WO2023001005A1 - 光学镜头和光学感测系统 - Google Patents

光学镜头和光学感测系统 Download PDF

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Publication number
WO2023001005A1
WO2023001005A1 PCT/CN2022/104867 CN2022104867W WO2023001005A1 WO 2023001005 A1 WO2023001005 A1 WO 2023001005A1 CN 2022104867 W CN2022104867 W CN 2022104867W WO 2023001005 A1 WO2023001005 A1 WO 2023001005A1
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Prior art keywords
medium
lens
light
optical
refracted
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PCT/CN2022/104867
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English (en)
French (fr)
Inventor
范成至
周正三
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神盾股份有限公司
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Publication of WO2023001005A1 publication Critical patent/WO2023001005A1/zh

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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B3/00—Simple or compound lenses
    • G02B3/02—Simple or compound lenses with non-spherical faces
    • G02B3/08—Simple or compound lenses with non-spherical faces with discontinuous faces, e.g. Fresnel lens
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J1/00—Photometry, e.g. photographic exposure meter
    • G01J1/42—Photometry, e.g. photographic exposure meter using electric radiation detectors
    • G01J1/44—Electric circuits
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J1/00—Photometry, e.g. photographic exposure meter
    • G01J1/42—Photometry, e.g. photographic exposure meter using electric radiation detectors
    • G01J1/4204—Photometry, e.g. photographic exposure meter using electric radiation detectors with determination of ambient light
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
    • G01S17/02—Systems using the reflection of electromagnetic waves other than radio waves
    • G01S17/06—Systems determining position data of a target
    • G01S17/08—Systems determining position data of a target for measuring distance only
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
    • G01S7/483—Details of pulse systems
    • G01S7/486—Receivers
    • G01S7/4861—Circuits for detection, sampling, integration or read-out
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J1/00—Photometry, e.g. photographic exposure meter
    • G01J1/42—Photometry, e.g. photographic exposure meter using electric radiation detectors
    • G01J1/44—Electric circuits
    • G01J2001/4413—Type
    • G01J2001/442—Single-photon detection or photon counting
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J1/00—Photometry, e.g. photographic exposure meter
    • G01J1/42—Photometry, e.g. photographic exposure meter using electric radiation detectors
    • G01J1/44—Electric circuits
    • G01J2001/4446—Type of detector
    • G01J2001/446—Photodiode
    • G01J2001/4466—Avalanche

Definitions

  • the present disclosure relates to the technical field of optical sensing, and more particularly, to an optical lens and an optical sensing system.
  • Time Of Flight (TOF) detection technology refers to a technology that detects the flight (round-trip) time of infrared light pulses to achieve target object positioning. Because this technology has strong anti-interference and high refresh rate of frames per second, etc. It has unique advantages in face recognition, stereoscopic imaging, and somatosensory interaction.
  • TOF optical lenses are more and more widely used in electronic devices such as smartphones, tablet computers, and e-readers, and the industry’s requirements for TOF optical lenses are also getting higher and higher.
  • TOF optical lenses configured on electronic products are required to have the characteristics of small size; on the other hand, since the most iconic function of TOF detection technology is to measure data such as depth of field Therefore, the TOF optical lens is required to have a wide viewing angle to meet the needs of detecting a larger scene range.
  • the glass has a low refractive index, resulting in a small field of view of the TOF optical lens, the range of light received by the optical sensor through the optical lens is small, and less scene information is captured.
  • the current research on enlarging the field of view of the optical lens mostly focuses on how to design glass lens groups to expand the field of view of the optical lens, but the use of complex glass lens groups will lead to increased volume and weight of the optical lens. Therefore, there is a need for an optical lens that can receive light of a specific wavelength band, has a simple structure and has a larger field of view, so as to capture scene information at a larger angle and meet the demand for detecting a larger scene range.
  • the present disclosure arranges a lens in the optical lens, and fills or forms a medium with a refractive index less than or equal to the lens behind the lens, thereby expanding the field of view of the optical lens that receives light of a specific wavelength band, and can capture a larger angle scene information to meet the demand for detection of a larger scene range.
  • An embodiment of the present disclosure provides an optical lens, which sequentially includes along the light transmission direction: a lens configured to refract an incident light incident on its light incident surface, the incident light is refracted into a refracted light, the A light incident surface of the lens is located on the first side of the lens, wherein the incident light is long-wavelength invisible light; and a medium is arranged on the second side of the lens and is configured to be between the lens and the The refracted light is refracted at the interface of the medium, wherein the refractive index of the lens is greater than or equal to the refractive index of the medium, and the refractive index of the medium is greater than the refractive index of air.
  • the lens is a positive lens
  • the positive lens is a Fresnel lens
  • the first side of the lens is convex and/or has a stepped structure
  • the second side of the lens is flat and adheres to the first side of the medium.
  • the refractive index of the lens is greater than the first value.
  • the invisible light is light with a wavelength greater than 1 micron, and the transmittance of the lens to the invisible light is higher than a second value.
  • the field angle of the optical lens is larger than the third value.
  • the first value is 3.5
  • the second value is 55%
  • the third value is 60 degrees.
  • the lens is any one of the following: a silicon lens, a germanium lens, a gallium phosphide lens, an indium phosphide lens, and a lead sulfide lens.
  • the medium includes: a first medium and a second medium; the first medium is located between the lens and the second medium, and is configured to be between the lens and the first medium
  • the refracted ray is refracted at the interface of the first medium, the refracted ray is refracted into a first transmitted ray and propagates to the interface of the first medium and the second medium; and the second medium is located at the first medium a medium away from the lens side, configured to refract the first transmitted light at the interface between the first medium and the second medium, and the first transmitted light is refracted into a second transmitted light .
  • the refractive index of the first medium is greater than the refractive index of the second medium, and the refractive index of the second medium is greater than or equal to the refractive index of air.
  • the first medium is a solid medium
  • the second medium is a solid, liquid or gaseous medium
  • the medium is a solid, liquid or gaseous medium.
  • the medium is oil or water.
  • the optical lens further includes: at least one filter layer, wherein each filter layer is located between the lens and the medium, or located on a side of the medium away from the lens, Or on the side of the lens away from the medium.
  • An embodiment of the present disclosure also provides an optical sensing system, which sequentially includes a lens, a medium, and an optical sensor along the light transmission direction: the lens is configured to refract the incident light incident on its light incident surface, so The incident light is refracted into refracted light, and the incident surface of the lens is located on the first side of the lens, wherein the incident light is long-wavelength invisible light; the medium is arranged on the second side of the lens side, and is configured to refract the refracted light at the interface of the lens and the medium, the refracted light propagates in the medium, and is captured at the interface of the medium and the optical sensor refracting outgoing light rays, the lens on a first side of the medium; and the optical sensor, disposed on a second side of the medium, configured to receive the outgoing light rays and generate optical light based on the outgoing light rays sensing signal.
  • the refractive index of the lens is greater than or equal to the refractive index of the medium, and the refractive index of the medium is greater than that of air.
  • the optical sensing system further includes: at least one filter layer, wherein each filter layer is located between the lens and the medium, or located on a side of the medium away from the lens. side, or on the side of the lens away from the medium.
  • the lens in the optical sensing system, is coaxial with the optical sensor.
  • the viewing angle of the optical lens for receiving light of a specific wavelength band can be expanded, scene information of a larger angle can be captured, and the requirement for detecting a larger scene range can be met.
  • FIGS. 1A and 1B show schematic diagrams of optical lens structures according to embodiments of the present disclosure
  • FIG. 2A shows a schematic diagram of an exit position of an exit light in an optical lens according to an embodiment of the present disclosure
  • 2B shows a schematic diagram of the imaging position when the optical sensor is directly arranged at the light exit surface of the medium of the optical lens according to an embodiment of the present disclosure
  • Figure 2C shows a schematic diagram of the imaging position when the optical lens is not filled with medium
  • FIG. 3 shows another schematic diagram of an optical lens structure according to an embodiment of the disclosure
  • 4A and 4B show a schematic structural view of an optical sensing system according to an embodiment of the present disclosure
  • FIG. 5A shows a schematic diagram of an imaging position in an optical sensing system according to an embodiment of the present disclosure
  • Fig. 5B shows a schematic diagram of the imaging position when no medium is filled in the optical sensing system
  • FIG. 6 shows another schematic structural diagram of an optical sensing system according to an embodiment of the present disclosure
  • FIG. 7 shows a schematic diagram of the field of view expansion effect of the optical sensing system according to an embodiment of the disclosure.
  • connection or “connection” are not limited to direct connection, but can also be indirect connection; words like “interface” are not limited to direct connection. Forming the interface may also be through another medium.
  • Time Of Flight (TOF) detection technology adopts active light detection method to emit detection light waves to the object under test.
  • the light waves are reflected back after encountering the object, and are collected by the optical sensor through the optical lens.
  • the optical sensor receives the reflected light waves and
  • the received light waves are converted into optical sensing signals, and the optical sensing system calculates the distance between the measured object and the optical sensor by calculating the pulse difference or time difference between the emitted and received light waves.
  • the optical sensing signal can be used to generate an image of the scene to support a variety of applications, such as time-of-flight ranging, depth sensing, position tracking, etc.
  • the angle formed by the two edges of the maximum range of the object to be measured can pass through the optical lens with the imaging plane of the optical lens as the vertex is called the field of view angle of the optical lens (Field of view, FOV), which determines the angle range of the scene that the optical sensor can image.
  • FOV Field of view
  • the light reflected by the object has a larger angle range of the imaged scene, and more scene information can be captured.
  • FIGS. 1A and 1B show schematic diagrams of the structure of an optical lens 100 according to an embodiment of the present disclosure.
  • an embodiment of the present disclosure provides an optical lens 100 , which sequentially includes a lens 101 and a medium 102 along a light transmission direction.
  • the lens 101 is configured to refract an incident ray 103 incident on its light incident surface, the incident ray is refracted at the incident point A on the light incident surface and is refracted into a refracted ray 104, the lens
  • the light incident surface is located on the first side of the lens, wherein the incident light 103 is long-wavelength invisible light, that is, the incident light is invisible light with a wavelength longer than that of visible light.
  • the first side of the lens is a side away from the medium 102
  • the second side of the lens is a side close to the medium 102 .
