Optical imaging lens group, scanning display device and application

Abstract

The invention discloses an optical imaging lens group, a scanning display device and application, and relates to the technical field of scanning display. The focal length of the first lens of the optical imaging lens group is positive or negative, and the focal lengths corresponding to the second lens to the sixth lens are positive, negative, positive, negative and positive respectively. The focal lengths of the six lenses with the same optical axis of the optical imaging lens group are reasonably optimized and set, so that the focal power of the system can be reasonably dispersed, the aberration generated by the lenses can be reduced, the aim of correcting various aberrations can be fulfilled, and the clear imaging of an image space curved surface can be realized. By configuring the optical imaging lens group in an optical fiber scanner, a miniaturized and lightweight scanning display device can be formed, and the scanning display device is configured and applied to the field of vehicle-mounted projection, so that the requirements of large visual angle, high resolution and low distortion of vehicle-mounted projection can be met.

Description

Technical Field

[0001] This application relates to the technical field of scanning display, and particularly relates to an optical imaging lens group, a scanning display device and an application thereof. Background Art

[0002] As a new display technology, scanning display imaging can be used in various application scenarios such as projection display and near-eye display.

[0003] However, in the existing scanning display imaging systems, there are disadvantages such as poor imaging quality, small field of view angle, and inability to combine miniaturization and lightweight, resulting in certain limitations in the market promotion and application of scanning display imaging technology. Especially when applying scanning display imaging to the scenario of in-vehicle projection, limited by the fact that the product cannot well match the scanning light source of the laser fiber, it is very easy to have problems such as low resolution and large distortion, and it is also very difficult to meet the performance requirements of miniaturization and lightweight. Summary of the Invention

[0004] The purpose of this application is to provide an optical imaging lens group and a scanning display device to meet the requirements of diversified product form, miniaturization and lightweight in the in-vehicle projection scenario.

[0005] Another purpose of this application is to provide an application of a scanning display device, which is configured to be applied in the field of in-vehicle projection and has the characteristics of high imaging quality, miniaturization and lightweight.

[0006] This application provides an optical imaging lens group, which includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens arranged coaxially in sequence from the second side to the first side. The focal length of the first lens is positive or negative, and the focal lengths corresponding to the second lens to the sixth lens are positive, negative, positive, negative, and positive respectively.

[0007] Further, in a preferred embodiment of this application, the following ratio relationship exists between the minimum negative lens in the optical imaging lens group and the total focal length of the optical imaging lens group: 0.4 ≤ |f 最小负 / f 总 | ≤ 0.55, where f 最小负 is the focal length of the minimum negative lens, and f 总 is the total focal length of the optical imaging lens group.

[0008] Further, in a preferred embodiment of this application, the third lens, the fifth lens, and the sixth lens are all cemented lenses combined by a positive lens and a negative lens. The refractive index of the positive lens in the third lens and the fifth lens is less than that of the negative lens, and the refractive index of the positive lens in the sixth lens is greater than that of the negative lens.

[0009] Further, in a preferred embodiment of the present application, at least any one of the following conditions is satisfied by the third lens, the fifth lens, and the sixth lens: the refractive index difference between the negative lens and the positive lens in the third lens is 0.14 to 0.45; the refractive index difference between the negative lens and the positive lens in the fifth lens is 0.05 to 0.18; the refractive index difference between the positive lens and the negative lens in the sixth lens is 0.18 to 0.5.

[0010] Further, in a preferred embodiment of the present application, the positive lens in the sixth lens is closer to the first side relative to the negative lens.

[0011] Further, in a preferred embodiment of the present application, the average refractive index of the negative lenses in the optical imaging lens group is 1.693 to 1.85.

[0012] Further, in a preferred embodiment of the present application, the second side corresponds to the curved surface image of the light source end, the curved surface image is formed by the configuration of the fiber optic scanner, and the surface on the second side of the optical imaging lens group is a concave surface.

[0013] Further, in a preferred embodiment of the present application, the achromatic aberration ability Z of the cemented lens n is represented by the following formula:

[0014] where n is 3, 5, 6, and Z n represents the achromatic aberration ability of the nth lens, f n_1 and f n_2 represent the focal lengths of the positive lens and the negative lens corresponding to the cemented lens; Ab n_1 and Ab n_2 represent the Abbe numbers of the positive lens and the negative lens corresponding to the cemented lens; the achromatic aberration ability Z3 of the third lens is -0.167 to -0.07, the achromatic aberration ability Z5 of the fifth lens is -0.856 to -0.457, and the achromatic aberration ability Z6 of the sixth lens is -0.606 to -0.227.

[0015] The present application further provides a scanning display device, which includes a fiber optic scanner and the aforementioned optical imaging lens group. The fiber optic scanner is used to scan and emit light of an image to be displayed, and the optical imaging lens group is used to magnify and image the scanning surface corresponding to the light emitted by the fiber optic scanner and project it; wherein, the fiber optic scanner includes an actuator and an optical fiber fixed on the actuator, and the part of the optical fiber exceeding the actuator forms an optical fiber cantilever, and the optical fiber cantilever performs two-dimensional scanning under the drive of the actuator.

[0016] The present application further provides an application of the scanning display device as described above, which includes: configuring the scanning display device in the field of vehicle-mounted displays.

[0017] The technical solutions in the embodiments of the present application can achieve the following technical effects:

[0018] In the embodiments of the present application, by reasonably optimizing the focal lengths of six coaxial lenses of the optical imaging lens group, the optical power of the system can be reasonably dispersed, the aberration generated by the lenses can be mitigated, the purpose of correcting various aberrations can be achieved, and clear imaging of the image-side curved surface can be realized; by defining the ratio relationship between the minimum negative lens focal length of multiple said lenses and the total focal length of the optical imaging lens group, the imaging quality of the optical imaging lens group is further ensured; in addition, by providing multiple cemented lenses and reasonably setting their distribution positions, spherical aberration and chromatic aberration in the imaging composition are further eliminated, and the field curvature of the optical imaging lens group is balanced, thereby ensuring the imaging quality of the optical imaging lens group.

