width of the annular structure. In other examples, the Fresnel teeth on the fourth surface 31b can be other non-annular free-form Fresnel surfaces with varying inclinations.

[0114] When the head-up display device is used in a vehicle, the image light emitted from the display panel 20 is finally reflected by the windshield 200 (see FIG. Figure 14 ) is reflected to the preset area 300, and the windshield 200 is often not a plane, so the outgoing light of the display panel 20 has asymmetry. Figure 21 , where the two pixels at positions A and B are symmetrical about the central axis L0 of the display panel 20, while the principal optical axis L1 of the light emitted by the pixel at position A is not symmetrical with the principal optical axis L2 of the light emitted by the pixel at position B. Accordingly, the cross-sectional profile of the equivalent lens formed by the substrate 31 of the direction control device 30 and the Fresnel lens on the substrate 31 is non-circular. The cross-sectional profile of the equivalent lens is a cross-section perpendicular to the central axis.

[0115] In some embodiments, as Figure 22 and Figure 23As shown, image source 100 may further include a plurality of optical microstructures 61, located on the side of direction control element 30 that is close to or away from backlight source 10. Optical microstructures 61 are used to adjust the divergence angle of light. Optionally, optical microstructures 61 are larger than 1 micron. For example, the width of optical microstructures 61 is greater than 1 micron.

[0116] The plurality of optical microstructures 61 may include at least one light-concentrating structure 611 and / or at least one light-diverging structure 612. The light-concentrating structure 611 includes a light-concentrating surface 611a for converging the received light, and the light-diverging structure 612 includes a light-diverging surface 612a for diverging the received light. Figure 24 As shown in FIG. 6( a ), each optical microstructure 61 is a light-collecting structure 611; or Figure 24 As shown in FIG. 6( b ), each optical microstructure 61 is a divergent structure 612; or Figure 24 As shown in FIG. 5( c ), a portion of the multiple optical microstructures 61 are light-concentrating structures 611 , and another portion are light-diverging structures 612 .

[0117] like Figure 24 As shown, the light is converged after being incident on the focusing surface of the focusing structure 611, and the light gradually diverges on the side of the focal plane S2 of the focusing structure away from the focusing structure; the light is diverged after being incident on the divergent surface 612a of the divergent structure 612, and on the first plane S1 on the side of the focal plane S2 away from the direction control element 30 (the distance between the first plane S1 and the focal plane S2 is greater than or equal to the preset distance d0), the light can achieve a better diffusion effect.

[0118] By setting up multiple optical microstructures 61, the light can be diffused so that the light spot formed by the light emitted from the pixel is diffused to the entire preset area 300 as much as possible, so that the observer's eyes can see the complete virtual image 400 at any position in the preset area 300.

[0119] In some embodiments, the plurality of optical microstructures 61 and the direction control element 30 are integrally formed, thereby simplifying the overall structure of the image source 100. Figure 22 As shown, the direction control element 30 is a curved lens, and the plurality of optical microstructures 61 are located on the side of the direction control element 30 away from the backlight source 10; or, the optical microstructures 61 are located on the side of the direction control element 30 close to the backlight source 10. Figure 24 As shown, when the direction control element 30 includes the aforementioned substrate 31 and the Fresnel lens 32 located on the third surface of the substrate 31 , the optical microstructure 61 is located on a side of the substrate 31 away from the Fresnel lens 32 .

[0120] When the multiple optical microstructures 61 are located on the side of the direction control element 30 away from the backlight 10, the direction control element 30 and the optical microstructures 61 first focus the light emitted by the dimming element 50 and then diffuse it. When the multiple optical microstructures 61 are located on the side of the direction control element 30 closer to the backlight 10, the direction control element 30 and the optical microstructures 61 first diffuse the light emitted by the dimming element 50 and then focus it. To control the light in a more directional manner, a method of focusing light first and then diffusing it can be adopted, that is, the multiple optical microstructures 61 are located on the side of the direction control element 30 away from the backlight 10.

[0121] like Figure 25 As shown, in some embodiments, the optical microstructure 61 is a cylindrical lens structure, with multiple optical microstructures 61 arranged side by side in a first direction, and each optical microstructure 61 extending along a second direction. For example, the first direction is perpendicular to the second direction. In this case, the optical microstructure 61 only diffuses light in the first direction.

