Patent Publication Number: US-2022214542-A1

Title: Light control apparatus, passive light-emitting image source and head-up display system

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present patent application claims priority of Chinese Patent Application No. 202010295102.6 filed on Apr. 15, 2020 and priority of Chinese Patent Application No. 201910412218.0 filed on May 17, 2019, the disclosure of which is incorporated herein by reference in its entirety as part of the present application. 
     TECHNICAL FIELD 
     Embodiments of the present disclosure relate to a light control apparatus, a passive light-emitting image source and a head-up display system. 
     BACKGROUND 
     The head-up display (HUD) technology adopts an optical reflection principle to project vehicle information such as vehicle speed on a windshield or other glass, which may avoid distraction caused by a driver looking down at a dashboard during driving, thereby bringing a better driving experience while improving a driving safety factor. 
     A common windshield HUD image source is mostly a liquid crystal display (LCD). If the HUD adopts a traditional LCD image source, brightness of an HUD image displayed through the windshield is low; and generally, brightness of the LCD image source needs to be increased to ensure the brightness of the HUD image displayed through the windshield, which not only leads to higher power consumption of the image source, but also causes greater heat generation, increasing heat dissipation requirements for HUD. When a large-sized image needs to be formed through the windshield, the power consumption of the image source in HUD will further increase. 
     A light source refers to an object that can emit electromagnetic waves in a certain wavelength range (e.g., visible light, ultraviolet, or infrared, etc.); for example, the object is a light emitting diode (LED). In a field of lighting and display imaging, the light source is an indispensable device. 
     Usually, a device containing a light source (e.g., a lighting device, or a liquid crystal display, etc.) simply uses light emitted by the light source; and the light source is usually a point light source or an approximate point light source, that is, the light source emits light around, and a usual light source device has a low utilization rate of the light source. 
     For example, when some display imaging devices (e.g., liquid crystal displays) use a backlight source for imaging, only a small portion of light emitted by the backlight source is used for imaging, resulting in low imaging brightness. Although the problem of low imaging brightness may be solved by increasing power of the light source, this will correspondingly bring about problems of high power consumption and great heat generation of the light source, thereby increasing heat dissipation requirements for the light source device. 
     SUMMARY 
     Embodiments of the present disclosure provide a light control apparatus, a passive light-emitting image source and a head-up display system. 
     Embodiments of the present disclosure provide a head-up display system, which includes: a light source, a collimator element, a light concentrator element, a diffuser element, a liquid crystal panel and a transflective reflection device for displaying; the light concentrator element, the diffuser element and the liquid crystal panel are on a same side of the light source in an overlapped manner; the collimator element is configured to adjust light emitted by the light source to exit in a direction at an angle within a preset angle range; the light concentrator element is configured to concentrate the light emitted by the light source; the diffuser element is configured to diffuse the light emitted by the light source; the liquid crystal panel is configured to convert the light emitted by the light source into imaging light, and allow the imaging light to be incident on the reflection device for displaying; and the reflection device for displaying is configured to reflect the imaging light to a preset region. 
     In some examples, the light emitted by the light source reaches the preset region after reaching the collimator element, the light concentrator element, the diffuser element, the liquid crystal panel and the reflection device for displaying; the light concentrator element is configured to concentrate the light emitted by the light source and light concentrated by the light concentrator element reaches a preset position in the preset region on the assumption that the diffuser element is removed from an optical path from the light source to the preset region, and an area of the preset position is smaller than an area of the preset region. 
     In some examples, the collimator element is partially or entirely arranged between the light source and the light concentrator element; and the collimator element is configured to emit adjusted light to the light concentrator element. 
     In some examples, the collimator element is configured to adjust the light emitted by the light source into parallel light. 
     In some examples, the collimator element is between the light source and the light concentrator element, and the collimator element includes at least one selected from the group consisting of a collimating lens and a collimating film; the collimating lens includes one or more selected from the group consisting of a convex lens, a Fresnel lens, and a combination of lenses. 
     In some examples, the collimator element includes the collimating lens, and a distance between the collimating lens and a position of the light source is equal to a focal length of the collimating lens. 
     In some examples, the collimator element includes a hollow lamp cup; the hollow lamp cup includes a hollow housing provided with an inner reflective surface, a port of the hollow lamp cup faces the light concentrator element, the light source is at an end portion of the hollow lamp cup and the end portion is away from the port. 
     In some examples, the collimator element is inside the hollow lamp cup, and a size of the collimator element is smaller than a size of the port of the hollow lamp cup; the collimator element is configured to collimate a portion of the light emitted by the light source in the hollow lamp cup and then emit the portion of the light to the light concentrator element; and the collimator element includes at least one selected from the group consisting of a collimating lens and a collimating film. 
     In some examples, the collimator element includes a lamp cup with a solid center; the lamp cup with a solid center is a transparent component with a solid center, and a refractive index of the transparent component with the solid center is larger than 1; a port of the lamp cup with a solid center faces the light concentrator element; the light source is at an end portion of the lamp cup with the solid center, the end portion is away from the port; and the light emitted by the light source is totally reflected when the light is incident on an inner surface of the transparent component with the solid center. 
     In some examples, a cavity is at the end portion of the lamp cup with a solid center away from the port of the lamp cup with the solid center, and a surface, close to the port of the lamp cup with the solid center, of the cavity is a convex surface; or a slot is in a central position, close to an end portion with the port of the lamp cup with the solid center, of the lamp cup with the solid center, and a bottom surface of the slot is a convex surface. 
     In some examples, the light concentrator element is between the collimator element and the diffuser element; and the light concentrator element is configured to emit concentrated light to the diffuser element. 
     In some examples, the light concentrator element includes one or more selected from the group consisting of a convex lens, a Fresnel lens, and a combination of lenses. 
     In some examples, a distance between the light concentrator element and a mirror position is a focal length of the light concentrator element; and the mirror position is a position of a virtual image formed by the preset position through the reflection device for displaying. 
     In some examples, the diffuser element includes a first diffuser element, and the first diffuser element is between the light source and the liquid crystal panel; the first diffuser element is configured to diffuse light concentrated by the light concentrator element. 
     In some examples, the diffuser element further includes a second diffuser element, and the first diffuser element and the second diffuser element are overlapped, and a preset distance is between the first diffuser element and the second diffuser element. 
     In some examples, the first diffuser element and the second diffuser element are respectively arranged on two sides of the light concentrator element; or, the first diffuser element and the second diffuser element are both arranged on a side, close to the liquid crystal panel, of the light concentrator element. 
     In some examples, the preset distance is in a range of 40 mm to 50 mm. 
     In some examples, the diffuser element includes a diffractive optical element or a scattering optical element. 
     In some examples, the diffractive optical element is configured such that light passing through the diffractive optical element is diffused by the diffractive optical element to form one or more observation ranges with a preset cross-sectional shape, and the preset cross-sectional shape includes a circle, an ellipse, a square, or a rectangle. 
     In some examples, the head-up display system further includes a polarization controller element, wherein the liquid crystal panel includes a first polarizer, a liquid crystal layer, and a second polarizer; the first polarizer and the second polarizer are respectively arranged on two sides of the liquid crystal layer; the first polarizer is between the liquid crystal layer and the light source; the first polarizer is configured to transmit first linearly polarized light; the second polarizer is configured to transmit second linearly polarized light, and a polarization direction of the second linearly polarized light is perpendicular to a polarization direction of the first linearly polarized light; the polarization controller element is between the light source and the first polarizer, and the polarization controller element is configured to transmit the first linearly polarized light and reflect or absorb the second linearly polarized light. 
     In some examples, the head-up display system further includes: a light blocking layer, the light blocking layer is on a side, away from the light source, of the liquid crystal panel, and the light blocking layer is configured to restrict an exit angle of exit light from the liquid crystal panel. 
     In some examples, the head-up display system further includes: a barrier layer, wherein the barrier layer is on a side of the liquid crystal panel, the side is away from the light source, a preset distance is between the barrier layer and the liquid crystal panel, and a barrier unit includes a liquid crystal, or the barrier layer includes an integral-type liquid crystal, and a plurality of barrier units arranged at intervals are formed by controlling a working state of a liquid crystal unit of the integral-type liquid crystal. 
     In some examples, the head-up display system further includes a light scattering layer, the light scattering layer is on a side, away from the liquid crystal panel, of the light blocking layer, and the light scattering layer is configured to scatter external ambient light. 
     In some examples, the head-up display system includes a plurality of light sources; the plurality of light sources are in different positions; and the light concentrator element is configured to concentrate light emitted by the plurality of light sources in the different positions. 
     In some examples, a count of collimator elements is plural, and different collimator elements are in different positions, and are configured to adjust exit directions of the light emitted by the plurality of light sources in the different positions, so that the exit directions of the light emitted by the plurality of light sources in the different positions all point to a same preset position. 
     In some examples, the light source is an electroluminescent array including one or more electroluminescent modules, and each of the electroluminescent modules includes one or more electroluminescent devices; and each of the electroluminescent modules is correspondingly provided with at least one hollow lamp cup. 
     In some examples, the light source includes a plurality of light sources groups; and light emitted by different light source groups is emitted to different directions or regions. 
     In some examples, the liquid crystal panel includes red, green and blue filters; or the liquid crystal panel includes a liquid crystal layer, the liquid crystal layer is a blue phase liquid crystal, and the light source includes a red light source, a green light source, and a blue light source; the red light source, the green light source, and the blue light source are configured to operate periodically, and not to operate at same time. 
     In some examples, the head-up display system further includes a liquid crystal converting layer, wherein the liquid crystal panel includes a liquid crystal layer; and the liquid crystal converting layer is on a side, away from the light source, of the light concentrator element; the liquid crystal converting layer includes a plurality of liquid crystal units arranged at intervals; and one liquid crystal unit in the liquid crystal converting layer corresponds to one liquid crystal unit in the liquid crystal layer; the liquid crystal units in the liquid crystal layer are configured to convert light in a first polarization direction into light in a second polarization direction; the liquid crystal units in the liquid crystal converting layer are configured to convert light in the second polarization direction into light in the first polarization direction; and the first polarization direction is perpendicular to the second polarization direction. 
     In some examples, a total area of all liquid crystal units in the liquid crystal converting layer is not less than half of a total area of all liquid crystal units in the liquid crystal layer. 
     In some examples, the head-up display system further includes: a cylindrical lens layer, wherein the cylindrical lens layer is on a side, away from the light source, of the liquid crystal layer; the cylindrical lens layer includes a plurality of vertically arranged cylindrical lenses, each cylindrical lens covers at least two different columns of liquid crystal units in the liquid crystal layer; the cylindrical lens is configured to emit light emitted from one column of liquid crystal units to a first position, and emit light emitted from the other column of liquid crystal units to a second position. 
     Embodiments of the present disclosure further provide a light control apparatus, which includes: a diffuser element and a direction controller element; the direction controller element is configured to concentrate light emitted by a plurality of light sources located in different positions; and the diffuser element is on a side, away from the plurality of light sources, of the direction controller element; and the diffuser element is configured such that light emitted by the direction controller element is diffused by the diffuser element and form a light spot. 
     In some examples, the light emitted by the plurality of light sources passes through the direction controller element and the diffuser element to reach a first preset region; the light concentrator element is configured to concentrate the light emitted by the plurality of light sources, and light concentrated by the light concentrator element reaches a second preset region in the first preset region on the assumption that the diffuser element is removed from an optical path from plurality of light sources to the first preset region, and an area of the second preset region is smaller than an area of the first preset region. 
     Embodiments of the present disclosure further provide a passive light-emitting image source, which includes a light source, a liquid crystal panel, and any one of the above light control apparatuses; the light source and the liquid crystal panel are respectively arranged on two sides of the direction controller element of the light control apparatus. 
     Embodiments of the present disclosure further provide a head-up display system, which includes any one of the above passive light-emitting image sources. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In order to illustrate the embodiments of the present disclosure or the technical solutions in the prior art more clearly, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present disclosure. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative effort. 
