Optical imaging lens, scanning display device and near-eye display device

Abstract

The embodiment of the application discloses an optical imaging lens, a scanning display device and a near-eye display device, and relates to the technical field of scanning display. The optical imaging lens can reasonably disperse the optical power of the system, slow down the aberration generated by the lens, achieve the purpose of correcting various aberrations, and realize clear imaging of the image surface on the basis of improving the field of view by reasonably optimizing the focal length and surface structure of the related lenses in the eight coaxial lenses of the optical imaging lens. The combination of the aspherical lens and the spherical lens and the reasonable use of the single lens and the cemented lens further ensure the large field of view of the optical imaging lens, strengthen the correction of various optical aberrations, realize clear imaging, and at the same time, further reduce the volume and weight of the optical imaging lens, so that the overall structure of the optical imaging lens can be more compact, and the production demand of miniaturization of the lens product is met.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of scanning display, in particular to an optical imaging lens, a scanning display device and a near-eye display device. BACKGROUND

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

[0003] However, in the existing scanning display imaging system, there are high processing difficulty, high mass production cost, poor imaging quality, small field of view angle and the inability to be miniaturized, which limits the market promotion and application of the scanning display imaging technology. Especially when the scanning display imaging is applied to the near-eye display scenario, it cannot meet the performance requirements of high resolution in the near-eye display due to the influence of imaging effect and field of view angle, thereby hindering the development of the near-eye display to the consumer market. SUMMARY

[0004] The purpose of the present application is to provide an optical imaging lens, a scanning display device and a near-eye display device to meet the requirements of large field of view angle, high imaging quality and miniaturization in the near-eye display scenario.

[0005] The optical imaging lens provided by the embodiments of the present application comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens and an eighth lens arranged in sequence from a first side to a second side and coaxially, wherein the focal lengths of the first lens, the second lens, the third lens and the sixth lens are negative, positive, positive and positive respectively.

[0006] Further optionally, in the preferred embodiments of the present application, the first lens, the second lens, the third lens, the fourth lens, the sixth lens and the eighth lens are all spherical lenses.

[0007] The fifth lens and the seventh lens are both aspherical lenses.

[0008] Further optionally, in the preferred embodiments of the present application, the fourth lens and the sixth lens are both spherical cemented lenses.

[0009] Further optionally, in the preferred embodiments of the present application, the fourth lens and the sixth lens each comprise two sub-lenses.

[0010] Further optionally, in the preferred embodiments of the present application, the two sub-lenses of the fourth lens are arranged coaxially from the first side to the second side and have positive and negative focal lengths respectively.

[0011] The two sub-lenses of the sixth lens are arranged on the same optical axis from the first side to the second side, and the corresponding focal length positive and negative are negative and positive respectively.

[0012] Further optionally, in the preferred embodiment of the present application, the second side surface of the sub-lens of the fourth lens close to the fifth lens is a concave surface.

[0013] The first side surface of the fifth lens is a concave surface.

[0014] Further optionally, in the preferred embodiment of the present application, the focal lengths of the fourth lens, the fifth lens, the seventh lens and the eighth lens are negative, positive, positive and positive respectively.

[0015] The sub-lens of the fourth lens close to the fifth lens has the following relationship with the optical imaging lens group: 0.8≤|f 4-2 / f 总 |≤1.5, wherein the f 4-2 is the focal length of the sub-lens of the fourth lens close to the fifth lens, and the f 总 is the total focal length of the optical imaging lens group.

[0016] The present application also provides a scanning display device, which comprises an optical fiber scanner and the optical imaging lens group, the optical fiber scanner is used for scanning and emitting light of an image to be displayed, and the optical imaging lens group is used for magnifying and imaging a corresponding scanning surface of the light emitted by the optical fiber scanner and projecting the corresponding scanning surface.

[0017] The optical fiber scanner comprises an actuator and an optical fiber fixed on the actuator, a part of the optical fiber beyond the actuator forms an optical fiber cantilever, and the optical fiber cantilever performs two-dimensional scanning under the driving of the actuator.

[0018] The present application also provides a near-eye display device, which is used as a head-mounted augmented reality device and comprises at least a near-eye display module and the scanning display device.

[0019] The present application also provides a near-eye display device, which is used as a head-mounted virtual reality device and comprises at least a near-eye display module and the scanning display device.

[0020] The technical solutions in the embodiments of the present application can achieve the following technical effects:

[0021] In the embodiments of the present application, by optimizing the focal length and surface structure of part of the eight coaxial lenses in the optical imaging lens group, the optical power of the system can be reasonably dispersed, the aberration generated by the lens can be slowed down, the purpose of correcting various aberrations can be achieved, and clear imaging of the curved surface on the image side can be realized on the basis of improving the field of view.

[0022] Further, by reasonably combining a certain number of lenses, the overall structure of the optical imaging lens group is more compact, meeting the production needs of miniaturized mass production of lens products; by combining the use of aspherical lenses and spherical lenses, and by reasonably using single lenses and cemented lenses, the correction of various optical aberrations is further strengthened, clear imaging is realized, and at the same time, the volume and weight of the optical imaging lens group are further reduced.

[0023] Other features and advantages of the present application will be set forth in the following description, and in part will become apparent from the description, or can be learned by practice of the technology of the present application. The objects and other advantages of the present application can be achieved and obtained by the structures and / or processes specifically pointed out in the specification, claims and drawings. BRIEF DESCRIPTION OF DRAWINGS

[0024] Other features, objects and advantages of the present application will become more apparent from the following detailed description of non-limiting embodiments made with reference to the accompanying drawings:

[0025] Figure 1a 、 1b is a structural schematic diagram of an illustrative scanning display system;

[0026] Figure 2 is a schematic diagram of the scanning output of the optical fiber scanner provided in the embodiments of the present application;

[0027] Figure 3 is a structural schematic diagram of an optical imaging lens group provided in Embodiment One of the present application;

[0028] Figure 4 is an MTF curve diagram of the optical imaging lens group in Embodiment One of the present application;

[0029] Figure 5 is a field curvature distortion curve diagram of the optical imaging lens group in Embodiment One of the present application;

[0030] Figure 6 is an axial chromatic aberration diagram of the optical imaging lens group in Embodiment One of the present application.

[0031] Figure 7 is a structural schematic diagram of an optical imaging lens group provided in Embodiment Two of the present application;

[0032] Figure 8is a MTF curve diagram of the optical imaging lens set in Embodiment Two of the present application;

[0033] Figure 9 is a field curvature distortion curve diagram of the optical imaging lens set in Embodiment Two of the present application;

[0034] Figure 10 is a sagittal chromatic aberration diagram of the optical imaging lens set in Embodiment Two of the present application;

[0035] Figure 11 is a structural schematic diagram of an optical imaging lens set provided in Embodiment Three of the present application;

[0036] Figure 12 is a MTF curve diagram of the optical imaging lens set in Embodiment Three of the present application;

[0037] Figure 13 is a field curvature distortion curve diagram of the optical imaging lens set in Embodiment Three of the present application;

[0038] Figure 14 is a sagittal chromatic aberration diagram of the optical imaging lens set in Embodiment Three of the present application;

[0039] Figure 15 is a structural schematic diagram of an optical imaging lens set provided in Embodiment Four of the present application;

[0040] Figure 16 is a MTF curve diagram of the optical imaging lens set in Embodiment Four of the present application;

[0041] Figure 17 is a field curvature distortion curve diagram of the optical imaging lens set in Embodiment Four of the present application;

[0042] Figure 18 is a sagittal chromatic aberration diagram of the optical imaging lens set in Embodiment Four of the present application;

[0043] Figure 19 is a structural schematic diagram of an optical imaging lens set provided in Embodiment Five of the present application;

[0044] Figure 20 is a MTF curve diagram of the optical imaging lens set in Embodiment Five of the present application;

[0045] Figure 21 is a field curvature distortion curve diagram of the optical imaging lens set in Embodiment Five of the present application;

[0046] Figure 22 is a sagittal chromatic aberration diagram of the optical imaging lens set in Embodiment Five of the present application.