[0019] By configuring the above optical imaging lens group in a fiber scanner, a miniaturized and lightweight scanning display device is formed, and by configuring and applying this scanning display device in the field of vehicle-mounted projection, the requirements of large viewing angle, high resolution, and low distortion for vehicle-mounted projection can be achieved.

[0020] Other features and advantages of the present application will be described in the subsequent specification, and, in part, will be obvious from the specification, or will be understood by implementing the technical solutions of the present application. The objectives and other advantages of the present application can be realized and obtained through the structures and / or processes specifically pointed out in the specification, claims, and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] By reading the detailed description of the non-limiting embodiments with reference to the following drawings, other features, objectives, and advantages of the present application will become more obvious:

[0022] Figure 1a , 1b is a schematic structural diagram of an illustrative scanning display system;

[0023] Figure 2a is a schematic diagram of the scanning output of the fiber scanner provided by the embodiment of the present application;

[0024] Figure 2b is a schematic structural diagram of the optical imaging lens group provided by the embodiment of the present application;

[0025] Figure 2c is a schematic diagram of the working distance of the optical imaging lens group provided by the embodiment of the present application;

[0026] Figure 3 is a schematic structural diagram of an optical imaging lens group provided by Embodiment 1 of the present application;

[0027] Figure 4It is the MTF curve graph of the optical imaging lens group in the first embodiment of this application;

[0028] Figure 5 It is the field curvature and distortion curve graph of the optical imaging lens group in the first embodiment of this application;

[0029] Figure 6 It is the lateral chromatic aberration graph of the optical imaging lens group in the first embodiment of this application;

[0030] Figure 7 It is the structural schematic diagram of an optical imaging lens group provided in the second embodiment of this application;

[0031] Figure 8 It is the MTF curve graph of the optical imaging lens group in the second embodiment of this application;

[0032] Figure 9 It is the field curvature and distortion curve graph of the optical imaging lens group in the second embodiment of this application;

[0033] Figure 10 It is the lateral chromatic aberration graph of the optical imaging lens group in the second embodiment of this application;

[0034] Figure 11 It is the structural schematic diagram of an optical imaging lens group provided in the third embodiment of this application;

[0035] Figure 12 It is the MTF curve graph of the optical imaging lens group in the third embodiment of this application;

[0036] Figure 13 It is the field curvature and distortion curve graph of the optical imaging lens group in the third embodiment of this application;

[0037] Figure 14 It is the lateral chromatic aberration graph of the optical imaging lens group in the third embodiment of this application.

[0038] Icons: 100 - Processor; 110 - Laser group; 120 - Fiber optic scanning module; 130 - Transmission fiber; 140 - Light source modulation circuit; 150 - Scanning drive circuit; 160 - Beam combining unit; 121 - Scanning actuator; 121a - Slow axis; 121b - Fast axis; 122 - Fiber optic cantilever; 123 - Lens group; 124 - Scanner package housing; 125 - Fixing part; 230 - Scanning surface; 240 - Imaging plane; 01 - Curved surface image. Detailed implementation manners

[0039] The following further elaborates on this application with reference to the accompanying drawings and embodiments. It can be understood that the specific embodiments described herein are merely used to explain the relevant invention and do not limit the invention. Additionally, it should be noted that for the sake of convenience of description, only the parts related to the relevant invention are shown in the drawings.

[0040] Explanatory Scanning Display System

[0041] For current scanning display imaging, it can be implemented by a Digital Micromirror Device (DMD) or a Fiber Scanning Display (FSD) device. As a new type of scanning display imaging method, the FSD solution realizes the scanning output of an image through a fiber scanner. To enable those skilled in the art to clearly understand the solution of this application, the following briefly describes the principle and corresponding system of fiber scanning imaging.

[0042] As Figure 1a shown, an illustrative scanning display system in this application mainly includes:

[0043] a processor 100, a laser group 110, a fiber scanning module 120, a transmission fiber 130, a light source modulation circuit 140, a scanning drive circuit 150, and a beam combining unit 160.

[0044] Among them, the processor 100 can be a Graphics Processing Unit (GPU), a Central Processing Unit (CPU), or other chips or circuits with control functions and image processing functions, and specific limitations are not made here.

[0045] When the system works, the processor 100 can control the light source modulation circuit 140 to modulate the laser group 110 according to the image data to be displayed. The laser group 110 includes multiple monochromatic lasers that emit light beams of different colors. As can be seen from FIG. 1, red (R), green (G), and blue (B) lasers can be specifically adopted in the laser group. The light beams emitted by the lasers in the laser group 110 are combined into a single laser beam by the beam combining unit 160 and coupled into the transmission fiber 130.

[0046] The processor 100 can also control the scanning drive circuit 150 to drive the fiber scanner in the fiber scanning module 120 to scan, so as to scan and output the light beam transmitted in the transmission fiber 130.

[0047] The light beam scanned and output by the fiber optic scanner acts on a pixel position on the surface of the medium, and a light spot is formed at this pixel position, thus realizing the scanning of this pixel position. Driven by the fiber optic scanner, the output end of the transmission fiber 130 sweeps along a certain scanning trajectory, so that the light beam moves to the corresponding pixel position. During the actual scanning process, the light beam output by the transmission fiber 130 will form a light spot with corresponding image information (such as color, grayscale or brightness) at each pixel position. In the time of one frame, the light beam traverses each pixel position at a high enough speed to complete the scanning of one frame of image. Due to the characteristic of "visual persistence" when the human eye observes things, the human eye cannot perceive the movement of the light beam at each pixel position, but sees a complete frame of image.