         FIG. 1  shows a first structural schematic diagram of a head-up display system provided by an embodiment of the present disclosure; 
         FIG. 2  shows a schematic diagram of an imaging principle of a head-up display system provided by an embodiment of the present disclosure; 
         FIG. 3 a    shows a schematic diagram of a principle of a diffuser element in a head-up display system provided by an embodiment of the present disclosure; 
         FIG. 3 b    shows a schematic diagram of another diffuser element in a head-up display system provided by an embodiment of the present disclosure; 
         FIG. 4  shows an imaging schematic diagram of a reflection device for displaying in a head-up display system provided by an embodiment of the present disclosure; 
         FIG. 5  shows a second structural schematic diagram of a head-up display system provided by an embodiment of the present disclosure; 
         FIG. 6  shows a third structural schematic diagram of a head-up display system provided by an embodiment of the present disclosure; 
         FIG. 7 a    shows a first arrangement schematic diagram of collimator elements provided by an embodiment of the present disclosure; 
         FIG. 7 b    shows a second arrangement schematic diagram of collimator elements provided by an embodiment of the present disclosure; 
         FIG. 8 a    shows a third arrangement schematic diagram of collimator elements provided by an embodiment of the present disclosure; 
         FIG. 8 b    shows a fourth arrangement schematic diagram of collimator elements provided by an embodiment of the present disclosure; 
         FIG. 9  shows a fifth arrangement schematic diagram of collimator elements provided by an embodiment of the present disclosure; 
         FIG. 10 a    shows a sixth arrangement schematic diagram of collimator elements provided by an embodiment of the present disclosure; 
         FIG. 10 b    shows a seventh arrangement schematic diagram of collimator elements provided by an embodiment of the present disclosure; 
         FIG. 11  shows a first structural schematic diagram of an image source in a head-up display system provided by an embodiment of the present disclosure; 
         FIG. 12  shows a second structural schematic diagram of an image source in a head-up display system provided by an embodiment of the present disclosure; 
         FIG. 13  shows a third structural schematic diagram of an image source in a head-up display system provided by an embodiment of the present disclosure; 
         FIG. 14  shows a structural schematic diagram of a lamp cup in a head-up display system provided by an embodiment of the present disclosure; 
         FIG. 15 a    shows a schematic diagram of light propagation of a quadrangular pyramid collimator element in a head-up display system provided by an embodiment of the present disclosure; 
         FIG. 15 b    shows an arrangement schematic diagram of light sources in a quadrangular pyramid collimator element in a head-up display system provided by an embodiment of the present disclosure; 
         FIG. 15 c    shows another arrangement schematic diagram of light sources in a quadrangular pyramid collimator element in a head-up display system provided by an embodiment of the present disclosure; 
         FIG. 15 d    shows further another arrangement schematic diagram of light sources in a quadrangular pyramid collimator element in a head-up display system provided by an embodiment of the present disclosure; 
         FIG. 16  shows a structural schematic diagram of a roof-shaped lamp cup in a head-up display system provided by an embodiment of the present disclosure; 
         FIG. 17  shows a first structural schematic diagram of a lamp cup with a solid center in a head-up display system provided by an embodiment of the present disclosure; 
         FIG. 18  shows a second structural schematic diagram of a lamp cup with a solid center in a head-up display system provided by an embodiment of the present disclosure; 
         FIG. 19  shows a fourth structural schematic diagram of an image source in a head-up display system provided by an embodiment of the present disclosure; 
         FIG. 20  shows a fifth structural schematic diagram of an image source in a head-up display system provided by an embodiment of the present disclosure; 
         FIG. 21  shows a sixth structural schematic diagram of an image source in a head-up display system provided by an embodiment of the present disclosure; 
         FIG. 22  shows a first structural schematic diagram of a light control apparatus provided by an embodiment of the present disclosure; 
         FIG. 23  shows a second structural schematic diagram of a light control apparatus provided by an embodiment of the present disclosure; 
         FIG. 24  shows a schematic diagram of a light control apparatus provided by an embodiment of the present disclosure when imaging on a windshield; 
         FIG. 25  shows a first structural schematic diagram of a passive light-emitting image source provided by an embodiment of the present disclosure; 
         FIG. 26  shows a second structural schematic diagram of a passive light-emitting image source provided by an embodiment of the present disclosure; 
         FIG. 27 a    shows a first arrangement schematic diagram of an electroluminescent array provided by an embodiment of the present disclosure; 
         FIG. 27 b    shows a second arrangement schematic diagram of an electroluminescent array provided by an embodiment of the present disclosure; 
         FIG. 27 c    shows a third arrangement schematic diagram of an electroluminescent array provided by an embodiment of the present disclosure; 
         FIG. 27 d    shows a fourth arrangement schematic diagram of an electroluminescent array provided by an embodiment of the present disclosure; 
         FIG. 28  shows a third structural schematic diagram of a passive light-emitting image source provided by an embodiment of the present disclosure; 
         FIG. 29  shows a first schematic diagram of an observer viewing imaging of a passive light-emitting image source provided by an embodiment of the present disclosure; 
         FIG. 30  shows a second schematic diagram of an observer viewing imaging of a passive light-emitting image source provided by an embodiment of the present disclosure; 
         FIG. 31  shows a fourth structural schematic diagram of a passive light-emitting image source provided by an embodiment of the present disclosure; 
         FIG. 32 a    shows a first schematic diagram of an observer viewing imaging of a passive light-emitting image source provided by an embodiment of the present disclosure; 
         FIG. 32 b    shows a second schematic diagram of an observer viewing imaging of a passive light-emitting image source provided by an embodiment of the present disclosure; 
         FIG. 33  shows a first structural schematic diagram of a 3D passive light-emitting image source provided by an embodiment of the present disclosure; 
         FIG. 34  shows a second structural schematic diagram of a 3D passive light-emitting image source provided by an embodiment of the present disclosure; 
         FIG. 35  shows a third structural schematic diagram of a 3D passive light-emitting image source provided by an embodiment of the present disclosure; and 
         FIG. 36  shows a fourth structural schematic diagram of a 3D passive light-emitting image source provided by an embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     In the description of the present disclosure, it should be understood that directional or positional relationships shown by terms such as “center”, “longitudinal”, “transverse”, “length”, “width”, “thickness”, “upper”, “lower”, “front”, “rear”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inner”, “outer”, “clockwise” and “counterclockwise” are directional or positional relationships shown as in the drawings, which only means to facilitate description of the present disclosure and simplify the description, but do not indicate or imply that the apparatuses or components must have specific directions, or be constructed or operated in the specific directions, and are not limitative of the present disclosure. 
     In addition, terms like “first” and “second” are merely used for the purpose of description other than indicating or implying their relative importance or implicitly denoting the number of technical features indicated thereby. Thus, features with “first” or “second” defined may include one or more of the features either explicitly or implicitly. In the description of the present disclosure, the term “a plurality of” refers to two or more, unless otherwise specified. 
     In the description of the embodiments of the present disclosure, unless otherwise unambiguously specified and defined, terms like “mounting”, “coupling”, “connecting” and “fixing” should be construed in broad sense, for example, it may be fixed connection, or detachable connection, or integral connection; or may also be mechanical connection or electrical connection; or may also be direct connection, or indirect connection through an intermediate medium; or may also be internal communication between two components. It will be understood by those ordinarily skilled in the art that the specific meanings of the above terms in the embodiments of the present disclosure can be understood according to specific circumstances. 
     An embodiment of the present disclosure provides a head-up display system, which controls an exit angle of light by concentrating and diffusing the light, thereby improving imaging brightness of the head-up display system. Referring to  FIG. 1 , the head-up display system includes: a light source  10 , a collimator element  20 , a direction controller element  30 , a first diffuser element  41 , a liquid crystal panel  50 , and a transflective reflection device for displaying  60 . As shown in  FIG. 1 , the direction controller element  30 , the first diffuser element  41  and the liquid crystal panel  50  are arranged on a same side of the light source  10  in a stacked manner. 
     In an embodiment of the present disclosure, the light source  10  may emit light; and the collimator element  20  is configured to adjust an exit direction of the light emitted by the light source  10  to be at an angle within a preset angle range, to collimate the light emitted by the light source  10 . The direction controller element  30  is configured to concentrate the light emitted by the light source  10 ; and the first diffuser element  41  is configured to diffuse the light emitted by the light source  10 . The liquid crystal panel  50  is configured to convert the light emitted by the light source  10  into imaging light, and allow the imaging light to be incident to the reflection device for displaying  60 ; and the reflection device for displaying  60  is configured to reflect the imaging light to a preset region  200 , so that an observer (e.g., a driver, or a passenger, etc.) may view the image formed by the liquid crystal panel  50 , when his/her eyes are located in the preset region  200 . That is, the light emitted by the light source reaches the preset region after reaching the collimator element, a light concentrator element, the first diffuser element, the liquid crystal panel and the reflection device for displaying to. According to this embodiment, the imaging light is light emitted by the liquid crystal panel  50 ; the imaging light essentially comes from the light emitted by the light source  10 ; each pixel of the liquid crystal panel  50  may be controlled as to whether to transmit the light emitted by the light source  10 , so that the observer may view the image formed by the liquid crystal panel  50  when seeing the light passing through the liquid crystal panel  50  (i.e., the imaging light); and the content of the image formed by the liquid crystal panel  50  is the content of the HUD image that can be viewed by the observer. 
     In an embodiment of the present disclosure, since the light source  10  is generally a point light source, that is, the light emitted by the light source  10  is emitted at various angles; according to this embodiment, the exit direction of the light emitted by the light source  10  may be adjusted into the preset angle range through the collimator element  20 , so as to collimate a light propagation direction. 
     Assuming that the first diffuser element  41  is removed from an optical path from the light source to the preset region, the light directly or indirectly emitted by the light source  10  may be concentrated by the direction controller element  30  and then reaches a preset position  100 . The preset position  100  is located within the preset region; and an area of the preset position is smaller than an area of the preset region. For example, the light directly emitted by the light source  10  refers to: the light which is emitted by the light source  10  and is directly incident to the direction controller element  30 ; and the light indirectly emitted by the light source  10  refers to: the light which is emitted by the light source and is incident to the direction controller element  30  after reaching other component (e.g., the collimator element  20 , or the first diffuser element  41 , etc.). In this embodiment, by providing the direction controller element  30 , the light may be concentrated to the preset position  100 ; the concentrated light is used as backlight for the liquid crystal panel  50 , so that the light may be used for imaging, and further the observer whose eye is at the preset position  100  where the light is converged can observe a complete image; because the light is concentrated, the imaging brightness is higher, and the observer may view an image with higher brightness. Optionally, the collimator element  20  is configured to adjust the light emitted by the light source  10  to parallel light or approximately parallel light, so as to facilitate the direction controller element  30  to uniformly adjust the exit direction of the collimated parallel light. Optionally, the direction controller element  30  includes one or more selected from the group consisting of a convex lens, a concave lens, a Fresnel lens, or a combination thereof. That is, for example, the direction controller element  30  is, illustratively, a Fresnel lens, or may also be a convex lens, or may also be a combination of lenses (e.g., a combination of a convex lens and a concave lens, or a combination of a Fresnel lens and a convex lens, etc.). 
     Also, in order to expand an imaging range to increase the region for the observer to view the image, in an embodiment of the present disclosure, the light emitted by the light source  10  is diffused based on the first diffuser element  41 , so that the light after diffusion may reach a preset observation range (the preset region)  200 . For example, the first diffuser element  41  may diffuse the light directly or indirectly emitted by the light source  10 ; in this case, the light directly emitted by the light source  10  refers to: the light emitted by the light source  10  and directly incident to the first diffuser element  41 , and the light indirectly emitted by the light source  10  refers to: the light emitted by the light source and incident to the first diffuser element  41  after reaching other component (e.g., the collimator element  20 , or the direction controller element  30 , etc.). 
     In this embodiment, the light emitted by the light source  10  is concentrated and diffused by the direction controller element  30  and the first diffuser element  41 , and the concentrated and diffused light serves as the backlight for the liquid crystal panel  50 , so that the liquid crystal panel  50  can image normally, and the imaging light during imaging is reflected by the reflection device for displaying  60  and then reaches the preset position  100 , so that the observer whose eye is located at the preset position  100  may view the image formed by the liquid crystal panel  50 , and in this case, the image viewed by the observer is a virtual image  300  formed by the reflection device for displaying  60  by means of reflection imaging; and, under an action of the first diffuser element  41 , for example, the imaging light is diffused and then reaches the observation range  200 , so that the observer may view the image formed by the liquid crystal panel  50  when the eyes are located at any position within the observation range  200 . For example, the preset position  100  is a position within the observation range  200 . For example, the observer may be a driver or a passenger; in this case, a region where the observer needs to view the imaging, that is, an eyebox region, may be preset according to actual needs; and the eyebox region refers to a region where the observer&#39;s eyes are located and can see the HUD image. In this case, it is only necessary that the above-described observation range  200  may cover the eyebox region, and for example, a center of the eyebox region is set as the preset position  100 . In this embodiment, the eyebox region has a certain size; even if the observer&#39;s eyes deviate from the center of the eyebox region by a certain distance, for example, move up and down, left and right by a certain distance, the observer will still see the HUD image as long as the observer&#39;s eyes are still located within the eyebox region. 
     For example, for a working principle of the head-up display system,  FIG. 2  may be referred to; for convenience of description, in  FIG. 2 , the reflection device for displaying  60  being planar is taken as an example to illustrate. As shown in  FIG. 2 , the collimator element  20  collimates the light emitted by the light source  10 ; it is illustrated in  FIG. 2  by taking the collimated light as parallel light, and the parallel light may be adjusted to the light required for imaging after passing through the direction controller element  30  and the first diffuser element  41 . It is illustrated in  FIG. 2  by taking leftmost light A′ as an example, the light A′ is adjusted to light A toward the preset position  100  after passing through the direction controller element  30 , and due to the presence of the reflection device for displaying  60 , the light A is actually toward a mirror position  101  of the preset position  100 ; if there is no first diffuser element  41 , the light A may travel toward the preset position  100  along the optical path a after being reflected by the reflection device for displaying  60 ; in a case that the first diffuser element  41  exists, the first diffuser element  41  diffuses the light A into light with a plurality of exit angles (e.g., light A 1 , light A 2 , etc. in  FIG. 2 ); diffused light may be spread into a range, that is, the observation range  200 , after being reflected by the reflection device for displaying  60 , so that when the observer&#39;s eye is within the observation range  200 , the observer can always view the image formed by the liquid crystal panel  50 . Similarly, the diffused light A 1 , light A 2 , etc. are directly toward the mirror range  201  of the observation range  200 . In addition, in practical applications, for example, the reflection device for displaying  60  has a certain curvature, an imaging principle thereof is similar to that shown in  FIG. 2 , and no details will be repeated here. Those skilled in the art can understand that, for example, a curved reflection device for displaying  60  is a windshield, when viewed in different positions, a position of the virtual image  300  is not fixed; so when the reflection device for displaying  60  is a curved windshield or imaging window, the virtual image  300  in this embodiment refers to the virtual image  300  that may be seen when observed from the preset position  100 , that is, the position of the virtual image  300  is the position of the virtual image when the observer observes from the preset position  100 . 
