CN114740622A

CN114740622A - Display device

Info

Publication number: CN114740622A
Application number: CN202210350773.7A
Authority: CN
Inventors: 杨晓东; 刘洋; 王建栋; 秦刚; 张珊珊; 李雄平
Original assignee: Shanghai Tianma Microelectronics Co Ltd
Current assignee: Shanghai Tianma Microelectronics Co Ltd
Priority date: 2022-04-02
Filing date: 2022-04-02
Publication date: 2022-07-12
Anticipated expiration: 2042-04-02
Also published as: CN114740622B

Abstract

The invention discloses a display device, which is characterized in that a light beam modulation unit is additionally arranged on a light path between an image source and a light beam output unit, the light beam modulation unit comprises a first area and a second area, the first area corresponds to an image to be displayed, light output by the image to be displayed is incident to the light beam modulation unit, the light enters human eyes after being reflected by the first area and the light beam output unit to ensure that a normal virtual image is formed, external light is incident to the light beam modulation unit after being transmitted by the light beam output unit, the second area of the light beam modulation unit filters the external light, the external light can be effectively prevented from entering the image source, the energy radiation of the external light to the image source is reduced, and the effect of prolonging the service life of the image source is achieved.

Description

Display device

Technical Field

The embodiment of the invention relates to the technical field of display, in particular to a display device.

Background

An augmented display head-up display (AR-HUD) generates a virtual image in front of a driver of a vehicle and provides the driver with various information by displaying information in the virtual image. Because the light path is reversible, sunlight reversely enters an image source of the head-up display screen, so that the sunlight radiation energy is too high, the service life of the image source is influenced, and the imaging effect of a virtual image is influenced.

Disclosure of Invention

The invention provides a display device, which is characterized in that a light beam modulation unit is arranged to reflect light emitted by an image source to reach human eyes to form a virtual image, so that the imaging effect of the virtual image is improved; meanwhile, incident natural light is filtered, so that radiation of external light to an image source is reduced, and the service life of the image source is prolonged.

The embodiment of the invention provides a display device, which comprises an image source, a light beam modulation unit and a light beam output unit;

the image source is used for outputting an image to be displayed;

the light beam modulation unit comprises a first area and a second area, the first area corresponds to the image to be displayed, light output by the image to be displayed is incident to the light beam modulation unit and enters human eyes after being reflected by the first area and the light beam output unit;

and the external light is transmitted by the light beam output unit and then enters the light beam modulation unit, and the light beam modulation unit is used for filtering the external light entering the second area.

According to the display device provided by the embodiment of the invention, the light beam modulation unit is additionally arranged on the light path between the image source and the light beam output unit and comprises the first area and the second area, the first area corresponds to an image to be displayed, light output by the image to be displayed is incident to the light beam modulation unit and enters human eyes after being reflected by the first area and the light beam output unit, so that a normal virtual image is ensured to be formed, external light is incident to the light beam modulation unit after being transmitted by the light beam output unit, and the second area of the light beam modulation unit filters the external light, so that the external light can be effectively prevented from entering the image source, the energy radiation of the external light to the image source is reduced, and the effect of prolonging the service life of the image source is achieved.

Drawings

Fig. 1 is a schematic structural diagram of a display device provided in the prior art;

fig. 2 is a schematic structural diagram of a display device according to an embodiment of the present invention;

FIG. 3 is a schematic diagram of a surface structure of a light beam modulation unit according to an embodiment of the present invention;

FIG. 4 is a schematic diagram of a surface structure of another light beam modulation unit provided in the embodiment of the present invention;

FIG. 5 is a schematic diagram of a surface structure of another light beam modulation unit according to an embodiment of the present invention;

FIG. 6 is a schematic structural diagram of another display device according to an embodiment of the present invention;

FIG. 7 is a schematic structural diagram of another display device according to an embodiment of the present invention;

FIG. 8 is a schematic structural diagram of another display device according to an embodiment of the present invention;

FIG. 9 is a schematic cross-sectional view along AA' of FIG. 3;

FIG. 10 is a schematic cross-sectional view taken along direction BB' in FIG. 3;

FIG. 11 is another schematic cross-sectional view taken along direction BB' in FIG. 3;

fig. 12 is a schematic structural diagram of another display device provided in an embodiment of the invention;

FIG. 13 is another schematic cross-sectional view taken along the direction CC' in FIG. 3;

FIG. 14 is a schematic diagram of another display device according to an embodiment of the present invention;

fig. 15 is a schematic structural diagram of another display device according to an embodiment of the present invention;

fig. 16 is a schematic structural diagram of another display device according to an embodiment of the present invention.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures.

