WO2021258932A1 - 平板镜头以及光学成像系统 - Google Patents

平板镜头以及光学成像系统 Download PDF

Info

Publication number
WO2021258932A1
WO2021258932A1 PCT/CN2021/094758 CN2021094758W WO2021258932A1 WO 2021258932 A1 WO2021258932 A1 WO 2021258932A1 CN 2021094758 W CN2021094758 W CN 2021094758W WO 2021258932 A1 WO2021258932 A1 WO 2021258932A1
Authority
WO
WIPO (PCT)
Prior art keywords
mirror
area
reflecting
flat
reflection
Prior art date
Application number
PCT/CN2021/094758
Other languages
English (en)
French (fr)
Inventor
程芳
洪涛
周振兴
Original Assignee
京东方科技集团股份有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 京东方科技集团股份有限公司 filed Critical 京东方科技集团股份有限公司
Priority to US17/778,038 priority Critical patent/US20220390727A1/en
Publication of WO2021258932A1 publication Critical patent/WO2021258932A1/zh

Links

Images

Classifications

    • 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
    • G02B17/00—Systems with reflecting surfaces, with or without refracting elements
    • G02B17/02—Catoptric systems, e.g. image erecting and reversing system
    • G02B17/06—Catoptric systems, e.g. image erecting and reversing system using mirrors only, i.e. having only one curved mirror
    • G02B17/0626—Catoptric systems, e.g. image erecting and reversing system using mirrors only, i.e. having only one curved mirror using three curved mirrors
    • G02B17/0642—Catoptric systems, e.g. image erecting and reversing system using mirrors only, i.e. having only one curved mirror using three curved mirrors off-axis or unobscured systems in which not all of the mirrors share a common axis of rotational symmetry, e.g. at least one of the mirrors is warped, tilted or decentered with respect to the other elements
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B13/00—Optical objectives specially designed for the purposes specified below
    • G02B13/001—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B13/00—Optical objectives specially designed for the purposes specified below
    • G02B13/001—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras
    • G02B13/0055—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras employing a special optical element
    • G02B13/0065—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras employing a special optical element having a beam-folding prism or mirror
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B13/00—Optical objectives specially designed for the purposes specified below
    • G02B13/18—Optical objectives specially designed for the purposes specified below with lenses having one or more non-spherical faces, e.g. for reducing geometrical aberration
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B17/00—Systems with reflecting surfaces, with or without refracting elements
    • G02B17/008—Systems specially adapted to form image relays or chained systems
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B17/00—Systems with reflecting surfaces, with or without refracting elements
    • G02B17/02—Catoptric systems, e.g. image erecting and reversing system
    • G02B17/06—Catoptric systems, e.g. image erecting and reversing system using mirrors only, i.e. having only one curved mirror
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B17/00—Systems with reflecting surfaces, with or without refracting elements
    • G02B17/02—Catoptric systems, e.g. image erecting and reversing system
    • G02B17/06—Catoptric systems, e.g. image erecting and reversing system using mirrors only, i.e. having only one curved mirror
    • G02B17/0605—Catoptric systems, e.g. image erecting and reversing system using mirrors only, i.e. having only one curved mirror using two curved mirrors
    • G02B17/061—Catoptric systems, e.g. image erecting and reversing system using mirrors only, i.e. having only one curved mirror using two curved mirrors on-axis systems with at least one of the mirrors having a central aperture
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B17/00—Systems with reflecting surfaces, with or without refracting elements
    • G02B17/02—Catoptric systems, e.g. image erecting and reversing system
    • G02B17/06—Catoptric systems, e.g. image erecting and reversing system using mirrors only, i.e. having only one curved mirror
    • G02B17/0605—Catoptric systems, e.g. image erecting and reversing system using mirrors only, i.e. having only one curved mirror using two curved mirrors
    • G02B17/0621—Catoptric systems, e.g. image erecting and reversing system using mirrors only, i.e. having only one curved mirror using two curved mirrors off-axis or unobscured systems in which not all of the mirrors share a common axis of rotational symmetry, e.g. at least one of the mirrors is warped, tilted or decentered with respect to the other elements
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B17/00—Systems with reflecting surfaces, with or without refracting elements
    • G02B17/02—Catoptric systems, e.g. image erecting and reversing system
    • G02B17/06—Catoptric systems, e.g. image erecting and reversing system using mirrors only, i.e. having only one curved mirror
    • G02B17/0626—Catoptric systems, e.g. image erecting and reversing system using mirrors only, i.e. having only one curved mirror using three curved mirrors
    • G02B17/0631—Catoptric systems, e.g. image erecting and reversing system using mirrors only, i.e. having only one curved mirror using three curved mirrors on-axis systems with at least one of the mirrors having a central aperture