[0047] Icon: 100-processor; 110-laser group; 120-fiber scanning module; 130-transmission fiber; 140-light source modulation circuit; 150-scanning driving circuit; 160-combining unit; 121-scanning actuator; 121a-slow axis; 121b-fast axis; 122-fiber cantilever; 123-mirror group; 124-scanner package shell; 125-fixing member; 230-scanning curved surface; 240-imaging plane; 11-first lens; 12-second lens; 13-third lens; 14-fourth lens; 141, 142-fourth sub-lens; 15-fifth lens; 16-sixth lens; 161, 162-sixth sub-lens; 17-seventh lens; 18-eighth lens; 01-diaphragm; 02-scanning curved surface; 31-first lens; 32-second lens; 33-third lens; 34-fourth lens; 341, 342-fourth sub-lens; 35-fifth lens; 36-sixth lens; 361, 362-sixth sub-lens; 37-seventh lens; 38-eighth lens; 03-diaphragm; 04-scanning curved surface; 51-first lens; 52-second lens; 53-third lens; 54-fourth lens; 541, 542-fourth sub-lens; 55-fifth lens; 56-sixth lens; 561, 562-sixth sub-lens; 57-seventh lens; 58-eighth lens; 05-diaphragm; 06-scanning curved surface; 71-first lens; 72-second lens; 73-third lens; 74-fourth lens; 741, 742-fourth sub-lens; 75-fifth lens; 76-sixth lens; 761, 762-sixth sub-lens; 77-seventh lens; 78-eighth lens; 07-diaphragm; 08-scanning curved surface; 91-first lens; 92-second lens; 93-third lens; 94-fourth lens; 941, 942-fourth sub-lens; 95-fifth lens; 96-sixth lens; 961, 962-sixth sub-lens; 97-seventh lens; 98-eighth lens; 09-diaphragm; 10-scanning curved surface. DETAILED DESCRIPTION

[0048] The application will be further described below in conjunction with the drawings and examples. It should be understood that the specific examples described herein are intended to be illustrative only and are not intended to limit the scope of the application. In addition, it should be noted that only the parts of the drawings that are pertinent to the relevant application are shown for the sake of convenience.

[0049] Illustrative scanning display system

[0050] For the current scanning display imaging, it can be realized by Micro-Electro-Mechanical System (MEMS) or Fiber Scanning Display (FSD) device. The FSD scheme is a new type of scanning display imaging method, which realizes the scanning output of the image through the fiber scanner. In order to enable those skilled in the art to clearly understand the scheme of the present application, the brief principle of fiber scanning imaging and the corresponding system are described below.

[0051] As shown in Figure 1a , it is an illustrative scanning display system in the present application, which mainly includes:

[0052] The processor 100, the laser group 110, the fiber scanning module 120, the transmission fiber 130, the light source modulation circuit 140, the scanning drive circuit 150 and the beam combining unit 160. Among them,

[0053] The processor 100 can be a Graphics Processing Unit (GPU), a Central Processing Unit (CPU) or other chips or circuits with control function and image processing function, which is not specifically limited here.

[0054] 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 contains multiple monochromatic lasers, which respectively emit light beams of different colors. Figure 1a As can be seen from Figure 1a , the laser group 110 can specifically use Red (R), Green (G) and Blue (B) lasers. The light beams emitted by each laser in the laser group 110 are combined into a laser beam by the beam combining unit 160 and coupled into the transmission fiber 130.

[0055] 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.

[0056] The light beam outputted by the fiber scanner acts on a pixel position on the medium surface and forms a light spot on the pixel position, thus realizing scanning of the pixel position. Under the driving of the fiber scanner, the output end of the transmission fiber 130 sweeps according to a certain scanning track, so that the light beam moves to the corresponding pixel position. In the actual scanning process, the light beam outputted by the transmission fiber 130 will form a light spot with corresponding image information (such as color, gray scale or brightness) at each pixel position. In a frame of time, the light beam traverses each pixel position at a high enough speed to complete scanning of a frame of image. Due to the "visual residual" feature of human eye observation, the human eye cannot perceive the movement of the light beam at each pixel position, but sees a complete frame of image.

[0057] With reference to the foregoing Figure 1b , the specific structure of the fiber scanning module 120 is shown, which includes a scanning actuator 121, a fiber cantilever 122, a lens group 123, a scanner packaging shell 124 and a fixing member 125. The scanning actuator 121 is fixed in the scanner packaging shell 124 through the fixing member 125, and the transmission fiber 130 extends to form the fiber cantilever 122 (also referred to as a scanning fiber) at the front end of the scanning actuator 121. In operation, the scanning actuator 121 vibrates along a vertical direction (parallel to the Y axis in the coordinate system in the foregoing description, which is also referred to as a first direction in the present application) along its slow axis 121a (also referred to as a first actuating part) and vibrates along a horizontal direction (parallel to the X axis in the coordinate system in the foregoing description, which is also referred to as a second direction in the present application) along its fast axis 121b (also referred to as a second actuating part) under the driving of a scanning driving signal. Under the driving of the scanning actuator 121, the front end of the fiber cantilever 122 sweeps in two dimensions according to a preset track and emits a light beam, and the emitted light beam can pass through the lens group 123 to realize scanning imaging. Generally, the structure composed of the scanning actuator 121 and the fiber cantilever 122 can be referred to as a fiber scanner. Figure 1a 、 1b Figure 1a 、 1b

[0058] As shown in Figure 2 ​​As shown in this embodiment, the motion trajectory of the optical fiber output end forms a scanning surface 230 through the movement of the fast and slow axes. After passing through the corresponding lens group 123, it is converted into an imaging plane 240 (when imaging is performed on a planar carrier, the image is a plane; 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 image is clear). When applied to near-eye display devices such as augmented reality (AR) devices, the imaging plane 240 is coupled into the waveguide as the entrance pupil of the waveguide for imaging so that the human eye can view it.

[0059] To facilitate description and enable those skilled in the art to easily understand the solution of this application, it should be noted that the optical imaging lens assembly in this application (such as...) Figure 2 The lens group 123 shown serves as an eyepiece. Through the action of this optical imaging lens group, the scanning surface 230 can be converted into an imaging plane 240 (in practical applications, the direction of light transmission is from the scanning surface 230 to the imaging plane 240). Therefore, the side of the optical imaging lens group corresponding to the imaging plane 240 is referred to as the first side, and the side of the optical imaging lens group corresponding to the scanning surface 230 is referred to as the second side. In the following description, "first side" and "second side" will be used as references to describe the embodiment of the optical imaging lens group. Furthermore, in the description of the subsequent embodiments, such as for a certain lens in the optical imaging lens group, "the first side surface of the Xth lens" refers to the surface of the Xth lens facing the first side.

[0060] It should be further noted that in the field of projection, the image corresponding to the first side is a planar image, and the corresponding planar image carrier can be such as a projection screen, a screen, or a wall. The image corresponding to the second side is a curved image, that is, an arc-shaped scanning surface scanned by a fiber optic scanner or emitted by other image sources. In the application scenario of the camera field, the optical path is reversed in the field of projection. The first side generally corresponds to the object side that collects image information, and the second side generally corresponds to the image side that is captured and formed.

[0061] Optical imaging lens

[0062] The optical imaging lens in the embodiments of the present application comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens and an eighth lens arranged in sequence on the same optical axis from the first side to the second side, wherein the focal lengths of the first lens, the second lens, the third lens and the sixth lens are negative, positive, positive and positive respectively. It should be noted that by arranging a reasonable number of lenses and limiting the focal lengths of the first lens to the third lens and the sixth lens, the optical power of the system can be reasonably dispersed, the aberration generated by the lens can be slowed down, the purpose of correcting various aberrations can be achieved, and clear imaging of the curved surface of the image can be realized on the basis of improving the field of view. In addition, it should be emphasized that limiting the focal lengths of the third lens and the sixth lens to be positive can strengthen the convergence ability of the curved image to balance the aberration.

[0063] Further, in the embodiments of the present application, preferably, the focal lengths of the fourth lens, the fifth lens, the seventh lens and the eighth lens are negative, positive, positive and positive respectively. It should be emphasized that in other embodiments of the present application, the positive and negative of the focal lengths of the fourth lens, the fifth lens, the seventh lens and the eighth lens are not limited as in the embodiments of the present application, which can be positive or negative.