  • the medium 102 is arranged on the second side of the lens 101 and is configured to refract the refracted light ray 104 at an interface (hereinafter referred to as a first interface) between the lens 101 and the medium 102 .
  • a first interface an interface between the lens 101 and the medium 102 .
  • the first side of the medium 102 is close to the lens 101 and serves as the light incident surface of the medium 102
  • the second side of the lens 101 serves as the light exit surface of the lens 101
  • the medium The second side of 102 is far away from the lens 101 and serves as the light exit surface of the medium 102 .
  • the refracted light ray 104 is refracted at point B on the first interface, the refracted light propagates in the medium 102, and is refracted again at point C at the light exit surface of the medium 102 , and is refracted as the outgoing ray 106 .
  • the refracted light propagates in the medium 102 , during which the refracted light may be refracted again.
  • the medium 202 may be composed of multi-layer media, then during the propagation of the refracted light in the medium 202, the refraction may occur multiple times at the interface of the multi-layer media.
  • the medium 102 may be a single-layer medium structure, or may include a first medium and a second medium.
  • the refracted ray 104 is refracted at point B on the first interface and is refracted into a first transmitted ray 105, and the The point C of the first transmitted light 105 on the light-emitting surface of the medium 102 is refracted into the outgoing light 106 .
  • the refractive index of the lens 101 is greater than or equal to the refractive index of the medium 102 , and the refractive index of the medium 102 is greater than that of air.
  • the refractive index of the medium 102 may be an equivalent refractive index, for example, in the case where the medium 102 is a single-layer medium structure, the refractive index of the medium 102 is the refractive index of the single-layer medium;
  • the refractive index of the medium 102 is the equivalent refractive index of the double-layer dielectric structure.
  • the equivalent refractive index may be determined by the refractive index and thickness of the first medium, and the refractive index and thickness of the second medium.
  • the refractive index of the lens 101 is greater than a first value, and the first value may be 2.5, 3, 3.5, 4, etc., preferably, the first value is 3.5.
  • the lens may be a silicon lens containing a silicon material, a germanium lens containing a germanium material, a gallium phosphide lens containing a gallium phosphide material, an indium phosphide lens containing an indium phosphide material, or a lead sulfide lens. Material lead sulfide lens etc.
  • the lens is a silicon lens made of silicon material.
  • the invisible light is light with a wavelength greater than 1 micron, and the transmittance of the lens to the invisible light is higher than a second value.
  • the wavelength of the invisible light may be 1 micron to 6 microns, and the second value may be 50%-60%.
  • the second value is 55%.
  • the refractive index of the lens 101 is greater than or equal to the refractive index of the medium 102, the refractive index of the medium 102 is greater than the refractive index of air, and the field angle of the optical lens 100 is greater than a third value .
  • the third value is between 60 degrees and 120 degrees.
  • the third value is 60 degrees.
  • the lens 101 is a silicon lens
  • the incident light 103 is infrared light with a wavelength greater than 1 micron
  • the silicon lens has a wavelength greater than
  • the light band of 1 micron has good light transmission performance.
  • the transmittance of silicon lens for infrared light is greater than 55% and the transmittance for visible light is very low, so it can efficiently transmit infrared light and effectively shield visible light at the same time .
  • the refractive index of a silicon lens is about 3.5, which is greater than that of glass (about 1.5), and the angle of view of an optical lens using a glass lens is about 60 degrees.
  • Point B is refracted again, and is refracted as the first transmission
  • the light 105 uses the following equation to calculate the refraction angle of the first transmitted light 105:
  • ⁇ s is the included angle between the refracted ray 104 and the normal line at point B on the first interface, that is, it is equivalent to the incident angle of the refracted ray 104 to the incident surface of the medium 102
  • ⁇ c is the first The included angle between the transmitted ray 105 and the normal at point B on the first interface, that is, the refraction angle of the first transmitted ray 105 at point B
  • n s is the refractive index of the lens 101
  • n c is the refractive index of the medium 102 .
  • the normal at point B on the first interface is shown by a dashed line passing through point B.
  • FIG. 2A the normal at point B on the first interface is shown by a dashed line passing through point B.
  • the following equation is used to calculate the lateral distance H c from point B on the first interface to the exit position (i.e., point C) of the exit light 106 on the light exit surface of the medium 102:
  • d is the thickness of the medium 102
  • ⁇ ⁇ is the incident angle of the refracted ray 104 at the light incident surface of the medium 102 at the point B
  • ⁇ c is the refraction angle of the first transmitted ray 105 at the point B
  • n s is The refractive index of the lens 101
  • n c is the refractive index of the medium 102 .
  • the medium 102 is a solid, liquid or gaseous medium.
  • the thickness d of the medium is greater than the thickness of the lens.
  • the medium 102 can be made of glass, plastic, resin, FRP, airgel, water, oil, alcohol, carbon dioxide, etc.
  • Different types of medium 102 have different refractive indices n c , and the refractive index n c are smaller than the refractive index n s of the lens 101 .
  • the refractive index nc is about 1.5
  • the refractive index ns of the lens 101 is 3.5
  • the medium thickness is d
  • the lateral distance H between point B and point C shown in Figure 2A can be calculated c for
  • the outgoing light 106 in FIG. 2A may enter another medium for propagation, or may directly irradiate the optical sensor and be sensed by the optical sensor.
  • the transmission length of the outgoing light 106 is very short, even negligible.
  • the magnitude of ⁇ c is the same as that of ⁇ s
  • the point B on the first interface to the outgoing ray can also be calculated according to the above equation.
  • 106 is the lateral distance of the emitting position (namely, point C) on the light emitting surface of the medium 102 , and the lateral distance is smaller than the lateral distance H c shown in FIG. 2A .
  • FIG. 2B shows a schematic illustration of the imaging position in the case where the optical sensor is arranged directly on the light exit surface of the medium 102 .
  • the point C shown in Figure 2A can be approximated as the imaging point of the incident light 103 on the optical sensor, and the interface between the medium 102 and the optical sensor can be called the second interface , and point C can be called point C on the second interface.
  • the distance between the imaging point C and the incident point A of the incident ray 103 can be expressed as the sum of the lateral distance from point A to point B and the lateral distance from point B to point C. It can be understood that when the parameters of the lens 101 are fixed, the lateral distance between point A and point B is also fixed, then the distance between imaging point C and incident point A is directly determined by the distance between point B and point C The lateral distance is determined.
  • the medium 102 under the lens 101 and the refractive index of the medium 102 is greater than that of air, it is possible to make: compared with an optical lens without the medium 102, the distance between point B and point C The lateral distance is reduced, thereby reducing the distance between the imaging point C and the incident point A, so that the field angle of the optical lens 100 can be increased when the size of the optical sensor is fixed.
  • FIG. 2C a schematic diagram of the imaging position in the case where the medium 102 is not arranged and the optical sensor is arranged at a position d away from the light-emitting surface of the lens 101 is shown in FIG. 2C Show.
  • the refracted ray 104 is refracted at point B on the first interface and is refracted into a first transmitted ray 105, the first transmitted ray 105 propagates through the air, and at point C on the second interface onto the optical sensor.
  • the lateral distance H a between point B and point C in Fig. 2C can also be calculated by using the above formula as
  • the lateral distance H c gradually decreases. Therefore, when the size of the optical sensor is fixed (such as a square of 1cm*1cm or a circle with a radius of 1cm), the parameters of the lens are constant, and the distance between the light-emitting surface of the lens and the optical sensor (ie d) is constant, In the case of directly providing the air layer without filling the medium 102, assuming that the field of view of the optical lens is 60°, after filling the medium 102, since the refractive index n c of the medium 102 is greater than the refractive index 1 of the air, then the lateral distance H The reduction of c means that the image formed by the same target is reduced, so that the optical sensor can image a target in a wider range, that is, the field angle of the optical lens is greater than 60°.
  • the viewing angle of the optical lens also increases.
  • the size of the optical sensor is fixed, by properly setting the parameters of the lens 101 and the refractive index nc of the medium 102, the thickness d of the medium 102 can also be reduced, thereby further helping to reduce the thickness of the electronic product.
  • the diameter of the lens 101 when the diameter of the lens 101 is fixed, the larger the refractive index n c of the medium 102, the smaller the lateral distance H c from point B on the first interface to point C on the second interface, and the incident light 103 passes through The image formed behind the optical lens 100 is smaller. Then, when the size of the optical sensor is fixed, the angle range of the light rays that the optical lens 100 can receive is larger, that is, the incident angle of the incident light 103 can be larger. Therefore, by filling the medium 102 behind the lens 101 , the viewing angle of the optical lens 100 can be increased.
  • the optical sensor in the case where the optical sensor is directly arranged at the light-emitting surface of the medium 102, it is also possible to similarly calculate the points B on the first interface to the second The lateral distance H c of point C on the interface, and similarly, in the case of a fixed size of the optical sensor, as the refractive index n c of the medium 102 increases, the field angle of the optical lens also increases.
  • the thickness d of the medium 102 can also be reduced, thereby further helping to reduce the thickness of the electronic product.
  • the optical lens and the optical sensor are arranged together as shown in FIGS. There is an air gap between the optical sensors).
  • the refractive index of air is smaller than the refractive index of the medium 102, the light 106 emitted at the light exit surface of the medium 102 will propagate along the air gap, and make the optical sensor
  • the imaging position on is shifted to the left relative to point C in FIG. 2B , as shown in FIG. 2C , so that the field angle of the optical lens is slightly reduced compared to the case where there is no air gap. Therefore, in order to keep the viewing angle of the optical lens as large as possible, the thickness of the air gap (that is, the distance between the medium 102 and the optical sensor) should be small.
  • FIG. 3 shows another schematic diagram of the structure of the optical lens 100 according to an embodiment of the present disclosure.
  • the medium 102 includes a first medium 1021 and a second medium 1022; the first medium 1021 is located between the lens 101 and the second medium 1022, configured In order to refract the refracted ray 104 at the interface of the lens 101 and the first medium 1021, the refracted ray 104 is refracted into the first transmitted ray 105, and the first transmitted ray 105 propagates to the interface of the first medium 1021 and the second medium 1022 (hereinafter referred to as the third interface); and the second medium 1022 is located on the side of the first medium 1021 away from the lens 101, configured to refract the first transmitted light ray 105 at the third interface, and the first transmitted light ray 105 is refracted into a second refracted light ray 107 .
