WO2022078023A1 - 镜头、投影光机以及近眼显示系统 - Google Patents

镜头、投影光机以及近眼显示系统 Download PDF

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Publication number
WO2022078023A1
WO2022078023A1 PCT/CN2021/110306 CN2021110306W WO2022078023A1 WO 2022078023 A1 WO2022078023 A1 WO 2022078023A1 CN 2021110306 W CN2021110306 W CN 2021110306W WO 2022078023 A1 WO2022078023 A1 WO 2022078023A1
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WIPO (PCT)
Prior art keywords
lens
light
sub
transmitted light
display
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Application number
PCT/CN2021/110306
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English (en)
French (fr)
Inventor
郑光
Original Assignee
Oppo广东移动通信有限公司
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Publication date
Priority claimed from CN202022286796.5U external-priority patent/CN212781467U/zh
Priority claimed from CN202011097931.XA external-priority patent/CN112162383A/zh
Application filed by Oppo广东移动通信有限公司 filed Critical Oppo广东移动通信有限公司
Publication of WO2022078023A1 publication Critical patent/WO2022078023A1/zh

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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B13/00—Optical objectives specially designed for the purposes specified below
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/01—Head-up displays
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS 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
    • G03B21/00—Projectors or projection-type viewers; Accessories therefor
    • G03B21/14—Details

Definitions

  • the present application relates to the technical field of display projection, and in particular, to a lens, a projector and a near-eye display system.
  • augmented reality devices such as smart glasses or smart masks are widely accepted and applied by users.
  • the augmented reality device can usually include a projector and a camera.
  • the projector can generate a virtual image, and the light of the virtual image and the light of the real environment can be injected into the pupil of the user wearing the augmented reality device at the same time, so that the user wearing the augmented reality device can not only see To real things, you can also see virtual images.
  • Embodiments of the present application provide a lens, an optical projector, and a near-eye display system.
  • the lens can be applied to an optical projector to modulate an effective optical signal emitted by the optical projector.
  • An embodiment of the present application provides a lens, which includes a first lens, a second lens, a third lens and a fourth lens arranged in sequence along an optical axis direction, and the first lens is used for condensing effective optical signals emitted by a display to form a first transmitted light signal, the second lens is used to disperse the first transmitted light signal to form a second transmitted light signal, and the third lens is used to disperse the second transmitted light signal to form a third the transmitted light signal, and the fourth lens is used for condensing the third transmitted light signal to form a fourth transmitted light signal.
  • An embodiment of the present application provides an optical projector, including a display and a lens, the lens is the lens described in the above embodiments of the application, the display is used for emitting effective light signals, and the display is arranged on one side of the lens and adjacent to the first lens so that the effective optical signal can be incident on the first lens.
  • Embodiments of the present application provide a near-eye display system, including:
  • the pixels of the display emit effective light signals with different emission angles, and the effective light signals include image information
  • a lens arranged on one side of the display, for receiving the effective optical signal and modulating the effective optical signal, so that the effective optical signal generated by one of the pixel points forms different exit angles after passing through the lens the parallel beam;
  • a waveguide element is arranged on the side of the lens away from the display, and the waveguide element is used for receiving the parallel light beam and converting the parallel light beam into a virtual image.
  • FIG. 1 is a first structural diagram of the light projector provided by the embodiment of the present application.
  • FIG. 2 is a diagram of a modulation transfer function of a lens in the projector shown in FIG. 1 .
  • FIG. 3 is a field curvature diagram of a lens in the optical projector shown in FIG. 1 .
  • FIG. 4 is a distortion curve diagram of the lens in the optical projector shown in FIG. 1 .
  • FIG. 5 is a defocus curve diagram of the lens in the projector shown in FIG. 1 .
  • FIG. 6 is a schematic diagram of a second structure of the light projector provided by the embodiment of the present application.
  • FIG. 7 is a modulation transfer function diagram of the lens in the projector shown in FIG. 6 .
  • FIG. 8 is a field curvature diagram of the lens in the optical projector shown in FIG. 6 .
  • FIG. 9 is a distortion curve diagram of the lens in the optical projector shown in FIG. 6 .
  • FIG. 10 is a defocus curve diagram of the lens in the projector shown in FIG. 6 .
  • FIG. 11 is a schematic structural diagram of a near-eye display system provided by an embodiment of the present application.
  • An embodiment of the present application provides a lens, which includes a first lens, a second lens, a third lens and a fourth lens arranged in sequence along an optical axis direction, and the first lens is used for condensing effective optical signals emitted by a display to form a first transmitted light signal, the second lens is used to disperse the first transmitted light signal to form a second transmitted light signal, and the third lens is used to disperse the second transmitted light signal to form a third the transmitted light signal, and the fourth lens is used for condensing the third transmitted light signal to form a fourth transmitted light signal.
  • the first lens is a positive refractive power lens
  • the second lens is a negative refractive power lens
  • the third lens is a cemented lens
  • the combined light of the cemented lens The power is negative
  • the fourth lens is a positive power lens
  • the third lens includes a first sub-lens and a second sub-lens cemented with each other, and the first sub-lens is located between the second sub-lens and the second lens
  • the first sub-lens is a negative refractive power lens
  • the second sub-lens is located between the first sub-lens and the fourth lens
  • the second sub-lens is a positive refractive power lens.
  • the first sub-lens includes an incident surface and a first cementing surface disposed opposite to each other, the incident surface faces the third lens and the incident surface is a concave surface, and the incident surface is a concave surface.
  • the glued surface is concave;
  • the second sub-lens includes a second gluing surface and an exit surface disposed opposite to each other, the second gluing surface is connected with the first gluing surface, the second gluing surface is a convex surface, and the second gluing surface is a convex surface.
  • the shape is adapted to the shape of the first cementing surface, the exit surface faces the fourth lens, and the exit surface is a convex surface;
  • the second optical signal is incident from the incident surface, passes through the first adhesive surface and the second adhesive surface in sequence, and exits from the exit surface to form the third optical signal.
  • the first lens includes a first light-incident surface and a first light-emitting surface disposed opposite to each other, the first light-emitting surface is disposed close to the second lens, and the first light-emitting surface is disposed close to the second lens. Both the light incident surface and the first light exit surface are convex;
  • the second lens includes a second light incident surface and a second light exit surface arranged opposite to each other, the second light incident surface is located between the first light exit surface and the second light exit surface, and the second light entrance surface is located between the first light exit surface and the second light exit surface.
  • the light surface is a concave surface, and the second light emitting surface is a convex surface;
  • the fourth lens includes a third light incident surface and a third light exit surface opposite to each other, the third light incident surface is located between the third lens and the third light exit surface, and the third light incident surface is located between the third lens and the third light exit surface.
  • the surface is one of a convex surface, a concave surface and a plane structure, and the third light emitting surface is a convex surface.
  • the lens satisfies: TTL ⁇ 14mm, where TTL is the total optical length of the lens.
  • the aperture of the exit pupil of the lens is 3.5mm-6mm, and the maximum optical aperture of the lens is 5.4mm-8mm.
  • the lens satisfies: tan(FOV/2)/TTL>0.021mm-1, 25° ⁇ FOV ⁇ 32°, where FOV is the angle of view in the diagonal direction of the lens .
  • the total optical length of the lens is less than 14mm, and the lens satisfies: 1.0mm ⁇ T1 ⁇ 2.4mm, 0.3mm ⁇ T2 ⁇ 1mm, 1.9mm ⁇ T3 ⁇ 3.2mm, 0.6mm ⁇ T4 ⁇ 1.4mm;
  • T1 is the thickness of the first lens
  • T2 is the thickness of the second lens
  • T3 is the thickness of the third lens
  • T4 is the thickness of the fourth lens
  • the distance between the first lens and the second lens is greater than 1.8 mm, and the distance between the third lens and the fourth lens is less than 0.8 mm.
  • the distance between the first lens and the second lens is less than 0.5 mm, and the distance between the third lens and the fourth lens is less than 0.8 mm.
  • the lens satisfies: 8.6mm ⁇ f ⁇ 10.4mm, 4.2mm ⁇ f1 ⁇ 7.8mm, and 0.48 ⁇ f1/f ⁇ 0.88; -28mm ⁇ f2 ⁇ -14mm, and -3.3 ⁇ f2/f ⁇ -1.7;-28mm ⁇ f3 ⁇ -12mm, and -3.2 ⁇ f3/f ⁇ -1.4; 3.6mm ⁇ f4 ⁇ 6.4mm, and 0.32 ⁇ f4/f ⁇ 0.72;
  • f is the focal length of the lens
  • f1 is the focal length of the first lens
  • f2 is the focal length of the second lens
  • f3 is the focal length of the third lens
  • f4 is the focal length of the fourth lens.
  • the first lens, the second lens, the third lens and the fourth lens are all made of glass material.
  • An embodiment of the present application further provides an optical projector, including a display and a lens, the lens is the lens as described above, the display is used to emit an effective light signal, the display is arranged on one side of the lens and is connected to the lens. The first lenses are adjacent so that the effective optical signal can be incident on the first lenses.
  • the optical projector further includes a diaphragm, the diaphragm is disposed on a side of the fourth lens away from the third lens, and the diaphragm is coaxial with the lens It is arranged that the distance between the diaphragm and the lens is greater than 0.6 mm and less than 5 mm, and the diaphragm is used to modulate the fourth transmitted light signal so that the transmitted light signals passing through the diaphragm are mutually parallel.
  • the diaphragm includes a blocking area and a light-transmitting area
  • the blocking area is arranged around the periphery of the light-transmitting area
  • the light-transmitting area is a circular structure
  • the The light-transmitting area satisfies: 3.5mm ⁇ D ⁇ 6mm, where D is the aperture of the light-transmitting area.
  • Embodiments of the present application also provide a near-eye display system, including:
  • the pixels of the display emit effective light signals with different emission angles, and the effective light signals include image information
  • a lens arranged on one side of the display, for receiving the effective optical signal and modulating the effective optical signal, so that the effective optical signal generated by one of the pixel points forms different exit angles after passing through the lens the parallel beam;
  • a waveguide element is arranged on the side of the lens away from the display, and the waveguide element is used for receiving the parallel light beam and converting the parallel light beam into a virtual image.
  • the lens includes a first lens, a second lens, a third lens and a fourth lens arranged in sequence along the optical axis direction, and the first lens is disposed adjacent to the display so that the effective light signal generated by each pixel point can enter the first lens, and the first lens is used for converging the effective light signal generated by each pixel point to form a plurality of different exit angles the first transmitted light signals, the second lens is used for condensing the plurality of first transmitted light signals to form a plurality of second transmitted light signals with different exit angles, the third lens is used for dispersing the plurality of second transmitted light signals The second transmitted light signal is used to form a plurality of third transmitted light signals with different exit angles, and the fourth lens is used to disperse the third transmitted light signal to form a plurality of fourth transmitted light signals with different exit angles.
