Head-up display system and projection lens thereof

Abstract

The invention relates to the technical field of optical lenses, and provides a head-up display system and a projection lens thereof. The projection lens comprises a first lens group, a second lens group, a third lens group and a fourth lens group which are sequentially arranged along an optical axis from an image side to an object side, the first lens group comprises a first lens with positive focal power; the second lens group comprises a second glued lens with negative focal power; the third lens group comprises a third glued lens with positive focal power; the fourth lens group comprises a sixth lens with positive focal power; the optical surfaces of the first lens, the second glued lens, the third glued lens and the sixth lens are spherical optical surfaces. According to the projection lens, the four lens groups are arranged, and the optical surfaces of the four lens groups are spherical optical surfaces, so that the lens groups of the projection lens are simple in structure and convenient to process and manufacture, the manufacturing cost is low, the tolerance performance is high, and the quality of the projection lens is improved.

Description

Technical Field

[0001] This application relates to the field of optical lens technology, and in particular to a head-up display system and its projection lens. Background Technology

[0002] The projection lens is a key component of a head-up display system, playing a crucial role in the clarity, accuracy, and visual experience of the projected information. However, commercially available projection lenses often have complex structures, which hinders the improvement of projection lens quality. Summary of the Invention

[0003] In view of this, this application aims to provide a projection lens to improve the quality of the projection lens.

[0004] To achieve the above objectives, the technical solution of this application is implemented as follows: A projection lens includes: a first lens group, a second lens group, a third lens group, and a fourth lens group arranged sequentially along the optical axis from the image side to the object side; The first lens group includes a first lens with positive optical power; the second lens group includes a second cemented lens with negative optical power; the third lens group includes a third cemented lens with positive optical power; and the fourth lens group includes a sixth lens with positive optical power. The optical surfaces of the first lens, the second cemented lens, the third cemented lens, and the sixth lens are all spherical optical surfaces.

[0005] Furthermore, the second cemented lens includes a second lens and a third lens arranged sequentially along the optical axis from the image side to the object side; The third cemented lens includes a fourth lens and a fifth lens arranged sequentially along the optical axis from the image side to the object side.

[0006] Furthermore, an aperture stop is provided along the optical axis on the side of the first mirror group opposite to the second mirror group.

[0007] Furthermore, the projection lens has a focal length f=1mm, a relative aperture (D / f)=1 / 1.44, a full field of view 2w=12°, and a back working distance greater than 0.75mm.

[0008] Furthermore, the projection lens employs a refractive optical path.

[0009] Compared with related technologies, this application has the following advantages: (1) The projection lens described in this application has four lens groups and the optical surfaces of the four lens groups are all spherical optical surfaces, which makes the lens group structure of the projection lens simple and easy to process and manufacture. At the same time, the manufacturing cost is low and the tolerance performance is strong, which is conducive to improving the quality of the projection lens.

[0010] (2) Meanwhile, the projection lens of this application has a full field of view of 12 degrees and has high resolution, high contrast and good color difference correction.

[0011] (3) It is highly versatile. By making appropriate adjustments to the air gap of each lens group and the curvature radius of individual lenses, it can be used for digital projectors with different light sources ranging from 0.23 to 0.8 inches based on DLP, LCD or LCOS chip sizes, as well as CCD or CMOS photography and surveillance cameras with chip sizes ranging from 1 / 3 to 4 / 3 inches.

[0012] Another objective of this application is to provide a head-up display system having a projection lens as described above.

[0013] Furthermore, the head-up display system also includes a display medium located along the optical axis on the light-emitting side of the projection lens.

[0014] The head-up display system described in this application, by setting up the projection lens as described above, is conducive to having good image quality and reducing the cost of the head-up display system. Attached Figure Description

[0015] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings: Figure 1 This is a schematic diagram of the projection lens structure described in an embodiment of this application; Figure 2 This is a schematic diagram of ray tracing of the projection lens described in an embodiment of this application; Figure 3 This is a schematic diagram of the head-up display system described in an embodiment of this application.