[0064] Further preferably, in the embodiments provided by the present application, the first lens, the second lens, the third lens, the fourth lens, the sixth lens and the eighth lens are all spherical lenses; the fifth lens and the seventh lens are all aspherical lenses. Moreover, the fourth lens and the sixth lens are both spherical cemented lenses. It should be noted that by reasonably configuring and using aspherical lenses and spherical lenses for the eight lenses, and by reasonably using single lenses and cemented lenses, the correction of various optical aberrations is further strengthened, and clear imaging is realized on the basis of expanding the field of view. It should be emphasized that by limiting the lens surface structure of a reasonable position and number (the fifth lens and the seventh lens) of lenses to an aspherical surface structure, more control variables can be obtained to reduce aberration and reasonably reduce the number of lenses, so as to help the miniaturization or micro-miniaturization of the optical imaging lens on the basis of improving the image display quality. In addition, the aspherical lens defined above refers to the first side surface and the second side surface being aspherical surface structures, and it can be understood that the entire or part of the optical effective area of the lens surface is aspherical.

[0065] Further specifically preferably, in the embodiments of the present application, the fourth lens and the sixth lens each have two sub-lenses as spherical cemented lenses. Preferably, the two sub-lenses of the fourth lens are arranged on the same optical axis from the first side to the second side, and the corresponding focal length positive and negative are positive and negative respectively; the two sub-lenses of the sixth lens are arranged on the same optical axis from the first side to the second side, and the corresponding focal length positive and negative are negative and positive respectively. It should be noted that by limiting the focal length positive and negative of the corresponding sub-lenses of the fourth lens and the sixth lens, the chromatic aberration and spherical aberration can be well eliminated, which is crucial for aberration correction of the entire imaging lens. Of course, in some embodiments of the present application, the focal length positive and negative of the two sub-lenses of the fourth lens can also be negative, and the two sub-lenses of the sixth lens can also be arranged as positive. It should be emphasized that in other embodiments of the present application, the number of corresponding sub-lenses of the fourth lens and the sixth lens is not limited to the number provided in the embodiments of the present application, and can also be other number of sub-lenses, such as 3 or 4, which can be flexibly set according to actual design needs.

[0066] Further, in the optical imaging lens provided by the embodiments of the present application, the second side surface of the sub-lens of the fourth lens close to the fifth lens is a concave surface, and the first side surface of the fifth lens is also a concave surface. It should be noted that by limiting the two opposite surfaces of the fourth lens and the fifth lens (i.e. the second side surface of the sub-lens of the fourth lens close to the fifth lens and the first side surface of the fifth lens) as concave surfaces, a larger image field curvature can be generated to cooperate with the curvature of the image surface, thereby achieving good aberration correction effect.

[0067] In addition, it should be further noted that the first side surface as a convex surface means that the first side surface forms a convex shape towards the first side direction of the optical imaging lens; the first side surface as a concave surface means that the first side surface forms a concave shape towards the first side direction of the optical imaging lens; the second side surface as a convex surface means that the second side surface forms a convex shape towards the second side direction of the optical imaging lens; and the second side surface as a concave surface means that the second side surface forms a concave shape towards the second side direction of the optical imaging lens.

[0068] Further, in some embodiments, the surface type of the lens is not entirely concave or convex, and the surface type of the lens can be a composite curved surface, or the near optical axis part is a curved surface and the edge part is not a curved surface; especially, when the lens surface is convex and the position of the convex surface is not defined, it means that the convex surface can be located at the near optical axis of the lens surface; similarly, when the lens surface is concave and the position of the concave surface is not defined, it means that the concave surface can be located at the near optical axis of the lens surface.

[0069] Further, the sub-lens of the fourth lens close to the fifth lens in the embodiments of the present application has the following relationship with the optical imaging lens: 0.8≤|f 4-2 / f 总|≤1.5, wherein, f 4-2 f is the focal length of the sub-lens of the fourth lens close to the fifth lens, 总 f is the total focal length of the optical imaging lens. It should be noted that by limiting the focal length ratio relationship of the sub-lens of the fourth lens close to the fifth lens and the total focal length of the optical imaging lens, the optical power of the system is reasonably dispersed and configured, thereby further strengthening the correction of various aberrations and improving the field of view angle and imaging quality. In addition, if the position of the lens focal length in the region is not defined in the embodiment, it means that the focal length of the lens can be the focal length of the lens at the near optical axis. It should be emphasized that before the present application, the existing optical imaging lens for projection display cannot balance the imaging quality and large field of view, that is, the imaging quality is usually reduced when the field of view is improved, and it is difficult to ensure the imaging quality while achieving a large field of view. The present application limits and reasonably configures the corresponding features (focal length, spherical and aspherical, single lens and cemented lens, and surface structure, etc.) of the corresponding lenses in the eight lenses, which realizes the high-quality output of imaging while improving the field of view and being small in size.

[0070] Further, in a possible implementation, the connection between the eight lenses can be spaced apart or bonded together, which will be determined according to the actual application needs, and is not limited here.

[0071] Further optionally, in a possible implementation, the first lens to the eighth lens are made of plastic or glass. It should be noted that the first lens to the eighth lens made of plastic can effectively reduce the production cost. Compared with glass material, the cost of plastic material lens is one-twentieth to one-tenth of the cost of glass material, so it is very beneficial to low-cost mass production. In addition, plastic material lenses can usually be injection molded, which has low processing difficulty and can be easily processed into various surface structures that meet the aspherical surface. At the same time, plastic material can also reduce the weight of the lens as a whole, which is beneficial to the lightweight product design. When using glass material, the refractive index of glass material is higher and wider, which has an advantage in correcting lens aberration. The expansion coefficient of glass material is much smaller, which is beneficial to precise assembly. In addition, due to the characteristics of glass such as high temperature resistance, ultraviolet resistance, and acid and alkali resistance, the service life and performance stability of the lens group have strong advantages. It should be emphasized that in other embodiments of the present application, the plastic and glass materials provided in the embodiments of the present application are not limited to the two materials, and other materials that can be used to make lenses can also be used.

[0072] It should be further explained that the optical imaging lens group disclosed in the embodiments of the present application can be optionally provided with at least one diaphragm, which can be located before the first lens (first side), between the lenses or after the eighth lens (second side). The diaphragm can be an aperture diaphragm or a field diaphragm, which can be used to reduce stray light and help improve image display quality.

[0073] Embodiment one

[0074] Figure 3 A structural schematic diagram of an optical imaging lens group provided by the embodiments of the present application is shown in FIG. 1. The optical imaging lens group comprises a first lens 11, a second lens 12, a third lens 13, a fourth lens 14, a fifth lens 15, a sixth lens 16, a seventh lens 17 and an eighth lens 18 arranged in sequence on the same optical axis from a first side (i.e., a side where a diaphragm 01 in FIG. 1 is located) to a second side (i.e., a side where a scanning curved surface 02 in FIG. 1 is located). Figure 3 Figure 3

[0075] In the embodiments, each two adjacent lenses among the first lens 11, the second lens 12, the third lens 13, the fourth lens 14, the fifth lens 15, the sixth lens 16, the seventh lens 17 and the eighth lens 18 has a gap, and the first lens 11, the second lens 12, the third lens 13, the fifth lens 15, the seventh lens 17 and the eighth lens 18 are six single non-bonding lenses. The fourth lens 14 is a bonded lens composed of two sub-lenses, and the corresponding two sub-lenses from the first side to the second side are a fourth sub-lens 141 and a fourth sub-lens 142, respectively. The sixth lens 16 is also a bonded lens composed of two sub-lenses, and the corresponding two sub-lenses from the first side to the second side are a sixth sub-lens 161 and a sixth sub-lens 162, respectively.

[0076] The focal lengths of the first lens 11 to the eighth lens 18 from the first side to the second side are negative, positive, positive, negative, positive, positive, positive and positive in sequence, wherein the focal lengths of the fourth sub-lens 141 and the fourth sub-lens 142 included in the fourth lens 14 are positive and negative, respectively, and the focal lengths of the sixth sub-lens 161 and the sixth sub-lens 162 included in the sixth lens 16 are negative and positive, respectively.

