WO2023103314A1 - 探测单元、探测阵列、探测阵列母板、探测器和激光雷达 - Google Patents

探测单元、探测阵列、探测阵列母板、探测器和激光雷达 Download PDF

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Publication number
WO2023103314A1
WO2023103314A1 PCT/CN2022/098331 CN2022098331W WO2023103314A1 WO 2023103314 A1 WO2023103314 A1 WO 2023103314A1 CN 2022098331 W CN2022098331 W CN 2022098331W WO 2023103314 A1 WO2023103314 A1 WO 2023103314A1
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Prior art keywords
microlens
detection unit
photosensitive
array
detection
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PCT/CN2022/098331
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English (en)
French (fr)
Inventor
吴攸
向少卿
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上海禾赛科技有限公司
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Priority to EP22902752.9A priority Critical patent/EP4446768A1/en
Publication of WO2023103314A1 publication Critical patent/WO2023103314A1/zh

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    • 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
    • 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
    • G01S7/481—Constructional features, e.g. arrangements of optical elements
    • 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
    • G01S7/481—Constructional features, e.g. arrangements of optical elements
    • G01S7/4811—Constructional features, e.g. arrangements of optical elements common to transmitter and receiver
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A90/00—Technologies having an indirect contribution to adaptation to climate change
    • Y02A90/10—Information and communication technologies [ICT] supporting adaptation to climate change, e.g. for weather forecasting or climate simulation