Definitions

  • At least one embodiment of the present disclosure relates to a flat lens and an optical imaging system.
  • the thickness of optical imaging systems such as mobile phones and cameras is largely affected by the thickness of the lens.
  • the design of lenses in optical imaging systems is increasing. The more important.
  • At least one embodiment of the present disclosure provides a flat lens and an optical imaging system.
  • At least one embodiment of the present disclosure provides a flat panel lens, including a first surface and a second surface opposite to each other, the first surface includes an annular light-transmitting area and a first reflective area surrounded by the annular light-transmitting area, The second surface includes an imaging area and a second reflection area surrounding the imaging area.
  • the second reflection area is configured to reflect light incident from the annular light-transmitting area to the first reflection area, and the first reflection area is configured to reflect light incident to the first reflection area To the imaging area;
  • the second reflecting area includes a first reflecting mirror configured to directly reflect light incident on the first reflecting mirror through the annular light-transmitting area to the
  • the first reflecting area, the first reflecting mirror is one of a free-form surface reflecting mirror, an aspherical reflecting mirror, and a spherical reflecting mirror
  • the first reflecting area includes a free-forming surface reflecting mirror, an aspherical reflecting mirror, a spherical reflecting mirror, and a flat surface At least one of the mirrors.
  • the thickness of the flat lens is less than 3 millimeters.
  • the first mirror is a ring mirror
  • the orthographic projection of the ring-shaped light-transmitting area on the second surface completely falls within the first mirror on the second surface. In the orthographic projection on the two sides.
  • the ratio of the maximum dimension of the outer contour of the first mirror to the maximum dimension of the outer contour of the annular light-transmitting area is greater than 1 and less than 1.5.
  • the ratio of the maximum size of the first reflective area to the ring width of the ring-shaped light-transmitting area is greater than 0.5.
  • the sum of the number of plane mirrors and spherical mirrors provided in the first reflection area and the second reflection area is greater than the sum of the numbers of free-form surface mirrors and aspheric mirrors .
  • the maximum field angle of the light incident on the flat lens is 10°.
  • the first reflecting area includes a second reflecting mirror close to the ring-shaped light-transmitting area, and the first reflecting mirror is configured to light incident from the ring-shaped light-transmitting area Reflected to the second mirror.
  • the second reflector is configured to directly reflect light incident on the second reflector to the imaging area, and the second reflector is a flat reflector or a spherical surface. Reflector.
  • the second reflector is configured to directly reflect light incident on the second reflector to the imaging area
  • the first reflector and the second reflector are The mirrors are all aspherical mirrors, and the thickness of the flat lens is not more than 2 millimeters.
  • the second reflection area further includes a third reflection mirror located between the first reflection mirror and the imaging area, and the third reflection mirror surrounds the imaging area
  • the first reflecting area further includes a fourth reflecting mirror located on a side of the second reflecting mirror away from the annular light-transmitting area, and the second reflecting mirror is configured to transmit light incident to the second reflecting mirror Reflected to the third reflecting mirror, the third reflecting mirror is configured to reflect the light incident on the third reflecting mirror to the fourth reflecting mirror.
  • the first reflector and the third reflector are concentric ring structures, and/or, the second reflector and the fourth reflector are concentric structures.
  • the fourth reflector is configured to directly reflect light incident on the fourth reflector to the imaging area, and the second reflector and the third reflector Both the mirror and the fourth mirror are flat mirrors or spherical mirrors.
  • the fourth reflector is configured to directly reflect light incident on the fourth reflector to the imaging area
  • the first reflector and the fourth reflector are
  • the mirror is an aspheric mirror
  • the second mirror is a free-form surface mirror
  • the third mirror is a plane mirror.
  • the thickness of the flat lens is not more than 2 millimeters.
  • the second reflection area further includes a fifth reflection mirror located between the third reflection mirror and the imaging area, and the fifth reflection mirror surrounds the imaging area
  • the first reflecting area further includes a sixth reflecting mirror located on a side of the fourth reflecting mirror away from the annular light-transmitting area, and the fourth reflecting mirror is configured to transmit light incident to the fourth reflecting mirror Reflected to the fifth reflector, the fifth reflector is configured to reflect the light incident on the fifth reflector to the sixth reflector.
  • the sixth reflector is configured to directly reflect light incident on the sixth reflector to the imaging area
  • the second reflector and the third reflector are The mirror, the fourth mirror, the fifth mirror, and the sixth mirror are all flat mirrors or spherical mirrors.
  • Another embodiment of the present disclosure provides an optical imaging system, including: the above-mentioned flat lens and a sensor.
  • the sensor is located in the imaging area of the flat lens, and light incident from the annular light-transmitting area only passes through the reflection of the first reflection area and the second reflection area before entering the sensor.
  • FIG. 1 is a schematic diagram of a cross-sectional structure of a flat lens provided according to an example of an embodiment of the present disclosure
  • FIG. 2 is a schematic plan view of the first surface of the flat lens shown in FIG. 1;
  • FIG. 3 is a schematic plan view of the second surface of the flat lens shown in FIG. 1;
  • FIG. 4 is a schematic diagram of a partial cross-sectional structure of a flat lens provided according to another example of an embodiment of the present disclosure.
  • FIG. 5A is a point diagram of the flat lens shown in FIG. 4;
  • 5B to 5F are enlarged views of the dot sequence shown in FIG. 5A;
  • FIG. 6 is a graph of the transfer function of the flat lens shown in FIG. 4;
  • FIG. 7 is a schematic diagram of a cross-sectional structure of a flat lens provided by another example of an embodiment of the present disclosure.
  • FIG. 8 is a schematic diagram of the planar structure of the first surface of the flat lens shown in FIG. 7;
  • FIG. 9 is a schematic diagram of a planar structure of the second surface of the flat lens shown in FIG. 7;
  • FIG. 10 is a schematic diagram of a partial cross-sectional structure of a flat lens provided according to another example of an embodiment of the present disclosure.
  • FIG. 11A is a spot diagram of the flat lens shown in FIG. 10;
  • 11B to 11E are enlarged views of the dot sequence shown in FIG. 11A;
  • FIG. 12 is a graph of the transfer function of the flat lens shown in FIG. 10;
  • FIG. 13 is a schematic cross-sectional structure diagram of a flat lens provided by another example of an embodiment of the disclosure.
  • FIG. 14 is a schematic diagram of a partial cross-sectional structure of an optical imaging system according to another embodiment of the present disclosure.
  • FIG. 15 is a schematic diagram of a planar structure of an optical imaging system provided according to another example of an embodiment of the present disclosure.
  • mobile phone lenses often adopt a lens structure including multiple lenses.
  • the thickness of each lens in the lens structure affects the thickness of the mobile phone lens, and the lens structure is ultra-thin. It is difficult to improve.
  • the embodiments of the present disclosure provide a flat lens and an optical imaging system.
  • the flat lens includes a first surface and a second surface opposite to each other.
  • the first surface includes a ring-shaped light-transmitting area and a first reflection area surrounded by the ring-shaped light-transmitting area
  • the second surface includes an imaging area and a second reflection area surrounding the imaging area.
  • the second reflection area is configured to reflect light incident from the annular light-transmitting area to the first reflection area
  • the first reflection area is configured to reflect light incident to the first reflection area to the imaging area;
  • the second reflection area includes a first reflection area.
  • the first reflecting mirror is configured to directly reflect the light incident on the first reflecting mirror through the annular light-transmitting area to the first reflecting area, the first reflecting mirror being a free-form surface reflecting mirror, an aspheric reflecting mirror and a spherical reflecting
  • the first reflection area includes at least one of a free-form surface mirror, an aspheric mirror, a spherical mirror, and a flat mirror.
  • the flat lens provided by the embodiments of the present disclosure adopts a reflection system including a first reflection area and a second reflection area, which can not only ensure that no chromatic aberration is generated during the imaging process, but also can reduce the thickness and thickness of the flat lens by setting fewer mirrors. weight.
  • FIG. 1 is a schematic cross-sectional structure diagram of a flat lens provided according to an example of an embodiment of the present disclosure
  • FIG. 2 is a schematic plan view of the first surface of the flat lens shown in FIG. 1
  • FIG. 3 is a second schematic diagram of the flat lens shown in FIG. Schematic plan view of the surface.
  • the flat lens includes a first surface 100 and a second surface 200 opposite to each other.
  • the first surface 100 includes a ring-shaped light-transmitting area 110 and a first reflection area 120 surrounded by the ring-shaped light-transmitting area 110
  • the second surface 200 includes an imaging area 210 and a second reflection area 220 surrounding the imaging area 210.
  • the second reflective area 220 is configured to reflect light incident from the annular light-transmitting area 110 to the first reflective area 120
  • the first reflective area 120 is configured to reflect light from the second reflective area 220 toward the first reflective area 120 Reflected to the imaging area 210.
  • the light incident from the annular light-transmitting area 110 only passes through the reflection of the first reflection area 120 and the second reflection area 220 before entering the imaging area 210.
  • the light incident from the annular light-transmitting area 110 to the flat lens is not transmitted by any lens, but only passes through the first reflection area 120 and the second reflection area 220.
  • the reflection system composed of the reflection system is incident on the imaging area 210.
  • the flat lens provided by the embodiment of the present disclosure can achieve a thinner thickness without considering the thickness of the lens stack, and can also eliminate the chromatic aberration caused by the imaging process.
  • the above "the light incident from the annular light-transmitting area 110 only passes through the reflection of the first reflecting area 120 and the second reflecting area 220 before entering the imaging area 210" means that the light incident from the annular light-transmitting area 110 has not been reflected before entering the imaging area 210.
  • the reflection process may also include the absorption of light by the reflection area.
  • air can be used as the light propagation medium in the above-mentioned light reflection process, which can effectively reduce the production cost of the flat lens.
  • the second reflecting area 220 includes a first reflecting mirror 221 directly opposite to the ring-shaped light-transmitting area 110.
  • the light from the mirror 221 is directly reflected to the first reflection area 120.
  • the first reflector 221 is one of a free-form surface reflector, an aspherical reflector, and a spherical reflector.
  • the first reflector area 120 includes at least one of a free-form surface reflector, an aspherical reflector, a spherical reflector, and a flat reflector.
  • the above-mentioned first reflector and the ring-shaped light-transmitting area are directly opposite to the Y direction shown in FIG.
  • the first reflecting mirror in the embodiments of the present disclosure adopts a free-form surface reflecting mirror, an aspherical reflecting mirror or a spherical reflecting mirror, which can better reflect the light incident from the annular light-transmitting area to the first reflecting area.
  • the first surface 100 and the second surface 200 may both be flat surfaces. But it is not limited to this, and at least one of the first surface and the second surface may also be a curved surface.
  • the first reflecting mirror 221 may be a spherical reflecting mirror to save manufacturing cost.
  • the first mirror 221 may be an aspheric mirror or a free-form surface mirror to better ensure the imaging quality of the flat lens.
  • the thickness of a flat lens is less than 3 mm.
  • the thickness of the flat lens may refer to the average value of the distances between the first surface 100 and the second surface 200.
  • the thickness of a flat-panel lens may refer to the distance between the plane where the imaging area is located and the plane where the ring-shaped light-transmitting area is located.
  • the imaging area of the flat-panel lens in the embodiment of the present disclosure is configured to place a sensor to receive light incident from the annular light-transmitting area and convert the optical signal into an electrical signal.
  • the flat lens in the embodiments of the present disclosure realizes the multi-reflection folding technology through the first reflection area and the second reflection area, which can reduce the thickness of the flat lens while ensuring image quality, and realize a flat lens with a compact optical path structure.
  • the first reflector 221 may be a ring-shaped reflector, and the orthographic projection of the ring-shaped light-transmitting area 110 on the second surface 200 completely falls on the first reflector 221 on the second surface 200.
  • the ratio of the maximum size of the outer contour of the first reflector 221 to the maximum size of the outer contour of the annular light-transmitting region 110 is greater than 1 and less than 1.5.
  • the ring width of the first reflecting mirror 221 is greater than the ring width of the annular light-transmitting area 110, and the first reflecting mirror 221 completely covers the annular light-transmitting area 110, which can ensure that the annular light-transmitting area 110 is incident on the flat lens Among the rays of light at a predetermined angle of view, the rays are basically reflected to the first reflection area 120, which improves the utilization rate of the rays.
  • FIG. 3 schematically shows that the shapes of the ring-shaped light-transmitting area 110 and the first reflector 221 are both circular, but not limited to this, and can also be square ring, or other ring shapes, and the shape of the ring-shaped light-transmitting area
  • the shape of the first reflecting mirror can be the same or different, as long as the orthographic projection of the annular light-transmitting area 110 on the second surface 200 completely falls within the orthographic projection of the first reflecting mirror 221 on the second surface 200.
  • FIG. 3 schematically shows that the imaging area is rectangular, but it is not limited to this, and may also be other regular shapes or irregular shapes such as a circle.
  • FIG. 3 schematically shows that the shape of the first reflector 221 is a closed ring to improve the utilization of light, but it is not limited to this.
  • the shape of the first reflector may be non-uniform. Closed ring.
  • the ratio of the ring width of the annular light-transmitting area 110 to the maximum size of the first reflective area 120 is not greater than 1.
  • the ratio of the maximum size of the first reflective area 120 to the ring width of the ring-shaped light-transmitting area 110 is greater than 0.5.
  • the ratio of the maximum size of the first reflective area to the ring width of the ring-shaped light-transmitting area by designing the ratio of the maximum size of the first reflective area to the ring width of the ring-shaped light-transmitting area, the brightness of the light entering the flat lens and the brightness of the light entering the imaging area can be ensured.
  • the first reflection area 120 may include at least one reflection mirror
  • the second reflection area 220 may include at least one reflection mirror
  • the first reflection area 120 includes a second reflection mirror 121 close to the ring-shaped light-transmitting area 110, and the first reflection mirror 221 is configured to incident light on the ring-shaped light-transmitting area 110. Reflected to the second mirror 121.
  • the embodiment of the present disclosure schematically shows that the orthographic projection of the first mirror 221 on the first surface 100 and the orthographic projection of the second mirror 121 on the first surface 100 overlap.
  • the first reflector and the second reflector overlap to reduce the length or width of the flat lens. But it is not limited to this. In the direction perpendicular to the first surface, the first mirror and the second mirror may not overlap, as long as the light incident from the ring-shaped light-transmitting area can be reflected to the imaging area.
  • the second reflector 121 may be a ring reflector, for example, a closed ring or a non-closed ring, so as to reflect the light reflected by the first reflector 221 to the first reflective surface 120 to the imaging area as much as possible.
  • the embodiments of the present disclosure are not limited to this, and under the condition of ensuring the intensity of the light incident to the imaging area, the second reflector may also have other shapes.
  • the second reflector 121 and the ring-shaped light-transmitting area 110 may be coaxial and ring-shaped to facilitate design and facilitate the propagation of light.
  • the embodiments of the present disclosure are not limited to this.
  • the second reflector may also be a reflector with a circular, square, etc. shape.
  • the second reflector and the annular light-transmitting area may be concentric structures.
  • the embodiments of the present disclosure include but not It is limited to this, as long as the light incident on the second mirror can be reflected to the imaging area.
  • edge of the second reflector 121 and the edge of the annular light-transmitting area 110 may be connected to each other, or may have a certain distance.
  • the second mirror 121 is configured to directly reflect the light incident on the second mirror 121 to the imaging area 210.
  • the orthographic projection of the second mirror 121 on the second surface 200 overlaps with the imaging area 210.