Fig. 1 is a schematic structural diagram of a display device provided in the prior art. As shown in fig. 1, a display device 100 in the prior art includes an image source 10, a reflector 11 and a light beam output unit 12, in order to pursue a longer virtual image distance, an object plane of the light beam output unit 12 is generally closer to a focal plane, since a light path is reversible, sunlight is reversely concentrated into the image source 10 through the light beam output unit 12, and high-energy solar radiation affects the service life of the image source 10 and the visual imaging effect of virtual imaging.

Based on the technical problems, the inventor finds that the solar rays are reduced from entering the image source, the service life of the image source can be prolonged, and the visual imaging effect of virtual imaging is improved. Based on this, the inventors further studied the technical solutions of the embodiments of the present invention. Specifically, the embodiment of the invention provides a display device, which comprises an image source, a light beam modulation unit and a light beam output unit; the image source is used for outputting an image to be displayed; the light beam modulation unit comprises a first area and a second area, the first area corresponds to an image to be displayed, and light output by the image to be displayed enters the light beam modulation unit and enters human eyes after being reflected by the first area and the light beam output unit; the external light is transmitted by the light beam output unit and then enters the light beam modulation unit, and the light beam modulation unit is used for filtering the external light entering the second area.

By adopting the technical scheme, through additionally arranging the light beam modulation unit, the light beam modulation unit is arranged to comprise the first area and the second area, the first area corresponds to an image to be displayed, light output by the image to be displayed is incident to the light beam modulation unit, the light enters human eyes after being reflected by the first area and the light beam output unit, a normal virtual image is guaranteed to be formed, external light is incident to the light beam modulation unit after being transmitted by the light beam output unit, external light is filtered by the second area of the light beam modulation unit, the phenomenon that the external light enters an image source can be effectively reduced, energy radiation of the ambient light to the image source is reduced, and the effect of prolonging the service life of the image source is achieved.

The above is the core idea of the present invention, and the technical solution in the embodiment of the present invention will be clearly and completely described below with reference to the drawings in the embodiment of the present invention. All other embodiments, which can be obtained by a person skilled in the art based on the embodiments of the present invention without any creative work, belong to the protection scope of the present invention.

Fig. 2 is a schematic structural diagram of a display device according to an embodiment of the present invention; FIG. 3 is a schematic diagram of a surface structure of a light beam modulation unit according to an embodiment of the present invention; FIG. 4 is a schematic diagram of a surface structure of another light beam modulation unit provided in the embodiment of the present invention; fig. 5 is a schematic surface structure diagram of another optical beam modulation unit according to an embodiment of the present invention. As shown in fig. 2 to 5, the display device 200 according to the embodiment of the present invention includes an image source 20, a light beam modulating unit 21, and a light beam output unit 22; the image source 20 is used to output an image to be displayed; the light beam modulation unit 21 comprises a first area 211 and a second area 212, the first area 211 corresponds to an image to be displayed, a light beam L1 output by the image to be displayed is incident to the light beam modulation unit 21 and enters human eyes EE after being reflected by the first area 211 and the light beam output unit 22; the external light L2 is transmitted by the light beam output unit 22 and then enters the light beam modulation unit 21, and the light beam modulation unit 21 is configured to filter the external light entering the second area.

