Diffusion screen, display device and vehicle

Abstract

The invention provides a diffusion screen which can be applied to a projection display device, such as a head-up display system. The diffusion screen provided by the invention can reduce reflection of incident light on the surface of the diffusion screen and increase transmission, so that when stray light enters the surface of the diffusion screen, the stray light reflected into an imaging light path can be reduced, and the purpose of improving the imaging quality of a display system is achieved. Specifically, the diffusion screen provided by the invention comprises a first surface, a first film system is arranged on the first surface, the first film system is used for reducing the reflectivity of incident light on the first film system, and the first film system comprises multiple layers of first films with different refractive indexes.

Description

Technical Field

[0001] The present application relates to the fields of display technology and intelligent automobile driving technology, and more specifically, to a diffusion screen, a display device and a vehicle. Background Art

[0002] Cars have become an indispensable means of transportation in people's daily lives. With the increase in the number of cars, the frequency of traffic accidents is also increasing. In order to improve driving safety, head up display (HUD), especially augmented reality head up display (AR-HUD) has become a hot research direction.

[0003] In the HUD system, in order to avoid glare caused by backflow of sunlight and prevent most stray light from entering the human eye, the direction of the vertical line in the diffuser is usually set to be about 15° with the direction of the main imaging light. However, the direction of the main imaging light emitted by the picture generation unit (PGU) is usually ≤15°, resulting in energy loss of the imaging light emitted from the diffuser. Currently, the general solution is to add a field lens (such as a cylindrical lens, etc.) to the system and use the field lens to adjust the angle of the light, such as Figure 2 As shown. However, due to the large size of the field lens and the risk of stray light on the surface, not only does it cause the clarity of the displayed image to deteriorate, but it also increases the size and glare risk of the HUD system, and further increases the design complexity of the HUD system. Therefore, how to reduce the glare risk of the HUD system without changing the optical path design of the HUD system is a problem that needs to be solved. Summary of the invention

[0004] The present application provides a diffusion screen, a display device and a vehicle. The diffusion screen provided in the present application can achieve directional matching between projection light and image light, and when used in a display device, can reduce the volume of the display device and improve the imaging quality of the display device.

[0005] In a first aspect, an embodiment of the present application provides a diffusion screen, which includes: a first surface, on which a first film system is disposed, the first film system including a plurality of first thin films with different refractive indices, the first film system being used to reduce the reflectivity of incident light on the first film system.

[0006] Based on the above scheme, the diffuser screen provided by the present application can reduce the reflectivity of the incident light incident on the first film system, so that more incident light is transmitted into the first film system. It can be understood that, for the incident light being image light, the first film system can ensure that more incident light is transmitted through the diffuser screen, thereby reducing the reflection loss of the image light on the diffuser screen. For the case where the incident light is stray light, the lower reflectivity can avoid the deterioration of the imaging quality caused by the reflection of stray light into the imaging light path. Therefore, when the diffuser screen of the present application is applied to a display system, it can ensure the imaging quality of the system, thereby improving the user experience.

[0007] In combination with the first aspect, in some implementations of the first aspect, the refractive index of the multilayer first film gradually decreases in a direction away from the first surface.

[0008] In combination with the first aspect, in some implementations of the first aspect, the diffusion screen further includes a second surface, the second surface is opposite to the first surface, and the first film system is disposed on the second surface.

[0009] By arranging the same first film system on the first surface and the second surface of the diffusion screen, the anti-reflection performance of the diffusion screen can be further improved. At the same time, arranging the same first film system can also simplify the process flow and reduce costs.

[0010] In combination with the first aspect, in some implementations of the first aspect, the refractive index of the multilayer first film gradually decreases along a direction away from the second surface.

[0011] In combination with the first aspect, in some implementations of the first aspect, the diffuser screen further includes a second surface, the second surface is opposite to the first surface, a second film system is disposed on the second surface of the diffuser screen, the second film system includes a plurality of second thin films with different refractive indices, and the second film system is used to reduce the reflectivity of incident light on the second film system.

[0012] The first film system and the second film system are different in at least one of the following:

[0013] The number of layers of the first film system and the second film system, the refractive index of at least one first film in the multilayer first film and the refractive index of at least one second film in the multilayer second film, the thickness of at least one first film in the multilayer first film and the thickness of at least one second film in the multilayer second film.

[0014] By arranging different film systems on the first surface and the second surface of the diffusion screen, the use scenarios of the diffusion screen can be increased, making the design of the diffusion screen more flexible.

[0015] In combination with the first aspect, in some implementations of the first aspect, the refractive index of the multilayer second film gradually decreases in a direction away from the second surface.

[0016] In combination with the first aspect, in certain implementations of the first aspect, at least one of the first film system and the second film system is an anti-reflection AR film.

[0017] In combination with the first aspect, in certain implementations of the first aspect, at least one of the first film system and the second film system includes a microstructure, and the microstructure is used to reduce the reflectivity of the incident light on the film system including the microstructure.

[0018] The imaging quality of the system can be further improved by further reducing the reflectivity of the first film surface and the second film surface through the microstructure.

[0019] In combination with the first aspect, in some implementations of the first aspect, the refractive index of the first film system is determined based on the refractive index of the diffuser screen and the target reflectivity of the incident light in the first film system.

[0020] In a second aspect, an embodiment of the present application provides a display device. The display device includes a projection module, a first reflective element, a second reflective element, and a diffuser screen as described in the first aspect and any possible implementation of the first aspect. The projection module is used to project image light onto the second surface of the diffuser screen; the diffuser screen is used to transmit the image light from the projection module from the first surface to the first reflective element, and generate a relay image on the first surface based on the image light from the projection module; the first reflective element is used to reflect the image light from the diffuser screen to the second reflective element; and the second reflective element is used to reflect the image light from the first reflective element to the human eye.

[0021] In combination with the second aspect, in some implementations of the second aspect, an angle between a normal line of the second surface and the image light incident on the second surface is greater than or equal to 15°.