  • a flat lens includes a secondary reflection structure, that is, the second reflection area 220 reflects light only once, for example, it only includes a first reflector, and the first reflection area 120 reflects light only once, for example, it only includes a second reflector.
  • the light incident on the first reflector 221 in the annular light-transmitting area 110 (for example, a clear aperture) is reflected to the second reflector 121, and the second reflector 121 reflects and condenses the light incident on the second reflector 121 to the imaging area. 210.
  • aspheric mirrors and free-form surface mirrors are in the visible light waveband, their cost is hundreds of times that of spherical mirrors, so the cost of manufacturing aspheric mirrors and free-form surface mirrors is relatively high.
  • the design, processing, inspection and adjustment of aspheric mirrors or free-form surface mirrors have gradually matured, so it is feasible to apply aspheric mirrors and free-form surface mirrors in flat lenses.
  • the main problem of using aspheric mirrors and free-form surface mirrors in flat-panel lenses is process issues.
  • the main process issues include the possibility of mass manufacturing, processing, and testing. Imprinting with plastic film can solve the processing problems of general aspheric mirrors and free-form surface mirrors. Therefore, aspheric mirrors and free-form surface mirrors can be used to significantly reduce the thickness of the flat lens.
  • the use of the secondary reflection structure can not only facilitate processing, but also simplify the process of system correction and aberration balance.
  • the second mirror 121 may be a flat mirror or a spherical mirror.
  • flat mirrors or spherical mirrors are used as much as possible, and the use of free-form surface mirrors and aspheric mirrors can be reduced to save costs.
  • FIG. 4 is a schematic partial cross-sectional structure diagram of a flat lens provided according to another example of an embodiment of the present disclosure.
  • the flat lens includes a secondary reflection structure.
  • the first mirror 221 is configured to reflect the light incident on the ring-shaped light-transmitting area 110 to the second mirror 121, and the second mirror 121 is configured to be incident on the The light thereon is directly reflected to the imaging area 210.
  • the second mirror is configured to directly reflect light incident thereon to the imaging area 210" means that the light reflected from the second mirror is incident on the sensor located in the imaging area without passing through other optical elements.
  • the surface of at least one mirror in the second reflective area 220 is provided with a reflective film 201 to make the light incident on the imaging area 210 be light with a predetermined angle of view, so as to prevent light outside the predetermined angle of view from being incident on the imaging area.
  • Light rays of 210, light rays outside the predetermined angle of view incident on the imaging area 210 are regarded as stray light. Stray light is the general term for all abnormally transmitted light in an optical system. The effect of stray light on the performance of the optical system varies from system to system.
  • the reflecting surface of the first reflecting mirror 221 may be provided with a reflecting film 201, and the reflecting film 201 may completely cover the reflecting surface of the first reflecting mirror 221.
  • the reflecting film 201 may completely cover the reflecting surface of the first reflecting mirror 221.
  • it is not limited to this, and it may also cover a part of the reflection surface of the first mirror.
  • the maximum field angle of light incident into the flat lens from the annular light-transmitting area is 10°.
  • the reflective film 201 may be an angular reflective film, and the material of the reflective film 201 may include a metal film layer or a filter layer.
  • the first mirror 221 and the second mirror 121 are both aspherical mirrors, and the thickness of the flat lens is not more than 2 mm.
  • the thickness of the flat lens refers to the average distance between the first surface 100 and the second surface 200.
  • the working wavelength of the flat lens may be 484-656 nm, that is, the wavelength of the light incident on the imaging area 210 includes 484-656 nm.
  • the flat lens in the embodiment of the present disclosure is designed based on the visible light waveband, but it is not limited to this, and it can also be designed only for light in a certain waveband.
  • a rotationally symmetric polynomial aspheric surface is described by adding a polynomial to a spherical surface (or an aspheric surface determined by a quadric surface).
  • the even-order aspheric surface model only uses the even-numbered power of the radial coordinate value to describe the aspheric surface. This mode uses the basic radius of curvature and the quadric coefficient.
  • the aspheric surface coordinates are expressed by the following numerical formula:
  • c is the basic curvature at the center of curvature (that is, the reciprocal of the radius of curvature)
  • k is the conic coefficient (that is, the conic constant)
  • r is the radial coordinate perpendicular to the optical axis
  • 2nth-order aspheric coefficient is in turn an.
  • Table 1 the specific parameters of the optimized design of the flat lens are shown in Table 1.
  • the radius of curvature of the aspheric mirror shown in Table 1 is the radius of curvature of the base spherical surface of the surface.
  • the above-mentioned "base spherical surface” means that the aspheric surface is further deformed and formed on the basis of the spherical surface.
  • the spherical surface as the basis of the aspheric surface is The base spherical surface of the aspheric surface. 4 and the parameters in Table 1, it can be seen that the distance between the first surface of the ring-shaped light-transmitting area 110 and the reflective surface of the first mirror 121 is 0.5834 mm, and the distance between the reflective surface of the first mirror 221 and the second mirror 121 is 0.5834 mm.
  • the distance between the reflective surfaces is 0.402mm, and the distance between the reflective surface of the second mirror 121 and the second surface where the imaging area 210 is located is 0.811mm, so the thickness of the flat lens in the example shown in FIG. 4 can be 2mm .
  • the above-mentioned distance between the reflecting surface and the reflecting surface refers to the distance along the optical axis of the reflecting mirror after being decentered.
  • the distance between the reflecting surface of the above-mentioned reflecting mirror and the first surface or the second surface refers to the distance between the intersection of the reflecting surface and the optical axis and the first surface or the second surface along the optical axis direction.
  • the optical automatic design software will sequentially retrieve the curvature radius, conic coefficient, height, and aspheric coefficient of each mirror in the database and put them into the above numerical formula for calculation to obtain various optimization parameters that can correct the aberration of the mirror.
  • the above-mentioned curvature radius, thickness along the optical axis, aperture, and conic coefficient of each mirror in the flat lens are obtained.
  • the simulated structure of the flat-panel lens constructed after optimization can be obtained that its thickness is not more than 2mm.
  • FIG. 5A is a point sequence diagram of the flat lens shown in FIG. 4, and FIG. 5B to FIG. 5F are enlarged views of the point sequence shown in FIG. 5A.
  • Figures 5A to 5F show the focus of light on the image plane of the imaging area.
  • the spot diagram includes the field angle (DG) of -5°, -3.5°, 0°, 3.5° ,
  • the point sequence at 5° the root mean square (RMS) values of the diameter of the point sequence corresponding to the above five field angles are 0.336 ⁇ m, 0.169 ⁇ m, 0.2 ⁇ m, 0.171 ⁇ m, and 0.283 ⁇ m in order.
  • DG field angle
  • RMS root mean square
  • the radius of the diffuse spot of the flat-panel lens shown in Figure 4 is not greater than 3.5 ⁇ m, and the pixel size of the detector set at the imaging area 210 is not less than 4 ⁇ m, then the root mean square of the diameter of the dot pattern is smaller than the pixel size of the detector. size.
  • Figures 5B to 5F respectively correspond to the point rows when the field of view angles are -5°, -3.5°, 0°, 3.5°, and 5°, and the circle in the figure represents the pixel size of the detector, and the light spot inside the circle For diffuse spots. Therefore, the dot pattern of all the fields of view on the image plane of the imaging area basically falls within the size range of the detector pixels, so the flat-panel lens has a focusing characteristic close to the theoretical limit of diffraction.
  • FIG. 6 is a graph of the transfer function of the flat lens shown in FIG. 4.
  • the figure includes the meridian F1:T, F2:T, F3:T, F4:T, F5:T and sagittal line F1:R, F2:R, F3:R, F4:R, F5:R optical transfer function values at different spatial frequencies, the transfer function curves of each field of view in the figure are close to the diffraction limit , And the contrast at the position where the spatial frequency is 110 line pairs/millimeter (lp/mm) is greater than 0.3, the display image resolution can be 1920*1080, and the image is clear.
  • T Diff.Limit represents the meridian under the diffraction limit
  • R Diff.Limit represents the sagittal line under the diffraction limit, and basically coincides with the meridian F1:T and the sagittal line F1:R at -5°.
  • the first reflecting mirror and the second reflecting mirror are not limited to both aspherical reflecting mirrors, as long as the first reflecting
  • the first reflector can be a spherical reflector
  • the second reflector can be a flat reflector or a spherical reflector to save manufacturing costs.
  • the first reflector can be an aspherical reflector or a free-form surface reflector
  • the second reflector can be a flat reflector or a spherical reflector to better ensure the imaging quality of the flat lens.
  • FIG. 7 is a schematic cross-sectional structure diagram of a flat lens provided by another example of an embodiment of the disclosure.
  • the flat lens includes a first surface 100 and a second surface 200 opposite to each other.
  • the first surface 100 includes a ring-shaped light-transmitting area 110 and a first reflection area 120 surrounded by the ring-shaped light-transmitting area 110
  • the second surface 200 includes an imaging area 210 and a second reflection area 220 surrounding the imaging area 210.
  • the second reflective area 220 is configured to reflect light incident from the annular light-transmitting area 110 to the first reflective area 120
  • the first reflective area 120 is configured to reflect light from the second reflective area 220 toward the first reflective area 120 Reflected to the imaging area 210.
  • the light incident from the ring-shaped light-transmitting area 110 only passes through the reflection of the first reflection area 120 and the second reflection area 220 before entering the imaging area 210, that is, the light that enters the flat lens from the ring-shaped light-transmitting area 110 does not pass through any lens
  • the transmission of is only incident to the imaging area 210 after being reflected by the reflection system composed of the first reflection area 120 and the second reflection area 220, thereby eliminating the chromatic aberration caused by the imaging process.
  • air can be used as the light propagation medium in the above-mentioned light reflection process, which can effectively reduce the production cost of the flat lens.
  • the second reflecting area 220 includes a first reflecting mirror 221 directly opposite to the ring-shaped light-transmitting area 110, and the first reflecting mirror 221 is configured to be incident on the first reflecting mirror through the ring-shaped light-transmitting area 110.
  • the light of 221 is directly reflected to the first reflection area 120.
  • the first reflector 221 is one of a free-form surface reflector, an aspherical reflector, and a spherical reflector.
  • the first reflector area 120 includes at least one of a free-form surface reflector, an aspherical reflector, a spherical reflector, and a flat reflector.
  • the above-mentioned first reflecting mirror and the annular light-transmitting area are directly opposite to the Y direction shown in FIG. 7, and the Y direction may be the direction of the light incident on the annular light-transmitting area.
  • the first reflecting mirror in the embodiment of the present disclosure adopts a free-form surface reflecting mirror, an aspherical reflecting mirror or a spherical reflecting mirror, which can better converge the light incident from the annular light-transmitting area to the first reflecting area.
  • the first surface 100 and the second surface 200 may both be flat surfaces. But it is not limited to this, and at least one of the first surface and the second surface may also be a curved surface.
  • the first reflecting area 120 includes a second reflecting mirror 121 close to the ring-shaped light-transmitting area 110, and the first reflecting mirror 221 is configured to reflect light incident on the ring-shaped light-transmitting area 110 to the second reflecting mirror 121.
  • the second reflecting area 220 further includes a third reflecting mirror 222 located between the first reflecting mirror 221 and the imaging area 210, the third reflecting mirror 222 surrounds the imaging area 210, and the first reflecting area 120 also It includes a fourth reflecting mirror 122 located on the side of the second reflecting mirror 121 away from the annular light-transmitting area 110.
  • the second reflecting mirror 121 is configured to reflect the light incident on the second reflecting mirror 121 to the third reflecting mirror 222.
  • the reflection mirror 222 is configured to reflect the light incident on the third reflection mirror 222 to the fourth reflection mirror 122, and the fourth reflection mirror 122 is configured to directly reflect the light incident on the fourth reflection mirror 122 to the imaging area 210.
  • the first mirror 221, the second mirror 121, the third mirror 222, and the fourth mirror 122 may all be spherical mirrors.
  • the first mirror 221 may be an aspheric mirror or a free-form surface mirror
  • the second mirror 121, the third mirror 222, and the fourth mirror 122 may be flat mirrors or spherical mirrors to better ensure The imaging quality of a flat-panel lens.
  • flat mirrors or spherical mirrors are used as much as possible, and the use of free-form surface mirrors and aspheric mirrors can be reduced to save costs.
  • the sum of the number of flat mirrors and spherical mirrors provided in the first reflection area 120 and the second reflection area 220 is greater than the sum of the numbers of free-form surface mirrors and aspheric mirrors, so as to ensure the imaging quality of the flat lens. On the basis, the production cost can be saved.
  • the thickness of a flat lens is less than 2 mm.
  • the thickness here refers to the average value of the distance between the first surface 100 and the second surface 200.
  • the flat lens in the embodiment of the present disclosure implements the multiple reflection folding technology through the first reflection area and the second reflection area, which can reduce the thickness of the flat lens while ensuring image quality, so that the optical path structure of the flat lens is more compact.
  • FIG. 8 is a schematic diagram of a plan structure of the first surface of the flat lens shown in FIG. 7
  • FIG. 9 is a schematic diagram of a plan structure of the second surface of the flat lens shown in FIG. 7.
  • the first mirror 221 may be a ring-shaped mirror, and the orthographic projection of the ring-shaped light-transmitting area 110 on the second surface 200 completely falls into the orthographic projection of the first mirror 221 on the second surface 200. In the projection, the utilization rate of light is improved.
  • the first mirror 221 and the third mirror 222 may be concentric ring structures spaced apart from each other to better condense the light incident from the ring-shaped light-transmitting area 110 to the imaging area 210.
  • the second mirror 121 and the fourth mirror 122 are concentric structures spaced apart from each other to better converge the light incident from the ring-shaped light-transmitting area 110 to the imaging area 210.
  • FIG. 8 schematically shows that the fourth reflector is ring-shaped, but it is not limited to this, and may also have a structure such as a circle, a square, etc., as long as the light incident on the fourth reflector can be reflected to the imaging area.
  • the embodiments of the present disclosure are not limited to the spacing between the reflecting mirrors located on the same reflecting surface, and the reflecting mirrors located on the same reflecting surface may also be connected to each other.
  • the ratio of the ring width of the annular light-transmitting area 110 to the maximum size of the first reflective area 120 is not greater than 1.
  • the ratio of the maximum size of the first reflective area to the ring width of the ring-shaped light-transmitting area the brightness of the light entering the flat lens and the brightness of the light entering the imaging area can be ensured.
  • the surface of at least one mirror in the second reflection area 220 is provided with a reflection film 201 to reduce the stray light incident on the imaging area 210.
  • the reflecting surface of at least one of the first reflecting mirror 221 and the third reflecting mirror 222 may be provided with a reflecting film, and the reflecting film may completely cover the reflecting surface of the corresponding reflecting mirror. But it is not limited to this, and it can also cover a part of the reflection surface of the corresponding mirror.
  • the reflective film in this example may have the same features as the reflective film in the example shown in FIG. 4, and will not be repeated here.
  • FIG. 10 is a schematic partial cross-sectional structure diagram of a flat lens provided according to another example of an embodiment of the present disclosure.
  • the flat lens includes a quadruple reflection structure.
  • the first mirror 221 is configured to reflect light incident on the ring-shaped light-transmitting area 110 to the second mirror 121, and the second mirror is configured to be incident on it.
  • the light on the upper mirror is reflected to the third mirror 222, the third mirror 222 is configured to reflect the light incident thereon to the fourth mirror 122, and the fourth mirror 122 is configured to be incident on the fourth mirror 122
  • the light is directly reflected to the imaging area 210, the first mirror 221 and the third mirror 222 are an aspheric mirror and a flat mirror, respectively, the second mirror 121 is a free-form surface mirror, and the fourth mirror 122 is a non-spherical mirror. Spherical mirror, and the thickness of the flat lens is not more than 2 mm.
  • the aforementioned "fourth mirror 122 is configured to directly reflect light incident on the fourth mirror 122 to the imaging area 210" means that the light reflected from the fourth mirror is directly incident on the imaging area without passing through other optical structures.