Specifically, the display device 200 provided by the embodiment of the present invention may be installed in a vehicle (e.g., an automobile), the display device 200 includes an image source 20, a light beam modulation unit 21, and a light beam output unit 22, the image source 20 includes a liquid crystal display panel, an organic light emitting display panel, or a projector, and may provide an image to be displayed, such as an AR-HUD image, and the content provided by the AR HUD may include instrument panel information, navigation information, lane indicator, construction indicator, accident indicator, and pedestrian detection indicator information. The light beam output unit 22 may be a vehicle windshield of a motorcycle, an automobile, an airplane, etc. for providing an AR-HUD image to a driver by adding a light beam modulation unit 21 in a light path between the light beam output units 22 at the image source 20. The light beam modulation unit 21 is configured to include a first region 211 and a second region 212, as shown in fig. 3, the first region 211 and the second region 212 may be arranged adjacently, and the first region 211 is configured to correspond to an image to be displayed of the image source 20, it should be noted that fig. 3 to 5 only respectively illustrate one possible configuration, and more configuration configurations are not listed here. The light beam L1 of the image to be displayed emitted by the image source 20 enters the human eye EE after being reflected by the first region 211 of the light beam modulation unit 21 and the light beam output unit 22 in sequence to form a virtual image, such as an AR-HUD image, thereby ensuring normal display of the virtual image. According to the principle that the light path is reversible, the external light L2 passes through the light beam output unit 22 and reaches the light beam modulation unit 21, and a part of the external light L2 is filtered by the second region 212 of the light beam output unit 22, for example, the external light L2 is filtered by adopting a specific wavelength absorption or scattering mode, so that the external light L2 can be effectively reduced from entering the image source 20, the energy radiation of the external light L2 to the image source 20 is reduced, and the service life of the image source 20 is prolonged.

To sum up, in the display device provided in the embodiment of the present invention, the light beam modulation unit is additionally disposed on the light path between the image source and the light beam output unit, and the light beam modulation unit includes a first region and a second region, where the first region corresponds to the image to be displayed, light output by the image to be displayed enters the light beam modulation unit, and enters the human eye EE after being reflected by the first region and the light beam output unit, so as to ensure that a normal virtual image is formed, external light enters the light beam modulation unit after being transmitted by the light beam output unit, and the second region of the light beam modulation unit filters external light, so that the external light entering the image source can be effectively reduced, energy radiation of the external light to the image source is reduced, and the effect of prolonging the service life of the image source is achieved.

FIG. 6 is a schematic structural diagram of another display device according to an embodiment of the present invention; FIG. 7 is a schematic structural diagram of another display device according to an embodiment of the present invention; fig. 8 is a schematic structural diagram of another display device according to an embodiment of the present invention. On the basis of the above embodiments, as shown in fig. 6 to 8, optionally, the display device 200 provided in the embodiment of the present invention further includes at least one reflection unit 23; the reflection unit 23 is disposed on the light path between the light beam modulation unit 21 and the light beam output unit 22, and a light beam L1 output by an image to be displayed enters the light beam modulation unit 21, and enters the human eye EE after being reflected by the first region 211, the reflection unit 23, and the light beam output unit 22 in sequence, as shown in fig. 6; or the reflection unit 23 is disposed on the light path between the image source 20 and the light beam modulation unit 21, and the light L1 output by the image to be displayed enters the reflection unit 23, and enters the human eye EE after being reflected by the reflection unit 23, the first region 211 and the light beam output unit 22 in sequence, as shown in fig. 7.

Specifically, as shown in fig. 6 to 8, the display device 200 further includes at least one reflection unit 23, and the reflection unit 23 may be a mirror coated with a high-reflection film for changing the propagation path of the light L1. As shown in fig. 6 and 7, a reflection unit 23 may be used, for example, the reflection unit 23 is disposed on the optical path between the light beam modulation unit 21 and the light beam output unit 22, and the light beam L1 output by the image to be displayed enters the human eye EE after sequentially passing through the first region 211 of the light beam modulation unit 21, the reflection unit 23 and the light beam output unit 22 for reflection, so as to form a virtual image, as shown in fig. 6; or the reflection unit 23 is disposed on the light path between the image source 20 and the light beam modulation unit 21, and the light beam L1 output by the image to be displayed enters the human eye EE after being reflected by the reflection unit 23, the first region 211 of the light beam modulation unit 21, and the light beam output unit 22 in sequence, so as to form a virtual image, as shown in fig. 7; or, two reflection units 23 are adopted, and the light L1 output by the image to be displayed enters the human eye EE after being reflected by the first reflection unit 231, the first region 211 of the light beam modulation unit 21, the second reflection unit 232, and the light beam output unit 22 in sequence, so as to form a virtual image, as shown in fig. 8. The volume of the display device 200 is adjusted by reasonably setting the number of the reflection units 23 and the light path positions of the image source 20 and the light beam modulation unit 21, so that the display device meets the installation environment requirements of the vehicle.

