CN113568138A - Optical imaging lens group, scanning display device and near-to-eye display equipment - Google Patents

Optical imaging lens group, scanning display device and near-to-eye display equipment Download PDF

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CN113568138A
CN113568138A CN202110757268.XA CN202110757268A CN113568138A CN 113568138 A CN113568138 A CN 113568138A CN 202110757268 A CN202110757268 A CN 202110757268A CN 113568138 A CN113568138 A CN 113568138A
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lens
optical imaging
scanning
imaging lens
lens group
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CN113568138B (en
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不公告发明人
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Chengdu Idealsee Technology Co Ltd
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Chengdu Idealsee Technology Co Ltd
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    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B13/00Optical objectives specially designed for the purposes specified below
    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B13/00Optical objectives specially designed for the purposes specified below
    • G02B13/001Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras
    • G02B13/0015Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras characterised by the lens design
    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B13/00Optical objectives specially designed for the purposes specified below
    • G02B13/001Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras
    • G02B13/0015Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras characterised by the lens design
    • G02B13/002Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras characterised by the lens design having at least one aspherical surface
    • G02B13/0045Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras characterised by the lens design having at least one aspherical surface having five or more lenses
    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B13/00Optical objectives specially designed for the purposes specified below
    • G02B13/16Optical objectives specially designed for the purposes specified below for use in conjunction with image converters or intensifiers, or for use with projectors, e.g. objectives for projection TV
    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B13/00Optical objectives specially designed for the purposes specified below
    • G02B13/18Optical objectives specially designed for the purposes specified below with lenses having one or more non-spherical faces, e.g. for reducing geometrical aberration
    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B26/00Optical devices or arrangements for the control of light using movable or deformable optical elements
    • G02B26/08Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the direction of light
    • G02B26/10Scanning systems
    • G02B26/103Scanning systems having movable or deformable optical fibres, light guides or waveguides as scanning elements
    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/01Head-up displays
    • G02B27/0101Head-up displays characterised by optical features
    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/01Head-up displays
    • G02B27/017Head mounted
    • G02B27/0172Head mounted characterised by optical features
    • GPHYSICS
    • G03PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03BAPPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B21/00Projectors or projection-type viewers; Accessories therefor
    • G03B21/14Details

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Lenses (AREA)

Abstract

The embodiment of the application discloses an optical imaging lens group, a scanning display device and near-to-eye display equipment, and relates to the technical field of scanning display. The optical imaging lens group reasonably optimizes the focal lengths of six lenses with the same optical axis, can reasonably disperse the focal power of a system, slows down the aberration generated by the lenses, and achieves the aim of correcting various aberrations, thereby realizing clear imaging of an image side curved surface on the basis of improving the field angle; the refractive index, the dispersion coefficient and the surface type structure of the six lenses with the same optical axis are limited and optimized, so that the field angle and the imaging quality are further improved; the six coaxial lenses are limited and optimally designed to be aspheric surface-shaped structures and made of plastic materials, so that the imaging quality is further improved, the forming processing difficulty of the whole optical imaging lens group is reduced, and the mass production is favorably realized at low cost.

Description

Optical imaging lens group, scanning display device and near-to-eye display equipment
Technical Field
The application relates to the technical field of scanning display, in particular to an optical imaging lens group, a scanning display device and near-to-eye display equipment.
Background
Scanning display imaging is a new display technology, and can be used for various application scenes such as projection display, near-eye display and the like.
However, the existing scanning display imaging system has the disadvantages of high processing difficulty, high volume production cost, poor imaging quality, small viewing field angle and the like, so that the scanning display imaging technology is limited in the market popularization and application process, and particularly when the scanning display imaging is applied to a near-eye display scene, the scanning display imaging technology is limited by the influence of an imaging effect and a viewing field angle, so that the scanning display imaging technology cannot meet the performance requirement of high resolution in near-eye display at all times, and the development of the near-eye display to the consumer-grade market is hindered.
Disclosure of Invention
An object of the present application is to provide an optical imaging lens assembly, a scanning display device and a near-eye display device, so as to satisfy the requirements of large field angle, high imaging quality, easy processing and low cost in a near-eye display scene.
The embodiment of the application provides an optical imaging mirror group, optical imaging mirror group includes first lens, second lens, third lens, fourth lens, fifth lens and the sixth lens that is set up by first side to second side sharing optical axis in proper order, first lens extremely the focus that the sixth lens corresponds is positive, burden, just and burden respectively.
Optionally, each of the lenses satisfies the following relationship: 1<f1/f<2、6<f2/f<30、0.2<|f3/f|<1、1<f4/f<3、0.5<f5/f<1.5 and 1<|f6/f|<2.5;
Wherein f is1Is the focal length of the first lens, f2Is the focal length of the second lens, f3Is the focal length of the third lens, f4Is the focal length of the fourth lens, f5Is the focal length of the fifth lens, f6F is the focal length of the sixth lens element, and f is the focal length of the optical imaging lens group.
Optionally, each of the lenses further satisfies the following relationship:
1.5<n1<1.7,1.5<n2<1.7,1.6<n3<1.7,1.5<n4<1.6,1.45<n5<1.6,1.5<n6<1.7;
wherein n1 is a refractive index of the first lens, n2 is a refractive index of the second lens, n3 is a refractive index of the third lens, n4 is a refractive index of the fourth lens, n5 is a refractive index of the fifth lens, and n6 is a refractive index of the sixth lens.