  • the refractive index of the first medium 1021 is greater than that of the second medium 1022 , and the refractive index of the second medium 1022 is greater than or equal to that of air.
  • d 1 is the thickness of the first medium 1021
  • ⁇ s is the incident angle of the refracted ray 104 on the incident surface of the first medium 1021
  • n s is the refractive index of the lens 101
  • n c1 is the refraction of the first medium 1021 Rate.
  • d 2 is the thickness of the second medium 1022
  • ⁇ s is the incident angle of the refracted ray 104 on the incident surface of the first medium 1021
  • n s is the refractive index of the lens 101
  • n c1 is the refraction of the first medium 1021 index
  • n c2 is the refractive index of the second medium 1022 .
  • the first medium 1021 is a solid medium
  • the second medium 1022 is a solid, liquid or gas medium.
  • the first medium 1021 can be made of glass, plastic, resin, FRP, airgel, etc.
  • the second medium 1022 can be made of glass, plastic, resin, FRP, aerogel, water, oil, alcohol, carbon dioxide, etc. .
  • the first interface as shown in FIG.
  • the lateral distance H c from point B on the second interface to point C on the second interface.
  • the outgoing light ray 106 may propagate into another medium, or may directly impinge on and be sensed by an optical sensor.
  • the transmission length of the outgoing light 106 is very short, even negligible.
  • the optical sensor is not explicitly shown in FIG. 3, it should be understood that an optical sensor may be arranged below the second medium 1022, and a second interface is formed between the second medium 1022 and the optical sensor, as shown in FIG. The point C on the second interface of can be approximated as the imaging point of the incident light 103 on the optical sensor.
  • an optical sensor may also be arranged at intervals from the second medium 1022 (ie, there is a small air gap between the second medium and the optical sensor).
  • the viewing angle of the optical lens can be adjusted by adjusting the thicknesses of the first medium and the second medium.
  • the optical lens may further include at least one filter layer, and each filter layer may be configured to filter out light of a specific wavelength, so that the optical sensor can detect infrared light more accurately.
  • the at least one filter layer may be arranged together, or may be arranged separately.
  • Each filter layer may be located between the lens and the medium, or may be located on a side of the medium away from the lens, or may be located on a side of the lens away from the medium.
  • incident light, refracted light, first transmitted light, second transmitted light and outgoing light described in the embodiments of the present disclosure are used to refer to different transmission stages of the same light, and the above terms are only used for different transmissions of light Phases are distinguished and are not intended to indicate different rays.
  • FIG. 4A shows a schematic structural diagram of an optical sensing system 200 according to an embodiment of the present disclosure.
  • an embodiment of the present disclosure provides an optical sensing system 200 , which sequentially includes a lens 201 , a medium 202 , and an optical sensor 203 along the light transmission direction.
  • the lens 201 is configured to refract an incident ray 204 incident on its light incident surface, and the incident ray 204 is refracted at the incident point A on the light incident surface and is refracted into a refracted ray 205, the The light incident surface of the lens is located on the first side of the lens 201 , wherein the incident light 204 is long-wavelength invisible light, that is, the incident light is invisible light with a wavelength longer than that of visible light. As shown in FIG. 4A , the first side of the lens 201 is a side away from the medium 202 , and the second side of the lens 201 is a side close to the medium 202 .
  • the medium 202 is arranged on the second side of the lens 201, and is configured to refract the refracted light ray 205 at the interface (hereinafter referred to as the first interface) between the lens 201 and the medium 202,
  • the refracted light propagates in the medium 202 and is refracted into an outgoing light 207 at the interface between the medium 202 and the optical sensor 203 (hereinafter referred to as the second interface).
  • the first side of the medium 202 is close to the lens 201 and serves as the light incident surface of the medium 202, and the second side of the lens 201 serves as the light exit surface of the lens 201, and the medium The second side of 202 is away from the lens 201 and serves as the light exit surface of the medium 202 .
  • the refracted light 205 after the refracted light 205 is refracted at the first interface, the refracted light propagates in the medium 202 , during which the refracted light may be refracted again.
  • the medium 202 may be composed of a multi-layer medium, then the refracted light may be refracted multiple times at the interface of the multi-layer medium during the propagation in the medium 202 .
  • the medium 202 may be a single-layer medium structure, or may include a first medium and a second medium.
  • the refracted ray 205 is refracted at point B on the first interface and is refracted into a first transmitted ray 206, and the The first transmitted ray 206 is refracted into an outgoing ray 207 at the interface (hereinafter referred to as the second interface) between the medium 202 and the optical sensor 203 .
  • the optical sensor 203 is disposed on the second side of the medium 202 and is configured to receive the outgoing light 207 and generate an optical sensing signal based on the outgoing light 207 .
  • the refractive index of the lens 201 is greater than or equal to the refractive index of the medium 202, and the refractive index of the medium 202 is greater than that of air.
  • the refractive index of the medium 202 is an equivalent refractive index, for example, in the case where the medium 202 may be a single-layer medium structure, the refractive index of the medium 202 is the refractive index of the single-layer medium;
  • the refractive index of the medium 202 is the equivalent refractive index of the double-layer dielectric structure.
  • the equivalent refractive index may be determined by the refractive index and thickness of the first medium, and the refractive index and thickness of the second medium.
  • the refractive index of the lens 201 is greater than a first value, and the first value may be 2.5, 3, 3.5, 4, etc., preferably, the first value is 3.5.
  • the lens 201 may be a silicon lens containing silicon material, a germanium lens containing germanium material, a gallium phosphide lens containing gallium phosphide material, an indium phosphide lens containing indium phosphide material, a Lead sulfide lenses of lead materials, etc.
  • the lens is a silicon lens made of silicon material.
  • the invisible light is light with a wavelength greater than 1 micron, and the transmittance of the lens 201 to the invisible light is higher than a second value.
  • the wavelength of the invisible light may be 1 micron to 6 microns, and the second value may be 50%-60%.
  • the second value is 55%.
  • the viewing angle of the optical sensing system 200 is larger than the third value.
  • the third value is between 60 degrees and 120 degrees.
  • the third value is 60 degrees.
  • the lens 201 is a positive lens.
  • the lens 201 may be a biconvex positive lens, a plano-convex positive lens, or a concave-convex positive lens, and has the capability of converging light.
  • the first side of the lens 201 is convex, and the second side is convex, flat or concave.
  • the lens 201 may be a Fresnel lens, and along the direction of light transmission are the textured surface and the plane of the Fresnel lens, that is, the first side of the Fresnel lens is a textured surface, and the second side of the Fresnel lens is a textured surface. The sides are flat. Because the Fresnel lens is lighter and thinner, it can avoid the phenomenon of darkening and blurring of the corners of the light.
  • the first side of the lens 201 is convex and/or has a stepped structure
  • the second side of the lens 201 is flat and adheres to the first side of the medium 202 .
  • the bonding between the second side of the lens 201 and the first side of the medium 202 may be direct bonding, or bonding through an adhesive.
  • the lens 201' in the optical sensing system shown therein has a stepped structure. It should be understood that the production process of the stepped lens 201' is simpler than that of the convex lens 201, and it is easier to manufacture, which is beneficial to reduce the production cost.
  • the field angle of the optical sensing system 200 is larger than the third value.
  • the light-incident surfaces of the lenses 201, 201' may be coated with a single-layer or multi-layer anti-reflection coating to reduce the reflection of the incident light 204 and increase the size of the lenses 201, 201' light transmittance.
  • the lens 201 is coaxial with the optical sensor 203 , and light incident from the lens 201 can be transmitted and imaged on the optical sensor 203 .
  • the long-wavelength incident light enters the The light incident surface of the lens, along the propagation direction of the light, the incident light of the long wavelength is sequentially absorbed by the light incident surface of the lens, the interface between the lens and the medium, and the light output of the medium. Surface refraction is finally refracted into outgoing light, thereby expanding the field of view angle of the optical lens for the incident light of the long-wavelength light.
  • the medium 202 in FIG. 4A and FIG. 4B can be set as shown in FIG. Between two media, the second medium is located on the side of the first medium away from the lens, the refractive index of the first medium is greater than that of the second medium, and the refractive index of the second medium is greater than or equal to the refractive index of air.
  • FIG. 5A shows a schematic diagram of imaging locations in an optical sensing system 200 according to an embodiment of the disclosure.
  • FIG. 5B shows a schematic illustration of the imaging position in the case where no medium is filled in the optical sensing system 200 and the optical sensor is arranged at a position d away from the light-emitting surface of the lens.
  • the outgoing light ray 207 is omitted in FIGS. 5A and 5B .
  • the incident ray 204 is refracted at point A on the light incident surface of the lens 201, and is refracted into a refracted ray 205, and the refracted ray 205 is refracted at the interface (first interface) between the lens 201 and the medium 202 Refraction occurs, and is refracted into the first transmitted light ray 206, according to the law of refraction, the refraction angle of the first transmitted light ray 206 can be calculated similarly using the above equation (1), and correspondingly use the above equation (2) to calculate the angle of refraction from FIG. 5A The lateral distance from point B to point C.
  • the distance H c between the imaging position on the optical sensor 203 (i.e. point C) and the point B on the first interface can be directly calculated by the above equation (2) , correspondingly, the distance between the incident point A of the incident light 204 and the imaging position point C can be determined, so that the field angle of the optical sensing system 200 can be determined.
  • the above-mentioned equations can also be used to similarly calculate the lateral distance H a from point B to point C in FIG. 5B .
  • the distance H c of FIG. 5A With the distance H a of FIG. 5B , it can be understood that when the medium 102 is filled and the refractive index of the medium 102 is greater than that of air, the lateral distance between point B and point C is smaller than that without filling
  • the lateral distance of the medium reduces the image formed by the same target, and then enables the optical sensing system 200 to image a target within a wider range, that is, the optical sensing system 200 has a larger field of view.
  • the medium 202 is a solid, liquid or gaseous medium.
  • the thickness of the medium is greater than the thickness of the lens.
  • the medium 202 can be made of glass, plastic, resin, FRP, airgel, water, oil, alcohol, carbon dioxide, etc.
  • Different types of medium 202 have different refractive indices n c , and the refractive index n c are smaller than the refractive index n s of the lens 201 .
