Optical film and head-up display device

Abstract

The application discloses an optical film and a head-up display device. The optical film comprises a substrate and a plurality of first microstructures in the substrate. The light transmittance of the substrate is less than that of the first microstructures. The substrate comprises a first surface and a second surface arranged oppositely. The first microstructures extend along a first direction and are periodically arranged along a second direction. The first microstructures are first isosceles triangles in a first cross section. The base of the first isosceles triangle is located on the first surface. An incident light transmission channel or an outgoing light transmission channel is formed between two adjacent first microstructures. The first direction intersects the second direction. The first cross section is perpendicular to the first direction. The optical film is attached to a projection substrate of the head-up display device, can realize high reflection of only the light rays of information to be conveyed emitted by the display module, low reflection of ambient light of other angles, and thus improves display contrast and visual effect.

Description

Technical Field

[0001] The present invention relates to the field of display technology, and more particularly to an optical film and a head-up display device. Background Technology

[0002] Currently, existing automotive head-up displays (HUDs) project light onto the viewer's eyes by reflecting it through a projection substrate (such as a windshield or a separately installed reflective substrate). This method requires the projection substrate to have high light reflectivity, so that as much light as possible is reflected from the display to the viewer's eyes. However, a highly reflective projection substrate also results in high reflection of ambient light, causing ambient light to interfere with the visual effect of the HUD information being conveyed, leading to a decrease in display contrast and affecting the HUD display quality. Summary of the Invention

[0003] Based on this, the present invention provides an optical film and a head-up display device. When the optical film is attached to the projection substrate of the head-up display device, it can achieve high reflection of light that is intended to convey information only at a specific angle emitted by the display module, while having low reflection of ambient light at other angles, thereby improving display contrast and visual effect.

[0004] In a first aspect, the present invention provides an optical film comprising:

[0005] The substrate includes a first surface and a second surface disposed opposite to each other.

[0006] Multiple first microstructures are located within the substrate. The first microstructures extend along a first direction and are periodically arranged along a second direction. The orthographic projection of the first microstructure on the first cross section is a first isosceles triangle, with the base of the first isosceles triangle located on the first surface. Adjacent first microstructures form an incident light transmission channel or an outgoing light transmission channel. The first direction intersects the second direction, and the first cross section is perpendicular to the first direction. The light transmittance of the substrate is less than that of the first microstructure.

[0007] In a second aspect, the present invention provides a head-up display device, including an image generating unit, a projection substrate, and an optical film provided in the first aspect, the optical film being disposed on the side of the projection substrate close to the image generating unit.

[0008] The optical film for head-up display devices provided by this invention includes a substrate and a plurality of first microstructures located within the substrate. The light transmittance of the substrate is less than that of the first microstructures. The substrate includes a first surface and a second surface disposed opposite to each other. The first microstructures extend along a first direction and are periodically arranged along a second direction. The orthographic projection of the first microstructure in a first cross section is a first isosceles triangle, and the base of the first isosceles triangle is located on the first surface. An incident light transmission channel or an outgoing light transmission channel is formed between two adjacent first microstructures. This proposal achieves high reflection of light emitted from a specific angle by attaching an optical film with a special structure to the projection substrate of the head-up display device. This allows for high reflection of light emitted from a specific angle by the display module to convey information, while reducing reflection of ambient light from other angles, thereby improving display contrast and visual effect. Attached Figure Description

[0009] Figure 1 This is a schematic diagram of an optical film applied to a head-up display device according to this application;

[0010] Figure 2 This is a top view schematic diagram of an optical film provided in this application;

[0011] Figure 3 yes Figure 1 A schematic cross-sectional view of an optical film along the AA' direction;

[0012] Figure 4 This is a top view schematic diagram of another optical film provided in this application;

[0013] Figure 5 yes Figure 4 A schematic cross-sectional view of an optical film along the BB' direction;

[0014] Figure 6 yes Figure 1 A schematic diagram of a cross-section of another optical film along the AA' direction;

[0015] Figure 7 yes Figure 4 A schematic diagram of a cross-section of another type of optical film along the BB' direction;

[0016] Figure 8 This is a top view schematic diagram of another optical film provided in this application;

