CN111948811A

CN111948811A - Head-up display device

Info

Publication number: CN111948811A
Application number: CN202010215250.2A
Authority: CN
Inventors: 方涛; 徐俊峰; 吴慧军
Original assignee: Future Beijing Black Technology Co ltd
Current assignee: Future Beijing Black Technology Co ltd
Priority date: 2019-05-17
Filing date: 2020-03-24
Publication date: 2020-11-17
Also published as: CN212255879U; CN111948818A; CN111948817A; CN213092010U; CN111948810A; CN212989778U; CN212989777U

Abstract

The present invention provides a head-up display device, including: the light source comprises a light source, a collimation element, a light characteristic conversion element, a first transflective element, a retroreflective element, an image display layer and a second transflective element, wherein light rays which are emitted by the light source and comprise a first polarization characteristic and a second polarization characteristic are incident to the collimation element, are converted into light rays comprising the first polarization characteristic after passing through the light characteristic conversion element, the retroreflective element and the first transflective element, and then form image light rays through the image display layer, and the second transflective element reflects the image light rays to a preset position. The head-up display device provided by the embodiment of the invention can improve the utilization rate of light, and can emit high-brightness light by using a low-power light source so as to form a high-brightness image.

Description

Head-up display device

Technical Field

The invention relates to the technical field of optical imaging, in particular to a head-up display device.

Background

The head-up display (HUD) technology can avoid the driver to look at the distraction that the panel board leads to in driving process head-down, makes the driver can look over the image in sight range, improves driving safety factor, also can bring better driving experience simultaneously.

The head-up display usually projects an image onto a vehicle windshield or an imaging window, and therefore the head-up display requires high display brightness so that the driver can clearly see the content of the HUD display. Although the imaging brightness can be improved by improving the power of the HUD light source, the problems of high power consumption and large heat productivity of the light source are correspondingly brought, the power consumption is increased, and the heat dissipation requirement of the equipment is improved. Therefore, there is a need for a HUD design that can improve the utilization efficiency of the light emitted from the light source under the condition that the light source emits the same power.

Disclosure of Invention

To solve the above problems, an embodiment of the present invention provides a head-up display device, including:

a light source emitting light and incident to a collimating element; the light emitted by the light source comprises a first polarization characteristic and a second polarization characteristic;

the collimation element adjusts the emergent direction of the light rays emitted by the light source to be within a preset angle range;

a light characteristic conversion element that converts a characteristic of light passing through the light characteristic conversion element, and that allows light to pass through in both directions; the light rays with the second polarization characteristic are converted after even-numbered times of light rays with the second polarization characteristic penetrate through the optical characteristic conversion element, and the generated light rays comprise the light rays with the first polarization characteristic;

a first transflective element that transmits light of a first polarization characteristic and reflects light of a second polarization characteristic;

the surface of the retroreflection element facing to the light emergent direction is provided with a microstructure formed by a transparent material; the microstructure reflects light rays incident to the microstructure in the opposite direction of the incident direction after being reflected inside the microstructure;

an image display layer receiving the light emitted from the first transflective element and emitting image light, the image display layer being disposed on a side of the first transflective element away from the light source;

a second transflective element that reflects the image light to a predetermined position.

Optionally, the microstructure comprises a regular triangular cone shape, an isosceles triangular cone shape, a cubic cone shape or a spherical microstructure.

Optionally, the retroreflective element further includes a substrate, and the microstructure is a recessed structure formed on the substrate; the opening of the recessed structure faces the light characteristic conversion element.

Optionally, the microstructures are disposed between the light source and the first transflective element.

Optionally, the microstructures are disposed within a preset distance range around the light source as a center.

Optionally, the light source, the light characteristic conversion element, the first transflective element, and the image display layer are sequentially disposed.

Optionally, the collimating element adjusts the emitting direction of the light emitted by the light source to be parallel emitting.

Optionally, the collimating element is disposed between the light source and the optical characteristic conversion element, and collimates the light after being transmitted by the collimating element, and emits the light to the optical characteristic conversion element; the collimating element comprises a collimating lens or a collimating film.

Optionally, the collimating element includes a hollow shell with a reflective surface, light emitted from the light source is emitted out through the cavity of the hollow shell in the light emitting direction, and the light is reflected by the reflective surface of the collimating element, collimated, and emitted to the optical property conversion element.

Optionally, an opening of the hollow shell with the reflecting surface faces the light characteristic conversion element, and the light source is arranged at an end of the hollow shell far away from the opening; the hollow shell comprises a parabolic hollow shell with a reflective surface.

Optionally, the collimating element comprises a collimating lens and a hollow shell with a reflecting surface; the collimating lens is arranged between the light source and the optical characteristic conversion element, and is used for transmitting part of light rays emitted by the light source, collimating the light rays and emitting the light rays to the optical characteristic conversion element; and the reflecting surface is arranged around the light source, and the reflecting surface reflects and collimates the other part of light emitted by the light source and emits the light to the optical characteristic conversion element.

Optionally, the collimating lens is disposed inside the hollow casing with the reflecting surface, and the size of the collimating lens is smaller than the size of the opening of the casing.

Optionally, the collimating lens includes one or more of a convex lens, a concave lens, a fresnel lens, or a combination of the above lenses.

Optionally, the light with the first polarization characteristic is horizontally linearly polarized light, and the light with the second polarization characteristic is vertically linearly polarized light; or the light with the first polarization characteristic is vertically linearly polarized light, and the light with the second polarization characteristic is horizontally linearly polarized light.

Optionally, the optical characteristic conversion element includes a phase delay element.

Optionally, the phase delay element comprises an 1/4 wave plate.

Optionally, the first transflective element is one or more of a polymer film, an inorganic oxide film, or a photonic crystal.

Optionally, the image display layer includes a liquid crystal layer, a first polarizing plate and a second polarizing plate;

the polarization direction of the first polarizer is the same as that of the first polarization characteristic ray, and the polarization direction of the second polarizer is orthogonal to that of the first polarization characteristic ray.

Optionally, the light source further comprises a light gathering element; the light ray gathering element is arranged on one side of the first transflective element far away from the light characteristic conversion element; the light condensing element condenses light at a predetermined angle.

Optionally, the light condensing element includes one or more of a convex lens, a concave lens, a fresnel lens, or a combination of the above lenses.

Optionally, a dispersion element is also included; the diffusion element diffuses light into a light beam with a specific cross-sectional shape.

Optionally, the diffusing element is disposed on a side of the light concentrating element away from the first transflective element.

Optionally, the diffusing element is disposed between the first transflective element and the light collecting element.

Optionally, the dispersive element is a diffractive optical element.

Optionally, the light source further comprises a light blocking element; the light ray blocking element is arranged on one side, far away from the light source, of the image display layer and used for limiting the emergent angle of emergent light rays.