[0022] Based on the above solution, the possibility of sunlight entering the imaging light path after reflection can be further reduced, thereby reducing the glare of the display system and achieving the purpose of improving user experience.

[0023] In a third aspect, an embodiment of the present application provides a vehicle. The vehicle includes the display device and windshield in the second aspect and any possible implementation of the second aspect. The second reflective element is used to reflect the image light from the first reflective element to the windshield; and the windshield is used to reflect the image light from the display device to the human eye.

[0024] In a fourth aspect, an embodiment of the present application provides a vehicle-mounted system, which includes the display device in the second aspect and any possible implementation of the second aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 A schematic diagram of an application scenario of the HUD device provided in an embodiment of the present application.

[0026] Figure 2 A schematic diagram of using a cylindrical lens to match the projection light and imaging light directions of a HUD system.

[0027] Figure 3 This is a schematic structural diagram of a first diffusion screen 300 provided in an embodiment of the present application.

[0028] Figure 4 This is a schematic structural diagram of a second diffusion screen 400 provided in an embodiment of the present application.

[0029] Figure 5 This is a schematic structural diagram of a third diffusion screen 500 provided in an embodiment of the present application.

[0030] Figure 6 This is a schematic structural diagram of a fourth diffusion screen 600 provided in an embodiment of the present application.

[0031] Figure 7 A schematic diagram of a display device 700 provided in an embodiment of the present application.

[0032] Figure 8 A possible structure of the projection module 701 provided in an embodiment of the present application.

[0033] Fig. 9 A possible structure of the projection module 701 in which the modulation module 712 is a DMD is provided for the embodiment of the present application.

[0034] Fig.10 A schematic diagram of an optical path 1000 of a display device 700 provided in an embodiment of the present application when applied to a vehicle.

[0035] Fig.11 A circuit diagram of a display device provided in an embodiment of the present application.

[0036] Fig.12 A schematic diagram of a possible functional framework of a vehicle provided in an embodiment of the present application. DETAILED DESCRIPTION

[0037] The technical solutions in the embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0038] In order to facilitate understanding of the embodiments of the present application, the following explanation is made.

[0039] First, the terms "first", "second", etc. and various numbers in the text descriptions or drawings of the embodiments of the present application shown below are only used for the convenience of description, and are not necessarily used to describe a specific order or sequence, and are not used to limit the scope of the embodiments of the present application. For example, to distinguish different surfaces or different film systems, etc.

[0040] Second, the terms "including" and "having" and any variations thereof in the embodiments of the present application shown below are intended to cover non-exclusive inclusions. For example, a process, method, system, product or apparatus comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or apparatuses.

[0041] Third, in the embodiments of the present application, words such as "exemplarily" or "for example" are used to indicate examples, illustrations or descriptions, and the embodiments or designs described as "exemplarily" or "for example" should not be interpreted as being more preferred or more advantageous than other embodiments or designs. The use of words such as "exemplarily" or "for example" is intended to present related concepts in a specific way for easy understanding.

[0042] Fourth, in the embodiment of the present application, image light refers to light carrying an image (or image information) and is used to generate an image.

[0043] Fifth, in the drawings of the present application, the thickness, size and shape of each optical element have been slightly exaggerated for the sake of convenience. Specifically, the shapes of the optical elements shown in the drawings are shown by way of example. For example, the shape of the curved mirror in the present application is not limited to the spherical or aspherical shapes shown in the drawings. Moreover, the drawings are only examples and are not drawn strictly to scale.

[0044] Sixth, unless otherwise defined, all terms (including technical terms and scientific terms) used in this application have the same meaning as commonly understood by a person of ordinary skill in the art to which this application belongs. It should also be understood that terms (such as terms defined in commonly used dictionaries) should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and will not be interpreted in an idealized or overly formal sense unless explicitly defined in this article.

[0045] Seventh, in the description of the embodiments of the present application, the orientation or position relationship indicated by the terms "on" and the like is defined relative to the orientation or position of the components schematically placed in the drawings. It should be understood that these directional terms are relative concepts. They are used for relative description and clarification, rather than indicating or implying that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. It may change accordingly according to the change in the orientation of the components placed in the drawings, and therefore cannot be understood as a limitation on the present application.

[0046] Eighth, the present application relates to a light trapping structure. The light trapping structure is an anti-reflection technology. The principle is to form a series of tiny grooves or columnar structures on the surface of the material. When light is incident on a medium with a light trapping structure, the propagation path of the light will be extended to increase the absorption of the light, so that the light will be reflected and refracted multiple times when it is reflected on the surface of the material, thereby reducing the intensity of the reflected light.

[0047] Ninth, the present application relates to an anti-reflection coating (AR), also known as an anti-reflection coating or an anti-reflection coating. It is formed by coating one or more layers of thin films on a substrate. These thin films are usually composed of alternating materials of high refractive index and low refractive index. Among them, the film layer with a high refractive index will cause the phase delay of the light wave, and the film layer with a low refractive index will cause the phase advance of the light wave. When light is incident on the surface of the substrate from the external medium, a part of the light wave will be reflected on the surface of the substrate, and the other part will be transmitted through the substrate and reflected again, thereby interfering with the reflected light on the surface. Therefore, by controlling the thickness and refractive index of each layer, the interference effect at the surface of the substrate is minimized, thereby achieving the purpose of anti-reflection and anti-transmission.

[0048] Figure 1 A schematic diagram of an application scenario of the HUD device provided in an embodiment of the present application. Figure 1 As shown, the HUD device is set on the car. The HUD device is used to project the vehicle's status information, external object indication information and navigation information into the driver's field of vision through the vehicle's windshield (also called windshield). The status information includes but is not limited to driving speed, mileage, fuel level, water temperature and headlight status. The external object indication information includes but is not limited to safe vehicle distance, surrounding obstacles and reversing images. Navigation information includes but is not limited to direction arrows, distance and driving time.