Optionally, and with continued reference to fig. 6-8, optionally, the reflecting unit 23 comprises a curved mirror. The curved reflector is favorable for converging light L1 output by an image to be displayed, so that the light energy utilization rate of the image source 20 is improved, and the imaging quality of the virtual image is improved.

FIG. 9 is a schematic cross-sectional view along AA' of FIG. 3; FIG. 10 is another schematic cross-sectional view taken along direction BB' in FIG. 3; fig. 11 is another schematic cross-sectional view in the direction BB' of fig. 3. On the basis of the above embodiments, as shown in fig. 2 and fig. 9 to fig. 11, optionally, the light beam modulation unit 21 includes a liquid crystal cell, and the liquid crystal cell includes an array substrate 213, an opposite substrate 214, and a liquid crystal layer 215 disposed between the array substrate 213 and the opposite substrate 214; when the display device 200 is in operation, the first region 211 of the liquid crystal cell is in the first state S1, as shown in FIG. 9, and the second region 212 of the liquid crystal cell is in the second state S2, as shown in FIG. 10, the liquid crystal cell includes a first state S1 and a second state S2.

Specifically, the light beam modulation unit 21 includes a liquid crystal cell, the liquid crystal cell includes an array substrate 213, an opposite substrate 214, and a liquid crystal layer 215 disposed between the array substrate 213 and the opposite substrate 214, the liquid crystal layer 215 is provided with regularly arranged liquid crystal molecules, and the arrangement of the liquid crystal molecules in the liquid crystal layer 215 is controlled by a region, so as to control the light transmittance of the liquid crystal cell. The liquid crystal molecules of the first region 211 of the liquid crystal cell are controlled to be in the first state S1, the first state S1 blocks light from transmitting through the liquid crystal layer 215, and the liquid crystal molecules of the second region 212 of the liquid crystal cell are controlled to be in the second state S2, the second state S2 allows light to transmit through the liquid crystal layer 215. When the display device 200 is in operation, the light L1 output by the image to be displayed enters the opposite substrate 214 side of the liquid crystal cell, and at the first region 211, the light L1 is reflected at the opposite substrate 214 and finally reaches the human eye EE to form a virtual image, as shown in fig. 9; at the second region 212, when the external light L2 enters the liquid crystal layer 215 after passing through the opposite substrate 214, it is absorbed or scattered by the liquid crystal layer 215, as shown in fig. 10 and 11.

With continued reference to fig. 9 and 11, based on the above embodiment, optionally, the first state is a reflective state and the second state S2 is a scattering state.

Specifically, as shown in fig. 9 to 10, the liquid crystal molecules of the liquid crystal layer 215 are controlled to be in the reflective state in the first state S1, that is, the light L1 is reflected at the first region 211 of the opposite substrate 214 and finally reaches the human eye EE to form a virtual image, as shown in fig. 9; the first state S1 is a scattering state, and the external light L2 is scattered and absorbed in the liquid crystal layer 215 after passing through the second region 212 of the opposite substrate 214 by the scattering effect of the liquid crystal molecules, and is difficult to reach the image source 20, so that damage to the image source 20 due to excessive energy radiation can be reduced.

Fig. 12 is a schematic structural diagram of another display device according to an embodiment of the present invention. On the basis of the above embodiments, as shown in fig. 9 to 11, optionally, the first state is a reflective state, and the second state S2 is a transparent state; the light beam modulation unit 21 further includes a light absorption layer 216, the light absorption layer 216 is disposed on a side of the liquid crystal cell away from the image source 20, and the light absorption layer 216 is used for absorbing the external light transmitted by the second region 212.