  • the thickness d of the medium 202 can also be reduced, thereby further helping to reduce the optical sensing system 200. Thickness, even the thickness of electronic products.
  • the larger the refractive index nc of the medium 202 the greater the distance from the incident position (point B) of the refracted ray 205 to the exit position (point C ) of the outgoing ray 207
  • the smaller the lateral distance H c of the smaller the image generated on the optical sensor 203 .
  • the angle range of the scene that the optical sensing system 200 can image is larger. Therefore, by filling the medium 202 between the lens 201 and the optical sensor 203, the viewing angle of the optical sensing system 200 can be increased.
  • the size of the image on the optical sensor 203 can be reduced by increasing the thickness d of the medium 202 or reducing the refractive index nc of the medium 202 , thereby reducing the area of the optical sensor 203 .
  • FIG. 6 shows another schematic structural diagram of an optical sensing system 200 according to an embodiment of the present disclosure.
  • the optical sensing system 200 includes a lens 201 , a medium 202 and an optical sensor 203 , and the medium 202 includes a first medium 2021 and a second medium 2022 .
  • the first medium 2021 is located between the lens 201 and the second medium 2022 and is configured to be at the interface of the lens 201 and the first medium 2021
  • the refracted ray 205 is refracted at
  • the refracted ray 205 is refracted into the first transmitted ray 206
  • the first transmitted ray 206 propagates to the first medium 2021 and the second medium 2022 interface (hereinafter referred to as the third interface);
  • the second medium 2022 is located on the side of the first medium 2021 away from the lens 201, and is configured to support the first medium 2022 at the third interface.
  • the transmitted ray 206 is refracted, the first transmitted ray 206 is refracted into a second transmitted ray 208, and the second transmitted ray 208 propagates to the interface of the second medium 2022 and the optical sensor 203 (hereinafter referred to as for the second interface).
  • the second transmitted light ray 208 is refracted at the point C on the second interface, and is refracted into an outgoing light ray 207 , and the outgoing light ray 207 is irradiated onto the optical sensor 203 .
  • the outgoing light ray 207 is omitted in FIG. 6 .
  • the refractive index of the first medium 2021 is greater than the refractive index of the second medium 2022, and the refractive index of the second medium 2022 is greater than or equal to the refractive index of air.
  • d 1 is the thickness of the first medium 2021
  • ⁇ s is the incident angle of the refracted ray 205 on the incident surface of the first medium 2021
  • n s is the refractive index of the lens 201
  • n c1 is the first medium 2021 Refractive Index.
  • Fig. 6 also shows point D on the third interface (the point where the second transmitted ray 208 starts to propagate from the light incident surface of the second medium 2022) to point C on the second interface (the point where the second transmitted ray 208 208 reaches the point of the light exit surface of the second medium 2022) the lateral distance H c2 .
  • d 2 is the thickness of the second medium 2022
  • n c2 is the refractive index of the second medium 2022 .
  • the lateral distance Hc from point B on the first interface to point C on the second interface can be calculated using the above equations (5)-(7).
  • the first medium 2021 is a solid medium
  • the second medium 2022 is a solid, liquid or gas medium.
  • the first medium 2021 can be made of glass, plastic, resin, FRP, airgel, etc.
  • the second medium 2022 can be made of glass, plastic, resin, FRP, aerogel, water, oil, alcohol, carbon dioxide, etc. .
  • the thickness d 1 of the first medium 2021, the material of the first medium 2021, the thickness d 2 of the second medium 2022, and the material of the second medium 2022 can be changed to change the The lateral distance H c from point B on the third interface to point C on the third interface.
  • the thickness d of the medium 202 is fixed, the larger the thickness d1 of the first medium 2021 is, the smaller the lateral distance H c is.
  • the viewing angle of the optical sensing system can be adjusted by adjusting the thicknesses of the first medium and the second medium.
  • the optical sensor can be arranged directly under the second medium as shown in FIG. 6 , or it can be arranged spaced from the second medium (ie, there is a small air gap between the second medium and the optical sensor).
  • the optical sensing system may further include at least one filter layer, and each filter layer may be configured to filter out light of a specific wavelength, so that the optical sensor can detect infrared light more accurately .
  • the at least one filter layer may be arranged together, or may be arranged separately.
  • Each filter layer may be located between the lens and the medium, or may be located on a side of the medium away from the lens, or may be located on a side of the lens away from the medium.
