Optical waveguide module and transparent display system

Abstract

The invention provides an optical waveguide module and a transparent display system, and relates to the technical field of display, the optical waveguide module comprises an optical waveguide body, a coupling-in grating area and a coupling-out grating area are formed on the optical waveguide body, the coupling-out grating area forms a dual-channel grating, incident light vertically enters the optical waveguide body through the coupling-in grating area, and the coupling-out grating area forms a dual-channel grating. The light is divided into two beams of deflection light rays to be transmitted through volume holographic diffraction when passing through a double-channel grating of the coupling-out grating area, the two beams of deflection light rays are vertically emitted from the back face of the coupling-out grating area, and the two beams of deflection light rays and the optical axis form a deflection angle of + a and a deflection angle of-a respectively. Necessary information such as driving and driving states in the front view direction of a driver is provided and projected to the front of the driver in a transparent background mode, the driver is prevented from lowering the head to view an instrument, interference to the sight of the driver is reduced, and driving safety and experience are improved. Moreover, a larger, brighter and farther display effect can be provided, the size of the module can be relatively controlled within a smaller range, and the cost advantage is achieved.

Description

Technical Field

[0001] This application relates to the field of display technologies, and particularly to an optical waveguide module and a transparent display system. Background Art

[0002] Head-up display technology is a technology that directly projects important information onto the windshield, enabling the driver to view information such as speed and navigation without having to look down. This technology reduces the driver's line-of-sight shift and improves driving safety. This technology generally uses W-HUD (windshield type head-up display) technology for projection display. The projection is carried out through a HUD (head-up display) projection lens onto a HUD reflector. The HUD reflector reflects the image onto a curved lens on the mainframe housing. The curved lens converts the image optical path onto an optical film on the upright front windshield of the bus. Finally, the driver can see the corresponding virtual image.

[0003] Although HUD technology reduces the line-of-sight shift, the information display area is limited and it is impossible to display a large area of information simultaneously. For large-size displays, it is necessary to match huge devices. Traditional HUD and transparent display technologies require complex installation and calibration processes, and the maintenance cost is relatively high. This increases the manufacturing and operating costs of vehicles and limits the popularization and application of the technology. Summary of the Invention

[0004] The purpose of the embodiments of this application is to provide an optical waveguide module and a transparent display system, which can provide a large display area and a large horizontal viewing angle, and are easy to install and have a low cost.

[0005] On one hand, an embodiment of this application provides an optical waveguide module, including: an optical waveguide body, on which an input grating area and an output grating area are formed. The output grating area forms a dual-channel grating. Incident light is perpendicularly incident on the optical waveguide body through the input grating area, and when passing through the dual-channel grating of the output grating area, it undergoes volume holographic diffraction and is divided into two deflected light beams for propagation. The two deflected light beams are perpendicularly emitted from the back of the output grating area respectively, and the two deflected light beams form a deflection angle of +a and -a with the optical axis respectively.

[0006] Optionally, the dual-channel grating has a first channel and a second channel symmetrically arranged on both sides of the optical axis. Through the volume holographic diffraction effects of the first channel and the second channel, the incident light forms two deflected light beams with deflection angles of +a and -a with the optical axis respectively.

[0007] Optionally, the output grating area and the input grating area are coplanarly arranged on one side along the thickness direction of the optical waveguide body, and the direction of the optical axis is perpendicular to the thickness direction of the optical waveguide body.

[0008] Optionally, the two deflected light beams undergo volume holographic diffraction in the output grating region and are emitted from the back surface of the output grating region in a direction perpendicular to the optical waveguide body.

[0009] Optionally, the incident angle of the incident light beam on the optical waveguide body is less than the total reflection angle of the optical waveguide body.

[0010] Optionally, the optical waveguide body is a volume holographic optical waveguide, and the input grating region and the output grating region are volume holographic diffraction grating regions.

[0011] Optionally, the material of the optical waveguide body includes tempered glass.

[0012] Optionally, the materials of the input grating region and the output grating region include photopolymers.

[0013] On the other hand, an embodiment of the present application provides a transparent display system, including: the above-mentioned optical waveguide module, an optical engine module, a host module, and an interactive operation module, and the interactive operation module, the host module, and the optical engine module are connected in sequence.

[0014] Optionally, the optical engine module is correspondingly arranged in the input grating region of the optical waveguide module.