Alternatively, the n1 is 1.59, the n2 is 1.53 or 1.64, the n3 is 1.67, the n4 is 1.52, the n5 is 1.53, the n6 is 1.53;
the abbe number of each of the lenses satisfies: the abbe number of the first lens is 29.9, the abbe number of the second lens is 56.1 or 22.4, the abbe number of the third lens is 19.3, the abbe number of the fourth lens is 52.1, the abbe number of the fifth lens is 55.0, and the abbe number of the sixth lens is 56.1.
Optionally, the first side surface of the sixth lens element is convex and the second side surface of the sixth lens element is concave at paraxial region.
Optionally, the first side surface of the third lens is concave at paraxial region and the second side surface of the third lens is convex; the first side surface of the fourth lens is a convex surface, and the second side surface of the fourth lens is a concave surface; the first side surface and the second side surface of the fifth lens are convex surfaces.
Optionally, the first side surface and the second side surface of each of the first lens to the sixth lens are aspheric surface-shaped structures;
the first lens to the sixth lens are all made of plastic;
the second side of the optical imaging lens group corresponds to a curved image, and the first side of the optical imaging lens group corresponds to a plane image.
The embodiment of the application also provides a scanning display device, which comprises an optical fiber scanner and the optical imaging lens group, wherein 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 amplifying, imaging and projecting a scanning surface corresponding to the light emitted by the optical fiber scanner;
the optical fiber scanner comprises an actuator and an optical fiber fixed on the actuator, wherein a part of the optical fiber, which exceeds the actuator, forms an optical fiber cantilever, and the optical fiber cantilever is driven by the actuator to perform two-dimensional scanning.
The embodiment of the application further provides near-eye display equipment, and the near-eye display equipment is used as head-mounted augmented reality equipment and at least comprises a near-eye display module and the scanning display device, wherein the scanning display device is arranged in the near-eye display module.
The embodiment of the application further provides near-eye display equipment, which is characterized in that the near-eye display equipment is used as head-mounted virtual reality equipment and at least comprises a near-eye display module and the scanning display device, and the scanning display device is arranged in the near-eye display module.
By adopting the technical scheme in the embodiment of the application, the following technical effects can be realized:
in the embodiment of the application, the focal lengths of six coaxial lenses of the optical imaging lens group are reasonably optimized, so that the focal power of the system can be reasonably dispersed, the aberration generated by the lenses is reduced, and the purpose of correcting various aberrations is achieved, thereby realizing clear imaging of the image side curved surface on the basis of improving the field angle.
Furthermore, the refractive index, the dispersion coefficient and the surface type structure of the six lenses with the same optical axis are limited and optimized, so that the field angle and the imaging quality are further improved; the six coaxial lenses are limited and optimally designed to be aspheric surface-shaped structures and made of plastic materials, so that the imaging quality is further improved, the forming processing difficulty of the whole optical imaging lens group is reduced, and the mass production is favorably realized at low cost.
Additional features and advantages of the application will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by the practice of the invention. The objectives and other advantages of the application may be realized and attained by the structure and/or processes particularly pointed out in the written description and claims hereof as well as the appended drawings.
Drawings
Other features, objects and advantages of the present application will become more apparent upon reading of the following detailed description of non-limiting embodiments thereof, made with reference to the accompanying drawings in which:
FIGS. 1a and 1b are schematic structural views of an illustrative scanning display system;
FIG. 2 is a schematic diagram of a scan output of a fiber scanner provided by an embodiment of the present application;
FIG. 3 is a schematic structural diagram of an optical imaging lens assembly according to an embodiment of the present application;
FIG. 4 is a MTF graph of an optical imaging lens assembly according to an embodiment of the present disclosure;
FIG. 5 is a graph of field curvature distortion of an optical imaging lens assembly in accordance with an embodiment of the present invention;
FIG. 6 is a diagram of axial chromatic aberration of an optical imaging lens assembly according to an embodiment of the present application;
FIG. 7 is a vertical axis chromatism chart of an optical imaging lens assembly according to an embodiment of the present application.
Fig. 8 is a schematic structural diagram of an optical imaging lens assembly according to a second embodiment of the present application;
FIG. 9 is a MTF graph of an optical imaging lens assembly according to a second embodiment of the present application;
FIG. 10 is a graph of field curvature distortion of an optical imaging lens assembly according to a second embodiment of the present application;
FIG. 11 is a diagram of axial chromatic aberration of the optical imaging lens assembly according to the second embodiment of the present application;
fig. 12 is a vertical axis chromatic aberration diagram of the optical imaging lens assembly in the second embodiment of the present application.
Icon: 100-a processor; 110-a laser group; 120-fiber scanning module; 130-a transmission fiber; 140-light source modulation circuit; 150-scan drive circuit; 160-beam combining unit; 121-a scanning actuator; 121 a-slow axis; 121 b-fast axis; 122-fiber cantilever; 123-mirror group; 124-scanner package; 125-a fastener; 230-scanning a curved surface; 240-imaging plane; 11-a first lens; 12-a second lens; 13-a third lens; 14-a fourth lens; 15-a fifth lens; 16-a sixth lens; 01-a diaphragm; 02-scanning a curved surface; 31-a first lens; 32-a second lens; 33-a third lens; 34-a fourth lens; 35-a fifth lens; 36-a sixth lens; 03-diaphragm; 04-scanning the curved surface.