  • incident light, refracted light, first transmitted light, second transmitted light and outgoing light described in the embodiments of the present disclosure are used to refer to different transmission stages of the same light, and the above terms are only used for different transmissions of light Phases are distinguished and are not intended to indicate different rays.
  • FIG. 7 is a schematic diagram showing the enlargement effect of the field angle of the optical sensing system relative to the field angle of the optical sensing system without medium filling according to an embodiment of the present disclosure.
  • FIG. 7 a schematic diagram of light transmission of an optical sensing system according to an embodiment of the present disclosure is shown by a solid line in FIG. 7
  • a light transmission of an optical sensing system without medium filling is shown by a dotted line in FIG. 7 Schematic diagram of the situation.
  • a medium 202 is shown in FIG. 7, it should be understood that for a non-medium-filled optical sensing system shown in phantom, the medium 202 is not present and the area where the medium 202 is located is filled with air.
  • the incident ray shown by the dotted line is refracted through the light incident surface of the lens 201, and the refracted ray 205 shown by the dotted line is generated, and refracted again by the light exit surface of the lens 201, and the ray shown by the dotted line is generated in the air.
  • the first transmitted light ray 206 is ⁇ .
  • the incident light 204 shown by the solid line is refracted through the light incident surface of the lens 201 to generate the refracted light 205 shown by the solid line, and is refracted again through the light exit surface of the lens 201 to generate a solid light ray 205 in the medium 202.
  • the first transmitted light ray 206 is shown by the line.
  • the incident angle of the incident light shown by the solid line is ⁇ , and ⁇ is greater than ⁇ .
  • the viewing angle at this time is 2 ⁇ .
  • the optical sensing system increases the viewing angle of the lens system compared with the traditional optical sensing system by using the lens 201 and the medium 202 with a refractive index higher than that of air.
  • the field angle of the optical lens and the optical sensing system for receiving light of a specific wavelength band can be expanded, thereby capturing scene information of a larger angle, and satisfying the requirement of detecting a larger scene range need.

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Abstract

本公开实施例提供一种光学镜头和光学感测系统。本公开的实施例所提供的光学镜头沿光线传输方向依次包括：透镜，被配置为对入射到其入光面的入射光线进行折射，所述入射光线被折射为折射光线，所述透镜的入光面位于所述透镜的第一侧，其中，所述入射光线为长波长的不可见光；以及介质，布置在所述透镜的第二侧，并且被配置为在所述透镜和所述介质的界面处对所述折射光线进行折射，其中，所述透镜的折射率大于等于所述介质的折射率，并且所述介质的折射率大于空气的折射率。

Description

光学镜头和光学感测系统 技术领域
本公开涉及光学感测技术领域，更具体地，涉及光学镜头和光学感测系统。
背景技术
飞行时间(Time Of Flight，TOF)探测技术是指通过探测红外光脉冲的飞行(往返)时间实现目标物体定位的一种技术，由于该技术具备抗干扰性强、每秒传输帧数刷新率高等特性，在人脸识别、立体成像、体感交互等方面具有独特的优势。
随着TOF探测技术的飞速发展，TOF光学镜头在智能手机、平板电脑、电子阅读器等电子设备中的应用也越来越广泛，业界对TOF光学镜头的要求也越来越高。一方面，随着电子产品的超高清以及轻薄短小化趋势，要求配置在电子产品上的TOF光学镜头具有体积小的特点；另一方面，由于TOF探测技术最标志性的功能是测量景深等数据信息，因此要求TOF光学镜头具有广视角等特点，以满足对更大的场景范围进行探测的需求。
然而，现有的TOF光学镜头大多采用玻璃透镜，玻璃的折射率较低，导致TOF光学镜头的视场角较小，光学传感器经由光学镜头接收的光线范围小，捕获场景信息少。且目前针对扩大光学镜头视场角的研究，大多集中在如何设计玻璃透镜组以扩大光学镜头的视场角，但采用复杂的玻璃透镜组将导致光学镜头体积、重量增大。因此，需要一种能够接收特定波段光，结构简单并且具有较大的视场角的光学镜头，以捕获更大角度的场景信息，满足对更大的场景范围进行探测的需求。
发明内容
为了解决上述问题，本公开通过在光学镜头中设置透镜，并在透镜后填充或形成折射率小于等于透镜的介质，从而扩大了接收特定波段光的光学镜头的视场角，能够捕获更大角度的场景信息，满足对更大的场景范围进行探测的需求。
本公开的实施例提供了一种光学镜头，其沿光线传输方向依次包括：透镜，被配置为对入射到其入光面的入射光线进行折射，所述入射光线被折射为折射光线，所述透镜的入光面位于所述透镜的第一侧，其中，所述入射光线为长波长的不可见光；以及介质，布置在所述透镜的第二侧，并且被配置为在所述透镜和所述介质的界面处对所述折射光线进行折射，其中，所述透镜的折射率大于等于所述介质的折射率，并且所述介质的折射率大于空气的折射率。
根据本公开实施例，所述透镜为正透镜，所述正透镜为菲涅尔透镜。
根据本公开实施例，所述透镜的第一侧为凸面和/或具有台阶结构，且所述透镜的第二侧为平面且与所述介质的第一侧贴合。
根据本公开实施例，所述透镜的折射率大于第一值。
根据本公开实施例，所述不可见光为波长大于1微米的光，所述透镜对所述不可见光的穿透率高于第二值。
根据本公开实施例，所述光学镜头的视场角大于第三值。
根据本公开实施例，所述第一值为3.5，所述第二值为55％，所述第三值为60度。
根据本公开实施例，所述透镜为以下任一种：硅透镜、锗透镜、磷化镓透镜、磷化铟透镜、硫化铅透镜。
根据本公开实施例，所述介质包括：第一介质和第二介质；所述第一介质位于所述透镜和所述第二介质之间，被配置为在所述透镜和所述第一介质的界面处对所述折射光线进行折射，所述折射光线被折射为第一透射光线并传播至所述第一介质和所述第二介质的界面处；以及所述第二介质位于所述第一介质远离所述透镜一侧，被配置为在所述第一介质和所述第二介质的界面处对所述第一透射光线进行折射，所述第一透射光线被折射为第二透射光线。
根据本公开实施例，所述第一介质的折射率大于所述第二介质的折射率，且所述第二介质的折射率大于等于空气的折射率。
根据本公开实施例，所述第一介质为固体介质，所述第二介质为固体、液体或气体介质。
根据本公开实施例，所述介质为固体、液体或气体介质。
根据本公开实施例，所述介质为油或水。
根据本公开实施例，所述光学镜头还包括：至少一个滤光层，其中，每个滤光层位于所述透镜和所述介质之间、或位于所述介质远离所述透镜的一侧、或位于所述透镜远离所述介质的一侧。
本公开的实施例还提供了一种光学感测系统，沿光线传输方向依次包括透镜、介质、以及光学传感器：所述透镜，被配置为对入射到其入光面的入射光线进行折射，所述入射光线被折射为折射光线，所述透镜的入光面位于所述透镜的第一侧，其中，所述入射光线为长波长的不可见光；所述介质，布置在所述透镜的第二侧，并且被配置为在所述透镜和所述介质的界面处对所述折射光线进行折射，折射后的光线在所述介质中传播，并在所述介质和所述光学传感器的界面处被折射为出射光线，所述透镜位于所述介质的第一侧；以及所述光学传感器，布置在所述介质的第二侧，被配置为接收所述出射光线，并且基于所述出射光线产生光学感测信号。
根据本公开实施例，所述透镜的折射率大于等于所述介质的折射率，并且所述介质的折射率大于空气的折射率。
根据本公开实施例，所述光学感测系统还包括：至少一个滤光层，其中，每个滤光层位于所述透镜和所述介质之间、或位于所述介质远离所述透镜的一侧、或位于所述透镜远离所述介质的一侧。
根据本公开实施例，在所述光学感测系统中，所述透镜与所述光学传感器共轴。
通过本公开的光学镜头和光学感测系统，能够扩大接收特定波段光的光学镜头的视场角，捕获更大角度的场景信息，满足对更大的场景范围进行探测的需求。
附图说明
为了更清楚地说明本公开的实施例的技术方案，下面将对实施例的描述中所需要使用的附图作简单的介绍。显而易见地，下面描述中的附图仅仅是本公开的一些示例性实施例，对于本领域普通技术人员来说，在不付出创造性劳动的前提下，还可以根据这些附图获得其它的附图。以下附图并未刻意按实际尺寸等比例缩放绘制，重点在于示出本发明的主旨。
图1A和图1B示出了根据本公开实施例的光学镜头结构的示意图；
图2A示出了根据本公开实施例的光学镜头中出射光线的出射位置的示意图；
图2B示出了根据本公开实施例的在光学镜头的介质的出光面处直接布置光学传感器时的成像位置的示意图；
图2C示出了光学镜头中不填充介质时成像位置的示意图；
图3示出了根据本公开实施例的光学镜头结构的另一示意图；
图4A和图4B示出了根据本公开实施例的光学感测系统的结构示意图；
图5A示出了根据本公开实施例的光学感测系统中成像位置的示意图；
图5B示出了光学感测系统中不填充介质时的成像位置的示意图；
图6示出了根据本公开实施例的光学感测系统的另一结构示意图；