[0077] The first side surface and the second side surface of the first lens 11 are both concave at the near optical axis;

[0078] The first side surface of the second lens 12 is concave at the near optical axis, and the second side surface is convex.

[0079] The first side surface and the second side surface of the third lens 13 are both convex;

[0080] ​​The first side surface and the second side surface of the fourth sub-lens 141 in the fourth lens 14 are both convex, and the first side surface and the second side surface of the fourth sub-lens 142 are both concave;

[0081] The first side surface of the fifth lens 15 is concave at the near optical axis, and the second side surface is convex at the near optical axis;

[0082] The first side surface and the second side surface of the sixth sub-lens 161 in the sixth lens 16 are both concave, and the first side surface and the second side surface of the sixth sub-lens 162 are both convex;

[0083] The first side surface of the seventh lens 17 is convex at the near optical axis, and the second side surface is concave at the near optical axis;

[0084] The first side surface of the eighth lens 18 is convex, and the second side surface is concave at the near optical axis.

[0085] In the embodiment, the focal length of the fourth lens 14 in the optical imaging lens group satisfies the following relationship:

[0086] 0.8≤|f 4-2 / f 总 |≤1.5, wherein f 4-2 is the focal length of the sub-lens of the fourth lens 14 close to the fifth lens 15, that is, the focal length of the fourth sub-lens 142, and f 总 is the total focal length of the optical imaging lens group. It should be noted that the specific focal length values of each lens are shown in Table 1:

[0087] Table 1: Focal length parameter table of each lens in the optical imaging lens group

[0088] Lens Focal length Lens focal length / total lens focal length First lens 11 -2.86 -1.11 Second lens 12 7.17 2.78 Third lens 13 3.82 1.48 Fourth lens 14 -12.02 -4.66 Fourth sub-lens 141 3.9 1.51 Fourth sub-lens 142 -2.21 -0.86 Fifth lens 15 61.18 23.71 Sixth lens 16 40.01 15.51 Sixth sub-lens 161 -6.69 -2.59 Sixth sub-lens 162 11.05 4.28 Seventh lens 17 9.1 3.53 Eighth lens 18 64.08 24.84

[0089] The refractive index and the dispersion coefficient of the first lens 11, the fourth sub-lens 142, and the sixth sub-lens 161 in the optical imaging lens group satisfy the following conditions respectively:

[0090] The refractive index and the dispersion coefficient of the first lens 11 are 1.92 and 20.9 respectively; the refractive index and the dispersion coefficient of the fourth sub-lens 142 are 1.85 and 23.8 respectively, and the refractive index and the dispersion coefficient of the sixth sub-lens 161 are 1.92 and 20.9 respectively.

[0091] The total focal length of the optical imaging lens group is 2.58 mm, and the field of view angle is 28 degrees. The radius of curvature, thickness parameter, refractive index, and dispersion coefficient of each lens in the optical imaging lens group for imaging the scanning curved surface 02 are shown in Table 2:

[0092] Table 2: Structure parameters of the optical imaging lens group in Example 1

[0093]

[0094]

[0095] It is to be noted that Table 1 and Table 2 are detailed structure data of the optical imaging lens group of Example 1, wherein the units of the curvature radius, the thickness and the focal length are millimeters, and the surfaces 0-20 in Table 2 represent the surfaces from the first side to the second side in sequence; the optical surface with the curvature radius of "infinity" in the imaging plane means a plane.

[0096] Further, the conic coefficients and aspheric coefficients of the surfaces corresponding to the fifth lens 15 and the seventh lens 17 (both are aspheric lenses) are shown in Table 3 as follows:

[0097] Table 3 is the data of the conic coefficients and aspheric coefficients of the surfaces of the aspheric lenses in Example 1, wherein k is the conic coefficient in the aspheric curve equation, and A4 to A16 represent the 4th to 16th order aspheric coefficients of each surface.

[0098] Surface k A4 A6 A8 A10 A12 A14 A16 11 -7.5E-01 1.6E-01 -5.4E-02 6.4E-02 -4.9E-02 2.6E-02 -9.3E-03 2.9E-03 12 -1.2E+00 4.5E-04 -1.4E-03 1.1E-03 -1.8E-04 -1.1E-04 4.6E-05 -3.0E-06 16 -6.9E-01 -6.3E-03 -1.4E-03 -1.5E-04 8.3E-04 -5.2E-04 1.4E-04 -1.4E-05 17 -1.1E+00 -4.1E-02 2.5E-03 6.5E-03 -5.9E-03 2.4E-03 -4.6E-04 3.4E-05

[0099] Table 3 is the data of the conic coefficients and aspheric coefficients in Example 1, wherein k is the conic coefficient in the aspheric curve equation, and A4 to A16 represent the 4th to 16th order aspheric coefficients of each surface.

[0100] Further, when the image light corresponding to the scanning surface is projected by using the optical imaging lens group, the Modulation Transfer Function (MTF) curve is shown in Figure 4 , the field curvature distortion curve is shown in Figure 5 , and the axial chromatic aberration curve is shown in Figure 6 ; wherein the Modulation Transfer Function (MTF) curve represents the comprehensive resolution level of an optical system, the field curvature distortion curve represents the F-Tan(theta) distortion value (percentage) under different field angles, and the axial chromatic aberration curve represents the size of the chromatic aberration perpendicular to the axial direction.

[0101] It can be observed from Figures 4-6 that the imaging resolution of the optical imaging lens group of Example 1 is good in the full field of view, the optical system distortion and the chromatic aberration are small, so the optical imaging lens group can clearly image the scanning surface image of the fiber scanner, and all have good imaging effect.

[0102] Of course, in actual application, the optical imaging lens group can further include a display element and a housing, the display element can be arranged on the second side of the optical imaging lens group, and the optical imaging lens group can be installed in the housing, so that the curved surface image scanned by the image source (such as a fiber scanner) can be imaged on a plane carrier to achieve clear imaging.

[0103] Embodiment two

[0104] Figure 7 A structural schematic diagram of an optical imaging lens provided by an embodiment of the present application. The optical imaging lens comprises a first lens 31, a second lens 32, a third lens 33, a fourth lens 34, a fifth lens 35, a sixth lens 36, a seventh lens 37 and an eighth lens 38 arranged in sequence on an optical axis from a first side (i.e., a side on which a stop 03 in the optical imaging lens is located) to a second side (i.e., a side on which a scanning surface 04 in the optical imaging lens is located). Figure 7 Figure 7 The first lens 31, the second lens 32, the third lens 33, the fourth lens 34, the fifth lens 35, the sixth lens 36, the seventh lens 37 and the eighth lens 38 are arranged in sequence on the optical axis from the first side to the second side.

[0105] In the embodiment, there is a gap between each two adjacent lenses among the first lens 31, the second lens 32, the third lens 33, the fourth lens 34, the fifth lens 35, the sixth lens 36, the seventh lens 37 and the eighth lens 38, and the first lens 31, the second lens 32, the third lens 33, the fifth lens 35, the seventh lens 37 and the eighth lens 38 are six single non-bonding lenses. The fourth lens 34 is a bonded lens composed of two sub-lenses, and the corresponding two sub-lenses are a fourth sub-lens 341 and a fourth sub-lens 342 from the first side to the second side; the sixth lens 36 is also a bonded lens composed of two sub-lenses, and the corresponding two sub-lenses are a sixth sub-lens 361 and a sixth sub-lens 362 from the first side to the second side.

[0106] The focal lengths of the first lens 31 to the eighth lens 38 from the first side to the second side are negative, positive, positive, negative, positive, positive, positive and negative in sequence, wherein the focal lengths of the fourth sub-lens 341 and the fourth sub-lens 342 included in the fourth lens 34 are positive and negative respectively, and the focal lengths of the sixth sub-lens 361 and the sixth sub-lens 362 included in the sixth lens 36 are negative and positive respectively.

[0107] The first side surface and the second side surface of the first lens 31 are both concave at the near optical axis;

[0108] The first side surface of the second lens 32 is concave at the near optical axis, and the second side surface is convex.