     For example, the first diffuser element  41  may be a low-cost scattering optical element, for example, a homogenizer, or a diffuser, etc. Or, for example, the first diffuser element  41  is a diffractive optical element (DOE) with better control of the diffusion effect, for example, a beam shaper, etc. For example, light is scattered when passing through the scattering optical element, for example, the homogenizer; the light after passing through the scattering optical element is in many different angles, and a small amount of diffraction also occurs; and, scattering of light plays a major role and a formed spot is relatively large. The diffractive optical element has certain microstructures designed at a surface thereof, and plays a role in light beam expansion mainly through diffraction, leading to a smaller light spot, a size and a shape of the light spot being controllable. 
     In this embodiment, after passing through the first diffuser element  41 , the light is transformed into a light beam, whose cross section in a direction perpendicular to the propagation direction of main chief light has a specific shape, that is, the first diffuser element  41  may diffract light passing through it and the light diffracted by the first diffuser element  41  forms the observation range  200  with a certain shape; and a size and a shape of the observation range  200  formed by diffraction are mainly determined by the microstructures of the first diffuser element  41 . Optionally, the shape of the observation range  200  includes, but is not limited to, a circle, an ellipse, a square, or a rectangle. As shown in  FIG. 3 a   , after the light passes through the first diffuser element  41  which is illustratively a diffractive optical element, the light is diffused and forms a certain cross-sectional shape; the cross-sectional shape corresponds to the shape of the observation range  200 ;  FIG. 3 a    takes the observation range  200  being a rectangle as an example to illustrate; and the above-described  FIG. 2  also takes the observation range  200  being a rectangle as an example to illustrate. 
     Further, for example, the first diffuser element  41  is a diffuser element of a discrete type, that is, for example, the first diffuser element  41  diffuses the light passing through it to a plurality of ranges; and a shape of each range includes, but is not limited to, a circle, an ellipse, a square, or a rectangle. As shown in  FIG. 3 b   , after passing through the first diffuser element  41  of the discrete type, for example, the light is diffused to a plurality of regions, each region corresponds to an observation range  200 ; and in  FIG. 3 b   , it is illustrated by taking that the light is diffused to two rectangular regions as an example.  FIG. 3 b    shows light L 1  incident to the first diffuser element  41  and light L 2  after being diffused by the first diffuser element  41 . 
     In addition, optionally, in order to better achieve a concentration effect, the preset position  100  corresponds to a focal point of the direction controller element  30 . In this embodiment, a distance between the direction controller element  30  and the mirror position  101  is a focal length of the direction controller element  30 . For example, the mirror position  101  is a position of the virtual image formed by the preset position  100  through the reflection device for displaying  60 , for which  FIG. 4  may be specifically referred to. 
     In an embodiment of the present disclosure, except the reflection device for displaying  60 , the light source  10 , the collimator element  20 , the direction controller element  30 , the first diffuser element  41  and the liquid crystal panel  50 , etc. for example form an image source 1 of the head-up display system, that is, the image source 1 includes the light source  10 , the collimator element  20 , the direction controller element  30 , the first diffuser element  41  and the liquid crystal panel  50 , etc. As shown in  FIG. 4 , the imaging light emitted by the image source 1 (i.e., the imaging light emitted by the liquid crystal panel  50 ) is reflected by the reflection device for displaying  60  and then reaches the preset position  100 , so that the observer whose eyes are located at the preset position  100  can view the virtual image  300  formed by the reflection device for displaying  60 ; meanwhile, with respect to an object in the preset position  100 , a virtual image of the object may also be formed on the other side of the reflection device for displaying  60 , and a position of the virtual image of the object is just the mirror position  101 . And, because the reflection device for displaying  60  is not necessarily planar, the “distance between the direction controller element  30  and the mirror position  101 ” in this embodiment specifically refers to an optical path distance when the light is incident from the direction controller element  30  to the mirror position  101 . 
     For example, the head-up display system is installed on a transportation means such as a vehicle; for example, the reflection device for displaying  60  in the embodiment is a windshield of the vehicle or a film attached to the windshield; and the reflection device for displaying  60  has a transflective characteristic, which allows the imaging light emitted by the liquid crystal panel  50  to be reflected by the reflection device for displaying  60  to the preset position  100 ; meanwhile, the light from outside the vehicle may also pass through the reflection device for displaying  60  and reach the preset position  100 , so that the observer in the preset position  100  can also view a scene outside the vehicle normally. For example, the “transflective characteristic” in this embodiment refers to that the reflection device for displaying  60  can transmit light and can also reflect light, and it is not limited to transmit 50% of the light and reflect 50% of the light. 
     Optionally, when the head-up display system is installed on a transportation means such as a vehicle, for example, the first diffuser element  41  of the discrete type is adopted, that is, for example, the first diffuser element  41  diffuse the light emitted by the light source  10  to a plurality of observation ranges  200 . For example, the first diffuser element  41  diffuses the light emitted by the light source  10  to two observation ranges  200 , and the two observation ranges  200  respectively correspond to a driver and a co-pilot passenger, so that both the driver and the co-pilot passenger may view the image formed by the liquid crystal panel  50 , which can minimize light loss and improve the light utilization rate. 
     In the head-up display system provided by the embodiment of the present disclosure, the direction controller element  30  and the first diffuser element  41  respectively concentrate and diffuse light, so that the light emitted by the light source  10  can be effectively restricted in the observation range  200 , and the observer can normally view the image formed by the liquid crystal panel  50  through the reflection of the reflection device for displaying  60  in the observation range  200 ; most or all of the light from the light source  10  may be converged in the observation range  200  by means of concentrating and diffusing, which can improve brightness during imaging, and improve the light utilization rate, so that the light source  10  can ensure imaging brightness even at a lower power, so as to reduce power consumption of the head-up display system, and reduce heat generation. Even if a large-area liquid crystal panel  50  needs to be provided for large-sized imaging, in this case, the increased power consumption is small, that is, the head-up display system is also suitable for large-area imaging Also, collimating the light emitted by the light source  10  based on the collimator element  20  facilitates the direction controller element  30  and the first diffuser element  41  to more effectively concentrate and diffuse the light, and facilitates control of light. 
     On the basis of the above-described embodiments, the direction controller element  30 , the first diffuser element  41 , and the liquid crystal panel  50  may be arranged in a variety of stacked manners. As shown in  FIG. 1 , the direction controller element  30 , the first diffuser element  41 , and the liquid crystal panel  50  are sequentially stacked along the exit direction of the light of the light source  10 , that is, the light from the light source  10  is firstly concentrated and then diffused, and then used as backlight for imaging. Or, as shown in  FIG. 5 , the first diffuser element  41 , the direction controller element  30 , and the liquid crystal panel  50  are sequentially stacked along the exit direction of the light from the light source  10 , that is, the light from the light source  10  is firstly diffused and then concentrated, and then used as backlight for imaging. Or, as shown in  FIG. 6 , the direction controller element  30 , the liquid crystal panel  50 , and the first diffuser element  41  are sequentially stacked along the exit direction of the light from the light source  10 , that is, the light from the light source  10  is firstly concentrated, then directly used as backlight for imaging, and finally the imaging light is diffused. Other stacked manners may be used, and no details will be repeated here. 
     For example, in order to control light more conveniently, in general, for example, the mode of concentrating firstly and then diffusing is adopted, that is, the light source  10  and the first diffuser element  41  are respectively arranged on two sides of the direction controller element  30 , and the first diffuser element  41  is configured to diffuse the light concentrated by the direction controller element  30 ; for the specific structure,  FIG. 1  or  FIG. 6  may be referred to. In addition, in order to reduce influence on imaging of the liquid crystal panel  50 , the first diffuser element  41  is arranged between the light source  10  and the liquid crystal panel  50 , as shown in  FIG. 1 . Also, for example, the light is collimated by the collimator element  20  firstly, and then concentrated and diffused, that is, the direction controller element  30  and the first diffuser element  41  are arranged on the same side of the collimator element  20 . In this embodiment, the direction controller element  30  is arranged between the collimator element  20  and the first diffuser element  41 ; and the direction controller element  30  is configured to concentrate the collimated light and emit the concentrated light to the first diffuser element  41 . 
     On the basis of the above-described embodiments, for example, the head-up display system is provided with a plurality of collimator elements  20 ; and each collimator element  20  is provided therein with one or more light sources  10 . For example, a plurality of light sources  10  may be arranged in a matrix into a light source point array, for example, 4 light sources  10  may be arranged in a 2×2 point array; or, a plurality of light sources  10  may also be arranged in a linear array, for example, 4 light sources  10  may be arranged in a 1×4 array. The collimator element  20  can collimate the light emitted by the light source  10  in the collimator element  20 ; and, for example, the plurality of collimator elements  20  are arranged in a closely-packed manner to avoid a case where some regions cannot form backlight. For example, as shown in  FIG. 7 a    and  FIG. 7 b   , a shape of the collimator element  20  is circular, and a plurality of collimator elements  20  are arranged in a closely-packed manner. For example, the “shape of the collimator element” in this embodiment refers to an outer contour shape of a cross-section of the collimator element  20 .  FIG. 1  is a side view of the head-up display system; and  FIG. 7 a    and  FIG. 7 b    are schematic diagrams of arrangement of the collimator elements  20  along a top view direction. 
     Because the light source  10  is generally a point light source, the circular collimator element  20  can make most efficient use of the light emitted by the light source  10  and improve the light utilization rate. Also, when the circular collimator elements  20  are closely arranged, there is a gap between two collimator elements  20 , thereby reducing a space utilization rate. In order to balance the light utilization rate and the space utilization rate, for example, the collimator elements  20  are arranged in a completely closely-packed manner. The “completely closely-packed manner” in this embodiment refers to that there may be no gaps between collimator elements  20  after the collimator elements  20  being closely packed. For example, when the shape of the collimator element  20  is a quadrilateral (e.g., a rhombus, a rectangle, etc.) or a hexagon (preferably a regular hexagon), completely closely-packed arrangement is implemented. Referring to  FIG. 8 a    and  FIG. 8 b   , a shape of the collimator element  20  is rectangular, and a plurality of collimator elements  20  are arranged in a completely closely-packed manner.  FIG. 8 a    and  FIG. 8 b    show two completely closely-packed manners of the rectangular collimator elements  20 . Or, referring to  FIG. 9 , a shape of the collimator element  20  is a regular hexagon, and a plurality of collimator elements  20  are arranged in a completely closely-packed manner. 
     For example, the regular hexagonal arrangement improves the space utilization rate, it also slightly reduces the light utilization rate. Optionally, a shape of a collimator element  20  is an octagon (e.g., a regular octagon), and a plurality of collimator elements  20  are arranged in a completely closely-packed manner. Furthermore, because octagons cannot be completely closely packed, for example, small light sources are used to fill the gaps. For example, as shown in  FIG. 10 a    and  FIG. 10 b   , a sub-collimator element whose size matches the gap is additionally provided in the gap between the plurality of collimator elements  20 . For example, the sub-collimator element may be of any shape, and it is illustrated in the diagram by taking the sub-collimator element being also an octagon as an example. Because the octagon is closer to a circle than a hexagon, the light utilization rate is higher, and the space utilization rate is also higher than that of an array arranged in a circle. 
     As shown in  FIG. 10 a    and  FIG. 10 b   , a large octagon represents a collimator element  20   a , and a small octagon represents a sub-collimator element  20   b . As shown in  FIG. 10 a    and  FIG. 10 b   , in order to make better use of space, one sub-collimator element  20   b  is arranged within a gap formed by four collimator elements  20   a ; each two adjacent collimator elements  20   a  among the four collimator elements  20   a  are in contact with each other, and the sub-collimator element  20   b  located in the gap is in contact with the four collimator elements  20   a . For example, a light source is provided for each sub-collimator element  20   b , and a light source is provided for each collimator element  20   a . The collimator element  20   a  represented by the large octagon may be referred to as a first collimator element, and the sub-collimator element  20   b  represented by the small octagon may be referred to as a second collimator element. 
     On the basis of the above-described embodiments, for example, the collimator element  20  collimates the light emitted by the light source  10 , and it may not implement perfect collimation in actual situations, resulting in relatively weak brightness at an edge of the collimator element  20 . For example, when a plurality of collimator elements  20  are arranged in a closely-packed manner, a gap between collimator elements  20  is easily to form a dark light region. In this embodiment, a plurality of diffuser elements are arranged at intervals to uniform light brightness. As shown in  FIG. 11 , the head-up display system further includes a second diffuser element  42 ; the first diffuser element  41  and the second diffuser element  42  are stacked, and the first diffuser element  41  and the second diffuser element  42  are separated by a preset distance. 
     In an embodiment of the present disclosure, both the first diffuser element  41  and the second diffuser element  42  can diffuse the light emitted by the light source  10 ; and, the first diffuser element  41  and the second diffuser element  42  can uniform the light collimated by the collimator element  20 , so that the imaging brightness of the liquid crystal panel  50  is more uniform. For example, each of the first diffuser element  41  and the second diffuser element  42  is essentially a kind of diffuser element, and for example, the diffuser element is illustratively a diffractive optical element (DOE), for example, a beam shaper, etc.; a size and a shape of the observation range  200  formed by diffraction are determined by the microstructure of the beam shaper. Or, for example, the diffuser element is a scattering optical element such as a homogenizer, or a diffuser, etc. For a specific structure of the scattering optical element, related description of the above-described first diffuser element  41  may be referred to, and no details will be repeated here. 