[0049] Among them, the virtual image corresponding to the navigation information and the indication information of the external object can be superimposed on the real environment outside the vehicle, so that the driver can obtain the visual effect of augmented reality, for example, it can be used for augmented reality (AR) navigation, adaptive cruise, lane departure warning, etc. Since the virtual image corresponding to the navigation information can be combined with the real scene, the HUD device is usually coordinated with the advanced driving assistant system (ADAS) system of the car. In order not to interfere with the road conditions, the virtual image corresponding to the instrument information is usually about 2 to 3 meters away from the human eye. In order to better integrate the virtual image corresponding to the navigation information with the real road surface, the virtual image corresponding to the navigation information is generally about 7 to 15 meters away from the human eye. Among them, the position where the virtual image of the navigation information is located is called the far focal plane, and the plane where the virtual image of the instrument information is located is called the near focal plane.

[0050] At present, the research focus of HUD equipment is mainly on avoiding sunlight backflow and reducing the volume. Among them, the main reason for sunlight backflow is that after the external sunlight enters the imaging system, white spots are generated on the surface of the diffuser screen. After the white spots are reflected on the surface of the diffuser screen, they re-enter the imaging light path and enter the human eye, causing screen glare. Therefore, in order to avoid glare caused by sunlight backflow and improve user experience, in HUD devices, the normal direction of the diffuser screen is usually set to not coincide with the main direction of the imaging light. For example, in common HUD devices using Liquid Crystal On Silicon (LCoS) as display chips and HUD devices using Digital Light Procession (DLP) as display chips, the normal direction of the diffuser screen is usually at an angle of 15° to 30° with the main direction of the imaging light, but the main direction of the image light projected by the display chip to the diffuser screen is usually less than or equal to 15°, resulting in the main direction of the image light incident on the diffuser screen not matching the design, causing energy loss and affecting the imaging quality. In order to ensure the display effect of the HUD device, the angle arrangement between the PGU and the diffuser, as well as the angle arrangement between the diffuser and the reflective element (used to reflect the image light into the human eye) must strictly comply with the design, resulting in limited spatial layout of the HUD device and difficulty in reducing the volume. In order to make up for this design defect of the HUD device, in some solutions, a field lens, such as a cylindrical lens, is introduced into the HUD device to correct the angle of the image light incident on the diffuser. The optical path diagram of this solution is shown in the figure below. Figure 2However, in this solution, since the cylindrical lens is thick and large in size, more space is required in the HUD device to accommodate the cylindrical lens, resulting in a larger HUD device. At the same time, the thick cylindrical lens will also affect the clarity of the image. In addition, the cylindrical lens will also increase the reflective surface of the system, resulting in stray light in the HUD device and increasing the probability of glare.

[0051] In order to avoid the many defects caused by the introduction of field lenses, the present application proposes a diffusion screen, which is based on an anti-reflection film system arranged on at least one surface, and can reduce the glare caused by sunlight backflowing into the display device and improve the display effect of the HUD. Compared with the solution of introducing a field lens in the HUD light path, the solution of the present application does not increase the volume of the display device and can avoid the deterioration of the display effect caused by the field lens.

[0052] Figure 3 This is a schematic diagram of the structure of the first diffusion screen 300 provided in the embodiment of the present application. Figure 3 As shown, the diffusion screen 300 includes a first surface 301, on which a first film system 302 is disposed. The first film system 302 includes N layers of first films with different refractive indices, namely Figure 3 The first film #1, the first film #2, ... the first film #N in the film system 302, wherein N is an integer greater than or equal to 2. The first film system 302 is used to reduce the reflectivity of the incident light on the first film system 302.

[0053] Optionally, the refractive index of the multilayer first thin films of the first film system 302 gradually decreases in a direction away from the first surface 301 .

[0054] Exemplarily, when N is equal to 5, the first film system 302 includes a first film #1, a first film #2, a first film #3, a first film #4 and a first film #5. At this time, the first film #1, the first film #2, the first film #3, the first film #4 and the first film #5 are arranged in sequence from the first surface 301 to the direction away from the first surface 301. That is, the first film #1 is arranged on the first surface 301, the first film #2 is arranged on the first film #1, the first film #3 is arranged on the first film #2, the first film #4 is arranged on the first film #3, and the first film #5 is arranged on the first film #4, and the first film #5 is in contact with the air. If the refractive index of the first film #1 is n1, the refractive index of the first film #2 is n2, the refractive index of the first film #3 is n3, the refractive index of the first film #4 is n4, and the refractive index of the first film #5 is n5, then n1>n2>n3>n4>n5.

[0055] It is understandable that in the HUD system, when sunlight is incident from the air to the first surface 301 of the diffuser screen 300, reflection and refraction will occur. The reflected light may re-enter the imaging light path, thereby causing glare in the HUD system, affecting the imaging quality, and causing safety hazards to the driver. Therefore, after the first film system 302 is set on the first surface 301 of the diffuser screen 300, since the refractive index of the first film system 302 no longer causes a sudden change in the refractive index incident from the air to the first surface 301, but the refractive index gradually increases from the air to the first surface 301, the transmittance of sunlight can be increased and the reflectivity can be reduced. In addition, since the refractive indices of the multi-layer thin films are different, the light can be designed to interfere between the multi-layer films, thereby offsetting the reflection and further improving the transmittance.

[0056] Optionally, the first film system 302 is an anti-reflection film.

[0057] It should be noted that, no matter the first film system 302 is a multilayer film with a gradient refractive index, or an AR film with a high and low refractive index cross distribution, the refractive index of each layer is determined based on the refractive index of the material of the diffuser screen 300 and the target reflectivity of the incident light on the first film system. In other words, when the material of the diffuser screen and the target reflectivity of the system setting are determined, the number of layers, refractive index and thickness of the first film system 302 can be designed according to the material of the diffuser screen and the target reflectivity of the system setting, so that after the first film system 302 is set on the first surface of the diffuser screen 300, the reflectivity of the reflected light is less than or equal to the target reflectivity.