[0015] In the optical waveguide module and the transparent display system provided by the embodiments of the present application, an input grating region and an output grating region are formed on the optical waveguide body, the output grating region forms a dual-channel grating, the incident light beam vertically enters the optical waveguide body through the input grating region, and when passing through the dual-channel grating, it undergoes volume holographic diffraction and is divided into two deflected light beams for propagation. The two deflected light beams are respectively vertically emitted from the back surface of the output grating region, and the angles between the two deflected light beams and the optical axis are +a deflection angle and -a deflection angle respectively. Provide necessary information such as the driving and driving states in the driver's forward viewing direction, and project it in the form of a transparent background in front of the driver, avoiding the driver from looking down at the instrument panel, reducing the interference to the driver's line of sight, improving driving safety and experience; and can provide a larger, brighter, and farther display effect, and the module volume can be relatively controlled within a smaller range, having a cost advantage. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings required to be used in the embodiments of the present application. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.

[0017] Figure 1a is one of the schematic structural diagrams of the optical waveguide module provided in this embodiment;

[0018] Figure 1b This is the second structural diagram of the optical waveguide module provided in this embodiment;

[0019] Figure 2 This is the third structural diagram of the optical waveguide module provided in this embodiment;

[0020] Figure 3 This is the fourth structural diagram of the optical waveguide module provided in this embodiment;

[0021] Figure 4 This is the fifth structural diagram of the optical waveguide module provided in this embodiment;

[0022] Figure 5 This is a principle diagram of light vectors within the unit circle size of the optical waveguide module provided in this embodiment;

[0023] Figure 6 is a light propagation diagram of the optical waveguide module structure provided in this embodiment;

[0024] Figure 7 This is one of the structural diagrams of the transparent display system provided in this embodiment;

[0025] Figure 8 This is the second structural diagram of the transparent display system provided in this embodiment.

[0026] Icon: 10-optical waveguide module; 11-optical waveguide body; 110-incoupling grating area; 111-dual-channel grating; HOE1-first channel; HOE2-second channel; 112-outcoupling grating area; 20-optical-mechanical module; 30-host module; 40-interactive operation module; In-incident light; Out-outcoupling light; S-optical axis direction; T-thickness direction. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application.

[0028] In the description of this application, it should be noted that the terms "inner" and "outer" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, or the orientations or positional relationships in which the product of this application is typically placed when in use. These terms are intended solely to facilitate the description of this application and simplify the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first" and "second" and the like are used solely for distinction and should not be construed as indicating or implying relative importance.

[0029] It should also be noted that, unless otherwise clearly specified and limited, the terms "arranged" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium, and can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific situations.

[0030] The embodiment of the present application provides an optical waveguide module 10, which can be applied to a standing optical waveguide transparent display system in various driving scenarios, provide necessary information such as the driving and driving states in the front view direction of the driver, and project it in the form of a transparent background in front of the driver, avoiding the driver from looking down at the instrument panel, reducing the interference to the driver's line of sight, improving driving safety and experience; and can provide a larger, brighter and farther display effect, and the volume of the module can be relatively controlled within a smaller range.

[0031] Specifically, referring to Figure 1a , Figure 1b , Figure 2 As shown, the optical waveguide module 10 provided by the embodiment of the present application includes: an optical waveguide body 11, an input grating area 110 and an output grating area 112 are formed on the optical waveguide body 11, and the output grating area 112 forms a dual-channel grating 111. The incident light In is perpendicularly incident on the front surface of the optical waveguide body 11 through the input grating area 110, and then undergoes volume holographic diffraction when passing through the dual-channel grating 111 and is divided into two deflected light beams for propagation. The two deflected light beams are respectively perpendicularly emitted from the back surface of the output grating area 112, and the two deflected light beams form a deflection angle of +a and -a with the optical axis respectively.

[0032] The incident light In is provided by the optical engine module 20, and the optical engine module 20 is correspondingly arranged in the input grating area 110. The optical waveguide body 11 of the present application is a volume holographic optical waveguide. Among them, the input grating area 110 and the output grating area 112 are also volume holographic gratings and can undergo volume holographic diffraction.

[0033] Among them, the input grating area 110 is a single-layer grating, and the output grating area 112 is a double-layer grating to form a dual-channel grating 111. The dual-channel grating 111 has a first channel HOE1 and a second channel HOE2 symmetrically arranged on both sides of the optical axis. The incident light In undergoes volume holographic diffraction of the first channel HOE1 and the second channel HOE2, and respectively forms two deflected light beams propagating with a deflection angle of +a and -a with the optical axis.