[0016] Explanation of reference numerals in the attached figures: 1. First lens group; 101. First lens; 2. Second lens group; 201. Second lens; 202. Third lens; 3. Third lens group; 301. Fourth lens; 302. Fifth lens; 4. Fourth lens group; 401. Sixth lens; 5. Aperture; 6. Display medium; A. Optical axis; P1. Image side; P2. Object side. Detailed Implementation

[0017] To make the technical solution and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0018] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0019] Furthermore, it should be noted that in the description of this application, if terms such as "upper," "lower," "inner," or "outer" appear, indicating orientation or positional relationship, these are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this application and simplifying the description, and do not 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 on this application. In addition, if terms such as "first" or "second" appear, they are also used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0020] Furthermore, in the description of this application, unless otherwise expressly defined, the terms "installation," "connection," "joining," and "connector" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; 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; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application in light of the specific circumstances.

[0021] In this application, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0022] The present application will now be described in detail through exemplary embodiments. However, it should be understood that, without further description, elements, structures, and features in one embodiment may be advantageously incorporated into other embodiments.

[0023] An embodiment of the first aspect of this application provides a projection lens that can be applied in a head-up display system to project image light signals onto a designated imaging carrier. Furthermore, the projection lens of this application, through its innovative structural design, makes the projection lens simple in structure, easy to manufacture, and low in cost.

[0024] In related technologies, the projection lenses commonly used on the market usually use aspherical lenses. Since the center of curvature of an aspherical lens is not a fixed point and the surface shape of the lens is not part of a standard sphere, the lens structure is complex, the processing is difficult and the production cost is high, which is not conducive to improving the quality of the projection lens.

[0025] In view of this, in order to overcome the shortcomings of related technologies, the projection lens in this embodiment combines... Figure 1 and Figure 2 As shown, the overall design includes a first lens group 1, a second lens group 2, a third lens group 3, and a fourth lens group 4 arranged sequentially along the optical axis A from the image side P1 to the object side P2; the first lens group 1 includes a first lens 101 with positive optical power; the second lens group 2 includes a second cemented lens with negative optical power; the third lens group 3 includes a third cemented lens with positive optical power; and the fourth lens group 4 includes a sixth lens 401 with positive optical power.

[0026] Among them, the optical surfaces of the first lens 101, the second cemented lens, the third cemented lens and the sixth lens 401 are all spherical optical surfaces.

[0027] Therefore, by setting the first lens group 1, the second lens group 2, the third lens group 3 and the fourth lens group 4, and setting the optical surfaces of the above four lens groups to be spherical optical surfaces, the lens group structure of the projection lens is simple and easy to process and manufacture. At the same time, the manufacturing cost is low and the tolerance performance is strong, which is conducive to improving the quality of the projection lens.

[0028] It is worth noting that, in the embodiments of this application, the object side P2 refers to the side where the carrier that generates the original image signal is located, while the image side P1 refers to the side where the projection lens refracts the light to form the image.

[0029] In some of the exemplary implementations, combined with Figure 1 and Figure 2 As shown, the second cemented lens includes a second lens 201 and a third lens 202 arranged sequentially along the optical axis A from the image side P1 to the object side P2; the third cemented lens includes a fourth lens 301 and a fifth lens 302 arranged sequentially along the optical axis A from the image side P1 to the object side P2.

[0030] It is understandable that the optical surfaces of the first lens 101 and the second lens 201 bonded together have the same radius of curvature. Similarly, the optical surfaces of the fourth lens 301 and the fifth lens 302 bonded together also have the same radius of curvature.

[0031] Based on the above overall introduction, specifically, combined with Figure 1 and Figure 2As shown, the optical surfaces of the first lens 101, the second cemented lens, the third cemented lens, and the sixth lens 401 are all spherical optical surfaces. That is, the optical surfaces on both sides of each of the first lens 101, the second lens 201, the third lens 202, the fourth lens 301, the fifth lens 302, and the sixth lens 401 used to deflect light are all spherical optical surfaces. Taking the first lens 101 as an example, the optical surface that the light touches when it first enters the first lens 101 is a spherical optical surface, and the optical surface that the light passes through when it exits the first lens 101 is also a spherical optical surface.

[0032] In some exemplary embodiments, an aperture stop 5 is provided along the optical axis A on the side of the first mirror group 1 opposite to the second mirror group 2. The projection lens employs a refractive optical path.

[0033] In some of the exemplary embodiments, the projection lens has a focal length f=1mm, a relative aperture (D / f)=1 / 1.44, a full field of view 2w=12°, and a back working distance greater than 0.75mm.