[0017] Figure 9 This is a top view schematic diagram of another optical film provided in this application;

[0018] Figure 10 This is a top view schematic diagram of another optical film provided in this application;

[0019] Figure 11This is a top view schematic diagram of another optical film provided in this application;

[0020] Figure 12 This is a schematic diagram of another head-up display device provided in this application;

[0021] Figure 13 This is a structural schematic diagram of a head-up display device applied in an automobile, as provided in this application. Detailed Implementation

[0022] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0023] Based on one or more of the above-mentioned technical problems, embodiments of the present invention provide an optical film suitable for head-up displays. Figure 1 This is a schematic diagram of an optical film applied in a head-up display device, as provided in this application. Figure 2 This is a top view schematic diagram of an optical film provided in this application. Figure 3 yes Figure 1 A schematic cross-sectional view of an optical film along the AA' direction, for reference. Figures 1-3 This application provides an optical film 20 comprising a substrate 21 and a plurality of first microstructures 22 located within the substrate 21. The light transmittance of the substrate 21 is less than the light transmittance of the first microstructures 22. In specific implementations, the substrate 21 can be made of a transparent material, and the first microstructures 22 can be made of an opaque material. The substrate 21 includes a first surface M1 and a second surface M2 disposed opposite to each other. The first microstructures 22 extend along a first direction X and are periodically arranged along a second direction Y. The orthographic projection of the first microstructure 22 on a first cross-section is a first isosceles triangle, the base of which is located on the first surface M1. Adjacent first microstructures 22 form an incident light transmission channel or an outgoing light transmission channel. The first direction X intersects the second direction Y. The first cross-section (referring to the first surface M1) is a first isosceles triangle. Figure 3 The cross-section on the ZY plane is perpendicular to the first direction X. Here, the first cross-section refers to the first microstructure 22 in... Figure 3 The cross section on the ZY plane.

[0024] refer to Figure 1The optical film 20 provided in this embodiment can be attached to the side of the projection substrate 30 in the head-up display (HUD) facing the image generation unit (PGU) 10. The HUD can be a windshield-type head-up display (W-HUD), an augmented reality head-up display (AR-HUD), or the like. The image generation unit 10 is configured to output image light for the HUD, and can be a liquid crystal display panel, an organic or inorganic light-emitting display panel, or a projector, to provide a virtual image. In automotive applications, the displayed content can include dashboard information, navigation information, lane indicators, construction signs, accident signs, and pedestrian detection signs.

[0025] For details, please refer to Figures 2-4 The substrate 21 can be made of a material with high light transmittance, such as epoxy resin or acrylic resin. Multiple first microstructures 22 with low light transmittance are disposed within the substrate 21, which have the function of blocking or absorbing light. The material of the first microstructures 22 can be black, such as carbon black or pigment-based materials. That is, the light from the image output by the image generation unit 10 for the head-up display can pass through the substrate 21, but cannot pass through the first microstructures 22. The structure and arrangement of the first microstructures 22 are as follows:

[0026] First microstructure 22 along Figure 2 Extending in the X direction, along Figure 2 Periodically arranged in the Y direction. The first microstructure 22 is located in the first cross section ( Figure 3 The orthographic projection of the ZY section is a first isosceles triangle, with its base located on the first surface M1. Adjacent first microstructures 22 form either an incident light transmission channel or an outgoing light transmission channel, thus creating a periodically arranged light-absorbing structure. For example, when light ray S' reaches the first microstructure 22, it is blocked or absorbed.

[0027] The incident light transmission channel and the outgoing light transmission channel refer to the substrate 21 region between two adjacent first microstructures 22, which is transmissive to light. For different types of light, the substrate 21 region between two adjacent first microstructures 22 can be referred to as either the incident light transmission channel or the outgoing light transmission channel. For example, Figure 3 Region a in the middle is both the incident light transmission channel of the first ray a1 and the outgoing light transmission channel of the second ray a2.