Optionally, the head-up display device includes at least two light sources; the number of the light sources is the same as that of the collimation elements, and the light sources and the collimation elements are in one-to-one correspondence;

optionally, the head-up display device includes at least two light sources; the number of the light sources is smaller than the number of the collimating elements, and the plurality of light sources correspond to one collimating element.

In the scheme provided by the embodiment of the invention, the light beam which is emitted by the light source and comprises the first polarization characteristic and the second polarization characteristic enters the collimation element, is converted into the light beam comprising the first polarization characteristic after passing through the light characteristic conversion element, the retro-reflection element and the first transflective element, then passes through the image display layer to form the image light beam, and the second transflective element reflects the image light beam to the preset position. The head-up display device provided by the embodiment of the invention can improve the utilization rate of light, and can emit high-brightness light by using a low-power light source so as to form a high-brightness image.

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

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

Fig. 1 is a schematic diagram illustrating a first structure of a head-up display device according to an embodiment of the invention;

fig. 2 is a schematic diagram illustrating a second structure of a head-up display device according to an embodiment of the invention;

fig. 3 is a schematic diagram illustrating a third structure of a head-up display device according to an embodiment of the invention;

FIG. 4a is a first schematic view of a microstructure of a retroreflective element provided in accordance with an embodiment of the present invention;

FIG. 4b is a second schematic diagram of the microstructure of the retroreflective elements provided by the embodiments of the present invention;

FIG. 4c is a third schematic view of the microstructure of the retroreflective elements provided by the embodiments of the present invention;

FIG. 5 is a fourth schematic diagram of a microstructure of a retroreflective element provided in accordance with an embodiment of the present invention;

fig. 6 is a schematic diagram illustrating a fourth structure of a head-up display device according to an embodiment of the invention;

fig. 7 is a schematic diagram illustrating a fifth structure of a head-up display device according to an embodiment of the invention;

fig. 8 is a diagram illustrating a sixth structure of a head-up display device according to an embodiment of the invention;

fig. 9 is a seventh schematic diagram of a head-up display device according to an embodiment of the invention;

fig. 10 is an eighth schematic diagram of a head-up display device according to an embodiment of the invention;

FIG. 11 is a schematic diagram illustrating a collimating element structure of a head-up display device according to an embodiment of the present invention;

fig. 12 is a schematic diagram illustrating a ninth structure of a head-up display device according to an embodiment of the invention;

fig. 13 is a diagram illustrating a tenth configuration of a head-up display device according to an embodiment of the invention;

fig. 14 is a schematic diagram illustrating an eleventh structure of a head-up display device according to an embodiment of the invention;

FIG. 15 is a first schematic diagram illustrating a diffusion element diffusing light of a head-up display device according to an embodiment of the present invention;

FIG. 16 is a second schematic diagram illustrating a diffusion element diffusing light of a head-up display device according to an embodiment of the present invention;

fig. 17 is a twelfth structural schematic diagram of the head-up display device according to the embodiment of the invention;

fig. 18 is a schematic structural view showing a hollow housing in the shape of a ridge in a head-up display device according to an embodiment of the present invention;

fig. 19 is a thirteenth structural schematic diagram of the head-up display device according to the embodiment of the invention;

fig. 20 is a schematic diagram illustrating a fourteenth structure of the head-up display device according to the embodiment of the invention.

Reference numerals: 100-light source, 200-collimation element, 300-light characteristic conversion element, 400-first transflective element, 500-retroreflective element, 600-image display layer, 700-second transflective element, 800-light gathering element, 900-dispersion element, 1100-light blocking element, 301-light characteristic conversion element surface, 302-light characteristic conversion element other surface, 201-hollow shell with reflecting surface, 202-collimation lens, 2011-hollow shell light outlet, 2012-hollow shell end, 2013-substrate, 501-microstructure and 502-substrate.

Detailed Description

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", and the like, indicate orientations and positional relationships based on those shown in the drawings, and are used only for convenience of description and simplicity of description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be considered as limiting the present invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.

In the description of the present invention and the accompanying drawings, the light rays shown in the drawings are for illustrating and explaining the operation principle of each element of the present invention, and do not represent that the light rays can reach an ideal state in practical application. In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

Referring to fig. 1, a head-up display device provided in this embodiment includes: a light source 100 emitting light and the light emitted from the light source 100 being incident on the collimating element 200; the light emitted by the light source 100 includes a first polarization characteristic and a second polarization characteristic; the collimating element 200, the collimating element 200 adjusts the emitting direction of the light emitted by the light source 100 to be within a preset angle range; an optical characteristic conversion element 300, the optical characteristic conversion element 300 converting the characteristic of the light passing through the optical characteristic conversion element 300, and the optical characteristic conversion element 300 allowing the light to pass through in both directions; the light rays with the second polarization characteristic are transmitted through the light characteristic conversion element 300 for even number of times and then converted to generate light rays with the first polarization characteristic; a first transflective element 400, the first transflective element 400 transmitting light of the first polarization characteristic and reflecting light of the second polarization characteristic; the surface of the retroreflective element 500 facing the light-emitting direction is provided with a microstructure formed by a transparent material; the microstructure reflects light rays incident to the microstructure in the direction opposite to the incident direction after being reflected inside the microstructure; an image display layer 600, the image display layer 600 receiving the light emitted from the first transflective element 400 and emitting image light, the image display layer 600 being disposed on a side of the first transflective element 400 away from the light source 100; a second transflective element 700, the second transflective element 700 reflecting the image light to a predetermined position.

Specifically, the preset position is an eye box (eyebox) position, and the eye box position is a position where the driver can observe the display content of the head-up display device with both eyes.

In particular, the second transflective element 700 may be a windshield or a transparent imaging window of a vehicle; the transparent imaging window may particularly be a light transparent plate, such as the imaging window of a C-HUD (Combiner-HUD). Further, the second transflective element 700 further includes a reflective film coated, attached or plated on a surface of the second transflective element, and the reflective film can efficiently reflect image light and efficiently transmit external environment light.

Specifically, the Light source 100 may be an Electroluminescent device, such as a Light Emitting Diode (LED), an incandescent Lamp, a laser, a quantum dot Light source, and the like, and specifically, for example, an Organic Light-Emitting Diode (OLED), a Mini LED (Mini LED), a Micro LED (Micro LED), a Cold Cathode Fluorescent Lamp (CCFL), an Electroluminescent Display (ELD), a Cold Light source (Cold LED Light, CLL), an Electroluminescent (EL), an electron Emission (FED), a tungsten halogen Lamp, a metal halide Lamp, and the like, which is not limited in this embodiment.

