WO2024149226A1

WO2024149226A1 - Optical assembly, projection apparatus, and transportation means

Info

Publication number: WO2024149226A1
Application number: PCT/CN2024/071284
Authority: WO
Inventors: 赵东峰; 周鹏程; 陈兴宇; 童开年
Original assignee: 华为技术有限公司
Priority date: 2023-01-09
Filing date: 2024-01-09
Publication date: 2024-07-18
Also published as: CN118311771A

Abstract

An optical assembly, a projection apparatus, and transportation means, which relate to the field of projection, and can achieve the miniaturization of a head-up display (HUD) device and expand a visual range. The optical assembly comprises a substrate and an optical film, the optical film is attached to one side of the substrate, and projected light (R0) in an HUD system enters the substrate through a first region of the optical film, is propagated to a second region of the optical film through the substrate, and exits from the substrate through the second region. The area of the second region is greater than that of the first region, so that the effect of expanding the visual range can be achieved. By means of the substrate and the optical film attached to the substrate, a required optical path can be obtained, so that an image formed by the projected light (R0) can be observed by human eyes. The space occupied by the optical assembly is small, so that the miniaturization requirement for the HUD device can be met. Moreover, the area of the second region is greater than that of the first region, that is, the projected light (R0) exits through a larger area, so that the human eyes can obtain a larger visual region.

Description

Optical component, projection device and transportation tool

Technical Field

The present application relates to the field of projection, and in particular to an optical component, a projection device and a transportation tool.

Background technique

With the development of smart cars, optical display devices such as head-up display (HUD) are gradually used in various vehicles to enhance the driving experience. The current HUD implementation scheme is mainly a free-form surface scheme, which forms an enlarged virtual image through multiple free-form surfaces. As the demand for field of view and virtual image distance increases, the volume of HUD will increase, which will affect the loading and use on the vehicle. Therefore, miniaturization of HUD is an important requirement.

Summary of the invention

The present application provides an optical component, a projection device and a transportation tool, which can realize the miniaturization of the HUD.

In a first aspect, the present application provides an optical component for use in a head-up display (HUD) system, the optical component comprising a first substrate and a first optical film, the first optical film being bonded to one side of the first substrate, the first optical film comprising a first region and a second region, the area of the second region being larger than the area of the first region, the first region being used to receive projection light of the HUD system, the projection light being transmitted to the second region via the first substrate, and the projection light being emitted from the first substrate via the second region.

The first area can change the optical path of the projection light. When the projection light passes through the first area, the projection light is incident on the first substrate at a certain angle and propagates in the first substrate. When the projection light propagates to the second area, the second area changes the optical path of the projection light. For example, the projection light is reflected by the second area to change the optical path, so that the projection light is emitted from the first substrate. The desired optical path can be obtained by the substrate and the optical film bonded to the substrate, so that the image formed by the projection light can be observed by the human eye. The optical component occupies a small space and can meet the miniaturization requirements of the HUD. And the area of the second area is larger than that of the first area, that is, there is a larger area to emit the projection light, which can enable the human eye to obtain a larger range of visible area, that is, to achieve the function of pupil expansion and increase the eye box.

The way in which the first region changes the optical path of the projection light may be transmissive, i.e., entering the optical film from one side of the optical film and exiting the optical film from the other side of the optical film; or may be reflective, i.e., entering and exiting the optical film from the same side of the optical film. Similarly, the way in which the second region changes the projection light may be transmissive or reflective. The ways in which the first region and the second region change the projection light may be the same or different, and the present application does not impose any restrictions on this. The propagation mode of the projection light in the first substrate may be total reflection. Total reflection means that when light enters a medium with a higher refractive index into a medium with a lower refractive index, if the incident angle is greater than a certain critical angle, the refracted light will disappear, and all incident light will be reflected without entering the medium with a lower refractive index, which is not equivalent to no loss at all during the propagation process. In the process in which the projection light propagates by total reflection, due to errors and impurities in the medium, not all projection light is propagated by reflection. The total reflection is an ideal state.

In a possible implementation manner, the diffraction efficiency of at least one of the first region and the second region is gradually changed. During the propagation of the projection light in the first substrate, as the propagation path is extended, part of the projection light is emitted from the substrate, thereby causing loss, making the light intensity of the light emitted through the longer propagation path weaker than the light intensity of the light emitted through the shorter propagation path, thereby making the image brightness observed by the human eye uneven. By designing the diffraction efficiency of the first region and the second region, the brightness of the emitted light can be made uniform.

In a possible implementation manner, the diffraction efficiency of at least one of the first area and the second area gradually increases along the propagation direction of the projected light. Through the above design, the light that needs to be emitted through a longer propagation path obtains a higher diffraction efficiency, thereby increasing its light intensity when emitted, or the light that needs to be emitted through a shorter propagation path obtains a lower diffraction efficiency, thereby reducing its light intensity when emitted, so that the light intensity of the emitted light is the same or similar, so that the human eye observes an image with uniform brightness.

In a possible implementation manner, the first optical film includes a base film and a photosensitive layer, and the photosensitive layer is arranged in the first area and the second area, and is located between the base film and the first substrate. The base film is used to fix the photosensitive layer, and at the same time protects the photosensitive layer to prevent external forces and foreign objects such as dust from damaging the optical structure of the photosensitive layer. The photosensitive layer is used to form an optical structure, so that the first optical film has the function of processing the projection light in a desired manner. The photosensitive layer is arranged in the first area and the second area, so that the projection light is injected into or emitted from the first substrate as required. The light processing methods of different areas in the photosensitive layer can be the same or different. The photosensitive layer can transmit and reflect light, for example, the projection light is transmitted through the first area, and the projection light is reflected by the second area. The photosensitive layer is located between the base film and the first substrate, so that the first optical film and the substrate as a whole can obtain the desired optical properties. This structure also ensures that the photosensitive layer is not easily damaged by external forces.