  • the plurality of fourth transmitted light signals corresponding to the pixel points are parallel to each other.
  • the total optical length of the lens is less than 14mm, and the lens satisfies: 1.0mm ⁇ T1 ⁇ 2.4mm, 0.3mm ⁇ T2 ⁇ 1mm, 1.9mm ⁇ T3 ⁇ 3.2mm, 0.6mm ⁇ T4 ⁇ 1.4mm;
  • T1 is the thickness of the first lens
  • T2 is the thickness of the second lens
  • T3 is the thickness of the third lens
  • T4 is the thickness of the fourth lens
  • the distance between the display and the first lens is less than 4 mm
  • the distance between the first lens and the second lens is greater than 1.8 mm
  • the third lens and the The distance between the fourth lenses is less than 0.8mm.
  • Embodiments of the present application provide a light projector, which is used to generate a virtual image.
  • FIG. 1 is a first structural diagram of the light projector provided by the embodiment of the present application.
  • the light projector 200 can project a virtual image.
  • the light projector 200 includes a display 220 and a lens 240, the lens 240 is arranged on one side of the display 220, and the display 220 can emit light, wherein the light signal for generating a virtual image is an effective light signal, and the effective light signal can be transmitted through the lens 240, and the lens 240
  • the effective optical signal can be corrected to eliminate various aberrations, so as to improve the imaging quality of the virtual image to be projected by the optical projector 200 .
  • the lens 240 may include a first lens 241 , a second lens 242 , a third lens 243 and a fourth lens 244 arranged in sequence along the optical axis direction (or the transmission direction of the effective optical signal), and the first lens 241 is adjacent to the display 220 set up. It can be understood that the first lens 241 , the second lens 242 , the third lens 243 and the fourth lens 244 are sequentially arranged from the image source side to the imaging side.
  • the first lens 241 can receive the effective optical signal emitted by the display 220 and condense the effective optical signal to form the first transmitted optical signal
  • the second lens 242 can receive and disperse the first transmitted optical signal to form the first transmitted optical signal.
  • the second transmitted light signal, the third lens 243 may receive and disperse the second transmitted light signal to form the third transmitted light signal
  • the fourth lens 244 may receive and condense the third transmitted light signal to form the fourth transmitted light signal.
  • the first lens 241 is a positive refractive power lens, which has a converging effect on the effective optical signal, and the effective optical signal can form the first transmitted light signal after passing through the first lens 241;
  • the second lens 242 is a negative refractive power lens, which is effective for The optical signal has a diverging effect, and the first transmitted optical signal can form a second transmitted optical signal after passing through the second lens 242;
  • the third lens 243 is a cemented lens and the combined refractive power of the cemented lens is negative.
  • the three transmitted light signals have a dispersing effect, and the second transmitted light signal can form a third transmitted light signal after passing through the third lens 243, which can reduce or correct chromatic aberration;
  • the fourth lens is a positive power lens, which has a convergence effect on the effective light signal , the fourth transmitted light signal can be formed after the third transmitted light signal passes through the fourth lens 244 .
  • the effective light signal emitted by the microdisplay of the embodiment of the present application may pass through the first lens 241 , the second lens 242 , the third lens 243 and the fourth lens 244 in sequence, and the four lenses may modulate the effective light signal to reduce the image poor, thereby improving the imaging effect of the virtual image projected by the light projector 200 .
  • the third lens 243 may be formed by gluing two single-piece lenses.
  • the third lens 243 may include a first sub-lens 2431 and a second sub-lens 2432, and one surface of the first sub-lens 2431 is matched with one surface of the second sub-lens 2432, so that the first sub-lens 2431 One surface of the second sub-lens 2432 and one surface of the second sub-lens 2432 may be glued to each other.
  • the first sub-lens 2431 is located between the second sub-lens 2432 and the second lens 242.
  • the first sub-lens 2431 is a lens with negative refractive power and has a divergent effect on the second transmitted light signal.
  • the second sub-lens 2432 is located between the first sub-lens 2431 and the fourth lens 244 .
  • the second sub-lens 2432 is a positive refractive power lens and has a converging effect on the optical signal transmitted through the first sub-lens 2431 .
  • the display 220 in this embodiment of the present application may be a micro display.
  • the display 220 may be an organic light-emitting diode (Organic Light-Emitting Diode, OLED) display or a micro liquid crystal display (liquid crystal display, LCD).
  • OLED Organic Light-Emitting Diode
  • LCD liquid crystal display
  • the brightness of OLED is less than 5000nits, and the brightness of LCD is less than 15000nits.
  • the display 220 in the embodiment of the present application may also be a Micro Light Emitting Diode (Micro-LED) display, such as a green Micro-LED, or other monochromatic Micro-LED or a white multi-color Micro-LED. LED.
  • Micro-LED Micro Light Emitting Diode
  • Micro-LED Compared with Micro-OLED and LCD, the brightness of Micro-LED can reach 2,000,000 nits, which is much higher than that of Micro-OLED and LCD. In addition, since Micro-LED is a self-illuminating light source, the projection system equipped with Micro-LED has better contrast ratio and better display delay.
  • the diagonal size of the effective light-emitting area of the display 220 is 0.17 inch-0.19 inch, and the aspect ratio of the effective light-emitting area is 1:1. In some other embodiments, the diagonal dimension of the effective light-emitting area of the display 220 is 0.25 inches-0.29 inches, and the aspect ratio of the effective light-emitting area is 16:9.
  • a glass cover plate is provided outside the effective light-emitting surface of the display 220 , and the glass cover plate may exist in an independent form or in the form of being integrated and packaged in the display 220 .
  • the thickness of the glass cover plate ranges from 0.3mm to 0.8mm.
  • the display 220 generates heat during operation, and the heat generated by the display 220 is conducted to the lens 240 .
  • the four lenses in the embodiment of the present application are all made of glass material. Compared with the lens made of plastic material, the thermal stability of the lens made of glass material is better, and the heat is not easy to generate deformation.
  • the first lens 241 , the second lens 242 , the first sub-lens 2431 , the second sub-lens 2432 and the fourth lens 244 in the embodiments of the present application are all spherical lenses, and the glass spherical solution is used to design a small-sized optical system, which can ensure The stability of the optical system over a wide range of temperature changes, while achieving smaller fabrication and assembly costs.
  • the first lens 241 includes a first light incident surface S11 and a first light emitting surface S12 disposed opposite to each other, the first light emitting surface S12 is disposed close to the second lens 242 , and the first light incident surface S11 and the first light emitting surface S12
  • the surfaces S12 are all convex surfaces. It can be understood that the first light incident surface S11 and the first light emitting surface S12 of the first lens 241 are both spherical structures, and the first light incident surface S11 is a surface that protrudes from the imaging side toward the image source side, and the first light emitting surface S11 is a convex surface.
  • the surface S12 is a surface that protrudes from the image source side toward the imaging side.
  • the second lens 242 includes a second light incident surface S21 and a second light exit surface S22 disposed opposite to each other, the second light incident surface S21 is located between the first light exit surface S12 and the second light exit surface S22, and the second light entrance surface S21 is The second light emitting surface S22 is a convex surface. It can be understood that the second light incident surface S21 and the second light exit surface S22 of the second lens 242 are both spherical structures, the second light incident surface S21 is a concave surface from the image source side toward the imaging side, and the second light exit surface S22 A surface that protrudes from the image source side toward the imaging side.
  • the third lens 243 includes a third light incident surface S31 and a third light exit surface S32 disposed opposite to each other, the third light incident surface S31 is located between the second light exit surface S22 and the third light exit surface S32, and the third light entrance surface S31 is
  • the third light-emitting surface S32 is a convex surface. It can be understood that the third light incident surface S31 and the third light emitting surface S32 of the third lens 243 are both spherical structures, the third light incident surface S31 is a concave surface from the image source side toward the imaging side, and the third light emitting surface S32 A surface that protrudes from the image source side toward the imaging side.
  • the first sub-lens 2431 includes a third light incident surface S31 and a first connection surface S33 that are opposite to each other, the first connection surface S33 is a concave surface, and the first connection surface S33 is formed concavely in the direction from the imaging side to the image source side .
  • the second sub-lens 2432 includes a second connecting surface S34 and a third light-emitting surface S32 disposed opposite to each other, the second connecting surface S34 is connected to the first connecting surface S33, the second connecting surface S34 is a convex surface, and the second connecting surface S34 is a It is formed to protrude from the image source side toward the imaging side. It should be noted that the size and shape of the first connection surface S33 and the second connection surface S34 are adapted to each other, and the first connection surface S33 and the second connection surface S34 shown in FIG. 1 overlap each other.
  • the structure of the third light emitting surface S32 is not limited to this.
  • the third light emitting surface S32 may also be a concave surface or a flat surface.
  • the fourth lens 244 includes a fourth light incident surface S41 and a fourth light exit surface S42 arranged opposite to each other, the fourth light entrance surface S41 is located between the third light exit surface S32 and the fourth light exit surface S42, and the fourth light entrance surface S41 can be It is one of a convex surface, a concave surface and a planar structure.
  • the fourth light incident surface S41 can be convex
  • the fourth light incident surface S41 is a structure formed by protruding from the imaging side toward the image source side.
  • the fourth light emitting surface S42 is a convex surface
  • the fourth light emitting surface S42 is a structure formed by protruding from the image source side toward the imaging side.
  • the fourth light-emitting surface S42 and the third light-emitting surface S32 are both spherical structures, and the distance between the spherical vertex of the fourth light-emitting surface S42 and the spherical vertex of the third light-emitting surface S32 is less than 0.8 mm, such as the fourth light-emitting surface S42.
  • the distance between the apex of the spherical surface and the apex of the spherical surface of the third light emitting surface S32 may be 0.8 mm, 0.5 mm, or 0.2 mm, or the like.
  • the first light incident surface S11 is a spherical structure, and the distance between the spherical vertex of the first light incident surface S11 and the display 220 is less than 4 mm.
  • the distance between the first light incident surface S11 and the display 220 may be 4mm, 3.5mm, 3mm, 2mm or 1mm etc. In some other embodiments, the distance between the spherical vertex of the first light incident surface S11 and the display 220 is less than 3 mm.
  • the first light-emitting surface S12 and the second light-incident surface S12 are both spherical structures, and the distance between the spherical vertex of the first light-emitting surface S12 and the spherical vertex of the second light-incident surface S12 is less than 1.8mm, such as 1.8mm, 1.5mm, 1mm or 0.5mm etc.