Specifically, as shown in fig. 9-10, the liquid crystal molecules of the liquid crystal layer 215 are controlled to be in the reflective state in the first state S1, i.e. the light ray L1 is reflected at the first region 211 of the opposite substrate 214 and finally reaches the human eye EE to form a virtual image, as shown in fig. 9; the second state S2 is a transparent state, i.e., the external light L2 can enter the liquid crystal layer 215 through the second region 212 of the opposite substrate 214. In order to block the external light L2 entering the liquid crystal layer 215, the light beam modulation unit 21 further includes a light absorption layer 216, and the light absorption layer 216 can absorb the external light L2, for example, a black absorption material is used. Optionally, the ambient light comprises sunlight. As shown in fig. 12, the external light L2 reaching the second region 212 sequentially passes through the opposite substrate 214, the liquid crystal layer 215 and the array substrate 213 and is absorbed by the light absorption layer 216, and the light absorption layer 216 disposed in the second region 212 can effectively reduce the external light L2 entering from the light beam output unit 22 and reflected by the light beam modulation unit 21 to reach the image source 20, thereby reducing the damage to the image source 20 caused by excessive energy radiation.

Fig. 13 is another schematic cross-sectional view taken along direction CC' in fig. 3. On the basis of the above embodiments, with continued reference to fig. 9-13, optionally, the liquid crystal cell further includes a pixel electrode 217 and a common electrode 218, the pixel electrode 217 is disposed on the array substrate 213, and the common electrode 218 is disposed on the array substrate 217 (not shown) or the opposite substrate 214; when the pixel electrode 217 is applied with the first voltage, the corresponding region is in the first state S1; when the pixel electrode 217 is applied with the second voltage, the corresponding region is in the second state S2.

Fig. 9 to 11 and 12 illustrate an example in which the pixel electrode 217 of the liquid crystal cell is disposed on the array substrate 213 and the common electrode 218 is disposed on the opposite substrate 214. Specifically, as shown in fig. 12, the array substrate 213 may further include an array substrate 2131, and a buffer layer 2132 and a driving circuit layer 40 sequentially disposed on one side of the array substrate 2131. The array substrate 2131 may be flexible or rigid, and for example, may be formed of any suitable insulating material having flexibility, which is used to block oxygen and moisture and prevent moisture or impurities from diffusing into the liquid crystal cell through the array substrate 2131. The buffer layer 2132 may cover the entire upper surface of the array substrate 2131, and the driving circuit layer 40 may include a plurality of Thin Film Transistors (TFTs) 30 (TFTs) arranged periodically and a pixel circuit formed by the TFTs 30, and the pixel circuit is configured to drive the liquid crystal in the liquid crystal layer 215 to deflect, reflect, transmit or scatter the incident light. The pixel circuit includes a plurality of metal wire layers, for example, as shown in fig. 12, the present embodiment is described by taking a bottom-gate thin film transistor 30 as an example, and the driving circuit layer 40 includes a gate layer 31 on a buffer layer 2132, a gate insulating layer 311 on the gate layer 31, an active layer 32 on the gate insulating layer 311, an interlayer insulating layer 312 on the active layer 32, a source electrode 33 and a drain electrode 34 on the interlayer insulating layer 312, the source electrode 33 and the drain electrode 34 being electrically connected (or bonded) to a source region and a drain region through contact holes, respectively, a planarization layer 313 on the source electrode 33 and the drain electrode 34 of the thin film transistor 30, a pixel electrode 217 on the planarization layer 313, and a pixel electrode insulating layer 314 on the pixel electrode 217. The gate insulating layer 311, the interlayer insulating layer 312, and the pixel electrode insulating layer 314 may be formed of an inorganic insulating layer such as silicon oxide or silicon nitride, the planarization layer 313 may be formed of an organic insulating layer, and further structures and preparation materials of the driving circuit layer 40 are not listed here. Only two thin film transistors 30 are shown, and the structure of more thin film transistors 30 is not shown here.