  • the use of the quadruple reflection structure can achieve thinner thickness, such as not more than 1.7 mm, or even less than 1 mm. It can also achieve better imaging effects by optimizing the optical parameters of multiple mirrors, and the optimization process is moderately difficult, so It is suitable for application to higher resolution products.
  • the working wavelength of the flat lens may be 484-656 nm, that is, the wavelength of the light incident on the imaging area 210 includes 484-656 nm.
  • the maximum field of view of a flat lens is 10°.
  • the aspheric surface type is expressed by the following numerical formula:
  • c is the basic curvature at the center of curvature (that is, the reciprocal of the radius of curvature)
  • k is the conic coefficient (that is, the conic constant)
  • r is the radial coordinate perpendicular to the optical axis
  • 2nth-order aspheric coefficient is in turn an.
  • Table 2 the specific parameters of the optimized design of the flat lens are shown in Table 2.
  • the free-form surface is obtained according to the following formula:
  • N is the total number of polynomial coefficients in the series
  • Ai is the coefficient of the i-th extended polynomial.
  • the polynomial is just a power series in the x and y directions.
  • a power series can include x, y, x*x, x*y, and y*y, etc.
  • the highest order term is 20, so that the maximum value of the total number of polynomial aspheric coefficients is 230.
  • the data values at positions such as x and y will be divided by a normalized radius to obtain a dimensionless polynomial coefficient.
  • the distance between the first surface of the ring-shaped light-transmitting area and the reflecting surface of the first mirror is -5.60 mm, and the difference between the reflecting surface of the first reflecting mirror and the reflecting surface of the second reflecting mirror
  • the distance between the two mirrors is 8.320mm
  • the distance between the reflective surface of the second mirror and the reflective surface of the third mirror is -1.04mm
  • the distance between the reflective surface of the third mirror and the reflective surface of the fourth mirror The distance between the reflecting surface of the fourth mirror and the second surface where the imaging area is located is 1.04 mm
  • the thickness of the flat lens in the example shown in FIG. 10 may be 1.598 mm.
  • the distance between the reflecting surface and the reflecting surface may refer to the distance between the reflecting mirrors in the direction of the optical axis after being decentered.
  • the distance between the reflecting surface of the reflecting mirror and the first or second surface means the distance along the optical axis.
  • the negative value of the distance between the first surface and the reflecting surface of the first reflecting mirror means that the distance from the first surface to the reflecting surface is opposite to the direction of light propagation.
  • the first reflecting mirror may have a center of curvature that is not on the optical axis. Eccentric mirror.
  • the optical automatic design software will sequentially retrieve the curvature radius, conic coefficient, height, and aspheric coefficient of each mirror in the database and put them into the above numerical formula for calculation to obtain various optimization parameters that can correct the aberration of the mirror.
  • the above-mentioned curvature radius, thickness along the optical axis, aperture, and conic coefficient of each mirror in the flat lens are obtained.
  • its thickness is, for example, 1.598 mm.
  • FIG. 11A is a point sequence diagram of the flat lens shown in FIG. 10, and FIG. 11B to FIG. 11E are enlarged views of the point sequence shown in FIG. 11A.
  • Figures 11A to 11E show the focus of light on the image plane of the imaging area.
  • the spot diagram includes the sequence of points when the field of view is 1°, -5°, 3.5°, and 0°.
  • the root mean square (RMS) values of the diameter of the dot pattern corresponding to the above four field angles are 1.71 ⁇ m, 1.58 ⁇ m, 3.972 ⁇ m, and 1.183 ⁇ m in order.
  • FIGS. 11B to 11E respectively correspond to the dot rows when the field of view angles are 1°, -5°, 3.5°, and 0°, and the circles in the figure represent the size of the pixels of the detector, and the light spots in the circles are the scattered spots.
  • the dot pattern of all the fields of view on the image plane of the imaging area basically falls within the size range of the detector pixels, so the flat-panel lens has a focusing characteristic close to the theoretical limit of diffraction.
  • Y Diff.Limit represents the meridian under the diffraction limit
  • X Diff.Limit represents the sagittal line under the diffraction limit.
  • FIG. 12 is a graph of the transfer function of the flat lens shown in FIG. 10.
  • the figure includes meridian F1:Y, F2:Y, F3:Y, F4:Y and sagittal line F1 when the field of view angles are 0°, 3.5°, -5°, and 1°:
  • the optical transfer function values of X, F2:X, F3:X, F4:X at different spatial frequencies, the transfer function curves of each field of view in the figure are close to the diffraction limit, and the spatial frequency is 90 line pairs/mm (lp /mm)
  • the contrast at the position is greater than 0.3, and the image is clear.
  • the first reflection zone only includes two mirrors and the second reflection zone only includes two mirrors
  • the first mirror and the fourth mirror are not limited to aspheric mirrors
  • the second mirror is not limited to free-form surface reflection.
  • the third mirror is not limited to the flat mirror, as long as the combination of the first mirror to the fourth mirror can achieve the required imaging effect and is convenient for processing.
  • the structure of the flat lens corresponding to the parameters shown in Table 3 is the same as that of the flat lens shown in Figure 10, but by adjusting the radius of curvature of each mirror, the distance between the mirrors and other parameters, the flat lens shown in Figure 10
  • the thickness is smaller, for example, up to 1 to 2 mm, for example, 0.998 mm.
  • its thickness is, for example, 0.998 mm.
  • the distance between the first surface of the ring-shaped light-transmitting area and the reflecting surface of the first mirror is -1.632 mm, and the reflection of the first reflecting mirror and the second reflecting mirror
  • the distance between the surfaces is 2.277mm
  • the distance between the reflective surface of the second mirror and the reflective surface of the third mirror is -0.126mm
  • between the reflective surface of the third mirror and the reflective surface of the fourth mirror The distance is -0.581mm
  • the distance between the reflective surface of the fourth mirror and the second surface where the imaging area is located is 0.581mm.
  • the spot diagrams of all the fields of view on the image plane of the imaging area basically fall within the size range of the detector pixel, so the flat-panel lens has a focusing characteristic close to the theoretical limit of diffraction.
  • the flat-panel lens has a contrast ratio of more than 0.3 at a spatial frequency of 80 line pairs/millimeter (lp/mm), and the image is clear.
  • the above-mentioned distance between the reflecting surface and the reflecting surface may refer to the distance between the reflecting surface along the direction of the optical axis after being decentered.
  • the distance between the reflecting surface of the above-mentioned reflecting mirror and the first surface or the second surface refers to the distance between the intersection of the reflecting surface and the optical axis and the first surface or the second surface along the optical axis direction. Comparing Table 2 and Table 3, for the quadruple reflection structure, under the premise of ensuring the image quality, the thickness of the flat lens can be further reduced by reducing the radius of curvature of each mirror and optimizing the distance between the reflecting surfaces.
  • FIG. 13 is a schematic cross-sectional structure diagram of a flat lens provided by another example of an embodiment of the disclosure.
  • the flat lens includes a first surface 100 and a second surface 200 opposite to each other.
  • the first surface 100 includes a ring-shaped light-transmitting area 110 and a first reflection area 120 surrounded by the ring-shaped light-transmitting area 110
  • the second surface 200 includes an imaging area 210 and a second reflection area 220 surrounding the imaging area 210.
  • the second reflective area 220 is configured to reflect light incident from the annular light-transmitting area 110 to the first reflective area 120
  • the first reflective area 120 is configured to reflect light from the second reflective area 220 toward the first reflective area 120 Reflected to the imaging area 210.
  • the light incident from the ring-shaped light-transmitting area 110 only passes through the reflection of the first reflection area 120 and the second reflection area 220 before entering the imaging area 210, that is, the light that enters the flat lens from the ring-shaped light-transmitting area 110 does not pass through any lens
  • the transmission of is only reflected by the reflection system composed of the first reflection area 120 and the second reflection area 220 and then incident on the sensor located in the imaging area 210, thereby eliminating the chromatic aberration caused by the imaging process.
  • air can be used as the light propagation medium in the above-mentioned light reflection process, which can effectively reduce the production cost of the flat lens.
  • the second reflecting area 220 includes a first reflecting mirror 221 directly opposite to the ring-shaped light-transmitting area 110, and the first reflecting mirror 221 is configured to be incident on the first reflecting mirror through the ring-shaped light-transmitting area 110.
  • the light of 221 is directly reflected to the first reflection area 120.
  • the first reflector 221 is one of a free-form surface reflector, an aspherical reflector, and a spherical reflector.
  • the first reflector area 120 includes at least one of a free-form surface reflector, an aspherical reflector, a spherical reflector, and a flat reflector.
  • the above-mentioned first reflecting mirror and the annular light-transmitting area are directly opposite to the Y direction shown in FIG. 7, and the Y direction may be the direction of the light incident on the annular light-transmitting area.
  • the first reflecting mirror in the embodiment of the present disclosure adopts a free-form surface reflecting mirror, an aspherical reflecting mirror or a spherical reflecting mirror, which can better converge the light incident from the annular light-transmitting area to the first reflecting area.
  • the first surface 100 and the second surface 200 may both be flat surfaces. But it is not limited to this, and at least one of the first surface and the second surface may also be a curved surface.
  • the first reflection area 120 includes a second reflection mirror 121 close to the ring-shaped light-transmitting area 110, and the first reflection mirror 221 is configured to reflect light incident on the ring-shaped light-transmitting area 110 to the second reflection mirror 121.
  • the second reflection area 220 further includes a third reflection mirror 222 located between the first reflection mirror 221 and the imaging area 210, the third reflection mirror 222 surrounds the imaging area 210, and the first reflection area 120 also It includes a fourth reflecting mirror 122 located on the side of the second reflecting mirror 121 away from the ring-shaped light-transmitting area 110.
  • the second reflecting mirror 121 is configured to reflect the light incident on the second reflecting mirror 121 to the third reflecting mirror 222.
  • the reflecting mirror 222 is configured to reflect the light incident on the third reflecting mirror 222 to the fourth reflecting mirror 122.
  • the second reflecting area 220 further includes a fifth reflecting mirror 223 located between the third reflecting mirror 222 and the imaging area 210, the fifth reflecting mirror 223 surrounds the imaging area 210, and the first reflecting area 120 also It includes a sixth reflector 123 on the side of the fourth reflector 122 away from the ring-shaped light-transmitting area 110.
  • the fourth reflector 122 is configured to reflect the light incident on the fourth reflector 122 to the fifth reflector 223.
  • the reflection mirror 223 is configured to reflect the light incident on the fifth reflection mirror 223 to the sixth reflection mirror 123
  • the sixth reflection mirror 123 is configured to directly reflect the light incident on the sixth reflection mirror 123 to the imaging area 210.
  • the flat lens includes the above-mentioned six reflection structure that reflects the light incident from the ring-shaped light-transmitting area to the imaging area through six reflections.
  • the thickness of the flat-panel lens adopting the six reflection structure can be further reduced, for example, the thickness of the flat-panel lens is less than 1 mm.
  • the first mirror 221, the second mirror 121, the third mirror 222, the fourth mirror 122, the fifth mirror 223, and the sixth mirror 123 may all be spherical mirrors.
  • the first mirror 221 may be an aspheric mirror or a free-form surface mirror
  • the second mirror 121, the third mirror 222, the fourth mirror 122, the fifth mirror 223, and the sixth mirror 123 may be Flat mirror or spherical mirror to better ensure the imaging quality of the flat lens.
  • flat mirrors or spherical mirrors are used as much as possible, and the use of free-form surface mirrors and aspheric mirrors can be reduced to save costs.
  • the sum of the number of flat mirrors and spherical mirrors provided in the first reflection area 120 and the second reflection area 220 is greater than the sum of the numbers of free-form surface mirrors and aspheric mirrors, so as to ensure the imaging quality of the flat lens. On the basis, the production cost can be saved.
  • the thickness of a flat lens is less than 2 mm.
  • the flat lens in the embodiments of the present disclosure realizes the multi-reflection folding technology through the first reflection area and the second reflection area, which can reduce the thickness of the flat lens while ensuring image quality, and realize a flat lens with a compact optical path structure.
  • the first mirror, the third mirror, and the fifth mirror are concentric ring structures spaced apart from each other to better converge the light incident from the ring-shaped light-transmitting area to the imaging area.
  • the second mirror, the fourth mirror, and the sixth mirror are concentric structures spaced apart from each other to better converge the light incident from the ring-shaped light-transmitting area to the imaging area.
  • the sixth mirror may be ring-shaped, but is not limited to this, and may also have a round, square, etc. structure, as long as the light incident on the sixth mirror can be reflected to the imaging area.
  • at least two reflecting mirrors located on the same reflecting surface may be spaced apart, but not limited to this, at least two reflecting mirrors located on the same reflecting surface may also be connected to each other.
  • the ratio of the ring width of the ring-shaped light-transmitting area 110 to the maximum size of the first reflective area 120 is not greater than one.
  • the ratio of the maximum size of the first reflective area to the ring width of the ring-shaped light-transmitting area by designing the ratio of the maximum size of the first reflective area to the ring width of the ring-shaped light-transmitting area, the brightness of the light entering the flat lens and the brightness of the light entering the imaging area can be reduced as much as possible.
  • the thickness of the flat lens is not greater than one.
  • the surface of at least one mirror in the second reflection area is provided with a reflection film to reduce the stray light of the light incident on the imaging area.
  • the reflecting surface of at least one of the first reflecting mirror, the third reflecting mirror and the fifth reflecting mirror may be provided with a reflecting film, and the reflecting film may completely cover the reflecting surface of the corresponding reflecting mirror. But it is not limited to this, and it can also cover a part of the reflection surface of the corresponding mirror.
  • the reflective film in this example may have the same features as the reflective film in the example shown in FIG. 4, and will not be repeated here.
  • At least one of the first surface and the second surface of the flat-panel lens may be an optical plastic substrate.
  • the mirrors on the same surface can be processed by diamond cutting molds, and then processed by injection molding, so as to achieve mass production.
  • Diamond cutting technology can be used to manufacture high-quality infrared optical devices, and can also be used to produce good surface patterns that generate visible light. Therefore, optical systems that require thin, high-quality imaging can be further satisfied by this technology.
  • FIG. 14 is a schematic partial cross-sectional structure diagram of an optical imaging system according to another embodiment of the present disclosure, including the flat lens provided by any of the above examples, and FIG. 14 schematically shows that the flat lens in the optical imaging system is shown in FIG. 10 Flat lens shown.
  • the optical imaging system further includes a sensor 300, which is located in the imaging area of the flat lens.
  • the light incident from the ring-shaped transparent area 110 only passes through the first reflection area and the second reflection area before entering the sensor 300. Reflection. That is, the light incident from the annular light-transmitting area 110 to the flat lens is not transmitted by any lens, but is reflected by the reflection system composed of the first reflection area 120 and the second reflection area 220 and then enters the sensor in the imaging area 210. 300, the thickness of the optical imaging system can be reduced.
  • the sensor 300 completely covers the imaging area so that all light reflected to the imaging area can be received by the sensor 300 to convert the optical signal into an electrical signal.
  • the sensor 300 may include a Charge Coupled Device (CCD) or a Complementary Metal-Oxide-Semiconductor (CMOS).
  • CCD Charge Coupled Device
  • CMOS Complementary Metal-Oxide-Semiconductor
  • the senor 300 can be directly attached to the imaging area of the flat lens without other optical structures such as lenses between the two, so as to further reduce the thickness of the optical imaging system.
  • the sensor can be embedded in a flat lens to further reduce the thickness of the optical imaging system.
  • the optical imaging system provided by the embodiment of the present disclosure may be a device such as a mobile phone or a portable camera.
  • the optical imaging system such as a mobile phone or a camera can be thinner and lighter.
  • FIG. 15 is a schematic diagram of a planar structure of an optical imaging system provided according to another example of an embodiment of the present disclosure.
  • Figure 15 schematically shows the structure of the first surface of the flat panel lens.
  • multiple flat panel lenses can be located on the same substrate. Therefore, the field of view splicing method can be used to view multiple flat panel lenses.
  • Field splicing obtains an optical imaging system such as an ultra-thin light field camera with a large field of view and high resolution.