[0122] It should be noted that, from Figure 24 It can be seen that for a beam of light incident parallel to the second surface 51231b, the beam of light will be diverged by the optical microlens 61 in at least one direction. For example, when a single optical microlens 61 is a cylindrical lens structure and the cylindrical lens structure extends along the second direction, the optical microlens 33 diverges the incident light in the first direction, and the maximum offset angle between the main axis of the outgoing light and the incident light in the first direction is the diffusion angle of the optical microlens 33 on the light in the first direction.

[0123] It should also be noted that the aforementioned first direction can be the length direction of the direction control element 30, and the second direction can be the width direction of the direction control element 30; or the first direction can be the width direction of the direction control element 30, and the second direction can be the length direction of the direction control element 30; or the first direction can intersect with both the length direction and the width direction of the direction control element 30, and the second direction can intersect with both the length direction and the width direction of the direction control element 30.

[0124] When the optical microstructures 61 utilize cylindrical lens structures, each optical microstructure 61 can be a concentrating structure 611; alternatively, each optical microstructure 61 can be a diverging structure 612; alternatively, a portion of the multiple optical microstructures 61 can be concentrating structures 611, while another portion can be diverging structures 612. When the multiple optical microlenses 61 include both concentrating structures 611 and diverging structures 612, the concentrating structures 611 and the diverging structures 612 are alternately arranged in the first direction, thereby achieving a more uniform light diffusion effect at different positions of the direction control element 30 in the first direction. Furthermore, the concentrating structures 611 and the diverging structures 612 can be closely arranged, thereby forming a smooth, wavy surface on the surface of the auxiliary diffusing element 60. This allows each position of the direction control element 30 to diffuse light, and the transition between the two cylindrical lens structures is smoother, thereby ensuring that the transition can also reliably adjust and diffuse the light.

[0125] In some examples, the plurality of optical microlenses 61 may be arranged axially symmetrically about a first axis of symmetry and / or a second axis of symmetry, where the first axis of symmetry is an axis passing through the geometric center of the direction control element 30 and extending along a first direction, and the second axis of symmetry is an axis passing through the geometric center of the direction control element 30 and extending along a second direction. This arrangement can achieve more uniform light dispersion at different locations on the direction control element 30, thereby improving imaging uniformity of the head-up display device.

[0126] In other embodiments, Figure 26 As shown, the optical microstructure 61 is a spherical lens structure, and multiple optical microstructures 61 are arranged in an array. In this case, the optical microstructure 61 can diffuse light in both the row and column directions. For example, by parameterizing the spherical lens structure, the optical microstructure 61 can achieve a light diffusion angle of 20°*5°, i.e., the optical microstructure 61 diffuses light at a 20° angle in the row direction and a 5° angle in the column direction.

[0127] For example, the row direction may be the length direction of the direction control element 30, and the column direction may be the width direction of the direction control element 30; alternatively, the row direction may be the width direction of the direction control element 30, and the column direction may be the length direction of the direction control element 30; or alternatively, both the row direction and the column direction may intersect with the length direction of the direction control element 30. In this way, the divergence angle of the light can be adjusted in both directions.

[0128] When the optical microstructure 61 adopts a spherical lens structure, each optical microstructure 61 can be a light-concentrating structure 611; or, each optical microstructure 61 can be a diverging structure 612; or, a portion of the optical microstructures 61 in the plurality of optical microlenses 61 can be light-concentrating structures 611, and another portion of the optical microlenses 61 can be diverging structures 612. When the plurality of optical microlenses 61 include both a plurality of light-concentrating structures 611 and a plurality of diverging structures 612, as shown in FIG. Figure 27 As shown, the focusing structures 611 and the diverging structures 612 are alternately arranged in both the row and column directions, so that different positions of the direction control element 30 have a more uniform light diffusion effect. Furthermore, the focusing structures 611 and the diverging structures 612 can be closely arranged, so that each position of the auxiliary diffusion element 60 can diffuse the light. This makes the transition between the two spherical lens structures smoother, thereby ensuring that the transition position can also reliably adjust and diffuse the light.

[0129] It should be noted that Figure 27 The blocks in FIG. 6 do not represent the shapes of the light-concentrating structure 611 and the light-diverging structure 612 .

[0130] Optional, Figure 26 The multiple optical microstructures 61 shown may be centrally symmetrical, so that the light diffusion at different positions of the direction control element 30 is more uniform, thereby improving the imaging uniformity of the head-up display device.