     In this embodiment, the head-up display system uses a plurality of diffuser elements (including the first diffuser element  41  and the second diffuser element  42 ) arranged at intervals, which not only diffuses light, but also uniforms light brightness, to ensure uniform imaging brightness of the liquid crystal panel  50 . 
     Also, in order that a plurality of diffuser elements can all play a corresponding role, there is a preset distance between adjacent diffuser elements; and for example, the preset distance is illustratively 40 mm to 50 mm. In addition, for example, the plurality of diffuser elements in this embodiment are all arranged on the same side of the direction controller element  30 ; as shown in  FIG. 11 , the first diffuser element  41  and the second diffuser element  42  are both arranged on a side of the direction controller element  30  that is close to the liquid crystal panel  50 . Or, when a thickness of the direction controller element  30  is not greater than the preset distance, for example, the diffuser elements are dispersedly arranged on two sides of the direction controller element  30  to reduce an overall thickness of the image source  1 . As shown in  FIG. 12 , the first diffuser element  41  and the second diffuser element  42  are respectively arranged on two sides of the direction controller element  30 . 
     On the basis of the above-described embodiments, in order to improve concentrating and diffusing effects of the direction controller element  30  and the first diffuser element  41 , in this embodiment, the light emitted by the light source  10  is firstly collimated, that is, the light source  10  and the collimator element  20  are arranged on the same side of the direction controller element  30  (or the first diffuser element  41 ); and, the collimator element  20  is partially or entirely arranged between the light source  10  and the direction controller element  30 ; and the collimator element  20  is configured to emit adjusted light to the direction controller element  30 . 
     In this embodiment, for example, the collimator element  20  includes a collimating lens  21  and/or a collimating film; and the collimating lens  21  and/or the collimating film are/is arranged between the light source  10  and the direction controller element  30 . For example, the collimating lens  21  includes one or more of a convex lens, a concave lens, a Fresnel lens, or a combination thereof (e.g., a combination of a convex lens and a concave lens, or a combination of a Fresnel lens and a concave lens, etc.). For example, the collimating film is a brightness enhancement film (BEF), which is used to adjust an exit direction of light to a preset angle range, for example, to concentrate the light within an angle range of −35° to +35° from a normal of the collimating film. In addition, for example, the light source  10  is provided at a focal point of the collimating lens  21 , that is, a distance between the collimating lens  21  and a position of the light source  10  is equal to a focal length of the collimating lens  21 , so that light of different directions from the light source  10  can be emitted in parallel after passing through the collimating lens  21 , as shown in  FIG. 13 . 
     In this embodiment, if the collimator element  20  only includes the collimating lens  21  and/or the collimating film, for example, the collimator element  20  is entirely located between the light source  10  and the direction controller element  30 . Or, the collimator element  20  adjusts the exit direction of the light from the light source  10  through reflection. For example, the collimator element  20  is provided with a reflective surface that can reflect the light emitted by the light source  10 , and by setting the curvature of the reflective surface, a reflection angle of the light can be adjusted, so that the exit direction of the light emitted by the light source  10  may be constrained within a preset angle range, even to adjust the light of the light source  10  to parallel light. For example, the reflective surface may be implemented by using a lamp cup structure, for example, it may be an inner reflective surface of a hollow lamp cup. 
     As shown in  FIG. 13 , the collimator element  20  includes a hollow lamp cup  22 . The hollow lamp cup  22  is a hollow housing with an inner reflective surface, and a direction of a port of the hollow lamp cup  22  faces the direction controller element  30 . The light source  10  is arranged at an end portion of the hollow lamp cup  22 , the end portion faces away from the port, and the inner reflective surface of the hollow lamp cup  22  is used to adjust the exit direction of the light from the light source  10 . For example, the inner reflective surface of the hollow lamp cup  22  may have a paraboloid shape, a free-form surface shape, a regular triangular pyramid shape, an isosceles triangular pyramid shape, or a cubic pyramid shape, etc. 
     Also, in order to more comprehensively collimate the light emitted by the light source  10 , for example, the collimator element  20  is provided with a reflective surface, and for example, is also provided with a collimating lens  21  and/or a collimating film. The collimating lens  21  and/or the collimating film are/is arranged inside the hollow lamp cup  22 , and a size of the collimating lens  21  and/or the collimating film is smaller than a size of the port of the hollow lamp cup. The collimating lens  21  and/or the collimating film are/is configured to collimate a portion of the light emitted by the light source  10  in the hollow lamp cup  22  and then emit the portion of the light to the direction controller element  30 . As shown in  FIG. 13 , the collimating lens  21  of the collimator element  20  collimates a portion of the light emitted by the light source  10  (i.e., the light indicated by a bold arrow in  FIG. 13 ), and the exit angle of the portion of the light is relatively small; while light with a larger exit angle emitted by the light source  10  (i.e., the light shown by a thin arrow in  FIG. 13 ) is collimated by the inner reflective surface of the hollow lamp cup  22 , so that the collimating lens  21  and the hollow lamp cup  22  may be combined to more effectively collimate the light emitted by the light source  10 . 
     Optionally, for example, the collimating lens  21  and/or the collimating film are/is also completely cover/covers the port of the hollow lamp cup  22 ; in this case, the hollow lamp cup  22  mainly plays a role of reflection, and the collimating lens  21  and/or the collimating film mainly plays a role of collimation.  FIG. 14  may be referred to for a structural schematic diagram of the collimator element  20 ; after the light with a larger exit angle (similar to the light shown by the thin arrow in  FIG. 13 ) emitted by the light source  10  is collimated by the hollow lamp cup, although the exit direction will change after passing through the collimating lens  21  again, due to characteristics of the light source  10  (e.g., the light source  10  is an LED lamp), most energy of the light emitted by the light source  10  is usually concentrated in a fan-shaped region, for example, the region corresponding to the bold arrow in  FIG. 13 , that is, most (e.g., about 80%) of the light emitted by the light source  10  is collimated by the collimating lens  21 . The collimating function may also be implemented based on the collimator element  20  shown in  FIG. 14 , and a fabrication process of the collimator element  20  is simple and convenient. Also, when there are a plurality of collimator elements  20 , the collimating lens  21  of each collimator element  20  may be cut, for example, into a regular triangle, a regular hexagon or a regular quadrilateral, so that the collimator element  20  may be closely arranged. 
     Optionally, due to the large number of collimator elements  20 , in order to simplify the fabrication process, for example, the collimator element  20  in this embodiment adopts a quadrangular frustum pyramid-shaped hollow housing with an inner reflective surface, that is, the collimator element  20  has a quadrangular frustum pyramid shape, and a cross-sectional shape or an opening shape of the collimator element  20  is quadrilateral, for example, it may be a parallelogram, a rectangle, a square, or a trapezoid. The collimator element  20  has an opening that gradually becomes larger; and the opening includes the port for light exit (light exit port) of the collimator element  20 . As shown in  FIG. 15 a    and FIG.  15   b , the light source  10  is arranged at a bottom end of the opening of the collimator element  20  (a left side of the collimator element  20  in  FIG. 15 a   ), and the light emitted by the light source  10  may be emitted out from the port (as shown on a right side of the collimator element  20  in  FIG. 15 a   ) after being reflected by the reflective surface inside the collimator element  20 . In addition, as described above, for example, a plurality of light sources  10  are also provided in the collimator element  20 . As shown in  FIG. 15 c   , for example, the plurality of light sources  10  is arranged in a matrix into a light source point array. In  FIG. 15 c   , there are six light sources  10  arranged in a 2×3 point array; or, as shown in  FIG. 15 d   , for example, the plurality of light sources  10  are arranged in a linear array, and three light sources  10  are arranged linearly in  FIG. 15   d.    
     Optionally, as shown in  FIG. 16 , the collimator element  20  is a roof-shaped lamp cup having the port; and the light sources  10  are arranged in a row at an end portion, away from the port, of the roof-shaped lamp cup; through the roof-shaped lamp cup, light emitted by a row of light sources  10  is uniformly emitted out along the port direction, so that the image source  1  can be provided with uniform light. 
     For example, in an embodiment of the present disclosure, as shown in  FIG. 17 , the collimator element  20  may include a lamp cup with a solid center  23 ; the lamp cup with a solid center  23  is a solid transparent component, and a refractive index of the solid transparent component is greater than  1 ; a direction of the port of the lamp cup with a solid center  23  faces the direction controller element  30 ; the light source  10  is arranged at an end, away from the port, of the lamp cup with a solid center  23 , and light emitted by the light source  10  is totally reflected when it is emitted to an inner surface of the solid transparent component. 
     In this embodiment, the lamp cup with a solid center  23  is a solid transparent component, and the direction of the port of the lamp cup with a solid center  23  refers to the port direction of the reflective surface  231  of the lamp cup with a solid center  23 . Referring to  FIG. 17 , the reflective surface  231  of the lamp cup with a solid center  23  is the inner surface of the solid transparent component; the solid transparent component is provided with a cavity  232  at an end portion away from the port, and the cavity  232  is configured to place the light source  10 , that is, the light source  10  is arranged at the bottom portion of the lamp cup that is away from the port of the lamp cup with a solid center; after the light emitted by the light source  10  is emitted to the reflective surface  231  of the lamp cup with a solid center  23 , since the refractive index of the lamp cup with a solid center  23  is greater than 1, and a peripheral medium of the lamp cup with a solid center  23  is air (whose refractive index is 1), when the light emitted by the light source  10  reaches the reflective surface  231  of the lamp cup with a solid center  23 , the light is emitted from an optically dense medium (i.e., the lamp cup with a solid center  23 ) to an optically thin medium (i.e., the air around the lamp cup with a solid center  23 ), and as long as an incident angle of the light emitted by the light source  10  and emitted to the reflective surface  231  reaches a preset angle, total reflection may occur; by setting a surface shape of the reflective surface  231  of the lamp cup with a solid center, the light emitted diagonally from the light source  10  may be collimated. For example, the reflective surface  231  of the lamp cup with a solid center is a free-form surface (i.e., it cannot be represented by a simple curved surface function mathematically), or a compound paraboloid (i.e., the reflective surface is composed of a plurality of paraboloids), both of which may well collimate the light emitted by the light source  10 , but it is not limited thereto. 
     For example, the collimating lens  21  may be integrated on the lamp cup with a solid center  23  to further improve the collimation effect. As shown in  FIG. 17 , the solid transparent component is provided with the cavity  232  at an end portion away from the port of the lamp cup with a solid center, and a surface, close to the port of the lamp cup with a solid center, of the cavity  232  is a convex surface  233 . Or, as shown in  FIG. 18 , a slot  234  is provided in a central position of the end portion, close to the port of the lamp cup with a solid center, of the solid transparent component, and the bottom surface of the slot  234  is a convex surface  235 . The lamp cup with a solid center  23  shown in  FIG. 17  or  FIG. 18  may be directly used as the collimator element  20 . 
     In this embodiment, the convex surface  233  of the cavity  232  or the convex surface  235  of the slot  234  is configured to collimate the light emitted by the light source  10 , that is, the convex surface  233  or the convex surface  235  is equivalent to a collimating lens  21 . The convex surface  233  or the convex surface  235  is arranged in the central position of the solid transparent component, and a size of the convex surface  233  or the convex surface  235  is smaller than a size of the opening the lamp cup with a solid center  23 . The convex surface  233  or the convex surface  235  is configured to collimate a portion of the light emitted by the light source  10  in the lamp cup with a solid center  23  and then emit the portion of the light to the direction controller element  30 . As shown in  FIG. 17 , the convex surface  233  is arranged in the cavity at a tail end of the lamp cup with a solid center; and the convex surface  233  may form a convex lens to collimate the light emitted to the convex surface  233 . Or, as shown in  FIG. 18 , the central position of the solid transparent component is provided with the slot  234 ; the bottom surface of the slot  234  is the convex surface  235 ; the convex surface  235  of the lamp cup with a solid center is configured to collimate light that cannot be reflected by the reflective surface  231  of the lamp cup with a solid center; and other light with a larger exit angle is totally reflected within the lamp cup with a solid center  23  and then collimated and emitted out of the lamp cup with a solid center  23 . A material of the lamp cup with a solid center  23  is a transparent material with a refractive index greater than 1, for example, a polymer transparent material, or glass, etc. 
     Optionally, for example, the collimating lens  21  and/or the collimating film are/is completely cover/covers the port of the lamp cup with a solid center  23 ; in this case, the lamp cup with a solid center  23  mainly plays a role of reflection, and the collimating lens  21  and/or the collimating film mainly plays a role of collimation. In this case,  FIG. 14  may be referred to for the structure of the collimator element  20 , a working principle thereof is also the same as the related content as described above, and no details will be repeated here. 
     On the basis of the above-described embodiments, when the first diffuser element  41  is the diffuser element of the discrete type and the collimator element  20  is the lamp cup with a solid center  23  with better light collimation effect, after the collimated light passes through the first diffuser element  41 , the light is diffused and scattered to a plurality of ranges, that is, the light is directly scattered to a plurality of regions, and each region corresponds to an observation range  200 . In this embodiment, in addition to diffusing the light, for example, the first diffuser element  41  of the discrete type is also separate the light into different observation ranges  200 , a process of separating the light into different observation ranges  200  is similar to the function of the direction controller element  30  controlling the direction of the light, both may control the direction of light, that is, the diffuser element may also play a role of direction control, and may emit light to the observation ranges  200  corresponding to different directions. 