  • the projector 200 shown in FIG. 1 satisfies: 8.8mm ⁇ f ⁇ 10.6mm, 4.5mm ⁇ f1 ⁇ 7.3mm, and 0.46 ⁇ f1/f ⁇ 0.78; -11.9mm ⁇ f2 ⁇ -6.8mm, and -1.3 ⁇ f2/f ⁇ -0.7; -40mm ⁇ f3 ⁇ -18mm, and -3.6 ⁇ f3/f ⁇ -1.8; 8mm ⁇ f4 ⁇ 15mm, and 0.9 ⁇ f4/f ⁇ 1.4.
  • f is the focal length of the projector
  • f1 is the focal length of the first lens
  • f2 is the focal length of the second lens
  • f3 is the focal length of the third lens
  • f4 is the focal length of the fourth lens.
  • the third lens 243 satisfies: -2.1mm ⁇ f31 ⁇ -4.4mm, and -0.46 ⁇ f31/f ⁇ -0.24; 3.6mm ⁇ f32 ⁇ 7.1mm, and 0.35 ⁇ f32/f ⁇ 0.66.
  • f31 is the focal length of the first sub-lens
  • f32 is the focal length of the second sub-lens.
  • the optical projector 200 shown in FIG. 1 also satisfies: TTL ⁇ 14mm, where TTL (Total Track Length) is the total optical length of the optical projector.
  • TTL Total Track Length
  • the projector 200 that satisfies the above conditions can control the size of the projection lens as a whole, which is beneficial to realize the miniaturization of the projection lens 200 .
  • the total optical length of the projector can be 11.8mm
  • the lens size in the related art is 40mm ⁇ 18mm ⁇ 7mm.
  • the projector that satisfies the above conditions greatly reduces the size of the projector. Overall size.
  • the thickness T1 of the first lens 241 satisfies 1.0mm ⁇ T1 ⁇ 2.4mm, for example, the thickness of the first lens 241 may be 1.0mm, or 1.5mm, or 2.0mm, or 2.4mm, wherein the thickness of the first lens 241 refers to is the center thickness of the first lens 241.
  • the thickness T2 of the second lens 242 satisfies 0.3mm ⁇ T2 ⁇ 1mm, for example, the thickness of the second lens 242 may be 0.3mm, or 0.5mm, or 0.8mm, or 1mm, wherein the thickness of the second lens 242 refers to the second lens 242.
  • the center thickness of the lens 242 satisfies 0.3mm ⁇ T2 ⁇ 1mm, for example, the thickness of the second lens 242 may be 0.3mm, or 0.5mm, or 0.8mm, or 1mm, wherein the thickness of the second lens 242 refers to the second lens 242.
  • the center thickness of the lens 242 satisfies 0.3mm ⁇ T2 ⁇ 1mm
  • the thickness T3 of the third lens 243 satisfies 1.9mm ⁇ T3 ⁇ 3.2mm, for example, the thickness of the third lens 243 may be 1.9mm, or 2.5mm, or 3.0mm, or 3.2mm, wherein the thickness of the third lens 243 refers to The center thickness of the third lens 243 .
  • the thickness T31 of the first sub-lens 2431 satisfies 0.4mm ⁇ T31 ⁇ 0.8mm, for example, the thickness of the first sub-lens 2431 can be 0.4mm, 0.5mm or 0.8mm, and the thickness of the first sub-lens 2431 refers to the first sub-lens 2431.
  • the thickness refers to the center thickness of the second sub-lens 2432.
  • the thickness T4 of the fourth lens 244 satisfies 0.6mm ⁇ T4 ⁇ 1.4mm, for example, the thickness of the fourth lens 244 can be 0.6mm, or 1.0mm, or 1.4mm, wherein the thickness of the fourth lens 244 refers to the fourth lens 244 the center thickness.
  • the overall size of the projector 200 can be effectively controlled by reasonably setting the thicknesses between the lenses.
  • the optical projector 200 shown in FIG. 1 also satisfies: tan(FOV/2)/TTL>0.021mm-1, 25° ⁇ FOV ⁇ 32°, where FOV is the diagonal field of view of the optical projector 200 , f is the focal length of the projector 200 .
  • the light projector 200 that satisfies the above conditions can obtain a larger angle of view to meet the requirement of a large depth recognition range.
  • the aperture of the exit pupil of the projector 200 is 3.5mm-6mm, and the maximum optical aperture is 5.4mm-8mm.
  • the refractive index of the first lens 241 is between 1.75-1.88, and the Abbe number is between 38-54.
  • the refractive index of the second lens 242 is between 1.46-1.57, and the Abbe number is between 58-69.
  • the refractive index of the first sub-lens 2431 in the third lens 243 is between 1.88-1.98, the Abbe number is between 16-36, the refractive index of the second sub-lens 2432 in the third lens 243 is between 1.8-1.88, the Abbe number is between 1.8-1.88 Between 26-36.
  • the refractive index of the fourth lens 244 is between 1.88-1.98, and the Abbe number is between 16-36.
  • the FOV in the diagonal direction is 28, the ratio of the horizontal to vertical field of view is 1:1, the total optical length TTL of the lens 240 is 11.8mm, the focal length f of the lens 240 is 9.4mm, and the maximum optical diameter D is 6.8mm , the exit pupil diameter is 5mm.
  • the focal length f1 of the first lens 241 is 5.9 mm
  • the focal length f2 of the second lens 242 is -9.4 mm
  • the focal length f3 of the third lens 243 is -26 mm
  • the focal length f31 of the first sub-lens 2431 in the third lens 243 is -3.2 mm
  • the focal length f32 of the second sub-lens 2432 in the third lens 243 is 5.3 mm
  • the focal length f4 of the fourth lens 244 is 10.9 mm.
  • FIG. 2 is a diagram of the modulation transfer function of the lens in the optical projector shown in FIG. 1
  • FIG. 3 is a field curvature diagram of the lens in the optical projector shown in FIG. 1
  • FIG. 4 is shown in FIG. 1.
  • the distortion curve diagram of the lens in the light projector FIG. 5 is the defocus curve diagram of the lens in the light projector shown in FIG. 1 .
  • 2 , 3 , 4 and 5 all show relevant parameter graphs of the lens 240 having the parameters as shown in Table 1 .
  • Modulation Transfer Function refers to the relationship between the modulation degree and the number of line pairs per millimeter in the image, which can be used to evaluate the imaging quality of the lens, and can be reflected in the ability of the imaging to restore the details of the original object;
  • the field curvature diagram can represent the curvature and warpage of the imaging surface of the lens;
  • the distortion diagram can represent the degree of deformation of the imaging image of the lens;
  • the defocus curve can represent the depth of focus information of the lens. It can be seen from FIG. 2 to FIG.
  • the imaging quality of the embodiment of the present application is much higher than the Nyquist sampling evaluation of the system, and the distortion and field curvature are limited to a range far smaller than the range that cannot be detected by the human eye, and
  • the assembly and debugging sensitivity of the system is weaker than the accuracy commonly used in current production, which facilitates the mass production process.
  • the optical distortion amount of the lens 240 in the embodiment of the present application is controlled in the range of -1.0% to 1.0%, which illustrates the deformation of the imaging picture of the lens 240 in the embodiment of the present application.
  • the peaks of almost all the curves are near the vertical axis of zero offset, indicating that the defocus characteristics of the lens 240 are excellent, and a larger effective depth of focus value range can be obtained.
  • all the peaks of the defocus characteristic curves are in the higher value region, and the imaging contrast is excellent.
  • the light projector 200 of the embodiment of the present application may further include a diaphragm 260.
  • the function of the diaphragm 260 is to precisely adjust the amount of light passing through. Therefore, by setting the diaphragm 260, it is beneficial to control the incident angle of the effective light signal reaching the lens 240.
  • the diaphragm 260 is provided on the side of the fourth lens 244 away from the third lens 243 .
  • the distance between the diaphragm 260 and the fourth lens 244 is greater than 0.6 mm and less than 5 mm, for example, the distance between the diaphragm 260 and the fourth lens 244 may be 0.6 mm, 1.0 mm, 3 mm, 5 mm or other values.
  • the distance between the diaphragm 260 and the fourth lens 244 refers to the distance from the diaphragm 260 to the vertex of the fourth light-emitting surface S42 of the fourth lens 245 .
  • the fourth lens 244 modulates the beam, it is limited by the diaphragm 260, and then exits in the form of parallel light with a specific beam diameter.
  • Different positions on the display 220 correspond to different fields of view emitted by the projector 200 ; that is, the lights emitted by different light sources are emitted through the diaphragm 260 as parallel lights with respective corresponding field angles.
  • the diaphragm 260 includes a blocking area and a light-transmitting area, the blocking area is arranged around the periphery of the light-transmitting area, and the light-transmitting area can facilitate the diaphragm 260 to adjust the effective light signal transmitted through the lens 240 .
  • the light-transmitting area is a circular structure, and the light-transmitting area satisfies: 3.5mm ⁇ D ⁇ 6mm, where D is the aperture of the light-transmitting area.
  • the light-transmitting area may be a light-transmitting circular hole, and the diameter of the circular hole may be 3.5 mm, 4.0 mm, 5.0 mm, 6.0 mm or other values.
  • the light-transmitting area may also be other structures, such as the light-transmitting area may be a rectangular structure, a trapezoidal structure, and the like.
  • the structured surface of the diaphragm 260 can be treated as a matte surface, which can prevent light from being reflected and refracted on the structured surface of the diaphragm 260 so that other light rays are mixed into the transmitted light signal transmitted through the lens 240 .
  • FIG. 6 is a schematic diagram of a second structure of a light projector provided by an embodiment of the present application.
  • the light projector 400 in the embodiment of the present application includes a microdisplay 420 and a lens 440, wherein the microdisplay 420 can refer to the relevant description of the display 220 in the above-mentioned embodiment, and details are not repeated here.
  • the lens 440 may include a first lens 441 , a second lens 442 , a third lens 443 and a fourth lens 444 arranged in sequence along the optical axis direction (or the effective optical signal transmission direction), and the first lens 441 is adjacent to the microdisplay 420 set up. It can be understood that the first lens 441 , the second lens 442 , the third lens 443 and the fourth lens 444 are sequentially arranged from the image source side to the imaging side.
  • the first lens 441 is a positive optical power lens, which has a converging effect on the effective optical signal
  • the second lens 442 is a negative optical power lens, which has a divergent effect on the effective optical signal
  • the third lens 443 is a cemented lens, which can reduce chromatic aberration Or correct chromatic aberration
  • the fourth lens 444 is a positive refractive power lens, which has a converging effect on the effective optical signal.
  • the structures of the first lens 441 , the third lens 443 and the fourth lens 444 are respectively the same as those of the first lens 241 , the third lens 243 and the fourth lens 244 in the projection lens 220 shown in FIG. 1 .