In a possible implementation manner, the photosensitive layer includes a grating structure. The photosensitive layer has a grating structure, which is composed of a large number of flat An optical device composed of row slits is called a grating. Gratings are also divided into transmission gratings and reflection gratings. Gratings can diffract light beams. The grating structure in the photosensitive layer is used to change the optical path of the projection light, thereby causing the projection light to enter, exit, or propagate in the first substrate. Optionally, the grating structure is located in the first area and the second area, so that the projection light enters or exits the first substrate by diffraction.

In a possible implementation manner, the first optical film further includes a third region, and the third region is used to transmit the projection light from the first region to the second region via the third region, and the area of the third region is larger than the area of the first region and smaller than the area of the second region. After the projection light enters the first substrate via the first region, it passes through the third region, and the third region can change the optical path of the projection light, thereby obtaining the desired position and area of the second region. By adjusting the projection light through the third region, a larger area of the second region can be obtained, thereby achieving a better pupil expansion effect, obtaining a larger eye box, and obtaining a larger visual range.

In a possible implementation manner, the diffraction efficiency of the third region is gradually changed. Optionally, the diffraction efficiency of the third region gradually increases along the propagation direction of the projection light. During the propagation of the projection light in the first substrate, loss occurs as the propagation path lengthens, so that the light intensity of the light emitted through the longer propagation path is weaker than the light intensity of the light emitted through the shorter propagation path, thereby making the image brightness observed by the human eye uneven. By designing the diffraction efficiency of the third region, the brightness of the emitted light can be made uniform.

In a possible implementation manner, the pupil dilation amount of at least one of the first area, the second area, and the third area to the projection light is related to the projection area of the projection light in at least one of the first area, the second area, and the third area. By increasing the projection area of at least one of the first area, the second area, and the third area, the projection light has a larger visible range, a larger pupil dilation amount can be obtained, and ultimately a larger eye box and a larger visible range can be obtained.

In a possible implementation manner, the light intensities of the projection lights emitted from the first substrate are equal, or the difference between the light intensities of the projection lights emitted from the first substrate is lower than a first threshold value. By controlling the light intensities of the projection lights to be equal or the difference between the light intensities to be lower than the first threshold value when they are emitted, the uniformity of the brightness of the image observed by the human eye can be ensured, and a better visual effect can be obtained.

In a possible implementation, the optical component includes a multilayer structure, the first layer of the optical component includes the first substrate and the first optical film, the second layer of the optical component includes the second substrate and the second optical film, the second optical film is bonded to one side of the second substrate, and the first layer is disposed on one side of the second layer. The multilayer structure of the optical component can produce more optical path designs, for example, different layers can process projection light of different wavelength ranges respectively, so as to achieve higher efficiency and higher imaging brightness; for another example, different layers can be designed with different diffraction efficiencies respectively, so that the light intensity of the emitted light is uniform, thereby obtaining higher brightness uniformity; for another example, the visible range of the emitted light of each layer can be combined through the multilayer structure to obtain a larger visible range.

In a possible implementation manner, the second optical film includes a fourth region and a fifth region, the fourth region of the second optical film is used to receive the projection light emitted through the first region, and transmit the projection light to the fifth region through the second substrate, the projection light is emitted from the second substrate through the fifth region, and the area of the fifth region is larger than the area of the fourth region. The second optical film is used to process the projection light emitted through the first region, and can process the projection light together with the first layer. For example, different layers process projection light of different wavelength ranges respectively, and different layers have higher processing efficiency for projection light of different wavelength ranges, thereby achieving higher emission efficiency for the overall projection light and higher imaging brightness; for another example, different diffraction efficiencies are designed for different layers respectively, so that the light intensity of the emitted light is uniform, thereby obtaining better brightness uniformity; for another example, the visible range of the emitted light of each layer can be combined through a multi-layer structure to obtain a larger visible range.

In a possible implementation, the projections of the second area and the fifth area in the direction of emission of the projected light are connected. Connected means that, under the premise of ensuring that the projections of the two are not separated from each other, the area of the overlapping region of the two is minimized as much as possible. Separation of the projections of the two will split the visible area and reduce the user experience; if the overlapping area of the two is too large, on the one hand, it will reduce the visible range and waste the performance of the optical component; on the other hand, the overlap between the two will cause the light intensity of the emitted light in this area to be greater than that of other non-overlapping areas, making the image brightness uneven and affecting the use effect. The projections of the second area and the fifth area in the direction of emission of the projected light are arranged in a connected manner, which can maximize the use of their respective areas, maximize the visible range that can be achieved by the optical component, and help to ensure the uniformity of image brightness.