图7示出了根据本公开实施例的光学感测系统的视场角扩大效果的示意图。
具体实施方式
为了使得本公开的目的、技术方案和优点更为明显，下面将参照附图详细描述根据本公开的示例实施例。显然，所描述的实施例仅仅是本公开的一部分实施例，而不是本公开的全部实施例，应理解，本公开不受这里描述的示例实施例的限制。
一般说来，术语“包括”与“包含”仅提示包括已明确标识的元素，而这些元素不构成一个排它性的罗列，设备也可能包含其他的元素。
在本说明书和附图中，具有基本上相同或相似元素用相同或相似的附图标记来表示，且对这些元素的重复描述将被省略。同时，在本公开的描述中，术语“第一”、“第二”等仅用于区分描述，而不能理解为指示或暗示相对重要性或排序。
此外，在在本说明书和附图中，所使用的“上”、“下”、“垂直”、“水平”等涉及方位或位置关系的术语仅用于方便描述根据本公开的实施例，而无意将本公开限制于此。因此不应理解为对本公开的限制。
此外，在本说明书和附图中，除非另有明确说明，“连接”或者“相连”等类似的词语并非限定于直接连接，也可以是间接连接；“界面”等类似的词语并非限定于直接形成界面， 也可以是通过另一媒介形成界面。
除非另有定义，本文所使用的所有的技术和科学术语与属于本公开的技术领域的技术人员通常理解的含义相同。本文中所使用的术语只是为了描述本发明实施例的目的，不是旨在限制本发明。
为便于描述本公开，以下介绍与本公开有关的概念。
飞行时间(Time Of Flight，TOF)探测技术采用主动光探测方式，向被测物体发射探测光波，光波遇到物体后反射回来，经光学镜头被光学传感器收集，光学传感器接收反射回的光波，并将接收的光波转换为光学感测信号，光学感测系统通过计算发射和接收光波的脉冲差或时间差，从而计算被测物体与光学传感器间的距离。光学感测信号可以用于生成场景的图像以支持多种应用，例如时差测距、深度感测、位置跟踪等。
根据本公开实施例，在光学感测系统中，以光学镜头的成像平面为顶点，以被测目标可通过光学镜头的最大范围的两条边缘构成的夹角，称为光学镜头的视场角(Field of view，FOV)，其决定了光学传感器能够成像的场景的角度范围，光学镜头的视场角越大，光学感测系统的视场角就越大，光学传感器能够接收更大范围内被物体反射回来的光线，成像的场景的角度范围更大，可以捕获到更多的场景信息。
综上所述，本公开的实施例提供的方案涉及飞行时间探测技术及视场角，下面将结合附图对本公开的实施例进行进一步地描述。
图1A和图1B示出了根据本公开实施例的光学镜头100结构的示意图。
如图1A所示，本公开的实施例提供了一种光学镜头100，沿光线传输方向依次包括透镜101和介质102。
所述透镜101被配置为对入射到其入光面的入射光线103进行折射，所述入射光线在所述入光面上的入射点A处发生折射并被折射为折射光线104，所述透镜的入光面位于所述透镜的第一侧，其中，所述入射光线103为长波长的不可见光，即，所述入射光线为波长长于可见光波长的不可见光。如图1A所示，所述透镜的第一侧为远离所述介质102的一侧，所述透镜的第二侧为靠近所述介质102的一侧。
所述介质102布置在所述透镜101的第二侧，并且被配置为在所述透镜101和所述介质102的界面(下文中称为第一界面)处对所述折射光线104进行折射。如图1A所示，所述介质102的第一侧靠近所述透镜101且作为所述介质102的入光面，所述透镜101的第二侧作为所述透镜101的出光面，所述介质102的第二侧远离所述透镜101且作为所述介质102的出光面。
应了解，所述折射光线104在所述第一界面上的点B处发生折射，折射后的光线在所述介质102中传播，并在所述介质102的出光面处的点C再次发生折射，并被折射为出射光线106。
根据本公开实施例，所述折射光线104在第一界面处被折射之后，折射后的光线在所述介质102中传播，在此传播期间，所述折射后的光线还可以被再次折射。例如，所述介 质202可以由多层介质构成，那么折射后的光线在所述介质202中传播期间，可以在多层介质的界面处多次发生折射。
根据本公开实施例，所述介质102可以为单层介质结构，或者可以包括第一介质和第二介质。在所述介质102为单层介质结构的情况下，如图1A所示，所述折射光线104在所述第一界面上的点B处发生折射并被折射为第一透射光线105，并且所述第一透射光线105在所述介质102的出光面处的点C被折射为出射光线106。
根据本公开实施例，所述透镜101的折射率大于等于所述介质102的折射率，并且所述介质102的折射率大于空气的折射率。应了解，所述介质102的折射率可以为等效折射率，例如在所述介质102为单层介质结构的情况下，所述介质102的折射率为所述单层介质的折射率；在所述介质102包括第一介质和第二介质的情况下，所述介质102的折射率为双层介质结构的等效折射率。所述等效折射率可以由第一介质的折射率和厚度、以及第二介质的折射率和厚度确定。
根据本公开实施例，所述透镜101的折射率大于第一值，所述第一值可以为2.5、3、3.5、4等，优选地所述第一值为3.5。根据本公开实施例，所述透镜可以是包含硅材料的硅透镜、包含锗材料的锗透镜、包含磷化镓材料的磷化镓透镜、包含磷化铟材料的磷化铟透镜、包含硫化铅材料的硫化铅透镜等。优选地，所述透镜是由硅材料制成的硅透镜。
根据本公开实施例，所述不可见光为波长大于1微米的光，所述透镜对所述不可见光的穿透率高于第二值。例如，所述不可见光的波长可以为1微米到6微米，并且所述第二值可以为50％-60％。优选地，所述第二值为55％。
根据本公开实施例，所述透镜101的折射率大于等于所述介质102的折射率，所述介质102的折射率大于空气的折射率，并且所述光学镜头100的视场角大于第三值。例如，所述第三值为60度到120度之间。优选地，所述第三值为60度。
例如，作为一个具体示例，在所述透镜101的折射率大于所述介质102的情况下，所述透镜101为硅透镜，入射光线103为红外光，其波长大于1微米，硅透镜在波长大于1微米的光波段具有很好的透光性能，硅透镜对于红外光的穿透率大于55％且对于可见光的穿透率很低，由此可以高效地透过红外光且同时有效地屏蔽可见光。例如，硅透镜的折射率约3.5，大于玻璃的折射率(约1.5)，采用玻璃透镜的光学镜头的视场角约为60度上的点B处再次发生折射，并被折射为第一透射光线105，根据折射定律，利用如下方程计算第一透射光线105的折射角：
Figure PCTCN2022104867-appb-000001
其中，θ s为折射光线104与第一界面上的点B处的法线的夹角，即，相当于所述折射光线104向介质102的入光面入射的入射角，θ c为第一透射光线105与第一界面上的点B处的法线的夹角，即第一透射光线105在点B处的折射角，n s为透镜101的折射率，n c为 介质102的折射率。如图2A所示，所述第一界面上的点B处的法线由通过点B的虚线示出。
根据勾股定理，利用如下方程计算所述第一界面上的点B至出射光线106在介质102的出光面上的出射位置(即点C)的横向距离H c：
Figure PCTCN2022104867-appb-000002
其中，d为介质102的厚度，θ θ为折射光线104在点B处向介质102的入光面入射的入射角，θ c为第一透射光线105在点B处的折射角，n s为透镜101的折射率，n c为介质102的折射率。
根据本公开实施例，所述介质102为固体、液体或气体介质。可选地，所述介质的厚度d大于所述透镜的厚度。
根据本公开实施例，介质102可以为玻璃、塑料、树脂、玻璃钢、气凝胶、水、油、醇、二氧化碳等材质，不同类型的介质102具有不同的折射率n c，且折射率n c均小于透镜101的折射率n s。
例如，当介质102为玻璃时，折射率n c约为1.5，透镜101折射率n s为3.5，介质厚度为d，可以计算图2A中所示的点B到点C之间的横向距离H c为
Figure PCTCN2022104867-appb-000003
如前所述，图2A中的出射光线106可以是进入另一介质进行传播，或可以直接照射到光学传感器上并由光学传感器进行感测。在该出射光线106直接照射到光学传感器上并由光学传感器进行感测的情况下，该出射光线106的传输长度非常短，甚至可以忽略。
根据本公开实施例，在透镜101的折射率等于所述介质102的折射率的情况下，θ c的大小与θ s相同，依照上述方程亦可计算出第一界面上的点B至出射光线106在介质102的出光面上的出射位置(即点C)的横向距离，且所述横向距离更小于图2A所示横向距离H c。
在图2B中示出了在介质102的出光面处直接布置光学传感器的情况下的成像位置的示意性图示。
如图2B所示，如图2A中所示的点C可以近似为入射光线103在光学传感器上的成像点，并且可以将所述介质102与所述光学传感器之间的界面称为第二界面，并且点C可以称为第二界面上的点C。此时该成像点C与入射光线103的入射点A之间的距离可以被表示为点A到点B之间的横向距离以及点B到点C之间的横向距离之和。可以理解，在透镜101的参数固定的情况下，点A到点B之间的横向距离也是固定的，那么成像点 C与入射点A之间的距离则直接由点B到点C之间的横向距离决定。
根据本公开实施例，通过在透镜101的下方布置介质102且该介质102的折射率大于空气的折射率，可以使得：与不布置介质102的光学镜头相比，点B到点C之间的横向距离减小，由此也减小了成像点C与入射点A之间的距离，由此在光学传感器尺寸固定的情况下，可以增大光学镜头100的视场角。
为了更清楚地展示本公开实施例的方案的效果，在图2C中示出了不布置介质102且与透镜101的出光面相距d的位置处布置光学传感器的情况下的成像位置的示意性图示。
如图2C所示，折射光线104在所述第一界面上的点B发生折射并被折射为第一透射光线105，第一透射光线105通过空气传播，并且在第二界面上的点C处照射到光学传感器上。类似地，利用上述公式也可以计算图2C中的点B到点C之间的横向距离H a为
Figure PCTCN2022104867-appb-000004
通过比较图2B和图2C、以及通过比较公式(3)和(4)，可以看出：在填充介质102且介质102的折射率大于空气折射率的情况下，点B至点C之间的横向距离H c小于不填充介质时的横向距离H a。
由此可见，在介质102的折射率n c大于空气的折射率1的情况下，随着n c的增大，横向距离H c逐渐减小。因此，当光学传感器的尺寸固定(例如1cm*1cm的方形或半径为1cm的圆形)、且透镜的参数不变以及透镜的出光面与光学传感器之间的距离(即d)不变时，在不填充介质102而直接提供空气层的情况下，假设光学镜头的视场角为60°，在填充介质102之后，由于介质102的折射率n c大于空气的折射率1，那么横向距离H c减小，即使得同一目标所形成的像减小，进而使得光学传感器可以对更大范围内的目标进行成像，即使得光学镜头的视场角大于60°。换言之，在光学传感器的尺寸固定的情况下，随着介质102的折射率n c的增大，光学镜头的视场角也增大。而且，在光学传感器的尺寸固定的情况下，通过适当设置透镜101的参数以及介质102的折射率n c，还可以减小介质102的厚度d，从而更有助于降低电子产品的厚度。
具体地，在透镜101的直径固定的情况下，介质102的折射率n c越大，第一界面上的点B至第二界面上的点C的横向距离H c越小，入射光线103经过光学镜头100后所成的像越小。那么，在光学传感器的尺寸固定的情况下，则光学镜头100能够接收的光线的角度范围越大，即入射光线103的入射角度可以更大。因此，通过在透镜101后填充介质102，可以增大光学镜头100的视场角。
返回图1B，对于图1B所示的透镜的第一侧具有台阶结构的情况，在介质102的出光面处直接布置光学传感器的情况下，也可以类似计算第一界面上的点B至第二界面上的点C的横向距离H c，并且同样地，在光学传感器的尺寸固定的情况下，随着介质102的 折射率n c的增大，光学镜头的视场角也增大。而且，在光学传感器的尺寸固定的情况下，通过适当设置透镜101的参数以及介质102的折射率n c，还可以减小介质102的厚度d，从而更有助于降低电子产品的厚度。