The collimating element 200 adjusts the emitting direction of the light emitted from the light source 100 to be within a predetermined angle range, specifically, the collimating element 200 adjusts the emitting direction of the light emitted from the light source 100 to be parallel emitting, as shown in fig. 1, the light emitted from the light source 100 has a large divergence angle, after passing through the collimating element 200, the collimating element 200 adjusts the emitting direction to be parallel emitting, and the predetermined angle can be considered as an included angle between a principal axis of the light (where the intensity of the light is maximum, such as a central light in fig. 1) and a place where the intensity of the light is small (such as a place 1/10 where the intensity of the light is minimum or maximum), or can be considered as an included angle between the principal axis of the light and a normal line of the. When the light is adjusted to exit in parallel, the preset angle is considered to be 0, that is, the exit direction of the light is parallel to the normal of the surface of the collimating element 200; the collimating element 200 can also adjust the light to be non-parallel within a predetermined angle range, such as ± 40 °, 35 °, 20 °, 10 °, or ± 1 ° with the normal of the surface of the collimating element 200, which is not limited in this embodiment.

Specifically, the light source 100 generating light, the light characteristic conversion element 300, the first transflective element 400, and the image display layer 600 are sequentially disposed, as shown in fig. 2. The light generated by the light source 100 is generally light with multiple polarization characteristics, such as natural light, and the light has multiple polarization characteristics, which can be understood as light that can be decomposed into at least two kinds of polarization characteristics. The natural light includes a plurality of polarization characteristics but does not have a unique polarization characteristic, for example, the natural light may include a first polarization characteristic and a second polarization characteristic, which are respectively denoted by a and B in fig. 2, and the light generated by the light source 100 includes the first polarization characteristic and the second polarization characteristic, which are denoted by AB. After the light ray AB passes through the collimating element 200, the light ray AB is adjusted to be a light ray AB exiting in parallel, and then passes through the optical characteristic conversion element 300, although the optical characteristic conversion element 300 can convert the characteristic of the light ray AB, because the light ray AB has a multi-polarization characteristic, the light ray AB still remains as a light ray with a multi-polarization characteristic after passing through the optical characteristic conversion element 300, that is, the light ray AB can still be regarded as the light ray AB after passing through the optical characteristic conversion element 300.

The multi-characteristic light ray AB comprises a first polarization characteristic and a second polarization characteristic, and the light ray AB can be understood to be capable of decomposing a light ray A and a light ray B; when the light ray AB with multiple characteristics is emitted to the first transflective element 400, due to the characteristics that the first transflective element 400 transmits the light ray with the first polarization characteristic and reflects the light ray with the second polarization characteristic, the light ray a transmits and reflects the light ray B, the light ray a transmitted from the first transflective element 400 is the light ray with the required characteristics, and then the light ray a can be emitted to the image display layer 600. Meanwhile, the optical characteristic conversion element 300 allows light to pass through in both directions, that is, the optical characteristic conversion element 300 allows light to enter from the surface 302 and to pass through from the surface 301, and also allows light to enter from the surface 301 and to pass through from the surface 302 in reverse; both

surfaces

301 and 302 of the light characteristic conversion element 300 can be used as light incident surfaces, i.e., surfaces closer to the light source 100 and receiving the light emitted from the light source 100, and the other surfaces can be used as light emitting surfaces, i.e., surfaces closer to the first transflective element 400 and emitting the light to the first transflective element 400, which can both perform the function of light characteristic conversion. After the light B reflected from the first transflective element 400 first passes through the light characteristic conversion element 300, the light characteristic conversion element 300 converts the light B having the second polarization characteristic into a light C having another polarization characteristic different from the second polarization characteristic. After the light C is reflected by the retro-reflective element 500, the light C is emitted again in the opposite direction of the incident light to the retro-reflective element 500, and can be transmitted through the light characteristic conversion element 300 again, and at this time, the light characteristic conversion element 300 converts the light C into a light D having another polarization characteristic. If the light ray D also has the first polarization characteristic, the light ray D having the first polarization characteristic may also transmit through the first transflective element 400.

The surface of the retro-reflective element 500 faces a light emitting direction, which specifically refers to a light emitting direction of the light source, i.e. a direction facing the optical characteristic conversion element 300. The surface of the retroreflective element 500 has a micro-structure formed of a transparent material, and the micro-structure reflects light incident to the micro-structure in a direction opposite to the incident direction after being reflected inside the micro-structure. That is, when the light ray AB emitted from the light source 100 reaches the retro-reflective element, the light ray AB passes through the other surface of the retro-reflective element 500 having the microstructure, the transparent material does not block the light ray from passing through, and the surface does not have a microstructure that can make the light ray reversely reflect; when the light ray AB passes through the retro-reflection element 500 to the optical characteristic conversion element 300 and then passes through the first transflective element 400, the light ray B with the second polarization characteristic is reflected on the first transflective element 400, the reflected light ray B passes through the optical characteristic conversion element 300 for the first time and then is converted into the light ray C, the light ray C reaches the surface of the retro-reflection element 500 with the microstructure, the shape of the microstructure is specially designed, the light ray C is reflected inside the microstructure, and finally is reflected in the opposite direction of the incident direction and passes through the optical characteristic conversion element 300 for the second time. The retro-reflecting element 500 is provided to make the reflected light similar to the exit path of the original light of the light source 100, and if the retro-reflecting element 500 is not provided or only a normal reflecting element is provided, the light C is not reflected in the opposite direction of the incident direction, and the reflected light C is excessively different from the original exit direction of the light source 100, and even if it reaches the light characteristic conversion element 300, it is finally difficult to use, and it does not contribute to the imaging light of the head-up display device. It is understood that in describing the conversion of the light characteristics, the reflected light C may or may not pass through the collimating element 200; the collimating element 200 does not change the polarization state of the light, so whether the light C passes through the collimating element 200 or not has no influence on the light characteristic conversion process, as long as it is ensured that the reflected light C passes through the retro-reflecting element 500 and is adjusted to exit in the opposite direction of the incident direction.

If the light ray D does not have the first polarization characteristic, the light ray D is reflected by the first transflective element 400 and then passes through the light characteristic converting element 300 for the third time, and then is reflected by the retro-reflective element 500 and then passes through the light characteristic converting element 300 for the fourth time; if the light passing through the light characteristic conversion element 300 for the fourth time has the first polarization characteristic, the light can pass through the first transflective element 400, otherwise, the light is continuously reflected by the first transflective element 400 until the light passing through the light characteristic conversion element 300 for even number of times has the first polarization characteristic. The first transflective element can reflect light with the second polarization characteristic and can also reflect light with other characteristics, for example, the light with the first polarization characteristic is linearly polarized light with a first polarization direction, the light with the second polarization characteristic can be linearly polarized light with a second polarization direction, and the first transflective element 400 can reflect the linearly polarized light with the second polarization direction and can also reflect circularly polarized light.

Optionally, as shown in fig. 3, the light source 100 may also be disposed between the light characteristic conversion element 300 and the first transflective element 400, and the principle of implementing light characteristic conversion is similar to that of the embodiment shown in fig. 1, and is not described herein again.