Detailed Description
The present application will be described in further detail with reference to the following drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the relevant invention and not restrictive of the invention. It should be noted that, for convenience of description, only the portions related to the related invention are shown in the drawings.
Illustrative scanning display system
For current Scanning Display imaging, it can be realized by Digital Micromirror Device (DMD) or Fiber Scanning Display (FSD) Device. The FSD scheme is used as a novel scanning display imaging mode, and the scanning output of images is realized through an optical fiber scanner. In order to make the solution of the present application clearly understandable to those skilled in the art, the following provides a brief description of the principles of fiber scanning imaging and a corresponding system.
Fig. 1a is a schematic diagram of an illustrative scanning display system according to the present application, which mainly includes:
the optical fiber scanning device comprises a processor 100, a laser group 110, a fiber scanning module 120, a transmission fiber 130, a light source modulation circuit 140, a scanning driving circuit 150 and a beam combining unit 160. Wherein,
the processor 100 may be a Graphics Processing Unit (GPU), a Central Processing Unit (CPU), or other chips or circuits having a control function and an image Processing function, and is not limited in particular.
When the system works, the processor 100 may control the light source modulation circuit 140 to modulate the laser group 110 according to image data to be displayed, where the laser group 110 includes a plurality of monochromatic lasers, and the lasers emit light beams of different colors respectively. As shown in fig. 1, three-color lasers of Red (R), Green (G) and Blue (B) can be specifically used in the laser group. The light beams emitted by the lasers in the laser group 110 are combined into a laser beam by the beam combining unit 160 and coupled into the transmission fiber 130.
The processor 100 can also control the scan driving circuit 150 to drive the fiber scanner in the fiber scanning module 120 to scan and output the light beam transmitted in the transmission fiber 130.
The light beam scanned and output by the optical fiber scanner acts on a certain pixel point position on the surface of the medium, and forms a light spot on the pixel point position, so that the pixel point position is scanned. Under the driving of the optical fiber scanner, the output end of the transmission optical fiber 130 sweeps according to a certain scanning track, so that the light beam moves to the corresponding pixel point position. During actual scanning, the light beam output by the transmission fiber 130 will form a light spot with corresponding image information (e.g., color, gray scale or brightness) at each pixel location. In a frame time, the light beam traverses each pixel position at a high enough speed to complete the scanning of a frame of image, and because the human eye observes the object and has the characteristic of 'visual residual', the human eye cannot perceive the movement of the light beam at each pixel position but sees a frame of complete image.
With continued reference to fig. 1b, a specific structure of the fiber scanning module 120 is shown, which includes: scanning actuator 121, fiber suspension 122, mirror group 123, scanner package 124 and fixing member 125. The scanning actuator 121 is fixed in the scanner packaging case 124 through a fixing member 125, and the transmission fiber 130 extends at the front end of the scanning actuator 121 to form a fiber suspension 122 (also called a scanning fiber), so that, in operation, the scanning actuator 121 is driven by a scanning driving signal, the slow axis 121a (also called as the first actuating portion) vibrates along the vertical direction (the vertical direction is parallel to the Y axis in the reference coordinate system in fig. 1a and 1b, and in this application, the vertical direction may also be called as the first direction), the fast axis 121b (also called as the second actuating portion) vibrates along the horizontal direction (the horizontal direction is parallel to the X axis in the reference coordinate system in fig. 1a and 1b, and in this application, the horizontal direction may also be called as the second direction), and is driven by the scanning actuator 121, the front end of the fiber cantilever 122 performs two-dimensional scanning according to a predetermined track and emits a light beam, and the emitted light beam can realize scanning imaging through the lens assembly 123. In general, the structure formed by the scan actuator 121 and the fiber suspension 122 can be referred to as: an optical fiber scanner.
As shown in fig. 2, in the embodiment of the present application, the movement locus of the light exit end of the optical fiber forms a scanning curved surface 230 through the movement of the fast and slow axes, and is converted into an imaging plane 240 after passing through the corresponding mirror group 123. When applied in a near-eye display device such as an Augmented Reality (AR) device, the imaging plane 240 couples the entrance pupil as a waveguide into the waveguide for imaging for viewing by the human eye.
For convenience of description and to make those skilled in the art easily understand the solution of the present application, it should be noted that the optical imaging lens assembly (such as the lens assembly 123 shown in fig. 2) in the present application is used as an eyepiece, and under the action of the optical imaging lens assembly, the scanning curved surface 230 can be converted into an imaging plane 240 (in practical application, the transmission direction of light is from the scanning curved surface 230 to the imaging plane 240), so that one side of the optical imaging lens assembly corresponding to the imaging plane 240 is referred to as a first side, and one side of the optical imaging lens assembly corresponding to the scanning curved surface 230 is referred to as a second side. In the following, embodiments of the optical imaging lens group will be described with reference to "the first side" and "the second side". Also, 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 X-th lens" refers to a surface of the X-th lens facing the first side.