In a possible implementation, the first region is used to propagate the projection light of a first wavelength range to the second region via the first substrate, and is also used to propagate the projection light of a second wavelength range to the fourth region, and the projection light of the first wavelength range is emitted from the first substrate via the second region; the fourth region is used to receive the projection light of a second wavelength range emitted via the first region, and is used to propagate the projection light of the second wavelength range to the fifth region via the second substrate, and the projection light of the second wavelength range is emitted from the second substrate via the fifth region; the projections of the second region and the fifth region in the direction of projection light emission overlap. The optical structures in the first optical film and the second optical film can be designed to process the projection light of different wavelength ranges, the first layer processes the projection light of the first wavelength range, and propagates the projection light of the second wavelength range to the second layer, and the second layer processes the projection light of the first wavelength range. The second area and the fifth area are processed and emitted from the second area and the fifth area respectively. In this embodiment, the projection light of different wavelength ranges is processed by different layers, and the layer for processing a specific wavelength range can be specifically designed to have a higher efficiency for the projection light of the wavelength range, thereby improving the overall efficiency of the device and making the imaging brightness higher. The second area and the fifth area overlap in the projection direction of the projection light, and the projection lights processed separately can be remixed to form the projection light of the complete wavelength band, realizing color display and achieving better imaging effect.

In a possible implementation manner, the optical component further includes a third layer, and the third layer of the optical component includes a third substrate and a third optical film, the third optical film is bonded to one side of the third substrate, and the third layer is arranged on one side of the second layer. The optical component is arranged as a three-layer structure, so that each layer can separately process the red band spectrometry, green band spectrometry and blue band spectrometry of the projection light, and each layer has a high efficiency for the band it processes, which can achieve overall high efficiency of the device and improve imaging brightness. The projection light of the complete band can be obtained by remixing the three band spectrometry after separate processing, so as to realize color imaging. Dividing the projection light into three band spectrometry and processing them separately can simplify the control of the image generation unit in the HUD system used to generate the projection light, and can control the emission of each band of light separately, so as to make the color display of the imaging more accurate.

In a possible implementation, the projection light is linearly polarized light. In the propagation direction of the light, the light vector of the linearly polarized light only vibrates in a fixed direction. Since the trajectory of the endpoint of the light vector is a straight line, it is called linearly polarized light. The plane formed by the direction of the light vector and the propagation direction of the light is called the vibration plane. The optical properties of linearly polarized light are single, and its vibration plane is fixed and does not rotate. There are fewer uncertain factors. When designing an optical structure for linearly polarized light, it is not necessary to consider the change of its vibration plane, which can simplify the design work of the structure and reduce the design cost of the optical component. Linearly polarized light has optical properties that natural polarized light does not have. The optical structure in the optical component can achieve higher efficiency for linearly polarized light and enable the system to achieve better display effects. For example, the grating structure in the optical component has higher diffraction efficiency for linearly polarized light, and the projection light is linearly polarized light to obtain higher imaging brightness. The polarized light can be emitted by an image generation unit, or the light emitted by the image generation unit can be processed into linearly polarized light as the projection light.

In a possible implementation manner, at least one of the first substrate, the second substrate or the third substrate is flat glass. Flat glass has a high refractive index, low cost, and can realize the function of total reflection of light therein, and is preferably used as the first substrate, the second substrate or the third substrate.

In a second aspect, the present application provides a projection device, comprising the optical component described in any possible implementation of the first aspect, and further comprising an image generation unit for generating the projection light.

In a third aspect, the present application provides a vehicle, comprising the optical component described in any possible implementation of the first aspect or the projection device and projection medium described in the second aspect, wherein the projection medium is used to receive the projection light processed by the optical component or the projection light emitted by the projection device.

In a fourth aspect, the present application provides a method for manufacturing an optical component, comprising manufacturing the first optical film by laser exposure, and laminating the first optical film to one side of the first substrate.

In a fifth aspect, the present application provides a light propagation method, which is applied to the propagation of light in the optical component, including the projection light entering the first substrate through the first area, propagating to the second area through the first substrate, and being emitted from the first substrate through the second area.

Regarding the possible implementation methods corresponding to the second, third, fourth and fifth aspects and the effects brought about by them, please refer to the introduction of various implementation methods in the first aspect, which will not be repeated here.

The present application adopts an optical component composed of an optical film and a substrate. By designing the optical structure in the optical film to control the light path, the visible range of imaging is increased, and the miniaturization of the HUD device is achieved; and the area of the second region is larger than the area of the first region, that is, there is a larger area to emit the projected light, so that the human eye can obtain a larger visible area.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of HUD imaging;

FIG2 is a schematic diagram of a usage scenario of an optical component provided by the present application;

FIG3 is a schematic diagram of an optical component provided by the present application;

FIG4 is a schematic diagram of another optical component provided by the present application;

FIG5 is a schematic diagram of another optical component provided by the present application;

FIG6 is a schematic top view of an optical component provided by the present application;

FIG7 is a schematic diagram of an optical path of an optical component provided by the present application;

FIG8 is a schematic diagram of another optical component provided by the present application;

FIG9 is a schematic diagram of another optical component provided by the present application;

FIG10 is a schematic diagram of another optical component provided by the present application;

FIG11 is a schematic diagram of another optical component provided by the present application;

FIG12 is a schematic diagram of another optical component provided by the present application;

FIG13 is a schematic diagram of another optical component provided by the present application;

FIG14 is a schematic diagram of another optical component provided by the present application;

FIG15( a) is a schematic diagram of another optical component provided by the present application;

FIG15( b) is a schematic diagram of another optical component provided by the present application;

FIG16( a) is a schematic diagram of another optical component provided by the present application;

FIG16( b) is a schematic diagram of another optical component provided by the present application;

FIG. 17 is a schematic diagram of a usage scenario of the projection device provided in the present application.

Detailed ways

In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the embodiments of the present application will be further described in detail below with reference to the accompanying drawings.

For ease of understanding, the following examples provide some explanations of concepts related to the embodiments of the present application for reference. As described below:

1. Head-up Display (HUD)

Also known as the head-up display system, it is mainly used to display driving information such as speed navigation on the display device in front of the driver (such as the windshield), so as to reduce the driver's line of sight diversion time, avoid pupil changes caused by the driver's line of sight diversion, and improve driving safety and comfort.