When the head-up display device is used, because the second transflective element 700, such as a windshield, has high reflectivity to S-polarized light and low reflectivity to P-polarized light, an image source of the head-up display is generally an LCD display emitting S-polarized light, and the LCD can only use polarized light in a specific polarization direction to realize display imaging. In the embodiment of the present invention, the collimating element 200, the light characteristic converting element 300, the first transflective element 400 and the retro-reflecting element 500 are disposed, so that the light ray with the second polarization characteristic reflected by the first transflective element 400 is converted into the light ray with the first polarization characteristic by the function of converting the transmitted light ray by the light characteristic converting element 300 and the function of returning the light ray by the retro-reflecting element 500, thereby allowing the converted light ray to pass through the first transflective element 400. That is, in the present embodiment, by providing the collimating element 200, the light characteristic converting element 300, the first transflective element 400 and the retro-reflecting element 500, the originally wasted light with the second polarization characteristic is converted into the light with the required first polarization characteristic and is transmitted out, so that the utilization rate and the light transmittance of the light emitted by the light source are improved, the light with high brightness can be transmitted out by the low-power light source, and the energy consumption of the light source can be reduced; meanwhile, due to the fact that the light transmittance is improved, the device cannot absorb a large amount of light energy, the heat productivity is small, and the requirement on heat dissipation is low. Therefore, the head-up display device provided by the embodiment of the invention can improve the light utilization rate, further improve the picture brightness of the head-up display, and meanwhile, the energy consumption of the head-up display device is smaller and the heat dissipation requirement is low.

It should be noted that, in the drawings of the present embodiment and the following embodiments, for convenience of describing the head-up display device, in the drawings of the present embodiment and the following embodiments, for convenience of describing the propagation condition or direction of the light rays, the size ratios between the light source 100, the collimating element 200, the light characteristic conversion element 300, the first transflective element 400, the retro-reflective element 500, the image display layer 600 and the second transflective element 700 are not completely consistent with those in practical use, the drawings are only for illustration and explanation, and do not represent the actual size or actual ratio of each element of the head-up display device according to the embodiments of the present invention, and each element in the present embodiment and the following drawings may be regarded as a partial enlarged schematic diagram for explaining the present invention. Meanwhile, in this embodiment and subsequent figures, a distance is formed between each element, for example, a distance is formed between each element in fig. 1 and fig. 2, but this is not intended to indicate that a space must exist between the elements, that is, the light characteristic conversion element 300 and the first transflective element 400 may be completely attached, or the space between the elements is small. The same applies to the arrangement of two other adjacent elements in the subsequent embodiments, unless a certain distance is required between the two elements. Meanwhile, for convenience of description, the reflection direction of the light ray C reflected by the retro-reflective element 500 in the drawings (e.g., fig. 1, fig. 2, etc.) is completely opposite to the incident direction; however, in practical applications, due to the limitation of the manufacturing process of the retroreflective element 500, the retroreflective element 500 may not completely retroreflect the light incident on the body in the opposite direction of the incident direction, and a small amount of light may not retroreflect in the opposite direction of the incident light.

In addition, the first transflective element 400 in this embodiment is used to "transmit the light with the first polarization characteristic and reflect the light with the second polarization characteristic", which means that the first transflective element 400 "can transmit the light with the first polarization characteristic and reflect the light with the second polarization characteristic", and does not mean that the first transflective element 400 "can only transmit the light with the first polarization characteristic and can only reflect the light with the second polarization characteristic", nor means that the light with the first polarization characteristic can completely transmit the first transflective element 400, and the light with the second polarization characteristic can completely reflect when passing through the first transflective element 400. Meanwhile, due to the limitation of the manufacturing process, even if the first transflective element 400 needs to completely transmit the light with the first polarization characteristic and completely reflect the light with the second polarization characteristic, there may be an error in practical applications, for example, a small amount of the light with the first polarization characteristic may be reflected by the first transflective element 400, and a small amount of the light with the second polarization characteristic may also be transmitted through the first transflective element 400.

It is understood that, in this embodiment, the light generated by converting the light with the second polarization characteristic after passing through the light characteristic conversion element 300 an even number of times includes the light with the first polarization characteristic, and the even number of times means that the light emitted from the light source 100 is reflected by the first transflective element 400, and the light with the initial characteristic of the second polarization characteristic passes through the light characteristic conversion element 300 an even number of times, which is denoted as the first pass. After the light emitted from the light source 100 passes through the optical characteristic conversion element 300 for the first time, the light includes the first polarization characteristic and the second polarization characteristic, but not the light with the second polarization characteristic, so the light passes through the optical characteristic conversion element for the first time without counting the number of times. That is, for the light including the first polarization characteristic and the second polarization characteristic emitted from the light source, the light generated by the conversion by the light characteristic conversion element an odd number of times includes the light of the first polarization characteristic; for the light with the second polarization characteristic reflected by the first transflective element, the light generated by even-numbered conversion after passing through the light characteristic converting element 300 includes the light with the first polarization characteristic. As shown in fig. 2, the light ray B is reflected by the first transflective element 400 and includes a light ray with a second polarization characteristic, which can be regarded as an initial light ray, and the light ray B is converted into the light ray C by the light characteristic converting element 300, and is the first-time transmitted light characteristic converting element 300; when the light ray C is converted into the light ray D, although the light ray C and the light ray B are not necessarily the same light ray, since the light ray C is obtained from the light ray B, the process of generating the light ray D by the light ray C passing through the optical characteristic conversion element 300 is regarded as the light ray B passing through the optical characteristic conversion element 300 for the second time. Similarly, the light rays with the second polarization characteristic pass through the optical characteristic conversion element 300 for the fourth, sixth, and other even times similarly to the above process, and are not described herein again.

On the basis of the above embodiments of the present invention, the polarization state of the light with the first polarization characteristic is different from that of the light with the second polarization state, and the polarization state specifically may include linear polarization, elliptical polarization, circular polarization, and the like; in this embodiment, if the polarization directions of the two linear polarizations are different, the polarization states are also different; the included angles of the slow axes of the two elliptical polarizations are different, and the polarization states can also be considered to be different; the polarization states are different if the two circular polarizations are rotated in different directions (left-hand or right-hand). Specifically, the light with the first polarization characteristic is horizontally linearly polarized light, and the light with the second polarization characteristic is vertically linearly polarized light; or the light with the first polarization characteristic is vertical linear polarized light, and the light with the second polarization characteristic is horizontal linear polarized light; or the light with the first polarization characteristic is left-handed circularly polarized light, and the light with the second polarization characteristic is right-handed circularly polarized light; or the light with the first polarization characteristic is right-handed circularly polarized light, and the light with the second polarization characteristic is left-handed circularly polarized light; or the light with the first polarization characteristic is left-handed elliptical polarized light, and the light with the second polarization characteristic is right-handed elliptical polarized light; or the light with the first polarization characteristic is rightwise elliptically polarized light, and the light with the second polarization characteristic is leftwise elliptically polarized light.