It should be further noted that, in the field of projection, the image corresponding to the first side is a planar image, the corresponding planar image carrier may be a projection screen, a curtain, or a wall surface, etc., and the image corresponding to the second side is a curved image, i.e., an arc-shaped scanning surface scanned by the optical fiber scanner or emitted by another image source; in a use scene of the camera shooting field, the light path is opposite to that in the projection field, the first side generally corresponds to an object side surface for collecting image information, and the second side generally corresponds to an image side surface for collecting imaging.
Optical imaging lens group
The optical imaging lens group in the embodiment of the application comprises: the lens comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens which are arranged from a first side to a second side in a coaxial way in sequence, and the total number of the lenses is six. It should be noted that, in the embodiment of the present application, the focal lengths of the first lens element to the sixth lens element are positive, negative, positive, and negative, respectively. By simultaneously carrying out positive and negative reasonable optimization setting on the focal lengths of the six lenses with the same optical axis, the focal power of the system can be reasonably dispersed, the aberration generated by the lenses is reduced, and the aim of correcting various aberrations is fulfilled, so that clear imaging of the curved surface of the image space is realized on the basis of improving the field angle. In addition, it should be emphasized that the focal length of the sixth lens element is set to be negative, which is beneficial for receiving light rays with a large viewing angle, so that information from the curved image can be more fully captured; by setting the focal length of the first lens to be positive, the convergence power of the final planar image can be enhanced to balance the aberrations.
Further specifically, it is preferable that the various lenses satisfy the following relational expressions: 1<f1/f<2、6<f2/f<30、0.2<|f3/f|<1、1<f4/f<3、0.5<f5/f<1.5 and 1<|f6/f|<2.5; wherein f is1Is the focal length of the first lens, f2Is the focal length of the second lens, f3Is the focal length of the third lens, f4Is the focal length of the fourth lens, f5Is the focal length of the fifth lens, f6F is the focal length of the sixth lens element, and f is the focal length of the optical imaging lens assembly (which can also be understood as the equivalent focal length of the optical imaging lens assembly). It should be noted that, by more specifically defining the focal length of each lens, the focal powers of the system are more reasonably dispersed and configured, so as to further enhance the correction of various aberrations, and improve the field angle and the imaging quality. In addition, if the position of the area where the focal length of the lens is located 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 paraxial region. Before the applicant of the present invention, it is emphasized that the existing optical imaging lens group for projection display cannot achieve the balance between the imaging quality and the large field angle, that is, the imaging quality is generally reduced when the field angle is increased, and the imaging quality cannot be ensured and the large field angle cannot be achieved. According to the invention and creation scheme, the combination control of the focal lengths and the surface structures of the six lenses is adopted, so that the field angle is improved, and the high-quality output of imaging is achieved.
Further, in a possible embodiment, the connection mode between the six lenses can be interval connection, and can also be bonded together by adhesion, which will be determined according to the needs of the practical application, and is not limited herein.
Further, in one possible embodiment, the various lenses described above also satisfy the following relationships:
1.5< n1<1.7, 1.5< n2<1.7, 1.6< n3<1.7, 1.5< n4<1.6, 1.45< n5<1.6, 1.5< n6< 1.7; where n1 is a refractive index of the first lens, n2 is a refractive index of the second lens, n3 is a refractive index of the third lens, n4 is a refractive index of the fourth lens, n5 is a refractive index of the fifth lens, and n6 is a refractive index of the sixth lens. Preferably, n1 is 1.59, n2 is 1.53 or 1.64, n3 is 1.67, n4 is 1.52, n5 is 1.53, and n6 is 1.53. It should be noted that, by limiting the refractive index of the six lenses through an optimized design, the dispersion coefficient of the corresponding lens can be reasonably controlled, so as to ensure the imaging quality and the large field angle.
Further optionally, in order to better ensure the imaging quality, the embodiments of the present invention further specifically and preferably limit the abbe number of the six lenses, specifically defined as: the abbe number of the first lens is 29.9, the abbe number of the second lens is 56.1 or 22.4, the abbe number of the third lens is 19.3, the abbe number of the fourth lens is 52.1, the abbe number of the fifth lens is 55.0, and the abbe number of the sixth lens is 56.1. It should be noted that, in other embodiments of the present invention, the abbe numbers of the six lenses defined in the embodiments of the present invention are not limited, and other abbe numbers capable of ensuring that the six lenses have good matching relationship may also be used, so as to ensure the final imaging quality.
Further optionally, in one possible embodiment, the first side surface of the third lens is concave at a paraxial region and the second side surface of the third lens is convex; the first side surface of the fourth lens is a convex surface, and the second side surface of the fourth lens is a concave surface; the first side surface and the second side surface of the fifth lens are convex surfaces; the first side surface of the sixth lens element is convex and the second side surface of the sixth lens element is concave at paraxial region. By limiting the surface type structure of the corresponding side surface of the lens, the aberration generated between the lenses can be further effectively corrected, the optical sensitivity is reduced, and the final imaging quality and the field angle are improved. In addition, the first side surface is a convex surface, which means that the first side surface is convex toward the first side direction of the optical imaging lens group; the first side surface is a concave surface, which means that the first side surface forms a concave shape towards the first side direction of the optical imaging lens group; the second side surface is a convex surface, which means that the second side surface forms a convex shape towards the second side direction of the optical imaging lens group; the second side surface is a concave surface, which means that the second side surface forms a concave shape towards the second side direction of the optical imaging lens group. It should be emphasized that, in other embodiments of the present invention, the surface type structures of the third lens, the fourth lens, the fifth lens and the sixth lens are not limited to be limited simultaneously as in this embodiment, and the surface type structure of at least one of the lenses may also be limited, such as the surface type structure of the first side surface and the second side surface of the sixth lens, and the surface type structures of the other lenses are not limited.