  • the third lens 443 and the fourth lens 444 please refer to the descriptions in the above embodiments, and details are not repeated here.
  • the structure of the second lens 442 is different from that of the second lens 242 .
  • the second lens 442 includes a second light incident surface and a second light exit surface opposite to each other, and the second light incident surface is located on the first surface of the first lens 441 .
  • the second light-incident surface is a convex surface formed by protruding from the imaging side toward the image source side
  • the second light-emitting surface is a concave surface formed by concave from the imaging side toward the image source side .
  • the distance between the spherical vertex of the first light incident surface of the first lens 441 and the microdisplay 420 is less than 3 mm, for example, the distance between the spherical vertex of the first light incident surface of the first lens 441 and the microdisplay 420 may be 1 mm, 2mm or 3mm.
  • the distance between the spherical vertex of the first light-emitting surface of the first lens 441 and the spherical vertex of the second light-incident surface of the second lens 442 is less than 0.5 mm, such as 0.2 mm, 0.3 mm or 0.5 mm.
  • the projector 400 shown in FIG. 6 satisfies: 8.6mm ⁇ f ⁇ 10.4mm, 4.2mm ⁇ f1 ⁇ 7.8mm, and 0.48 ⁇ f1/f ⁇ 0.88; -28mm ⁇ f2 ⁇ -14mm, and -3.3 ⁇ f2 /f ⁇ -1.7; -28mm ⁇ f3 ⁇ -12mm, and -3.2 ⁇ f3/f ⁇ -1.4; 3.6mm ⁇ f4 ⁇ 6.4mm, and 0.32 ⁇ f4/f ⁇ 0.72;
  • f is the focal length of the projector 400
  • f1 is the focal length of the first lens 441
  • f2 is the focal length of the second lens 442
  • f3 is the focal length of the third lens 443
  • f4 is the focal length of the fourth lens 444 .
  • the third lens 443 satisfies: -2.1mm ⁇ f31 ⁇ -4.2mm, and -0.42 ⁇ f31/f ⁇ -0.21; 3.6mm ⁇ f32 ⁇ 6.4mm, and 0.32 ⁇ f32/f ⁇ 0.72.
  • f31 is the focal length of the first sub-lens
  • f32 is the focal length of the second sub-lens.
  • the light projector 400 shown in FIG. 6 also satisfies: TTL ⁇ 13mm, where TTL (Total Track Length) is the total optical length of the light projector.
  • TTL Total Track Length
  • the projector 400 that satisfies the above conditions can control the size of the projection lens as a whole, which is beneficial to realize the miniaturization of the projection lens 400 .
  • the total optical length of the projector can be 10.9mm
  • the lens size in the related art is 40mm ⁇ 18mm ⁇ 7mm.
  • the projector that satisfies the above conditions greatly reduces the size of the projector. Overall size.
  • the thickness T1 of the first lens 441 satisfies 1.0mm ⁇ T1 ⁇ 1.9mm, for example, the thickness of the first lens 241 may be 1.0mm, or 1.4mm, or 1.9mm, wherein the thickness of the first lens 441 refers to the first The center thickness of the lens 441.
  • the thickness T2 of the second lens 442 satisfies 0.5mm ⁇ T2 ⁇ 1mm, for example, the thickness of the second lens 442 can be 0.5mm, or 0.8mm, or 1mm, wherein the thickness of the second lens 442 refers to the center of the second lens 442 thickness.
  • the thickness T3 of the third lens 443 satisfies 1.9mm ⁇ T3 ⁇ 4.1mm, for example, the thickness of the third lens 443 can be 1.9mm, or 2.4mm, or 4.1mm, wherein the thickness of the third lens 443 refers to the third lens 443 the center thickness.
  • the thickness T31 of the first sub-lens 4431 satisfies 0.5mm ⁇ T31 ⁇ 0.8mm.
  • the thickness of the first sub-lens 4431 can be 0.5mm, 0.6mm or 0.8mm.
  • the thickness of the first sub-lens 4431 refers to the first sub-lens 4431.
  • the thickness refers to the center thickness of the second sub-lens 4432.
  • the thickness T4 of the fourth lens 444 satisfies 0.6mm ⁇ T4 ⁇ 1.4mm, for example, the thickness of the fourth lens 444 may be 0.6mm, or 1.0mm, or 1.4mm, wherein the thickness of the fourth lens 444 refers to the fourth lens 444 the center thickness.
  • the overall size of the projector 400 can be effectively controlled by reasonably setting the thicknesses between the lenses.
  • the optical projector 400 shown in FIG. 6 also satisfies: tan(FOV/2)/TTL>0.021mm-1, 25° ⁇ FOV ⁇ 32°, where FOV is the diagonal field of view of the optical projector 400 , f is the focal length of the projector 400 .
  • the light projector 400 that satisfies the above conditions can obtain a larger angle of view to meet the requirement of a large depth recognition range.
  • the aperture of the exit pupil of the projector 400 is 3.5mm-6mm, and the maximum optical aperture is 5.4mm-8mm.
  • the refractive index of the first lens 441 is between 1.8-1.9, and the Abbe number is between 32-50.
  • the refractive index of the second lens 442 is between 1.46-1.57, and the Abbe number is between 52-64.
  • the refractive index of the first sub-lens 2431 in the third lens 443 is between 1.78-1.94, and the Abbe number is between 16-36, and the refractive index of the second sub-lens 2432 in the third lens 443 is between 1.74-1.89, and the Abbe number is between 1.74 and 1.89.
  • the refractive index of the fourth lens 444 is between 1.82-1.92, and the Abbe number is between 24-36.
  • the FOV in the diagonal direction is 28°
  • the ratio of the horizontal to vertical field of view is 1:1
  • the total optical length of the lens 440 is TTL is 10.9mm
  • the focal length f of the lens 440 is 9.1mm
  • the maximum optical aperture D is 5.8 mm
  • the exit pupil diameter is 5mm.
  • the micro-display 420 adopts a green light Micro-LED with an effective light-emitting area of 0.26 inches, and an effective light-emitting area of 3.24 mm ⁇ 3.24 mm is used therein.
  • the focal length f1 of the first lens 441 is 6 mm
  • the focal length f2 of the second lens 442 is -20 mm
  • the focal length f3 of the third lens 443 is -21 mm
  • the f31 of the first sub-lens 4431 in the third lens 443 is -2.8mm
  • the focal length f32 of the second sub-lens 4432 in the third lens 443 is 4.7mm
  • the focal length f4 of the fourth lens is 11.4mm.
  • FIG. 7 is a modulation transfer function diagram of the lens in the optical projector shown in FIG. 6
  • FIG. 8 is a field curvature diagram of the lens in the optical projector shown in FIG. 6
  • FIG. 9 is shown in FIG. 6 .
  • FIG. 10 is the defocus curve diagram of the lens in the light projector shown in FIG. 6 .
  • 7 , 8 , 9 and 10 all show relevant parameter graphs of the lens 440 with the parameters shown in Table 2. It can be seen from FIG. 7 to FIG.
  • the imaging quality of the embodiment of the present application is much higher than the Nyquist sampling evaluation of the system, and the distortion and field curvature are limited to a range far smaller than the range that cannot be detected by the human eye, and
  • the assembly and debugging sensitivity of the system is weaker than the accuracy commonly used in current production, which facilitates the mass production process.
  • the optical distortion amount of the lens 240 in the embodiment of the present application is controlled within the range of -2.0% to 2.0%, which illustrates the deformation of the imaging screen of the lens 240 in the embodiment of the present application.
  • the peaks of almost all the curves are near the vertical axis of zero offset, indicating that the defocus characteristics of the lens 240 are excellent, and a larger effective depth of focus value range can be obtained.
  • all the peaks of the defocus characteristic curves are in the higher value region, and the imaging contrast is excellent.
  • the embodiment of the present application further provides a near-eye display system, such as shown in FIG. 11 , which is a schematic structural diagram of the near-eye display system provided by the embodiment of the present application.
  • the near-eye display system 20 may include the projector 200 (or the projector 400 ) as described above, and a waveguide element 600 disposed on the side of the lens 240 away from the display 220 .
  • the display 22 has pixels, each pixel can emit effective light signals of different emission angles, the effective light signals can include image information, and the lens can receive the effective light signals of different emission angles and compare the effective light signals. Modulation is performed so that the effective optical signal generated by one pixel point forms parallel light beams with different exit angles after passing through the lens 230 .
  • the lens 240 can be disposed between the display 220 and the waveguide element 600 , and the lens 240 is located on the side of the outgoing light of the display 220 .
  • the effective optical signal is modulated into a specific optical signal state output, wherein the optical signal entering the lens 240 is a beam with a certain divergence angle emitted by an array composed of pixel points at different positions on the light-emitting surface of the display 220, and the light output after passing through the lens 240
  • the signal is that the exit pupil positions outside the lens 220 overlap, and different pixels correspond to parallel light beams with different exit angles.
  • the set of different exit angles corresponding to all pixels is the field of view of the near-eye display system composed of the display 220 and the lens 240 .
  • the waveguide element 600 can convert the optical signal outputted through the lens 240 into a virtual image after in-coupling, total internal reflection propagation, and out-coupling, etc., and transmit it to the human eye, so that the human eye can view the virtual image.
  • the positional relationship between the projector 200 and the waveguide element 600 in FIG. 11 is only exemplary, and the relationship between the projector 200 and the waveguide element 600 in FIG. 11 is not limited to being arranged in parallel. Tilt a certain angle setting, such as 45 degrees, 60 degrees, or other angle values.