On the basis of the above-described embodiment of the present invention, the optical characteristic conversion element 300 is a phase retardation element, and changes the polarization state of light by changing the phase of light. The optical characteristic conversion element 300 can convert light having a certain polarization state (light having the second polarization characteristic) which has passed through itself even number of times into light having another polarization state (light having the first polarization characteristic), thereby achieving high utilization of light. Specifically, the phase retardation element may be an 1/4 wave plate, and the linearly polarized light beam with the first polarization direction passes through the 1/4 wave plate twice and is converted into linearly polarized light beam with the second polarization direction; the phase retardation element can also be an 1/8 wave plate, a 1/16 wave plate and the like, and the linearly polarized light in the first polarization direction can be completely converted into the linearly polarized light in the second polarization direction after respectively passing through the phase retardation plate for 4 times, 8 times and more even times.

In a preferred embodiment of the present invention, the first transflective element 400 transmits linearly polarized light of a first polarization direction and reflects linearly polarized light of a second polarization direction, and the optical characteristic conversion element 300 is an 1/4 wave plate. Specifically, as shown in fig. 2, the natural light AB emitted by the light source 100 and having a certain divergence angle is adjusted into a parallel light beam AB by the collimating element 200, and the light beam AB is still natural light after being emitted in parallel; after passing through 1/4 wave plate, light ray AB of natural light is a collection of a large number of elliptically polarized light with various major and minor axis ratios, and is still natural light, i.e. light ray AB is still natural light. The natural light can be decomposed into a second linearly polarized light and a first linearly polarized light, when the light ray AB is incident on the first transflective element 400, the first linearly polarized light (i.e., the light ray a with the first polarization characteristic) can transmit through the first transflective element 400, and the second linearly polarized light (i.e., the light ray B with the second polarization characteristic) is reflected to the 1/4 wave plate, i.e., the light ray B is reflected to the 1/4 wave plate. Afterwards, the second linearly polarized light B is converted into circularly polarized light (i.e., light C) after passing through 1/4 wave plate, the light C of the circularly polarized light is reflected reversely by the retro-reflective element 500, and then passes through 1/4 wave plate again, the light C of the circularly polarized light is converted into the first linearly polarized light (i.e., light D), at this time, both the light D and the light a are the first linearly polarized light, that is, the light B of the second linearly polarized light can be converted into the first linearly polarized light after passing through 1/4 wave plate twice, so that the light D can also pass through the first transflective element 400. Under the condition of not considering other losses, the light emitted by the light source AB can be completely emitted in the form of the first linearly polarized light (including the light A and the light D), and the utilization rate of light emitted by the light source is greatly improved.

It should be noted that linearly polarized light is converted into elliptically polarized light after passing through the 1/4 wave plate, and when the included angle between the polarization direction of the linearly polarized light and the optical axis of the 1/4 wave plate is 45 ° or 135 °, the linearly polarized light is converted into standard circularly polarized light. For convenience of explanation, this embodiment will be described by taking an example in which linearly polarized light is transmitted through 1/4 wave plates and then converted into circularly polarized light.

On the basis of the above embodiments of the present invention, the surface of the retro-reflective element 500 facing the light-emitting direction has a micro structure 501 made of a transparent material, the micro structure 501 reflects the light incident to the micro structure 501 in the inside of the micro structure and then reflects the light in the opposite direction of the incident direction, the micro structure includes a regular triangular cone shape, an isosceles triangular cone shape, a cubic cone shape or a spherical shape, specifically, the micro structure is a solid transparent member, the solid transparent member has a refractive index greater than 1, the light C is incident to the micro structure and then refracted to enter the solid transparent member, the light C is totally reflected on the inner surface of the solid transparent member, and finally the emergent direction of the light C is opposite to the incident direction of the light C, as shown in fig. 4a and 4b, schematic diagrams of the transparent solid members in the triangular cone shape and the cubic cone shape respectively reflecting the incident light C are shown, and after the light, after three times of total reflection on the inner surface, the final emergent direction is opposite to the incident direction; as shown in fig. 4C, fig. 4C is a schematic diagram of a process in which the spherical solid transparent member reflects light C in a reverse direction, the light C is reflected once in the spherical solid transparent member and then exits, in particular, a high-reflection coating needs to be disposed at an interface where the spherical solid transparent member reflects, the light C is refracted from the upper surface of the spherical solid transparent member 501 and then emitted to the high-reflection coating, and is reflected and then emitted back to the upper surface of the spherical solid transparent member 501, and the light C is refracted again and then exits in a direction opposite to the incident direction. It will be appreciated by those skilled in the art that any transparent microstructure that can perform a retroreflective function can be used as an embodiment of the retroreflective element 500 in the embodiments of the present invention.

In another embodiment, as shown in fig. 5, the retroreflective element 500 further includes a substrate 502, the substrate 502 may be made of a transparent material, the microstructure 501 is a recessed structure formed on the substrate, an opening of the recessed structure faces the optical characteristic conversion element 300, the light C is reflected by an inner surface of the recess after entering the microstructure, and finally the emergent direction of the light C is opposite to the incident direction of the light C, that is, the retroreflective element 500 makes the light C incident on the retroreflective element 500 undergo total reflection or reflection by disposing the transparent microstructure, and finally emerges in the opposite direction of the incident direction. As shown in fig. 5, the light ray C is reflected three times on the inner surface of the triangular pyramid-shaped concave microstructure and then exits in the opposite direction of the incident direction; further, a high-reflection coating may be added on the internal reflection surface where reflection occurs to improve the reflectivity, but the microstructure added with the high-reflection coating may only be disposed around the light source 100 and may not cover the light source 100, and if the light source 100 is covered, the light emitted by the light source 100 may be affected because the transmittance of the high-reflection coating is very low.

It can be understood that, in the embodiment, the number of the microstructures is plural, and the distribution of the plurality of microstructures on the retroreflective element may be uniform, for example, an array of uniformly distributed microstructures is formed, and the uniformly distributed plurality of microstructures may have a better retroreflective effect; the distribution of the plurality of microstructures may also be non-uniform, and may be used for a specific purpose, which is not limited in this embodiment.

On the basis of the above embodiments of the present invention, the microstructure 501 is disposed between the light source 100 and the first transflective element 400, and more specifically, between the light source 100 and the optical characteristic converting element 300, as shown in fig. 2, the microstructure 501 neither blocks the light emitted from the light source 100, but also reflects the light C incident to the microstructure; the microstructures 501 may also be disposed within a predetermined distance around the center of the light source 100, where the predetermined distance is a smaller distance, such as within 5mm, 10mm, or 20mm around the center of the light source 100. It will be understood by those skilled in the art that the light source 100 is generally one or more light emitting elements disposed on a substrate, and therefore the microstructures 501 may be disposed on the periphery of the light emitting elements on the substrate, and not block the light emitted from the light source 100, but also reflect the light C incident to the microstructures in the reverse direction, as shown in fig. 6, and the microstructures are disposed on the periphery of the light source 100.