The HUD mainly includes a picture generation unit (PGU) and an optical display system. The picture generation unit is used to generate the HUD output image, and the optical display system is used to display the image. The PGU mainly includes a light source and an optical unit. The light source is used to generate projection light. The projection light is projected to the optical element, and the image is formed by the optical element and projected to the optical display system. Optionally, the PGU may also include other optical elements for adjusting the optical characteristics or the emission path of the light beam.

2. Projection Light

In HUD, the light beam generated by the light source in the image generation unit and used to produce the image is called projection light.

3. Photosensitive layer

The photosensitive layer is used to form an optical structure, so that the light beam can be processed so that it propagates in the desired manner and optical path. The photosensitive layer is composed of materials whose structure or other physical parameters can change with light, including photopolymers, polymer dispersed liquid crystals and liquid crystal materials, and can be processed by laser exposure to obtain the desired optical structure.

4. Basement membrane

The base film is used to protect the photosensitive layer and the optical structure it forms, including triacetyl cellulose film (Triacetyl Cellulose, TAC), cyclic olefin copolymer film (Cyclic Olefin Copolymer, COC), polyester film (Polyester Film, PET), etc.

5. Substrate

The substrate is used to provide a total reflection path for the projected light, and its material includes resin or glass, etc. The shape is generally a flat plate, and can also be designed into other shapes as needed.

6. Diffraction

The phenomenon that light deviates from the straight-line propagation when encountering an obstacle in its propagation path is called diffraction of light.

7. Eye Box

The image projected by the HUD is reflected through the windshield to the driver's eye activity area. The range in which the driver's eyes can see the entire displayed image is called the eye box. The eye box size is an important parameter for evaluating HUD performance.

8. Pupil dilation

The process of changing the optical path and expanding the eye box by adding optical components, changing the properties of components, etc. is called pupil dilation.

9. Diffraction efficiency

Diffraction efficiency refers to the ratio of light intensity in a certain direction to the incident light intensity, which is called diffraction efficiency.

10. Linear polarized light

In the direction of light propagation, the light vector vibrates only in one fixed direction. This light is called linearly polarized light.

In the embodiments of the present application, the number of nouns, unless otherwise specified, means "singular noun or plural noun", that is, "one or more". "At least one" means one or more, and "plural" means two or more. "And/or" describes the association relationship of related objects, indicating that there can be three kinds of relationships. For example, A and/or B can mean: A exists alone, A and B exist at the same time, and B exists alone, where A and B can be singular or plural. Unless otherwise specified, the character "/" generally indicates that the related objects before and after are in an "or" relationship. For example, A/B means: A or B. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c means: a, b, c, a and b, a and c, b and c, or a and b and c, where a, b, and c can be single or multiple.

The ordinal numbers such as "first" and "second" mentioned in the embodiments of the present application are used to distinguish multiple objects, and are not used to limit the size, content, order, timing, application scenarios, priority or importance of multiple objects.

In the various embodiments of the present application, unless otherwise specified or provided for by logic, the terms and/or descriptions between the various embodiments are consistent and may be referenced to each other, and the technical features in different embodiments may be combined to form new embodiments according to their inherent logical relationships.

As described above, some concepts involved in the embodiments of the present application are introduced. The following describes the technical solutions of the embodiments of the present application.

Please refer to Figure 1, which is a schematic diagram of HUD imaging. The arrow line in the figure is a schematic diagram of the direction of light propagation. PGU is an image generation unit, M1, M2 and M3 are optical elements, M1 is a diffuser, M2 and M3 are two free-form surface optical elements, and F1 is a windshield. The image generated by PGU is reflected onto the windshield through the optical element. When the driver looks out of the car through the windshield, he can see the virtual image projected on the windshield by the HUD system. The virtual image content may include road instructions, mileage, speed information, navigation information, audio and video entertainment system information, etc., so that the driver can understand the required information without diverting his eyes when driving the vehicle, avoiding driving risks caused by the driver not being able to take into account the road conditions due to diverting his eyes. The solution of enlarging the image and adjusting the optical path through two or more free-form surfaces will increase the volume of the HUD with the increase of the required field of view and virtual image distance. For example, the real-focus image generated by the PGU needs to be magnified more than 100 times as the field of view (FOV) and virtual image distance (VID). As the demand for field of view (FOV) and virtual image distance (VID) increases, the volume of the solution will increase dramatically. For example, when the FOV is 15*5 degrees and the VID is 7.5 meters, the volume of the HUD reaches 15 liters, and when the FOV is 20*8 degrees and the VID is 20 meters, the volume of the HUD reaches 25 liters, which is difficult to install and use on the vehicle. For this purpose, the solution described in this application is provided.

The embodiment of the present application provides an optical component for use in a head-up display system, wherein the optical component includes: a first substrate and a first optical film, wherein the first optical film is bonded to one side of the first substrate, wherein the first optical film includes a first area and a second area, wherein the first area is used to receive the projection light of the HUD system, and transmit the projection light to the second area via the first substrate, wherein the projection light is emitted from the first substrate via the second area, and wherein the area of the second area is larger than the area of the first area. Through the substrate and the optical film bonded to the substrate, the desired optical path can be obtained, so that the image formed by the projection light can be observed by the human eye. The optical component occupies a small space and can meet the miniaturization requirements of the HUD. Moreover, the area of the second area is larger than that of the first area, i.e., there is a larger area to emit the projection light, so that the human eye can obtain a larger range of visible area, i.e., the function of pupil expansion is realized and the eye box is enlarged.