When a first voltage is applied to the pixel electrode 217, the liquid crystal molecules in the liquid crystal layer 215 in the corresponding first region 211 change in shape, so that the first region 211 is in the first state S1, the first state S1 is a reflective state, and a light ray L1 of an image to be displayed is reflected at the first region 211 of the opposite substrate 214 and finally reaches the human eye EE to form a virtual image; when the pixel electrode 217 is applied with the second voltage, the liquid crystal molecules in the liquid crystal layer 215 in the second region 212 are changed in morphology, so that the second region 212 is in the second state S2, and the second state S2 may be a scattering state (as shown in fig. 10) or a transparent state (as shown in fig. 11), so as to reduce the external light L2 from reaching the image source 20 after passing through the second region 212 of the opposite substrate 214, thereby reducing the radiation damage of the image source 20 caused by excessive energy radiation.

Fig. 14 is a schematic structural diagram of another display device according to an embodiment of the present invention. In addition to the above embodiments, referring to fig. 9, 13 and 14, the liquid crystal layer 215 includes cholesteric liquid crystal, and when the liquid crystal cell 21 is in the first state S1, the cholesteric liquid crystal forms a bragg reflection grating in a spiral shape; the light beam L1 emitted from the image source 20 is linearly polarized light, the display device 200 further includes a first quarter-wave plate 24, the first quarter-wave plate 24 is disposed on the light path between the image source 20 and the liquid crystal cell 21, and the first quarter-wave plate 24 is configured to modulate the linearly polarized light into circularly polarized light having the same rotation direction as that of the cholesteric liquid crystal.

Specifically, as shown in fig. 9-11 and 13, the liquid crystal layer 215 includes cholesteric liquid crystals, and the liquid crystal molecules are arranged in a flat shape in layers, the molecules in the layers are parallel to each other, the long axes of the molecules are parallel to the plane of the layers, and the long axes of the molecules in different layers have a slightly changed direction and are arranged in a spiral structure along the normal direction of the layers; the thread pitch of the cholesteric liquid crystal is about 300nm, is the same magnitude as the wavelength of visible light, and can change along with different external temperatures and electric field conditions, so that the external light can be modulated by applying different electric fields to adjust the thread pitch. The liquid crystal molecules of the liquid crystal cell 21 are adjusted to have a spiral cholesteric liquid crystal form a bragg reflection grating when the liquid crystal cell 21 is in the first state S1, and the cholesteric liquid crystal has a reflection effect on incident light. As shown in fig. 14, when the light beam L1 emitted from the image source 20 is linearly polarized light, the reflectivity of the cholesteric liquid crystal to the linearly polarized light is low, the linearly polarized light in the light path can be changed into circularly polarized light or elliptically polarized light by using the quarter wave plate, the first quarter wave plate 24 is additionally arranged on the light path between the image source 20 and the liquid crystal cell 21, and the first quarter wave plate 24 modulates the linearly polarized light L1 emitted from the image source 20 into circularly polarized light having the same rotation direction as that of the cholesteric liquid crystal, which is beneficial to improving the reflectivity of the cholesteric liquid crystal to the light beam L1, increasing the utilization rate of the light beam L2, and improving the imaging quality of virtual imaging.

Fig. 15 is a schematic structural diagram of another display device according to an embodiment of the present invention. On the basis of the above-described embodiment, as shown in fig. 15, the display device 200 further includes a second quarter-wave plate 25, the second quarter-wave plate 25 is disposed on the optical path between the liquid crystal cell 21 and the light beam output unit 22, and the second quarter-wave plate 25 is configured to modulate circularly polarized light into S-polarized light.

Specifically, when the light beam L1 emitted from the image source 20 is circularly polarized light, on the basis of fig. 14, the second quarter wave plate 25 is further added on the light path between the liquid crystal cell 21 and the light beam output unit 22, after the light beam L1 sequentially passes through 1/4 phase delay of the first quarter wave plate 24 and 1/4 phase delay of the second quarter wave plate 25, only the S-polarized light with the same polarization direction reaches the light beam output unit 22 and is reflected to the human eye EE, and the S-polarized light with the same polarization direction can improve the reflectivity of the light beam output unit 22 and improve the imaging quality of virtual imaging. Here, the S-polarized light is polarized light having a polarization vector direction parallel to the Z direction in fig. 15.

It should be noted that the display device 200 shown in fig. 2, 6-8 and 12 is still suitable when the light beam L1 emitted from the image source 20 is circularly polarized light or linearly polarized light.