On the basis of the above embodiments of the present invention, the collimating element 200 may be disposed between the light source 100 and the light characteristic converting element 300, and collimate the light after transmitting through the collimating element, and emit the light to the light characteristic converting element 300, as shown in fig. 2; specifically, the collimating element 200 may be a collimating lens or a collimating film, which is illustrated in fig. 2 as a collimating lens. The collimating lens includes one or more of a convex lens, a fresnel lens, a combination of lenses (e.g., a combination of a convex lens and a concave lens, a combination of a fresnel lens and a concave lens, etc.). Specifically, the collimating element 200 may be a convex lens, and the light source 100 may be disposed at a focal length of the convex lens, that is, a distance between the convex lens and the light source is a focal length of the convex lens, so that light rays emitted by the light source 100 in different directions can be emitted in parallel after passing through the collimating element 200. Alternatively, the collimating element 200 may be a collimating Film, such as a BEF Film (Brightness Enhancement Film), for adjusting the outgoing direction of the light rays to a predetermined angular range, for example, to focus the light rays to an angular range of ± 35 ° from the normal of the collimating Film. The collimating lens 200 may cover all the light emitted from the light source 100, or may cover a part of the light emitted from the light source 100, which is not limited in this embodiment.

On the basis of the above embodiments of the present invention, the collimating element 200 may be a hollow shell 201 with a reflective surface, the light emitted from the light source 100 is emitted out in the light direction through the cavity of the hollow shell 201, and the light is reflected by the reflective surface of the collimating element 200, collimated, and emitted to the optical characteristic conversion element 300, as shown in fig. 7. Specifically, the opening 2011 of the hollow casing 201 with the light reflecting surface faces the light characteristic conversion element 300, and the light source 100 is disposed at the end 2012 of the hollow casing far from the opening 2011. Specifically, the light reflecting surface of the hollow casing 201 is disposed on the inner surface, the hollow casing 201 may be a parabolic hollow casing with the light reflecting surface, and the light source 100 may be disposed at the focus of the parabolic hollow casing. It can be understood by those skilled in the art that when the light source 100 is disposed at the focus of the parabolic housing 201, the light rays emitted from the light source 100 with larger angles will be reflected on the inner wall of the parabolic housing 201 and emitted in the form of parallel light, as shown by the two light rays with larger angles in fig. 7, that is, the light rays emitted from the light source 100 can also be emitted in parallel by the shape design of the hollow housing and the reflective surface of the inner wall. It will be appreciated that a parabolic hollow shell is a preferred embodiment, and that the hollow shell may be spherical, free-form, cylindrical, or other shapes. Further, the hollow shell 201 is placed at the end 2012 of the light source 100, a substrate 2013 may also be disposed, the light source 100 is disposed on the substrate, and the hollow shell 201 and the substrate 2013 may be integrally formed or separately disposed, which is not limited in this embodiment of the present invention. It will be appreciated that the hollow housing 201 is primarily reflective and collimating adjacent to the reflective surface of the light source 100, and thus the hollow housing 201 may also only retain a portion of the housing disposed around the light source, as shown in fig. 8.

On the basis of the above embodiments of the present invention, the collimating element 200 may be a collimating lens 202 and a hollow shell 201 with a reflective surface, the collimating lens 202 is disposed between the light source 100 and the optical characteristic conversion element 300, and transmits part of the light emitted from the light source 100 to the optical characteristic conversion element 300; the reflective surface of the hollow casing 201 is disposed around the light source 100, and reflects another part of the light emitted from the light source 100, and then collimates the reflected light, and emits the collimated light to the light characteristic conversion element 300, as shown in fig. 9 and 10. The light rays (indicated by dotted lines in the figure) with a small exit angle emitted from the light source 100 are adjusted to be parallel exiting light rays by the collimating lens 202, and the collimating lens 202 includes one or more of a convex lens, a fresnel lens, and a lens combination (e.g., a combination of a convex lens and a concave lens, a combination of a fresnel lens and a concave lens, etc.). Specifically, when the collimating lens 202 is a convex lens, the light source 100 can be disposed at a focal length of the convex lens, that is, a distance between the convex lens and the light source is a focal length of the convex lens, so that light rays emitted by the light source 100 in different directions can be emitted in parallel after passing through the collimating lens 202. Alternatively, the collimating element 200 may be a collimating Film, such as a BEF Film (Brightness Enhancement Film), for adjusting the outgoing direction of the light rays to a predetermined angular range, for example, to focus the light rays to an angular range of ± 35 ° from the normal of the collimating Film. Another part of the light rays (shown by a solid line in the figure) emitted by the light source 100 with a larger emergent angle is reflected by the reflective surface on the inner surface of the hollow shell 201, the hollow shell 201 may be a parabolic shell, the light source 100 may be disposed at the focus of the parabolic hollow shell, the light rays emitted by the light source 100 with a larger emergent angle are reflected on the inner wall of the parabolic shell 201 and emitted in the form of parallel light, as shown by two large-angle light rays in fig. 9 and 10, that is, the purpose of adjusting the large-angle light rays emitted by the light source 100 to be emitted in parallel is achieved through the shape design of the hollow shell and the reflective surface on the inner wall. That is, the light emitted from the light source 100 has a smaller emergent angle, the light at the central position is adjusted to be collimated light by the collimating lens 202, and the light with a large angle is collimated after being reflected by the hollow shell 201, so that the light emitted from the light source 100 can be adjusted to be parallel emergent light as much as possible. It will be appreciated that the hollow housing 201 is primarily reflective and collimating adjacent to the reflective surface of the light source 100, and thus the hollow housing 201 may also only retain a portion of the housing disposed around the light source, as shown in fig. 10.

Further, when the collimating element 200 is a collimating lens 202 and a hollow housing 201 with a reflecting surface, the collimating lens 202 is disposed inside the hollow housing 201 with a reflecting surface, and the size of the collimating lens 202 is smaller than the opening size of the housing 201. Specifically, the collimating lens 202 is disposed inside the hollow housing 201, and may be disposed at any position of the

openings

2011 and 2012 of the hollow housing, as shown in fig. 9, or disposed at a cavity inside the housing, or disposed at the opening 2011 of the housing 201, as shown in fig. 10, which is not limited in this embodiment of the present invention. The size of the collimating lens 202 is smaller than the size of the opening of the housing 201, and as shown in fig. 11 in particular, the size of the opening of the housing 201 is the size of the housing (as shown by the dotted line) of the cross section where the collimating lens 202 is located. More specifically, the included angle θ between the central ray of the light source 100 and the ray (shown by the dashed line) reaching the edge of the collimating lens 202 is less than or equal to 60 °, for example, θ may be 10 °, 20 °, 30 °, 40 °, 50 °, or 60 °.