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Abstract

本申请提供一种镜头、投影光机及近眼显示系统，镜头包括沿光轴方向依次排列设置的第一透镜、第二透镜、第三透镜和第四透镜，分别用于会聚显示器所发射出的有效光信号以形成第一透射光信号、分散第一透射光信号以形成第二透射光信号、分散第二透射光信号以形成第三透射光信号、会聚第三透射光信号以形成第四透射光信号。

Description

镜头、投影光机以及近眼显示系统
本申请要求于2020年10月14日提交中国专利局，申请号为202011097931.X、发明名称为“镜头、投影光机以及近眼显示系统”以及申请号为202022286796.5、实用新型名称为“镜头、投影光机以及近眼显示系统”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本申请涉及显示投影技术领域，特别涉及一种镜头、投影光机以及近眼显示系统。
背景技术
随着增强现实技术的不断发展，诸如智能眼镜或智能面罩等头戴式增强现实设备被用户广泛接受和应用。
增强现实设备通常可以包括投影机和摄像头，投影机可以生成虚拟图像，虚拟图像的光线和现实环境的光线可以同时射入佩戴增强现实设备的用户瞳孔内，使得佩戴增强现实设备的用户不仅能够看到现实的事物，还能够看到虚拟的图像。
发明内容
本申请实施例提供一种镜头、投影光机以及近眼显示系统，镜头可以应用于投影光机中，以对投影光机所发射的有效光信号进行调制。
本申请实施例提供一种镜头，包括沿光轴方向依次排列设置的第一透镜、第二透镜、第三透镜和第四透镜，所述第一透镜用于会聚显示器所发射出的有效光信号以形成第一透射光信号，所述第二透镜用于分散所述第一透射光信号以形成第二透射光信号，所述第三透镜用于分散所述第二透射光信号以形成第三透射光信号，所述第四透镜用于会聚所述第三透射光信号以形成第四透射光信号。
本申请实施例提供一种投影光机，包括显示器和镜头，所述镜头为如上申请实施例所述的镜头，所述显示器用于发射有效光信号，所述显示器设置在所述镜头的一侧且与所述第一透镜相邻以使得所述有效光信号可射入所述第一透镜。
本申请实施例提供一种近眼显示系统，包括：
显示器，所述显示器的像素点发射具有不同发射角度的有效光信号，所述有效光信号包括图像信息；
镜头，设置在所述显示器的一侧，用于接收所述有效光信号并对所述有效光信号进行调制，以使一个所述像素点产生的有效光信号经过所述镜头之后形成不同出射角度的平行光束；
波导元件，设置在所述镜头远离所述显示器的一侧，所述波导元件用于接收所述平行光束，并将所述平行光束转换为虚拟图像。
附图说明
图1为本申请实施例提供的投影光机的第一种结构意图。
图2为图1所示投影光机中镜头的调制传递函数图。
图3为图1所示投影光机中镜头的场曲图。
图4为图1所示投影光机中镜头的畸变曲线图。
图5为图1所示投影光机中镜头的离焦曲线图。
图6为本申请实施例提供的投影光机的第二种结构示意图。
图7为图6所示投影光机中镜头的调制传递函数图。
图8为图6所示投影光机中镜头的场曲图。
图9为图6所示投影光机中镜头的畸变曲线图。
图10为图6所示投影光机中镜头的离焦曲线图。
图11为本申请实施例提供的近眼显示系统的结构示意图。
具体实施方式
下面将结合本申请实施例中的附图，对本申请实施例中的技术方案进行清楚、完整地描述。显然，所描述的实施例仅仅是本申请一部分实施例，而不是全部的实施例。基于本申请中的实施例，本领域技术人员在没有做出创造性劳动前提下所获得的所有其他实施例，都属于本申请保护的范围。
本申请实施例提供一种镜头，包括沿光轴方向依次排列设置的第一透镜、第二透镜、第三透镜和第四透镜，所述第一透镜用于会聚显示器所发射出的有效光信号以形成第一透射光信号，所述第二透镜用于分散所述第一透射光信号以形成第二透射光信号，所述第三透镜用于分散所述第二透射光信号以形成第三透射光信号，所述第四透镜用于会聚所述第三透射光信号以形成第四透射光信号。
本申请的一种可选实施例中，所述第一透镜为正光焦度透镜，所述第二透镜为负光焦度透镜，所述第三透镜为胶合透镜且所述胶合透镜的组合光焦度为负值，所述第四透镜为正光焦度透镜。
本申请的一种可选实施例中，所述第三透镜包括相互胶合的第一子透镜和第二子透镜，所述第一子透镜位于所述第二子透镜和所述第二透镜之间且所述第一子透镜为负光焦度透镜，所述第二子透镜位于所述第一子透镜和所述第四透镜之间且所述第二子透镜为正光焦度透镜。
本申请的一种可选实施例中，所述第一子透镜包括相背设置的入射面和第一胶合面，所述入射面朝向所述第三透镜且所述入射面为凹面，所述胶合面为凹面；
所述第二子透镜包括相背设置的第二胶合面和出射面，所述第二胶合面与所述第一胶合面连接，所述第二胶合面为凸面且所述第二胶合面的形状与所述第一胶合面的形状相适配，所述出射面朝向所述第四透镜，且所述出射面为凸面；
所述第二光信号从所述入射面入射，依次经过所述第一胶合面和第二胶合面，并从所述出射面出射以形成所述第三光信号。
本申请的一种可选实施例中，所述第一透镜包括相背设置的第一入光面和第一出光面，所述第一出光面靠近所述第二透镜设置，所述第一入光面和所述第一出光面均为凸面；
所述第二透镜包括相背设置的第二入光面和第二出光面，所述第二入光面位于所述第一出光面和所述第二出光面之间，所述第二入光面为凹面，所述第二出光面为凸面；
所述第四透镜包括相背设置的第三入光面和第三出光面，所述第三入光面位于所述第三透镜和所述第三出光面之间，所述第三入光面为凸面、凹面和平面结构中的一种，所述第三出光面为凸面。
本申请的一种可选实施例中，所述镜头满足：TTL＜14mm，其中TTL为所述镜头的 光学总长度。
本申请的一种可选实施例中，所述镜头的出瞳口径为3.5mm-6mm，所述镜头的最大光学口径为5.4mm-8mm。
本申请的一种可选实施例中，所述镜头满足：tan(FOV/2)/TTL＞0.021mm-1，25°≤FOV≤32°，其中FOV为镜头的对角线方向视场角。
本申请的一种可选实施例中，所述镜头的光学总长度小于14mm，且所述镜头满足：1.0mm≤T1≤2.4mm，0.3mm≤T2≤1mm，1.9mm≤T3≤3.2mm，0.6mm≤T4≤1.4mm；
其中，T1为所述第一透镜的厚度，T2为所述第二透镜的厚度，T3为所述第三透镜的厚度，T4为所述第四透镜的厚度。
本申请的一种可选实施例中，所述第一透镜与第二透镜之间的距离大于1.8mm，所述第三透镜与所述第四透镜之间的距离小于0.8mm。
本申请的一种可选实施例中，所述第一透镜与第二透镜之间的距离小于0.5mm，所述第三透镜与所述第四透镜之间的距离小于0.8mm。
本申请的一种可选实施例中，所述镜头满足：8.6mm≤f≤10.4mm，4.2mm≤f1≤7.8mm，且0.48＜f1/f＜0.88；-28mm≤f2≤-14mm，且-3.3＜f2/f＜-1.7；-28mm≤f3≤-12mm，且-3.2＜f3/f＜-1.4；3.6mm≤f4≤6.4mm，且0.32＜f4/f＜0.72；
其中，f为镜头的焦距，f1为第一透镜的焦距，f2为第二透镜的焦距，f3为第三透镜的焦距，f4为第四透镜的焦距。
本申请的一种可选实施例中，所述第一透镜、所述第二透镜、所述第三透镜和所述第四透镜均采用玻璃材质制成。
本申请实施例还提供一种投影光机，包括显示器和镜头，所述镜头为如上所述的镜头，所述显示器用于发射有效光信号，所述显示器设置在所述镜头的一侧且与所述第一透镜相邻以使得所述有效光信号可射入所述第一透镜。
本申请的一种可选实施例中，所述投影光机还包括光阑，所述光阑设置在所述第四透镜背离第三透镜的一侧且所述光阑与所述镜头同轴设置，所述光阑与所述镜头之间的距离大于0.6mm且小于5mm，所述光阑用于对所述第四透射光信号进行调制以使得透过所述光阑的透射光信号相互平行。
本申请的一种可选实施例中，所述光阑包括遮挡区域和透光区域，所述遮挡区域围设在所述透光区域的周缘，所述透光区域为圆形结构，所述透光区域满足：3.5mm≤D≤6mm，D为透光区域的孔径。
本申请实施例还提供一种近眼显示系统，包括：
显示器，所述显示器的像素点发射具有不同发射角度的有效光信号，所述有效光信号包括图像信息；
镜头，设置在所述显示器的一侧，用于接收所述有效光信号并对所述有效光信号进行调制，以使一个所述像素点产生的有效光信号经过所述镜头之后形成不同出射角度的平行光束；
波导元件，设置在所述镜头远离所述显示器的一侧，所述波导元件用于接收所述平行光束，并将所述平行光束转换为虚拟图像。
本申请的一种可选实施例中，所述镜头包括沿光轴方向依次排列的第一透镜、第二透镜、第三透镜和第四透镜，所述第一透镜与所述显示器相邻设置以使得每一所述像素点所产生的有效光信号可射入所述第一透镜，所述第一透镜用于会聚每一所述像素点所产生的有效光信号以形成多个不同出射角度的第一透射光信号，所述第二透镜用于会聚所述多个第一透射光信号以形成多个不同出射角度的第二透射光信号，所述第三透镜用于分散所述多个第二透射光信号以形成多个不同出射角度的第三透射光信号，所述第四透镜用于分散所述第三透射光信号以形成多个不同出射角度的第四透射光信号，一个所述像素点对应的多个第四透射光信号相互平行。
本申请的一种可选实施例中，所述镜头的光学总长度小于14mm，且所述镜头满足：1.0mm≤T1≤2.4mm，0.3mm≤T2≤1mm，1.9mm≤T3≤3.2mm，0.6mm≤T4≤1.4mm；
其中，T1为所述第一透镜的厚度，T2为所述第二透镜的厚度，T3为所述第三透镜的厚度，T4为所述第四透镜的厚度。
本申请的一种可选实施例中，所述显示器与第一透镜之间的距离小于4mm，所述第一透镜与第二透镜之间的距离大于1.8mm，所述第三透镜与所述第四透镜之间的距离小于0.8mm。
本申请实施例提供一种投影光机，该投影光机用于生成虚拟图像。如图1所示，图1为本申请实施例提供的投影光机的第一种结构意图。投影光机200可以投射虚拟图像。投影光机200包括显示器220和镜头240，镜头240设置在显示器220的一侧，显示器220可以发射光线，其中生成虚拟图像的光信号为有效光信号，有效光信号可以透射过镜头240，镜头240可以对有效光信号进行矫正，以消除各种像差，从而提高投影光机200所要投射的虚拟图像的成像质量。镜头240可以包括沿光轴方向(或者说有效光信号的传输方向)依次排列的第一透镜241、第二透镜242、第三透镜243和第四透镜244，第一透镜241与显示器220相邻设置。可以理解的是，第一透镜241、第二透镜242、第三透镜243和第四透镜244从像源侧至成像侧依次排列。