[0028] Combination Figure 1 and Figure 3In a head-up display (HUD) application, the first portion of light S1 is the image light output by the image generation unit 10, and the second portion of light S2 is the ambient light. The first portion of light S1, after incident on the first surface M1, enters the substrate 21, passes through the incident light transmission channel into the substrate 21, is reflected by the second surface M2, and is output to the outside of the optical film 20 through the outgoing light transmission channel, reaching the user's viewing range to form a virtual image. The second portion of light S2, after incident on the first surface M1, enters the substrate 21, and at least a portion of the second portion of light S2 is blocked and absorbed by the first microstructure 22, preventing its emission. Therefore, the optical film 20 provided in this embodiment can transmit the first portion of light S1 at a specific angle while blocking and absorbing at least a portion of the second portion of light S2. When applied in a HUD display device, it can reduce ambient light brightness, improve display contrast, and optimize the visual effect of virtual image imaging.

[0029] In summary, the optical film provided in this application embodiment can reflect light highly at specific angles and reflect less light that is not needed. In head-up display applications, it can be attached to the surface of the projection substrate to achieve high reflection only for the light that the display module wants to convey information at a specific angle, while reflecting less ambient light at other angles, thereby improving display contrast and visual effect.

[0030] Based on the above embodiments, continue to refer to Figure 3 The incident angle Δ1 of the first ray S1 is greater than or equal to the first incident angle θ1 and less than or equal to the second incident angle θ2, i.e., θ1 ≤ Δ1 ≤ θ2. The incident angle Δ2 of the second ray S2 is less than the first incident angle θ1 or greater than the second incident angle θ2, i.e., Δ2 < θ1 or Δ2 > θ2. Here, the incident angle is the angle between the ray incident on the first surface M1 and the normal perpendicular to the first surface M1.

[0031] This can also be understood as follows: the first incident angle θ1 is the minimum incident angle of the first portion of light S1 that the user needs to observe, and the second incident angle θ2 is the maximum incident angle of the first portion of light S1 that the user needs to observe. In this embodiment, the structure of the first microstructure 22 can be adjusted so that the first portion of light S1 with incident angle Δ1 can pass through the incident light transmission channel to the second surface M2, be reflected by the second surface M2, and then exit from the first surface M1 through the outgoing light transmission channel. Simultaneously, the second portion of light S2 with incident angle Δ2 is blocked and absorbed, preventing it from exiting from the first surface M1.

[0032] Optionally, θ1 = 10°, θ2 = 30°, the incident angle Δ1 of the first part of the ray S1 is greater than or equal to 10° and less than or equal to 30°, that is, the value range of Δ1 is 10° to 30°, and the incident angle of the second part of the ray S2 is less than 10° or greater than 30°, that is, the value range of Δ2 is less than 10° or greater than 30°.

[0033] It should be noted that the angles θ1 and θ2 can also be reasonably adjusted according to the actual application needs, and this application embodiment does not impose specific limitations.

[0034] Figure 4 This is a top view schematic diagram of another optical film provided in this application. Figure 5 yes Figure 4 A cross-sectional schematic diagram of an optical film along the BB' direction, based on the above embodiment, with reference to... Figure 4 and Figure 5 The optical film 20 also includes a plurality of second microstructures 23 located within the substrate 21. The second microstructures 23 extend along a first direction X and are periodically arranged along a second direction Y. The orthographic projections of the first microstructure 22 and the second microstructures 23 on the second surface M2 are alternately arranged along the second direction Y. The orthographic projection of the second microstructure 23 on the first cross-section forms a second isosceles triangle, with the base of the second isosceles triangle located on the second surface M2. Adjacent first microstructures 22 and second microstructures 23 form an incident light transmission channel or an outgoing light transmission channel. The light transmittance of the substrate 21 is less than the light transmittance of the second microstructures 23.

