Optical module and far-image head-up display device
By optimizing the lens assembly and beam splitter design, the head-up display device solves the problems of large device size and high cost, achieves miniaturization and low cost of optical modules, and improves imaging quality and ease of use.
Patent Information
- Application Number
- CN202520048108.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-09
- Publication Date
- 2026-01-13
- Estimated Expiration
- 2035-01-09
AI Technical Summary
Existing head-up display devices suffer from large size and high cost, making it difficult to reduce size and production costs while maintaining image quality.
By employing a combination of mirror bodies and beam-splitting elements with specific angles and proportions, the image light is ensured to undergo three total internal reflections in the optical module. Combined with polarizing beam-splitting films and quarter-wave plates, the optical path folding and light energy utilization are optimized. Spherical or aspherical mirror bodies are used to reduce processing difficulty and cost.
It achieves a reduction in the size of the optical module, especially in the thickness along the direction of human vision, which reduces production costs while improving imaging brightness and visual immersion. It has a wide range of applications and improves ease of use and comfort.
Smart Images
Figure CN223796761U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of head-up display technology and myopia prevention and control, and in particular to an optical module and a head-up display device. Background Technology
[0002] Head-up display devices, such as far-image light screens, can reduce eye strain and fatigue from visual displays, prevent the occurrence and development of myopia, and enhance the immersive experience of the display by pushing the image of the screen further away and magnifying it by a certain factor.
[0003] Conventional head-up display devices, such as head-up screens, use two structural schemes to project the image emitted by the optical engine to the human eye: The first scheme is an optical module composed of a concave mirror and a beam-splitting reflection structure, similar to the Bird Bath optical scheme. The overall device structure is usually large, taking up desktop space. The second scheme is an off-axis dual-mirror scheme, which reflects the image projected by the optical engine to the human eye through two aspherical concave mirrors. Because the surface shape and mirror parameters of the concave mirrors need to be customized, the installation and adjustment are more difficult and the cost is usually higher. Utility Model Content
[0004] Given the shortcomings of existing head-up display devices, such as large size and high cost, it is necessary to provide an optical module and a head-up display device.
[0005] An optical module, comprising:
[0006] The first mirror body has a first surface and a second surface arranged opposite to each other and spaced apart, a third surface and a fourth surface extending gradually from opposite sides of the first surface to the second surface, and the projections of the third surface and the fourth surface onto the second surface are both located within the second surface.
[0007] The second mirror body has a fifth surface glued to the fourth surface and a sixth surface inclined to the fifth surface and arranged relative to the second surface;
[0008] A third mirror body is spaced apart from the first mirror body on the side near the second surface and corresponding to the fourth surface; the third mirror body has a seventh surface; and
[0009] A beam-splitting element is disposed between the fourth surface and the fifth surface;
[0010] The angle α between the fourth surface and the second surface satisfies: 25°≤α≤35°;
[0011] The angle β between the third surface and the second surface satisfies: 50°≤β≤70°;
[0012] The length L1 of the second surface and the projection length L2 of the fourth surface onto the second surface satisfy the condition: L1 / L2≥3.5.
[0013] By setting it up in this way and using the above-mentioned conditional formula to limit the shape of the first mirror body, it is ensured that the image light emitted by the image display unit undergoes total internal reflection during its propagation to the beam splitter element, and the number of total internal reflections is at least three. This improves the light energy utilization rate and helps to enhance the imaging brightness of the eye. It also realizes the folding of the light path, reduces the size of the optical module, and in particular reduces the thickness of the optical module in the direction of human eye vision.
[0014] In one embodiment, the aperture of the third mirror is larger than the aperture of the fourth surface.
[0015] This setup ensures that light from the entire screen can pass smoothly through the optical system and enter the human eye, in other words, it ensures the integrity of the image formed by the optical modules.
[0016] In one embodiment, the first surface, the second surface, and the sixth surface extend vertically.
[0017] This setup facilitates the design of the optical path in the optical module, and the height of the light reflected from the third mirror is consistent with the height of the light emitted from the sixth surface, ensuring that the viewing direction is horizontal.
[0018] In one embodiment, the seventh surface has optical power, and the seventh surface gradually moves away from the second surface from the edge toward the center.
[0019] This setting increases the virtual image distance and magnifies the image displayed in the image unit, which helps reduce eye strain and fatigue, prevent the occurrence and development of myopia, and enhance the visual immersion of the screen.