Please refer to Figure 2, which is a schematic diagram of a usage scenario of the optical component provided in the present application. The arrow line in the figure is a schematic diagram of light propagation. The optical component is used to change the light path so that the projected light emitted by the PGU enters the driver's eyes through the windshield.

Specifically, please refer to FIG3 , in which the arrow line indicates the optical path of the projection light. The projection light enters the first substrate through the first area, propagates in the first substrate by total reflection, and then exits from the first substrate through the second area. Total reflection refers to the phenomenon that when light enters a medium with a higher refractive index from a medium with a lower refractive index, if the incident angle is greater than a certain critical angle, the refracted light will disappear, and all incident light will be reflected without entering the medium with a low refractive index. This is not equivalent to no loss at all during the propagation process. In the process of the projection light propagating by total reflection, due to errors and impurities in the medium, not all projection light is propagated by reflection. The total reflection is an ideal state.

The refractive index of the first substrate is higher than that of the first optical film and the surrounding medium, such as air, and when the projection light is incident at an appropriate angle, it propagates therein by total reflection. Optionally, the first substrate is flat glass. Optionally, the material of the first substrate can be resin, polymer material, inorganic glass, organic glass, crystal, etc., which can be used to achieve total reflection. In the process of the projection light propagating by total reflection, due to errors and impurities in the medium, not all projection light is propagated by reflection, and the total reflection is an ideal state. The substrate can be a variety of shapes such as rectangle, circle, ellipse, irregular polygon, etc., and the present application does not impose any restrictions on this. The substrate can be a waveguide type optical element.

The first optical film and the first substrate may be bonded together, and after the projection light passes through the first region, for example, after transmitting through the first region, its optical path changes and the projection light directly enters the first substrate.

There may be other structures between the first optical film and the first substrate, such as an anti-reflection film, an adhesive layer, etc., which do not affect the structure of the projected light entering the first substrate.

The first optical film may be continuous or discontinuous in space. Please refer to FIG3, which is a schematic diagram of an optical component provided by the present application, wherein the first optical film is continuous in space; please refer to FIG4, which is a schematic diagram of another optical component provided by the present application, wherein the first area is used to transmit the projection light into the substrate, and the second area can reflect the projection light so that the projection light is emitted from the substrate, wherein The first optical film is spatially discontinuous and also includes the first region and the second region. The first region and the second region may also act on the projection light through other optical principles, so that the projection light is emitted from the substrate. The optical film may be a holographic optical element (HOE).

According to the optical properties of the second area and the optical properties of the first substrate, including whether the way of changing the optical path is transmissive or reflective, there are multiple directions in which the projection light is emitted from the substrate. Please refer to Figure 5, which is a schematic diagram of an optical component provided by the present application. The arrow line in the figure is the projection light, and the dotted arrow is the direction in which the projection light may be emitted or emitted. According to the optical properties of the first area or the second area and the first substrate, the projection light may be emitted or injected from one side of the first optical film of the first substrate, or may be emitted or injected from the other side. Taking the first area as an example, if the first area is a transmissive grating, in order to make the projection light enter the first substrate through the first area, the incident direction must be on the side of the first optical film; if the first area is a reflective grating, the incident direction must be on the side of the substrate. Similarly, the second area is the same. After the projection light enters the substrate, the first area changes its optical path so that it cannot be emitted from the substrate, so it propagates in the substrate in a total reflection manner; when it passes through the second area, the optical path is changed again so that it no longer meets the total reflection condition, and then it is emitted from the first substrate. Due to the wear and error caused by the first optical film and the first substrate during production, manufacturing and use, the emission or incident direction of the projection light may not be perpendicular to the plane of the first substrate, resulting in deviation. The projection light can be emitted from the first substrate if the emission angle meets the emission conditions of the current design. The emission direction shown in FIG5 is only an example to illustrate the possibility of the emission direction and is not a limitation on the emission direction.

Optionally, please refer to Figure 6, which is a top view schematic diagram of an optical component provided in the present application, and exemplarily gives the relative position relationship between the first area and the second area. The relative position of the second area and the first area can be designed as needed. The area of the second area is larger than that of the first area as long as the desired pupil expansion effect can be achieved. The present application does not impose any restrictions on this.

The optical component adjusts the optical path of the projection light through the first optical film and the first substrate, and realizes the pupil expansion effect. The projection light adjusts the optical path in the optical component, and the required space volume is small, which is conducive to the miniaturized design of the HUD.

In a possible implementation manner, the diffraction efficiency of at least one of the first region and the second region is gradually changing. Optionally, the diffraction efficiency of at least one of the first region and the second region gradually increases along the propagation direction of the projection light. Please refer to Figure 7, which is a schematic diagram of the light path of an optical component provided in the present application. After the projection light R0 is diffracted for the first time, part of the projection light R1 is emitted from the first substrate, and the remaining part of the projection light R2 continues to propagate in the first substrate. Since part of the projection light R1 is emitted, the light intensity of the projection light R2 is weaker than that of the projection light R0; when the projection light R2 passes through the second region again, part of the projection light R3 is emitted from the first substrate. If the diffraction efficiency of the second region is uniform, the light intensity of the projection light R3 is weaker than that of the projection light R1; the remaining part of the projection light R4 continues to propagate, and the projection light R5 is emitted from the first substrate. Similarly, the light intensity of the projection light R5 is weaker than that of the projection light R3. Therefore, the brightness of the image observed by the human eye is uneven. If the diffraction efficiency of the second region gradually increases along the propagation direction of the projected light, as shown in FIG7 , the diffraction efficiency of the second region gradually increases from R1 to R3. For example, the diffraction efficiency of the second region at R1 is 0.2. Assuming that the light intensity of R0 is calculated as 100, the light intensity of R1 is 20, and the light intensity of R2 is 80. If the diffraction efficiency of the second region at R3 is 0.25, the light intensity of R3 is 80×0.25=20, which is equal to R1. Similarly, the diffraction efficiency at R5 is 1/3, and the light intensity of R5 is 20, which is the same as R1 and R3, so that the brightness of the image can be uniform. The above light intensity data is only for explaining the principle and should not be understood as limiting the scheme.