Further, in some embodiments, the lens surface shape is not concave or convex over the entire side surface, and may be a compound curve, or a curve near the optical axis portion and a curve at the edge portion; particularly, alternatively, 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 position of the lens surface near the optical axis; similarly, when the lens surface is concave and the position of the concave is not defined, it means that the concave can be located at the position of the lens surface near the optical axis.
Further optionally, in a possible embodiment, the first side surface and the second side surface of the first lens to the sixth lens are both aspheric surface shaped structures. It should be noted that, by limiting the mirror structures of the first lens element to the sixth lens element to aspheric surface structures, more control variables can be obtained to reduce the aberration and reduce the number of lens elements reasonably, thereby facilitating the miniaturization of the optical imaging lens assembly on the basis of improving the image display quality. In addition, the first side surface and the second side surface of the lens are both aspheric surface shaped structures, and it can be understood that the whole or a part of the optical effective area of the lens surface is aspheric.
Further optionally, in one possible embodiment, the first to sixth lenses are all made of plastic. It should be noted that the first lens to the sixth lens made of plastic can effectively reduce the production cost, and compared with the glass material, the cost of the plastic lens is one twentieth to one tenth of the cost of the glass material, so that the low-cost batch production is very facilitated; in addition, the plastic lens can be generally formed by injection molding, has low processing difficulty and can be easily processed into various profile structures meeting the aspheric surface, and meanwhile, the plastic lens can also integrally reduce the weight of the lens, thereby being beneficial to the light product design.
In addition, it should be further noted that, optionally, at least one stop may be disposed before the first lens element (on the first side), between the lens elements, or after the last sixth lens element (on the second side), and the type of the stop may be, for example, an aperture stop or a field stop, which may be used to reduce stray light and help to improve image display quality.
Example one
Fig. 3 is a schematic structural diagram of an optical imaging lens assembly according to an embodiment of the present invention. 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 and a sixth lens 16 which are arranged in sequence from a first side (i.e. the side where the diaphragm 01 is located in fig. 3) to a second side (i.e. the side where the scanning curved surface 02 is located in fig. 3) in a coaxial manner.
In this embodiment, each two adjacent lenses of the first lens 11, the second lens 12, the third lens 13, the fourth lens 14, the fifth lens 15, and the sixth lens 16 have a space therebetween, and the first lens 11, the second lens 12, the third lens 13, the fourth lens 14, the fifth lens 15, and the sixth lens 16 are six single non-cemented lenses.
The focal lengths of the first lens 11 to the sixth lens 16 from the first side to the second side are positive, negative, positive, and negative in sequence.
The first side surface and the second side surface of the first lens 11 are convex.
The first side surface of the second lens 12 is concave and the second side surface is convex.
The first side surface of the third lens element 13 is concave at the paraxial region, and the second side surface is convex.
The first side surface of the fourth lens element 14 is convex and the second side surface is concave.
The first side surface and the second side surface of the fifth lens 15 are convex.
The sixth lens element 16 has a convex first side surface and a concave second side surface at a paraxial region.
In the present embodiment, the focal lengths of the first lens element 11 to the sixth lens element 16 in the optical imaging lens group satisfy the following relations:
1<f1/f<2、6<f2/f<30、0.2<|f3/f|<1、1<f4/f<3、0.5<f5/f<1.5 and 1<|f6/f|<2.5; wherein f is1Is the focal length of the first lens 11, f2Is the focal length of the second lens 12, f3Is the focal length of the third lens 13, f4Is the focal length of the fourth lens 14, f5Is the focal length of the fifth lens 15, f6Is the focal length of the sixth lens element 16, and f is the equivalent focal length of the optical imaging lens assembly.
The refractive index and the dispersion coefficient of the first lens 11 to the sixth lens 16 in the optical imaging lens group respectively satisfy the following conditions:
n1 is 1.59, n2 is 1.53, n3 is 1.67, n4 is 1.52, n5 is 1.53, n6 is 1.53. Wherein n1 to n6 represent refractive indices of the first lens 11 to the sixth lens 16, respectively; the abbe number of the first lens is 29.9, the abbe number of the second lens is 56.1, the abbe number of the third lens is 19.3, the abbe number of the fourth lens is 52.1, the abbe number of the fifth lens is 55.0, and the abbe number of the sixth lens is 56.1.