[0058] Optionally, the base material of the diffusion screen 300 is polymethyl methacrylate (PMMA), polycarbonate (PC), optical glass, etc., which is not limited in the present application.

[0059] In the embodiment of the present application, the first film system 302 can adopt physical vapor deposition (PVD) or chemical vapor deposition (CVD), such as atomic layer deposition (ALD), or sputtering, or wet coating and other processes, which are not limited in the present application. Among them, the processes such as PVD, CVD, ALD, sputtering and wet coating can refer to the existing related technical process descriptions, which will not be repeated here. It can be understood that the above-mentioned processes for generating the first film system 302 are currently common coating processes, and other coating processes to be developed in the future should also be applicable to the solutions of the present application.

[0060] In order to further eliminate the reflection of the first film system 302 and improve the transmission performance, a microstructure may be provided on the first surface 301, such as Figure 4 FIG. 4 is a schematic diagram of the structure of the second diffusion screen 400 provided in the embodiment of the present application. Figure 4 As shown, a microstructure 401 is disposed on the first surface 301 of the diffusion screen 400 , wherein the microstructure may also be referred to as a microstructure array, and the microstructure is used to reduce the reflectivity of incident light on the first surface 301 .

[0061] Optionally, the microstructure is a light-trapping structure. When a conical light-trapping structure is provided on the first surface 301 of the diffuser screen 400, the incident light will be scattered at the interface of the nano-light-trapping structure, thereby reducing the probability of reflection. Specifically, when light is irradiated onto the surface of the light-trapping structure, part of the light will be reflected back, while another part of the light will enter the interior of the light-trapping structure and leave the surface of the material after multiple reflections and refractions. Since there is a phase difference between the reflected light and the light entering the light-trapping structure, the two parts of light will interfere at the first surface 301, thereby further weakening the intensity of the reflected light.

[0062] When a light trapping structure is used, in the embodiment of the present application, the first film system 302 can be a bionic anti-reflection optical film based on the light trapping characteristics of butterfly scales, or a bionic anti-reflection optical film based on the light trapping characteristics of a moth eye structure, etc. The light trapping structure can be prepared by selective corrosion or etching, etc., which is not limited in the present application.

[0063] Figure 5 This is a schematic diagram of the structure of the third diffusion screen 500 provided in the embodiment of the present application. Figure 5 As shown, the diffusion screen 500 includes a first surface 301 and a second surface 502. A first film system 302 is disposed on the first surface 301, and the first film system 302 includes N layers of first films with different refractive indices, that is, Figure 5 The first film #1, the first film #2, ... the first film #N in the film system 502, N is an integer greater than or equal to 2. The second film system 502 includes M layers of second films with different refractive indices, that is, Figure 5 The second film #1, the second film #2, ..., the second film #M, M is an integer greater than or equal to 2. The first film system 302 is used to reduce the reflectivity of the incident light on the first film system 302. The second film system 502 is used to reduce the reflectivity of the incident light on the second film system 502.

[0064] Optionally, the refractive index of the multilayer first thin films of the first film system 302 gradually decreases in a direction away from the first surface 301 . The refractive index of the multilayer second thin films of the second film system 502 gradually decreases in a direction away from the second surface 501 .

[0065] Exemplarily, when N is equal to 5 and M is equal to 3, the first film system 302 includes the first film #1, the first film #2, the first film #3, the first film #4 and the first film #5. At this time, the first film #1, the first film #2, the first film #3, the first film #4 and the first film #5 are arranged in sequence in the direction away from the first surface 301. That is, the first film #1 is arranged on the first surface 501, the first film #2 is arranged on the first film #1, the first film #2 is arranged on the first film #3, the first film #3 is arranged on the first film #4, the first film #4 is arranged on the first film #5, and the first film #5 is in contact with the air. The second film system 502 includes the second film #1, the second film #2 and the second film #3. At this time, the second film #1, the second film #2 and the second film #3 are arranged in sequence in the direction away from the second surface 501. That is, the second film #1 is arranged on the second surface 501, the second film #2 is arranged on the second film #1, the second film #2 is arranged on the second film #3, and the first film #3 is in contact with the air. If the refractive index of the first film #1 is n11, the refractive index of the first film #2 is n12, the refractive index of the first film #3 is n13, the refractive index of the first film #4 is n14, and the refractive index of the first film #5 is n15, then n11>n12>n13>n14>n15. If the refractive index of the second film #1 is n21, the refractive index of the first film #2 is n22, and the refractive index of the first film #3 is n23, then n21>n22>n23.

[0066] Optionally, at least one of the first film system 302 and the second film system 502 is an anti-reflection film.

[0067] It should be noted that in Figure 5 In the diffuser screen 500 shown, the first film system 302 may be the same as the second film system 502 , or the first film system 302 may be different from the second film system 502 .

[0068] For example, when the first film system 302 is the same as the second film system 502, the films arranged on the first surface 301 and the second surface 502 of the diffuser 500 are exactly the same. When the second film system 502 is the same as the first film system 302, the relevant description of the second film system 502 can refer to the above Figure 3 and Figure 4 The instructions in the article are not repeated here.

[0069] For example, when the first film system 302 is different from the second film system 502, the first film system 302 and the second film system 502 may be different in at least one of the following:

[0070] The number of film layers of the first film system 302 is different from the number of film layers of the second film system 502; the refractive index of at least one first film in the multilayer first film is different from the refractive index of at least one second film in the multilayer second film; the thickness of at least one first film in the multilayer first film is different from the thickness of at least one second film in the multilayer second film.

[0071] When the number of film layers of the first film system 302 is different from the number of film layers of the second film system 502, the number of layers of the first film system 302 may be greater than the number of layers of the second film system 502. Figure 5 In the example, N is greater than M. Alternatively, the number of layers of the first film system 302 may be less than the number of layers of the second film system 502. Figure 5 In the equation, N is less than M.