Further, when the collimating element 200 includes a hollow shell with a reflective surface, the microstructures of the retro-reflecting element 500 are disposed around the light source 100, and besides being disposed on the substrate around the light source 100, they can also be disposed on the reflective surface of the hollow shell close to the light source 100, as shown in fig. 12 and 13, and the retro-reflecting element 500 can still perform a function of retro-reflecting the light C.

Based on the above embodiments of the present invention, the first transflective element 400 may be a polymer film, an inorganic oxide film, or a photonic crystal, and can selectively transmit and reflect polarized light. Specifically, the polymer Film includes a Reflective Polarizer Mirror (RPM) Film or a Dual Brightness Enhancement Film (DBEF), and the transmission of the first linearly polarized light and the reflection of the second linearly polarized light are achieved by the RPM Film or the DBEF; the inorganic oxide film is formed by stacking one or more of tantalum pentoxide, titanium dioxide, magnesium oxide, zinc oxide, zirconium oxide, silicon dioxide, magnesium fluoride, silicon nitride, silicon oxynitride and aluminum fluoride; the photonic crystal can be used for transmitting the light with the first polarization characteristic at a single incident angle, wherein the single incident angle refers to that the incident angle of the light is a specific angle or the incident angle is within a preset incident angle range, that is, only the light with the first polarization characteristic incident on the photonic crystal along a certain specific incident angle (for example, the light is perpendicularly incident on the surface of the photonic crystal or the like) or the incident angle range can be transmitted through the photonic crystal.

On the basis of the above-described embodiment of the present invention, the image display layer 600 includes the liquid crystal layer, the first polarizing plate having the same polarization direction as the first polarization characteristic ray, and the second polarizing plate having the polarization direction orthogonal to the first polarization characteristic ray. Specifically, the liquid crystal layer may be a common liquid crystal, such as a Twisted Nematic (TN) liquid crystal, a High Twisted Nematic (HTN) liquid crystal, a Super Twisted Nematic (STN) liquid crystal, a Formatted Super Twisted Nematic (FSTN) liquid crystal, a blue phase liquid crystal, and the like, and the light is converted into image light by passing through the image display layer, and the image is observed by the driver after being reflected by the second transflective element.

On the basis of the above-mentioned embodiment of the present invention, referring to fig. 14, the head-up display device further includes a light condensing element 800; the light condensing element 800 is disposed on a side of the first transflective element 400 away from the light characteristic converting element 300. The light condensing element 800 serves to condense light at a predetermined angle and to condense light in a predetermined range. By providing the light concentrating element 800, the light can be concentrated to a predetermined range, for example, the predetermined range is a point in fig. 14, and it can be understood by those skilled in the art that the predetermined range can also be a smaller area, which is not limited in this embodiment. It can be appreciated that when the second transflective element 700 is not present, the light converges to a predetermined range in which a complete image can be observed, and since the light converges to a small range, efficient use of the light is achieved, and thus the image brightness is high. When the second transflective element 700 is present, a high-brightness HUD image is observed by the driver at a predetermined position, i.e., a virtual image position of a predetermined range with respect to the second transflective element. The light condensing element 800 may be specifically a fresnel lens, a convex lens, or a lens combination (for example, a combination of a convex lens and a concave lens, a combination of a fresnel lens and a concave lens, etc.). For example, if the light condensing element 800 is a convex lens, the predetermined range is the focal position of the convex lens.

On the basis of the above-described embodiment of the present invention, in order to enlarge the imaging range and increase the area of the image observed by the observer, the head-up display device further includes a diffusing element 900, and the diffusing element 900 diffuses the light into a beam having a specific cross-sectional shape. As shown in fig. 15, the light beam passing through the dispersing element 900 is transformed into a light beam with a specific cross-section, which is illustrated as a rectangle in fig. 15, and the size and shape of the cross-section of the light beam are determined by the microstructure of the dispersing element 900, and the cross-section of the light beam includes, but is not limited to, a circle, an ellipse, a square or a rectangle, and the dispersing element 900 can also transform the light beam into at least two separate light beams with specific cross-section, which is illustrated as a light beam transformed into two light beams with a rectangular cross-section in fig. 16. The dispersive element 900 may particularly be a Diffractive Optical Elements (DOE), such as a Beam shaping sheet (Beam Shaper). The diffusion angle of the diffused light spots in the side view direction is 10 degrees, preferably 5 degrees; the dispersion angle in the front view direction is 50 degrees, preferably 30 degrees.

In particular, the diffusing element 900 may be located on the side of the light concentrating element 800 remote from the first transflective element 400, as shown in FIG. 17. The dashed rays in fig. 17 represent the light paths when no dispersing element 900 is provided, and the rays are finally converged to a small extent. After addding diffusion element 900, light diverges with certain dispersion angle, shows with solid line light in fig. 17, can see that light finally assembles in a great scope, just so can guarantee that new line display device has great visual scope, and the HUD image can all be observed to driver's both eyes in this scope, has further enlarged HUD's application range.

Specifically, the diffusing element 900 may also be located between the first transflective element 400 and the light collecting element 800, and the specific process is similar to that of the above embodiment and is not described again. The arrangement of a plurality of diffusion elements 900 makes the distribution of light more uniform, and for convenience of explanation, one diffusion element 900 is used as an example in the embodiments and the schematic drawings, and the number of diffusion elements 900 is not limited by the embodiments of the present invention.

On the basis of the above embodiments of the present invention, one light source 100 may be provided with one collimating element 200, or a plurality of light sources 100 may share one collimating element 200, as shown in fig. 1; when there are a plurality of light sources 100, the plurality of light sources 100 may be arranged in a matrix, such as 4 light sources arranged in a 2 x 2 matrix, sharing one collimating element 200, such as the plurality of light sources 100 sharing one collimating lens 202 or one hollow housing 201; in addition, the plurality of light sources 100 may be arranged in a row, and the plurality of light sources 100 may emit uniform light by special design. Referring specifically to fig. 18, the collimating element 200 may be a hollow housing 201, the hollow housing 201 is a housing in the shape of a roof ridge with an opening, and the light sources 100 are arranged in a row at an end 2012 of the housing in the roof ridge away from the opening 2011; the light emitted by the row of light sources 100 can be uniformly emitted along the opening direction through the housing in the shape of a ridge, and the collimating effect can be further increased by matching with the collimating lens 202, and at the moment, the collimating lens 202 can be a plano-convex cylindrical lens and can collimate the light emitted by the row of light sources 100.