Landscapes

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

Abstract

一种平板镜头以及光学成像系统，平板镜头包括第一面(100)和第二面(200)，第一面(100)包括环形透光区(110)以及被环形透光区(110)包围的第一反射区(120)，第二面(200)包括成像区(210)以及围绕成像区(210)的第二反射区(220)。第二反射区(220)被配置为将从环形透光区(110)入射的光线反射至第一反射区(120)，第一反射区(120)被配置为将入射至其上的光线反射至成像区(210)；第二反射区(220)包括第一反射镜(221)，第一反射镜(221)为自由曲面反射镜、非球面反射镜以及球面反射镜之一，第一反射区(120)包括自由曲面反射镜、非球面反射镜、球面反射镜以及平面反射镜的至少之一。平板镜头采用包括第一反射区(120)和第二反射区(220)的反射结构，既可以保证在成像过程中不产生色差，还可以减少平板镜头的厚度和重量。

Description

平板镜头以及光学成像系统
本申请要求于2020年6月24日递交的中国专利申请第202010592563.X号的优先权，在此全文引用上述中国专利申请公开的内容以作为本申请的一部分。
技术领域
本公开至少一个实施例涉及一种平板镜头以及光学成像系统。
背景技术
目前，手机、相机等光学成像系统的厚度很大程度上受到镜头的厚度的影响，为了减小手机以及便携式相机的厚度并同时保持相对较好的像质，光学成像系统中的镜头设计越来越重要。
发明内容
本公开的至少一实施例提供一种平板镜头以及光学成像系统。
本公开的至少一实施例提供一种平板镜头，包括彼此相对的第一面和第二面，所述第一面包括环形透光区以及被所述环形透光区包围的第一反射区，所述第二面包括成像区以及围绕所述成像区的第二反射区。所述第二反射区被配置为将从所述环形透光区入射的光线反射至所述第一反射区，所述第一反射区被配置为将入射至所述第一反射区的光线反射至所述成像区；所述第二反射区包括第一反射镜，所述第一反射镜被配置为将通过所述环形透光区入射至所述第一反射镜的光线直接反射至所述第一反射区，所述第一反射镜为自由曲面反射镜、非球面反射镜以及球面反射镜之一，所述第一反射区包括自由曲面反射镜、非球面反射镜、球面反射镜以及平面反射镜的至少之一。
例如，在本公开的实施例中，所述平板镜头的厚度小于3毫米。
例如，在本公开的实施例中，所述第一反射镜为环形反射镜，所述环形透光区在所述第二面上的正投影完全落入所述第一反射镜在所述第二面上的正投影内。
例如，在本公开的实施例中，所述第一反射镜外轮廓最大尺寸与所述环形 透光区的外轮廓的最大尺寸之比大于1且小于1.5。
例如，在本公开的实施例中，所述第一反射区的最大尺寸与所述环形透光区的环宽之比大于0.5。
例如，在本公开的实施例中，所述第一反射区和所述第二反射区设置的平面反射镜和球面反射镜的数量之和大于自由曲面反射镜和非球面反射镜的数量之和。
例如，在本公开的实施例中，入射到所述平板镜头的光线的最大视场角为10°。
例如，在本公开的实施例中，所述第一反射区包括靠近所述环形透光区的第二反射镜，所述第一反射镜被配置为将从所述环形透光区入射的光线反射至所述第二反射镜。
例如，在本公开的实施例中，所述第二反射镜被配置为将入射至所述第二反射镜的光线直接反射至所述成像区，所述第二反射镜为平面反射镜或球面反射镜。
例如，在本公开的实施例中，所述第二反射镜被配置为将入射至所述第二反射镜的光线直接反射至所述成像区，所述第一反射镜和所述第二反射镜均为非球面反射镜，且所述平板镜头的厚度不大于2毫米。
例如，在本公开的实施例中，所述第二反射区还包括位于所述第一反射镜与所述成像区之间的第三反射镜，所述第三反射镜围绕所述成像区，所述第一反射区还包括位于所述第二反射镜远离所述环形透光区一侧的第四反射镜，所述第二反射镜被配置为将入射至所述第二反射镜的光线反射至所述第三反射镜，所述第三反射镜被配置为将入射至所述第三反射镜的光线反射至所述第四反射镜。
例如，在本公开的实施例中，所述第一反射镜和所述第三反射镜为同心环结构，和/或，所述第二反射镜与所述第四反射镜为同心结构。
例如，在本公开的实施例中，所述第四反射镜被配置为将入射至所述第四反射镜的光线直接反射至所述成像区，所述第二反射镜、所述第三反射镜以及所述第四反射镜均为平面反射镜或球面反射镜。
例如，在本公开的实施例中，所述第四反射镜被配置为将入射至所述第四反射镜的光线直接反射至所述成像区，所述第一反射镜和所述第四反射镜为非球面反射镜，所述第二反射镜为自由曲面反射镜，且所述第三反射镜为平面反 射镜。
例如，在本公开的实施例中，所述平板镜头的厚度不大于2毫米。
例如，在本公开的实施例中，所述第二反射区还包括位于所述第三反射镜与所述成像区之间的第五反射镜，所述第五反射镜围绕所述成像区，所述第一反射区还包括位于所述第四反射镜远离所述环形透光区一侧的第六反射镜，所述第四反射镜被配置为将入射至所述第四反射镜的光线反射至所述第五反射镜，所述第五反射镜被配置为将入射至所述第五反射镜的光线反射至所述第六反射镜。
例如，在本公开的实施例中，所述第六反射镜被配置为将入射至所述第六反射镜的光线直接反射至所述成像区，所述第二反射镜、所述第三反射镜、所述第四反射镜、所述第五反射镜以及所述第六反射镜均为平面反射镜或球面反射镜。
本公开的另一实施例提供一种光学成像系统，包括：上述平板镜头以及传感器。所述传感器位于所述平板镜头的所述成像区，从所述环形透光区入射的光线在进入所述传感器之前仅经过所述第一反射区和所述第二反射区的反射。
附图说明
为了更清楚地说明本公开实施例的技术方案，下面将对实施例的附图作简单地介绍，显而易见地，下面描述中的附图仅仅涉及本公开的一些实施例，而非对本公开的限制。
图1为根据本公开实施例的一示例提供的平板镜头的截面结构示意图；
图2为图1所示的平板镜头的第一面的平面示意图；
图3为图1所示平板镜头的第二面的平面示意图；
图4为根据本公开一实施例的另一示例提供的平板镜头的局部截面结构示意图；
图5A为图4所示的平板镜头的点列图；
图5B至图5F为图5A所示点列放大图；
图6为图4所示的平板镜头的传递函数曲线图；
图7为本公开实施例的另一示例提供的平板镜头的截面结构示意；
图8为图7所示平板镜头的第一面的平面结构示意图；
图9为图7所示平板镜头的第二面的平面结构示意图；
图10为根据本公开一实施例的另一示例提供的平板镜头的局部截面结构示意图；
图11A为图10所示的平板镜头的点列图；
图11B至图11E为图11A所示点列放大图；
图12为图10所示的平板镜头的传递函数曲线图；
图13为本公开实施例的另一示例提供的平板镜头的截面结构示意图；
图14为根据本公开另一实施例提供的一种光学成像系统的局部剖面结构示意图；以及
图15为根据本公开实施例的另一示例提供的光学成像系统的平面结构示意图。
具体实施方式
为使本公开实施例的目的、技术方案和优点更加清楚，下面将结合本公开实施例的附图，对本公开实施例的技术方案进行清楚、完整地描述。显然，所描述的实施例是本公开的一部分实施例，而不是全部的实施例。基于所描述的本公开的实施例，本领域普通技术人员在无需创造性劳动的前提下所获得的所有其它实施例，都属于本公开保护的范围。
除非另外定义，本公开使用的技术术语或者科学术语应当为本公开所属领域内具有一般技能的人士所理解的通常意义。本公开中使用的“第一”、“第二”以及类似的词语并不表示任何顺序、数量或者重要性，而只是用来区分不同的组成部分。“包括”或者“包含”等类似的词语意指出现该词前面的元件或者物件涵盖出现在该词后面列举的元件或者物件及其等同，而不排除其他元件或者物件。
在研究中，本申请的发明人发现：手机镜头常常采用包括多个透镜的透镜式结构，该透镜式结构中各透镜的厚度会影响手机镜头的厚度，且对该透镜式结构进行超薄化改进具有一定难度。
本公开的实施例提供一种平板镜头以及光学成像系统。平板镜头包括彼此相对的第一面和第二面，第一面包括环形透光区以及被环形透光区包围的第一反射区，第二面包括成像区以及围绕成像区的第二反射区。第二反射区被配置为将从环形透光区入射的光线反射至第一反射区，第一反射区被配置为将入射至第一反射区的光线反射至成像区；第二反射区包括第一反射镜，第一反射镜 被配置为将通过环形透光区入射至第一反射镜的光线直接反射至第一反射区，第一反射镜为自由曲面反射镜、非球面反射镜以及球面反射镜之一，第一反射区包括自由曲面反射镜、非球面反射镜、球面反射镜以及平面反射镜的至少之一。本公开实施例提供的平板镜头采用包括第一反射区和第二反射区的反射系统，既可以保证在成像过程中不产生色差，还可以通过设置较少的反射镜以减少平板镜头的厚度和重量。
下面结合附图对本公开实施例提供的平板镜头以及光学成像系统进行描述。
图1为根据本公开实施例的一示例提供的平板镜头的截面结构示意图，图2为图1所示的平板镜头的第一面的平面示意图，图3为图1所示平板镜头的第二面的平面示意图。如图1至图3所示，平板镜头包括彼此相对的第一面100和第二面200。第一面100包括环形透光区110以及被环形透光区110包围的第一反射区120，第二面200包括成像区210以及围绕成像区210的第二反射区220。第二反射区220被配置为将从环形透光区110入射的光线反射至第一反射区120，第一反射区120被配置为将从第二反射区220射向第一反射区120的光线反射至成像区210。从环形透光区110入射的光线在进入成像区210之前仅经过第一反射区120和第二反射区220的反射。相对于采用透镜的镜头，本公开实施例提供的平板镜头中，从环形透光区110入射到平板镜头的光线没有经过任何透镜的透射，仅是经过第一反射区120和第二反射区220组成的反射系统的反射后入射至成像区210，由此，本公开实施例提供的平板镜头既可以无需考虑透镜叠加的厚度而实现较薄厚度，还可以消除成像过程产生的色差。上述“从环形透光区110入射的光线在进入成像区210之前仅经过第一反射区120和第二反射区220的反射”指从环形透光区110入射的光线在进入成像区210之前没有经过任何透镜的透射，该反射过程中也可以包括反射区对光线的吸收。例如，上述光线的反射过程中可以采用空气作为光线传播介质，能够有效降低平板镜头的生产成本。
如图1至图3所示，第二反射区220包括与环形透光区110正对的第一反射镜221，第一反射镜221被配置为将通过环形透光区110入射至第一反射镜221的光线直接反射至第一反射区120。第一反射镜221为自由曲面反射镜、非球面反射镜以及球面反射镜之一，第一反射区120包括自由曲面反射镜、非球面反射镜、球面反射镜以及平面反射镜的至少之一。上述第一反射镜与环形 透光区在图1所示的Y方向正对，例如Y方向可以为入射到环形透光区的光线的传播方向。本公开实施例中的第一反射镜采用自由曲面反射镜、非球面反射镜或者球面反射镜，可以将从环形透光区入射的光更好的反射至第一反射区。
例如，如图1至图3所示，第一面100和第二面200可以均为平面。但不限于此，第一面和第二面的至少之一也可以为曲面。
例如，第一反射镜221可以为球面反射镜，以节约制作成本。
例如，第一反射镜221可以为非球面反射镜或者自由曲面反射镜以更好的保证平板镜头的成像质量。
例如，平板镜头的厚度小于3毫米。例如，平板镜头的厚度可以指第一面100与第二面200之间的各位置的距离的平均值。例如，平板镜头的厚度可以指成像区所在平面与环形透光区所在平面之间的距离。本公开实施例中平板镜头的成像区被配置为放置传感器以接收从环形透光区入射的光线，并将光信号转换为电信号。本公开实施例中的平板镜头通过第一反射区和第二反射区实现多次反射折叠技术，可以在保证像质的同时，减小平板镜头的厚度，实现光路结构紧凑的平板镜头。
例如，如图1至图3所示，第一反射镜221可以为环形反射镜，环形透光区110在第二面200上的正投影完全落入第一反射镜221在第二面200上的正投影内。例如，第一反射镜221的外轮廓最大尺寸与环形透光区110的外轮廓的最大尺寸之比大于1且小于1.5。例如，沿X方向，第一反射镜221的环宽大于环形透光区110的环宽，且第一反射镜221完全覆盖环形透光区110，可以保证由环形透光区110入射至平板镜头的光线中处于预定视场角的光线基本反射至第一反射区120，提高光线的利用率。
例如，图3示意性的示出环形透光区110和第一反射镜221的形状均为圆环形，但不限于此，还可以为方环形，或者其他环形形状，环形透光区的形状与第一反射镜的形状可以相同，也可以不同，只要环形透光区110在第二面200上的正投影完全落入第一反射镜221在第二面200上的正投影内即可。图3示意性的示出成像区为矩形，但不限于此，还可以是圆形等其他规则形状或不规则形状。
例如，图3示意性的示出第一反射镜221的形状为封闭的环形以提高光线的利用率，但不限于此，在保证入射光线亮度的情况下，第一反射镜的形状可 以为非封闭的环形。
例如，如图2所示，环形透光区110的环宽与第一反射区120的最大尺寸之比不大于1。例如，第一反射区120的最大尺寸与环形透光区110的环宽之比大于0.5。本公开实施例中通过对第一反射区的最大尺寸与环形透光区的环宽之比的设计，可以保证进入平板镜头的光线亮度以及入射至成像区的光线亮度。
例如，如图1至图3所示，第一反射区120可以包括至少一个反射镜，第二反射区220可以包括至少一个反射镜。
例如，如图1至图3所示，第一反射区120包括靠近环形透光区110的第二反射镜121，第一反射镜221被配置为将环形透光区110入射至其上的光反射至第二反射镜121。例如，本公开实施例示意性的示出第一反射镜221在第一面100上的正投影与第二反射镜121在第一面100上的正投影有交叠。本公开实施例中，以第一面为平面为例，则沿垂直于第一面的方向，第一反射镜与第二反射镜有交叠可以减小平板镜头的长度或者宽度。但不限于此，沿垂直于第一面的方向，第一反射镜与第二反射镜也可以没有交叠，只要可以将从环形透光区入射的光反射至成像区即可。