[0072] When the refractive index of at least one of the multilayer first films of the first film system 302 is different from the refractive index of at least one of the multilayer second films of the second film system 502, it may be that the refractive index of one or more of the multilayer first films of the first film system 302 is different from the refractive index of one or more of the multilayer second films of the second film system 502. Exemplarily, if N is equal to M at this time, the refractive index of at least one of the first films in the first film system 302 may be different from the refractive index of at least one of the second films at the corresponding position in the second film system 502. For example, the refractive index of the first film #1 and the second film #1 is different, or the refractive index of the first film #1 and the second film #1 is different, and the refractive index of the first film #3 and the second film #3 is different, etc. Similarly, other different situations are not enumerated here.

[0073] When the thickness of at least one first film in the multilayer first films of the first film system 302 is different from the thickness of at least one second film in the multilayer second films of the second film system 502, the thickness of one or more first films in the multilayer first films of the first film system 302 may be different from the thickness of one or more first films in the multilayer second films of the second film system 502. Exemplarily, if N is equal to M at this time, the thickness of at least one first film in the first film system 302 may be different from the thickness of at least one second film in the corresponding position in the second film system 502. For example, the thickness of the first film #1 and the second film #1 is different, or the thickness of the first film #1 and the second film #1 is different, and the thickness of the first film #2 and the second film #2 is different, etc. Similarly, other different situations are not enumerated here.

[0074] It can be understood that when the diffuser 500 is used in a HUD system, compared with a single-sided film system, the double-sided film system can further reduce the reflected light of sunlight backflow and enhance the transmission of image light in the diffuser 500. That is, the diffuser 500 can not only reduce the reflectivity of stray light, but also reduce the loss of image light.

[0075] It can also be understood that the first film system 302 and the second film system 502 can both be film systems with a gradient refractive ratio, or both can be anti-reflective films, or one can be a film system with a gradient refractive ratio and the other can be an anti-reflective film, which is not limited in the present application.

[0076] It is understandable that the second film system 502 can be formed by processes such as PVD, CVD, ALD, sputtering and wet coating, and this application does not limit this.

[0077] In addition, in order to further eliminate the reflection of the first film system 502 and improve the transmission performance, a microstructure (such as a light trapping structure) can be set on the second surface 501 by selective corrosion or etching. Figure 6 As shown, a microstructure 601 is provided on the second surface 501 of the diffuser screen 600, thereby further reducing the intensity of the reflected light and increasing the intensity of the transmitted light. It is understandable that when a microstructure is provided on the second surface 501, the microstructure may be provided on the first surface 301, or not provided, according to the requirements for the reflectivity of the reflected light, and this application does not limit this.

[0078] Next, combining the above Figures 3 to 6 The diffusion screen shown in the figure illustrates some possible structures of the display device provided by the present application.

[0079] Figure 7 Schematic diagram of a display device 700 provided in an embodiment of the present application. Figure 7 As shown, the display device 700 includes a projection module 701, a diffusion screen 702, a first reflection element 703 and a second reflection element 704. The projection module 701 is used to project light onto the second surface (eg, Figure 7 The diffuser 702 is used to project image light from the first surface (such as Figure 7 The surface 1 in the figure transmits the image light from the projection module to the first reflective element, and generates a relay image on the first surface based on the image light from the projection module. The first reflective element 703 is used to reflect the image light emitted by the diffuser 702 to the second reflective element 704. The second reflective element 704 is used to reflect the image light reflected by the first reflective element 703 to the human eye. The diffuser 702 can be the above Figures 3 to 6 Any of the diffusers shown in , or based on the above Figures 3 to 6 A new diffuser for any diffuser design.

[0080] It can be understood that since the display device 700 provided in the present application adopts the diffusion screen provided in the present application for reducing the reflectivity of incident light (including any one of the above-mentioned diffusion screen 300, diffusion screen 400, diffusion screen 500 and diffusion screen 600), when sunlight enters the display device 700 from the outside, it is reflected by the second reflection element 704 and the first reflection element 703 in sequence to reach the diffusion screen 702. Since the surface of the diffusion screen 702 is provided with at least one of the first film system or the second film system, the reflected light of the sunlight at the diffusion screen 702 can be reduced, thereby avoiding the reflected light from re-entering the imaging light path and mixing with the image light, thereby preventing the glare phenomenon caused by the reflected light.

[0081] Optionally, the display device 700 may further include a dust cover 705. The dust cover 705 has the functions of isolating the external high temperature, preventing the internal temperature of the display device 700 from being too high, or preventing external dust from entering the device.

[0082] In order to further reduce the glare caused by the reflected light, in some embodiments, the perpendicular bisector of the diffusion screen 702 and the main light ray of the image light may form a certain angle, for example, an angle greater than 15°.

[0083] In the embodiment of the present application, the projection module 701 can adopt an LCoS display, an organic light-emitting diode (OLED) display, a liquid crystal display (LCD), a digital light processing (DLP) display or a micro-electro-mechanical system (MEMS) display, etc., which is not limited in the present application.

[0084] It should be noted that in Figure 7 In the display device 700 shown, the first reflective element 703 may be a concave mirror, a convex mirror or a plane mirror with a free-form surface, which is not limited in the present application.

[0085] It is understandable that the number of reflective elements included in the display device 700 is not limited to Figure 7 As shown, it can be adjusted accordingly according to needs.

[0086] As an example, Figure 8A possible structure of the projection module 701 provided in the embodiment of the present application. The projection module 701 includes a light source 711, a modulation module 712, and a projection device 713. According to the different display technologies adopted by the projection module 701, the modulation module 712 can be an LCoS modulator, or a DMD, or a transmissive spatial light modulator LCD, etc. Exemplarily, when the modulation module 712 is an LCoS modulator, the light source 711 can be a red, green, and blue light emitting diode (light emitting diode) light source, and together with the LCoS modulator constitute an LCoS display. When the modulation module 712 is a DMD, it can be a DMD modulator under MEMS control, and a laser light source or an LED light source can be used to form a DLP display. Alternatively, when the modulation module 712 is an LCD modulator, the light source 711 can use a linear light source of a red, green, and blue cold cathode fluorescent tube, and form an LCD display with the LCD modulator. The projection device 713 can be a projection lens.