[0109] The first side surface and the second side surface of the third lens 33 are both convex;

[0110] The first side surface and the second side surface of the fourth sub-lens 341 in the fourth lens 34 are both convex, and the first side surface and the second side surface of the fourth sub-lens 342 are both concave;

[0111] The first side surface of the fifth lens 35 is concave at the near optical axis, and the second side surface is convex at the near optical axis;

[0112] ​The first side surface of the sixth sub-lens 361 in the sixth lens 36 is a convex surface, the second side surface is a concave surface, and the first side surface and the second side surface of the sixth sub-lens 362 are both convex surfaces;

[0113] The first side surface of the seventh lens 37 is a convex surface at the near optical axis, and the second side surface is a concave surface at the near optical axis;

[0114] The first side surface of the eighth lens 38 is a convex surface, and the second side surface is a concave surface at the near optical axis.

[0115] In the embodiment, the focal length of the fourth lens 34 in the optical imaging lens group satisfies the following relationship:

[0116] 0.8≤|f 4-2 / f 总 |≤1.5, wherein f 4-2 is the focal length of the sub-lens of the fourth lens 34 close to the fifth lens 35, that is, the focal length of the fourth sub-lens 342, and f 总 is the total focal length of the optical imaging lens group. It should be noted that the specific focal length values of each lens are shown in Table 4:

[0117] Table 4: Focal length parameter table of each lens in the optical imaging lens group

[0118] Lens Focal length Lens focal length / total lens focal length First lens 31 -2.53 -0.99 Second lens 32 6.38 2.50 Third lens 33 3.61 1.41 Fourth lens 34 -12.10 -4.75 Fourth sub-lens 341 5.74 2.25 Fourth sub-lens 342 -3.01 -1.18 Fifth lens 35 -16.14 -6.33 Sixth lens 36 22.04 8.64 Sixth sub-lens 361 -15.40 -6.04 Sixth sub-lens 362 22.90 8.98 Seventh lens 37 6.01 2.36 Eighth lens 38 -23.16 -9.08

[0119] The refractive index and dispersion coefficient of the first lens 31, the fourth sub-lens 342, and the sixth sub-lens 361 in the optical imaging lens group satisfy the following conditions respectively:

[0120] The refractive index and dispersion coefficient of the first lens 31 are 1.95 and 17.9 respectively; the refractive index and dispersion coefficient of the fourth sub-lens 342 are 1.78 and 25.7 respectively, and the refractive index and dispersion coefficient of the sixth sub-lens 361 are 1.92 and 18.89 respectively.

[0121] The total focal length of the optical imaging lens group provided in the second embodiment of the application is 2.58mm, and the field of view angle is 28 degrees. The curvature radius, thickness parameter, refractive index, and dispersion coefficient of each lens in the optical imaging lens group for imaging the scanning curved surface 04 are shown in Table 5:

[0122] Table 5: Structure parameters of the optical imaging lens group in the second embodiment

[0123]

[0124] It should be noted that Table 4 and Table 5 are detailed structure data of the optical imaging lens group of Example 2, wherein the units of the curvature radius, the thickness and the focal length are millimeters, and the surfaces 0-20 in Table 5 represent the surfaces from the first side to the second side in sequence; the optical surface with the curvature radius of "infinity" in the imaging plane means a plane.

[0125] Further, the aspherical conic coefficients of the surfaces corresponding to the fifth lens 35 and the seventh lens 37 (both are aspherical lenses) are shown in Table 6 as follows:

[0126] Table 6: Conic coefficients and aspherical coefficients of the surfaces of the aspherical lenses in Example 2

[0127] Surface k A4 A6 A8 A10 A12 A14 A16 11 -9.83E-01 6.19E-02 -2.18E-02 -9.85E-04 3.42E-02 -5.23E-02 3.47E-02 -8.51E-03 12 -1.10E+00 -2.14E-02 1.43E-02 -1.15E-02 7.37E-03 -3.01E-03 6.84E-04 -6.44E-05 16 -9.81E-01 -1.45E-02 8.92E-03 -6.56E-03 4.10E-03 -1.64E-03 3.49E-04 -2.96E-05 17 -5.03E+00 -1.23E-03 -1.35E-02 1.48E-02 -1.04E-02 4.09E-03 -7.93E-04 5.82E-05

[0128] Table 6 is the conic coefficients and aspherical coefficients data in Example 2, wherein k is the conic coefficient in the aspherical curve equation, and A4 to A16 represent the 4th to 16th order aspherical coefficients of each surface.

[0129] Further, when the image light corresponding to the scanning surface is projected by using the optical imaging lens group, the Modulation Transfer Function (MTF) curve is shown in Figure 8 , the field curvature distortion curve is shown in Figure 9 , and the axial chromatic aberration curve is shown in Figure 10 ; wherein the Modulation Transfer Function (MTF) curve represents the comprehensive resolution level of an optical system, the field curvature distortion curve represents the F-Tan(theta) distortion size value (percentage) under different field angles, and the axial chromatic aberration curve represents the size of the chromatic aberration perpendicular to the axial direction.

[0130] It can be observed from Figures 8-10 that the imaging resolution of the optical imaging lens group of Example 2 is good in the full field of view, the optical system distortion and the chromatic aberration are small, so the optical imaging lens group can clearly image the scanning surface image of the fiber scanner, and all have good imaging effects.

[0131] Of course, in actual application, the optical imaging lens group can further include a display element and a shell, the display element can be arranged on the second side of the optical imaging lens group, and the optical imaging lens group can be installed in the shell, that is, the curved surface image scanned by the image source (such as a fiber scanner) can be imaged on a plane carrier to realize clear imaging.

[0132] Embodiment three

[0133] Figure 11 A structure diagram of an optical imaging lens group provided by the embodiment of the present application. The optical imaging lens group includes a first side (also referred to as a first surface), a second side (also referred to as a second surface), a first lens 31, a second lens 32, a third lens 33, a fourth lens 34, a fifth lens 35, a sixth lens 36 and a seventh lens 37.Figure 11 the side where the light barrier 05 is located in the first embodiment) to the second side (i.e., the side where the scanning surface 06 is located in the first embodiment) are sequentially arranged. Figure 11 The first lens 51, the second lens 52, the third lens 53, the fourth lens 54, the fifth lens 55, the sixth lens 56, the seventh lens 57, and the eighth lens 58 are sequentially arranged on the same optical axis.

[0134] In the first embodiment, each two adjacent lenses among the first lens 51, the second lens 52, the third lens 53, the fourth lens 54, the fifth lens 55, the sixth lens 56, the seventh lens 57, and the eighth lens 58 have a gap, and the first lens 51, the second lens 52, the third lens 53, the fifth lens 55, the seventh lens 57, and the eighth lens 58 are six single non-bonded lenses. The fourth lens 54 is a bonded lens composed of two sub-lenses, and the corresponding two sub-lenses from the first side to the second side are the fourth sub-lens 541 and the fourth sub-lens 542, respectively. The sixth lens 56 is also a bonded lens composed of two sub-lenses, and the corresponding two sub-lenses from the first side to the second side are the sixth sub-lens 561 and the sixth sub-lens 562, respectively.

[0135] The focal lengths of the first lens 51 to the eighth lens 58 from the first side to the second side are negative, positive, positive, negative, positive, positive, negative, and positive in sequence, wherein the focal lengths of the fourth sub-lens 541 and the fourth sub-lens 542 included in the fourth lens 54 are negative and negative, respectively, and the focal lengths of the sixth sub-lens 561 and the sixth sub-lens 562 included in the sixth lens 56 are positive and positive, respectively.

[0136] The first side surface and the second side surface of the first lens 51 are both concave at the near optical axis;

[0137] The first side surface and the second side surface of the second lens 52 are both convex.

[0138] The first side surface and the second side surface of the third lens 53 are both convex.

[0139] The first side surface of the fourth sub-lens 541 in the fourth lens 54 is concave at the near optical axis, and the second side surface is convex, and the first side surface and the second side surface of the fourth sub-lens 542 are both concave.