In a possible implementation manner, the first optical film includes a base film and a photosensitive layer, and the photosensitive layer is arranged in the first area and the second area, and is located between the base film and the first substrate. Please refer to Figure 8, which is a schematic diagram of an optical component provided in the present application. Optionally, the photosensitive layer is arranged in the first area and the second area, and is used to form an optical structure to change the optical path of the projection light. Optionally, the photosensitive layer includes a grating structure. Optionally, the grating structure includes the first area and the second area. The grating structure formed by the photosensitive layer in the first area and the second area can change the optical path of the projection light, so that the projection light is incident on or emitted from the first substrate, or propagates in the first substrate. The photosensitive layer is arranged in the first area and the second area, and is located between the base film and the first substrate. The base film is used to fix the photosensitive layer, and at the same time protect the photosensitive layer to prevent external forces from damaging the optical structure of the photosensitive layer.

In a possible implementation manner, the first optical film further includes a third region, and the third region is used to transmit the projection light from the first region to the second region via the third region, and the area of the third region is larger than the area of the first region and smaller than the area of the second region. Please refer to FIG9, which is a schematic diagram of an optical component provided in the present application. The third region can further adjust the light path, and the projection light can change the position of the second region through the third region to make the best use of the area of the optical component, and can also obtain a larger area of the second region through the third region to improve the pupil expansion effect of the optical component. There may be various positional relationships among the first region, the second region, and the third region, which can be arranged and designed as needed, and the present application does not impose any restrictions on this. For example, please refer to FIG10, which is a schematic diagram of an optical component provided in the present application. The area of the third region is larger than the area of the first region and smaller than the area of the second region, and the area of the region can be effectively utilized. Because the second region needs to achieve a pupil expansion effect, the projection light first passes through the third region. The projection light passes through the second area, and the projection light projects an area in the second area that is larger than the projection light projected in the third area. Optionally, the area and position relationship of the first area, the second area, and the third area may also have other combinations, for example, the area of the second area is equal to the area of the third area, and both are larger than the area of the first area.

In a possible implementation manner, the diffraction efficiency of the third area is gradual. Optionally, the diffraction efficiency of at least one of the first area and the second area gradually increases along the propagation direction of the projected light. By changing the diffraction efficiency of at least one of the first area, the second area, and the third area so that it gradually changes along the propagation direction of the projected light, the effect of uniform output light intensity can be achieved. Optionally, the light intensity of the projected light emitted from the first substrate is equal, or the difference between the light intensity of the projected light emitted from the first substrate is lower than a first threshold. When the light intensity is equal, the brightness of the image formed is uniform, which is the ideal situation to be achieved. The first threshold can be set according to needs, for example, the relative difference between the light intensity is less than 10%, or the absolute difference is less than 10cd. Optionally, the first threshold can also be set to other values to meet the needs, and those skilled in the art can expand it as needed. This application is not limited to this, and the scope of protection is subject to the claims.

In a possible implementation, the pupil dilation amount of at least one of the first area, the second area, and the third area for the projection light is related to the projection area of the projection light in at least one of the first area, the second area, and the third area. Please refer to Figure 11, which is a schematic diagram of the optical component provided by the present application. Among them, C1 is the area of the projection light projected on the first area, C3 is the area of the projection light projected on the third area, and C2 is the area of the projection light projected on the second area. The larger the projection area of the projection light, the greater the pupil dilation achieved in the corresponding area, the larger the range of the image that can be observed when the first substrate is finally emitted, and the larger the range of the eye box formed.

In a possible implementation manner, the optical component includes a multilayer structure, the first layer of the optical component includes the first substrate and the first optical film, the second layer of the optical component includes a second substrate and a second optical film, the second optical film is laminated to one side of the second substrate, and the first layer is disposed on one side of the second layer. The properties of the second optical film are the same as those of the first optical film, and are not described in detail here.

Please refer to Figure 12, which is a schematic diagram of an optical component provided by the present application. The multilayer structure of the optical component can produce more light path designs, thereby obtaining higher brightness uniformity and a larger eye box range. The multilayer structure can also be used to design each single-layer structure so that it has higher efficiency for the portion of the projection light that needs to be processed, thereby improving the overall efficiency of the HUD. Optionally, please refer to Figure 13, which is a schematic diagram of an optical component provided by the present application. The arrangement of the multilayer structure can also be as shown in Figure 13, where the first substrate is adjacent to the second substrate, and the optional positional relationship between the optical film and the substrate can be multiple, for example, the optical film is located above the substrate, and for another example, the optical film is located below the substrate. Optionally, the multilayer structure can also be three, four or more layers. Optionally, the adjacent relationship between the layers and the positional relationship between the optical films of different layers and the substrate can be determined as needed, and the present application does not limit this. The number and positional relationship of the regions included in the optical films on different layers are not limited. For example, in the first layer, the first optical film includes two regions, the first region, the second region and the third region. In the second layer, the second optical film includes the fourth region and the fifth region.