[0048] Continue to refer to Figure 1b , which is the specific structure of the fiber optic scanning module 120, including: a scanning actuator 121, a fiber optic cantilever 122, a lens group 123, a scanner encapsulation case 124 and a fixing member 125. The scanning actuator 121 is fixed in the scanner encapsulation case 124 through the fixing member 125. The transmission fiber 130 extends at the front end of the scanning actuator 121 to form a fiber optic cantilever 122 (also called a scanning fiber). During operation, the scanning actuator 121 is driven by a scanning drive signal, and its slow axis 121a (also called the first actuating part) vibrates in the vertical direction (this vertical direction is parallel to Figure 1a , 1b the Y-axis in the reference coordinate system in Figure 1a , 1b and in this application, this vertical direction can also be called the first direction), and its fast axis 121b (also called the second actuating part) vibrates in the horizontal direction (this horizontal direction is parallel to Figure 1a , 1b the X-axis in the reference coordinate system in

[0049] and in this application, this horizontal direction can also be called the second direction). Driven by the scanning actuator 121, the front end of the fiber optic cantilever 122 performs two-dimensional scanning according to a preset trajectory and emits a light beam, and the emitted light beam can pass through the lens group 123 to realize scanning imaging. Generally, the structure formed by the scanning actuator 121 and the fiber optic cantilever 122 can be called: a fiber optic scanner.

[0049] As Figure 2a shown, in the embodiment of this application, through the movement of the fast and slow axes, the movement trajectory of the fiber optic light output end forms a scanning surface 230, and after passing through the corresponding lens group 123, it is converted into an imaging plane 240 (when the imaging is on a planar carrier, the image formed is planar. It should be noted that in other embodiments of the present invention, the image formed after passing through the lens group 123 can correspond to the surface of the imaging carrier, that is, it can change with the shape of the carrier surface as long as the imaging is clear).

[0050] For the convenience of description and to make it easy for those skilled in the art to understand the solution of this application, it should be noted that the optical imaging lens group in this application (such as the lens group 123 shown in Figure 2a ), as the eyepiece, through the action of this optical imaging lens group, can convert the scanning curved surface 230 into an imaging plane 240 (in actual application, the light transmission direction is: from the scanning curved surface 230 to the imaging plane 240).

[0051] Furthermore, it should be noted that in the projection field, the image corresponding to the imaging end is a planar image, and the corresponding planar image carrier can be, for example, a projection screen, a curtain, the ground, a glass surface, or a wall surface, etc. The image corresponding to the light source end is a curved surface image, that is, an arc-shaped scanning surface scanned by an optical fiber scanner or emitted by other image sources; in the use scenario of the camera field, the optical path is opposite to that in the projection field. Generally, the light source end corresponds to the object side for collecting image information, and the imaging end generally corresponds to the image side obtained by collecting and imaging.

[0052] Optical Imaging Lens Group

[0053] Please refer to Figure 2b . The optical imaging lens group in the embodiment of this application is composed of a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens that are coaxially arranged in sequence from the second side to the first side. The focal length of the first lens is positive or negative, and the focal lengths corresponding to the second lens to the sixth lens are positive, negative, positive, negative, and positive respectively. It should be noted that in the embodiment of the present invention, by reasonably optimizing the positive and negative properties of the focal lengths of the six coaxial lenses of the optical imaging lens group, the optical power of the system can be reasonably dispersed, the aberration generated by the lens can be reduced, the purpose of correcting various aberrations can be achieved, and clear imaging of the image-side curved surface can be realized.

[0054] Furthermore, there is the following ratio relationship between the minimum negative lens in the optical imaging lens group and the total focal length of the optical imaging lens group: 0.4 ≤ |f 最小负 / f 总 | ≤ 0.55, where f 最小负 is the focal length of the minimum negative lens, and f 总 is the total focal length of the optical imaging lens group. It should be noted that by limiting the ratio relationship between the focal length of the minimum negative lens among the multiple lenses and the total focal length of the optical imaging lens group, the optical power of the entire optical imaging lens group system can be reasonably dispersed and configured, thereby strengthening the correction of various aberrations and further ensuring the imaging quality of the optical imaging lens group.

[0055] Further optionally, in some embodiments of the present invention, the third lens, the fifth lens, and the sixth lens are all cemented lenses combined with positive lenses and negative lenses. Among them, the refractive index of the positive lens in the third lens and the fifth lens is less than that of the negative lens, and the refractive index of the positive lens in the sixth lens is greater than that of the negative lens. It should be noted that the fact that the refractive index of the positive lens in the third lens and the fifth lens is less than that of the negative lens can effectively eliminate spherical aberration and chromatic aberration during the imaging process. The fact that the refractive index of the positive lens in the sixth lens is greater than that of the negative lens is used to balance the field curvature of the system, thereby ensuring the imaging quality.

[0056] Further optionally, in some embodiments of the present invention, the third lens, the fifth lens, and the sixth lens satisfy at least any one of the following conditions: the refractive index difference between the negative lens and the positive lens in the third lens is 0.14 to 0.45; the refractive index difference between the negative lens and the positive lens in the fifth lens is 0.05 to 0.18; the refractive index difference between the positive lens and the negative lens in the sixth lens is 0.18 to 0.5. It should be noted that by setting the refractive index difference between the negative lens and the positive lens in the third lens and the fifth lens within a relatively preferred range, spherical aberration and chromatic aberration during the imaging process can be further eliminated. At the same time, by setting the refractive index difference between the positive lens and the negative lens in the sixth lens within a relatively preferred range, it is used to balance the field curvature of the system and further improve the imaging quality.