In the optical imaging lens group provided by the first embodiment of the invention, the material of the lens is plastic; the equivalent focal length of the whole optical imaging lens group is 3.00mm, the aperture value is 1.37, the half field angle is 13 degrees, and the preferable parameters of the curvature radius, the thickness parameter, the refractive index and the dispersion coefficient of each lens for imaging the scanning curved surface 02 are shown in table 1:
TABLE 1 structural parameters of the optical imaging lens assembly in the first embodiment
Surface of Lens serial number Surface shape Radius of curvature Thickness/spacing Material Refractive index of material Coefficient of dispersion
0 Imaging plane Plane surface Infinite number of elements Infinite number of elements
1 Diaphragm 01 Infinite number of elements 1
2 First lens 11 Aspherical surface 8.985 1.792 Plastic material 1.59 29.9
3 Aspherical surface -3.161 0.141
4 Second lens 12 Aspherical surface -7.705 0.692 Plastic material 1.53 56.1
5 Aspherical surface -4.914 1.098
6 Third lens 13 Aspherical surface -0.587 1.412 Plastic material 1.67 19.3
7 Aspherical surface -12.742 0.100
8 Fourth lens 14 Aspherical surface 1.869 1.062 Plastic material 1.52 52.1
9 Aspherical surface 6.861 1.037
10 Fifth lens 15 Aspherical surface 2.206 2.238 Plastic material 1.53 55.0
11 Aspherical surface -2.196 0.100
12 Sixth lens 16 Aspherical surface 1.822 1.616 Plastic material 1.53 56.1
13 Aspherical surface 0.749 0.652
14 Scanning curved surface 02 Spherical surface 2
It should be noted that table 1 is detailed structural data of the optical imaging lens assembly of the first embodiment, wherein the units of the radius of curvature, the thickness and the focal length are all millimeters, and surfaces 0-14 sequentially represent the surfaces from the first side to the second side; an optical surface in the imaging plane with a radius of curvature of "infinity" is referred to as a flat surface.
Further, aspherical conic coefficients of the corresponding surfaces of the first lens 11 to the sixth lens 16 are shown in table 2 below:
TABLE 2 aspherical Cone coefficient data for different lens surfaces in example one
Surface of 2 3 4 5 6 7
K -2.6707E+001 -1.7120E+000 1.1732E+001 -3.7860E+000 -1.7133E+000 8.0525E+000
Surface of 8 9 10 11 12 13
K -4.8692E+000 -9.9997E+001 -7.0885E+000 -3.2483E+000 -2.2496E-001 -1.5077E+000
Table 2 shows aspheric coefficient data in the first embodiment, where k is the cone coefficient in the aspheric curve equation.
Further, through tests, when the optical imaging lens group is adopted to project image light corresponding to a scanning surface, an optical transfer function curve graph is shown in fig. 4, a field curvature distortion curve graph is shown in fig. 5, an axial chromatic aberration curve graph is shown in fig. 6, and a vertical chromatic aberration curve graph is shown in fig. 7; wherein, the Modulation Transfer Function (MTF) represents the comprehensive resolution level of an optical system, the field distortion curve represents the F-tan (theta) distortion value (percentage) under different field angles, and the axial chromatic aberration curve and the vertical chromatic aberration curve represent chromatic aberration in different directions.
As can be seen from fig. 4-7, the optical imaging lens assembly of the first embodiment has good imaging resolution and small distortion and chromatic aberration of the optical system in the full field of view, so that the optical imaging lens assembly can clearly image the scanning curved image of the optical fiber scanner, and has good imaging effect.
Certainly, in practical applications, the optical imaging lens assembly may further include a photosensitive element, a housing, and the like, the photosensitive element may be disposed at the second side of the optical imaging lens assembly, and the optical imaging lens assembly may be mounted in the housing, so that a curved image formed by scanning an image source (such as an optical fiber scanner) may be imaged on a plane, thereby realizing clear imaging.
Example two
Fig. 8 is a schematic structural diagram of an optical imaging lens assembly according to an embodiment of the present invention. The optical imaging lens group comprises a first lens 31, a second lens 32, a third lens 33, a fourth lens 34, a fifth lens 35 and a sixth lens 36 which are coaxially arranged in sequence from a first side (i.e. the side where the diaphragm 03 is located in fig. 8) to a second side (i.e. the side where the scanning curved surface 04 is located in fig. 8).
In the present embodiment, each two adjacent lenses of the first lens 31, the second lens 32, the third lens 33, the fourth lens 34, the fifth lens 35, and the sixth lens 36 have a space therebetween, and the first lens 31, the second lens 32, the third lens 33, the fourth lens 34, the fifth lens 35, and the sixth lens 36 are six single non-cemented lenses.
The focal lengths of the first lens 31 to the sixth lens 36 from the first side to the second side are positive, negative, positive, and negative in sequence.
The first lens 31 is a biconvex lens, i.e., its first and second side surfaces are convex.
The first side surface of the second lens 32 is concave and the second side surface is convex.
The first side surface of the third lens element 33 is concave at the paraxial region and the second side surface is convex.
The first side surface of the fourth lens 34 is convex and the second side surface is concave.
The first side surface and the second side surface of the fifth lens 35 are convex;
the sixth lens element 36 has a convex first side surface and a concave second side surface at a paraxial region.
In the present embodiment, the focal lengths of the first lens element 31 to the sixth lens element 36 in the optical imaging lens group satisfy the following relations:
1<f1/f<2、6<f2/f<30、0.2<|f3/f|<1、1<f4/f<3、0.5<f5/f<1.5 and 1<|f6/f|<2.5; wherein f is1Is the focal length of the first lens 31, f2Is the focal length of the second lens 32, f3Is the focal length of the third lens 33, f4Is the focal length of the fourth lens 34, f5Is the focal length of the fifth lens 35, f6Is the focal length of the sixth lens element 36, and f is the equivalent focal length of the optical imaging lens assembly.