[0020] In one embodiment, the seventh surface is located on the side of the third mirror body facing the second surface, and the seventh surface has a spherical shape.
[0021] This design enables the reflection of light, and the spherical shape of the seventh surface helps reduce structural complexity and production costs.
[0022] In one embodiment, the third mirror body includes a lens and a reflective film located on the side of the lens opposite to the second surface.
[0023] With this configuration, the structure of the third mirror body causes light to refract when it enters the lens, thereby reducing the optical power requirement of the seventh surface, which in turn reduces the curvature of the seventh surface. This helps to reduce the processing difficulty of the seventh surface and the thickness of the third mirror body, further reducing the size of the optical module.
[0024] In one embodiment, the air gap between the lens and the second surface is greater than or equal to 0.5 mm and less than or equal to 3 mm.
[0025] This design provides ample assembly space for the optical engine support structure and also controls the thickness of the entire optical module in the direction of human vision.
[0026] In one embodiment, the seventh surface is aspherical.
[0027] This setting can correct distortion at the edges of the image, improve image quality, increase the size of the eye box, and enhance visual immersion.
[0028] In one embodiment, the beam splitter includes a polarizing beam splitter film located between the fourth surface and the fifth surface, a first polarizing film attached to the side of the polarizing beam splitter film closer to the fifth surface, and the optical module further includes a quarter-wave plate located between the second surface and the third mirror body;
[0029] The polarizing beam splitter is used to reflect the first linearly polarized light and transmit the second linearly polarized light perpendicular to the polarization direction of the first linearly polarized light. The first polarizing film is used to transmit the second linearly polarized light and absorb the first linearly polarized light. The angle between the fast axis of the quarter-wave plate and the transmission axis of the first polarizing film is 45° or 135°.
[0030] This setup reduces the impact of stray light on imaging, enhances immersion, reduces dizziness, and helps increase the overall light energy utilization of the optical path, thereby increasing the brightness of the image and improving image quality.
[0031] This application also provides a remote head-up display device, including:
[0032] Image display unit; and
[0033] As described above, in the optical module, the image display unit is placed on the third surface of the optical module.
[0034] With this configuration, the image display unit, together with the optical module provided in this application, forms a remote head-up display device with a small front-to-back (viewing direction) size and low production cost. The viewing distance of this remote head-up display device provided in this application is 50mm to 330mm, which has a wide range of applications, allowing the head to be clearly imaged at various distances from the device, thus improving ease of use and comfort.
[0035] In one embodiment, the air gap between the image display unit and the third surface is greater than or equal to 0.5 mm.
[0036] This design allows for ample assembly space for the optical engine support structure and also controls the thickness of the entire head-up display device in the front and back (viewing direction). Attached Figure Description
[0037] Figure 1 This is a schematic diagram of the structure of a head-up display device for distant images according to one embodiment of the present invention;
[0038] Figure 2 for Figure 1 The diagram shows the dimensions of the head-up display device.
[0039] Figure 3 for Figure 1 The diagram shows the optical path of the head-up display device for a distance of 50mm from the eye.
[0040] Figure 4 for Figure 1 The diagram shows the optical path of the head-up display device at an eye distance of 330mm.
[0041] Figure label:
[0042] 10. First mirror body; 101. First surface; 102. Second surface; 103. Third surface; 104. Fourth surface; 20. Second mirror body; 201. Fifth surface; 202. Sixth surface; 30. Third mirror body; 301. Seventh surface; 31. Lens; 32. Reflective film; 33. Quarter-wave plate; 40. Beam splitter; 41. Polarizing beam splitter film; 42. First polarizing film; 50. Image display unit; 62. Third polarizing film. Detailed Implementation
[0043] To make the above-mentioned objects, features, and advantages of this utility model more apparent and understandable, the specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a full understanding of this utility model. However, this utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this utility model. Therefore, this utility model is not limited to the specific embodiments disclosed below.
[0044] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.
[0045] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this utility model, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.
[0046] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.
[0047] In this utility model, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.
[0048] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.
[0049] Head-up display devices, such as far-image light screens, can reduce eye strain and fatigue from visual displays, prevent the occurrence and development of myopia, and enhance the immersive experience of the display by pushing the image of the screen further away and magnifying it by a certain factor.