     On the basis of the above-described embodiments, as shown in  FIG. 19 , the head-up display system further includes a polarization controller element  70 ; and the liquid crystal panel  50  includes a first polarizer  51 , a liquid crystal layer  52  and a second polarizer  53 . 
     For example, the first polarizer  51  and the second polarizer  53  are respectively arranged on two sides of the liquid crystal layer  52 , and the first polarizer  51  is arranged between the liquid crystal layer  52  and the light source  10 ; the first polarizer  51  is configured to transmit the first linearly polarized light; and the second polarizer  53  is configured to transmit the second linearly polarized light, a polarization direction of the second linearly polarized light is perpendicular to a polarization direction of the first linearly polarized light. The polarization controller element  70  is arranged between the light source  10  and the first polarizer  51 , the polarization controller element  70  is configured to transmit the first linearly polarized light and reflect or absorb the second linearly polarized light. 
     In an embodiment of the present disclosure, upper and lower sides of the liquid crystal layer  52  of the liquid crystal panel  50  are respectively provided with polarizers with polarization states perpendicular to each other, that is, the first polarizer  51  and the second polarizer  53 ; the first linearly polarized light can pass through the first polarizer  51 , the second linearly polarized light can pass through the second polarizer  52 , and the polarization direction of the first linearly polarized light is perpendicular to the polarization direction of the second linearly polarized light. Since the light emitted by the light source  10  is generally non-polarized light, that is, about 50% of the light may be absorbed by the first polarizer  51  between the liquid crystal layer and the light source  10 , and the polarizer is generally attached to a surface of the liquid crystal layer  52 , the portion of light energy will cause the first polarizer  51  and the liquid crystal layer  52  to generate heat, which affects the service life of the liquid crystal panel  50 . 
     According to an embodiment of the present disclosure, the polarization controller element  70  is provided between the light source  10  and the first polarizer  51 ; and the polarization controller element  70  can transmit the first linearly polarized light and reflect or absorb the second linearly polarized light, so that light that can reach the first polarizer  51  is only the first linearly polarized light, so as to prevent the first polarizer  51  from absorbing the second linearly polarized light and prevent the liquid crystal panel  50  from absorbing heat, thereby prolonging the service life of the liquid crystal panel  50 . For example, the second linearly polarized light in the light emitted by the light source  10  may be absorbed by the polarization controller element  70 , in a case where there is a certain distance between the polarization controller element  70  and the liquid crystal panel  50 . In addition, if the polarization controller element  70  can reflect the second linearly polarized light, for example, the reflected second linearly polarized light is reflected to the polarization controller element  70  again by reflection of other components (e.g., the reflective surface of the collimator element  20 , etc.), and a portion of the light may be converted into the first linearly polarized light, so that more light may be used for imaging of the liquid crystal panel  50 , thereby improving the light utilization rate. 
     Optionally, the polarization controller element  70  is a reflection-type polarized reflective film, illustratively a dual brightness enhancement film (DBEF), a brightness enhancement film (BEF), or a photonic crystal having polarization and incident angle selective transmittance, etc., and when the polarization controller element  70  can reflect the second linearly polarized light, for example, the polarization controller element  70  is attached to an outer surface of the liquid crystal panel  50 . 
     On the basis of the above-described embodiments, referring to  FIG. 20 , the head-up display system further includes: a light blocking layer  80 ; the light blocking layer  80  is arranged on a side of the liquid crystal panel  50  that is away from the light source  10 , and the light blocking layer  80  is configured to limit an exit angle of the light emitted from the liquid crystal panel  50 . 
     According to an embodiment of the present disclosure, the light blocking layer  80  includes a plurality of light blocking gratings with a preset height, and a grating array is formed by a plurality of protruding light blocking gratings to physically block propagation of light in certain directions. By designing a height and a width of the light blocking grating, an angle at which the observer can view the light may be restricted. As shown in  FIG. 20 , the light blocking layer  80  restricts the light to a viewing angle α, thereby forming an observable region; that is, a human eye E 1  is located in the observable region, and in this case, the light emitted by the light source  10  can be seen; however, a human eye E 2  is located outside the observable region, so that the human eye E 2  cannot see the light emitted by the light source  10 , and the human eye E 2  cannot observe an image of the liquid crystal panel  50 . 
     According to this embodiment, for example, the light blocking layer  80  is a layer of grating array, and the grating array may be horizontal, vertical, or at any angle, so that only light in a direction parallel to the grating may pass through. For example, the viewing angle of the light blocking layer  80  is 48 degrees, 60 degrees, 75 degrees, or any other angle required. In addition, for example, the light blocking layer  80  is an orthogonal stack of two layers of grating arrays, or a stack of two layers of gratings staggered at a certain angle. For example, a grating array of each layer is horizontal, vertical, or at any angle. For example, the viewing angle is 48 degrees, 60 degrees, 75 degrees, or any other angle required. For example, the light blocking layer  80  may be an anti-peeping grating. 
     According to an embodiment of the present disclosure, the light blocking layer  80  is added to the outer surface of the liquid crystal panel  50 , which may limit a light exit angle and achieve certain special purposes; for example, an image source 1 without the light blocking layer  80  is provided at a surface of a vehicle console, so that a driver can see the image of the liquid crystal panel  50  and an image reflected by the windshield at the same time, which affects the driver driving the vehicle. The light blocking layer  80  can make the light exit only toward the direction of the windshield, and the image of the liquid crystal panel  50  per se cannot be seen from the driver&#39;s perspective, which can prevent the image of the liquid crystal panel  50  per se from affecting driving. 
     Optionally, referring to  FIG. 21 , the head-up display system further includes a light scattering layer  90 ; the light scattering layer  90  is arranged on a side, faces away from the liquid crystal panel  50 , of the light blocking layer  80 , and the light scattering layer  90  is configured to scatter external ambient light. In an embodiment of the present disclosure, a light scattering layer  90  is provided on an outside of the light blocking layer  80 , which may scatter external ambient light, for example, sunlight, etc., which may prevent glare caused by external sunlight irradiating a surface of the light blocking layer  80 . For example, the combination of the light scattering layer  90  and the light blocking layer  80  may be formed in a one-piece manner, for example, a frosted anti-peeping grating. 
     In addition, it is to be noted that, in all the above-described embodiments, in order to facilitate description of the structure of the head-up display system, or to facilitate description of a propagation situation or direction of light, there is a certain distance between respective elements, for example, there is an interval between the direction controller element  30  and the first diffuser element  41  in  FIG. 1 , which is not used to limit that there must be an interval between the two, that is, for example, the direction controller element  30  and the first diffuser element  41  are attached to each other, or the gap between the two is very small. Other two adjacent elements also follow the arrangement mode, unless it is specifically stated that a certain distance between the two elements is required, for example, an interval is to be between the first diffuser element  41  and the second diffuser element  42  as described above. In addition, the drawings in the above-described embodiments are only schematic structural diagrams, which only schematically show sizes of respective elements, and do not represent an actual size proportion. 
     In the above-described embodiments of the present disclosure, with respect to the diffuser element, only the first diffuser element may be provided, or the first diffuser element and the second diffuser element may also be provided. In a case where only the first diffuser element is provided, for example, the first diffuser element is referred to as the diffuser element. In a case where the first diffuser element and the second diffuser element are provided, the diffuser element includes the first diffuser element and the second diffuser element. It can be understood that, the number of diffuser elements may be set to more than two according to needs. 
     In the above-described embodiments of the present disclosure, the direction controller element  30  is, for example, the light concentrator element. In the embodiments of the present disclosure to be described below, for example, the direction controller element  108  includes a collimator element, or for example also includes other elements such as a light concentrator element. 
     An embodiment of the present disclosure further provides a light control apparatus, as shown in  FIG. 22 , which includes: a diffuser element  106  and a direction controller element  108 . 
     The direction controller element  108  is configured to concentrate the light emitted by light sources in different positions, that is, concentrate the light to a same preset position  1062 ; the diffuser element  106  is provided on a side, faces away from the light source, of the direction controller element  108 , and the diffuser element  106  is configured such that the light from the direction controller element  108  is diffused and then form a light spot  1061  with a preset shape. The light spot  1061  corresponds to the first preset region. 
     For example, a plurality of direction controller elements  108  are used to implement concentration of light. For example, referring to  FIG. 22 , light sources  104  are arranged in different positions; in  FIG. 22 , it is illustrated by taking 7 light sources  104  being provided as an example; correspondingly, 7 direction controller elements  108  are provided to control a direction of light emitted by the light source  104 . As shown in  FIG. 22 , a direction controller element  108  is provided for each light source  104 . As shown in  FIG. 22 , without the diffuser element  106 , the direction controller element  108  concentrates light emitted by a plurality of light sources  104  to a preset position  1062 . The preset position  1062  corresponds to a second preset region. An area of the second preset region is smaller than an area of the first preset region. For example, in  FIG. 22 , it is illustrated by taking  1062  being a point position as an example; the preset position  1062  in this embodiment may also be a small region, that is, it is only necessary to concentrate the light emitted by the light source  104  into the region. For example, each direction controller element  108  is similar to a small light control apparatus, and a direction of the light emitted by the light source  104  is adjusted by setting orientations of the direction controller elements  108  in different positions, so as to implement light concentration. 
     At the same time, if light at different positions is only concentrated to the preset position  1062  of a small range, when the light control apparatus is applied to the light source of the image source, the image source can only image in a small range, which is inconvenient for an observer to view an image formed by the image source. In this embodiment, the light is diffused by the diffuser element  106  to form the light spot  1061  with a preset shape and a larger imaging range, so that it is convenient for the observer to view an image formed by the image source in a large range. For example, the direction controller element  108  at leftmost side of  FIG. 22  is taken as example to illustrate. As shown in  FIG. 22 , in a case where the diffuser element  106  is not provided, light A emitted by the light source  104  on the leftmost side can be irradiated to the preset position  1062  along an optical path a; after the diffuser element  106  is arranged outside the direction controller element  108 , the light A is scattered into a plurality of rays of light (including light A 1 , light A 2  and the like) by the diffuser element  106  and scattered into one range, i.e., the light spot  1061 , so that it is convenient for the observer to view the image formed by the image source in the range of the light spot  1061 . Optionally, for example, the diffuser element  106  is a diffractive optical element (DOE), e.g., a beam shaper; the size and the shape of the light spot are determined by the microstructure of the beam shaper, the shape of the light spot includes, but is not limited to, a circle, an oval, a square, a rectangle or a batwing shape. For example, the diffusing angle of the light spot after diffusion in the side view direction is 10 degrees, and further for example, is 5 degrees, but it is not limited thereto; and the diffusing angle in the front view direction is 50 degrees, and further for example, is 30 degrees, but it is not limited thereto. For example, the side view direction is the left-and-right direction or the horizontal direction, and for example, the front view direction is the up-and-down direction or the vertical direction. 
     For example, there are many direction controller elements  108 , different direction controller elements  108  are arranged at different positions and used for adjusting the exit directions of light emitted by light sources at different positions, and the exit directions of the light emitted by the light sources at different positions all point to the same preset position. As shown in  FIG. 22 , there are seven direction controller elements  108  in  FIG. 22 . For example, one direction controller element  108  can adjust the light emitted by one light source  104 , or can adjust the light emitted by a plurality of light sources  104 , and this embodiment is not limited in this aspect. Namely, one or more light sources  104  may be arranged in one direction controller element  108 . 
     Those skilled in the art can understand that in  FIG. 22 , the diffusing effect of the diffuser element  106  is just schematically illustrated, the diffuser element  106  can diffuse the light into the range of the light spot  1061 , but does not completely limit the light emitted by the light source  104  in the light spot  1061 . Namely, after passing through the diffuser element  106 , the light A may form a light spot of a larger range, the light emitted by other light sources  104  may form other light spots through the diffuser element  106 , but the light emitted by all the light sources  104  all can reach the light spot  1061 . 
     In the light control apparatus provided by the embodiments of the present disclosure, the light at different positions is concentrated to the same position by the direction controller element, so that the brightness of the light can be improved; and the light is diffused by the diffuser element, so that the light spot with the preset shape can be formed and it is convenient to subsequently image in the range of the light spot, so that while the brightness of the light is improved, the imaging range can also be extended. In addition, the light source can provide light with sufficient brightness without high power, so that the heat dissipation requirement for a device of the light source can be reduced. 
     Based on the above-mentioned embodiment, as shown in  FIG. 23 , the direction controller element  108  includes a collimator element  107 , the collimator element  107  can collimate the light emitted by the light source  104 , i.e., collimate the light irradiated to different directions by the light source, so that the light emitted by the direction controller elements  108  is consistent or basically consistent in direction. 
     For example, the collimator element  107  is a collimating lens, the collimating lens includes one or more of a convex lens, a concave lens, a Fresnel lens or a combination thereof, and for example, the lens combination is a combination of the convex lens and the concave lens, or a combination of the Fresnel lens and the concave lens, or the like; or the collimator element  107  is a collimating film, and configured to adjust the exit direction of the light into a preset angle range. In this case, the distance between the collimator element  107  and the position of the light source  104  is equal to a focal length of the collimator element  107 , i.e., the light source  104  is arranged at the focal point of the collimator element  107 . 