例如，第二反射镜121可以为环形反射镜，例如，封闭的环形或者非封闭的环形，以将第一反射镜221反射至第一反射面120的光尽可能多的反射至成像区。本公开实施例不限于此，在保证入射至成像区的光线强度的条件下，第二反射镜也可以为其他形状。
例如，第二反射镜121与环形透光区110可以为同轴环形，以方便设计，有利于光线的传播。本公开实施例不限于此，例如，第二反射镜也可以为圆形、方形等形状的反射镜，此时第二反射镜与环形透光区可以为同心结构，本公开实施例包括但不限于此，只要可以将入射至第二反射镜的光线反射至成像区即可。
例如，第二反射镜121的边缘与环形透光区110的边缘可以相接，也可以具有一定的距离。
例如，如图1至图3所示，第二反射镜121被配置为将入射至第二反射镜121的光线直接反射至成像区210。例如，第二反射镜121在第二面200上的正投影与成像区210有交叠。例如，平板镜头包括二次反射结构，即第二反射区220仅反射一次光线，例如仅包括一个第一反射镜，第一反射区120仅反射 一次光线，例如仅包括一个第二反射镜，从环形透光区110(例如通光孔径)入射至第一反射镜221的光线被反射至第二反射镜121，第二反射镜121将入射至第二反射镜121的光线再次反射会聚至成像区210。
例如，在设计平板镜头中的反射镜时，需合理采用非球面反射镜或者自由曲面反射镜来有效地校正和平衡像差，使得成像质量满足要求。由于非球面反射镜和自由曲面反射镜在可见光波段内，其造价是球面反射镜的成百倍，由此非球面反射镜和自由曲面反射镜的制作成本较高。目前，非球面反射镜或自由曲面反射镜的设计、加工、检验以及装调已经逐渐成熟，所以平板镜头中应用非球面反射镜和自由曲面反射镜是可行的。平板镜头中采用非球面反射镜和自由曲面反射镜的问题主要是工艺问题，主要的工艺问题包括批量制造的可能性、加工以及检测。而用塑料薄膜压印可解决一般非球面反射镜和自由曲面反射镜的加工问题，由此，可以采用非球面反射镜和自由曲面反射镜使平板镜头的厚度明显变薄。采用二次反射结构既可以方便加工，也可以简化系统校正和平衡像差的过程。
例如，如图1所示，第二反射镜121可以为平面反射镜或球面反射镜。本公开实施例中，在保证成像质量的前提下，尽量使用平面反射镜或球面反射镜，减少自由曲面反射镜和非球面反射镜的使用可以节约成本。
例如，图4为根据本公开一实施例的另一示例提供的平板镜头的局部截面结构示意图。如图4所示，平板镜头包括二次反射结构，第一反射镜221被配置为将环形透光区110入射的光线反射至第二反射镜121，第二反射镜121被配置为将入射至其上的光线直接反射至成像区210。这里的“第二反射镜被配置为将入射至其上的光线直接反射至成像区210”指从第二反射镜反射的光没有经过其他光学元件就入射至位于成像区的传感器中。
例如，第二反射区220中的至少一个反射镜的表面设有反射膜201以使入射到成像区210的光线为预定视场角的光线，以防止预定视场角以外的光线入射到成像区210的光线，以预定视场角以外的光线入射到成像区210的光线视为杂散光。杂散光(Stray light)是光学系统中所有非正常传输光的总称，杂散光对光学系统性能的影响因系统不同而变化。
例如，第一反射镜221的反射面可以设置反射膜201，反射膜201可以完全覆盖第一反射镜221的反射面。但不限于此，也可以覆盖第一反射镜的部分反射面。本公开实施例中，通过在第一反射镜221设置反射膜201，可以使得 某一角度范围内的光线在各反射区反射，以使进入成像区210的光线基本为以预定视场角进入成像区210的光线。
例如，从环形透光区入射到平板镜头内的光线的最大视场角为10°。
例如，反射膜201可以为角度反射膜，反射膜201的材料可以包括金属膜层或者过滤层等。
例如，如图4所示，本公开实施例的一示例中，第一反射镜221和第二反射镜121均为非球面反射镜，且平板镜头的厚度不大于2毫米。平板镜头的厚度指第一面100与第二面200之间的平均距离。
例如，平板镜头的工作波段可以为484～656nm，即入射到成像区210的光线的波段包括484～656nm。例如，本公开实施例中的平板镜头基于可见光波段进行设计，但不限于此，也可以仅针对某一波段的光进行设计。
例如，旋转对称的多项式非球面是通过在一个球面(或是用二次曲面确定的非球面)上加上一个多项式来描述。偶次非球面模型仅用径向坐标值的偶数次幂来描述非球面。这个模式使用基本曲率半径和二次曲面系数。非球面面型坐标用下列数值公式表示：
Figure PCTCN2021094758-appb-000001
上述公式中的c为曲率中心处的基本曲率(即曲率半径的倒数)，k为圆锥系数(即圆锥曲线常数)，r为垂直光轴方向的径向坐标，第2n阶非球面系数依次是an。本示例中，优化设计得到的平板镜头的具体参数如表1所示。
表1
  曲率半径/mm 间距/mm 光学材料 圆锥系数
物面 无限 无限 - -
环形透光区 无限 0.5834 - -
第一反射镜 -12.502 0.402 反射材料 3.202
第二反射镜 2.1903 0.811 反射材料 -12.082
成像区 无限 0 - -
表1所示的非球面反射镜的曲率半径为其表面的基球面的曲率半径，上述的“基球面”指非球面是以球面为基础进一步变形形成的，作为该非球面基础的球面即为该非球面的基球面。参考图4以及表1参数可知，环形透光区110所在第一面与第一反射镜121的反射面之间的距离为0.5834mm，第一反射镜221的反射面与第二反射镜121的反射面之间的距离为0.402mm，第二反射镜121的反射面与成像区210所在的第二面之间的距离为0.811mm，则图4所示示例 中的平板镜头的厚度可以为2mm。上述反射面与反射面之间的距离是指反射镜经偏心后沿光轴方向的距离。上述反射镜的反射面与第一面或第二面的距离指沿光轴方向，反射面与光轴的交点距第一面或第二面的距离。
光学自动设计软件会在数据库中依次调取各反射镜的曲率半径、圆锥系数、高度以及非球面系数等值放入上述数值公式中进行计算以得到能够校正反射镜的像差的各个优化参数。通过优化过程得到平板镜头中各个反射镜的上述曲率半径、沿光轴的厚度、口径以及圆锥系数的优选值。通过优化后构建的平板镜头的模拟结构中可以得到其厚度不大于2mm。
例如，图5A为图4所示的平板镜头的点列图，图5B至图5F为图5A所示点列的放大图。图5A至图5F示出了光线在成像区的像面的聚焦情况，如图5A所示，点列图包括视场角(DG)依次为-5°、-3.5°、0°、3.5°、以及5°时的点列，上述五个视场角对应的点列图直径的均方根(RMS)值依次为0.336μm、0.169μm、0.2μm、0.171μm以及0.283μm。例如，图4所示平板镜头的弥散斑的半径不大于3.5μm，成像区210位置处设置的探测器的像素的尺寸不小于4μm，则点列图直径的均方根小于探测器的像素的尺寸。图5B至图5F分别对应于视场角依次为-5°、-3.5°、0°、3.5°、以及5°时的点列，且图中圆圈表示探测器的像素的尺寸，圆圈内光斑为弥散斑。由此，成像区的像面上所有视场的点列图基本落在探测器像素的尺寸范围内，由此该平板镜头具有接近于衍射理论极限的聚焦特性。
例如，图6为图4所示的平板镜头的传递函数曲线图。如图6所示，图中包括视场角依次为-5°、-3.5°、0°、3.5°、以及5°时的子午线F1:T、F2:T、F3:T、F4:T、F5:T和弧矢线F1:R、F2:R、F3:R、F4:R、F5:R在不同空间频率下的光学传递函数数值，图中各视场的传递函数曲线都接近衍射极限，且在空间频率为110线对/毫米(lp/mm)位置处的对比度大于0.3，则显示图像分辨率可以为1920*1080，且成像清晰。图中的T Diff.Limit表示衍射极限下的子午线，R Diff.Limit表示衍射极限下的弧矢线，且分别与-5°时的子午线F1:T和弧矢线F1:R基本重合。
当然，在第一反射区仅包括一个第二反射镜，第二反射区仅包括一个第一反射镜时，第一反射镜和第二反射镜不限于均为非球面反射镜，只要第一反射镜和第二反射镜的组合能达到需要的成像效果并且便于加工即可。例如，第一反射镜可以为球面反射镜，第二反射镜可以为平面反射镜或球面反射镜以节约 制作成本。例如，第一反射镜可以为非球面反射镜或者自由曲面反射镜，第二反射镜可以为平面反射镜或球面反射镜以更好的保证平板镜头的成像质量。
例如，图7为本公开实施例的另一示例提供的平板镜头的截面结构示意图。如图7所示，平板镜头包括彼此相对的第一面100和第二面200。第一面100包括环形透光区110以及被环形透光区110包围的第一反射区120，第二面200包括成像区210以及围绕成像区210的第二反射区220。第二反射区220被配置为将从环形透光区110入射的光线反射至第一反射区120，第一反射区120被配置为将从第二反射区220射向第一反射区120的光线反射至成像区210。从环形透光区110入射的光线在进入成像区210之前仅经过第一反射区120和第二反射区220的反射，也就是，从环形透光区110入射到平板镜头的光线没有经过任何透镜的透射，仅是经过第一反射区120和第二反射区220组成的反射系统的反射后入射至成像区210，由此，可以消除成像过程产生的色差。例如，上述光线的反射过程中可以采用空气作为光线传播介质，能够有效降低平板镜头的生产成本。
例如，如图7所示，第二反射区220包括与环形透光区110正对的第一反射镜221，第一反射镜221被配置为将通过环形透光区110入射至第一反射镜221的光线直接反射至第一反射区120。第一反射镜221为自由曲面反射镜、非球面反射镜以及球面反射镜之一，第一反射区120包括自由曲面反射镜、非球面反射镜、球面反射镜以及平面反射镜的至少之一。上述第一反射镜与环形透光区在图7所示的Y方向正对，Y方向可以为入射到环形透光区的光线的方向。本公开实施例中的第一反射镜采用自由曲面反射镜、非球面反射镜或者球面反射镜，可以将从环形透光区入射的光更好的会聚至第一反射区。
例如，如图7所示，第一面100和第二面200可以均为平面。但不限于此，第一面和第二面的至少之一也可以为曲面。
例如，第一反射区120包括靠近环形透光区110的第二反射镜121，第一反射镜221被配置为将环形透光区110入射至其上的光反射至第二反射镜121。例如，如图7所示，第二反射区220还包括位于第一反射镜221与成像区210之间的第三反射镜222，第三反射镜222围绕成像区210，第一反射区120还包括位于第二反射镜121远离环形透光区110一侧的第四反射镜122，第二反射镜121被配置为将入射至第二反射镜121的光线反射至第三反射镜222，第三反射镜222被配置为将入射至第三反射镜222的光线反射至第四反射镜122， 第四反射镜122被配置为将入射至第四反射镜122的光线直接反射至成像区210。
例如，第一反射镜221、第二反射镜121、第三反射镜222以及第四反射镜122均可以为球面反射镜。例如，第一反射镜221可以为非球面反射镜或者自由曲面反射镜，第二反射镜121、第三反射镜222以及第四反射镜122可以为平面反射镜或球面反射镜以更好的保证平板镜头的成像质量。本公开实施例中，在保证成像质量的前提下，尽量使用平面反射镜或球面反射镜，减少自由曲面反射镜和非球面反射镜的使用可以节约成本。
例如，第一反射区120和第二反射区220设置的平面反射镜和球面反射镜的数量之和大于自由曲面反射镜和非球面反射镜的数量之和，以在保证平板镜头的成像质量的基础上，可以节约制作成本。
例如，平板镜头的厚度小于2毫米。这里的厚度指第一面100和第二面200之间的距离的平均值。本公开实施例中的平板镜头通过第一反射区和第二反射区实现多次反射折叠技术，可以在保证像质的同时，减小平板镜头的厚度，以使平板镜头的光路结构更紧凑。
例如，图8为图7所示平板镜头的第一面的平面结构示意图，图9为图7所示平板镜头的第二面的平面结构示意图。如图7至图9所示，第一反射镜221可以为环形反射镜，环形透光区110在第二面200上的正投影完全落入第一反射镜221在第二面200上的正投影内，提高光线的利用率。
例如，第一反射镜221和第三反射镜222可以为彼此间隔的同心环结构以将从环形透光区110入射的光更好的会聚到成像区210。例如，第二反射镜121与第四反射镜122为彼此间隔的同心结构以将从环形透光区110入射的光更好的会聚到成像区210。图8示意性的示出第四反射镜为环状，但不限于此，还可以为圆形、方形等结构，只要可以将入射至第四反射镜的光线反射至成像区即可。本公开实施例不限于位于同一反射面的反射镜之间设有间隔，位于同一反射面的反射镜还可以彼此相接。
例如，如图7所示，环形透光区110的环宽与第一反射区120的最大尺寸之比不大于1。本公开实施例中通过对第一反射区的最大尺寸与环形透光区的环宽之比的设计，可以保证进入平板镜头的光线亮度以及入射至成像区的光线亮度。
例如，第二反射区220中的至少一个反射镜的表面设有反射膜201以减少 入射到成像区210的杂散光。例如，第一反射镜221和第三反射镜222的至少一个的反射面可以设置反射膜，反射膜可以完全覆盖相应反射镜的反射面。但不限于此，也可以覆盖相应反射镜的部分反射面。本示例中的反射膜可以与图4所示示例中的反射膜具有相同的特征，在此不再赘述。
例如，图10为根据本公开一实施例的另一示例提供的平板镜头的局部截面结构示意图。如图10所示，平板镜头包括四次反射结构，第一反射镜221被配置为将环形透光区110入射的光线反射至第二反射镜121，第二反射镜被配置为将入射至其上的光线反射至第三反射镜222，第三反射镜222被配置为将入射至其上的光线反射至第四反射镜122，第四反射镜122被配置为将入射至第四反射镜122的光线直接反射至成像区210，第一反射镜221和第三反射镜222分别为非球面反射镜和平面反射镜，第二反射镜121为自由曲面反射镜，且第四反射镜122为非球面反射镜，且平板镜头的厚度不大于2毫米。上述的“第四反射镜122被配置为将入射至第四反射镜122的光线直接反射至成像区210”指从第四反射镜反射的光线没有经过其他光学结构而直接入射至位于成像区的传感器中。采用四次反射结构既可以实现更薄的厚度，例如不大于1.7毫米，甚至小于1毫米，还可以通过优化多个反射镜的光学参数实现更好的成像效果，且优化过程的难度适中，从而适宜于应用到更高分辨率的产品中。