[0057] Further optionally, in some embodiments of the present invention, the positive lens in the sixth lens is closer to the first side than the negative lens. It should be noted that after the light rays emitted from the curved surface image are diverged and converged by multiple lenses, the positive lens corresponding to the sixth lens converges the diverged light rays, which can ensure that the light rays converge in the same plane, and at the same time eliminate spherical aberration and chromatic aberration during the imaging process, ensuring the imaging quality.

[0058] Further optionally, in some embodiments of the present invention, the average refractive index of the negative lenses of the optical imaging lens group is 1.693 to 1.85. It should be noted that by limiting the refractive index of the negative lenses in the optical imaging group through an optimized design, the dispersion coefficient of the corresponding lenses can be reasonably controlled to improve the imaging quality and ensure that the optical imaging lens group has a large field of view angle. It should be noted that the average refractive index of the negative lenses here refers to the average value of the refractive indices of the negative lenses in the first lens, the second lens, and the fourth lens in the optical imaging lens group, as well as the refractive indices of the sub-lenses that are negative lenses in the third lens, the fifth lens, and the sixth lens.

[0059] Further optionally, refer to Figure 2c, in some embodiments of the present invention, the second side corresponds to the curved surface image at the light source end, and optionally, the curved surface image is configured by a fiber optic scanner. The surface of the second side of the optical imaging lens group is concave. It should be noted that the surface of the second side of the optical imaging lens group is concave, and the curved surface image and the concave surface of the second side face in the same direction, which can enable the lens closest to the curved surface image to well adapt to the curved surface image, facilitating the reception of light with a large viewing angle, thereby more comprehensively and fully capturing information from the curved surface image. It should be emphasized that the uniqueness of the optical imaging lens group provided by the embodiments of the present application lies in its ability to correct and clearly image the curved surface image corresponding to the light source end on the second side (i.e., on the first side).

[0060] Further optionally, in some embodiments of the present invention, the achromatic aberration ability Z of the cemented lens n is represented by the following formula:

[0061] where n is 3, 5, 6, and Z n represents the achromatic aberration ability of the nth lens, and f n_1 and f n_2 represent the focal lengths of the positive lens and the negative lens corresponding to the cemented lens; Ab n_1 and Ab n_2 represent the Abbe numbers of the positive lens and the negative lens corresponding to the cemented lens; the achromatic aberration ability Z3 of the third lens is -0.167 to -0.07, the achromatic aberration ability Z5 of the fifth lens is -0.856 to -0.457, and the achromatic aberration ability Z6 of the sixth lens is -0.606 to -0.227. It should be noted that the closer the achromatic aberration ability of the cemented lens is to 0, the higher the ability of the cemented lens to eliminate chromatic aberration. In this example, the third lens and the fifth lens are used to eliminate spherical aberration and chromatic aberration during imaging. Further, the achromatic aberration ability of the sixth lens is used to balance the system field curvature, thereby ensuring the imaging quality.

[0062] Further, in a possible implementation manner, the connection method between the multiple lenses can be an interval connection or they can be bonded together by an adhesive method, which will be determined according to the actual application needs and is not limited here.

[0063] Further optionally, in a possible implementation manner, multiple lenses are all made of plastic or glass. It should be noted that lenses made of plastic can effectively reduce production costs. Compared with glass materials, the cost of plastic lenses is one-twentieth to one-tenth of that of glass materials. Therefore, it is very conducive to low-cost mass production. In addition, lenses made of plastic can usually be injection-molded, with low processing difficulty and can be easily processed into various aspherical surface structures. At the same time, plastic materials can also reduce the overall weight of the lens, which is beneficial to its lightweight product design. When using glass materials, the refractive index of glass materials is higher and wider, which has advantages in correcting lens aberrations. The coefficient of thermal expansion of glass materials is much smaller, which is beneficial to precise assembly. In addition, due to the characteristics of glass itself, such as high temperature resistance, ultraviolet resistance, acid and alkali resistance, etc., the service life and performance stability of the lens group have strong advantages. Of course, it should be emphasized that in other embodiments of the present invention, it is not limited to the two materials of plastic and glass provided in the embodiments of the present invention, and it can also be other materials capable of making lenses.

[0064] Example 1

[0065] Figure 3 FIG. 7 is a schematic structural diagram of an optical imaging lens group provided in Embodiment 1. The optical imaging lens group includes six lenses arranged in sequence along the optical axis direction, that is, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens that are coaxial in sequence from the second side to the first side. It should be noted that the focal lengths of the first lens to the sixth lens in the optical imaging lens group of this embodiment are negative, positive, negative, positive, negative, and positive respectively.

[0066] Further, the second side of the optical imaging lens group in this embodiment corresponds to the curved surface image 01 at the light source end. The numerical aperture (NA) of the optical imaging lens group is 0.27 mm, the total focal length is 1.578 mm, the exit pupil diameter is 0.74 mm, the working distance is 0.4 mm, and the full field of view angle is 36 degrees. It should be noted that with reference to Figure 2c , the working distance in the embodiments of this specification refers to the distance between the concave surface on the second side of the optical mirror group and the curved surface image on the optical axis.

[0067] In the embodiments of this specification, the optical imaging lens group further includes a diaphragm, and the diaphragm can be located on the first side of the optical imaging lens group. Among them, the side of the optical imaging lens group close to the diaphragm is a convex surface, that is to say, the side of a sub-lens corresponding to the sixth lens (i.e., the positive lens L6_2 in this embodiment) close to the diaphragm is a convex surface. Further, the distance d between the side of the positive lens L6_2 corresponding to the sixth lens close to the diaphragm and the diaphragm on the optical axis is 0.1 mm. It should be noted that in the embodiments of this application, when the side of the positive lens L6_2 corresponding to the sixth lens close to the diaphragm is a concave surface, the distance between the side of the positive lens L6_2 corresponding to the sixth lens close to the diaphragm and the diaphragm on the optical axis refers to the maximum distance between the concave surface and the diaphragm on the optical axis. When the side of the positive lens L6_2 corresponding to the sixth lens close to the diaphragm is a convex surface, the distance between the side of the positive lens L6_2 corresponding to the sixth lens close to the diaphragm and the diaphragm on the optical axis refers to the minimum distance between the convex surface and the diaphragm on the optical axis.