     Optionally, as shown in  FIG. 22 , for example, concentration of the light at different positions is implemented by adjusting the exit direction of the direction controller element  108 . Or, for example, concentration of the light is implemented by a light concentrator element. With reference to  FIG. 23 , the direction controller element  108  further includes a light concentrator element  105 ; and the light concentrator element  105  is arranged between the light source  104  and the diffuser element  106 . When the direction controller element  108  includes the collimator element  107 , the light concentrator element  105  is arranged between the collimator element  107  and the diffuser element  106 ; and the light concentrator element  105  is configured to concentrate different light to the same preset position  1062 . Namely, even though the orientation of the direction controller element  108  is not specifically set, different light can also be concentrated to one preset position  1062  by the light concentrator element  105 . For example, as shown in  FIG. 23 , for the light concentrator element  105 , a plurality of collimator elements  107  can be correspondingly arranged. 
     Based on the above-mentioned embodiment, with reference to  FIG. 20 , the light control apparatus further includes the light blocking layer  80 , and specifically, it may refer to  FIG. 20  and the above-mentioned related description, which is not repeated herein. 
     In addition, the light blocking layer  80  is to be arranged on the outer surface of an device for displaying. For example, when a liquid crystal display uses the light control apparatus provided by this embodiment as a backlight source, the light blocking layer  80  is arranged on the outer surface of the liquid crystal display, and in this case, an image formed by the liquid crystal display can be blocked, i.e., only an observer in an observing region can see the image formed by the liquid crystal display. 
     Optionally, for example, the light control apparatus is used in a HUD to implement light control on the HUD; and by the light blocking layer  80 , a driver can be prevented from directly viewing a screen of the HUD. With reference to  FIG. 24 , the height direction of a light blocking gratings of the light blocking layer  80  faces a windshield  701 . For example, the height direction of the light blocking gratings refers to the direction of the light blocking element from one side of the light source  104  to the outside of the light control apparatus, also refers to the direction of exit light of the light control apparatus; and in  FIG. 24 , the light blocking gratings are represented with small rectangles, and the length direction of the rectangle is the above-mentioned “height direction of the light blocking gratings”. When the HUD works, a real image can be formed on the surface of the screen, a virtual image can also be formed through the windshield  701 , and due to the arrangement of the light blocking layer  80 , eyes E 3  of the driver cannot view the real image on the screen of the HUD, and can only view the virtual image formed by the HUD through the windshield  701 ; that is, the screen of the HUD cannot be directly viewed from the position of the user, so that when the user drives a vehicle, it can be avoided that the viewing field of the user is influenced or the user is dizzied due to the brightness when the real image is formed on the screen of the HUD, and thus, safety in the driving process can be improved. 
     Also, in this embodiment, each direction controller element  108  in  FIG. 22  and  FIG. 23  further includes a reflecting element; and the reflecting element is configured to reflect the light emitted by the light source  104  to the diffuser element  106 . 
     For example, the reflecting element includes a lamp cup; the lamp cup is a hollow housing surrounded by a reflective surface, and the opening direction of the lamp cup faces the diffuser element  106 ; and the bottom of the lamp cup, which is away from an opening, is used for arranging the light source  104 . For example, the inner wall (i.e., the inner wall of a groove of the reflecting element) of the lamp cup is the reflective surface of the lamp cup. 
     In addition, as shown in  FIG. 23 , the direction controller element  108  further includes: a collimator element  107 ; the collimator element  107  is arranged inside the lamp cup, and the size of the collimator element  107  is smaller than the size of the opening of the lamp cup; and the collimator element  107  is configured to collimate part of light emitted by the light source in the lamp cup and then emit the collimated light to the diffuser element  106 . 
     For example, in some other embodiments, the lamp cup is the lamp cup with a solid center, i.e., the lamp cup is a solid transparent component with the reflective surface, and the refractive index of the solid transparent component is greater than 1; the opening direction of the lamp cup with a solid center faces the diffuser element  106 ; and the tail end of the lamp cup with a solid center, which is away from an opening, is used for arranging the light source  104 . The specific structure of the lamp cup with a solid center can refer to  FIG. 17  and  FIG. 18 , and is not repeated herein. 
     Based on the same inventive concept, another embodiment of the present disclosure further provides a passive light-emitting image source. With reference to  FIG. 25  or  FIG. 26 , the passive light-emitting image source includes a light control apparatus  100 , a light source  104  and a liquid crystal layer  200 . The light source  104  and the liquid crystal layer  200  are arranged on two sides of a direction controller element  108  of the light control apparatus  100 . 
     In this embodiment, for example, a liquid crystal material in the liquid crystal layer  200  is illustratively a common liquid crystal, e.g., a twisted nematic (TN) liquid crystal, a high twisted nematic (HTN) liquid crystal, a super twisted nematic (STN) liquid crystal, a formated super twisted nematic (FSTN) liquid crystal, or the like; or, for example, the liquid crystal layer  200  is a blue phase liquid crystal. For example, the light source  104  is an electroluminescent device, e.g., a light emitting diode (LED), an incandescent lamp, a laser, a quantum dot light source, or the like, or for example, may be an organic light-emitting diode (OLED), a Mini LED, a Micro LED, a cold cathode fluorescent lamp (CCFL), an electroluminescent display (ELD), a cold LED light source (CLL), an electro luminescent (EL) device, a field emission display (FED), a halogen tungsten lamp, a metal halide lamp, or the like. 
     The working principle of the passive light-emitting image source provided by this embodiment is basically similar to the principle of a common passive light-emitting image source. For example, after light emitted by the light source  104  is processed through the light control apparatus  100 , the light is provided for the liquid crystal layer  200 ; that is to say, the combination of the light control apparatus  100  and the light source  104  can be regarded as the backlight source for providing the light for imaging of the liquid crystal layer  200 . The liquid crystal layer  200  includes liquid crystals, and based on the characteristics of the liquid crystal layer  200 , the liquid crystal layer  200  can deflect linearly polarized light. 
     In addition, the light control apparatus  100  can collimate and diffuse the light emitted by the light source  104 . With reference to  FIG. 26 , by the collimating and diffusing effect of the light control apparatus  100  on the light, the liquid crystal layer  200  can form a light spot with a preset shape at a preset position  1061 , and in  FIG. 26 , a rectangular light spot is shown as an example. Namely, an observer can observe a clear image formed by the liquid crystal layer  200  at the preset position  1061 . Also, in  FIG. 26 , it is illustrated by taking a case that a diffuser element  106  is arranged below the liquid crystal layer  200  (the diffuser element  106  is arranged on one side of the liquid crystal layer  200  close to the light source  104 ) as an example; or, for example, the diffuser element  106  is arranged on one side of the liquid crystal layer  200  away from the light source  104 , which can also achieve the same diffusing effect. 
     The HUD technology adopts an optical reflection principle to project vehicle information such as vehicle speed on a windshield or other glass, which may avoid distraction caused by a driver looking down at a dashboard during driving, thereby bringing a better driving experience while improving a driving safety factor. A common windshield HUD image source is mostly a liquid crystal display (LCD). If the HUD adopts the common LCD image source, the brightness of an HUD image displayed on the windshield is low; and generally, the brightness of the LCD image source is increased to ensure the brightness of the HUD image displayed on the windshield, which not only leads to higher power consumption of the image source, but also causes greater heat generation, increasing heat dissipation requirements for HUD. In addition, the viewing field angle and a display region of a common light source of the HUD can be extended on the basis of an optical design method of a free-form reflector, which also can cause the problems of insufficient brightness, or the like, and if the brightness of the image is ensured, the light source may generate high electrical power consumption. If the passive light-emitting image source provided by this embodiment is applied to the HUD, the light exit angle of the image source can be controlled, and the light is limited to be within the light spot range, so that the utilization rate and the light transmittance of the light emitted by the light source are improved, the high-brightness light can be emitted by the low-power light source, it is convenient for subsequent high-brightness imaging, and energy consumption of the light source is reduced; and due to improvement of the light transmittance, the light control apparatus cannot absorb a large amount of light energy, generates less heat, and has lower heat dissipation requirements for the HUD. 
     For example, as shown in  FIG. 25 , the included angles between planes where light exit ports of a plurality of light control apparatuses  100  are positioned and the liquid crystal layer  200  are the same. For example, the planes where the light exit ports of the plurality of light control apparatuses  100  are positioned are parallel to the liquid crystal layer  200 . Such a setting mode is beneficial for placing the plurality of light control apparatuses  100 . As shown in  FIG. 25 , the plurality of light control apparatuses  100  are sequentially arranged. 
     For example, as shown in  FIG. 26 , the plurality of light control apparatuses  100  are sequentially arranged, and the included angles between the planes where the light exit ports of the plurality of light control apparatuses  100  are positioned and the liquid crystal layer  200  are different. As shown in  FIG. 26 , the included angles between the planes where the light exit ports of the plurality of light control apparatuses  100  are positioned and the liquid crystal layer  200  are gradually increased. 
     Based on the above-mentioned embodiment, with reference to  FIG. 27 a   , the light source  104  is an electroluminescent array consisting of one or more electroluminescent modules  1041 , and each electroluminescent module  1041  includes one or more electroluminescent devices  1042 . In  FIG. 27 a   , it is illustrated by taking a case that one electroluminescent module  1041  includes six electroluminescent devices  1042  as an example. The light control apparatus  100  includes one or a plurality of reflecting elements, and each electroluminescent module  1041  is correspondingly provided with one reflecting element (for example, the reflecting element is the inner surface of a hollow lamp cup). Namely, in this embodiment, for the reflecting element, for example, one electroluminescent device  1042  is correspondingly arranged, or, for example, a plurality of electroluminescent devices  1042  are arranged, and it can be determined according to actual situations. For example, the electroluminescent device may be an incandescent lamp, an LED, a laser, a quantum dot light source, or the like. 
     In this embodiment,  FIG. 27 a    is a top view of the passive light-emitting image source, and  FIG. 27 a    shows a representation form of the electroluminescent array. For example, the electroluminescent device  1042  is located in the light control apparatus  100 , so the backlight source shape of the passive light-emitting image source is decided by the light control apparatus  100 . The electroluminescent device  1042  is generally a point light source, so the light emitted by the electroluminescent device  1042  can be the most efficiently utilized by adopting a circular light control apparatus  100  (for example, a lamp cup with a circular port is provided in the light control apparatus  100 ); and when the circular light control apparatuses  100  are arranged, there is a gap between two light control apparatuses, so that the space utilization rate is reduced. In order to balance the light utilization rate and the space utilization rate, for example, the electroluminescent array illustratively adopts a regular hexagonal arrangement mode, as shown in  FIG. 27 b   ; and the regular hexagonal arrangement mode improves the space utilization rate, and reduces the light utilization rate. Optionally, the electroluminescent array adopts a regular octagonal arrangement mode, as shown in  FIG. 27 c    and  FIG. 27 d   , the gaps can be filled with the small regular octagonal light control apparatuses  100 , and the regular octagon is closer to the circle than the regular hexagon, so the light utilization rate is higher, and compared to the circular array, the regular octagonal electroluminescent array also has the higher space utilization rate. 
     Based on the above-mentioned embodiment, with reference to  FIG. 28 , the passive light-emitting image source includes a plurality of sets of light control apparatuses  100 ; and different light control apparatuses  100  are configured to emit the light emitted by the light source  104  to different directions or regions. As shown in  FIG. 28 , it is illustrated by taking a case that the passive light-emitting image source includes two sets of light control apparatuses  100  as an example, and by control of the light control apparatuses  100  on the light emitted by the light source  104 , different images formed by the liquid crystal layer  200  can be viewed at different positions or in different regions. In  FIG. 28 , in order to distinguish two light control apparatuses  100 , the light exit directions of two light control apparatuses  100  are different; and those skilled in the art can understand that the two light control apparatuses  100  correspond to different positions of the liquid crystal layer  200 , so even though the light exit directions of the two light control apparatuses  100  are the same (for example, both the light exit directions are perpendicular to the liquid crystal layer  200 ), two eye box ranges can be formed. The light control apparatus  100  in this embodiment may be the light control apparatus in any one of the embodiments in  FIG. 22  to  FIG. 24 . For example, the eye box range refers to a region where the observer can observe an image presented by the light spot. 
     For example,  FIG. 29  can be referred to for the schematic diagram in which the observer views the image of the passive light-emitting image source, the passive light-emitting image source is an LCD display apparatus which includes two sets of light control apparatuses, an eyebox range E 01  and an eyebox range E 02  are respectively formed, an observer located in the eyebox range E 01  can only see the image of the left portion of the passive light-emitting image source, and an observer in the eyebox range E 02  can only see the image of the right portion of the passive light-emitting image source. Different imaging on multiple observers can be implemented by arranging a plurality of light control apparatuses  100  to facilitate viewing different image contents by different observers.  FIG. 29  shows a central axis point P. Two images are viewed at the central axis point P, i.e., a crosstalk image is formed. A region where two images can be simultaneously viewed is a crosstalk region. 
     Optionally, the light control apparatus  100  is provided with the diffuser element  106 , and a large light spot is formed through the diffuser element  106 , so that observers at different positions can also observe the image formed by the passive light-emitting image source. In order to improve the utilization rate for the light emitted by the light source  104 , the diffuser element  106  is configured to form a batwing-shaped light spot (a light spot with a shape similar with an infinity symbol “∞”), i.e., by the diffuser elements  106 , one set of light control apparatus can form the light spot with two main regions, i.e., the eyebox range E 01  and the eyebox range E 02 , so that the observers in both the eyebox range E 01  and the eyebox range E 02  can view the image formed by the passive light-emitting image source, and  FIG. 30  can be referred to for the schematic diagram of imaging in this case. 