[0035] In the embodiments of this application, reference is made to Figure 4 and Figure 5 The optical film 20 provided in this embodiment can also be designed such that a first light-absorbing microstructure 22 is provided on the first surface M1 of the substrate 21, and a second light-absorbing microstructure 23 is provided on the second surface M2, both of which have isosceles triangular cross sections, and both are along... Figure 4 The light rays are arranged in an alternating periodic pattern along the Y-direction. This allows the incident light transmission channel A and the outgoing light transmission channel B to be symmetrical about the first microstructure 22 or about the second microstructure 23. This ensures that at least a portion of the light rays propagating along the incident light transmission channel A are reflected by the second surface M2 and exit the optical film 20 along the outgoing light transmission channel B, while light rays outside the incident light transmission channel A are absorbed by the first microstructure 22 or the second microstructure 23. This effectively selects light rays with specific incident angles for exit. For example, refer to... Figure 5As shown, the first portion of light S1 is incident on the second surface M2 of the substrate 21 through the incident light transmission channel A formed between two adjacent first microstructures 22 and between the first microstructure 22 and the second microstructure 23. After being reflected by the second surface M2, it is emitted from the first surface M1 through the outgoing light transmission channel B formed between the first microstructure 22 and the second microstructure 23 and between two adjacent first microstructures 22. The second portion of light S2 is directly absorbed by the first microstructure 22. At this time, the first portion of light S1 is the image light transmitted to the human eye, and the second portion of light S2 is the ambient light that will not be transmitted to the human eye and needs to be blocked.

[0036] It should be noted that the first part of the light ray S1 and the second part of the light ray S2 in the accompanying drawings of the embodiments of this application are merely illustrative examples, and the actual light ray paths may be the same or similar. The embodiments of this application do not impose specific limitations.

[0037] refer to Figure 4 and Figure 5 When the first microstructure 22 and the second microstructure 23 are simultaneously provided in the optical film 20, there are multiple structural designs for the structural dimensions of the first microstructure 22 and the second microstructure 23.

[0038] One feasible implementation method, see reference Figure 4 and Figure 5 The first isosceles triangle has a dimension of d1 in the second direction Y, a height of h1, and a first incident angle of θ1. The base 21 has a dimension of T in the third direction, and the second isosceles triangle has a height of h2. The dimensional parameters of the first microstructure 22 and the second microstructure 23 satisfy: d1 = 2T × tanθ1, h1 ≤ T, h2 ≤ T. Here, the third direction Z is the thickness direction of the base 21.

[0039] In this embodiment, the dimension d1 of the first microstructure 22 along the Y direction in the figure is related to the thickness T of the optical film 20 and the minimum incident angle (first incident angle θ1) of the first portion of the light S1 that the user needs to reflect. According to the geometric relationship, it can be reasonably adjusted according to θ1 and T, so that only the first portion of the light S1 with a specific incident angle Δ1 is reflected and emitted after passing through the incident light transmission channel A and the outgoing light transmission channel B formed between the first microstructure 22 and the second microstructure 23. At the same time, it can also block and absorb the second portion of the light S2 with an incident angle Δ2, which has the advantage of flexibility and can meet the application of various incident angles.

[0040] One feasible implementation method is to continue referring to... Figure 4 and Figure 5 The period of the first microstructure 22 is P, where the period of the first microstructure 22 refers to the period along the axis of ... Figure 4The distance between the bottom centers of two adjacent first microstructures 22 in the Y direction. The first isosceles triangle has a dimension d1 and a height h1 in the second direction Y. The second isosceles triangle has a dimension d2 and a height h2 in the second direction Y. The second incident angle is θ2. The base 21 has a dimension T in the third direction Z. The dimensional parameters of the first microstructure 22 and the second microstructure 23 satisfy the following relationships: d1 < 2(PT × tanθ2), h2 = P / (2tanθ2), d2 ≤ P. When the above relationships are satisfied, the second microstructure 23 limits the maximum value of the second incident angle θ2. For light rays with an incident angle greater than θ2, they will be blocked and absorbed by the top of the second microstructure 23.

[0041] One feasible implementation method is to continue referring to... Figure 4 and Figure 5 The dimension d1 of the first microstructure 22 along the Y direction in the figure can also be designed as d1=2(PT×tanθ2), h2≤P / (2tanθ2). When the above relationship is satisfied, the first microstructure 22 limits the maximum value of the second incident angle θ2. For light rays with an incident angle greater than θ2, they will be blocked and absorbed by the bottom of the first microstructure 22.