[0068] In this embodiment, the following ratio relationship exists between the minimum negative lens in the optical imaging lens group and the total focal length of the optical imaging lens group: f 最小负 / f 总 =-0.4. It should be noted that in the embodiments of this specification, the first lens to the sixth lens respectively correspond to lenses L1 to L6. Among them, the third lens (L3), the fifth lens (L5), and the sixth lens (L6) are all cemented lenses combined with positive lenses and negative lenses. The third lens L3 includes a negative lens L3_1 and a positive lens L3_2, the fifth lens L5 includes a positive lens L5_1 and a negative lens L5_2, and the sixth lens L6 includes a negative lens L6_1 and a positive lens L6_2. f 最小负 is the focal length of the minimum negative lens (i.e., the negative lens in the sixth lens in this embodiment), and f 总 is the total focal length of the optical imaging lens group. In addition, in the embodiments of this specification, the minimum negative lens in the optical imaging lens group refers to the minimum negative lens among the single lenses (such as the first lens, the second lens, and the fourth lens) and the sub-lenses corresponding to the cemented lenses (such as the third lens, the fifth lens, and the sixth lens). In some alternative embodiments, the order of the positive lens and the negative lens corresponding to the third lens L3 and the fifth lens L5 distributed along the optical axis can be adjusted. For example, the order of the negative lens L3_1 and the positive lens L3_2 in the third lens L3 can be interchanged. Another example is that the order of the positive lens L5_1 and the negative lens L5_2 in the fifth lens L5 can be interchanged. The content regarding the definition of the minimum negative lens and the adjustable distribution order of the positive lens and the negative lens corresponding to the third lens and the fifth lens is applicable to all embodiments of this specification, and will not be elaborated in other embodiments.

[0069] The relationship parameters between the focal lengths of each lens and the total focal length of the lens in this embodiment are shown in Table 1:

[0070] Table 1 Relationship parameter table between the focal lengths of each lens and the total focal length of the lens in this embodiment

[0071]

[0072]

[0073] Furthermore, in the embodiment of the present invention, the preferred parameters of the curvature radius, thickness parameter, refractive index, and Abbe number of each lens in the optical imaging lens group for imaging the curved surface image 01 are shown in Table 2:

[0074] Table 2 Structural parameters of the optical imaging lens group in the first embodiment

[0075] Surface Lens Serial Number Surface Shape Radius of Curvature Thickness Refractive Index of Material Abbe Number Curved Surface Image 01 - 0.4 1 L1 Spherical Surface -1.20 1.00 2.00 25.40 2 -2.36 0.10 3 L2 Spherical Surface -4.31 1.07 1.77 49.60 4 -2.26 0.10 5 L3_1 Spherical Surface -27.57 0.40 1.95 17.90 6 L3_2 Spherical Surface 3.60 1.37 1.50 81.60 7 -4.62 0.10 8 L4 Spherical Surface 3.80 1.28 1.98 21.60 9 -97.39 0.22 10 L5_1 Spherical Surface 1.96 1.53 1.77 49.60 11 L5_2 Spherical Surface -3.60 0.50 1.95 18.40 12 0.79 0.45 13 L6_1 Spherical Surface -1.91 0.50 1.50 81.60 14 L6_2 Spherical Surface 3.00 0.77 2.00 25.40 15 -5.00 0.10 Diaphragm Infinity 5.00 Plane Image Infinity

[0076] It should be noted that Table 2 shows the detailed structural data of the optical imaging lens group in the first embodiment. Among them, the units of the curvature radius, thickness, and focal length are all millimeters, and the surface order of 1-15 represents the surface from the second side to the first side; the optical surface with an infinite curvature radius in the imaging plane refers to a plane. According to the content of Table 2, in the cemented lenses in this example, the refractive index difference between the negative lens L3_1 and the positive lens L3_2 of the third lens L3 is 0.45, the refractive index difference between the negative lens L5_2 and the positive lens L5_1 of the fifth lens L5 is 0.18, and the difference between the positive lens L6_2 and the negative lens L6_1 of the sixth lens L6 is 0.5.

[0077] Furthermore, according to the content of Table 1 and Table 2, the achromatic aberration ability Z3 of the third lens L3 is -0.007, the achromatic aberration ability Z5 of the fifth lens L5 is -0.856, and the achromatic aberration ability Z6 of the sixth lens L6 is -0.227.

[0078] Furthermore, according to the content of Table 2, the average refractive index of the negative lenses in the optical imaging lens group is 1.85.

[0079] Furthermore, after testing, when using the above optical imaging lens group to project the image light corresponding to the scanning surface, its optical transfer function curve is as Figure 4 shown, the field curvature distortion curve is as Figure 5 shown, and the lateral chromatic aberration curve is as Figure 6 shown; among them, the optical transfer function curve (Modulation Transfer Function, MTF) represents the comprehensive resolution level of an optical system, the field curvature distortion curve represents the F-Tan(theta) distortion magnitude value (percentage) under different field angles, and the lateral chromatic aberration curve represents the chromatic aberration magnitude in the direction perpendicular to the axial direction.