[0140] The first side surface of the fifth lens 55 is concave at the near optical axis, and the second side surface is convex at the near optical axis.

[0141] The first side surface of the sixth sub-lens 561 in the sixth lens 56 is convex, and the second side surface is concave, and the first side surface and the second side surface of the sixth sub-lens 562 are both convex.

[0142] The first side surface of the seventh lens 57 is convex at the near optical axis, and the second side surface is concave at the near optical axis.

[0143] The first side surface of the eighth lens 58 is convex, and the second side surface is concave at the near optical axis.

[0144] In the present embodiment, the focal length of the fourth lens 54 in the optical imaging lens satisfies the following relationship:

[0145] 0.8≤|f 4-2 / f 总 |≤1.5, wherein, f 4-2 is the focal length of the sub-lens of the fourth lens 54 close to the fifth lens 55, that is, the focal length of the fourth sub-lens 542, and f 总 is the total focal length of the optical imaging lens. It should be noted that the specific focal length value of each lens is shown in Table 7:

[0146] Table 7: Focal length parameter table of each lens in the optical imaging lens

[0147]

[0148]

[0149] The refractive index and dispersion coefficient of the first lens 51, the fourth sub-lens 542, and the sixth sub-lens 561 in the optical imaging lens satisfy the following conditions respectively:

[0150] The refractive index and dispersion coefficient of the first lens 51 are 1.96 and 19.4 respectively; the refractive index and dispersion coefficient of the fourth sub-lens 542 are 1.82 and 22.4 respectively, and the refractive index and dispersion coefficient of the sixth sub-lens 561 are 1.89 and 20.2 respectively.

[0151] The total focal length of the optical imaging lens provided in the third embodiment of the present application is 2.58 mm, and the field of view angle is 28 degrees. The curvature radius, thickness parameter, refractive index, and dispersion coefficient of each lens in the imaging of the scanning curved surface 06 are shown in Table 8:

[0152] Table 8: Structure parameter of the optical imaging lens in the third embodiment

[0153]

[0154] It should be noted that Table 7 and Table 8 are detailed structure data of the optical imaging lens in the third embodiment, wherein the units of the curvature radius, thickness, and focal length are all millimeters, and the surfaces 0-20 in Table 8 represent the surfaces from the first side to the second side in order; the optical surface with a curvature radius of "infinity" in the imaging plane means a plane.

[0155] Further, the conic coefficients and aspheric coefficients of the surfaces corresponding to the fifth lens 55 and the seventh lens 57 (both are aspheric lenses) are shown in Table 9:

[0156] Table 9: Conic and aspheric coefficients of the aspheric surfaces in Example 3

[0157] Surface k A4 A6 A8 A10 A12 A14 A16 11 -9.06E-01 2.82E-02 7.00E-02 -2.42E-02 4.35E-02 -5.16E-02 2.57E-02 -4.82E-03 12 -1.66E+00 -4.48E-02 1.66E-02 -8.28E-03 7.33E-03 -3.04E-03 6.71E-04 -6.89E-05 16 9.39E-02 2.62E-02 -1.25E-02 -4.29E-04 3.54E-03 -1.96E-03 4.82E-04 -4.90E-05 17 -1.43E+00 8.33E-02 1.40E-02 -1.08E-02 3.34E-03 1.23E-02 -8.69E-03 1.88E-03

[0158] Table 9: Conic and aspheric coefficients of the aspheric surfaces in Example 3, wherein k is the conic coefficient in the aspheric equation, and A4 to A16 are the 4th to 16th aspheric coefficients of each surface.

[0159] Further, when the image light corresponding to the scanning surface is projected by the optical imaging lens group, the Modulation Transfer Function (MTF) curve is as shown in Figure 12 , the field curvature distortion curve is as shown in Figure 13 , and the sagittal chromatic aberration curve is as shown in Figure 14 ; wherein the MTF curve represents the comprehensive resolution level of an optical system, the field curvature distortion curve represents the F-Tan(theta) distortion value (percentage) at different field angles, and the sagittal chromatic aberration curve represents the size of the chromatic aberration perpendicular to the axial direction.

[0160] As can be seen from Figures 12-14 , the optical imaging lens group of Example 3 has good imaging resolution in the full field of view, small optical system distortion and chromatic aberration, and thus can clearly image the scanning surface image of the fiber scanner, and all have good imaging effects.

[0161] Of course, in actual applications, the optical imaging lens group can further include a display element and a housing, and the display element can be arranged on the second side of the optical imaging lens group. The optical imaging lens group can be installed in the housing, so that the curved surface image scanned by the image source (such as a fiber scanner) can be imaged on a planar carrier to achieve clear imaging.

[0162] Embodiment four

[0163] Figure 15 A structural schematic diagram of an optical imaging lens group according to an embodiment of the present application is shown in FIG. 1. The optical imaging lens group includes a first lens 71, a second lens 72, a third lens 73, a fourth lens 74, a fifth lens 75, a sixth lens 76, a seventh lens 77, and an eighth lens 78 arranged in sequence on the same optical axis from a first side (i.e., the side where the stop 07 in Figure 15 is located) to a second side (i.e., the side where the scanning surface 08 in Figure 15 is located).

[0164] In the embodiment, there is a gap between each two adjacent lenses among the first lens 71, the second lens 72, the third lens 73, the fourth lens 74, the fifth lens 75, the sixth lens 76, the seventh lens 77 and the eighth lens 78, and the first lens 71, the second lens 72, the third lens 73, the fifth lens 75, the seventh lens 77 and the eighth lens 78 are six single non-bonded lenses. The fourth lens 74 is a bonded lens composed of two sub-lenses, and the corresponding two sub-lenses from the first side to the second side are the fourth sub-lens 741 and the fourth sub-lens 742 respectively; the sixth lens 76 is also a bonded lens composed of two sub-lenses, and the corresponding two sub-lenses from the first side to the second side are the sixth sub-lens 761 and the sixth sub-lens 762 respectively.

[0165] The focal lengths of the first lens 71 to the eighth lens 78 from the first side to the second side are negative, positive, positive, positive, positive, positive, negative and positive in turn, wherein the focal lengths of the fourth sub-lens 741 and the fourth sub-lens 742 included in the fourth lens 74 are positive and negative respectively, and the focal lengths of the sixth sub-lens 761 and the sixth sub-lens 762 included in the sixth lens 76 are negative and positive respectively.

[0166] The first side surface and the second side surface of the first lens 71 are both concave at the near optical axis;

[0167] The first side surface and the second side surface of the second lens 72 are both convex.

[0168] The first side surface of the third lens 73 is concave at the near optical axis, and the second side surface is convex;

[0169] The first side surface and the second side surface of the fourth sub-lens 741 in the fourth lens 74 are both convex, and the first side surface and the second side surface of the fourth sub-lens 742 are both concave;

[0170] The first side surface of the fifth lens 75 is concave at the near optical axis, and the second side surface is convex at the near optical axis;

[0171] The first side surface and the second side surface of the sixth sub-lens 761 in the sixth lens 76 are both concave, and the first side surface and the second side surface of the sixth sub-lens 762 are both convex;

[0172] The first side surface of the seventh lens 77 is convex at the near optical axis, and the second side surface is concave at the near optical axis;

[0173] The first side surface of the eighth lens 78 is convex, and the second side surface is concave at the near optical axis.