[0042] Based on geometric relationships, the first microstructure 22 can also be defined along the second incident angle θ2, the period P of the first microstructure 22, and the dimension T of the substrate 21 in the Z direction. Figure 4 The dimensions in the Y direction and the heights h2 and d2 of the second microstructure 23 are set and adjusted reasonably according to the above relationship. In this way, it can be realized that only the first part of the light S1 at a specific incident angle △1 is reflected and emitted after passing through the incident light transmission channel A and the outgoing light transmission channel B formed between the first microstructure 22 and the second microstructure 23. At the same time, it can also block and absorb the second part of the light S2 at the incident angle △2. It has the advantage of flexibility and can meet the application of various incident angles.

[0043] One feasible implementation method is to continue referring to... Figure 3 , combined Figure 4 and Figure 5 It is possible to set only the first microstructure 22 without setting the second microstructure. The dimension d1 of the first microstructure 22 along the Y direction in the figure can also be designed as d1=2(PT×tanθ2).

[0044] In summary, in the embodiments of this application, according to geometric relationships, when the parameters d1 and h1 of the first microstructure 22 and the parameters d2 and h2 of the second microstructure 23 satisfy any of the above relationships, it is possible to achieve the reflection of only the first portion of the light ray S1 at the incident angle Δ1, and the blocking and absorption of the second portion of the light ray S2 at the incident angle Δ2. It should be noted that the structural dimensions of the first microstructure 22 and the second microstructure 23 provided in the embodiments of this application, combined with the first incident angle θ1, the second incident angle θ2, the period P of the first microstructure 22, and the thickness T of the optical film 20, allow for various structural designs, offering the advantage of flexibility and adaptability to meet applications with multiple incident angles.

[0045] Based on the above embodiments, continue to refer to Figure 4 and Figure 5 The first microstructure 22 and the second microstructure 23 are made of the same material, for example, both are black materials, such as carbon black or pigment-based materials, and have the same light absorption effect. This design can also reduce the manufacturing cost and difficulty of the optical film 20.

[0046] Based on the above embodiments, refer to Figure 4 The orthographic projection of the first microstructure 22 onto the second surface M2 does not overlap with the orthographic projection of the second microstructure 23 onto the second surface M2. This design requires balancing the reflection of desired light and the absorption of unwanted ambient light by the optical film 20, while also ensuring the transmittance of the optical film 20 in its thickness direction. For example, refer to... Figure 1 The optical film 20 provided in this application embodiment can be attached to the windshield of a car. The windshield needs to meet a certain transmittance. This application sets that the orthographic projection of the first microstructure 22 on the second surface M2 and the orthographic projection of the second microstructure 23 on the second surface M2 do not overlap, so as to avoid the first microstructure 22 and the second microstructure 23 blocking the light in front of the vehicle, ensuring that the driver's forward vision is clear, thereby ensuring safe driving of the car.

[0047] Figure 6 yes Figure 1 A schematic cross-sectional view of another type of optical film along the AA' direction. Figure 7 yes Figure 4 A cross-sectional schematic diagram of another optical film along the BB' direction, based on the above embodiment, with reference to... Figure 6 and Figure 7 The optical film 20 also includes an anti-reflective film 24 disposed on the second surface M2. This arrangement can improve the reflection efficiency of the second surface M2 on the first portion of the light S1, which is beneficial to improving the brightness and clarity of the virtual image of the head-up display (HUD) in HUD applications.

[0048] Based on the above embodiments, refer to Figure 6 and Figure 7 The refractive index of the antireflective coating 24 is less than that of the substrate 21. By utilizing the principle of total internal reflection, at least a portion of the first part of the incident light S1 can enter the low-refractive-index antireflective coating 24 from the high-refractive-index substrate 21 and undergo total internal reflection, thereby increasing the reflection efficiency of the second surface M2.