其中，第一透镜241可以接收显示器220所发射的有效光信号并会聚有效光信号以形成第一透射光信号，第二透镜242可以接收并分散第一透射光信号第一透射光信号以形成第二透射光信号，第三透镜243可以接收并分散第二透射光信号以形成第三透射光信号，第四透镜244可以接收并会聚第三透射光信号以形成第四透射光信号。例如，第一透镜241为正光焦度透镜，对有效光信号有会聚作用，有效光信号经过第一透镜241后可形成第一透射光信号；第二透镜242为负光焦度透镜，对有效光信号具有发散作用，第一透射光信号经过第二透镜242后可形成第二透射光信号；第三透镜243为胶合透镜且胶合透镜的组合光焦度为负值，第三透镜243对第三透射光信号有分散作用，第二透射光信号经过第三透镜243后可形成第三透射光信号，可以减少色差或校正色差；第四透镜为正光焦度透镜，对有效光信号有会聚作用，第三透射光信号经过第四透镜244后可形成第四透射光信号。
本申请实施例的微型显示器所发射的有效光信号可以依次经过第一透镜241、第二透镜242、第三透镜243和第四透镜244，四个透镜可以对有效光信号进行调制以减小像差，进而提高投影光机200所投射的虚拟图像的成像效果。
请继续参阅图1，第三透镜243可以由两个单片镜片通过胶合而成。比如第三透镜243 可以包括第一子透镜2431和第二子透镜2432，第一子透镜2431中的一个表面和第二子透镜2432中的一个表面相适配，以使得第一子透镜2431中的一个表面和第二子透镜2432中的一个表面可以相互胶合在一起。第一子透镜2431位于第二子透镜2432和第二透镜242之间，第一子透镜2431为负光焦度透镜，对第二透射光信号具有发散作用。第二子透镜2432位于第一子透镜2431和第四透镜244之间，第二子透镜2432为正光焦度透镜，对透射过第一子透镜2431的光信号具有会聚作用。
本申请实施例中的显示器220可以为微型显示器，比如显示器220可以为有机发光二极管(Organic Light-Emitting Diode，OLED)显示器或微型液晶显示屏(liquid crystal display，LCD)，在工作功率条件下Micro-OLED的亮度小于5000nits，LCD的亮度小于15000nits。本申请实施例中的显示器220还可以是微型发光二极管(Micro Light Emitting Diode，Micro-LED)显示器，比如可以为绿光Micro-LED，也可以是其他单色Micro-LED或白光复色Micro-LED。相比于Micro-OLED和LCD，Micro-LED的亮度可达2000000nits，远远高于Micro-OLED和LCD。此外，由于Micro-LED是自发光光源，搭配Micro-LED的投影系统具有更好的对比度及更好的显示延迟。
显示器220的有效发光区域对角线尺寸为0.17inch-0.19inch，有效发光区域长宽比为1:1。在其他一些实施例中，或显示器220的有效发光区域对角线尺寸为0.25inch-0.29inch，有效发光区域长宽比为16:9。其中，显示器220的有效发光表面外设置有玻璃盖板，玻璃盖板可以以独立形式存在或集成封装在显示器220的形式存在。玻璃盖板厚度范围为0.3mm-0.8mm。
显示器220在工作过程中会产生热量，显示器220所产生的热量会传导至镜头240中。为了提高镜头240的热稳定性，本申请实施例的四个透镜均采用玻璃材质制成，相对于塑料材质制成的透镜，玻璃材质制成的透镜的热稳定性较好，受热不容易产生形变。本申请实施例的第一透镜241、第二透镜242、第一子透镜2431、第二子透镜2432和第四透镜244均为球面透镜，采用玻璃球面的方案进行小尺寸光学系统设计，可以保证大范围温度变化的光学系统稳定性的同时，实现更小的制作及组装成本。
如图1所示，第一透镜241包括相背设置的第一入光面S11和第一出光面S12，第一出光面S12靠近第二透镜242设置，第一入光面S11和第一出光面S12均为凸面。可以理解的是，第一透镜241的第一入光面S11和第一出光面S12均为球面结构，且第一入光面S11为从成像侧朝向像源侧凸出的表面，第一出光面S12为从像源侧朝向成像侧凸出的表面。
第二透镜242包括相背设置的第二入光面S21和第二出光面S22，第二入光面S21位于第一出光面S12和第二出光面S22之间，第二入光面S21为凹面，第二出光面S22为凸面。可以理解的是，第二透镜242的第二入光面S21和第二出光面S22均为球面结构，第二入光面S21为从像源侧朝向成像侧凹陷的表面，第二出光面S22为从像源侧朝向成像侧凸出的表面。
第三透镜243包括相背设置的第三入光面S31和第三出光面S32，第三入光面S31位于第二出光面S22和第三出光面S32之间，第三入光面S31为凹面，第三出光面S32为凸面。可以理解的是，第三透镜243的第三入光面S31和第三出光面S32均为球面结构，第 三入光面S31为从像源侧朝向成像侧凹陷的表面，第三出光面S32为从像源侧朝向成像侧凸出的表面。其中，第一子透镜2431包括相背设置的第三入光面S31和第一连接面S33，第一连接面S33为凹面，第一连接面S33为从成像侧朝向像源侧的方向凹陷形成。第二子透镜2432包括相背设置的第二连接面S34和第三出光面S32，第二连接面S34与第一连接面S33连接，第二连接面S34为凸面，且第二连接面S34为从像源侧朝向成像侧的方向凸出形成。需要说明的是，第一连接面S33和第二连接面S34的大小形状相适配，图1所示的第一连接面S33和第二连接面S34相互重叠。
需要说明的是，第三出光面S32的结构并不限于此，比如第三出光面S32也可以为凹面，或者平面。第四透镜244包括相背设置的第四入光面S41和第四出光面S42，第四入光面S41位于第三出光面S32和第四出光面S42之间，第四入光面S41可以为凸面、凹面和平面结构中的一种，比如第四入光面S41可以凸面，第四入光面S41为从成像侧朝向像源侧方向凸出形成的结构。第四出光面S42为凸面，第四出光面S42为从像源侧朝向成像侧方向凸出形成的结构。
其中，第四出光面S42和第三出光面S32均为球面结构，第四出光面S42的球面顶点与第三出光面S32的球面顶点之间的距离小于0.8mm，比如第四出光面S42的球面顶点与第三出光面S32的球面顶点之间的距离可以为0.8mm，0.5mm或0.2mm等。
本申请实施例中第一入光面S11为球面结构，第一入光面S11的球面顶点与显示器220之间的距离小于4mm，比如第一入光面S11与显示器220之间的距离可以为4mm、3.5mm、3mm、2mm或1mm等。在其他一些实施例中，第一入光面S11的球面顶点与显示器220之间的距离小于3mm。第一出光面S12和第二入光面S12均为球面结构，第一出光面S12的球面顶点与第二入光面S12的球面顶点之间的距离小于1.8mm，比如1.8mm、1.5mm、1mm或0.5mm等。
如图1所示的投影光机200满足：8.8mm≤f≤10.6mm，4.5mm≤f1≤7.3mm，且0.46＜f1/f＜0.78；-11.9mm≤f2≤-6.8mm，且-1.3＜f2/f＜-0.7；-40mm≤f3≤-18mm，且-3.6＜f3/f＜-1.8；8mm≤f4≤15mm，且0.9＜f4/f＜1.4。其中，f为投影光机的焦距，f1为第一透镜的焦距，f2为第二透镜的焦距，f3为第三透镜的焦距，f4为第四透镜的焦距。
其中，第三透镜243满足：-2.1mm≤f31≤-4.4mm，且-0.46＜f31/f＜-0.24；3.6mm≤f32≤7.1mm，且0.35＜f32/f＜0.66。其中，f31为第一子透镜的焦距，f32为第二子透镜的焦距。
如图1所示的投影光机200还满足：TTL＜14mm，其中TTL(Total Track Length)为投影光机的光学总长度。满足上述条件的投影光机200可以从整体上控制投影镜头的尺寸，有利于实现投影镜头200的小型化。比如，投影光机的光学总长度可以为11.8mm，相关技术中的镜头尺寸为40mm×18mm×7mm，满足上述条件的投影光机相比于相关技术中的镜头，大幅降低了投影光机的整机尺寸。
其中，第一透镜241的厚度T1满足1.0mm≤T1≤2.4mm，比如第一透镜241的厚度可以为1.0mm，或者1.5mm，或者2.0mm，或者2.4mm，其中第一透镜241的厚度指的是第一透镜241的中心厚度。
第二透镜242的厚度T2满足0.3mm≤T2≤1mm，比如第二透镜242的厚度可以为0.3mm，或者0.5mm，或者0.8mm，或者1mm，其中第二透镜242的厚度指的是第二透镜 242的中心厚度。
第三透镜243的厚度T3满足1.9mm≤T3≤3.2mm，比如第三透镜243的厚度可以为1.9mm，或者2.5mm，或者3.0mm，或者3.2mm，其中第三透镜243的厚度指的是第三透镜243的中心厚度。其中，第一子透镜2431的厚度T31满足0.4mm≤T31≤0.8mm，比如，第一子透镜2431的厚度可以为0.4mm、0.5mm或0.8mm,第一子透镜2431的厚度指的是第一子透镜2431的中心厚度；第二子透镜2432的厚度T32满足1.7mm≤T32≤2.4mm，比如第二子透镜2432的厚度T32可以为1.7mm、2.0mm或2.4mm,第二子透镜2432的厚度指的是第二子透镜2432的中心厚度。
第四透镜244的厚度T4满足0.6mm≤T4≤1.4mm，比如第四透镜244的厚度可以为0.6mm，或者1.0mm，或者1.4mm，其中第四透镜244的厚度指的是第四透镜244的中心厚度。
本申请实施例通过合理设置各个透镜之间的厚度可以有效控制投影光机200的整体尺寸。
如图1所示的投影光机200还满足：tan(FOV/2)/TTL>0.021mm-1，25°≤FOV≤32°，其中FOV为投影光机200的对角线方向视场角，f为投影光机200的焦距。满足上述条件的投影光机200可以获得较大的视场角，以满足大深度识别范围的需求。投影光机200的出瞳口径为3.5mm-6mm，最大光学口径为5.4mm-8mm。其中，第一透镜241的折射率介于1.75-1.88，阿贝数介于38-54。第二透镜242的折射率介于1.46-1.57，阿贝数介于58-69。第三透镜243中第一子透镜2431的折射率介于1.88-1.98，阿贝数介于16-36，第三透镜243中第二子透镜2432的折射率介于1.8-1.88，阿贝数介于26-36。第四透镜244的折射率介于1.88-1.98，阿贝数介于16-36。