例如，平板镜头的工作波段可以为484～656nm，即入射到成像区210的光线的波段包括484～656nm。例如，平板镜头的最大视场角为10°。
例如，非球面面型用下列数值公式表示：
Figure PCTCN2021094758-appb-000002
上述公式中的c为曲率中心处的基本曲率(即曲率半径的倒数)，k为圆锥系数(即圆锥曲线常数)，r为垂直光轴方向的径向坐标，第2n阶非球面系数依次是an。本示例中，优化设计得到的平板镜头的具体参数如表2所示。
所述自由曲面按照下式得到：
Figure PCTCN2021094758-appb-000003
上述公式中，N为级数中多项式系数的总数，Ai为第i项扩展多项式的系数。该多项式只是在x方向和y方向的幂级数。例如，幂级数可以依次包括x、y、x*x、x*y以及y*y等，上述幂级数中的1次项有2项，2次项有3项，3次项有4项等，最高次项为20，以使得多项式非球面系数总数的最大值为230。 x和y等位置的数据值都会除以一个归一化半径，得到一个没有量纲的多项式系数。
表2
  曲率半径/mm 间距/mm 光学材料 圆锥系数
物面 无限 无限 - -
环形透光区 无限 -5.60 - -
第一反射镜 -25.951 8.320 反射材料 2.013
第二反射镜 15.612 -1.04 反射材料 -1.1132
第三反射镜 无限 -1.04 反射材料 0
第四反射镜 15.4243 1.04 反射材料 -6.5
成像区 无限 0 - -
参考图10以及表2参数可知，环形透光区所在第一面与第一反射镜的反射面之间的距离为-5.60mm，第一反射镜的反射面与第二反射镜的反射面之间的距离为8.320mm，第二反射镜的反射面与第三反射镜的反射面之间的距离为-1.04mm，第三反射镜的反射面与第四反射镜的反射面之间的距离为-1.04mm，第四反射镜的反射面与成像区所在的第二面之间的距离为1.04mm，则图10所示示例中的平板镜头的厚度可以为1.598mm。上述反射面与反射面之间的距离可以指反射镜之间经偏心后沿光轴方向的距离，上述反射镜的反射面与第一面或第二面的距离指沿光轴方向，反射面距第一面或第二面的距离。上述第一面与第一反射镜的反射面之间的距离为负值表示第一面到反射面的距离与光的传播方向相反，例如，第一反射镜可以为曲率中心不位于光轴上的偏心反射镜。
光学自动设计软件会在数据库中依次调取各反射镜的曲率半径、圆锥系数、高度以及非球面系数等值放入上述数值公式中进行计算以得到能够校正反射镜的像差的各个优化参数。通过优化过程得到平板镜头中各个反射镜的上述曲率半径、沿光轴的厚度、口径以及圆锥系数的优选值。通过优化后构建的平板镜头的模拟结构中可以得到其厚度例如为1.598mm。
例如，图11A为图10所示的平板镜头的点列图，图11B至图11E为图11A所示点列的放大图。图11A至图11E示出了光线在成像区的像面的聚焦情况，如图5A所示，点列图包括视场角依次为1°、-5°、3.5°以及0°时的点列，上述四个视场角对应的点列图直径的均方根(RMS)值依次为1.71μm、1.58μm、3.972μm以及1.183μm。例如，图11A所示平板镜头的弥散斑的半径不大于3.5μm，成像区210位置处设置的探测器的像素的尺寸不小于4μm，则点列图 直径的均方根小于探测器的像素的尺寸。图11B至图11E分别对应于视场角依次为1°、-5°、3.5°以及0°时的点列，且图中圆圈表示探测器的像素的尺寸，圆圈内光斑为弥散斑。由此，成像区的像面上所有视场的点列图基本落在探测器像素的尺寸范围内，由此该平板镜头具有接近于衍射理论极限的聚焦特性。图中的Y Diff.Limit表示衍射极限下的子午线，X Diff.Limit表示衍射极限下的弧矢线。
例如，图12为图10所示的平板镜头的传递函数曲线图。如图12所示，图中包括视场角依次为0°、3.5°、-5°以及1°时的子午线F1:Y、F2:Y、F3:Y、F4:Y和弧矢线F1:X、F2:X、F3:X、F4:X在不同空间频率下的光学传递函数数值，图中各视场的传递函数曲线都接近衍射极限，且在空间频率为90线对/毫米(lp/mm)位置处的对比度大于0.3，成像清晰。
当然，在第一反射区仅包括两个反射镜，第二反射区仅两个反射镜时，第一反射镜和第四反射镜不限于非球面反射镜，第二反射镜不限于自由曲面反射镜，且第三反射镜也不限于平面反射镜，只要第一反射镜至第四反射镜的组合能达到需要的成像效果并且便于加工即可。
表3
  曲率半径/mm 间距/mm 光学材料 圆锥系数
物面 无限 无限 - -
环形透光区 无限 -1.632 - -
第一反射镜 -11.308 2.277 反射材料 2.013
第二反射镜 4.626 -0.126 反射材料 -1.1132
第三反射镜 无限 -0.581 反射材料 0
第四反射镜 6.085 0.581 反射材料 -6.5
成像区 无限 0 - -
表3所示参数对应的平板镜头的结构与图10所示的平板镜头的结构相同，但通过调整各反射镜的曲率半径、反射镜之间的距离等参数，可以使得图10所示平板镜头的厚度更小，例如达到1～2mm，例如为0.998mm。通过优化后构建的平板镜头的模拟结构中可以得到其厚度例如为0.998mm。
例如，参考图10以及表3参数可知，环形透光区所在第一面与第一反射镜的反射面之间的距离为-1.632mm，第一反射镜的反射面与第二反射镜的反射面之间的距离为2.277mm，第二反射镜的反射面与第三反射镜的反射面之间的距离为-0.126mm，第三反射镜的反射面与第四反射镜的反射面之间的距离为 -0.581mm，第四反射镜的反射面与成像区所在的第二面之间的距离为0.581mm。对应于表3的平板镜头，成像区的像面上所有视场的点列图基本落在探测器像素的尺寸范围内，由此该平板镜头具有接近于衍射理论极限的聚焦特性。此外，该平板镜头在空间频率为80线对/毫米(lp/mm)位置处的对比度大于0.3，成像清晰。上述反射面与反射面之间的距离可以指反射面偏心后沿光轴方向之间的距离。上述反射镜的反射面与第一面或第二面的距离指沿光轴方向，反射面与光轴的交点距第一面或第二面的距离。对比表2和表3，对于四次反射结构，在保证成像质量的前提下，通过减小各反射镜的曲率半径并优化各反射面之间的距离，可以进一步减小平板镜头的厚度。
例如，图13为本公开实施例的另一示例提供的平板镜头的截面结构示意图。如图13所示，平板镜头包括彼此相对的第一面100和第二面200。第一面100包括环形透光区110以及被环形透光区110包围的第一反射区120，第二面200包括成像区210以及围绕成像区210的第二反射区220。第二反射区220被配置为将从环形透光区110入射的光线反射至第一反射区120，第一反射区120被配置为将从第二反射区220射向第一反射区120的光线反射至成像区210。从环形透光区110入射的光线在进入成像区210之前仅经过第一反射区120和第二反射区220的反射，也就是，从环形透光区110入射到平板镜头的光线没有经过任何透镜的透射，仅是经过第一反射区120和第二反射区220组成的反射系统的反射后入射至位于成像区210的传感器中，由此，可以消除成像过程产生的色差。例如，上述光线的反射过程中可以采用空气作为光线传播介质，能够有效降低平板镜头的生产成本。
例如，如图13所示，第二反射区220包括与环形透光区110正对的第一反射镜221，第一反射镜221被配置为将通过环形透光区110入射至第一反射镜221的光线直接反射至第一反射区120。第一反射镜221为自由曲面反射镜、非球面反射镜以及球面反射镜之一，第一反射区120包括自由曲面反射镜、非球面反射镜、球面反射镜以及平面反射镜的至少之一。上述第一反射镜与环形透光区在图7所示的Y方向正对，Y方向可以为入射到环形透光区的光线的方向。本公开实施例中的第一反射镜采用自由曲面反射镜、非球面反射镜或者球面反射镜，可以将从环形透光区入射的光更好的会聚至第一反射区。
例如，如图13所示，第一面100和第二面200可以均为平面。但不限于此，第一面和第二面的至少之一也可以为曲面。
例如，第一反射区120包括靠近环形透光区110的第二反射镜121，第一反射镜221被配置为将环形透光区110入射至其上的光反射至第二反射镜121。例如，如图13所示，第二反射区220还包括位于第一反射镜221与成像区210之间的第三反射镜222，第三反射镜222围绕成像区210，第一反射区120还包括位于第二反射镜121远离环形透光区110一侧的第四反射镜122，第二反射镜121被配置为将入射至第二反射镜121的光线反射至第三反射镜222，第三反射镜222被配置为将入射至第三反射镜222的光线反射至第四反射镜122。例如，如图13所示，第二反射区220还包括位于第三反射镜222与成像区210之间的第五反射镜223，第五反射镜223围绕成像区210，第一反射区120还包括位于第四反射镜122远离环形透光区110一侧的第六反射镜123，第四反射镜122被配置为将入射至第四反射镜122的光线反射至第五反射镜223，第五反射镜223被配置为将入射至第五反射镜223的光线反射至第六反射镜123，第六反射镜123被配置为将入射至第六反射镜123的光线直接反射至成像区210。由此，平板镜头包括上述通过六次反射将从环形透光区入射的光反射至成像区的六次反射结构。采用六次反射结构的平板镜头的厚度可以进一步减小，例如平板镜头的厚度小于1毫米。
例如，第一反射镜221、第二反射镜121、第三反射镜222、第四反射镜122、第五反射镜223以及第六反射镜123均可以为球面反射镜。例如，第一反射镜221可以为非球面反射镜或者自由曲面反射镜，第二反射镜121、第三反射镜222、第四反射镜122、第五反射镜223以及第六反射镜123可以为平面反射镜或球面反射镜以更好的保证平板镜头的成像质量。本公开实施例中，在保证成像质量的前提下，尽量使用平面反射镜或球面反射镜，减少自由曲面反射镜和非球面反射镜的使用可以节约成本。
例如，第一反射区120和第二反射区220设置的平面反射镜和球面反射镜的数量之和大于自由曲面反射镜和非球面反射镜的数量之和，以在保证平板镜头的成像质量的基础上，可以节约制作成本。
例如，平板镜头的厚度小于2毫米。本公开实施例中的平板镜头通过第一反射区和第二反射区实现多次反射折叠技术，可以在保证像质的同时，减小平板镜头的厚度，实现光路结构紧凑的平板镜头。
例如，第一反射镜、第三反射镜和第五反射镜为彼此间隔的同心环结构以将从环形透光区入射的光更好的会聚到成像区。例如，第二反射镜、第四反射 镜以及第六反射镜为彼此间隔的同心结构以将从环形透光区入射的光更好的会聚到成像区。例如，第六反射镜可以为环状，但不限于此，还可以为圆形、方形等结构，只要可以将入射至第六反射镜的光线反射至成像区即可。例如，位于同一反射面的至少两个反射镜之间可以设有间隔，但不限于此，位于同一反射面的至少两个反射镜还可以彼此相接。
例如，环形透光区110的环宽与第一反射区120的最大尺寸之比不大于1。本公开实施例中通过对第一反射区的最大尺寸与环形透光区的环宽之比的设计，可以在保证进入平板镜头的光线亮度以及入射至成像区的光线亮度的同时，尽量减小平板镜头的厚度。
例如，第二反射区中的至少一个反射镜的表面设有反射膜以减少入射到成像区的光线的杂散光。例如，第一反射镜、第三反射镜和第五反射镜的至少一个的反射面可以设置反射膜，反射膜可以完全覆盖相应反射镜的反射面。但不限于此，也可以覆盖相应反射镜的部分反射面。本示例中的反射膜可以与图4所示示例中的反射膜具有相同的特征，在此不再赘述。
例如，本公开实施例各示例中，平板镜头的第一面和第二面的至少之一可以为光学塑料基底。位于同一面上的反射镜可以采用金刚石切削加工模具，然后用注塑成型的加工方法，从而实现大批量生产。
金刚石切削技术可以用于制造高质量的红外光学器件，也可以用于制作产生可见光的良好表面图形，由此，对于薄型、高质量成像的需求的光学系统可利用这项技术得到进一步的满足。
图14为根据本公开另一实施例提供的一种光学成像系统的局部剖面结构示意图，包括上述任一示例提供的平板镜头，图14示意性的示出光学成像系统中的平板镜头为图10所示的平板镜头。如图14所示，光学成像系统还包括传感器300，传感器300位于平板镜头的成像区，从环形透光区110入射的光线在进入传感器300之前仅经过第一反射区和所述第二反射区的反射。也就是，从环形透光区110入射到平板镜头的光线没有经过任何透镜的透射，仅是经过第一反射区120和第二反射区220组成的反射系统的反射后入射至成像区210的传感器300，可以减小光学成像系统的厚度。
例如，如图14所示，传感器300完全覆盖成像区以使反射至成像区的光线可以都被传感器300接收以将光信号转换为电信号。例如，传感器300可以包括电荷耦合器件(Charge Coupled Device，CCD)或者互补金属氧化物半导 体图像传感器(Complementary Metal-Oxide-Semiconductor，CMOS)。
例如，如图14所示，传感器300可以直接贴合在平板镜头的成像区，两者之间不存在其他透镜等光学结构，以进一步减小光学成像系统的厚度。例如，传感器可以嵌入平板镜头中以进一步减小光学成像系统的厚度。
例如，本公开实施例提供的光学成像系统可以为手机或便携式相机等器件，通过设计轻薄的平板镜头，可以实现手机或相机等光学成像系统的轻薄化。
例如，图15为根据本公开实施例的另一示例提供的光学成像系统的平面结构示意图。图15示意性的示出平板镜头的第一面的结构，如图15所示，多个平板镜头可以位于同一基底上，由此，可利用视场拼接的方法，将多个平板镜头进行视场拼接得到具有大视场高分辨的超薄光场相机等光学成像系统。
有以下几点需要说明：
(1)本公开的实施例附图中，只涉及到与本公开实施例涉及到的结构，其他结构可参考通常设计。
(2)在不冲突的情况下，本公开的同一实施例及不同实施例中的特征可以相互组合。
以上所述仅是本公开的示范性实施方式，而非用于限制本公开的保护范围，本公开的保护范围由所附的权利要求确定。