[0049] Figure 8 This is a top view schematic diagram of another optical film provided in this application. Based on the above embodiments, the extension length of the first microstructure 22 can be designed in various ways, specifically:

[0050] One feasible implementation method, see reference Figure 2 The first microstructure 22 along Figure 2 The first direction X can be continuous. One possible implementation method is described in reference... Figure 8 The first microstructure 22 along Figure 8 The first direction X can be discontinuous. The first microstructure 22 includes at least two first sub-microstructures 22a, each first sub-microstructure 22a along... Figure 8 The first sub-microstructures 22a are arranged in a multi-array configuration, with spacing between them in the X direction and extending along the X direction and arranging them along the Y direction. This application sets a gap between adjacent first sub-microstructures 22a. This arrangement ensures efficient reflection of the first portion of light S1 within the first sub-microstructure 22a interval, while also improving the transmittance of the optical film 20 in its thickness direction (Z direction in the figure) to meet the transmittance requirements of practical applications.

[0051] Figure 9 This is a top view schematic diagram of another optical film provided in this application. Figure 10 This is a top view schematic diagram of another optical film provided in this application. When the optical film 20 is composed of a first microstructure 22 and a second microstructure 23, in order to improve the transmittance of the optical film 20 in its thickness direction (Z direction in the figure), the first microstructure 22 and the second microstructure 23 can be continuous or discontinuous in the extension direction. Specifically:

[0052] One feasible implementation method, see reference Figure 4 The first microstructure 22 and the second microstructure 23 along Figure 2 The X-direction can be continuous.

[0053] One feasible implementation method, see reference Figure 9 The first microstructure 22 and the second microstructure 23 along Figure 8 The X-direction can be discontinuous. The first microstructure 22 includes at least two first sub-microstructures 22a, each first sub-microstructure 22a along... Figure 9The microstructures are spaced apart in the X direction and extend along the X direction, and are arranged along the Y direction; the second microstructure 23 includes at least two second sub-microstructures 23a, each second sub-microstructure 23a along the X direction and extending along the Y direction. Figure 9 The microstructures are spaced apart in the X direction and extend along the X direction, and arranged along the Y direction. The first sub-microstructure 22a and the second sub-microstructure 23a are arranged along the X direction. Figure 9 The microstructures are arranged alternately in the Y direction to form groups. The gaps between two adjacent first sub-microstructures 22a and between two adjacent second sub-microstructures 23a can improve the transmittance of the optical film 20 in its thickness direction (Z direction in the figure).

[0054] One feasible implementation method, see reference Figure 10 The first microstructure 22 along Figure 10 The X-direction is continuous. The second microstructure 23 is along... Figure 10 The X-direction is discontinuous, and the second microstructure 23 includes at least two second sub-microstructures 23a, each second sub-microstructure 23a along the X-direction. Figure 10 The microstructures are spaced apart in the X direction and extend along the X direction, and arranged along the Y direction. The first sub-microstructure 22a and the second sub-microstructure 23a are arranged along the X direction. Figure 9 The groups are formed by alternating arrangements in the Y direction.

[0055] As shown above, by reasonably setting the lengths of the first microstructure 22 and the second microstructure 23 in the extension direction, the transmittance of the optical film 20 in its thickness direction (Z direction in the figure) can be improved, thus meeting the transmittance requirements of practical applications.

[0056] It should be noted that the length arrangement of the first microstructure 22 and the second microstructure 23 in the extension direction is not limited to that shown in the above embodiments. As long as the incident light transmission channel or the outgoing light transmission channel provided in the above embodiments requires light reflection, it can be reasonably set. The embodiments of this application will not show them one by one.

[0057] Figure 11 This is a top view schematic diagram of another optical film provided in this application. Based on the above embodiment, the optical film 20 can also be divided into regions, and different first microstructures 22 and second microstructures 23 can be set for different regions, so that different regions have different reflectivity and transmittance of light.

[0058] For details, please refer to Figure 11 As shown, the optical film 20 includes at least a first region 20a and a second region 20b. The first region 20a includes a plurality of first microstructures 22, and the second region 20b includes a plurality of first microstructures 22 and a plurality of second microstructures 23. That is, within the first region 20a, a plurality of microstructures are disposed only on the first surface M1. Figure 11The first microstructure 22 extends in the X direction and is arranged along the Y direction. Multiple microstructures along the Y direction are formed on the first surface M1 within the second region 20b. Figure 11 The first microstructure 22 extends in the X direction and is arranged along the Y direction, while multiple microstructures are arranged on the second surface M2 along the X direction. Figure 11 The second microstructure 23, which extends in the X direction and is arranged along the Y direction, differentiates the design of the first region 20a and the second region 20b to meet the requirements of different reflected light.