为进一步地说明图1所示的投影光机200的成像效果，本申请实施例的镜头的参数如下表1所示：
Figure PCTCN2021110306-appb-000001
其中，对角线方向视场角FOV为28，水平与垂直视场比为1:1，镜头240光学总长度TTL为11.8mm，镜头240的焦距f为9.4mm，最大光学口径D为6.8mm，出瞳口径为5mm。
第一透镜241的焦距f1为5.9mm，第二透镜242的焦距f2为-9.4mm，第三透镜243的焦距f3为-26mm，第三透镜243中第一子透镜2431的焦距f31为-3.2mm，第三透镜243中第二子透镜2432的焦距f32为5.3mm，第四透镜244的焦距f4为10.9mm。
请参照图2至图5，图2为图1所示投影光机中镜头的调制传递函数图，图3为图1所示投影光机中镜头的场曲图，图4为图1所示投影光机中镜头的畸变曲线图，图5为图1所示投影光机中镜头的离焦曲线图。图2、图3、图4和图5均示出了具有如表1所示参数的镜头240的相关参数图。其中，调制传递函数(Modulation Transfer Function，MTF)是指调制度与图像内每毫米线对数之间的关系，可以用于评价镜头的成像质量，可以体现为成像对原物体细节的还原能力；场曲图可以表现镜头所成像面的弯曲度及翘曲度；畸变图可以表示镜头成像画面的变形程度；离焦曲线可以表示镜头的焦深信息。从图2至图5可以看出，本申请实施例的具有远高于系统奈奎斯特采样评价的成像质量，畸变及场曲都限制在远小于不会被人眼察觉范围之内，且系统的组装调试敏感度弱于当前生产常用的精度，便于进行量产流程。
从图2所示的调制传递函数图中可以看出，各个视场的MTF曲线变化趋势几乎一致，且MTF曲线从高频到低频都没有出现零点，信息被很好地保存下来,能够用适当的滤波函数复原成清晰图像，说明本申请实施例的镜头240具有良好的分辨率及解像能力。从图3所示的场曲图中可以看出，两条曲线之间的间距比较小，说明本申请实施例的镜头240所成像面的弯曲度及翘曲度都比较小，场曲得到了良好的矫正。从图4所示的畸变图中可以看出，本申请实施例的镜头240的光学畸变量被控制在-1.0％至1.0％的范围内，说明本申请实施例的镜头240的成像画面的变形程度比较小。从图5所示的离焦曲线图中可以看出，几乎所有曲线的峰值都在零偏移垂轴附近，说明镜头240离焦特性为优秀，可以能够得到一个更大的有效焦深值范围，而且所有的离焦特性曲线的峰值都处于较高值区域，成像的对比度优秀。
请继续参阅图1，本申请实施例的投影光机200还可以包括光阑260，光阑260的作用在于精确调整通光量，为了在光线较暗的场景下拍到清晰的图片，需要较大的光通量镜头，因此通过设置光阑260，有利于控制到达透过镜头240的有效光信号的入射角度。光阑260设置在第四透镜244背离第三透镜243的一侧。而且，光阑260与第四透镜244之间的距离大于0.6mm且小于5mm，比如光阑260与第四透镜244之间的距离可以为0.6mm、1.0mm、3mm、5mm或其他数值的距离。其中，光阑260与第四透镜244之间的距离指的光阑260至第四透镜245的第四出光面S42的顶点的距离。第四透镜244进行光束调制后经由光阑260限制，以特定光束口径的平行光的形式出射。显示器220上不同位置对应投影光机200出射的不同视场；即不同发光源发出的光以各自对应的视场角度的平行光经由光阑260出射。
光阑260包括遮挡区域和透光区域，所述遮挡区域围设在所述透光区域的周缘，透光区域可以方便光阑260对透过镜头240的有效光信号的调节。所述透光区域为圆形结构，所述透光区域满足：3.5mm≤D≤6mm，D为透光区域的孔径。比如，透光区域可以为可透光的圆孔，该圆孔的孔径可以为3.5mm、4.0mm、5.0mm、6.0mm或其他数值。当然，所述透光区域也可以为其他结构，诸如所述透光区域可以为矩形结构、梯形结构等。光阑260 的结构表面可以处理为消光表面，可以防止光线在光阑260的结构表面发生反射、折射而使得其他光线混入透过镜头240的透射光信号中。
如图6所示，图6为本申请实施例提供的投影光机的第二种结构示意图。本申请实施例的投影光机400包括微型显示器420和镜头440，其中微型显示器420可以参照上述实施例中显示器220的相关描述，在此不再赘述。
镜头440可以包括沿光轴方向(或者说有效光信号传输方向)依次排列的第一透镜441、第二透镜442、第三透镜443和第四透镜444，第一透镜441与微型显示器420相邻设置。可以的理解是，第一透镜441、第二透镜442、第三透镜443和第四透镜444从像源侧至成像侧依次排列。其中，第一透镜441为正光焦度透镜，对有效光信号有会聚作用；第二透镜442为负光焦度透镜，对有效光信号具有发散作用；第三透镜443为胶合透镜，可以减少色差或校正色差；第四透镜444为正光焦度透镜，对有效光信号有会聚作用。
其中，第一透镜441、第三透镜443和第四透镜444的结构分别与图1所示投影镜头220中的第一透镜241、第三透镜243和第四透镜244的结构相同，第一透镜441、第三透镜443和第四透镜444的相关描述请参照上述实施例中的描述，在此不再赘述。
第二透镜442的结构与第二透镜242的结构不同，所述第二透镜442包括相背设置的第二入光面和第二出光面，第二入光面位于第一透镜441的第一出光面和第二透镜442的第二出光面之间，第二入光面为从成像侧朝像源侧凸出形成的凸面，第二出光面为从成像侧朝像源侧凹陷形成的凹面。
第一透镜441的第一入光面的球面顶点与微型显示器420之间的距离小于3mm，比如第一透镜441的第一入光面的球面顶点与微型显示器420之间的距离可以为1mm、2mm或3mm。第一透镜441的第一出光面的球面顶点与第二透镜442的第二入光面的球面顶点之间的距离小于0.5mm，比如可以为0.2mm、0.3mm或0.5mm。
如图6所示的投影光机400满足：8.6mm≤f≤10.4mm，4.2mm≤f1≤7.8mm，且0.48＜f1/f＜0.88；-28mm≤f2≤-14mm，且-3.3＜f2/f＜-1.7；-28mm≤f3≤-12mm，且-3.2＜f3/f＜-1.4；3.6mm≤f4≤6.4mm，且0.32＜f4/f＜0.72；
其中，f为投影光机400的焦距，f1为第一透镜441的焦距，f2为第二透镜442的焦距，f3为第三透镜443的焦距，f4为第四透镜444的焦距。
其中，第三透镜443满足：-2.1mm≤f31≤-4.2mm，且-0.42＜f31/f＜-0.21；3.6mm≤f32≤6.4mm，且0.32＜f32/f＜0.72。其中，f31为第一子透镜的焦距，f32为第二子透镜的焦距。
如图6所示的投影光机400还满足：TTL＜13mm，其中TTL(Total Track Length)为投影光机的光学总长度。满足上述条件的投影光机400可以从整体上控制投影镜头的尺寸，有利于实现投影镜头400的小型化。比如，投影光机的光学总长度可以为10.9mm，相关技术中的镜头尺寸为40mm×18mm×7mm，满足上述条件的投影光机相比于相关技术中的镜头，大幅降低了投影光机的整机尺寸。
其中，第一透镜441的厚度T1满足1.0mm≤T1≤1.9mm，比如第一透镜241的厚度可以为1.0mm，或者1.4mm，或者1.9mm，其中第一透镜441的厚度指的是第一透镜441的中心厚度。
第二透镜442的厚度T2满足0.5mm≤T2≤1mm，比如第二透镜442的厚度可以为 0.5mm，或者0.8mm，或者1mm，其中第二透镜442的厚度指的是第二透镜442的中心厚度。
第三透镜443的厚度T3满足1.9mm≤T3≤4.1mm，比如第三透镜443的厚度可以为1.9mm，或者2.4mm，或者4.1mm，其中第三透镜443的厚度指的是第三透镜443的中心厚度。其中，第一子透镜4431的厚度T31满足0.5mm≤T31≤0.8mm，比如，第一子透镜4431的厚度可以为0.5mm、0.6mm或0.8mm,第一子透镜4431的厚度指的是第一子透镜4431的中心厚度；第二子透镜4432的厚度T32满足1.4mm≤T32≤2.3mm，比如第二子透镜4432的厚度T32可以为1.4mm、1.8mm或2.3mm,第二子透镜432的厚度指的是第二子透镜4432的中心厚度。
第四透镜444的厚度T4满足0.6mm≤T4≤1.4mm，比如第四透镜444的厚度可以为0.6mm，或者1.0mm，或者1.4mm，其中第四透镜444的厚度指的是第四透镜444的中心厚度。
本申请实施例通过合理设置各个透镜之间的厚度可以有效控制投影光机400的整体尺寸。
如图6所示的投影光机400还满足：tan(FOV/2)/TTL>0.021mm-1，25°≤FOV≤32°，其中FOV为投影光机400的对角线方向视场角，f为投影光机400的焦距。满足上述条件的投影光机400可以获得较大的视场角，以满足大深度识别范围的需求。投影光机400的出瞳口径为3.5mm-6mm，最大光学口径为5.4mm-8mm。
其中，第一透镜441的折射率介于1.8-1.9，阿贝数介于32-50。第二透镜442的折射率介于1.46-1.57，阿贝数介于52-64。第三透镜443中第一子透镜2431的折射率介于1.78-1.94，阿贝数介于16-36，第三透镜443中第二子透镜2432的折射率介于1.74-1.89，阿贝数介于36-52。第四透镜444的折射率介于1.82-1.92，阿贝数介于24-36。
为进一步地说明图2所示的投影光机400的成像效果，本申请实施例的镜头的参数如下表2所示：
Figure PCTCN2021110306-appb-000002
其中，对角线方向视场角为FOV为28°水平与垂直视场比为1:1，镜头440光学总长 度TTL为10.9mm，镜头440的焦距f为9.1mm，最大光学口径D为5.8mm，出瞳口径为5mm。本申请实施例中，微型显示器420采用有效发光区域为0.26英寸的绿光Micro-LED，使用了其中的3.24mm×3.24mm的有效发光区域。
本申请实施例中，第一透镜441的焦距f1为6mm，第二透镜442的焦距f2为-20mm，第三透镜443焦距f3为-21mm，第三透镜443中第一子透镜4431的f31为-2.8mm，第三透镜443中第二子透镜4432焦距f32为4.7mm，第四透镜的焦距f4为11.4mm。