[0087] Optionally, in order to improve the projection quality and / or reduce the volume of the projection module 701, in some embodiments, the projection module 701 further includes a refraction module 714, or the projection module 701 further includes a polarization conversion module 714. When the projection module 701 includes a refraction module 714, the refraction module 714 may be one or more lenses (used to focus the energy of the light beam, ensure the energy of the light beam or diffuse the light spot, and increase the field of view of the projection), and / or one or more prisms (used to fold the light path and reduce the volume of the projection module), etc., which are not limited in this application. When the projection module 701 includes a polarization conversion module 714, the polarization conversion module 714 is used to change the polarization state of the image light.

[0088] As an example, Fig. 9 The present application provides a possible structure of the projection module 701 in which the modulation module 712 is a DMD. Fig. 9 As shown, the light source 711 includes a first monochromatic light array 911, a second monochromatic light array 912, a third monochromatic light array 913, dichroic filters 921 and 922, and a lens group 933. The three monochromatic light arrays can correspond to monochromatic light of three primary colors, including red light, blue light, and green light. In order to improve the utilization rate of light energy, in some embodiments, a collimating lens is further arranged after the monochromatic light array, as shown in FIG. Fig. 9 The collimating lens 9111, the collimating lens 9112 and the collimating lens 9113 in the projection module 701 are provided. The refraction module 714 includes a lens group and a prism. Figure 7In the display device 700 shown, the first monochromatic light array 911, the second monochromatic light array 912, and the third monochromatic light array 913 respectively emit corresponding monochromatic lights. The three monochromatic lights pass through the dichroic filters 921 and 922 and are incident on the lens group of the refractive module. After being emitted from the lens group, they are incident on the DMD 712 through the prism. The DMD 712 modulates the input light beam based on the data information of the input image and outputs image light. The image light is transmitted through the prism and is incident on the projection lens 713. The image light is emitted toward the diffusion screen through the projection lens 713.

[0089] When the display device 700 is applied to a vehicle, Fig.10 The display device 700 provided in the embodiment of the present application is applied to the optical path 1000 of a vehicle. Specifically, the projection module 701 generates image light and projects the image light to the diffusion screen 702. While the diffusion screen 702 generates a relay image, it transmits the image light from the projection module to the first reflection element 703. Then, the first reflection element 703 reflects the image light from the diffusion screen 702 to the second reflection element 704. After the image light is reflected by the second reflection element 704 and transmitted through the light shield 705, it is reflected to the human eye through the windshield 1001 for imaging. Among them, the image generated by the image light can be an augmented reality display image, which is used to display information such as indication information and navigation information of external objects. Alternatively, the image generated by the image light can be a status display image, which is used to display the status information of the vehicle. Taking a car as an example, the status information of the vehicle is not limited to information such as driving speed, mileage, fuel level, water temperature and light status.

[0090] It is understandable that the means of transportation to which the present application scheme can be applied include but are not limited to cars, airplanes, trains or ships.

[0091] In addition, the embodiment of the present application further provides a means of transportation, which is any of the above-mentioned display devices. The means of transportation includes but is not limited to a car, an airplane, a train, or a ship.

[0092] Fig.11 This is a circuit diagram of a display device provided in an embodiment of the present application. Fig.11As shown, the circuit in the display device mainly includes a host CPU 1201, an external memory interface 1202, an internal memory 1203, an audio module 1204, a video module 1205, a power module 1206, a wireless communication module 1207, an I / O interface 1208, a video interface 1209, a display circuit 1210 and a modulator 1212. Among them, the host processor 1201 and its peripheral components, such as the external memory interface 1202, the internal memory 1203, the audio module 1204, the video module 1205, the power module 1206, the wireless communication module 1207, the I / O interface 1208, the video interface 1209, and the display circuit 1210 can be connected through a bus. The host processor 1201 can be called a front-end processor.

[0093] In addition, the circuit diagrams shown in the embodiments of the present application do not constitute a specific limitation on the display device. In other embodiments of the present application, the display device may include more or fewer components than shown in the figure, or combine certain components, or split certain components, or arrange the components differently. The components shown in the figure may be implemented in hardware, software, or a combination of software and hardware.

[0094] The main processor 1201 includes one or more processing units, for example, the main processor 1201 may include an application processor (AP), a modem processor, a graphics processor (GPU), an image signal processor (ISP), a controller, a video codec, a digital signal processor (DSP), a baseband processor, and / or a neural network processor (NPU), etc. Different processing units may be independent devices or integrated in one or more processors.

[0095] The main processor 1201 may also be provided with a memory for storing instructions and data. In some embodiments, the memory in the main processor 1201 is a cache memory. The memory may store instructions or data that the main processor 1201 has just used or cyclically used. If the main processor 1201 needs to use the instruction or data again, it may be directly called from the memory. This avoids repeated access, reduces the waiting time of the main processor 1201, and thus improves the efficiency of the system.

[0096] In some embodiments, the display device may further include a plurality of input / output (I / O) interfaces 1208 connected to the main processor 1201. The interface 1208 may include an inter-integrated circuit (I2C) interface, an inter-integrated circuit sound (I2S) interface, a pulse code modulation (PCM) interface, a universal asynchronous receiver / transmitter (UART) interface, a mobile industry processor interface (MIPI), a general-purpose input / output (GPIO) interface, a subscriber identity module (SIM) interface, and / or a universal serial bus (USB) interface, etc. The above-mentioned I / O interface 1208 may be connected to devices such as a mouse, a touchpad, a keyboard, a camera, a speaker / speaker, a microphone, etc., and may also be connected to physical buttons on the display device (such as a volume button, a brightness adjustment button, a power button, etc.).

[0097] The external memory interface 1202 can be used to connect an external memory card, such as a Micro SD card, to expand the storage capacity of the display device. The external memory card communicates with the main processor 1201 through the external memory interface 1202 to implement a data storage function.