Claims (18)

  1. 一种平板镜头，包括：
    彼此相对的第一面和第二面，所述第一面包括环形透光区以及被所述环形透光区包围的第一反射区，所述第二面包括成像区以及围绕所述成像区的第二反射区，
    其中，所述第二反射区被配置为将从所述环形透光区入射的光线反射至所述第一反射区，所述第一反射区被配置为将入射至所述第一反射区的光线反射至所述成像区；
    所述第二反射区包括第一反射镜，所述第一反射镜被配置为将通过所述环形透光区入射至所述第一反射镜的光线直接反射至所述第一反射区，所述第一反射镜为自由曲面反射镜、非球面反射镜以及球面反射镜之一，所述第一反射区包括自由曲面反射镜、非球面反射镜、球面反射镜以及平面反射镜的至少之一。
  2. 根据权利要求1所述的平板镜头，其中，所述平板镜头的厚度小于3毫米。
  3. 根据权利要求1或2所述的平板镜头，其中，所述第一反射镜为环形反射镜，所述环形透光区在所述第二面上的正投影完全落入所述第一反射镜在所述第二面上的正投影内。
  4. 根据权利要求3所述的平板镜头，其中，所述第一反射镜外轮廓最大尺寸与所述环形透光区的外轮廓的最大尺寸之比大于1且小于1.5。
  5. 根据权利要求1-4任一项所述的平板镜头，其中，所述第一反射区的最大尺寸与所述环形透光区的环宽之比大于0.5。
  6. 根据权利要求1-5任一项所述的平板镜头，其中，所述第一反射区和所述第二反射区设置的平面反射镜和球面反射镜的数量之和大于自由曲面反射镜和非球面反射镜的数量之和。
  7. 根据权利要求1-6任一项所述的平板镜头，其中，入射到所述平板镜头的光线的最大视场角为10°。
  8. 根据权利要求1-7任一项所述的平板镜头，其中，所述第一反射区包括靠近所述环形透光区的第二反射镜，所述第一反射镜被配置为将从所述环形透光区入射的光线反射至所述第二反射镜。
  9. 根据权利要求8所述的平板镜头，其中，所述第二反射镜被配置为将入射至所述第二反射镜的光线直接反射至所述成像区，所述第二反射镜为平面反射镜或球面反射镜。
  10. 根据权利要求8所述的平板镜头，其中，所述第二反射镜被配置为将入射至所述第二反射镜的光线直接反射至所述成像区，所述第一反射镜和所述第二反射镜均为非球面反射镜，且所述平板镜头的厚度不大于2毫米。
  11. 根据权利要求8所述的平板镜头，其中，所述第二反射区还包括位于所述第一反射镜与所述成像区之间的第三反射镜，所述第三反射镜围绕所述成像区，所述第一反射区还包括位于所述第二反射镜远离所述环形透光区一侧的第四反射镜，所述第二反射镜被配置为将入射至所述第二反射镜的光线反射至所述第三反射镜，所述第三反射镜被配置为将入射至所述第三反射镜的光线反射至所述第四反射镜。
  12. 根据权利要求11所述的平板镜头，其中，所述第一反射镜和所述第三反射镜为同心环结构，和/或，所述第二反射镜与所述第四反射镜为同心结构。
  13. 根据权利要求11或12所述的平板镜头，其中，所述第四反射镜被配置为将入射至所述第四反射镜的光线直接反射至所述成像区，所述第二反射镜、所述第三反射镜以及所述第四反射镜均为平面反射镜或球面反射镜。
  14. 根据权利要求11或12所述的平板镜头，其中，所述第四反射镜被配置为将入射至所述第四反射镜的光线直接反射至所述成像区，所述第一反射镜和所述第四反射镜为非球面反射镜，所述第二反射镜为自由曲面反射镜，且所述第三反射镜为平面反射镜。
  15. 根据权利要求14所述的平板镜头，其中，所述平板镜头的厚度不大于2毫米。
  16. 根据权利要求11所述的平板镜头，其中，所述第二反射区还包括位于所述第三反射镜与所述成像区之间的第五反射镜，所述第五反射镜围绕所述成像区，所述第一反射区还包括位于所述第四反射镜远离所述环形透光区一侧的第六反射镜，所述第四反射镜被配置为将入射至所述第四反射镜的光线反射至所述第五反射镜，所述第五反射镜被配置为将入射至所述第五反射镜的光线反射至所述第六反射镜。
  17. 根据权利要求16所述的平板镜头，其中，所述第六反射镜被配置为将入射至所述第六反射镜的光线直接反射至所述成像区，所述第二反射镜、所 述第三反射镜、所述第四反射镜、所述第五反射镜以及所述第六反射镜均为平面反射镜或球面反射镜。
  18. 一种光学成像系统，包括：
    权利要求1-17任一项所述的平板镜头以及传感器，
    其中，所述传感器位于所述平板镜头的所述成像区，从所述环形透光区入射的光线在进入所述传感器之前仅经过所述第一反射区和所述第二反射区的反射。
PCT/CN2021/094758 2020-06-24 2021-05-20 平板镜头以及光学成像系统 WO2021258932A1 (zh)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US17/778,038 US20220390727A1 (en) 2020-06-24 2021-05-20 Flat-plate lens and optical imaging system

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN202010592563.XA CN113835193B (zh) 2020-06-24 2020-06-24 平板镜头以及光学成像系统
CN202010592563.X 2020-06-24

Publications (1)

Publication Number Publication Date
WO2021258932A1 true WO2021258932A1 (zh) 2021-12-30

Family

ID=78964979

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2021/094758 WO2021258932A1 (zh) 2020-06-24 2021-05-20 平板镜头以及光学成像系统

Country Status (3)

Country Link
US (1) US20220390727A1 (zh)
CN (1) CN113835193B (zh)
WO (1) WO2021258932A1 (zh)

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101581828A (zh) * 2009-06-09 2009-11-18 苏州大学 环形孔径超薄光学成像系统
US20110317294A1 (en) * 2010-06-25 2011-12-29 United States Of America, As Represented By The Secretary Of The Army Multi-field of view annular folded optics
US20150168681A1 (en) * 2013-12-12 2015-06-18 Samsung Electronics Co., Ltd. Zoom lens and image pickup apparatus including the same
CN105046305A (zh) * 2015-08-28 2015-11-11 南京邮电大学 一种基于环型孔径超薄透镜的微光学标签系统
CN108513666A (zh) * 2018-03-22 2018-09-07 深圳市汇顶科技股份有限公司 屏下生物特征识别装置和电子设备
CN109407290A (zh) * 2018-07-15 2019-03-01 天津大学 折叠式超薄光学成像系统
CN109870792A (zh) * 2017-12-01 2019-06-11 中国人民解放军国防科技大学 共轴全反式光学成像系统
CN111880298A (zh) * 2020-08-12 2020-11-03 长春理工大学 含有多层衍射结构的环形孔径超薄宽波段成像系统

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9001406B2 (en) * 2010-12-20 2015-04-07 Hewlett-Packard Development Company, L.P. Reflective display utilizing luminescence
CN107942416A (zh) * 2017-11-15 2018-04-20 中国科学院长春光学精密机械与物理研究所 一种环带自由曲面光学元件及单片式光学系统

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101581828A (zh) * 2009-06-09 2009-11-18 苏州大学 环形孔径超薄光学成像系统
US20110317294A1 (en) * 2010-06-25 2011-12-29 United States Of America, As Represented By The Secretary Of The Army Multi-field of view annular folded optics
US20150168681A1 (en) * 2013-12-12 2015-06-18 Samsung Electronics Co., Ltd. Zoom lens and image pickup apparatus including the same
CN105046305A (zh) * 2015-08-28 2015-11-11 南京邮电大学 一种基于环型孔径超薄透镜的微光学标签系统
CN109870792A (zh) * 2017-12-01 2019-06-11 中国人民解放军国防科技大学 共轴全反式光学成像系统
CN108513666A (zh) * 2018-03-22 2018-09-07 深圳市汇顶科技股份有限公司 屏下生物特征识别装置和电子设备
CN109407290A (zh) * 2018-07-15 2019-03-01 天津大学 折叠式超薄光学成像系统
CN111880298A (zh) * 2020-08-12 2020-11-03 长春理工大学 含有多层衍射结构的环形孔径超薄宽波段成像系统

Also Published As

Publication number Publication date
US20220390727A1 (en) 2022-12-08
CN113835193B (zh) 2023-11-03
CN113835193A (zh) 2021-12-24

Similar Documents

Publication Publication Date Title
TWI664462B (zh) 光學成像鏡頭
TWI459027B (zh) 光學成像鏡頭及應用此鏡頭之電子裝置
TWI490588B (zh) 光學成像鏡頭及應用此鏡頭之電子裝置
TWI503565B (zh) 光學成像鏡頭及應用此鏡頭之電子裝置
CN109270666B (zh) 一种光学成像镜头及电子设备
TWI516793B (zh) 可攜式電子裝置與其光學成像鏡頭
TW201523062A (zh) 可攜式電子裝置與其光學成像鏡頭
TW201348732A (zh) 光學成像鏡頭及應用此鏡頭之電子裝置
CN102033300A (zh) 全景透镜及使用该全景透镜的全景拍摄系统
WO2021007930A1 (zh) 一种近距离成像用微型成像镜头
CN213338185U (zh) 一种定焦镜头
TWI734593B (zh) 光學成像鏡頭
TW201317656A (zh) 三片式光學成像鏡頭及應用該鏡頭的電子裝置
TW202217389A (zh) 光學成像鏡頭
TW202001332A (zh) 鏡頭及其製造方法
TW201809780A (zh) 光學成像鏡頭
CN104199172B (zh) 一种取像镜头
CN111983788A (zh) 一种广角镜头
WO2021258932A1 (zh) 平板镜头以及光学成像系统
TWI807478B (zh) 光學成像系統、取像裝置及電子設備
TW201732351A (zh) 光學鏡片組
CN208013522U (zh) 广角镜头
CN208076813U (zh) 一种大视场、高像质、小畸变的光学成像系统
KR101903031B1 (ko) 가시광선 영역과 원적외선 영역을 동시에 사용할 수 있는 전방위 광학 시스템
CN212483964U (zh) 一种广角镜头

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 21828344

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 21828344

Country of ref document: EP

Kind code of ref document: A1

32PN Ep: public notification in the ep bulletin as address of the adressee cannot be established

Free format text: NOTING OF LOSS OF RIGHTS PURSUANT TO RULE 112(1) EPC (EPO FORM 1205A DATED 22/09/2023)

122 Ep: pct application non-entry in european phase

Ref document number: 21828344

Country of ref document: EP

Kind code of ref document: A1