请参照图7至图10，图7为图6所示投影光机中镜头的调制传递函数图，图8为图6所示投影光机中镜头的场曲图，图9为图6所示投影光机中镜头的畸变曲线图，图10为图6所示投影光机中镜头的离焦曲线图。图7、图8、图9和图10均示出了具有如表2所示参数的镜头440的相关参数图。从图7至图10可以看出，本申请实施例的具有远高于系统奈奎斯特采样评价的成像质量，畸变及场曲都限制在远小于不会被人眼察觉范围之内，且系统的组装调试敏感度弱于当前生产常用的精度，便于进行量产流程。
从图2所示的调制传递函数图中可以看出，各个视场的MTF曲线变化趋势几乎一致，且MTF曲线从高频到低频都没有出现零点，信息被很好地保存下来,能够用适当的滤波函数复原成清晰图像，说明本申请实施例的镜头240具有良好的分辨率及解像能力。从图3所示的场曲图中可以看出，两条曲线之间的间距比较小，说明本申请实施例的镜头240所成像面的弯曲度及翘曲度都比较小，场曲得到了良好的矫正。从图4所示的畸变图中可以看出，本申请实施例的镜头240的光学畸变量被控制在-2.0％至2.0％的范围内，说明本申请实施例的镜头240的成像画面的变形程度比较小。从图5所示的离焦曲线图中可以看出，几乎所有曲线的峰值都在零偏移垂轴附近，说明镜头240离焦特性为优秀，可以能够得到一个更大的有效焦深值范围，而且所有的离焦特性曲线的峰值都处于较高值区域，成像的对比度优秀。
本申请实施例还另外提供一种近眼显示系统，诸如图11所示，图11为本申请实施例提供的近眼显示系统的结构示意图。近眼显示系统20可以包括如上所述的投影光机200(也可以是投影光机400)，以及波导元件600，波导元件600设置在镜头240背离显示器220的一侧。结合图1所示，显示器22具有像素点，每一像素点均可以发射不同发射角度的有效光信号，有效光信号可以包括图像信息，镜头可以接收不同发射角度的有效光信号并对有效光信号进行调制，以使得一个像素点所产生的有效光信号经过镜头230之后形成不同出射角度的平行光束。
可以理解的是，镜头240可以设置在显示器220和波导元件600之间，镜头240位于显示器220的出射光的一侧，镜头240可以对显示器220发出的有效光信号进行调制，使全部进入镜头240的有效光信号调制为特定的光信号状态输出，其中进入镜头240的光信号为显示器220发光面上不同位置像素点组成的阵列发出的带有一定发散角度的光束，经过镜头240后输出的光信号为在镜头220外部出瞳位置相重叠，且不同像素点对应不同出射角度的平行光束，全部像素点对应的不同出射角度的集合为显示器220与镜头240组成近眼显示系统的视场。波导元件600可以将经过镜头240出射的光信号发生耦入、内部全反射传播、耦出等作用后转换为虚拟图像并传递至人眼，使得人眼可观看到虚拟图像。。需要说明的是，图11的投影光机200和波导元件600之间的位置关系仅为示例性地，图11 的投影光机200和波导元件600之间的并不限于平行设置，比如也可以倾斜一定的角度设置，比如45度、60度或其他角度值。
以上对本申请实施例提供的镜头、投影光机以及近眼显示系统进行了详细介绍。本文中应用了具体个例对本申请的原理及实施方式进行了阐述，以上实施例的说明只是用于帮助理解本申请。同时，对于本领域的技术人员，依据本申请的思想，在具体实施方式及应用范围上均会有改变之处，综上所述，本说明书内容不应理解为对本申请的限制。

Claims (20)

  1. 一种镜头，其中，包括沿光轴方向依次排列设置的第一透镜、第二透镜、第三透镜和第四透镜，所述第一透镜用于会聚显示器所发射出的有效光信号以形成第一透射光信号，所述第二透镜用于分散所述第一透射光信号以形成第二透射光信号，所述第三透镜用于分散所述第二透射光信号以形成第三透射光信号，所述第四透镜用于会聚所述第三透射光信号以形成第四透射光信号。
  2. 根据权利要求1所述的镜头，其中，所述第一透镜为正光焦度透镜，所述第二透镜为负光焦度透镜，所述第三透镜为胶合透镜且所述胶合透镜的组合光焦度为负值，所述第四透镜为正光焦度透镜。
  3. 根据权利要求2所述的镜头，其中，所述第三透镜包括相互胶合的第一子透镜和第二子透镜，所述第一子透镜位于所述第二子透镜和所述第二透镜之间且所述第一子透镜为负光焦度透镜，所述第二子透镜位于所述第一子透镜和所述第四透镜之间且所述第二子透镜为正光焦度透镜。
  4. 根据权利要求3所述的镜头，其中，所述第一子透镜包括相背设置的入射面和第一胶合面，所述入射面朝向所述第三透镜且所述入射面为凹面，所述胶合面为凹面；
    所述第二子透镜包括相背设置的第二胶合面和出射面，所述第二胶合面与所述第一胶合面连接，所述第二胶合面为凸面且所述第二胶合面的形状与所述第一胶合面的形状相适配，所述出射面朝向所述第四透镜，且所述出射面为凸面；
    所述第二光信号从所述入射面入射，依次经过所述第一胶合面和第二胶合面，并从所述出射面出射以形成所述第三光信号。
  5. 根据权利要求1至4任一项所述的镜头，其中，所述第一透镜包括相背设置的第一入光面和第一出光面，所述第一出光面靠近所述第二透镜设置，所述第一入光面和所述第一出光面均为凸面；
    所述第二透镜包括相背设置的第二入光面和第二出光面，所述第二入光面位于所述第一出光面和所述第二出光面之间，所述第二入光面为凹面，所述第二出光面为凸面；
    所述第四透镜包括相背设置的第三入光面和第三出光面，所述第三入光面位于所述第三透镜和所述第三出光面之间，所述第三入光面为凸面、凹面和平面结构中的一种，所述第三出光面为凸面。
  6. 根据权利要求1至4任一项所述的镜头，其中，所述镜头满足：TTL＜14mm，其中TTL为所述镜头的光学总长度。
  7. 根据权利要求6所述的镜头，其中，所述镜头的出瞳口径为3.5mm-6mm，所述镜头的最大光学口径为5.4mm-8mm。
  8. 根据权利要求6所述的镜头，其中，所述镜头满足：tan(FOV/2)/TTL＞0.021mm-1，25°≤FOV≤32°，其中FOV为镜头的对角线方向视场角。
  9. 根据权利要求1至4任一项所述的镜头，其中，所述镜头的光学总长度小于14mm，且所述镜头满足：1.0mm≤T1≤2.4mm，0.3mm≤T2≤1mm，1.9mm≤T3≤3.2mm，0.6mm≤T4≤1.4mm；
    其中，T1为所述第一透镜的厚度，T2为所述第二透镜的厚度，T3为所述第三透镜的 厚度，T4为所述第四透镜的厚度。
  10. 根据权利要求9所述的镜头，其中，所述第一透镜与第二透镜之间的距离大于1.8mm，所述第三透镜与所述第四透镜之间的距离小于0.8mm。
  11. 根据权利要求9所述的镜头，其中，所述第一透镜与第二透镜之间的距离小于0.5mm，所述第三透镜与所述第四透镜之间的距离小于0.8mm。
  12. 根据权利要求9所述的镜头，其中，所述镜头满足：8.6mm≤f≤10.4mm，4.2mm≤f1≤7.8mm，且0.48＜f1/f＜0.88；-28mm≤f2≤-14mm，且-3.3＜f2/f＜-1.7；-28mm≤f3≤-12mm，且-3.2＜f3/f＜-1.4；3.6mm≤f4≤6.4mm，且0.32＜f4/f＜0.72；
    其中，f为镜头的焦距，f1为第一透镜的焦距，f2为第二透镜的焦距，f3为第三透镜的焦距，f4为第四透镜的焦距。
  13. 根据权利要求1至4任一项所述的镜头，其中，所述第一透镜、所述第二透镜、所述第三透镜和所述第四透镜均采用玻璃材质制成。
  14. 一种投影光机，其中，包括显示器和镜头，所述镜头为权利要求1至13任一项所述的镜头，所述显示器用于发射有效光信号，所述显示器设置在所述镜头的一侧且与所述第一透镜相邻以使得所述有效光信号可射入所述第一透镜。
  15. 根据权利要求14所述的投影光机，其中，所述投影光机还包括光阑，所述光阑设置在所述第四透镜背离第三透镜的一侧且所述光阑与所述镜头同轴设置，所述光阑与所述镜头之间的距离大于0.6mm且小于5mm，所述光阑用于对所述第四透射光信号进行调制以使得透过所述光阑的透射光信号相互平行。
  16. 根据权利要求15所述的光学系统，其中，所述光阑包括遮挡区域和透光区域，所述遮挡区域围设在所述透光区域的周缘，所述透光区域为圆形结构，所述透光区域满足：3.5mm≤D≤6mm，D为透光区域的孔径。
  17. 一种近眼显示系统，其中，包括：
    显示器，所述显示器的像素点发射具有不同发射角度的有效光信号，所述有效光信号包括图像信息；
    镜头，设置在所述显示器的一侧，用于接收所述有效光信号并对所述有效光信号进行调制，以使一个所述像素点产生的有效光信号经过所述镜头之后形成不同出射角度的平行光束；
    波导元件，设置在所述镜头远离所述显示器的一侧，所述波导元件用于接收所述平行光束，并将所述平行光束转换为虚拟图像。
  18. 根据权利要求17所述的近眼显示系统，其中，所述镜头包括沿光轴方向依次排列的第一透镜、第二透镜、第三透镜和第四透镜，所述第一透镜与所述显示器相邻设置以使得每一所述像素点所产生的有效光信号可射入所述第一透镜，所述第一透镜用于会聚每一所述像素点所产生的有效光信号以形成多个不同出射角度的第一透射光信号，所述第二透镜用于会聚所述多个第一透射光信号以形成多个不同出射角度的第二透射光信号，所述第三透镜用于分散所述多个第二透射光信号以形成多个不同出射角度的第三透射光信号，所述第四透镜用于分散所述第三透射光信号以形成多个不同出射角度的第四透射光信号，一个所述像素点对应的多个第四透射光信号相互平行。
  19. 根据权利要求18所述的近眼显示系统，其中，所述镜头的光学总长度小于14mm，且所述镜头满足：1.0mm≤T1≤2.4mm，0.3mm≤T2≤1mm，1.9mm≤T3≤3.2mm，0.6mm≤T4≤1.4mm；
    其中，T1为所述第一透镜的厚度，T2为所述第二透镜的厚度，T3为所述第三透镜的厚度，T4为所述第四透镜的厚度。
  20. 根据权利要求19所述的近眼显示系统，其中，所述显示器与第一透镜之间的距离小于4mm，所述第一透镜与第二透镜之间的距离大于1.8mm，所述第三透镜与所述第四透镜之间的距离小于0.8mm。
PCT/CN2021/110306 2020-10-14 2021-08-03 镜头、投影光机以及近眼显示系统 WO2022078023A1 (zh)

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