[0050] Conventional head-up display devices, such as head-up screens, use two structural schemes to project the image emitted by the optical engine to the human eye: The first scheme is an optical module composed of a concave mirror and a beam-splitting reflection structure, similar to the Bird Bath optical scheme. The overall device structure is usually large, taking up desktop space. The second scheme is an off-axis dual-mirror scheme, which reflects the image projected by the optical engine to the human eye through two aspherical concave mirrors. Because the surface shape and mirror parameters of the concave mirrors need to be customized, the installation and adjustment are more difficult and the cost is usually higher.
[0051] Therefore, it is necessary to provide an optical module and a head-up display device that is smaller in size, lower in cost, and still able to guarantee image quality.
[0052] Please see Figures 1 to 4 , Figure 1 This is a schematic diagram of the structure of a head-up display device for distant images according to one embodiment of the present invention. Figure 2 for Figure 1 The diagram shows the dimensions of the head-up display device. Figure 3 for Figure 1 The diagram shows the optical path of the head-up display device at an eye-adaptive distance of 50mm. Figure 4 for Figure 1The diagram shows the optical path of the head-up display device at an eye-adaptive distance of 330mm. The head-up display device includes an optical module with a third surface 103 and a sixth surface 202, and an image display unit 50 disposed on the third surface 103. Specifically, the optical module includes a first mirror body 10, a second mirror body 20, a third mirror body 30, and a beam splitter 40. The first mirror body 10 has a first surface 101, a second surface 102, a third surface 103, and a fourth surface 104. The first surface 101 and the second surface 102 are arranged horizontally opposite each other and spaced apart. The third surface 103 and the fourth surface 104 are arranged vertically opposite each other and spaced apart, extending gradually from opposite sides of the reflecting surface to the second surface 102. That is, the third surface 103 gradually tilts downwards from left to right, and the first tilted surface gradually tilts upwards from left to right. In other words, the projections of the third surface 103 and the fourth surface 104 onto the second surface 102 are both located within the second surface 102. The second mirror body 20 has a fifth surface 201 and a sixth surface 202. The fifth surface 201 is bonded to the fourth surface 104, and the sixth surface 202 is arranged obliquely to the fifth surface 201 and opposite to the second surface 102. The third mirror body 30 is spaced apart from the first mirror body 10 on the side near the second surface 102. The third mirror body 30 corresponds to the fourth surface 104 and has a seventh surface 301. The beam splitter 40 is disposed between the fourth surface 104 and the fifth surface 201. Specifically, the image light emitted by the image display unit 50 enters the first mirror body 10 from the third surface 103, and is reflected sequentially by the second surface 102, the first surface 101, the second surface 102, and the beam splitter 40. It then exits from the second surface 102, is reflected again by the third mirror body 30, and passes sequentially through the first mirror body 10, the beam splitter 40, and the second mirror body 20 before reaching the human eye. In this way, the light path is folded three times by total internal reflection within the first mirror body 10, reducing the size of the optical module, especially its thickness in the direction of human eye vision. In the aforementioned optical module, the angle α between the fourth surface 104 and the second surface 102 satisfies: 25°≤α≤35°, and the angle β between the third surface 103 and the second surface 102 satisfies: 50°≤β≤70°. The length L1 of the second surface 102 and the projection length L2 of the fourth surface 104 on the second surface 102 satisfy: L1 / L2≥3.5. Thus, by using the above-mentioned conditional expressions to define the shape of the first mirror body 10, it is ensured that the image light emitted by the image display unit 50 undergoes total internal reflection during its propagation to the beam splitter, with at least three total internal reflections. This improves light energy utilization and helps enhance the brightness of the visual image, achieving optical path folding and reducing the size of the optical module, particularly its thickness in the human eye's viewing direction. The head-up display device constructed by the image display unit 50 and the optical module provided in this application thus also has a smaller size, particularly in terms of thickness in the human eye's viewing direction, and lower production costs.The viewing distance of the head-up display device provided in this application is 50mm to 330mm, which has a wide range of applications and enables clear imaging of the head at various distances from the device, thereby improving ease of use and comfort.
[0053] Optionally, in one embodiment provided in this application, the light-transmitting aperture of the third mirror 30 is larger than that of the fourth surface 104. In this way, it is ensured that the light of the entire screen frame can pass smoothly through the entire optical system and enter the human eye. In other words, the integrity of the image formed by the optical module is ensured.