The refractive index and the dispersion coefficient of the first lens 31 to the sixth lens 36 in the optical imaging lens group respectively satisfy the following conditions:
n1 is 1.59, n2 is 1.64, n3 is 1.67, n4 is 1.52, n5 is 1.53, n6 is 1.53. Wherein n 1-n 6 represent refractive indexes of the first lens 31-the sixth lens 36, respectively; the abbe number of the first lens is 29.9, the abbe number of the second lens is 22.4, the abbe number of the third lens is 19.3, the abbe number of the fourth lens is 52.1, the abbe number of the fifth lens is 55.0, and the abbe number of the sixth lens is 56.1.
In the optical imaging lens group provided by the second embodiment of the invention, the material of the lens is plastic; the equivalent focal length of the whole optical imaging lens group is 3.00mm, the aperture value is 1.37, the half field angle is 13 degrees, and the preferable parameters of the curvature radius, the thickness parameter, the refractive index and the dispersion coefficient of each lens for imaging the scanning curved surface 04 are shown in table 3:
TABLE 3 structural parameters of the optical imaging lens assembly of the second embodiment
Figure BDA0003148233420000131
Figure BDA0003148233420000141
It should be noted that table 3 is detailed structural data of the optical imaging lens assembly of the second embodiment, wherein the units of the radius of curvature, the thickness and the focal length are all millimeters, and the surfaces 0-14 sequentially represent the surfaces from the first side to the second side; an optical surface in the imaging plane with a radius of curvature of "infinity" is referred to as a flat surface.
Further, tests show that when the optical imaging lens group is used to project image light corresponding to a scanning surface, an optical transfer function curve graph is shown in fig. 9, a field curvature distortion curve graph is shown in fig. 10, an axial chromatic aberration curve graph is shown in fig. 11, and a vertical chromatic aberration curve graph is shown in fig. 12; wherein, the Modulation Transfer Function (MTF) represents the comprehensive resolution level of an optical system, the field distortion curve represents the F-tan (theta) distortion value (percentage) under different field angles, and the axial chromatic aberration curve and the vertical chromatic aberration curve represent chromatic aberration in different directions.
As can be seen from fig. 9-12, the optical imaging lens assembly of the second embodiment has good imaging resolution and small distortion and chromatic aberration of the optical system in the full field of view, so that the optical imaging lens assembly can clearly image the scanning curved image of the optical fiber scanner, and has good imaging effect.
Certainly, in practical applications, the optical imaging lens assembly may further include a photosensitive element, a housing, and the like, the photosensitive element may be disposed at the second side of the optical imaging lens assembly, and the optical imaging lens assembly may be mounted in the housing, so that a curved image formed by scanning an image source (such as an optical fiber scanner) may be imaged on a plane, thereby realizing clear imaging.
Scanning display device
The optical imaging lens group can cooperate with an optical fiber scanner (or a corresponding optical fiber scanning module) to form a scanning display device in the embodiment of the present application (as shown in fig. 1a and 1b, the optical imaging lens group is disposed on a light emitting path of the optical fiber scanner), wherein a first side of the optical imaging lens group faces a light emitting direction of the optical fiber scanner, and a preferred mode is that the optical imaging lens group is coaxial with a central optical axis of the optical fiber scanner. Of course, reference may be made to the corresponding contents in fig. 1a and 1b for the structure and the general principle of the fiber scanner, and redundant description is omitted here.
Near-to-eye display device
In the present application, the scanning display device can be further applied to a near-eye display device, and can be used as a head-mounted AR device (e.g., AR glasses) in cooperation with a near-eye display module to form the near-eye display device in the embodiment of the present application. The scanning display device is arranged in the near-eye display module.
Wherein, can include among the near-to-eye display module assembly: light source, processing control circuit, wearable frame structure, waveguide, etc. The image light beam output by the light source enters the scanning display device, and is scanned and output to the optical display mirror group by the optical fiber scanner therein, the scanning curved surface (refer to the scanning curved surface 02 in fig. 3 and the scanning curved surface 230 in fig. 2) of the optical fiber scanner passes through the optical display mirror group and is converted into an imaging plane (refer to the imaging plane 240 in fig. 2), and the imaging plane is coupled into the waveguide as the entrance pupil surface of the waveguide, and is then coupled out through waveguide expansion imaging and enters human eyes.
As another possible implementation manner, the scanning display device may further cooperate with the near-eye display module to form a near-eye display device in the embodiment of the present application, and serve as a head-mounted VR device (e.g., VR headset/glasses). The scanning display device is arranged in the near-eye display module.
In the embodiment of the application, the focal lengths of six lenses with the same optical axis of the optical imaging lens group are reasonably and optimally set, so that the focal power of the system can be reasonably dispersed, the aberration generated by the lenses is reduced, the aim of correcting various aberrations is fulfilled, and clear imaging of an image side curved surface is realized on the basis of improving the field angle; the refractive index, the dispersion coefficient and the surface type structure of the six lenses with the same optical axis are limited and optimized, so that the imaging quality and the field angle are further improved; the six coaxial lenses are limited and optimally designed to be aspheric surface-shaped structures and made of plastic materials, so that the imaging quality is further improved, the forming processing difficulty of the whole optical imaging lens group is reduced, and the mass production is favorably realized at low cost.