[0131] In some embodiments, as Figure 28 As shown, image source 100 also includes a homogenizing and dispersing element 40, disposed between direction control element 30 and display panel 20, for homogenizing received light. Homogenizing and dispersing element 40 may include multiple homogenizing structures configured to scatter and / or diffract light, thereby dispersing the light. The homogenizing structures are smaller than 1 micron, thereby ensuring more uniform brightness on display panel 20.

[0132] The homogenizing and dispersing element 40 can specifically be a scattering optical element, such as a light homogenizer or a diffuser; the homogenizing structure is the scattering particles in the scattering optical element. Alternatively, the homogenizing and dispersing element 40 can be a diffractive optical element (DOE) that has better control over the diffusion effect. When light passes through a scattering optical element such as a light homogenizer, it will be scattered. The light will be transmitted to many different angles and a small amount of diffraction will occur, but the scattering of light plays a major role. The diffractive optical element, by designing a specific microstructure on the surface, mainly plays a light expansion role through diffraction, forming a controllable size and shape of the light spot.

[0133] In some embodiments, as Figure 29As shown, the image source 100 may further include a polarization control element 24. The display panel 20 includes a first polarizer 21, a liquid crystal layer 23, and a second polarizer 22.

[0134] The first polarizer 21 and the second polarizer 22 are disposed on either side of the liquid crystal layer 23, with the first polarizer 21 positioned between the liquid crystal layer 23 and the backlight source 10. The first polarizer 21 is configured to transmit a first linearly polarized light beam, while the second polarizer 22 is configured to transmit a second linearly polarized light beam, the polarization direction of the second linearly polarized light beam being perpendicular to that of the first linearly polarized light beam. A polarization control element 24 is disposed between the backlight source 10 and the first polarizer 21. The polarization control element 24 is configured to transmit the first linearly polarized light beam and reflect or absorb the second linearly polarized light beam.

[0135] The display panel 20 may further include a first substrate and a second substrate (not shown in the figure), and the liquid crystal layer 23 is located between the first substrate and the second substrate, wherein the first polarizer 21 may be located on the side of the first substrate away from the liquid crystal layer 23, and the second polarizer 22 may be located on the side of the second substrate away from the liquid crystal layer 23.

[0136] The liquid crystal layer 23 of the display panel 20 is provided with polarizers with perpendicular polarization states, namely, a first polarizer 21 and a second polarizer 22, on opposite sides thereof. First linearly polarized light can pass through the first polarizer 21, and second linearly polarized light can pass through the second polarizer 22, with the polarization direction of the first linearly polarized light being perpendicular to the polarization direction of the second linearly polarized light. Since the light emitted by the backlight source 10 is generally unpolarized light, approximately 50% of the light energy is absorbed by the first polarizer 21. This portion of light energy causes the display panel 20 to heat up, thereby reducing the service life of the display panel 20. In the disclosed embodiment, a polarization control element 24 is provided between the backlight source 10 and the first polarizer 21. This polarization control element 24 is capable of transmitting the first linearly polarized light and reflecting or absorbing the second linearly polarized light, so that only the first linearly polarized light reaches the first polarizer 21. This prevents the first polarizer 21 from absorbing the second linearly polarized light, preventing the display panel 20 from absorbing heat, and thereby extending the service life of the display panel 20. Among them, if the second linearly polarized light can be absorbed by the polarization control element 24, it is only necessary to ensure that the polarization control element 24 is separated from the display panel 20 by a certain distance; in addition, if the polarization control element 24 can reflect the second linearly polarized light, the reflected second linearly polarized light can be reflected again to the polarization control element 24 through the reflection effect of other components, and part of the light can be converted into the first linearly polarized light, so that more light can be used for imaging of the display panel 20, thereby improving the utilization rate of light.

[0137] Optionally, the polarization control element 24 is a reflective polarizing reflective film, which can be specifically DBEF (Dual Brightness Enhancement Film), BEF, a photonic crystal with polarization and incident angle selective transmittance, etc., and when the polarization control element 24 is capable of reflecting the second linearly polarized light, the polarization control element 24 can be attached to the surface of the display panel 20 facing the backlight source 10.

[0138] In some embodiments, the polarization control element 24 and the homogenizing and dispersing element 40 are two different elements. In other embodiments, the homogenizing and dispersing element 40 itself has the function of reflecting or absorbing the second linearly polarized light. In this case, the homogenizing and dispersing element 40 can be used as the polarization control element 24, and there is no need to set up an additional polarization control element 24.