应了解，在图1A-图2B所示的光学镜头与光学传感器一起布置的情况下，可以在介质的出光面处直接布置光学传感器，也可以与介质间隔地布置光学传感器(即，在介质与光学传感器之间存在空气间隙)。在介质102与光学传感器之间存在空气间隙的情况下，由于空气的折射率小于介质102的折射率，在所述介质102的出光面处出射光线106会沿空气间隙传播，并使得在光学传感器上的成像位置相对于图2B的点C向左偏移一些，如图2C所示，从而使得所述光学镜头的视场角相较于不存在空气间隙的情况略为减小。因此，为保持光学镜头的视场角尽可能大，所述空气间隙的厚度(即介质102与光学传感器之间的距离)应较小。
图3示出了根据本公开实施例的光学镜头100结构的另一示意图。
如图3所示，根据本公开实施例，所述介质102包括第一介质1021和第二介质1022；所述第一介质1021位于所述透镜101和所述第二介质1022之间，被配置为在所述透镜101和所述第一介质1021的界面处对所述折射光线104进行折射，所述折射光线104被折射为所述第一透射光线105，并且所述第一透射光线105传播至所述第一介质1021和所述第二介质1022的界面(下文中称为第三界面)处；以及所述第二介质1022位于所述第一介质1021远离所述透镜101的一侧，被配置为在所述第三界面处对所述第一透射光线105进行折射，所述第一透射光线105被折射为第二折射光线107。
根据本公开实施例，所述第一介质1021的折射率大于所述第二介质1022的折射率，并且所述第二介质1022的折射率大于等于空气的折射率。
根据折射定律和勾股定理，图3中的第一界面上的点B(第一透射光线105从第一介质1021的入光面开始传播的点)到第三界面上的点D(第一透射光线105到达第一介质1021的出光面的点)之间的横向距离H c1为
Figure PCTCN2022104867-appb-000005
其中，d 1为第一介质1021的厚度，θ s为折射光线104向第一介质1021的入光面入射的入射角，n s为透镜101的折射率，n c1为第一介质1021的折射率。
根据折射定律和勾股定理，图3中的第三界面上的点D(第二透射光线107从第二介质1022的入光面开始传播的点)到第二界面上的点C(第二透射光线107到达第二介质1022的出光面的点)之间的横向距离H c2为
Figure PCTCN2022104867-appb-000006
其中，d 2为第二介质1022的厚度，θ s为折射光线104向第一介质1021的入光面入射的入射角，n s为透镜101的折射率，n c1为第一介质1021的折射率，n c2为第二介质1022的折射率。
则，第一界面上的点B至第二界面上的点C的横向距离H c为
Figure PCTCN2022104867-appb-000007
根据本公开实施例，所述第一介质1021为固体介质，所述第二介质1022为固体、液体或气体介质。
具体地，第一介质1021可以为玻璃、塑料、树脂、玻璃钢、气凝胶等材质，第二介质1022可以为玻璃、塑料、树脂、玻璃钢、气凝胶、水、油、醇、二氧化碳等材质。
可选地，可以通过调整第一介质1021的厚度d 1、第一介质1021的材质、第二介质1022的厚度d 2、第二介质1022的材质来改变如图3中所示的第一界面上的点B到第二界面上的点C的横向距离H c。在介质102的厚度d固定时，第一介质1021的厚度d 1越大，横向距离H c越小。
此外，如参照图2A和图2B所描述的，出射光线106可以是进入另一介质进行传播，或可以直接照射到光学传感器上并由光学传感器进行感测。在该出射光线106直接照射到光学传感器上并由光学传感器进行感测的情况下，该出射光线106的传输长度非常短，甚至可以忽略。尽管在图3中未明确示出光学传感器，应了解，在第二介质1022的下方可以布置有光学传感器，在第二介质1022与光学传感器之间形成了第二界面，如图3中所示的第二界面上的点C可以近似为入射光线103在光学传感器上的成像点。此外，可选地，还可以与第二介质1022间隔地布置光学传感器(即，在第二介质与光学传感器之间存在小的空气间隙)。
基于上述，本公开中，通过将介质分为第一介质和第二介质，可以通过调整第一介质和第二介质的厚度，调整光学镜头的视场角。
此外，根据本公开实施例，所述光学镜头还可以包括至少一个滤光层，每个滤光层可以被设置来滤除特定波长的光，使得光学传感器对红外光的检测更为准确。所述至少一个滤光层可以一起布置，或者可以分离地布置。每个滤光层可以位于所述透镜和所述介质之间、或可以位于所述介质远离所述透镜的一侧、或可以位于所述透镜远离所述介质的一侧。
应了解，在本公开实施例中描述的入射光线、折射光线、第一透射光线、第二透射光线和出射光线用于指代同一光线的不同传输阶段，以上术语仅用于对光线的不同传输阶段 进行区分，并不意图指示不同的光线。
图4A示出了根据本公开实施例的光学感测系统200的结构示意图。
如图4A所示，本公开的实施例提供了一种光学感测系统200，沿光线传输方向依次包括透镜201、介质202、以及光学传感器203。
所述透镜201被配置为对入射到其入光面的入射光线204进行折射，所述入射光线204在所述入光面上的入射点A处发生折射并被折射为折射光线205，所述透镜的入光面位于所述透镜201的第一侧，其中，所述入射光线204为长波长的不可见光，即，所述入射光线为波长长于可见光波长的不可见光。如图4A所示，所述透镜201的第一侧为远离所述介质202的一侧，所述透镜201的第二侧为靠近所述介质202的一侧。
所述介质202布置在所述透镜201的第二侧，并且被配置为在所述透镜201和所述介质202的界面(下文中称为第一界面)处对所述折射光线205进行折射，折射后的光线在所述介质202中传播，并在所述介质202和所述光学传感器203的界面(下文中称为第二界面)处被折射为出射光线207。如图4A所示，所述介质202的第一侧靠近所述透镜201且作为所述介质202的入光面，所述透镜201的第二侧作为所述透镜201的出光面，所述介质202的第二侧远离所述透镜201且作为所述介质202的出光面。
根据本公开实施例，所述折射光线205在第一界面处被折射之后，折射后的光线在所述介质202中传播，在此传播期间，所述折射后的光线还可以被再次折射。例如，所述介质202可以由多层介质构成，那么折射后的光线在所述介质202中传播期间，可以在多层介质的界面处多次发生折射。
根据本公开实施例，所述介质202可以为单层介质结构，或者可以包括第一介质和第二介质。在所述介质202为单层介质结构的情况下，如图4A所示，所述折射光线205在所述第一界面上的点B处发生折射并被折射为第一透射光线206，并且所述第一透射光线206在所述介质202和所述光学传感器203的界面(下文中称为第二界面)处被折射为出射光线207。
所述光学传感器203布置在所述介质202的第二侧，被配置为接收所述出射光线207，并且基于所述出射光线207产生光学感测信号。
根据本公开实施例，所述透镜201的折射率大于等于所述介质202的折射率，并且所述介质202的折射率大于空气的折射率。应了解，所述介质202的折射率为等效折射率，例如在所述介质202可以为单层介质结构的情况下，所述介质202的折射率为所述单层介质的折射率；在所述介质202包括第一介质和第二介质的情况下，所述介质202的折射率为双层介质结构的等效折射率。所述等效折射率可以由第一介质的折射率和厚度、以及第二介质的折射率和厚度确定。
根据本公开实施例，所述透镜201的折射率大于第一值，所述第一值可以为2.5、3、3.5、4等，优选地所述第一值为3.5。根据本公开实施例，所述透镜201可以是包含硅材料的硅透镜、包含锗材料的锗透镜、包含磷化镓材料的磷化镓透镜、包含磷化铟材料的磷 化铟透镜、包含硫化铅材料的硫化铅透镜等。优选地，所述透镜是由硅材料制成的硅透镜。
根据本公开实施例，所述不可见光为波长大于1微米的光，所述透镜201对所述不可见光的穿透率高于第二值。例如，所述不可见光的波长可以为1微米到6微米，并且所述第二值可以为50％-60％。优选地，所述第二值为55％。
根据本公开实施例，所述光学感测系统200的视场角大于第三值。例如，所述第三值为60度到120度之间。优选地，所述第三值为60度。
根据本公开实施例，所述透镜201为正透镜。可选地，所述透镜201可以是双凸正透镜、平凸正透镜或凹凸正透镜，且对光线有汇聚能力。优选地，所述透镜201的第一侧为凸面，第二侧为凸面、平面或凹面。
根据本公开实施例，所述透镜201可以为菲涅尔透镜，沿光线传输方向依次为菲涅尔透镜的纹理面和平面，即所述菲涅尔透镜的第一侧为纹理面，第二侧为平面。由于菲涅尔透镜更轻薄，因此可以避免出现光线边角变暗、模糊的现象。
根据本公开实施例，所述透镜201的第一侧为凸面和/或具有台阶结构，且所述透镜201的第二侧为平面且与所述介质202的第一侧贴合。例如，所述透镜201的第二侧与所述介质202的第一侧之间的贴合可以是直接贴合，或者通过粘接剂贴合。如图4B所示，其示出的光学感测系统中的透镜201’具有台阶结构。应了解，台阶结构的透镜201’相较于凸面的透镜201的生产工艺更为简单，更易制作，有利于降低生产成本。
根据本公开实施例，通过设置所述透镜和所述介质的折射率和厚度，使得所述光学感测系统200的视场角大于所述第三值。
根据本公开实施例，可选地，在所述透镜201、201’的入光面可镀有单层或多层增透膜，减少入射光线204的反射，增大所述透镜201、201’的透光率。
根据本公开实施例，所述透镜201与所述光学传感器203共轴，从透镜201入射的光线经过透射，可以在光学传感器203上成像。
基于上述，根据本公开实施例，通过在光学感测系统中沿着光线的传播方向依序包括具有大折射率的透镜和具有相对于透镜较小折射率的介质，长波长的入射光入射到所述透镜的入光面，沿着光线的传播方向，所述长波长的入射光依序被所述透镜的入光面、所述透镜与所述介质之间的界面、所述介质的出光面折射，最终被折射为出射光线，由此扩大了光学镜头对于所述长波光的入射光线的视场角。
应了解，可以参照图3所示地设置图4A和图4B中的介质202，即所述介质202可以包括第一介质和第二介质，其中所述第一介质位于所述透镜和所述第二介质之间，所述第二介质位于所述第一介质远离所述透镜一侧，所述第一介质的折射率大于所述第二介质的折射率，并且所述第二介质的折射率大于等于空气的折射率。
图5A示出了根据本公开实施例的光学感测系统200中的成像位置的示意图。图5B示出了光学感测系统200中不填充介质且与透镜的出光面相距d的位置处布置光学传感器的情况下的成像位置的示意性图示。在图5A和图5B中省略了出射光线207。
如图5A所示，入射光线204在透镜201的入光面上的点A处发生折射，并被折射为折射光线205，折射光线205在透镜201与介质202的界面(第一界面)处再次发生折射，并被折射为第一透射光线206，根据折射定律，可以类似地利用上述方程(1)计算第一透射光线206的折射角，并相应地利用上述方程(2)计算从图5A的点B到点C的横向距离。在介质202的下方直接布置光学传感器203的情况下，通过上述方程(2)可以直接计算出光学传感器203上的成像位置(即点C)与第一界面上的点B之间的距离H c，相应地可以确定出入射光线204的入射点A与成像位置点C之间的距离，由此可以确定光学感测系统200的视场角。
如图5B所示，在光学感测系统200中不填充介质的情况下，亦可类似地利用前文所述的各方程计算图5B的点B到点C的横向距离H a。通过比较图5A的距离H c和图5B的距离H a可理解到，在填充介质102且介质102的折射率大于空气折射率的情况下，点B至点C之间的横向距离小于不填充介质时的横向距离，使得同一目标所形成的像减小，进而使得光学感测系统200可以对更大范围内的目标进行成像，即使得光学感测系统200具有较大的视场角。
根据本公开实施例，所述介质202为固体、液体或气体介质。可选地，所述介质的厚度大于所述透镜的厚度。
根据本公开实施例，介质202可以为玻璃、塑料、树脂、玻璃钢、气凝胶、水、油、醇、二氧化碳等材质，不同类型的介质202具有不同的折射率n c，且折射率n c均小于透镜201的折射率n s。
如前文参照图2A和图2B所说明的，在介质202的折射率n c大于空气的折射率1且小于透镜的折射率n s的情况下，随着n c的增大，横向距离H c逐渐减小。换言之，在光学传感器的尺寸固定的情况下(例如1cm*1cm的方形或半径为1cm的圆形)，随着介质202的折射率n c的增大，光学感测系统的视场角也增大。而且，在光学传感器的尺寸固定的情况下，通过适当设置透镜201的参数以及介质202的折射率n c，还可以减小介质202的厚度d，从而更有助于降低光学感测系统200的厚度，乃至电子产品的厚度。