[0034] The incident light In provided by the optical-mechanical module 20 irradiates the light-coupling grating region 110 on the front surface of the optical waveguide body 11. The incident light In forms a deflection angle through the volume holographic diffraction grating of the light-coupling grating region 110. The incident angle of the incident light In into the optical waveguide body 11 is less than the total reflection angle of the optical waveguide body 11. Therefore, total reflection occurs inside the optical waveguide body 11 and the light propagates upward, as Figure 3 shown; then it reaches the dual-channel grating 111 of the light-coupling grating region 112. The incident light In simultaneously undergoes volume holographic diffraction through two channels. Part of the incident light In passes through a layer of volume holographic grating at a specific angle (the first channel HOE1 of the dual-channel grating 111), generates volume holographic diffraction and deflects at an angle, so that the light angle forms a deflection angle of +a with the primary propagation direction (the optical axis direction S) for total reflection. The other incident light In simultaneously passes through a two-layer volume holographic grating (the second channel HOE2 of the dual-channel grating 111), generates volume holographic diffraction, and the light angle forms a deflection angle of -a with the primary propagation direction (the optical axis direction S) for total reflection; where + and - only represent the directions of the deflection angles. In some embodiments, the deflection angles can be +60° and -60° for deflection; the incident light In generates volume holographic diffraction through the dual-channel grating 11 and diffracts in a direction perpendicular to the optical waveguide body 11, so that the two deflected light beams are respectively emitted from the optical waveguide body 11 to form the output light Out. The output light Out is irradiated on the position of the driver's eyes from the back surface of the light-coupling grating region 112, as Figure 3 , Figure 4 shown.

[0035] It can be seen from Figure 3 that the light-coupling grating region 112 and the light-coupling grating region 110 are coplanarly arranged on one side of the optical waveguide body 11 in the thickness direction T, and the direction of the optical axis is perpendicular to the thickness direction T of the optical waveguide body 11. The two deflected light beams undergo volume holographic diffraction in the light-coupling grating region 112 and are emitted from the back surface of the optical waveguide body 11 in a direction perpendicular to the optical waveguide body 11.

[0036] In some embodiments, the optical waveguide module 10 is mainly composed of tempered glass and a photopolymer material. The tempered glass serves as a total reflection medium to achieve the effect of lossless light propagation and becomes the material of the optical waveguide body 11; the photopolymer material serves as the material of the volume holographic diffraction gratings (the light-coupling grating region 110 and the light-coupling grating region 112) to achieve the effect of light angle deflection.

[0037] In addition, using tempered glass as the optical waveguide body 11 ensures that in the event of an extreme accident, the glass will not break or form sharp fragments that cause secondary harm to the driver.

[0038] The photopolymer material is mainly attached to the tempered glass in the form of a film to form the above-mentioned volume holographic diffraction grating, which greatly reduces the cost and process difficulty in terms of processing and manufacturing. The outer surface of the film can also well protect the internal photopolymer material. In addition, the photopolymer material also has the effect of bonding into a block after the glass is broken, avoiding the glass from breaking into particles and causing injury to the driver.

[0039] Figure 3 , Figure 4 The optical-mechanical module 20 shown emits light rays and the propagation process inside the volume holographic optical waveguide. The incident light ray In of the optical-mechanical module 20 passes through the coupling grating region 110, and makes the first angular deflection of the vertically incident incident light ray In, so that the angle θ at which the incident light ray In enters the optical waveguide body 11 is less than the total reflection angle of the optical waveguide body 11. Subsequently, it passes through the volume holographic diffraction grating of the first channel HOE1 of the dual-channel grating 111, generates a positive 60° angular deflection to propagate through the first channel HOE1 and is coupled out by the coupling-out grating region 112. At the same time, it passes through the volume holographic diffraction grating of the second channel HOE2 of the dual-channel grating 111 to generate a negative 60° angular deflection and propagate through the second channel HOE2 and is coupled out by the coupling-out grating region 112. The optical paths of the two channels are coupled out and spliced into a complete field of view, and finally image information is provided for the driver.