[0080] From Figures 4 - 6It can be observed that the imaging resolution is good within the full field of view of the optical imaging lens group in the first embodiment, and the distortion and chromatic aberration of the optical system are small. Therefore, the optical imaging lens group can clearly image the scanned curved surface image of the fiber scanner, and all have good imaging effects.

[0081] Of course, in practical applications, the optical imaging lens group may further include a display element, a housing, etc. The display element can be arranged on the first side of the optical imaging lens group, and the optical imaging lens group can be installed in the housing, that is, the curved surface image formed by scanning an image source (such as a fiber scanner) can be imaged on a plane to achieve clear imaging.

[0082] Example 2

[0083] Figure 7 FIG. 10 is a schematic structural diagram of an optical imaging lens group provided for the second embodiment. The optical imaging lens group includes six lenses arranged in sequence along the optical axis direction, that is, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens that are coaxial in sequence from the second side to the first side. It should be noted that the focal lengths corresponding to the first lens to the sixth lens in the optical imaging lens group of this embodiment are positive, positive, negative, positive, negative, and positive respectively.

[0084] Further, the second side of the optical imaging lens group in this embodiment corresponds to the curved surface image 01 at the light source end. The numerical aperture (NA) of the lens of the optical imaging lens group is 0.27 mm, the total focal length is 1.586 mm, the exit pupil diameter is 0.9 mm, the working distance is 0.35 mm, and the full field of view angle is 36 degrees.

[0085] In the embodiment described in this specification, the optical imaging lens group further includes a diaphragm. The diaphragm can be located on the first side of the optical imaging lens group. Among them, the side of the optical imaging lens group close to the diaphragm is concave, that is, the side of a sub-lens corresponding to the sixth lens (that is, the positive lens L6_2 in this embodiment) close to the diaphragm is concave. Further, the distance d between the side of the positive lens L6_2 corresponding to the sixth lens close to the diaphragm and the diaphragm on the optical axis is 0.16 mm.

[0086] In this embodiment, the following ratio relationship exists between the minimum negative lens in the optical imaging lens group and the total focal length of the optical imaging lens group: f 最小负 / f 总 =-0.49.

[0087] The relationship parameters between the focal lengths of each lens and the total focal length of the lens in this embodiment are shown in Table 3:

[0088] Table 3 Relationship parameter table between the focal lengths of each lens and the total focal length of the lens in this embodiment

[0089]

[0090] Furthermore, in the embodiments of the present invention, the preferred parameters of the curvature radius, thickness parameter, refractive index, and Abbe number of each lens in the optical imaging lens group for imaging the curved surface image 01 are shown in Table 4:

[0091] Table 4 Structural parameters of the optical imaging lens group in the second embodiment

[0092] Surface Lens Serial Number Surface Shape Radius of Curvature Thickness Refractive Index of Material Abbe Number Curved Surface Image 01 - 0.35 1 L1 Spherical Surface -1.20 1.98 1.74 44.90 2 -1.95 0.10 3 L2 Spherical Surface 14.27 1.35 1.62 60.30 4 -2.80 0.44 5 L3_1 Spherical Surface -2.37 0.50 1.76 27.60 6 L3_2 Spherical Surface 3.40 1.55 1.62 60.30 7 -4.96 0.10 8 L4 Spherical Surface 4.46 2.00 1.74 44.90 9 80.61 0.10 10 L5_1 Spherical Surface 2.17 1.73 1.70 48.90 11 L5_2 Spherical Surface -5.96 0.79 1.75 37.30 12 0.79 0.46 13 L6_1 Spherical Surface 10.41 0.50 1.57 42.30 14 L6_2 Spherical Surface 0.94 0.89 1.75 34.00 15 12.85 0.16 Diaphragm Infinity 5.00- Plane Image Infinity

[0093] It should be noted that Table 4 shows the detailed structural data of the optical imaging lens group in the second embodiment. Among them, the units of the curvature radius, thickness, and focal length are all millimeters, and the surfaces 1-15 represent the surfaces from the second side to the first side in sequence; the optical surface with an infinite curvature radius in the imaging plane refers to a plane. According to the content of Table 2, in the cemented lenses in this example, the refractive index difference between the negative lens L3_1 and the positive lens L3_2 of the third lens L3 is 0.14, the refractive index difference between the negative lens L5_2 and the positive lens L5_1 of the fifth lens L5 is 0.05, and the difference between the positive lens L6_2 and the negative lens L6_1 of the sixth lens L6 is 0.18.

[0094] Furthermore, according to the content of Table 3 and Table 4, the achromatic aberration correction ability Z3 of the third lens L3 is -0.163, the achromatic aberration correction ability Z5 of the fifth lens L5 is -0.457, and the achromatic aberration correction ability Z6 of the sixth lens L6 is -0.421.

[0095] Furthermore, according to the content of Table 4, the average refractive index of the negative lenses in the optical imaging lens group is 1.693.

[0096] Furthermore, after testing, when using the above optical imaging lens group to project the image light corresponding to the scanning surface, its optical transfer function curve is as shown in Figure 8 shown, the field curvature distortion curve is as shown in Figure 9 shown, and the lateral chromatic aberration curve is as shown in Figure 10 shown; among them, the optical transfer function curve (Modulation Transfer Function, MTF) represents the comprehensive resolution level of an optical system, the field curvature distortion curve represents the F-Tan(theta) distortion magnitude value (percentage) under different field angles, and the lateral chromatic aberration curve represents the magnitude of chromatic aberration in the direction perpendicular to the axial direction.

[0097] From Figures 8 - 10 observation, it can be seen that the imaging resolution of the optical imaging lens group in the second embodiment is good within the full field of view, and the distortion and chromatic aberration of the optical system are small. Therefore, the optical imaging lens group can clearly image the scanned curved surface image of the fiber scanner and all have good imaging effects.