[0034] As described above, the projection lens of this application achieves a full field of view of 12°, and possesses high resolution, high contrast, and good color difference correction. Furthermore, the projection lens of this application exhibits strong versatility. Specifically, by appropriately adjusting the air gap between each lens group and the curvature radius of individual lenses, it can be used with digital projectors based on different light sources with DLP, LCD, or LCOS chip sizes ranging from 0.23 to 0.8 inches, as well as with CCD or CMOS cameras with chip sizes ranging from 1 / 3 to 4 / 3 inches for photography, video recording, and surveillance.

[0035] It is understandable that, in addition to the first lens group 1, the second lens group 2, the third lens group 3, the fourth lens group 4 and the aperture 5 as described above, the projection lens also includes a lens barrel for mounting the above-mentioned multiple lens groups and apertures, as well as other components. The above-mentioned multiple lens groups and apertures are all installed in the lens barrel, and the design style and setting method of the specific lens barrel and other components can refer to the existing design.

[0036] Based on the above description, the structural parameters of this projection lens when the focal length is 1mm are as follows:

[0037] It is worth noting that "Surface" in Chinese means "surface number," referring to the numbering of the optical surfaces of aperture 5, first lens 101, second lens 201, third lens 202, etc. The numbers in the same column correspond to the optical surfaces of aperture 5 and first lens 101 to sixth lens 401, respectively. For example, in the "Surface" column, the number 3 is the number of the optical surface of first lens 101 near aperture 5, while the number 6 in the same column is the number of the optical surface of second lens 201 and third lens 202 that are cemented together. That is, the optical surfaces of cemented lens groups that are cemented together share the same number.

[0038] It is also worth noting that "Type" in Chinese means surface type, and in the same column, "STANDARD" refers to a standard optical surface; "Radius" in Chinese means the radius of curvature of the optical surface; "Thickness" in Chinese means the distance between two adjacent optical surfaces. If two adjacent optical surfaces belong to the same lens, then "Thickness" refers to the thickness of the lens; "Material" in Chinese means the material used in each lens. The two values ​​in this column represent the refractive index and Abbe number of the lens, respectively. The refractive index and Abbe number determine the refractive ability and dispersion control of light. The existing interpretations of the English terms mentioned above are acceptable.

[0039] It is understood that, regarding the projection lens of this embodiment, based on the above exemplary embodiments, in specific implementation, as a preferred embodiment, it is still combined with... Figure 1 and Figure 2 As shown, it may include, for example, a first lens group 1, a second lens group 2, a third lens group 3, and a fourth lens group 4 arranged sequentially along the optical axis A from the image side P1 to the object side P2; the first lens group 1 includes a first lens 101 with positive optical power; the second lens group 2 includes a second cemented lens with negative optical power; the third lens group 3 includes a third cemented lens with positive optical power; the fourth lens group 4 includes a sixth lens 401 with positive optical power; the optical surfaces of the first lens 101, the second cemented lens, the third cemented lens, and the sixth lens 401 are all spherical optical surfaces.

[0040] The second cemented lens includes a second lens 201 and a third lens 202 arranged sequentially along the optical axis A from the image side P1 to the object side P2; the third cemented lens includes a fourth lens 301 and a fifth lens 302 arranged sequentially along the optical axis A from the image side P1 to the object side P2.

[0041] Furthermore, an aperture 5 is provided along the optical axis A on the side of the first lens group 1 away from the second lens group 2. The focal length of the projection lens is f=1mm, the relative aperture (D / f) is 1 / 1.44, the full field of view 2w=12°, and the back working distance is greater than 0.75mm.

[0042] In the preferred embodiment of the projection lens described above, the specific settings and arrangements of the aperture 5, the first lens group 1, the second lens group 2, etc., can still be referred to the descriptions in the above exemplary embodiments. Furthermore, the beneficial effects brought about by the design of this preferred embodiment can also be referred to the descriptions in the above exemplary embodiments.

[0043] As a method for manufacturing the projection lens as described above, the method includes: setting basic optical parameters, including field of view, relative aperture and operating wavelength.

[0044] An equivalent parallel plate is inserted after the fourth mirror group 4 to simulate the internal synthesis prism of the imaging device.

[0045] The system focal length was adjusted to the target value. Based on this, the system was modified and optimized using a design optimization method that combined manual work and design software. During the modification and optimization, the aperture stop 5 was set in front of the first lens group 1.

[0046] By combining precise calculations of aperture and field of view with artificial subdivision, the positions of boundary rays and feature rays are located, the relationships between various aberrations in the lens are found, and aberrations are reasonably matched.