     Based on the above-mentioned embodiment, the light emitted by the light control apparatus  100  in the passive light-emitting image source is reflected to human eyes through the reflection device  700 , so as to form a high-brightness virtual image VT outside the reflection device  700 , and  FIG. 31  can be referred to for the schematic diagram of imaging thereof. For example, the reflection device  700  may be a transparent material, e.g., a common glass, a quartz glass, an automobile windshield, a transparent resin plat, or the like, or may be a non-transparent material, e.g., a plane/concave/convex/free-form mirror coated with a reflecting layer, a reflecting film, a smooth metal reflective surface, or the like. 
     In a case that there are multiple observers, when a plurality of light control apparatuses  100  are adopted, the schematic diagram of imaging thereof refers to  FIG. 32 a   , and in  FIG. 32 a   , two light control apparatuses  100  form two light spots, i.e., two eye box ranges E 01  and E 02 . When the diffuser element with the large light spot (e.g., a large rectangular light spot or a batwing light spot, or the like) is adopted,  FIG. 32  can be referred to for the schematic diagram of imaging of the light control apparatus  100 ; and  FIG. 32 b    shows the schematic diagram in which one set of light control apparatus  100  forms the batwing light spot (the light spot with the shape similar with the infinite symbol “∞”) through the diffuser element. For example, in  FIG. 32 a    and  FIG. 32 b   , an LCD imaging mode is illustrated exemplarily.  FIG. 32 a    shows the central axis point P. 
     Based on the above embodiment, the liquid crystal layer  200  includes an RGB filter, and the passive light-emitting image source can emit R (read), G (greed), B (blue) three-color light through the RGB filter, thereby forming a color image. 
     For example, in some embodiments, the color image is implemented by a blue phase liquid crystal. For example, a liquid crystal layer  300  in this embodiment is the blue phase liquid crystal, and the light sources  104  include a red light source, a green light source and a blue light source; the red light source, the green light source and the blue light source work periodically, and do not work simultaneously. For example, the light sources (the red light source, the green light source and the blue light source) of three colors can form RGB backlight, and the three light sources do not work simultaneously, that is, the light source of only one color emits light at different time at most, that is, the blue phase liquid crystal can emit light of one color at a certain time point. Since the blue phase liquid crystal has a fast response speed, and the switching speed of the light sources (such as LED) is also very fast, and since human eye has a delay of about 0.2 second when recognizing a color, the human eyes can receive red, green and blue by quickly switching the light sources and correspondingly controlling a working state of the blue phase liquid crystal, and after being integrated by the human eye, the red, green and blue can synthesize multiple colors (such as yellow, magenta, white, etc.), so that people feel that they see a color image. At the same time, only one third of the light sources of the blue phase liquid crystal work, and there is no need for a color filter, which can reduce power consumption of the light sources; and one pixel of the blue phase liquid crystal can form a color pixel (a traditional liquid crystal needs three pixels), which can increase pixel density, so that definition and resolution of imaging are increased. 
     Based on the above embodiments, for example, the passive light-emitting image source is used as a 3D image source for the observer to view a 3D image or video. For example, referring to  FIG. 33 , the passive light-emitting image source further includes a liquid crystal conversion layer  201 ; and the liquid crystal conversion layer  201  is arranged on the side of the liquid crystal layer  200  away from the light sources  104 . For example, the liquid crystal conversion layer  201  is arranged on the outer side of the liquid crystal layer  200  or the inner side of the liquid crystal layer  200 , which is not limited by this embodiment. In  FIG. 33 , it is illustrated by taking a case that the liquid crystal conversion layer  201  is arranged on the outer side of the liquid crystal layer  200  as an example. 
     For example, the liquid crystal conversion layer  201  includes a plurality of liquid crystal units  2011  that are spaced, and one liquid crystal unit  2011  in the liquid crystal conversion layer  201  corresponds to one liquid crystal unit  2001  in the liquid crystal layer  200 ; the liquid crystal units  2001  of the liquid crystal layer  200  are configured to convert light in a first polarization direction into light in a second polarization direction, and the liquid crystal units  2011  of the liquid crystal conversion layer  201  are configured to convert the light in the second polarization direction into the light in the first polarization direction, and the first polarization direction is perpendicular to the second polarization direction. 
     In this embodiment, for example, the liquid crystal layer  200  uses a conventional liquid crystal, one liquid crystal unit  2001  of the liquid crystal layer  200  corresponds to one pixel, and when the liquid crystal conversion layer  201  is not arranged, the liquid crystal layer  200  can normally display a 2D image. The additional liquid crystal conversion layer  201  in this embodiment is a device consisting of the liquid crystal units  2011  that are spaced apart, and each liquid crystal unit  2011  of the liquid crystal conversion layer  201  corresponds to one liquid crystal unit  2001  in the liquid crystal layer  200 . As shown in  FIG. 33 , the liquid crystal layer  200  includes 16 liquid crystal units  2001 : A 1 -A 4 , B 1 -B 4 , C 1 -C 4  and D 1 -D 4 , and the liquid crystal conversion layer  201  includes 8 liquid crystal units  2011 : a 1 , a 3 , b 2 , b 4 , c 1 , c 3 , d 2  and d 4 , and for example, the liquid crystal unit a 1  corresponds to the liquid crystal unit A 1 , the liquid crystal unit a 3  corresponds to the liquid crystal unit A 3 , and so on. By providing the liquid crystal conversion layer  201 , the liquid crystal units of the liquid crystal layer  200  are divided into two parts, and one part of the liquid crystal units correspond to the liquid crystal conversion layer  201 , for example, 8 liquid crystal units such as the liquid crystal units A 1 , A 3 , B 2  and B 4 ; while the remaining liquid crystal units do not correspond to the liquid crystal conversion layer  201 , for example, 8 liquid crystal units such as the liquid crystal units A 2 , A 4 , B 1  and, B 3 . In an actual production process, the liquid crystal units of the liquid crystal conversion layer  201  can be fixedly connected by a transparent material, and for example, the transparent material is arranged between the liquid crystal unit a 1  and the liquid crystal unit c 1 , so that the entire liquid crystal conversion layer  201  can be manufactured into a whole without influencing the liquid crystal unit B 1  of the liquid crystal layer  200  emitting light outward. 
     Also, although the liquid crystal layer  200  and the liquid crystal conversion layer  201  are essentially both liquid crystals, their polarization characteristics are not exactly the same. For example, the liquid crystal layer  200  is configured to convert the light in the first polarization direction into the light in the second polarization direction, and the liquid crystal conversion layer  201  is configured to convert the light in the second polarization direction into the light in the first polarization direction; for example, the first polarization direction is perpendicular to the second polarization direction. 
     Referring to  FIG. 33 , light emitted by the light sources  104  includes the light in the first polarization direction, or the light emitted by the light sources  104  can be converted into more light in the first polarization direction after passing through the light control apparatus  100 . On the work principle of a liquid crystal, a polarization state of light will be changed during liquid crystal imaging, that is, linearly polarized light in a preset polarization direction will be converted into linearly polarized light perpendicular to the preset polarization direction after passing through the liquid crystal, and the specific preset polarization direction is determined by characteristics of the liquid crystal itself. The liquid crystal layer  200  and the liquid crystal conversion layer  201  in this embodiment adopt two different liquid crystals. For example, the light emitted by the light sources  104  are converted into light with a second polarization characteristic after passing through the liquid crystal layer  200 , and then the light will be converted into light with a first polarization characteristic after passing through the liquid crystal conversion layer  201 , while the liquid crystal layer not blocked by the liquid crystal conversion layer  201  still emits the light with the second polarization characteristic. Therefore, in  FIG. 33 , the liquid crystal units a 1 , a 3  and the like emit the light with the first polarization characteristic, and the liquid crystal units A 2 , A 4  and the like emit the light with the second polarization characteristic, that is, one part of pixels of the passive light-emitting image source of this embodiment emit the light with the first polarization characteristic, and the other part of pixels emit the light with the second polarization characteristic. 
     When the observer needs to view a 2D image, the liquid crystal layer  200  and the liquid crystal conversion layer  201  both work, and since the human eyes cannot distinguish light in different polarization states, the liquid crystal conversion layer  201  in this case is transparent, so that the observer can view the 2D image normally. When the observer needs to view a 3D image, the liquid crystal layer  200  and the liquid crystal conversion layer  201  still work normally, but it is necessary that different liquid crystal units of the liquid crystal layer are controlled to display different images, and the observer needs to wear polarized stereoscopic glasses, so that the left eye LE of the observer can view part of the image, and the right eye RE can view the other part of the image, and a 3D sense is brought to the observer by parallax between the two parts of the image. The polarized stereoscopic glasses are an existing mature technology, which will not be repeated here. 
     In addition, in an actual scene, it is hard that light passes through the liquid crystal conversion layer  201  completely, that is, the liquid crystal conversion layer  201  cannot be fully transparent during operation, thus causing brightness of the light passing through the liquid crystal conversion layer  201  to be relatively low. As shown in  FIG. 33 , brightness of light from the liquid crystal unit B 1  is relatively high, and brightness of light from the liquid crystal unit a 1  is relatively low due to the fact that the light passes through two layers of liquid crystals (i.e., the liquid crystal unit A 1  and the liquid crystal unit a 1 ). For example, the liquid crystal layer  200  includes 1000 liquid crystal units, 500 liquid crystal units of which are covered with the liquid crystal conversion layer  201 , and the other 500 liquid crystal units are not provided with a liquid crystal conversion layer correspondingly, so that the brightness of the light from the  500  liquid crystal units covered with the liquid crystal conversion layer  201  is relatively low. 
     In order to guarantee imaging brightness uniformity of the image source, the total area of all the liquid crystal units in the liquid crystal conversion layer  201  is not less than half of the total area of all the liquid crystal units in the liquid crystal layer  200 , that is, for the liquid crystal layer  200 , the number of the liquid crystal units (such as A 1 , C 1  and the like) corresponding to the liquid crystal conversion layer  201  is greater than or slightly greater than the number of the liquid crystal units (such as B 1 , D 1  and the like) not corresponding to the liquid crystal conversion layer  201 , which can increase overall brightness of the liquid crystal conversion layer  201 , so that the overall brightness is more uniform. For example, the liquid crystal layer  200  includes 1000 liquid crystal units, 550 liquid crystal units of which are covered with the liquid crystal conversion layer  201  (that is, the liquid crystal conversion layer  201  includes 550 liquid crystal units that are spaced apart), and the other 450 liquid crystal units in the liquid crystal layer  200  are not provided with the liquid crystal conversion layer  201  correspondingly; in the liquid crystal layer  200 , by increasing a proportion of the liquid crystal units corresponding to the liquid crystal conversion layer  201  in the liquid crystal layer  200 , the overall brightness of the liquid crystal units in the liquid crystal layer  200  is increased. 
     It is to be noted that the purpose of “spaced apart” in this embodiment is to uniformly arrange the liquid crystal units of the liquid crystal conversion layer  201 , so that a proportion between the liquid crystal units (such as A 1 , A 3  and the like) which are corresponding to the liquid crystal conversion layer  201  and are in the liquid crystal layer  200  and the liquid crystal units (such as A 2 , A 4  and the like) which are not corresponding to the liquid crystal conversion layer  201  and are in the liquid crystal layer  200  is basically or slightly greater than 1:1. As shown in  FIG. 34 , the liquid crystal units  2011  of the liquid crystal conversion layer  201  are spaced apart in columns, or may be spaced apart in other ways, which is not limited in this embodiment. In addition, in order to facilitate showing a positional relationship between the liquid crystal layer  200  and the liquid crystal conversion layer  201 , there is a gap between the liquid crystal layer  200  and the liquid crystal conversion layer  201  in  FIG. 33  and  FIG. 34 ; and those skilled in the art can understand that in practical application, for example, the liquid crystal layer  200  and the liquid crystal conversion layer  201  are completely bonded, and there is for example no gap therebetween. 
     Based on the above embodiment, referring to  FIG. 35 , the passive light-emitting image source further includes: a blocking layer  202 ; the blocking layer  202  is arranged on the side, faces away from the light sources  104 , of the liquid crystal layer  200 , and a distance between the blocking layer  202  and the liquid crystal layer  200  is a preset distance; the blocking layer  202  includes a plurality of blocking units that are spaced apart. 
     In  FIG. 35 , it is illustrated by taking a case that the liquid crystal layer  200  includes 6 liquid crystal units and the blocking layer  202  includes 5 blocking units as an example. As shown in  FIG. 35 , since there is a gap between the blocking layer  202  and the liquid crystal layer  200 , and since the blocking layer  202  can block light, light emitted by part of the liquid crystal units (R 1 , R 2 , R 3 ) in the liquid crystal layer  200  cannot reach the position of the left eye, so that the left eye LE can only view light emitted by pixel units L 1 , L 2 , and L 3 ; similarly, the right eye RE can only see light emitted by pixel units R 1 , R 2  and R 3 . Therefore, the blocking layer  202  can divide the liquid crystal units of the liquid crystal layer  200  into two parts, and the light emitted by part of liquid crystal units such as liquid crystal units L 1 , L 2  and L 3  can only reach the position of the left eye; while the light emitted by other liquid crystal units such as liquid crystal units R 1 , R 2  and R 3  can only reach the right eye. During display imaging, two types of images with parallax are displayed by different liquid crystal units in the liquid crystal layer  200 , so that there is parallax between an image viewed by the left eye and an image viewed by the right eye, thereby implementing 3D imaging. 