[0098] Of course, in practical applications, the optical imaging lens group may further include a display element, a housing, etc. The display element may be disposed on the first side of the optical imaging lens group, and the optical imaging lens group may be installed in the housing, that is, a curved surface image formed by scanning an image source (such as an optical fiber scanner) can be imaged on a plane to achieve clear imaging.

[0099] Example 3

[0100] Figure 11 FIG. 5 is a schematic structural diagram of an optical imaging lens group provided in Embodiment 3. The optical imaging lens group includes six lenses sequentially arranged along the optical axis direction, that is, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens that are coaxial from the second side to the first side in sequence. It should be noted that the focal lengths corresponding to the first lens to the sixth lens in the optical imaging lens group of this embodiment are positive, positive, negative, positive, negative, and positive respectively.

[0101] Further, the second side of the optical imaging lens group in this embodiment corresponds to the curved surface image 01 at the light source end. The numerical aperture (NA) of the lens of the optical imaging lens group is 0.27 mm, the total focal length is 1.6 mm, the exit pupil diameter is 0.9 mm, the working distance is 0.35 mm, and the full field of view angle is 36 degrees.

[0102] In the embodiment of this specification, the optical imaging lens group further includes a diaphragm. The diaphragm may be located on the first side of the optical imaging lens group. Among them, the side surface of the optical imaging lens group close to the diaphragm is concave, that is, the side surface of a sub-lens corresponding to the sixth lens (that is, the positive lens L6_2 in this embodiment) close to the diaphragm is concave. Further, the distance d between the side surface of the positive lens L6_2 corresponding to the sixth lens close to the diaphragm and the diaphragm on the optical axis is 0.23 mm.

[0103] In this embodiment, there is the following ratio relationship between the minimum negative lens in the optical imaging lens group and the total focal length of the optical imaging lens group: f 最小负 / f 总 =-0.55.

[0104] The relationship parameters between the focal lengths of each lens and the total focal length of the lens in this embodiment are shown in Table 5:

[0105] Table 5 Relationship parameter table between the focal lengths of each lens and the total focal length of the lens in this embodiment

[0106]

[0107] Further, in the embodiment of the present invention, the preferred parameters of the curvature radius, thickness parameter, refractive index, and Abbe number of each lens when the optical imaging lens group images the curved surface image 01 are shown in Table 6:

[0108] Table 6 Structural Parameters of the Optical Imaging Lens Group in Embodiment 3

[0109]

[0110]

[0111] It should be noted that Table 6 shows the detailed structural data of the optical imaging lens group in Embodiment 3. Among them, the units of the radius of curvature, thickness, and focal length are all millimeters, and the surfaces 1-15 represent the surfaces from the second side to the first side in sequence; the optical surface with an infinite radius of curvature in the imaging plane refers to a plane. According to the content of Table 6, in the cemented lenses in this example, the refractive index difference between the negative lens L3_1 and the positive lens L3_2 of the third lens L3 is 0.22, the refractive index difference between the negative lens L5_2 and the positive lens L5_1 of the fifth lens L5 is 0.05, and the difference between the positive lens L6_2 and the negative lens L6_1 of the sixth lens L6 is 0.27.

[0112] Furthermore, according to the content of Table 5 and Table 6, the achromatic aberration ability Z3 of the third lens L3 is -0.117, the achromatic aberration ability Z5 of the fifth lens L5 is -0.584, and the achromatic aberration ability Z6 of the sixth lens L6 is -0.606.

[0113] Furthermore, according to the content of Table 6, the average refractive index of the negative lenses in the optical imaging lens group is 1.76.

[0114] Furthermore, after testing, when projecting the image light corresponding to the scanning surface using the above optical imaging lens group, the optical transfer function curve is as shown in Figure 12 shown, the field curvature distortion curve is as shown in Figure 13 shown, and the lateral chromatic aberration curve is as shown in Figure 14 shown; among them, the optical transfer function curve (Modulation Transfer Function, MTF) represents the comprehensive resolution level of an optical system, the field curvature distortion curve represents the F-Tan(theta) distortion magnitude value (percentage) under different field angles of view, and the lateral chromatic aberration curve represents the magnitude of chromatic aberration in the direction perpendicular to the axial direction.

[0115] From Figures 12 - 14 observation, it can be seen that the imaging resolution of the optical imaging lens group in Embodiment 3 is good within the full field of view, and the distortion and chromatic aberration of the optical system are small. Therefore, the optical imaging lens group can clearly image the scanning surface image of the fiber scanner, and all have good imaging effects.

[0116] Of course, in practical applications, the optical imaging lens group may further include a display element, a housing, etc. The display element may be disposed on the first side of the optical imaging lens group, and the optical imaging lens group may be installed in the housing, so that a curved image formed by scanning an image source (such as a fiber optic scanner) can be imaged on a plane to achieve clear imaging.

[0117] Scanning Display Device

[0118] The aforementioned optical imaging lens group can cooperate with a fiber optic scanner (or a corresponding fiber optic scanning module) to form the scanning display device in the embodiments of the present application (as shown in Figure 1a , 1b ), the optical imaging lens group is disposed on the light output optical path of the fiber optic scanner. Among them, the second side of the optical imaging lens group faces the light output direction of the fiber optic scanner scanning. The preferred method is that the optical imaging lens group is coaxial with the central optical axis of the fiber optic scanner. Of course, the structure and general principle of the fiber optic scanner can be referred to the corresponding content in the foregoing Figure 1a , 1b , and will not be elaborated here too much.

[0119] In addition, in a possible implementation manner, the present application further provides an application of the above scanning display device, that is, the above scanning display device is configured in the projection field, specifically configured for in-vehicle projection. It can not only be configured at relevant positions such as on the external vehicle body or in the head-up display in the vehicle, but also can be configured inside the vehicle for projection display, and is specifically set flexibly according to the display requirements of in-vehicle projection.