[0047] It is worth noting that in the specific implementation, firstly, the basic optical parameters of the entire system, including the field of view, relative aperture, and working wavelength, are set in the software. Secondly, an equivalent parallel plate of a certain thickness is inserted after the fourth lens group 4 to simulate the internal synthesizing prism of the imaging device, ensuring that the finished lens matches the imaging process. The thickness of the equivalent parallel plate varies depending on the imaging device, and the material of the equivalent parallel plate also varies depending on the imaging device; specific selection criteria and rules for equivalent parallel plates can be referred to. Thirdly, the system focal length is adjusted to the target value. Based on this, a design optimization method combining manual intervention and design software is used to modify and optimize the system. During the modification and optimization, the aperture stop is positioned before the first lens group 1 to facilitate further optimization and correction of aberrations.

[0048] In the later stages of design optimization, precise calculations of aperture and field of view are combined with manual subdivision to accurately locate the positions of boundary and characteristic rays. This allows for effective control of the lens's entrance and exit pupil positions and diameters. Furthermore, the interrelationships of various aberrations within the lens are identified, and aberrations are rationally matched. Through continuous optimization, the lens structure achieves good aberration quality, uniform image plane illumination, and excellent manufacturability. Throughout the optimization process, it is crucial to continuously update and adjust various optimization target values.

[0049] The manufacturing method of the projection lens described above makes the projection lens easy to manufacture and gives it good aberration quality and uniform image plane illumination.

[0050] The projection lens of this embodiment adopts the above design. By setting the first lens group 1, the second lens group 2, the third lens group 3 and the fourth lens group 4, and setting the optical surfaces of the above four lens groups to be spherical optical surfaces, the lens group structure of the projection lens is simple and easy to process and manufacture. At the same time, the manufacturing cost is low and the tolerance performance is strong, which is conducive to improving the quality of the projection lens.

[0051] An embodiment of the second aspect of this application provides a head-up display system, combined with Figure 1 and Figure 3 As shown, the head-up display system is equipped with a projection lens as described in the first aspect. Furthermore, the head-up display system also includes a display medium 6, which is located along the optical axis A on the light-emitting side of the projection lens. It is understood that the display medium 6 is designed to clearly display the pattern formed by the light refracted by the projection lens, and may be, for example, glass, a screen, or a panel.

[0052] The head-up display system described in this application, by setting up the projection lens as described above, is conducive to having good image quality and reducing the cost of the head-up display system.

[0053] The above descriptions are merely some embodiments of this application and are not intended to limit this application. The technical features or structures in the foregoing different embodiments can be arbitrarily combined to form other specific technical solutions as needed. For those skilled in the art, this application can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of the claims of this application.

Claims

1. A projection lens, characterized in that, include: The first mirror group (1), the second mirror group (2), the third mirror group (3) and the fourth mirror group (4) are arranged sequentially along the optical axis (A) from the image side (P1) to the object side (P2); The first lens group (1) includes a first lens (101) with positive optical power; the second lens group (2) includes a second cemented lens with negative optical power; the third lens group (3) includes a third cemented lens with positive optical power; and the fourth lens group (4) includes a sixth lens (401) with positive optical power. The optical surfaces of the first lens (101), the second cemented lens, the third cemented lens, and the sixth lens (401) are all spherical optical surfaces.

2. The projection lens according to claim 1, characterized in that: The second cemented lens includes a second lens (201) and a third lens (202) arranged sequentially along the optical axis (A) from the image side (P1) to the object side (P2); The third cemented lens includes a fourth lens (301) and a fifth lens (302) arranged sequentially along the optical axis (A) from the image side (P1) to the object side (P2).

3. The projection lens according to claim 1, characterized in that: An aperture stop (5) is provided along the optical axis (A) on the side of the first mirror group (1) away from the second mirror group (2).

4. The projection lens according to claim 1, characterized in that: The projection lens has a focal length f=1mm, a relative aperture (D / f)=1 / 1.44, a full field of view 2w=12°, and a back working distance greater than 0.75mm.

5. The projection lens according to claim 1, characterized in that: The projection lens uses a refractive optical path.

6. A head-up display system, characterized in that: The device is equipped with a projection lens as described in any one of claims 1 to 5.

7. The head-up display system according to claim 6, characterized in that, Also includes: The display medium (6) is located on the light-emitting side of the projection lens along the optical axis (A).

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