Fig. 16 is a schematic structural diagram of another display device according to an embodiment of the present invention. In addition to the above embodiments, referring to fig. 9 and 16, the liquid crystal layer 215 includes cholesteric liquid crystal, and when the liquid crystal cell is in the first state S1, the cholesteric liquid crystal forms a spiral bragg reflection grating; the light beam L1 output by the image source 20 includes light beams of multiple colors, the display device 200 further includes a rotating unit 26, the rotating unit 26 is configured to drive the liquid crystal cell to rotate, so that the light beams of different colors meet 2d sin θ ═ n λ when entering the liquid crystal cell; where d denotes a thickness of the liquid crystal layer, θ denotes an incident angle of light, n denotes a refractive index of the liquid crystal, and λ denotes a wavelength of the corresponding light.

Specifically, the light beam L1 output by the image source 20 includes light rays of various colors, such as red light rays (R), green light rays (G), and blue light rays (B), and because the light wavelengths are different, the incident angles of the light rays emitted by the image source 20 on the surface of the liquid crystal cell are different, and the incident angle change of the light rays L1 emitted by the image source 20 reaching the liquid crystal cell can be realized by driving the liquid crystal cell to rotate by additionally arranging the rotating unit 26. Among them, the rotating unit 26 may be an angle rotating motor or the like. For example, the rotating unit 26 rotates the incident surface of the liquid crystal cell so that the incident angle of the incident light is θ₁When the image source 20 displays a red image, red light is reflected; when the incident angle of the incident light is theta₂When the green light is reflected, the image source 20 displays a green picture at this time; when the incident angle of the incident light is theta₃While reflecting blue light, the image source 20 displays a blue picture. When the HUD displays a color picture, the frequency of the picture displayed by the image source 20 is at least 120Hz, and the rotation frequency of the liquid crystal cell driven by the rotation unit 26 is consistent with the frequency of the picture displayed by the image source 20; if the HUD displays a monochrome picture, there is no need to rotate the liquid crystal cell and switch the color of light of the image source 20 to display the picture. By additionally arranging the rotating unit 26 to drive the liquid crystal box to rotate, color display or monochrome display at a user end can be realized.

On the basis of the above embodiment, with continued reference to fig. 13, the liquid crystal cell further includes a black light-shielding layer 219, where the black light-shielding layer 219 is used to shield a gap between different pixel electrodes 217.

Specifically, as shown in fig. 13, the liquid crystal cell further includes a black light-shielding layer 219(BM), where the liquid crystal molecules are disorderly turned at the boundary between the electrodes of the liquid crystal cell, and there may be light leakage, which results in luminance loss, and the gaps between different pixel electrodes 217 need to be shielded by BM, and the reflectivity of BM can be adjusted according to the luminance loss and the severity of stray light. For example, the black light-shielding layer 219 is provided on the counter substrate 214 to shield a gap between two adjacent pixel electrodes 217.

Based on the above embodiment, as shown in fig. 13 and fig. 16, optionally, the first region 211 includes a plurality of first sub-regions 2111, the second region 212 includes a plurality of second sub-regions 2121, the first sub-regions 2111 correspond to at least one pixel in the image source 20, and the second sub-regions 2121 correspond to at least one pixel in the image source 20.

Specifically, the light beam modulation unit may be partitioned according to actual needs, and may be at a pixel (pixel) level, the first region 211 includes a plurality of first sub-regions 2111, the size of the first sub-region 2111 corresponds to at least one pixel in the image source 20, for example, the size of the first sub-region 2111 is the same as the size of one pixel, the second region 212 includes a plurality of second sub-regions 2121, the second sub-region 2121 corresponds to at least one pixel in the image source 20, and taking one pixel in fig. 13 as an example, by corresponding to at least one pixel through the first sub-region 211 and the second sub-region 2121, reflection control of the light L1 emitted from the image source 20 is achieved, and absorption or scattering of the external light L2 is achieved, so that an imaging effect of virtual display imaging is improved.

In fig. 13, only the first region 211 includes a first sub-region 2111, the second region 212 includes a second sub-region 2121, and more structures are not shown here.