The above embodiments are merely preferred embodiments of the present application, and the embodiments are only used for illustrating the technical solutions of the present application and not for limiting the present application, and all technical solutions that can be obtained by a person skilled in the art through logic analysis, reasoning or effective experiments according to the concepts of the present application should be within the scope of the present application.
The embodiments in the present application are described in a progressive manner, and the same and similar parts among the embodiments can be referred to each other, and each embodiment focuses on the differences from the other embodiments.
The expressions "first", "second", "said first" or "said second" used in various embodiments of the present disclosure may modify various components regardless of order and/or importance, but these expressions do not limit the respective components. The above description is only configured for the purpose of distinguishing elements from other elements. For example, the first lens and the second lens represent different lenses, although both are lenses.

Claims (10)

1. The utility model provides an optical imaging lens group which characterized in that, optical imaging lens group includes first lens, second lens, third lens, fourth lens, fifth lens and the sixth lens that is arranged by first side to second side sharing optical axis in proper order, first lens to the focus that the sixth lens corresponds is positive, negative, positive and negative respectively.
2. The optical imaging lens group of claim 1 wherein each of said lenses satisfies the following relationship: 1<f1/f<2、6<f2/f<30、0.2<|f3/f|<1、1<f4/f<3、0.5<f5/f<1.5 and 1<|f6/f|<2.5;
Wherein f is1Is the focal length of the first lens, f2Is the focal length of the second lens, f3Is the focal length of the third lens, f4Is the focal length of the fourth lens, f5Is the focal length of the fifth lens, f6F is the focal length of the sixth lens element, and f is the focal length of the optical imaging lens group.
3. The optical imaging lens assembly of claim 2 wherein each of said lenses further satisfies the relationship:
1.5<n1<1.7,1.5<n2<1.7,1.6<n3<1.7,1.5<n4<1.6,1.45<n5<1.6,1.5<n6<1.7;
wherein n1 is a refractive index of the first lens, n2 is a refractive index of the second lens, n3 is a refractive index of the third lens, n4 is a refractive index of the fourth lens, n5 is a refractive index of the fifth lens, and n6 is a refractive index of the sixth lens.
4. The optical imaging lens group of claim 3, wherein n1 is 1.59, n2 is 1.53 or 1.64, n3 is 1.67, n4 is 1.52, n5 is 1.53, and n6 is 1.53;
the abbe number of each of the lenses satisfies: the abbe number of the first lens is 29.9, the abbe number of the second lens is 56.1 or 22.4, the abbe number of the third lens is 19.3, the abbe number of the fourth lens is 52.1, the abbe number of the fifth lens is 55.0, and the abbe number of the sixth lens is 56.1.
5. The optical imaging lens assembly of any one of claims 1-4, wherein the first side surface of the sixth lens element is convex and the second side surface of the sixth lens element is concave at paraxial region.
6. The optical imaging lens assembly of claim 5 wherein the first side surface of the third lens element is concave at paraxial region and the second side surface of the third lens element is convex; the first side surface of the fourth lens is a convex surface, and the second side surface of the fourth lens is a concave surface; the first side surface and the second side surface of the fifth lens are convex surfaces.
7. The optical imaging lens group of claim 1, wherein the first side surface and the second side surface of the first lens element to the sixth lens element are aspheric surface structures;
the first lens to the sixth lens are all made of plastic;
the second side of the optical imaging lens group corresponds to a curved image, and the first side of the optical imaging lens group corresponds to a planar image.
8. A scanning display device, comprising an optical fiber scanner and the optical imaging lens group of any one of the preceding claims 1 to 7, wherein 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, imaging and projecting a scanning surface corresponding to the light emitted by the optical fiber scanner;
the optical fiber scanner comprises an actuator and an optical fiber fixed on the actuator, wherein a part of the optical fiber, which exceeds the actuator, forms an optical fiber cantilever, and the optical fiber cantilever is driven by the actuator to perform two-dimensional scanning.
9. A near-eye display apparatus, wherein the near-eye display apparatus is used as a head-mounted augmented reality apparatus, and comprises at least a near-eye display module and the scanning display device according to claim 8, and the scanning display device is disposed in the near-eye display module.
10. A near-eye display apparatus, wherein the near-eye display apparatus is used as a head-mounted virtual reality apparatus, and comprises at least a near-eye display module and the scanning display device according to claim 8, and the scanning display device is disposed in the near-eye display module.
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Publication number Priority date Publication date Assignee Title
KR20140019663A (en) * 2012-08-07 2014-02-17 주식회사 세코닉스 F-theta wide angle lens system for rear view camera of vehicle
CN112904530A (en) * 2020-12-21 2021-06-04 成都理想境界科技有限公司 Optical imaging lens group, scanning display device and near-to-eye display equipment
JP2021089348A (en) * 2019-12-03 2021-06-10 カンタツ株式会社 Imaging lens

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20140019663A (en) * 2012-08-07 2014-02-17 주식회사 세코닉스 F-theta wide angle lens system for rear view camera of vehicle
JP2021089348A (en) * 2019-12-03 2021-06-10 カンタツ株式会社 Imaging lens
CN112904530A (en) * 2020-12-21 2021-06-04 成都理想境界科技有限公司 Optical imaging lens group, scanning display device and near-to-eye display equipment

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