具体地，在透镜201的直径和光学传感器203的面积固定的情况下，介质202的折射率n c越大，折射光线205的入射位置(点B)至出射光线207的出射位置(点C)的横向距离H c越小，在光学传感器203上生成的图像越小。那么，在光学传感器的尺寸固定的情况下，光学感测系统200能够成像的场景角度范围越大。因此，通过在透镜201和光学传感器203之间填充介质202，可以增大光学感测系统200的视场角。
可选地，在保持光学感测系统200原有视场角不变的情况下，通过增大介质202的厚度d或减小介质202的折射率n c可以减小光学传感器203上成像的大小，从而减小光学传感器203的面积。
图6示出了根据本公开实施例的光学感测系统200的另一结构示意图。
如图6所示，根据本公开实施例，所述光学感测系统200包括透镜201、介质202和 光学传感器203，所述介质202包括第一介质2021和第二介质2022。
如图6所示，根据本公开实施例，所述第一介质2021位于所述透镜201和所述第二介质2022之间，被配置为在所述透镜201和所述第一介质2021的界面处对所述折射光线205进行折射，所述折射光线205被折射为所述第一透射光线206，并且所述第一透射光线206传播至所述第一介质2021和所述第二介质2022的界面(下文中称为第三界面)处；以及所述第二介质2022位于所述第一介质2021远离所述透镜201的一侧，被配置为在所述第三界面处对所述第一透射光线206进行折射，所述第一透射光线206被折射为第二透射光线208，并且所述第二透射光线208传播至所述第二介质2022和所述光学传感器203的界面(下文中称为第二界面)处。应了解，所述第二透射光线208在所述第二界面上的点C处发生折射，并被折射为出射光线207，所述出射光线207照射到所述光学传感器203上。在图6中省略了出射光线207。
根据本公开实施例，所述第一介质2021的折射率大于所述第二介质2022的折射率，并且所述第二介质2022的折射率大于等于空气的折射率。
在图6中还示出了第一界面上的点B(第一透射光线206从第一介质2021的入光面开始传播的点)到第三界面上的点D(第一透射光线206到达第一介质2021的出光面的点)的横向距离H c1。在图6中，d 1为第一介质2021的厚度，θ s为折射光线205向第一介质2021的入光面入射的入射角，n s为透镜201的折射率，n c1为第一介质2021的折射率。
此外，在图6中还示出了第三界面上的点D(第二透射光线208从第二介质2022的入光面开始传播的点)到第二界面上的点C(第二透射光线208到达第二介质2022的出光面的点)的横向距离H c2。在图6中，d 2为第二介质2022的厚度，n c2为第二介质2022的折射率。
类似地，可以利用上述方程(5)-(7)计算第一界面上的点B到第二界面上的点C的横向距离H c。根据本公开实施例，所述第一介质2021为固体介质，所述第二介质2022为固体、液体或气体介质。
具体地，第一介质2021可以为玻璃、塑料、树脂、玻璃钢、气凝胶等材质，第二介质2022可以为玻璃、塑料、树脂、玻璃钢、气凝胶、水、油、醇、二氧化碳等材质。
可选地，可以通过调整第一介质2021的厚度d 1、第一介质2021的材质、第二介质2022的厚度d 2、第二介质2022的材质来改变如图6所示的第一界面上的点B到第三界面上的点C的横向距离H c。在介质202的厚度d固定时，第一介质2021的厚度d 1越大，横向距离H c越小。
基于上述，本公开中，通过将介质分为第一介质和第二介质，可以通过调整第一介质和第二介质的厚度，调整光学感测系统的视场角。
应了解，可以在图6所示的第二介质下直接布置光学传感器，还可以与第二介质间隔地布置光学传感器(即，在第二介质与光学传感器之间存在小的空气间隙)。
此外，根据本公开实施例，所述光学感测系统还可以包括至少一个滤光层，每个滤光 层可以被设置来滤除特定波长的光，使得光学传感器对红外光的检测更为准确。所述至少一个滤光层可以一起布置，或者可以分离地布置。每个滤光层可以位于所述透镜和所述介质之间、或可以位于所述介质远离所述透镜的一侧、或可以位于所述透镜远离所述介质的一侧。
应了解，在本公开实施例中描述的入射光线、折射光线、第一透射光线、第二透射光线和出射光线用于指代同一光线的不同传输阶段，以上术语仅用于对光线的不同传输阶段进行区分，并不意图指示不同的光线。
图7示出了根据本公开实施例的光学感测系统的视场角相对于无介质填充的光学感测系统的视场角的扩大效果的示意图。
为了对比明显，在图7中采用实线示出了根据本公开实施例的光学感测系统的光线传输情况的示意图，图7中采用虚线示出了无介质填充的光学感测系统的光线传输情况的示意图。尽管在图7中示出了介质202，应了解对于虚线所示的无介质填充的光学感测系统而言，并不存在介质202，而介质202所在区域被空气填充。
如图7所示，虚线示出的入射光线经过透镜201的入光面进行折射，产生虚线示出的折射光线205，并经过透镜201的出光面再次折射，并在空气中产生虚线示出的第一透射光线206。其中，虚线示出的入射光线的入射角为α。
如图7所示，实线示出的入射光线204经过透镜201的入光面折射，产生实线示出的折射光线205，并经过透镜201的出光面再次折射，并在介质202中产生实线示出的第一透射光线206。其中，实线示出的入射光线的入射角为β，且β大于α。如图7所示，对于实线示出的入射光线的入射角为β的情况，此时的视场角为2γ。
因此，根据本公开的方案，光学感测系统通过采用透镜201和折射率大于空气的介质202，相对于传统的光学感测系统而言，增大了镜头系统的视场角。
通过本公开的光学镜头和光学感测系统，能够扩大接收特定波段光的光学镜头和光学感测系统的视场角，从而捕获更大角度的场景信息，满足对更大的场景范围进行探测的需求。
在上面详细描述的本公开的示例实施例仅仅是说明性的，而不是限制性的。本领域技术人员应该理解，在不脱离本公开的原理和精神的情况下，可对这些实施例或其特征进行各种修改和组合，这样的修改应落入本公开的范围内。

Claims (31)

  1. 一种光学镜头，沿光线传输方向依次包括：
    透镜，被配置为对入射到其入光面的入射光线进行折射，所述入射光线被折射为折射光线，所述透镜的入光面位于所述透镜的第一侧，其中，所述入射光线为长波长的不可见光；以及
    介质，布置在所述透镜的第二侧，并且被配置为在所述透镜和所述介质的界面处对所述折射光线进行折射，
    其中，所述透镜的折射率大于等于所述介质的折射率，并且所述介质的折射率大于空气的折射率。
  2. 根据权利要求1所述的光学镜头，其中，所述透镜为正透镜。
  3. 根据权利要求2所述的光学镜头，其中，所述正透镜为菲涅尔透镜。
  4. 根据权利要求1所述的光学镜头，其中，所述透镜的第一侧为凸面和/或具有台阶结构，且所述透镜的第二侧为平面且与所述介质的第一侧贴合。
  5. 根据权利要求1所述的光学镜头，其中，所述透镜的折射率大于第一值。
  6. 根据权利要求5所述的光学镜头，其中，所述不可见光为波长大于1微米的光，所述透镜对所述不可见光的穿透率高于第二值。
  7. 根据权利要求6所述的光学镜头，其中，所述光学镜头的视场角大于第三值。
  8. 根据权利要求7所述的光学镜头，其中，所述第一值为3.5，所述第二值为55％，所述第三值为60度。
  9. 根据权利要求5所述的光学镜头，其中，所述透镜为以下任一种：硅透镜、锗透镜、磷化镓透镜、磷化铟透镜、硫化铅透镜。
  10. 根据权利要求1所述的光学镜头，其中，所述介质包括：第一介质和第二介质；
    所述第一介质位于所述透镜和所述第二介质之间，被配置为在所述透镜和所述第一介质的界面处对所述折射光线进行折射，所述折射光线被折射为第一透射光线并传播至所述第一介质和所述第二介质的界面处；以及
    所述第二介质位于所述第一介质远离所述透镜一侧，被配置为在所述第一介质和所述第二介质的界面处对所述第一透射光线进行折射，所述第一透射光线被折射为第二透射光线。
  11. 根据权利要求10所述的光学镜头，其中，所述第一介质的折射率大于所述第二介质的折射率，且所述第二介质的折射率大于等于空气的折射率。
  12. 根据权利要求11所述的光学镜头，其中，所述第一介质为固体介质，所述第二介质为固体、液体或气体介质。
  13. 根据权利要求1所述的光学镜头，其中，所述介质为固体、液体或气体介质。
  14. 根据权利要求13所述的光学镜头，其中，所述介质为油或水。
  15. 根据权利要求1所述的光学镜头，还包括：至少一个滤光层，
    其中，每个滤光层位于所述透镜和所述介质之间、或位于所述介质远离所述透镜的一侧、或位于所述透镜远离所述介质的一侧。
  16. 一种光学感测系统，沿光线传输方向依次包括透镜、介质、以及光学传感器：
    所述透镜，被配置为对入射到其入光面的入射光线进行折射，所述入射光线被折射为折射光线，所述透镜的入光面位于所述透镜的第一侧，其中，所述入射光线为长波长的不可见光；
    所述介质，布置在所述透镜的第二侧，并且被配置为在所述透镜和所述介质的界面处对所述折射光线进行折射，折射后的光线在所述介质中传播，并在所述介质和所述光学传感器的界面处被折射为出射光线，所述透镜位于所述介质的第一侧；以及
    所述光学传感器，布置在所述介质的第二侧，被配置为接收所述出射光线，并且基于所述出射光线产生光学感测信号。
  17. 根据权利要求16所述的光学感测系统，其中，所述透镜为正透镜。
  18. 根据权利要求17所述的光学感测系统，其中，所述正透镜为菲涅尔透镜。
  19. 根据权利要求16所述的光学感测系统，其中，所述透镜的第一侧为凸面和/或具有台阶结构，且所述透镜的第二侧为平面且与所述介质的第一侧贴合。
  20. 根据权利要求16所述的光学感测系统，其中，所述透镜的折射率大于第一值。
  21. 根据权利要求20所述的光学感测系统，其中，所述不可见光为波长大于1微米的光，所述透镜对所述不可见光的穿透率高于第二值，所述光学传感器为红外光传感器。
  22. 根据权利要求21所述的光学感测系统，其中，所述光学镜头的视场角大于第三值。
  23. 根据权利要求22所述的光学感测系统，其中，所述第一值为3.5，所述第二值为55％，所述第三值为60度。
  24. 根据权利要求20所述的光学感测系统，其中，所述透镜为以下任一种：硅透镜、锗透镜、磷化镓透镜、磷化铟透镜、硫化铅透镜。
  25. 根据权利要求16所述的光学感测系统，其中，所述介质包括：第一介质和第二介质；
    所述第一介质位于所述透镜和所述第二介质之间，被配置为在所述透镜和所述第一介质的界面处对所述折射光线进行折射，所述折射光线被折射为第一透射光线并传播至所述第一介质和所述第二介质的界面处；以及
    所述第二介质位于所述第一介质和所述光学传感器之间，被配置为在所述第一介质和所述第二介质的界面处对所述第一透射光线进行折射，所述第一透射光线被折射为第二折射光线并传播至所述第二介质的出光面处，并且所述第二透射光线在所述第二介质的出光面处被折射为出射光线。
  26. 根据权利要求25所述的光学感测系统，其中，所述第一介质的折射率大于所述第二介质的折射率，且所述第二介质的折射率大于等于空气的折射率。
  27. 根据权利要求26所述的光学感测系统，其中，所述第一介质为固体介质，所述第二介质为固体、液体或气体介质。
  28. 根据权利要求16所述的光学感测系统，其中，所述介质为固体、液体或气体介质。
  29. 根据权利要求16所述的光学感测系统，其中，所述透镜的折射率大于等于所述介质的折射率，并且所述介质的折射率大于空气的折射率。
  30. 根据权利要求16所述的光学感测系统，还包括：至少一个滤光层，
    其中，每个滤光层位于所述透镜和所述介质之间、或位于所述介质远离所述透镜的一侧、或位于所述透镜远离所述介质的一侧。
  31. 根据权利要求16所述的光学感测系统，其中，所述透镜与所述光学传感器共轴。
PCT/CN2022/104867 2021-07-22 2022-07-11 光学镜头和光学感测系统 WO2023001005A1 (zh)

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