[0059] The extension length and spacing of the first microstructure 22 in the first region 20a and the second region 20b, as well as the first microstructure 22 and the second microstructure 23 in the second region 20b, can be reasonably set according to specific reflectivity and transmittance requirements. This application embodiment does not impose any restrictions.

[0060] Based on the same inventive concept, this application also provides a head-up display device. Figure 12 This is a schematic diagram of another head-up display device provided in this application. Figure 13 This is a schematic diagram of a head-up display device applied in an automobile, as provided in this application. (Continue to refer to...) Figure 1 The head-up display (HUD) includes an image generation unit 10, a projection substrate 30, and an optical film 20 provided in the above embodiment. The optical film 20 is disposed on the side of the projection substrate 30 near the image generation unit 30, and the second surface M2 of the optical film 20 is attached to the projection substrate 30. (Reference) Figure 3 , Figures 5-7 The image light rays (the first portion of light rays S1) first enter the substrate 21 after hitting the first surface M1 of the optical film 20. They then pass through the incident light transmission channel into the substrate 21, are reflected by the second surface M2, and are output to the outside of the optical film 20 through the outgoing light transmission channel, reaching the user's observation range to form a virtual image. The first portion of light rays S1, transmitted at a specific angle, blocks and absorbs at least a portion of the second portion of light rays S2.

[0061] The optical film provided in this application embodiment can be used to reflect image light emitted only from the direction of the image generation unit into the observation range, and to block or absorb light from non-defined area angles, thereby reducing the amount of light from non-defined area angles reflected or scattered by the projection substrate into the eyes of the person in the observation range, thereby improving ambient light contrast and optimizing the visual effect of virtual image imaging.

[0062] refer to Figure 12The head-up display (HUD) also includes at least one reflector 40. The image light (first part light S1) output by the image generation unit 10 is reflected by the reflector 40 and then incident on the projection substrate 30. The projection substrate 30 is the windshield of a vehicle. By reasonably setting the number and position of the reflectors 40, the direction and angle of the image light output by the image generation unit 10 can be adjusted so that the optical film 20 can completely reflect the image light, block the ambient light, and further optimize the virtual image imaging effect.

[0063] It should be noted that the projection substrate 30 can be a separately set substrate or a vehicle windshield. When the optical film 20 is assembled in the vehicle windshield or a separately set substrate, it also has the beneficial effects of the optical film in the above embodiments. The similarities can be understood by referring to the explanation of the optical film above, and will not be repeated below.

[0064] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. An optical film, characterized in that, include: A substrate, the substrate including a first surface and a second surface disposed opposite to each other; Multiple first microstructures are located within the substrate. The first microstructures extend along a first direction and are periodically arranged along a second direction. The orthographic projection of the first microstructure on the first cross section is a first isosceles triangle. The base of the first isosceles triangle is located on the first surface. An incident light transmission channel or an outgoing light transmission channel is formed between two adjacent first microstructures. The first direction intersects the second direction, and the first cross section is perpendicular to the first direction. Wherein, the light transmittance of the substrate is greater than the light transmittance of the first microstructure; The first portion of light incident on the first surface is incident into the substrate through the incident light transmission channel, and is reflected by the second surface and output to the outside of the optical film through the outgoing light transmission channel; the second portion of light incident on the first surface is absorbed by the first microstructure.

2. The optical film according to claim 1, characterized in that, It also includes a plurality of second microstructures located within the substrate, the second microstructures extending along the first direction and periodically arranged along the second direction, the orthographic projections of the first microstructures on the second surface and the orthographic projections of the second microstructures on the second surface being alternately arranged along the second direction; The orthographic projection of the second microstructure onto the first cross section is a second isosceles triangle, the base of which is located on the second surface. Adjacent first and second microstructures form an incident light transmission channel or an outgoing light transmission channel. The light transmittance of the substrate is greater than that of the second microstructure.

3. The optical film according to claim 2, characterized in that, The first microstructure and the second microstructure are made of the same material.