For a possible implementation, please refer to FIG. 14, which is a schematic diagram of an optical component provided by the present application. The second optical film includes a fourth area and a fifth area, and the fourth area of the second optical film is used to receive the projection light emitted through the first area, and transmit the projection light to the fifth area through the second substrate, and the projection light is emitted from the second substrate through the fifth area, and the area of the fifth area is larger than the area of the fourth area. The second optical film is used to process the projection light emitted through the first area, and can process the projection light together with the first layer. The optical structures of the second layer structure and the first layer structure are designed respectively, and each layer has a higher efficiency for the wavelength band it processes, so that it can efficiently process part of the projection light respectively, so that the final imaging brightness is higher. The first region is used to propagate the projection light of the first wavelength range to the second region via the first substrate, and is also used to propagate the projection light of the second wavelength range to the fourth region, and the projection light of the first wavelength range is emitted from the first substrate via the second region; the fourth region is used to receive the projection light of the second wavelength range emitted via the first region, and is used to propagate the projection light of the second wavelength range to the fifth region via the second substrate, and the projection light of the second wavelength range is emitted from the second substrate via the fifth region; the projections of the second region and the fifth region in the direction of projection light emission overlap. Please refer to Figure 14, the projection light L1 is the projection light of the wavelength in the first range, which is processed by the first layer, and the projection light L2 is the projection light of the wavelength in the second range, which is processed by the second layer. The projections of the second region and the fifth region in the direction of projection light emission overlap, and the projection lights processed separately can be remixed to form the projection light of the complete wavelength band, so as to realize color display and achieve better imaging effect. In Figure 14, in order to clearly express the light path, L1 and L2 are not drawn to overlap, and it should be understood that the light paths of L1 and L2 can overlap when they are emitted. Optionally, L1 is the projection light of the blue band, and L2 is the projection light of the other bands.

In a possible implementation manner, the projections of the second area and the fifth area in the direction of the projection light emission are connected. Please refer to FIG. 15( a ), which is a schematic diagram of an optical component provided by the present application. Through the two-layer structure, different layers can be designed to have different diffraction efficiency, so that the light intensity of the emitted light is uniform, thereby obtaining a higher brightness uniformity; for another example, the visible range of the emitted light of each layer can be combined through a two-layer structure to obtain a larger visible range. Connection means that, under the premise of ensuring that the projections of the two are not separated from each other, the area of the overlapping area of the two is minimized as much as possible. The separation of the projections of the two will split the visible area and reduce the user experience; if the overlapping area of the two is too large, on the one hand, the visible range is reduced and the performance of the optical component is wasted, on the other hand, the overlap between the two will cause the light intensity of the emitted light in this area to be greater than that of other non-overlapping areas, making the image brightness uneven and affecting the use effect. The projections of the second area and the fifth area in the direction of the projection light emission are arranged in a connected manner, which can maximize the use of their respective areas, maximize the visible range that can be achieved by the optical component, and help to ensure the uniformity of the image brightness. Different from the wavelength division multiplexing method, this implementation method is space division multiplexing. Please refer to Figure 15 (b), which is the multi-layer structure, in the direction of the projection light emission, the projections of the second area and the fifth area are connected.

For a possible implementation, please refer to FIG. 16( a ), which is a schematic diagram of an optical component provided by the present application. The optical component further includes a third layer, the third layer of the optical component includes a third substrate and a third optical film, the third optical film is laminated on one side of the third substrate, and the third layer is disposed on one side of the second layer.

The structure and characteristics of the third layer are the same as those of the first layer, and will not be described again here.

Optionally, the three-layer structure can realize that each layer can process the red band light spectrum L3, green band light spectrum L2 and blue band light spectrum L1 of the projection light separately, and each layer has a high efficiency for the band it processes, which can realize the overall high efficiency of the device and improve the imaging brightness. After the three band light spectrums are processed separately and then remixed, the projection light of the complete band can be obtained to realize color imaging. Dividing the projection light into three band light spectrums and processing them separately can simplify the control of the image generation unit in the HUD system used to generate the projection light, and the emission of each band light can be controlled separately, so that the color display of the imaging is more accurate. It should be understood that in order to make the light path clear, the three-layer structure in the figure is a separation diagram, and the three-layer structure can be bonded to each other, and can also include auxiliary structures such as anti-reflection film and bonding layer, which do not affect the light path. Please refer to Figure 16 (b), which is a top view of the optical component of the three-layer structure, in which the regions of the light emitting from each layer, such as the second region, the fifth region and the seventh region, overlap in the projection direction of the projection light.

Optionally, the projection light is linearly polarized light. The optical properties of linearly polarized light are single and have fewer uncertainties. Designing an optical structure for linearly polarized light can simplify the design of the structure and reduce the design cost of the optical component. Linearly polarized light has optical properties that natural polarized light does not have. The optical structure in the optical component can achieve higher efficiency for linearly polarized light, allowing the system to achieve better display effects. For example, the grating structure in the optical component has higher diffraction efficiency for linearly polarized light, and the projection light is linearly polarized light to obtain higher imaging brightness. The polarized light can be emitted by an image generation unit, or the light emitted by the image generation unit can be processed into linearly polarized light as the projection light.

Optionally, at least one of the first substrate, the second substrate or the third substrate is flat glass. Flat glass has a high refractive index, low cost, and can realize the function of total reflection of light therein, and is preferably used as the first substrate, the second substrate or the third substrate.