[0098] The internal memory 1203 can be used to store computer executable program codes, which include instructions. The internal memory 1203 may include a program storage area and a data storage area. Among them, the program storage area may store an operating system, an application required for at least one function (such as a call function, a time setting function, etc.), etc. The data storage area may store data created during the use of the display device (such as a phone book, world time, etc.), etc. In addition, the internal memory 1203 may include a high-speed random access memory, and may also include a non-volatile memory, such as at least one disk storage device, a flash memory device, a universal flash storage (Universal Flash Storage, UFS), etc. The main processor 1201 executes various functional applications and data processing of the display device by running instructions stored in the internal memory 1203 and / or instructions stored in a memory provided in the main processor 1201.

[0099] The display device can implement audio functions such as music playing and calls through the audio module 1204 and the application processor.

[0100] The audio module 1204 is used to convert digital audio information into analog audio signal output, and is also used to convert analog audio input into digital audio signals. The audio module 1204 can also be used to encode and decode audio signals, such as playing or recording. In some embodiments, the audio module 1204 can be arranged in the main processor 1201, or some functional modules of the audio module 1204 can be arranged in the main processor 1201.

[0101] The video interface 1209 can receive external audio and video signals, which can be specifically a high-definition multimedia interface (HDMI), a digital video interface (DVI), a video graphics array (VGA), a display port (DP), etc. The video interface 1209 can also output video to the outside. When the display device is used as a head-up display, the video interface 1209 can receive speed signals and power signals input from peripheral devices, and can also receive external AR video signals. When the display device is used as a projector, the video interface 1209 can receive video signals input from an external computer or terminal device.

[0102] The video module 1205 can decode the video input by the video interface 1209, for example, by performing H.264 decoding. The video module can also encode the video collected by the display device, for example, by performing H.264 encoding on the video collected by the external camera. In addition, the main processor 1201 can also decode the video input by the video interface 1209, and then output the decoded image signal to the display circuit 1210.

[0103] The display circuit 1210 and the modulator 1212 are used to display the corresponding image. In this embodiment, the video interface 1209 receives an external video source signal, and the video module 1205 decodes and / or digitally processes and outputs one or more image signals to the display circuit 1210. The display circuit 1210 drives the modulator 1212 to image the incident polarized light according to the input image signal, and then outputs the image light. In addition, the main processor 1201 can also output one or more image signals to the display circuit 1210.

[0104] In this embodiment, the display circuit 1210 and the modulator 1212 belong to the above Figure 8The electronic components in the modulation unit 712 shown, the display circuit 1210 can be called a driving circuit.

[0105] The power module 1206 is used to provide power to the main processor 1201 and the light source 1200 according to the input power (e.g., direct current), and the power module 1206 may include a rechargeable battery, which can provide power to the main processor 1201 and the light source 1200. The light emitted by the light source 1200 can be transmitted to the modulator 1212 for imaging, thereby forming an image light signal.

[0106] The wireless communication module 1207 enables the display device to communicate wirelessly with the outside world, and can provide wireless local area networks (WLAN) (such as wireless fidelity (Wi-Fi) networks), Bluetooth (BT), global navigation satellite system (GNSS), frequency modulation (FM), near field communication technology (NFC), infrared technology (IR) and other wireless communication solutions. The wireless communication module 1207 can be one or more devices integrating at least one communication processing module. The wireless communication module 1207 receives electromagnetic waves via an antenna, modulates the frequency of the electromagnetic wave signal and performs filtering processing, and sends the processed signal to the main processor 1201. The wireless communication module 1207 can also receive the signal to be sent from the main processor 1201, modulate the frequency of the signal, amplify it, and convert it into electromagnetic waves for radiation through the antenna.

[0107] In addition, in addition to being input through the video interface 1209, the video data decoded by the video module 1205 can also be wirelessly received through the wireless communication module 1207 or read from an external memory. For example, the display device can receive video data from a terminal device or an in-vehicle entertainment system through the wireless LAN in the vehicle, and the display device can also read audio and video data stored in an external memory.

[0108] The above display device can be installed on a vehicle, see Fig.12 , Fig.12 A schematic diagram of a possible functional framework of a vehicle provided in an embodiment of the present application.

[0109] like Fig.12As shown, the functional framework of the vehicle may include various subsystems, such as the sensor system 12, the control system 14, one or more peripheral devices 16 (one is shown as an example), the power supply 18, the computer system 20 and the head-up display system 22. Optionally, the vehicle may also include other functional systems, such as an engine system that provides power for the vehicle, etc., which is not limited in this application.

[0110] The sensor system 12 may include a number of detection devices, which can sense the measured information and convert the sensed information into electrical signals or other required forms of information output according to a certain rule. As shown in the figure, these detection devices may include a global positioning system (GPS), a vehicle speed sensor, an inertial measurement unit (IMU), a radar unit, a laser rangefinder, a camera device, a wheel speed sensor, a steering sensor, a gear position sensor, or other components for automatic detection, etc., and the present application does not limit them.

[0111] The control system 14 may include several components, such as the steering unit, brake unit, lighting system, automatic driving system, map navigation system, network timing system and obstacle avoidance system shown in the figure. Optionally, the control system 14 may also include components such as a throttle controller and an engine controller for controlling the vehicle's speed, which are not limited in this application.

[0112] The peripheral device 16 may include several components, such as the communication system, touch screen, user interface, microphone, and speaker shown in the figure. The communication system is used to realize network communication between the vehicle and other devices other than the vehicle. In practical applications, the communication system may use wireless communication technology or wired communication technology to realize network communication between the vehicle and other devices. The wired communication technology may refer to communication between the vehicle and other devices through network cables or optical fibers.

[0113] The power source 18 represents a system that provides power or energy for the vehicle, which may include but is not limited to a rechargeable lithium battery or a lead-acid battery, etc. In practical applications, one or more battery components in the power source are used to provide power or energy for starting the vehicle, and the type and material of the power source are not limited in this application.