4. The optical film according to claim 2, characterized in that, The orthographic projection of the first microstructure onto the second surface does not overlap with the orthographic projection of the second microstructure onto the second surface.

5. The optical film according to claim 1, characterized in that, It also includes an antireflective film disposed on the second surface.

6. The optical film according to claim 5, characterized in that, The refractive index of the antireflective coating is less than that of the substrate.

7. The optical film according to claim 1, characterized in that, Along the first direction, the first microstructure includes at least two first sub-microstructures.

8. The optical film according to claim 2, characterized in that, Along the first direction, the first microstructure includes at least two first sub-microstructures, and / or the second microstructure includes at least two second sub-microstructures.

9. The optical film according to claim 2, characterized in that, The optical film includes at least a first region and a second region, wherein the first region includes a plurality of the first microstructures and the second region includes a plurality of the first microstructures and a plurality of the second microstructures.

10. The optical film according to claim 1, characterized in that, The angle of incidence of the first portion of the light rays is greater than or equal to the first angle of incidence, and less than or equal to the second angle of incidence; The angle of incidence of the second portion of the light is smaller than the first angle of incidence, or larger than the second angle of incidence; Wherein, the incident angle is the angle between the incident point on the first surface and the normal perpendicular to the first surface.

11. The optical film according to claim 10, characterized in that, The optical film also includes a plurality of second microstructures located within the substrate, wherein the orthographic projection of the second microstructure onto the first cross section is a second isosceles triangle; The first isosceles triangle has a dimension of d1 in the second direction, the height of the first isosceles triangle is h1, the height of the second isosceles triangle is h2, the first incident angle is θ1, and the dimension of the base in the third direction is T, where d1 = 2T × tanθ1, h1 ≤ T, and h2 ≤ T. Wherein, the third direction is the thickness direction of the substrate.

12. The optical film according to claim 10, characterized in that, The optical film also includes a plurality of second microstructures located within the substrate, wherein the orthographic projection of the second microstructure onto the first cross section is a second isosceles triangle; The period of the first microstructure is P, the dimension of the first isosceles triangle in the second direction is d1, the height of the first isosceles triangle is h1, the dimension of the second isosceles triangle in the second direction is d2, the height of the second isosceles triangle is h2, the second incident angle is θ2, the dimension of the base in the third direction is T, d1 < 2(PT × tanθ2), h2 = P / (2tanθ2), d2 ≤ P. Wherein, the third direction is the thickness direction of the substrate.

13. The optical film according to claim 10, characterized in that, The optical film also includes a plurality of second microstructures located within the substrate, wherein the orthographic projection of the second microstructure onto the first cross section is a second isosceles triangle; The period of the first microstructure is P, the dimension of the first isosceles triangle in the second direction is d1, the height of the first isosceles triangle is h1, the dimension of the second isosceles triangle in the second direction is d2, the height of the second isosceles triangle is h2, the second incident angle is θ2, the dimension of the substrate in the third direction is T, d1=2(PT×tanθ2), h2≤P / (2tanθ2), wherein the third direction is the thickness direction of the substrate.

14. The optical film according to claim 10, characterized in that, The period of the first microstructure is P, the dimension of the first isosceles triangle in the second direction is d1, the height of the first isosceles triangle is h1, the second incident angle is θ2, and the dimension of the substrate in the third direction is T, d1=2(PT×tanθ2), wherein the third direction is the thickness direction of the substrate.

15. The optical film according to claim 10, characterized in that, The angle of incidence of the first portion of the light rays is greater than or equal to 10° and less than or equal to 30°; The incident angle of the second part of the light is less than 10° or greater than 30°.

16. A head-up display device, characterized in that, It includes an image generating unit, a projection substrate, and an optical film as described in any one of claims 1 to 15, wherein the optical film is disposed on the side of the projection substrate near the image generating unit.

17. The head-up display device according to claim 16, characterized in that, It also includes at least one reflector, and the image light output by the image generation unit is reflected by the reflector and then incident on the projection substrate.

18. The head-up display device according to claim 16, characterized in that, The projection substrate is a vehicle windshield.

Images