The present application also provides a projection device. Please refer to FIG17, which is a schematic diagram of the use scenario of the projection device provided by the present application. The projection device is applied to HUD, and the HUD includes a combined head-up display device (combiner HUD, C-HUD), a windshield head-up display device (windshield-HUD, W-HUD) and an augmented reality head-up display device (augmented reality HUD, AR-HUD) and other devices or functional units that can realize the head-up display function.

The present application also provides a means of transport, please refer to Figure 17. The figure shows the means of transport, the vehicle, and the car windshield as the projection medium. Of course, the projection medium can also be other devices, which are not limited here. It is used to receive the projection light processed by the optical component or the projection light emitted by the projection device. The vehicle described in the present application can be a traditional fuel vehicle, or it can be a new energy vehicle such as a pure electric vehicle or a hybrid vehicle. It can be any of the different types of vehicles such as a sedan, a truck, a passenger bus, a sport utility vehicle (SUV), etc. It can also be a land transportation device for carrying people or goods such as a tricycle, a motorcycle, and a train. Alternatively, the projection device of the present application can also be used in other types of transportation vehicles such as airplanes and ships.

The above is only a specific implementation of the embodiment of the present application, but the protection scope of the embodiment of the present application is not limited thereto, and any changes or replacements within the technical scope disclosed in the present application should be included in the protection scope of the embodiment of the present application. Therefore, the protection scope of the embodiment of the present application should be based on the protection scope of the claims.

Claims

An optical component, used in a head-up display (HUD) system, characterized in that the optical component comprises:

A first substrate and a first optical film, wherein the first optical film is bonded to one side of the first substrate, the first optical film includes a first area and a second area, the first area is used to receive projection light of the HUD system, the projection light is transmitted to the second area via the first substrate, the projection light is emitted from the first substrate via the second area, and the area of the second area is larger than that of the first area.
The optical component according to claim 1, characterized in that the diffraction efficiency of at least one of the first region and the second region is gradually changed.
The optical component according to claim 1 or 2 is characterized in that the diffraction efficiency of at least one of the first area and the second area gradually increases along the propagation direction of the projected light.
The optical component according to any one of claims 1 to 3, characterized in that the first optical film comprises a base film and a photosensitive layer, and the photosensitive layer is arranged in the first area and the second area and is located between the base film and the first substrate.
The optical component according to claim 4, characterized in that the photosensitive layer includes a grating structure.
The optical component according to any one of claims 1-5 is characterized in that the first optical film also includes a third area, the third area is used to transmit the projection light from the first area to the second area via the third area, and the area of the third area is larger than the area of the first area and smaller than the area of the second area.
The optical component according to claim 6, characterized in that the diffraction efficiency of the third region is gradually varied.
The optical component according to claim 6 or 7 is characterized in that the diffraction efficiency of the third region gradually increases along the propagation direction of the projected light.
The optical component according to any one of claims 6 to 8, characterized in that at least one of the first area, the second area, and the third area is used to expand the pupil of the projection light.
The optical component according to any one of claims 6 to 9 is characterized in that the pupil expansion amount of at least one of the first area, the second area, and the third area to the projection light is related to the projection area of the projection light in at least one of the first area, the second area, and the third area.
The optical component according to any one of claims 1-10 is characterized in that the light intensities of the projection lights emitted from the first substrates are equal, or the difference between the light intensities of the projection lights emitted from the first substrates is lower than a first threshold.
The optical component according to any one of claims 1 to 11 is characterized in that the optical component includes a multilayer structure, the first layer of the optical component includes the first substrate and the first optical film, the second layer of the optical component includes a second substrate and a second optical film, the second optical film is bonded to one side of the second substrate, and the first layer is arranged on one side of the second layer.
The optical component according to claim 12 is characterized in that the second optical film includes a fourth area and a fifth area, the fourth area of the second optical film is used to receive the projection light emitted through the first area, and transmit the projection light to the fifth area through the second substrate, the projection light is emitted from the second substrate through the fifth area, and the area of the fifth area is larger than the area of the fourth area.
The optical component according to claim 12 or 13, characterized in that the projections of the second area and the fifth area in the direction of emission of the projection light are connected.
The optical component according to any one of claims 12-13 is characterized in that the first region is used to propagate the projection light of the first wavelength range to the second region via the first substrate, and is also used to propagate the projection light of the second wavelength range to the fourth region, and the projection light of the first wavelength range is emitted from the first substrate via the second region; the fourth region is used to receive the projection light of the second wavelength range emitted via the first region, and is used to propagate the projection light of the second wavelength range to the fifth region via the second substrate, and the projection light of the second wavelength range is emitted from the second substrate via the fifth region; the projections of the second region and the fifth region in the direction of projection light emission overlap.
The optical component according to any one of claims 12 to 15 is characterized in that the optical component also includes a third layer, the third layer of the optical component includes a third substrate and a third optical film, the third optical film is bonded to one side of the third substrate, and the third layer is arranged on one side of the second layer.
The optical component according to any one of claims 1-16, characterized in that the projection light is linearly polarized light.
The optical component according to any one of claims 1-17, characterized in that at least one of the first substrate, the second substrate or the third substrate is flat glass.
A projection device, characterized in that it comprises the optical component and an image generating unit according to any one of claims 1 to 18, wherein the image generating unit is used to generate the projection light.
A means of transport, characterized in that it comprises the optical component described in any one of claims 1 to 18 or the projection device described in claim 19, and also comprises a projection medium, wherein the projection medium is used to receive the projection light processed by the optical component or the projection light emitted by the projection device.