[0114] Several functions of the vehicle are controlled and implemented by the computer system 20. The computer system 20 may include one or more processors 2001 (one processor is shown as an example in the figure) and a memory 2002 (also referred to as a storage device). In actual applications, the memory 2002 is also inside the computer system 20, or it may be outside the computer system 20, for example, as a cache in the vehicle, etc., which is not limited in this application.

[0115] in,

[0116] The processor 2001 may include one or more general-purpose processors, such as a graphics processing unit (GPU). The processor 2001 may be used to run related programs or instructions corresponding to the programs stored in the memory 2002 to implement corresponding functions of the vehicle.

[0117] The memory 2002 may include a volatile memory, such as a RAM; the memory may also include a non-volatile memory, such as a ROM, a flash memory, a HDD or a solid-state drive SSD; the memory 2002 may also include a combination of the above-mentioned types of memories. The memory 2002 may be used to store a set of program codes or instructions corresponding to the program codes, so that the processor 2001 calls the program codes or instructions stored in the memory 2002 to implement the corresponding functions of the vehicle. In the present application, a set of program codes for vehicle control may be stored in the memory 2002, and the processor 2001 calls the program codes to control the safe driving of the vehicle. How to achieve safe driving of the vehicle is described in detail below in the present application.

[0118] Optionally, in addition to storing program codes or instructions, the memory 2002 may also store information such as road maps, driving routes, sensor data, etc. The computer system 20 may be combined with other elements in the vehicle functional framework diagram, such as sensors in the sensor system, GPS, etc., to implement relevant functions of the vehicle. For example, the computer system 20 may control the driving direction or driving speed of the vehicle based on the data input from the sensor system 12, which is not limited in this application.

[0119] The head-up display system 22 may include several components, such as the windshield shown in the figure, a controller and a head-up display. The controller 222 is used to generate images according to user instructions (for example, images containing vehicle status such as vehicle speed, battery / fuel level, and images of augmented reality AR content), and send the image to the head-up display for display; the head-up display may include an image generation unit and a reflector combination, and the windshield is used to cooperate with the head-up display to realize the optical path of the head-up display system so that the target image is presented in front of the driver. Among them, the functions of some components in the head-up display system can also be implemented by other subsystems of the vehicle. For example, the controller can also be a component in the control system.

[0120] Among them, this application Fig.12The four subsystems shown are sensor system 12, control system 14, computer system 20 and head-up display system 22, which are only examples and do not constitute limitations. In actual applications, vehicles can combine several components in the vehicle according to different functions to obtain subsystems with corresponding different functions. In actual applications, vehicles can include more or fewer systems or components, which is not limited in this application.

[0121] The above-mentioned means of transportation can be a car, truck, motorcycle, bus, ship, airplane, helicopter, lawn mower, recreational vehicle, amusement park vehicle, construction equipment, tram, golf cart, train, and cart, etc., and the embodiments of the present application are not particularly limited.

[0122] Unless otherwise defined, technical or scientific terms used herein shall have the common meanings understood by one of ordinary skill in the art to which the present disclosure belongs.

[0123] The above description is only an embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made on the basis of the present application shall be included in the protection scope of the present application.

Claims

1. A diffusion screen, characterized in that: include: First surface, A first film system is disposed on the first surface, wherein the first film system includes a plurality of first thin films with different refractive indices, and the first film system is used to reduce the reflectivity of incident light on the first film system.

2. The diffuser screen according to claim 1, characterized in that: The refractive index of the multi-layer first thin film gradually decreases in a direction away from the first surface.

3. The diffuser screen according to claim 1 or 2, characterized in that: The diffusion screen further includes a second surface, the second surface is opposite to the first surface, and the first film system is disposed on the second surface.

4. The diffuser screen according to claim 3, characterized in that: The refractive index of the multi-layer first thin film gradually decreases in a direction away from the second surface.

5. The diffuser screen according to claim 1 or 2, characterized in that: The diffusion screen further includes a second surface, the second surface is opposite to the first surface, a second film system is arranged on the second surface of the diffusion screen, the second film system includes a plurality of second thin films with different refractive indices, and the second film system is used to reduce the reflectivity of incident light on the second film system. The first film system and the second film system are different in at least one of the following: The number of layers of the first film system and the second film system, the refractive index of at least one first film in the multilayer first film and the refractive index of at least one second film in the multilayer second film, the thickness of at least one first film in the multilayer first film and the thickness of at least one second film in the multilayer second film.

6. The diffuser screen according to claim 5, characterized in that: The refractive index of the multi-layer second thin film gradually decreases in a direction away from the second surface.

7. The diffuser screen according to claim 5, characterized in that: At least one of the first film system and the second film system is an anti-reflection (AR) film.

8. The diffuser screen according to any one of claims 5 to 7, characterized in that: At least one of the first film system and the second film system includes a microstructure, and the microstructure is used to reduce the reflectivity of the incident light on the film system including the microstructure.

9. The diffuser screen according to any one of claims 1 to 8, characterized in that: The refractive index of the first film system is determined based on the refractive index of the diffusion screen and the target reflectivity of the incident light in the first film system.

10. A display device, characterized in that: The device comprises a projection module, a first reflective element, a second reflective element and a diffusion screen as claimed in any one of claims 1 to 9, wherein: The projection module is used to project image light onto the second surface of the diffusion screen; the diffusion screen is used to transmit the image light from the projection module from the first surface to the first reflection element, and to generate a relay image on the first surface based on the image light from the projection module; The first reflecting element is used to reflect the image light from the diffusion screen to the second reflecting element; The second reflecting element is used to reflect the image light from the first reflecting element toward human eyes.

11. The display device according to claim 10, characterized in that: An angle between a normal line of the second surface and the image light incident on the second surface is greater than or equal to 15°.

12. A means of transport, characterized in that: The device comprises the display device and the windshield according to claim 10 or 11, The windshield is used to reflect the image light from the display device to human eyes.

13. A vehicle-mounted system, characterized in that: Includes the display device according to claim 10 or 11.

Images