[0054] Optionally, in one embodiment provided in this application, the first surface 101, the second surface 102 and the sixth surface 202 extend vertically, which facilitates the design of the optical path in the optical module. Moreover, the height of the light reflected from the seventh surface 301 is consistent with the height of the light emitted from the sixth surface, ensuring that the viewing direction is horizontal, which meets the level viewing direction required for standard eye use.
[0055] Optionally, in one embodiment provided in this application, the seventh surface 301 has optical power, and the seventh surface 301 gradually moves away from the second surface 102 from the edge towards the center. This increases the virtual image distance (actually 3.5m, which is in line with the screen distance for myopia prevention) and magnifies the image of the image display unit 50, which is beneficial to reduce eye strain, prevent the occurrence and development of myopia, and enhance the visual immersion of the screen.
[0056] Optionally, in one embodiment provided in this application, the seventh surface 301 is located on the side of the third mirror 30 facing the second surface 102, and the surface of the seventh surface 301 is spherical. In this way, light reflection is achieved, which helps to reduce structural complexity and production costs. The spherical design of the seventh surface 301 also further reduces production costs.
[0057] Optionally, in another embodiment provided in this application, the third mirror body 30 includes a lens 31 and a reflective film 32 located on the side of the lens 31 facing away from the second surface 102. Optionally, the reflective film 32 is made of a non-transparent material. In this way, when the refractive power of the third mirror body 30 is constant, the structure of the third mirror body 30 reduces the optical power requirement of the seventh surface 301 by causing refraction when light enters the lens 31, thereby reducing the curvature of the seventh surface 301. This helps to reduce the manufacturing cost of the seventh surface 301 and the thickness of the third mirror body 30, further reducing the size of the optical module. Optionally, the air gap between the lens 31 and the second surface 102 is greater than or equal to 0.5 mm and less than or equal to 3 mm, which provides assembly allowance for the optomechanical support structure and controls the thickness of the entire optical module in the human eye's viewing direction.
[0058] Optionally, in one embodiment provided in this application, the seventh surface 301 is aspherical, which can correct distortion at the edges of the image, improve image quality, increase the eye size, and enhance visual immersion. It is understood that in other scenarios, such as when used for artistic presentations like creative images or videos, the seventh surface 301 can also be spherical for ease of processing.
[0059] Optionally, in order to further eliminate the influence of stray light in the lens on imaging, thereby enhancing immersion and reducing dizziness, in one embodiment provided in this application, the beam splitter 40 includes a polarizing beam splitter 41 located between the fourth surface 104 and the fifth surface 201, and a first polarizing film 42 attached to the side of the polarizing beam splitter 41 near the fifth surface 201. The polarizing beam splitter 41 is used to reflect the first linearly polarized light and transmit the second linearly polarized light perpendicular to the polarization direction of the first linearly polarized light. The first polarizing film 42 is used to transmit the second linearly polarized light and absorb the first linearly polarized light. The optical module also includes a quarter-wave plate 33 located between the second surface 102 and the third lens 30. The angle between the fast axis of the quarter-wave plate 33 and the transmission axis of the first polarizing film 42 is 45° or 135°. This also helps to increase the light energy utilization rate of the overall optical path, thereby increasing the brightness of the image entering the eye and improving the image quality. It is understandable that when the light emitted by the image display unit 50 is linearly polarized, the image display unit 50 can be directly placed on the third surface 103. When the light emitted by the image display unit 50 is non-linearly polarized, the optical module also includes a second polarizing film placed on the third surface 103. This second polarizing film is used to transmit the first linearly polarized light and absorb the second linearly polarized light. This avoids the stray light generated after the image light reflected from the first mirror 10 directly passes through the beam splitter 40 and is reflected multiple times in the second mirror 20, thereby improving the reflection / transmission efficiency of polarized light within the entire optical module and increasing the light energy utilization rate. Specifically, the polarizing beam splitter 41 uses a PBS (Polarizing Beam Splitter) film to achieve the beam splitting effect.
[0060] Optionally, to facilitate processing and increase the structural stability of the optical module, in one embodiment provided in this application, the polarizing beam splitter 41 is attached to the fourth surface 104, and the first polarizing film 42 is attached to the fifth surface 201. It is understood that in other embodiments, other types of films, such as AR anti-reflection films, may be disposed between the polarizing beam splitter 41 and the fourth surface 104, and between the first polarizing film 42 and the fifth surface 201.