On the basis of the above embodiments, referring to fig. 19, the head-up display device further includes a light blocking element 1100, the light blocking element 1100 is disposed on a side of the image display layer 600 away from the light source 100, and the light blocking element 1100 is used for limiting an exit angle of the image light. Specifically, the light blocking member 1100 includes a plurality of light blocking barriers having a predetermined height, and the light is physically blocked from being transmitted in some directions by forming a barrier array by the plurality of light blocking barriers having protrusions. By designing the height and width of the light blocking barrier, the angle at which the observer can see the light can be limited. As shown in fig. 19, light exiting the image display layer 600 is confined to an angle α by the light blocking member 1100, thereby forming an observable region; that is, eye-1 is located within the viewable area where the image light is visible, but eye-2 is located outside the viewable area such that eye-2 cannot see the image light. Further, the surface of the light blocking element 1100 further includes a frosted layer that can scatter external ambient light such as sunlight, so as to prevent the external ambient light from reflecting on the surface of the light blocking element 1100 to generate glare, thereby affecting normal driving. Those skilled in the art can understand that the embodiments corresponding to fig. 1 to 18 may include the light blocking element 1100, which is not described herein.

Fig. 20 is an overall view of the head-up display device with the addition of a light blocking member 1100, and the light source 100 and the light blocking member 1100 are only schematically shown for convenience of explanation. The light blocking element 1100 can prevent a driver from directly viewing the screen of the head-up display, the height direction of the light blocking barrier of the light blocking element 1100 faces the second transflective element 700, the light blocking barrier is represented by a small rectangle in fig. 20, when the head-up display works, a real image is formed on the surface of an image display layer, and a virtual image is also formed through the second transflective element 700, because the light blocking element 1100 is arranged, the eye-3 of the driver cannot see the real image on the screen of the head-up display, and the virtual image formed by the head-up display can only be seen through the second transflective element 700; namely, the screen of the head-up display cannot be directly observed from the position of the user, so that when the user drives the vehicle, the influence of brightness when the screen of the head-up display is imaged on the visual field of the user or dizziness caused to the user can be avoided, and the safety during driving can be improved.

According to the head-up display device provided by the embodiment of the invention, the light with the second polarization characteristic which needs to be filtered originally is converted into the light with the first polarization characteristic which is needed and transmitted out, so that the utilization rate and the light transmittance of the light emitted by the light source are improved, the light with high brightness can be transmitted out through the low-power light source, the subsequent high-brightness imaging is facilitated, and the energy consumption of the light source is reduced; simultaneously, because the luminousness improves, a large amount of light energy can not be absorbed to the device, and calorific capacity is less, and is lower to HUD's heat dissipation requirement.

The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and all the changes or substitutions should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A head-up display device, comprising:

2. The heads-up display device of claim 1 wherein the microstructures comprise regular triangular pyramid shaped, isosceles triangular pyramid shaped, cubic cone shaped, or spherical microstructures.

3. The heads-up display device of claim 1 wherein the retroreflective element further comprises a substrate, the microstructures being recessed structures formed in the substrate;

the opening of the recessed structure faces the light characteristic conversion element.

4. The heads-up display device of claim 1 wherein the microstructures are disposed between the light source and the first transflective element.

5. The device of claim 1, wherein the microstructures are disposed within a predetermined distance around the center of the light source.

6. The head-up display device according to claim 1, wherein the light source, the light characteristic conversion element, the first transflective element, and the image display layer are disposed in this order.

7. The device of claim 1, wherein the collimating element adjusts the emitting direction of the light emitted from the light source to be parallel.

8. The head-up display device of claim 7, wherein the collimating element is disposed between the light source and the light characteristic conversion element, collimates light after being transmitted through the collimating element, and emits the light to the light characteristic conversion element;

the collimating element comprises a collimating lens or a collimating film.

9. The head-up display device of claim 7, wherein the collimating element comprises a hollow housing with a reflective surface, the light emitted from the light source exits through a cavity of the hollow housing in the light-emitting direction, and the light is reflected by the reflective surface of the collimating element, collimated, and emitted to the light characteristic conversion element.

10. The head-up display device according to claim 9, wherein the opening of the hollow case with the reflective surface faces the light characteristic conversion element, and the light source is disposed at an end of the hollow case away from the opening;

the hollow shell comprises a parabolic hollow shell with a reflective surface.

11. The heads-up display device of claim 7 wherein the collimating element comprises a collimating lens and a hollow housing with a reflective surface;

the collimating lens is arranged between the light source and the optical characteristic conversion element, and is used for transmitting part of light rays emitted by the light source, collimating the light rays and emitting the light rays to the optical characteristic conversion element;

and the reflecting surface is arranged around the light source, and the reflecting surface reflects and collimates the other part of light emitted by the light source and emits the light to the optical characteristic conversion element.

12. The heads-up display device of claim 11 wherein the collimating lens is disposed inside the hollow housing with the reflective surface, and wherein the collimating lens has a size smaller than an opening size of the housing.

13. The heads-up display device of any one of claims 8, 11 or 12 wherein the collimating lens comprises one or more of a convex lens, a concave lens, a fresnel lens or a combination thereof.

14. The head-up display device according to claim 1, wherein the light with the first polarization characteristic is horizontally linearly polarized light, and the light with the second polarization characteristic is vertically linearly polarized light;

or the light with the first polarization characteristic is vertically linearly polarized light, and the light with the second polarization characteristic is horizontally linearly polarized light.

15. The head-up display device according to claim 14, wherein the optical characteristic conversion element comprises a phase delay element.

16. The heads-up display device of claim 15 wherein the phase retardation element comprises an 1/4 wave plate.

17. The head-up display device of claim 1, wherein the first transflective element is one or more of a polymer film, an inorganic oxide film, or a photonic crystal.

18. The head-up display device according to claim 1, wherein the image display layer includes a liquid crystal layer, a first polarizing plate, and a second polarizing plate;

19. The heads-up display device of claim 1 further comprising: a light condensing element;

the light ray gathering element is arranged on one side of the first transflective element far away from the light characteristic conversion element;

the light condensing element condenses light at a predetermined angle.

20. The heads-up display device of claim 19, wherein the light condensing element comprises one or more of a convex lens, a concave lens, a fresnel lens, or a combination thereof.

21. The heads-up display device of claim 19 further comprising: a dispersion element;

the diffusion element diffuses light into a light beam with a specific cross-sectional shape.

22. The heads-up display device of claim 21 wherein the dispersing element is disposed on a side of the light concentrating element remote from the first transflective element.

23. The heads-up display device of claim 21 wherein the dispersing element is disposed between the first transflective element and the light collecting element.

24. The heads-up display device of claim 21 wherein the diffusing element is a diffractive optical element.

25. The heads-up display device of claim 21 further comprising: a light blocking element;

the light ray blocking element is arranged on one side, far away from the light source, of the image display layer and used for limiting the emergent angle of emergent light rays.

26. The heads-up display device of claim 1, wherein the heads-up display device includes at least two of the light sources;

the number of the light sources is the same as that of the collimation elements, and the light sources and the collimation elements are in one-to-one correspondence.

27. The heads-up display device of claim 1, wherein the heads-up display device includes at least two of the light sources;

the number of the light sources is smaller than the number of the collimating elements, and the plurality of light sources correspond to one collimating element.