[0120] In some embodiments, the scanning display device can be applied to a vehicle, and the vehicle includes but is not limited to an automobile, a motorcycle, an electric bicycle, a balance bike, a scooter, etc. In some embodiments, the in-vehicle projection system can also be applied to other tools with transportation capabilities, such as an aircraft, a ship, a wheelchair, etc. Taking an automobile as a specific example, the optical imaging module of the scanning display device can be disposed at the car door, the front of the vehicle or the rear of the vehicle to project an image onto the ground around the vehicle body. It should be noted that the image corresponding to the imaging end is a plane image, and the corresponding plane image carrier can be, for example, a projection screen, a curtain, the ground or a glass surface, etc. It should be noted that in the specific application of the scanning display device, the number of scanning display devices can be one group or multiple groups. When the scanning display devices are located at different positions of the carrier (such as a vehicle), the specifications of the fiber optic scanner, the distribution and parameters of each lens in the optical imaging lens group can be adaptively adjusted according to the specific scenario.

[0121] In summary, in the embodiments of the present application, by defining the focal length of the lens on the first side of the optical imaging lens group and the distance between the surface of the lens and the diaphragm on the optical axis, the optical imaging lens group can receive appropriate light in the curved surface image, realizing clear imaging of the image-side curved surface; by reasonably optimizing the focal lengths of the six coaxial lenses of the optical imaging lens group, the optical power of the system can be reasonably dispersed, the aberration generated by the lens can be reduced, and the purpose of correcting various aberrations can be achieved, realizing clear imaging of the image-side curved surface; by defining the ratio relationship between the minimum negative lens focal length of the plurality of lenses and the total focal length of the optical imaging lens group, the imaging quality of the optical imaging lens group is further ensured; by configuring the above optical imaging lens group in a fiber scanner, a miniaturized and lightweight scanning display device is formed, and by configuring and applying the scanning display device in the field of vehicle-mounted projection, the requirements of large viewing angle, high resolution and low distortion of vehicle-mounted projection can be achieved.

[0122] The above are only the preferred specific embodiments of the present application. Each embodiment is only used to illustrate the technical solution of the present application rather than to limit the present application. Any technical solution that can be obtained by those skilled in the art through logical analysis, reasoning or effective experiments according to the concept of the present application should be within the scope of the present application.

[0123] The embodiments in the present application are all described in a progressive manner. The same or similar parts between the embodiments can be referred to each other. Each embodiment focuses on the differences from other embodiments.

[0124] In various embodiments of the present disclosure, the expressions "first", "second", "the first" or "the second" used may modify various components without regard to order and / or importance, but these expressions do not limit the corresponding components. The above expressions are only configured for the purpose of distinguishing an element from other elements.

Claims

1. An optical imaging lens group, characterized in that, The optical imaging lens group includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens that are coaxially arranged in sequence from the second side to the first side. The focal length of the first lens is positive or negative, and the focal lengths of the second lens to the sixth lens are positive, negative, positive, negative, and positive respectively.

2. The optical imaging lens group according to claim 1, wherein The ratio between the minimum negative lens in the optical imaging lens group and the total focal length of the optical imaging lens group is as follows: 0.4 ≤ |f 最小负 / f 总 | ≤ 0.55, where f 最小负 is the focal length of the minimum negative lens, and f 总 is the total focal length of the optical imaging lens group.

3. The optical imaging lens group according to claim 2, characterized in that, The third lens, the fifth lens, and the sixth lens are all cemented lenses combined with a positive lens and a negative lens. The refractive index of the positive lens in the third lens and the fifth lens is less than that of the negative lens, and the refractive index of the positive lens in the sixth lens is greater than that of the negative lens.

4. The optical imaging lens group according to claim 3, characterized in that, The third lens, the fifth lens, and the sixth lens satisfy at least any one of the following conditions: The refractive index difference between the negative lens and the positive lens in the third lens is 0.14 to 0.45; The refractive index difference between the negative lens and the positive lens in the fifth lens is 0.05 to 0.18; The refractive index difference between the positive lens and the negative lens in the sixth lens is 0.18 to 0.

5.

5. The optical imaging lens group according to claim 3, wherein, The positive lens in the sixth lens is closer to the first side than the negative lens.

6. The optical imaging lens group according to any one of claims 1-5, characterized in that, The average refractive index of the negative lenses in the optical imaging lens group is 1.693 to 1.

85.

7. The optical imaging lens group according to any one of claims 1-5, characterized in that, The second side corresponds to the curved surface image of the light source end. The curved surface image is formed by the configuration of the fiber optic scanner, and the surface of the second side of the optical imaging lens group is concave.

8. The optical imaging lens group according to any one of claims 1-5, characterized in that, The achromatic aberration correction ability Z3 of the third lens is -0.167 to -0.07, the achromatic aberration correction ability Z5 of the fifth lens is -0.856 to -0.457, and the achromatic aberration correction ability Z6 of the sixth lens is -0.606 to -0.

227.

9. A scanning display device, characterized in that, It includes a fiber optic scanner and the optical imaging lens group according to any one of the preceding claims 1 to 8. The fiber optic scanner is used to scan and emit the light of the image to be displayed, and the optical imaging lens group is used to magnify and project the scanning surface corresponding to the light emitted by the fiber optic scanner; Wherein, the fiber optic scanner includes an actuator and an optical fiber fixed on the actuator. The part of the optical fiber exceeding the actuator forms an optical fiber cantilever, and the optical fiber cantilever performs two-dimensional scanning under the drive of the actuator.

10. An application of the scanning display device as described in claim 9, characterized in that, The scanning display device is configured in the field of vehicle-mounted displays.

Images