[0061] Optionally, in one embodiment provided in this application, the sixth surface 202 is also provided with a third polarizing film 62. The third polarizing film 62 is used to transmit the second linearly polarized light and absorb the first linearly polarized light, thereby further reducing the risk of stray light caused by the transmission of the first linearly polarized light and improving the polarization degree of the effective light.
[0062] Optionally, in one embodiment provided in this application, the air gap between the image display unit 50 and the third surface 103 is greater than or equal to 0.5 mm. This reserved air gap provides an assembly allowance for the optomechanical bearing structure of the image display unit 50 and the third surface 103, avoiding scratches between the image display unit 50 and the third surface 103 during assembly, which is beneficial to protecting the first mirror body 10 and the image display unit 50.
[0063] For example, such as Figure 1 As shown, in one embodiment provided in this application, L1 = 346 mm, α = 35°, β = 70°, L1 / L2 = 4, that is, L2 = 86.5 mm. Thus, after light is emitted from the image display unit, it undergoes two reflections on the second surface 102 and one reflection on the first surface 101 before reaching the beam splitter 40 located on the fourth surface 104. The light reflected by the beam splitter 40 is horizontal and exits from the second surface. After reflection by the third mirror 30, it continues horizontally, passing sequentially through the second surface 102, the fourth surface 104, the beam splitter 40, and the fifth surface 201, and exits horizontally from the sixth surface 202. In this embodiment, the thickness of the optical module in the front-to-back direction (horizontal viewing direction) is 60.57 mm, that is, the maximum thickness is 60.57 mm. It can be understood that when α = 25° and β = 50°, the minimum module thickness to achieve three total internal reflections within the optical module is 40.34 mm. The thickness of the entire optical engine module is no more than the width of a palm, which reduces the width of the head-up display device and saves desktop space.
[0064] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0065] The embodiments described above are merely illustrative of several implementations of this utility model, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.
Claims
1. An optical module characterized by comprising: The optical module comprises: a first mirror body having a first surface and a second surface arranged oppositely and spaced apart, a third surface and a fourth surface extending away from opposite sides of the first surface to the second surface respectively, the third surface and the fourth surface being projected on the second surface; a second mirror body having a fifth surface glued to the fourth surface and a sixth surface inclined to the fifth surface and arranged oppositely to the second surface; a third mirror body arranged spaced apart on a side of the first mirror body close to the second surface and corresponding to the fourth surface, the third mirror body having a seventh surface; a light splitting element arranged between the fourth surface and the fifth surface; an angle α between the fourth surface and the second surface satisfies 25°≤α≤35°; an angle β between the third surface and the second surface satisfies 50°≤β≤70°; a length L1 of the second surface and a length L2 of the fourth surface projected on the second surface satisfy L1 / L2≥3.
5. An aperture of the third mirror body is larger than an aperture of the fourth surface.
2. The optical module according to claim 1, wherein The first surface, the second surface and the sixth surface extend along a vertical direction respectively.
3. The optical module according to claim 1, wherein The seventh surface has a focal power, and the seventh surface is gradually away from the second surface from an edge to a center.
4. The optical module according to claim 1, wherein The third mirror body comprises a lens and a reflective film arranged on a side of the lens away from the second surface.
5. The optical module according to claim 4, wherein An air gap between the lens and the second surface ranges from greater than or equal to 0.5 mm to less than or equal to 3 mm.
6. The optical module according to claim 5, wherein The seventh surface is arranged on a side of the third mirror body facing the second surface.
7. The optical module of claim 4, wherein The seventh surface has a spherical or aspherical surface shape.
8. The optical module according to any one of claims 4 to 7, wherein The light splitting element comprises a polarization splitting film arranged between the fourth surface and the fifth surface, and a first polarization film arranged on a side of the polarization splitting film close to the fifth surface, and the optical module further comprises a quarter wave plate arranged between the second surface and the third mirror body.
9. The optical module of claim 1, wherein The optical module comprises:
10. A far vision head-up display device, characterized by an image display unit; and The optical module according to any one of claims 1-9, the image display unit is arranged on a third surface of the optical module, and an air gap between the image display unit and the third surface ranges from greater than or equal to 0.5 mm.