[0139] The present disclosure also provides a head-up display device, such as Figure 30 As shown, the head-up display device includes the image source 100 and the output element 500 in the above embodiment. The output element 500 is used to receive the image light output by the image source 100 and output the image light to the preset area 300.

[0140] In some embodiments, as Figure 30 As shown, the head-up display device may further include a housing 600 , wherein the image source 100 and the output element 500 are both located in the housing 600 , thereby protecting the image source 100 and the output element 500 . The housing 600 has an opening 601 , so that image light can be emitted from the opening 601 .

[0141] In some embodiments, the output element 500 may include a magnifying element 501. This magnifying element 501 can enable the head-up display device to have a longer imaging distance and a larger imaging size. For example, the imaging distance and imaging size can be changed by changing the magnification of the magnifying element 501. The magnification can be changed by adjusting parameters such as the curvature of the magnifying element 501.

[0142] In some embodiments, the magnifying element 501 may be a curved reflector. Optionally, the curved reflector is a concave reflector, that is, a reflector having a concave curved surface. If the curved reflector is a concave reflector, if the optical distance between the image source 100 and the concave reflector is less than the focal length of the concave reflector, the concave reflector forms an erect, magnified virtual image based on the image output by the image source 100. For example, according to the imaging properties of a concave reflector, if the optical distance between the image source 100 and the concave reflector is less than the focal length of the concave reflector (i.e., the image source 100 is within one focal length of the concave reflector), the image distance of the concave reflector increases as the optical distance between the image source 100 and the concave reflector increases. In other words, the greater the optical distance between the image source 100 and the concave reflector, the greater the distance between the observer and the virtual image 400 they observe.

[0143] Optionally, the curved reflector is a free-form reflector, that is, the reflective surface is a free-form reflector, or the reflective surface does not have rotational symmetry, so as to improve the imaging quality of the head-up display device.

[0144] In other optional embodiments, the amplifying element 501 may be an optical waveguide or a holographic optical element.

[0145] like Figure 30 As shown, the output element 500 is not limited to including only the amplifying element 501, but may also include a plane reflector 502, through which the optical path of the image light propagation is adjusted, thereby reducing the volume of the head-up display device.

[0146] The present disclosure also provides a vehicle comprising the head-up display device and the reflective imaging element in the above embodiment. Figure 31 As shown, the reflective imaging element is a windshield 200, which is used to reflect the image light emitted by the head-up display device to a preset area 300. The windshield 200 has a semi-transmissive and semi-reflective property, so that the image light emitted by the head-up display device can be reflected by the windshield 200 to the preset area 300. At the same time, the light outside the vehicle can also pass through the windshield 200 to reach the preset area 300, so that when the observer's eyes are located in the preset area 300, they can see the image formed by the head-up display device and the scene outside the vehicle at the same time. The "semi-transmissive and semi-reflective" in the embodiment of the present disclosure means that the windshield 200 can transmit and reflect light, and is not limited to transmitting 50% of the light and reflecting 50% of the light. For example, the transmittance of visible light is greater than or equal to 70%.

[0147] It is understood that the above embodiments are merely exemplary embodiments for illustrating the principles of the present disclosure, and the present disclosure is not limited thereto. Those skilled in the art may make various modifications and improvements without departing from the spirit and substance of the present disclosure, and such modifications and improvements are also considered to be within the scope of protection of the present disclosure.

Claims

1. A dimming element for adjusting the direction of light emitted from a backlight source in a head-up display device, characterized in that: The dimming element includes a plurality of lenses, wherein central axes of the plurality of lenses are parallel to each other, and orthographic projections of different lenses on a reference plane perpendicular to the central axes do not overlap with each other; In which, the lens includes a first surface and a second surface opposite to each other in the extension direction of its central axis, the first surface is a non-rotationally symmetrical surface convex in the direction away from the second surface, and includes a plurality of curved surface portions arranged and connected in sequence around the central axis; at least two adjacent curved surface portions arranged around the central axis are mirror-symmetrical, so that after the outgoing light of the backlight source passes through the second surface and the first surface in sequence, the target illumination areas formed by each lens on the target plane are not separated.