     For example, the size of each blocking unit  2021  in the blocking layer  202  and a position between the blocking units  2021  are designed after precise calculation, and then imaging can be performed at a predetermined position. In this way, the observer can view the 3D image without wearing special glasses, but the observer can view a relatively good 3D imaging effect at the predetermined position. 
     Optionally, the blocking unit  2021  of the blocking layer  202  is a liquid crystal. When working, the liquid crystal of the blocking layer  202  can allow light to pass through; when not working, the liquid crystal is equivalent to an opaque baffle, which can also achieve an effect of blocking the light by the blocking units. For example, when the observer is to view the 2D image, the liquid crystal of the blocking layer  202  works, and in this case, the liquid crystal layer  200  normally displays the 2D image. When the observer is to view the 3D image, the liquid crystal of the blocking layer  202  does not work, and different pixels of the liquid crystal layer  200  display images with parallax, so that the observer can view the 3D image at a specific position. 
     For example, the blocking layer  202  may be a complete liquid crystal, that is, the blocking layer  202  is an integral-type liquid crystal; and the blocking layer  202  is not divided into multiple blocking units in structure, and a plurality of blocking units that are spaced apart can be formed by controlling the working states of the liquid crystals of the blocking layer  202 ; that is, it can be determined which part of the blocking layer is to block the light (equivalent to the blocking units) and which part allows the light to pass through, and in this case, the function of not blocking the light can also be achieved. In addition, the working states of the liquid crystals in the blocking layer  202  can be controlled in combination with the position of the human eye, so that the blocking layer  202  can follow the positions of the human eyes to perform an adjustment in real time for which liquid crystal units do not work (that is, blocking the light), and which liquid crystal units allow the light to pass through (that is, there is no blocking unit), so that the observer can view the 3D image at any position, which solves the problem that the observer can only view the 3D image at the specific position after the blocking units of the blocking layer  202  are fixed. 
     Based on the above embodiments, referring to  FIG. 36 , the passive light-emitting image source further includes: a cylindrical lens layer  203 , and the lenticular lens layer  203  is arranged on the side of the liquid crystal layer  200  away from the light sources  104 . The cylindrical lens layer  203  includes a plurality of cylindrical lenses that are vertically arranged, and each cylindrical lens covers at least two different columns of liquid crystal units  2001  of the liquid crystal layer  200 . The cylindrical lenses are configured to transmit light emitted by a row of liquid crystal units to a first position, and transmit light emitted by another column of liquid crystal units to a second position. 
     In this embodiment, light emitted by different columns of liquid crystal units are refracted to different positions by the cylindrical lenses, so that 3D imaging can be implemented. For example, referring to  FIG. 36 ,  FIG. 36  is a top view, and in a perpendicular direction, the liquid crystal layer  200  includes 12 columns of liquid crystals, and each column of liquid crystals includes one or more liquid crystal units; in order to simplify the description, this embodiment takes each column including one liquid crystal unit as an example. The cylindrical lens layer  203  includes a plurality of cylindrical lenses  2031 . For example, the cylindrical lens layer  203  includes 6 cylindrical lenses, and each cylindrical lens covers two columns of liquid crystal units. As shown in  FIG. 36 , the uppermost cylindrical lens covers the liquid crystal units R 1  and L 1 . Based on a refraction characteristic of a cylindrical lens, by setting a curved surface of the cylindrical lens, light emitted by a row of liquid crystal units can be transmitted to the first position after passing through the cylindrical lens, and for example, light emitted by the liquid crystal unit R 1  are transmitted to the position of the right eye; and light emitted by another column of liquid crystal units are transmitted to the second position after passing through the cylindrical lens, and for example, the light emitted by the liquid crystal unit L 1  are transmitted to the position of the left eye LE. By accurately setting the shape of the cylindrical lens, the light emitted by part of the liquid crystal units can be transmitted to a certain position, and light emitted by the other part of the liquid crystal units are transmitted to another position. That is, as shown in  FIG. 36 , light emitted by the liquid crystal units R 1 , R 2 , R 3 , R 4 , R 5 , R 6  and the like can be concentrated to the position of the right eye RE, and light emitted by the liquid crystal units L 1 , L 2 , L 3 , L 4 , L 5 , L 6  and the like can be concentrated to the position of the left eye, and then the observer can view the 3D image at the specific position when different liquid crystal units of the liquid crystal layer  200  display images with parallax. 
     In the solution provided by an embodiment of the present disclosure, light from different positions are concentrated to the same position by a direction controller element, which can improve the brightness of the light; and the light are diffused by a diffuser element, and thus, a light spot with a preset shape can be formed, which facilitates subsequent imaging within a light spot range, so that an imaging range can be expanded while the brightness of the light is improved. 
     In the embodiments of the present disclosure, diffusing means that light in a light beam diverge all around, and chief light (optical axis, or light axis) of the light beam passing through the diffuser element may be unchanged or changed. For example, in some embodiments, the light beam may be diffused into two light beams after passing through the diffuser element, and optical axes of the two light beams are different from chief light of a light beam incident upon the diffuser element. The diffuser element is configured to diffuse the light beam. The area of the cross section of the light beam incident upon the diffuser element is smaller than the area of the cross sections of the light beams after passing through the diffuser element. For example, in the embodiments of the present disclosure, the “chief light” refers to a centerline of the light beam, and may refer to a main propagation direction of light. 
     For example, the above embodiments of the present disclosure respectively provide a head-up display system, a light control apparatus, and a passive light-emitting image source, however, the embodiments of the present disclosure are not limited thereto. For example, the light control apparatus and the passive light-emitting image source in the above embodiments can be applied to the head-up display system in the above embodiments. For example, the light control apparatus in the embodiment described in  FIG. 22  or  FIG. 23  can replace parts in addition to the light sources and the reflective device for displaying in the head-up display system in any of the above embodiments; or as shown in  FIG. 22  or  FIG. 23 , the passive light-emitting image source in the above embodiments can replace parts in addition to the reflective device for displaying in any of the above embodiments. 
     Based on the above embodiments, the present disclosure further provides the following technical solutions. 
     (1) A light control apparatus is provided, the light control apparatus includes: the diffuser element and the direction controller element; 
     the direction controller elements is configured to concentrate light emitted by light sources at different positions; and 
     the diffuser element is arranged on a side of the direction controller element away from the light sources, and the diffuser element is configured such that light exit from the direction controller element is diffused by the diffuser element to form a light spot. 
     (2) In the light control apparatus according to (1), the direction controller element includes the collimator element; 
     the collimator element is configured to adjust an exit direction of light to be at an angle within a preset angle range, and emit the adjusted light to the diffuser element. 
     (3) In the light control apparatus according to (2), the collimator element includes a collimating lens or collimating film; and the collimating lens includes one or more selected from the group consisting of a convex lens, a concave lens, a Fresnel lens, or a combination thereof. 
     (4) In the light control apparatus according to (3), a distance between the collimator element and a position of a light source is equal to a focal length of the collimator element. 
     (5) In the light control apparatus according to (1), there are a plurality of direction controller elements, and different direction controller elements are arranged at different positions, and are configured to adjust exit directions of light emitted by the light sources at different positions, and the exit directions of the light emitted by the light sources at different positions all point to a same preset position. 
     (6) In the light control apparatus according to (1), the direction controller element further includes the light concentrator element; the light concentrator element is arranged between the light sources and the diffuser element, and the light concentrator element is configured to concentrate the light emitted by different light sources to a same preset position. 
     (7) In the light control apparatus according to (1), the direction controller element further includes the reflecting element; the reflecting element includes the lamp cup; the lamp cup is a hollow housing surrounded by the reflective surface, and the direction of the port of the lamp cup faces the diffuser element; a tail end, which is away from the port, of the lamp cup is used for arranging the light source. 
     (8) In the light control apparatus according to (7), the direction controller element further includes: the collimator element; the collimator element is arranged inside the lamp cup, and the size of the collimator element is smaller than the size of the port of the lamp cup; the collimator element is configured to collimate part of light emitted by the light sources in the lamp cup and then transmit the collimated light to the diffuser element. 
     (9) In the light control apparatus according to (1), the direction controller element further includes the reflecting element; the reflecting element includes the lamp cup with a solid center; the lamp cup with a solid center is the solid transparent component with the reflective surface, and a refractive index of the solid transparent component is greater than 1; the direction of the port of the lamp cup with a solid center faces the diffuser element; the end, away from the port, of the lamp cup with a solid center is configured to arrange the light source; light emitted by the light sources are totally reflected when being transmitted to the reflective surface. 
     (10) In the light control apparatus according to (9), the solid transparent component is provided with the cavity at the end away from the port of the lamp cup with a solid center, and the surface, close to the port of the lamp cup with a solid center, of the cavity is a convex surface; or the solid transparent component is provided with the slot in the central position of the end close to the port of the lamp cup with a solid center, and the bottom surface of the slot is a convex surface. 
     (11) Embodiments of the present disclosure further provide the passive light-emitting image source, which includes the light source, the liquid crystal layer, and the light control apparatus according to any one of (1)-(10); the light source and the liquid crystal layer are arranged on two side of the direction controller element of the light control apparatus. 
     (12) In the passive light-emitting image source according to (11), the light source includes the electroluminescence array consisting of one or more electroluminescent modules, and each electroluminescent module includes one or more electroluminescent devices; the light control apparatus includes one or more reflecting elements, and each electroluminescent module is correspondingly provided with at least one reflecting element. 
     (13) The passive light-emitting image source according to (11) includes a plurality of light control apparatuses; different light control apparatuses are configured to transmit the light emitted by the light source to different directions or regions. 
     (14) In the passive light-emitting image source according to (11), the liquid crystal layer includes the RGB filter; or the liquid crystal layer is the blue phase liquid crystal, and the light sources include a red light source, a green light source, and a blue light source; the light source, the green light source and the blue light source work periodically, and do not work simultaneously. 
     (15) In the passive light-emitting image source according to (11), the passive light-emitting image source further includes the liquid crystal conversion layer; the liquid crystal conversion layer is arranged on the side, away from the light sources, of the direction controller element; the liquid crystal conversion layer includes a plurality of liquid crystal units that are spaced apart, and one liquid crystal unit in the liquid crystal conversion layer corresponds to one liquid crystal unit in the liquid crystal layer; the liquid crystal units of the liquid crystal layer are configured to convert light in a first polarization direction into light in a second polarization direction, the liquid crystal units of the liquid crystal conversion layer are configured to convert the light in the second polarization direction into the light in the first polarization direction, and the first polarization direction is perpendicular to the second polarization direction. 
     (16) In the passive light-emitting image source according to (15), the total area of all the liquid crystal units in the liquid crystal conversion layer is larger than or equal to half of the total area of all the liquid crystal units in the liquid crystal layer. 
     (17) In the passive light-emitting image source according to (11), the passive light-emitting image source further includes: the blocking layer, the blocking layer is arranged on the side of the liquid crystal layer away from the light sources, and a preset distance is set between the blocking layer and the liquid crystal layer; the blocking layer includes a plurality of blocking units that are spaced apart. 
     (18) In the passive light-emitting image source according to (17), the blocking unit is a liquid crystal; or 
     the blocking layer is an integral-type liquid crystal, and by controlling the working state of the liquid crystal units of the integral-type liquid crystal, a plurality of blocking units that are spaced apart are formed. 
     (19) In the passive light-emitting image source according to (11), the passive light-emitting image source further including: a cylindrical lens layer, and the cylindrical lens layer is arranged on the side of the liquid crystal layer away from the light sources; the cylindrical lens layer includes a plurality of cylindrical lenses that are vertically arranged, and each cylindrical lens covers at least two different columns of liquid crystal units of the liquid crystal layer; the cylindrical lens is configured to transmit the light emitted by one column of liquid crystal units to a first position, and transmit the light emitted by another column of liquid crystal units to a second position. 
     (20) In the passive light-emitting image source according to (11), the light control apparatus further includes the light blocking element; the light blocking element is arranged on the side of the liquid crystal layer away from the light sources, and the light blocking element is configured to limit exit angles of the light emitted by the passive light-emitting image source. 
     (21) In the passive light-emitting image source according to any one of (11)-(20), the passive light-emitting image source further includes the reflection device; the reflection device is configured to reflect a light spot diffused by the light control apparatus, so that the light spot forms a virtual image outside the reflection device. 
     (22) Embodiment of the present disclosure further provide the head-up display system, which includes the passive light-emitting image source according to any one of (11)-(21). 
     The light control apparatus and the passive light-emitting image source provided by the embodiments of the present disclosure can be applied to the head-up display system provided by the embodiments of the present disclosure. In a case without conflict, different features in different embodiments can be combined with each other to obtain a new embodiment. 
     In the embodiments of the present disclosure, the liquid crystal layer may also be referred to as a liquid crystal unit, which includes a first substrate and a second substrate that are arranged oppositely, and a liquid crystal material layer that is sealed between the first substrate and the second substrate. For example, a first polarizing film and a second polarizing film are respectively arranged on the side of the first substrate away from the liquid crystal material layer and the side of the second substrate away from the liquid crystal material layer. 
     The above descriptions are only specific embodiments of the present disclosure, but the protection scope of the present disclosure is not limited thereto, those skilled in the art may make some improvements and modifications within the technical scope of the present disclosure, and the improvements and modifications should be within the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be determined by the protection scope of the claims.