[0174] In the embodiment, the focal length of the fourth lens 74 in the optical imaging lens group satisfies the following relationship:

[0175] 0.8≤|f 4-2 / f总 |≤1.5, wherein, f 4-2 f is the focal length of the sub-lens of the fourth lens 74 close to the fifth lens 75, that is, the focal length of the fourth sub-lens 742, f 总 f is the total focal length of the optical imaging lens. It should be noted that the specific focal length value of each lens is shown in Table 10:

[0176] Table 10: Focal length parameter table of each lens in the optical imaging lens

[0177] Lens Focal length Lens focal length / total lens focal length First lens 71 -1.98 -0.70 Second lens 72 3.01 1.06 Third lens 73 12.15 4.29 Fourth lens 74 19.90 7.03 Fourth sub-lens 741 3.66 1.29 Fourth sub-lens 742 -2.83 -1.00 Fifth lens 75 4.38 1.55 Sixth lens 76 11.41 4.03 Sixth sub-lens 761 -17.03 -6.02 Sixth sub-lens 762 9.21 3.25 Seventh lens 77 -2.48 -0.87 Eighth lens 78 1.81 0.64

[0178] The refractive index and dispersion coefficient of the first lens 71, the fourth sub-lens 742, and the sixth sub-lens 761 in the optical imaging lens satisfy the following conditions respectively:

[0179] The refractive index and dispersion coefficient of the first lens 71 are 1.78 and 21.4 respectively; the refractive index and dispersion coefficient of the fourth sub-lens 742 are 1.9 and 27.1 respectively, and the refractive index and dispersion coefficient of the sixth sub-lens 761 are 1.83 and 21.6 respectively.

[0180] The total focal length of the optical imaging lens provided in the fourth embodiment of the present application is 2.58 mm, and the field of view angle is 28 degrees. The curvature radius, thickness parameter, refractive index, and dispersion coefficient of each lens in the imaging of the scanning curved surface 08 are shown in Table 11:

[0181] Table 11: Structure parameters of the optical imaging lens in the fourth embodiment

[0182]

[0183]

[0184] It should be noted that Table 10 and Table 11 are detailed structure data of the optical imaging lens in the fourth embodiment, wherein the units of curvature radius, thickness, and focal length are all millimeters, and the surfaces 0-20 in Table 11 represent the surfaces from the first side to the second side in order; the optical surface with a curvature radius of "infinity" in the imaging plane means a plane.

[0185] Further, the conic coefficients and aspheric conic coefficients of the surfaces corresponding to the fifth lens 75 and the seventh lens 77 (both are aspheric lenses) are shown in Table 12:

[0186] Table 12: Conic coefficients and aspheric conic coefficients of different lens surfaces in the fourth embodiment

[0187] Surface k A4 A6 A8 A10 A12 A14 A16 11 -9.69E-01 6.51E-02 3.83E-02 -2.30E-02 4.47E-02 -5.37E-02 2.70E-02 -4.99E-03 12 -1.81E+00 -2.00E-02 1.53E-02 -7.08E-03 7.45E-03 -3.20E-03 6.67E-04 -6.24E-05 16 -6.75E-01 5.42E-02 -2.09E-02 1.51E-03 4.48E-03 -2.00E-03 3.54E-04 -2.26E-05 17 -1.51E+00 2.09E-01 -1.20E-01 5.20E-02 1.77E-02 3.09E-04 -1.21E-02 3.86E-03

[0188] Table 12 is the conic coefficient and aspheric coefficient data in Example 4, wherein k is the conic coefficient in the aspheric equation, and A4 to A16 represent the 4th to 16th order aspheric coefficients of each surface.

[0189] Further, when the image light corresponding to the scanning surface is projected by the optical imaging lens group, the optical transfer function curve is as shown in Figure 16 , the field curvature distortion curve is as shown in Figure 17 , and the axial chromatic aberration curve is as shown in Figure 18 ; wherein 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 value (percentage) at different field angles, and the axial chromatic aberration curve represents the size of the chromatic aberration perpendicular to the axial direction.

[0190] It can be observed from Figures 16-18 that the optical imaging lens group of Example 4 has good imaging resolution in the full field of view, small optical system distortion and chromatic aberration, and thus can clearly image the scanning surface image of the fiber scanner, and all have good imaging effects.

[0191] Of course, in actual applications, the optical imaging lens group can also include display elements, housings, etc., the display elements can be arranged on the second side of the optical imaging lens group, and the optical imaging lens group can be installed in the housing, so that the curved surface image scanned by the image source (such as a fiber scanner) can be imaged on a flat carrier to achieve clear imaging.

[0192] Embodiment five

[0193] Figure 19 A structural schematic diagram of an optical imaging lens group according to an embodiment of the present application is provided. The optical imaging lens group includes a first lens 91, a second lens 92, a third lens 93, a fourth lens 94, a fifth lens 95, a sixth lens 96, a seventh lens 97, and an eighth lens 98 arranged in sequence on the same optical axis from the first side (i.e., the side where the diaphragm 09 in Figure 19 is located) to the second side (i.e., the side where the scanning curved surface 10 in Figure 19 is located).

[0194] In the embodiment, there is a gap between each two adjacent lenses among the first lens 91, the second lens 92, the third lens 93, the fourth lens 94, the fifth lens 95, the sixth lens 96, the seventh lens 97 and the eighth lens 98, and the first lens 91, the second lens 92, the third lens 93, the fifth lens 95, the seventh lens 97 and the eighth lens 98 are six single non-bonded lenses. The fourth lens 94 is a bonded lens composed of two sub-lenses, and the corresponding two sub-lenses from the first side to the second side are the fourth sub-lens 941 and the fourth sub-lens 942 respectively; the sixth lens 96 is also a bonded lens composed of two sub-lenses, and the corresponding two sub-lenses from the first side to the second side are the sixth sub-lens 961 and the sixth sub-lens 962 respectively.

[0195] The focal lengths of the first lens 91 to the eighth lens 98 from the first side to the second side are negative, positive, positive, positive, positive, positive, negative and positive in turn, wherein the focal lengths of the fourth sub-lens 941 and the fourth sub-lens 942 included in the fourth lens 94 are positive and negative respectively, and the focal lengths of the sixth sub-lens 961 and the sixth sub-lens 962 included in the sixth lens 96 are negative and positive respectively.

[0196] The first side surface and the second side surface of the first lens 91 are both concave at the near optical axis;

[0197] The first side surface and the second side surface of the second lens 92 are both convex.

[0198] The first side surface of the third lens 93 is concave at the near optical axis, and the second side surface is convex;

[0199] The first side surface and the second side surface of the fourth sub-lens 941 in the fourth lens 94 are both convex, and the first side surface and the second side surface of the fourth sub-lens 942 are both concave;

[0200] The first side surface of the fifth lens 95 is concave at the near optical axis, and the second side surface is convex at the near optical axis;

[0201] The first side surface and the second side surface of the sixth sub-lens 961 in the sixth lens 96 are both concave, and the first side surface and the second side surface of the sixth sub-lens 962 are both convex;

[0202] The first side surface of the seventh lens 97 is convex at the near optical axis, and the second side surface is concave at the near optical axis;

[0203] The first side surface of the eighth lens 98 is convex, and the second side surface is concave at the near optical axis.

[0204] In the embodiment, the focal length of the fourth lens 94 in the optical imaging lens group satisfies the following relationship:

[0205] 0.8≤|f 4-2 / f总 |≤1.5, wherein, f 4-2 f is the focal length of the sub-lens of the fourth lens 94 close to the fifth lens 95, that is, the focal length of the fourth sub-lens 942, f 总 f is the total focal length of the optical imaging lens. It should be noted that the specific focal length value of each lens is shown in Table 13:

[0206] Table 13: Focal length parameter table of each lens in the optical imaging lens

[0207]

[0208]

[0209] The refractive index and dispersion coefficient of the first lens 91, the fourth sub-lens 942, and the sixth sub-lens 961 in the optical imaging lens satisfy the following conditions respectively:

[0210] The refractive index and dispersion coefficient of the first lens 91 are 1.79 and 23 respectively; the refractive index and dispersion coefficient of the fourth sub-lens 942 are 1.72 and 24 respectively, and the refractive index and dispersion coefficient of the sixth sub-lens 961 are 1.77 and 21.8 respectively.

[0211] The total focal length of the optical imaging lens provided by the fifth embodiment of the present application is 2.58 mm, and the field of view angle is 28 degrees. The curvature radius, thickness parameter, refractive index, and dispersion coefficient of each lens in the imaging of the scanning curved surface 10 are shown in Table 14:

[0212] Table 14: Structure parameters of the optical imaging lens in the fifth embodiment

[0213]

[0214] It should be noted that Table 13 and Table 14 are detailed structure data of the optical imaging lens in the fifth embodiment, wherein the units of curvature radius, thickness, and focal length are all millimeters, and the surfaces 0-20 in Table 14 represent the surfaces from the first side to the second side; the optical surface with a curvature radius of "infinity" in the imaging plane means a plane.