It is to be noted that the foregoing is only illustrative of the preferred embodiments of the present invention and the technical principles employed. Those skilled in the art will appreciate that the present invention is not limited to the particular embodiments described herein, and that various obvious changes, rearrangements and substitutions will now be apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A display device, comprising an image source, a light beam modulation unit and a light beam output unit;

the image source is used for outputting an image to be displayed;

2. The display device according to claim 1, further comprising at least one reflection unit;

the reflection unit is arranged on a light path between the light beam modulation unit and the light beam output unit, and light output by the image to be displayed enters the light beam modulation unit, is reflected by the first area, the reflection unit and the light beam output unit in sequence and then enters human eyes; or

The reflection unit is arranged on a light path between the image source and the light beam modulation unit, and light output by the image to be displayed enters the reflection unit, is reflected by the reflection unit, the first area and the light beam output unit in sequence and then enters human eyes.

3. The display device according to claim 2, wherein the reflection unit includes a curved mirror.

4. The display device according to claim 1, wherein the beam modulation unit comprises a liquid crystal cell including an array substrate, an opposite substrate, and a liquid crystal layer disposed between the array substrate and the opposite substrate;

the liquid crystal cell includes a first state and a second state, and when the display device is in operation, a first region of the liquid crystal cell is in the first state and a second region of the liquid crystal cell is in the second state.

5. The display device according to claim 4, wherein the first state is a reflective state and the second state is a transparent state;

the light beam modulation unit further comprises a light absorption layer, the light absorption layer is arranged on one side, far away from the image source, of the liquid crystal box, and the light absorption layer is used for absorbing external light transmitted by the second area.

6. A display device as claimed in claim 4, characterised in that the first state is a reflective state and the second state is a scattering state.

7. The display device according to claim 4, wherein the liquid crystal cell further comprises a pixel electrode disposed on the array substrate and a common electrode disposed on the array substrate or the counter substrate;

when the pixel electrode is loaded with a first voltage, the corresponding area is in the first state;

when the pixel electrode is loaded with a second voltage, the corresponding area is in the second state.

8. The display device according to claim 7, wherein the liquid crystal layer comprises cholesteric liquid crystal, and the cholesteric liquid crystal forms a Bragg reflection grating in a spiral shape when the liquid crystal cell is in the first state;

the display device comprises an image source, a liquid crystal box, a display device and a first quarter wave plate, wherein light beams emitted by the image source are linearly polarized light, the first quarter wave plate is arranged on a light path between the image source and the liquid crystal box, and the first quarter wave plate is used for modulating the linearly polarized light into circularly polarized light with the same rotating direction as that of the cholesteric liquid crystal.

9. The display device according to claim 8, further comprising a second quarter-wave plate disposed on an optical path between the liquid crystal cell and the light beam output unit, the second quarter-wave plate being configured to modulate the circularly polarized light into S-polarized light.

10. The display device according to claim 7, wherein the liquid crystal layer comprises cholesteric liquid crystal, and the cholesteric liquid crystal forms a Bragg reflection grating in a spiral shape when the liquid crystal cell is in the first state;

the display device further comprises a rotating unit, wherein the rotating unit is used for driving the liquid crystal box to rotate so that the light beams with different colors can meet the requirement that 2d sin theta is equal to n lambda when being incident to the liquid crystal box;

where d denotes a thickness of the liquid crystal layer, θ denotes an incident angle of light, n denotes a refractive index of liquid crystal, and λ denotes a wavelength of the corresponding light.

11. The device according to claim 7, wherein the liquid crystal cell further comprises a black light-shielding layer for shielding a gap between different pixel electrodes.

12. The display device of claim 1, wherein the first region comprises a plurality of first sub-regions, wherein the second region comprises a plurality of second sub-regions, wherein the first sub-regions correspond to at least one pixel in the image source, and wherein the second sub-regions correspond to at least one pixel in the image source.

13. The display device of claim 1, wherein the image source comprises a liquid crystal display panel, an organic light emitting display panel, or a projector.

14. The display device according to claim 1, wherein the light beam output unit includes a vehicle windshield.

15. The display device of claim 1, wherein the ambient light comprises sunlight.