[0040] The technical principle of the optical waveguide is to use the optical waveguide material for diffraction and total reflection of glass, and the image can be transmitted from the display source to a position far from the display source for display. This technology can display the image with a transparent background. The optical waveguide technology can be divided into geometric optical waveguides and diffraction optical waveguide technologies. Geometric optical waveguides mainly include array optical waveguides, and diffraction optical waveguide technologies include surface relief grating waveguides and volume holographic gratings;

[0041] The array waveguide technology passes through the core element semi-transmissive and semi-reflective mirror array. The light rays of the image source are coupled into the waveguide and transmitted by total reflection. After reaching the semi-transmissive and semi-reflective mirror array, they are reflected into the human eye. The advantage of the array optical waveguide is that it can correspond to a larger eyebox and the image display effect is good. However, the semi-transmissive and semi-reflective mirror process is difficult and the overall yield is difficult to guarantee, and it is difficult to process large-size array waveguides;

[0042] In the surface relief grating waveguide of the diffraction optical waveguide technology, the core element grating is processed into a periodic shape by processes such as coating and etching on a glass substrate and a coating film. In addition, the required periodic shape, that is, the grating, can also be "pressed" on the thin film layer through nanoimprinting technology; however, as the size increases, the processing difficulty will increase and the yield will decrease, resulting in higher costs.

[0043] The volume holographic grating used in each grating area of the present application is also a type of diffractive optical waveguide. By using an interference pattern excited by a laser, a photosensitive material attached to a substrate is exposed to process a periodic shape; the volume holographic grating waveguide has a smaller volume, with advantages in design cost and manufacturing cost, high production efficiency, and high energy utilization rate.

[0044] Referring again to Figure 5 , Figure 5 FIG. shows a schematic diagram of the light vector within the unit circle of the volume holographic diffractive optical waveguide body 11 of the optical waveguide module 10. The light vectors within the unit circle are deflected by the first channel HOE1 and the second channel HOE2 of the dual-channel grating 111, and then combined to obtain the output coupling.

[0045] As Figure 6 shown, when the incident light In passes through the input coupling grating area 110, the incident light In diffracts through the first channel HOE1 within the unit circle. Part of the light is deflected to form the output coupling light and is output from the back of the output coupling grating area 112, and part of the light then enters the first channel HOE1 of the next unit size and is output within the next unit circle; the incident light In forms half of the field of view through the first channel HOE1, and the path channel of the second channel HOE2 forms the other half of the field of view. Finally, the light passing through the dual-channel gratings 111 on both sides is spliced into a complete field of view. For the optical waveguide module fabricated in this way, a wide field of view angle can be formed only through these two areas, namely the output coupling grating area 112 and the input coupling grating area 110, such that the present optical waveguide module has a wider viewing angle along the left-right direction (the length direction of the optical waveguide body 11) in FIG. 1. Since the viewing angle of the human eye is wider horizontally and narrower vertically, the left-right wide-screen transparent display system exactly meets the viewing requirements of the human eye. The vertical transparent display system matching the optical waveguide module 10 of the present application redesigned a vertical transparent display screen for the cockpit of each scenario, providing the driver with a transparent display field of view with a wider viewing angle.

[0046] Based on this, as Figure 7 shown, an embodiment of the present application also discloses a transparent display system, including the optical waveguide module 10 as described in any one of the above, an optical engine module 20 correspondingly disposed in the input coupling grating area 110 of the optical waveguide module 10, as well as a host module 30 and an interactive operation module 40. The interactive operation module 40, the host module 30, and the optical engine module 20 are connected in sequence.

[0047] The display method of the transparent display system of this application adopts a new type of volume holographic optical waveguide display method. The optical waveguide module 10 is a display module for the driver to view. Driving information will be projected onto the distant sky, forming display information on a transparent background. The optical engine module 20 is used to generate a projection image light source. The host module 30 is a computer operation center, which is used to process information such as display and interaction and control the entire vehicle and driving state. The interaction operation module 40 is a driver control and operation module and an interaction entrance of the display system.

[0048] The overall design operation process is that the driver controls the driving or navigation state through operation methods such as controlling buttons, knobs, steering wheels, joysticks, and pushing engines on the interaction operation module 40. The host module 30 processes the operation actions input by the driver, converts them into graphical driving or navigation information, and then projects the information image onto the optical waveguide module 10 through the optical engine module 20, and finally forms an image feedback of the navigation information in front of the driver's eyes.