[0215] Further, the conic coefficients and aspheric coefficients of the surfaces corresponding to the fifth lens 95 and the seventh lens 97 (both are aspheric lenses) are shown in Table 15:

[0216] Table 15: Conic coefficients and aspheric coefficients of the surface of the aspheric lens in the fifth embodiment

[0217] Surface k A4 A6 A8 A10 A12 A14 A16 11 -1.06E+00 8.34E-02 2.36E-02 -3.28E-02 5.08E-02 -5.02E-02 2.39E-02 -4.39E-03 12 -1.58E+00 -2.26E-02 1.38E-02 -8.06E-03 7.33E-03 -3.26E-03 7.23E-04 -6.72E-05 16 -5.11E-01 5.29E-02 -1.64E-02 -3.02E-04 4.32E-03 -1.84E-03 3.24E-04 -1.81E-05 17 -5.21E+00 1.35E-01 -7.26E-02 2.82E-02 -1.63E-03 2.82E-03 -3.58E-03 9.62E-04

[0218] Table 15 shows the conic coefficient and aspheric coefficient data in Example 5, where k is the conic coefficient in the aspheric curve equation, and A4 to A16 represent the 4th to 16th order aspheric coefficients of each surface.

[0219] Furthermore, tests showed that when the image light corresponding to the scanning surface is projected using the aforementioned optical imaging lens group, its optical transfer function curve is as follows: Figure 20 As shown, the field distortion curve is as follows: Figure 21 As shown, the vertical axis color difference curve is as follows: Figure 22 As shown; among them, the Modulation Transfer Function (MTF) curve represents the overall resolution level of an optical system, the Field Curve Distortion curve represents the F-Tan (theta) distortion magnitude (percentage) under different field angles, and the Vertical Chromatic Aberration curve represents the magnitude of chromatic aberration in the direction perpendicular to the axial direction.

[0220] Depend on Figures 20-22 Observations show that the optical imaging lens group in Example 5 has good imaging resolution and small optical system distortion and chromatic aberration across the entire field of view. Therefore, the optical imaging lens group can clearly image the scanning surface image of the fiber optic scanner and has good imaging effect.

[0221] Of course, in practical applications, the optical imaging lens assembly may also include a display element, a housing, etc. The display element can be set on the second side of the optical imaging lens assembly, and the optical imaging lens assembly can be installed in the housing. This allows the curved image formed by the image source (such as a fiber optic scanner) to be imaged onto a flat carrier, thus achieving clear imaging.

[0222] Scanning display device

[0223] The aforementioned optical imaging lens assembly can be used in conjunction with a fiber optic scanner (or a corresponding fiber optic scanning module) to constitute the scanning display device in the embodiments of this application (e.g., Figure 1a , 1b As shown, the optical imaging lens group is positioned on the output optical path of the fiber optic scanner. The first side of the optical imaging lens group faces the scanning output direction of the fiber optic scanner. Preferably, 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 found in the aforementioned... Figure 1a , 1b The corresponding content will not be elaborated on here.

[0224] Near-eye display device

[0225] In this application, the scanning display device can be further applied to a near-eye display device, and can be used in conjunction with a near-eye display module to form the near-eye display device in the embodiments of this application, for use as a head-mounted AR device (such as AR glasses). The scanning display device is disposed in the near-eye display module.

[0226] The near-eye display module may include: a light source, processing and control circuitry, a wearable frame structure, and a waveguide. The image beam output from the light source enters the scanning display device, where it is scanned by a fiber optic scanner and output to the optical display lens assembly. The scanning surface of the fiber optic scanner (see reference) Figure 3 The scan surface 02 and its corresponding Figure 2 The scanning surface 230 in the image is converted into an imaging plane after passing through the optical display lens group (see reference). Figure 2 The imaging plane 240 in the waveguide is coupled into the waveguide as the entrance pupil surface, and then coupled out through the waveguide to enter the human eye.

[0227] As another possible implementation, the scanning display device can be further combined with the near-eye display module to form the near-eye display device in the embodiments of this application, and used as a head-mounted VR device (such as a VR helmet / glasses). The scanning display device is disposed in the near-eye display module.

[0228] In this embodiment, by rationally optimizing the focal lengths of the eight coaxial lenses in the optical imaging lens group, the optical power of the system can be reasonably dispersed, aberrations generated by the lenses can be reduced, and the purpose of correcting various aberrations can be achieved. This results in clear imaging of the image surface while improving the field of view. By configuring a reasonable number of lenses, the overall structure of the optical imaging lens group is made more compact, meeting the production requirements for miniaturized mass production of lens products. By combining aspherical and spherical lenses, and by rationally using single lenses and cemented lenses, the correction of various optical aberrations is further enhanced, achieving clear imaging. At the same time, the size and weight of the optical imaging lens group are further reduced.

[0229] The above descriptions are merely preferred embodiments of this application. Each embodiment is only used to illustrate the technical solution of this application and is not intended to limit this application. Any technical solution that can be obtained by those skilled in the art through logical analysis, reasoning, or effective experiments based on the concept of this application should be within the scope of this application.

[0230] The various embodiments in this application are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

[0231] The expressions "first", "second", "the first", or "the second" used in various embodiments of the disclosure can modify various components regardless of order and / or importance, but the expressions do not limit the corresponding components. The above expressions are configured only for the purpose of distinguishing an element from other elements. For example, the first lens and the second lens represent different lenses, although both are lenses.

Claims

1. An optical imaging lens assembly, characterized in that, The optical imaging lens group consists of a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens arranged coaxially from the first side to the second side. The image corresponding to the first side of the optical imaging lens group is a planar image, and the image corresponding to the second side of the optical imaging lens group is a curved image. The curved image is an arc-shaped scanning surface scanned by a fiber optic scanner or emitted from another image source. The focal lengths of the first lens, the second lens, the third lens, and the sixth lens are negative, positive, positive, and positive, respectively. The fourth lens and the sixth lens are both cemented spherical lenses, and each includes two sub-lenses. The two sub-lenses of the fourth lens are arranged coaxially from the first side to the second side, and their corresponding focal lengths are positive and negative, respectively. The two sub-lenses of the sixth lens are also arranged coaxially from the first side to the second side, and their corresponding focal lengths are negative and positive, respectively.

2. The optical imaging lens assembly according to claim 1, characterized in that, The first lens, the second lens, the third lens, the fourth lens, the sixth lens, and the eighth lens are all spherical lenses; Both the fifth lens and the seventh lens are aspherical lenses.

3. The optical imaging lens assembly according to claim 2, characterized in that, The second side surface of the fourth lens, which is close to the sub-lens of the fifth lens, is concave. The first side surface of the fifth lens is concave.

4. The optical imaging lens assembly according to claim 2, characterized in that, The focal lengths of the fourth lens, the fifth lens, the seventh lens, and the eighth lens are negative, positive, positive, and positive, respectively. The sub-lens of the fourth lens closest to the fifth lens has the following relationship with the optical imaging lens group: 0.8 ≤ |f 4-2 / f 总 |≤1.5, where f 4-2 The focal length of the sub-lens of the fourth lens closest to the fifth lens, f 总 The total focal length of the optical imaging lens group is given.

5. A scanning display device, characterized in that, The invention includes a fiber optic scanner and an optical imaging lens group according to any one of claims 1 to 4, wherein the fiber optic scanner is used to scan and emit light to display an image, 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. The fiber optic scanner includes an actuator and an optical fiber fixed to the actuator. The portion of the optical fiber extending beyond the actuator forms an optical fiber cantilever, which performs two-dimensional scanning under the drive of the actuator.

6. A near-eye display device, characterized in that, The near-eye display device is used as a head-mounted augmented reality device, and includes at least a near-eye display module and a scanning display device according to claim 5, wherein the scanning display device is disposed in the near-eye display module.

7. A near-eye display device, characterized in that, The near-eye display device is used as a head-mounted virtual reality device, and includes at least a near-eye display module and a scanning display device according to claim 5, wherein the scanning display device is disposed in the near-eye display module.

Images