2. The dimming element according to claim 1, wherein: The target illumination area is an axisymmetric figure having multiple axes of symmetry, and the target illumination area is divided into multiple sub-areas by the multiple axes of symmetry; Every two adjacent curved surface portions arranged around the central axis are mirror-symmetrical, and the sub-regions correspond to the curved surface portions one-to-one. The sub-regions are regions illuminated on the target plane by outgoing light from the corresponding curved surface portions.

3. The dimming element according to claim 2, wherein: The target illumination area is rectangular, and the first surface includes four curved surface portions; Alternatively, the target illumination area is a square, and the first surface includes eight curved surface portions; Alternatively, the target illumination area is hexagonal, and the first surface includes six curved surface portions.

4. The dimming element according to any one of claims 1 to 3, characterized in that: The curved surface is a free-form surface, and is obtained by combining a plurality of free-form curves in a predetermined arrangement; In which, the multiple free curves can be rotated to form multiple rotational symmetry planes, and the multiple circular illumination areas formed by the multiple rotational symmetry planes on the target plane are nested and concentric in sequence. The innermost one of the multiple circular illumination areas is the inscribed circular area of ​​the target illumination area, and the outermost one of the multiple circular illumination areas is the circumscribed circular area of ​​the target illumination area.

5. The dimming element according to any one of claims 1 to 3, characterized in that: The target illumination area includes a central sub-area and an edge sub-area surrounding the central sub-area, and the edge sub-areas corresponding to two adjacent lenses overlap.

6. The dimming element according to any one of claims 1 to 3, characterized in that: The multiple lenses are arranged in an array.

7. An image source in a head-up display device, characterized in that: include: a backlight source, the backlight source comprising a plurality of backlight light sources; The dimming element according to any one of claims 1 to 6, wherein each of the lenses in the dimming element is arranged on the light-emitting side of one of the backlight light sources; A display panel is provided on the light-emitting side of the target plane of the dimming element, and is used for converting the light emitted by the dimming element into image light and outputting the image light to a preset area.

8. The image source according to claim 7, characterized in that The display panel includes a plurality of pixels; The image source also includes a direction control element, which is arranged between the dimming element and the display panel and is used to adjust the direction of the light emitted by the dimming element so that the main optical axis of at least part of the pixel emitted light converges to a target sub-area in the preset area, and the target sub-area is smaller than the preset area.

9. The image source according to claim 8, characterized in that The direction control element includes a convex lens, a concave lens, a Fresnel lens or a combination of one or more thereof.

10. The image source according to claim 8, characterized in that The direction control element includes: a substrate, the substrate having a third surface and a fourth surface opposite to each other, the third surface being a curved surface, one of the third surface and the fourth surface facing the backlight source, and the other facing away from the backlight source; A Fresnel lens is located on the third surface and is integrally formed with the substrate.

11. The image source according to claim 10, characterized in that The third surface includes at least one of a convex surface, a concave surface, and a free-form surface; The surface shape of the Fresnel lens includes at least one of a convex surface, a concave surface and a free-form surface.

12. The image source according to any one of claims 8 to 11, characterized in that The image source also includes: a plurality of optical microstructures, which are located on a side of the direction control element close to or away from the backlight source, and include: at least one focusing structure for converging the received light, and / or, at least one diverging structure for diverging the received light.

13. The image source according to claim 12, characterized in that The optical microstructure and the direction control element are integrally formed. When the direction control element comprises a substrate and a Fresnel lens disposed on a third surface of the substrate, the optical microstructure is located on a side of the substrate away from the Fresnel lens.

14. The image source according to claim 12, wherein: The optical microstructure is a cylindrical lens structure, and a plurality of the optical microstructures are arranged side by side in a first direction.

15. The image source according to claim 14, characterized in that When the plurality of optical microstructures include a plurality of light-concentrating structures and a plurality of light-diverging structures, the light-concentrating structures and the light-diverging structures are alternately arranged in the first direction.

16. The image source according to claim 12, wherein: The optical microstructure is a spherical lens structure, and a plurality of the optical microstructures are arranged in an array.

17. The image source according to claim 16, characterized in that When the plurality of optical microstructures include a plurality of light-concentrating structures and a plurality of light-diverging structures, the light-concentrating structures and the light-diverging structures are alternately arranged in both the row direction and the column direction.

18. A head-up display device, characterized in that: include: The image source according to any one of claims 7 to 17; An output element is configured to receive the image light and output the image light to the preset area.

19. A vehicle, characterized in that: include: The head-up display device according to claim 18; A reflective imaging element is used to reflect the image light emitted by the head-up display device to the preset area.

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