[0049] Figure 8 It shows the overall structure diagram of the optical waveguide display system erected in front of the driver's seat. This cockpit is introduced as a schematic diagram of the mechanism. The display system uses the optical waveguide module 10, and the optical waveguide module 10 provides an image with a large field of view, far projection, high brightness, transparency and no occlusion for the transparent display system, providing imaging information in front of the driver.

[0050] The transparent display system provided by this application uses volume holographic optical waveguide technology as a transparent display solution, reducing the use of traditional cockpit display instrument panels and liquid crystal displays, and reducing the driver's action of looking down to view driving information; through the transparent screen display erected by the optical waveguide, a virtual image is formed in the distance directly in front of the driver, and a large field of view waveguide is realized through dual-channel technology, greatly increasing the horizontal field of view angle and the overall eye box area, increasing the viewing angle of the driver, and improving the problem of the small field of view of the W-HUD. The entire transparent imaging display system avoids the obstruction of the driver's line of sight. This volume holographic optical waveguide solution can achieve better display in front of the driver in terms of field of view angle, imaging quality, and brightness, and through the interaction operation and the processing center of the computer host, it realizes the interaction between the driver and the display system and the information display during the operation process.

[0051] This application uses an optical waveguide module 10. By means of dual-channel technology, a volume holographic grating is fabricated to form an optical waveguide with a large horizontal field of view angle, which is applied to various driving scenarios. It can be used in vertical driving scenarios on the front windshield of buses and coaches, etc. A vertical optical waveguide display system can be directly constructed on the front windshield. For example, it can be applied to the driving scenarios of buses, coaches, trucks, subways, and the cockpit of eTVOL. A transparent display system is constructed through an external vertical glass; a display template in the transparent display system inside the cockpit is constructed through a vertical waveguide sheet, and through the dual-channel volume holographic optical waveguide technology, the production of the vertical optical waveguide is realized, providing the driver with a transparent display system with a large display area and a large horizontal viewing angle.

[0052] This transparent display system includes the same structure and beneficial effects as the optical waveguide module 10 in the foregoing embodiment. The structure and beneficial effects of the optical waveguide module 10 have been described in detail in the foregoing embodiment and will not be repeated here.

[0053] The foregoing are only embodiments of the present application and are not intended to limit the protection scope of the present application. For those skilled in the art, various changes and modifications can be made to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. An optical waveguide module, characterized in that, Comprising: An optical waveguide body, on which an input grating region and an output grating region are formed. The output grating region forms a dual-channel grating. Incident light is perpendicularly incident on the optical waveguide body through the input grating region, and when passing through the dual-channel grating of the output grating region, it undergoes volume holographic diffraction and is divided into two deflected light beams for propagation. The two deflected light beams are perpendicularly emitted from the back surface of the output grating region respectively, and the two deflected light beams form a deflection angle of +a and -a with the optical axis respectively.

2. The optical waveguide module according to claim 1, wherein The dual-channel grating has a first channel and a second channel symmetrically arranged on both sides of the optical axis. The incident light undergoes volume holographic diffraction through the first channel and the second channel, and respectively forms two deflected light beams with deflection angles of +a and -a with the optical axis.

3. The optical waveguide module according to claim 2, wherein The output grating region and the input grating region are coplanarly arranged on one side in the thickness direction of the optical waveguide body, and the direction of the optical axis is perpendicular to the thickness direction of the optical waveguide body.

4. The optical waveguide module according to claim 1, wherein The two deflected light beams undergo volume holographic diffraction in the output grating region and are emitted from the back surface of the output grating region in a direction perpendicular to the optical waveguide body.

5. The optical waveguide module according to claim 1, characterized in that The incident angle of the incident light on the optical waveguide body is less than the total reflection angle of the optical waveguide body.

6. The optical waveguide module according to claim 1, wherein The optical waveguide body is a volume holographic optical waveguide, and the input grating region and the output grating region are volume holographic diffraction grating regions.

7. The optical waveguide module according to any one of claims 1 to 6, characterized in that, The material of the optical waveguide body includes tempered glass.

8. The optical waveguide module according to any one of claims 1 to 6, characterized in that, The materials of the input grating region and the output grating region include photopolymer.

9. A transparent display system, characterized in that, Comprising the optical waveguide module, the optical engine module, the host module, and the interactive operation module according to any one of claims 1 to 8, and the interactive operation module, the host module, and the optical engine module are connected in sequence.

10. The transparent display system according to claim 9, characterized in that, The optical engine module is correspondingly arranged in the input grating region of the optical waveguide module.

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