Definitions

  • the invention relates to the field of light detection, in particular to a detection unit, a detection array, a detection array motherboard, a detector and a laser radar.
  • Lidar is a commonly used ranging sensor, which has the characteristics of long detection distance, high resolution, and low environmental interference. It is widely used in intelligent robots, drones, unmanned driving and other fields.
  • the working principle of lidar is to use the time it takes for the laser to go back and forth between the radar and the target, or the frequency shift caused by the frequency modulation continuous light going back and forth between the radar and the target to evaluate information such as the distance or speed of the target.
  • the distance measurement performance is an important technical indicator of lidar.
  • SiPM and SPAD single-photon detection devices
  • the area of the photosensitive area is much smaller than the pixel area, that is, the fill factor of the photosensitive area is small compared to the pixel area, and only the light signal incident on the photosensitive area will be effectively detected. This limits the detection efficiency of the photosensitive pixels.
  • a microlens array is usually arranged on the surface of the photosensitive pixel to focus the light on the photosensitive area.
  • the detection efficiency of the detection unit still needs to be improved.
  • the problem solved by the present invention is to provide a detection unit, a detection array, a detection array motherboard, a detector and a laser radar, so as to improve the detection efficiency of the detection unit.
  • the present invention provides a detection unit, comprising:
  • a photosensitive pixel the photosensitive pixel includes a plurality of photosensitive devices; a microlens array, the microlens array is located on the side where light is incident on the photosensitive pixel, and the microlens array includes a plurality of microlenses, the plurality of microlenses One-to-one correspondence with the plurality of photosensitive devices; the microlens includes a raised portion, and the material of the raised portion is an inorganic material.
  • the inorganic material is silicon.
  • the microlens array is formed on the surface of the photosensitive pixel.
  • the process of forming the microlens array includes: a deposition process.
  • the microlens is a planar microlens.
  • the microlens includes a plurality of protrusions, and the microlens is a diffractive lens.
  • the microlens is at least one of a Fresnel zone plate and a metasurface lens.
  • the microlens is suitable for converging the optical signal to the high electric field area of the corresponding photosensitive device.
  • the photosensitive device is a back-illuminated photosensitive device; the photosensitive device has a first surface provided with electrodes and a second surface opposite to the first surface; the microlens is located on the second surface side.
  • the reflective layer is located on the first surface of the photosensitive device.
  • the light signal is reflected on the first surface of the photosensitive device after sequentially transmitting through the microlens array and the photosensitive device.
  • the photosensitive device is a front-illuminated photosensitive device; the photosensitive device has a first surface provided with electrodes and a second surface opposite to the first surface; the microlens array is located on the first surface side.
  • the microlens further includes: a filling layer, the filling layer is located on the first surface of the photosensitive device.
  • the material of the filling layer is a low optical loss material.
  • the material of the filling layer is silicon oxide.
  • it further includes: a covering material, the covering material at least fills the gaps between adjacent protrusions, and the refractive index of the covering material is lower than that of the material of the protrusions.
  • the top surface of the covering material is higher than the top surface of the protrusion.
  • it further includes: an air gap, the air gap is located at least between adjacent protrusions.
  • it further includes: an encapsulation layer, the encapsulation layer is located at least on the microlens array.
  • the photosensitive device is a single photon detection device.
  • the microlens is suitable for converging the light signal to the depletion layer of the corresponding photosensitive device.
  • the present invention also provides a detection array, comprising: detection units arranged in an array, and the detection units are the detection units of the present invention.
  • the present invention also provides a detection array motherboard, comprising: a plurality of detection arrays, the detection arrays being the detection arrays of the present invention.
  • the present invention also provides a detector, including: at least one detection array, and the detected detection array is the detection array of the present invention.
  • the present invention also provides a laser radar, comprising: a light source, the light source is suitable for generating light; a detector, the detector is suitable for receiving echo light, and the detector is the detector of the present invention.
  • the material of the protruding part of the microlens for converging light is an inorganic material.
  • the difference between the refractive index of the material of the raised portion and the packaging material of the detection unit is relatively large, so it can be directly packaged on the surface of the microlens, that is, the packaging material can be combined with the surface of the microlens.
  • the microlens array is directly formed on the surface of the photosensitive pixel.
  • the microlens array is directly integrated with the photosensitive pixels, which can not only effectively improve the integration degree of the device and improve the stability of the device, but also reduce the later assembly steps and reduce the difficulty of assembly.
  • the microlens is a planar lens, that is, in the microlens, the surface heights of all the protrusions are consistent, and the surfaces through which the light transmits are all planes, and the surfaces through which the light transmits are not curved surfaces.
  • the surface of the lens facing the packaging material is parallel to the surface of the photosensitive pixel.
  • Fig. 1 is a schematic cross-sectional structure diagram of a detection unit
  • Fig. 2 is a schematic cross-sectional structure diagram of the first embodiment of the detection unit of the present invention
  • Fig. 3 is a schematic diagram of the optical path structure of a microlens converging light in the microlens array in the detection unit shown in Fig. 2;
  • Fig. 4 is the enlarged structure schematic diagram of microlens shown in Fig. 3;
  • Fig. 5 is a schematic diagram of the phase distribution of light when the microlens shown in Fig. 3 transmits light;
  • FIG. 6 is a schematic diagram of the phase distribution of the light rays transmitted by the microlens in the second embodiment of the detection unit of the present invention.
  • Fig. 7 is the relationship between the convex part and the transmission phase in the metasurface lens in the embodiment of the detection unit shown in Fig. 6;
  • Fig. 8 is a schematic cross-sectional structure diagram of the third embodiment of the detection unit of the present invention.
  • Fig. 9 is the focusing situation of the microlens for parallel incident rays in the detection unit embodiment shown in Fig. 8;
  • Fig. 10 is a schematic structural diagram of a fourth embodiment of the detection unit of the present invention.
  • Fig. 11 is the focusing situation of the microlens for parallel incident rays in the detection unit embodiment shown in Fig. 10;
  • Fig. 12 is the focusing situation of the microlenses for parallel incident light rays in the fifth embodiment of the detection unit of the present invention.
  • FIG. 1 a schematic cross-sectional structure diagram of a detection unit is shown.
  • the detection unit includes: a substrate 11; a photosensitive pixel 12, the photosensitive pixel 12 is located on the substrate 11, one side of the photosensitive pixel 12 and the substrate 11 are connected and fixed through a conductive silver glue 13, the The other side of the photosensitive pixel 12 is connected to the interconnection structure 14a in the substrate 11 through the connection line 14 ; the microlens array 15 is located on the photosensitive pixel 12 .
  • the photosensitive pixel 12 includes a plurality of photosensitive devices (not shown in the figure).
  • the photosensitive device is a single photon photosensitive device, such as a SPAD device array or a SiPM device.
  • the microlens array 15 includes a plurality of microlenses corresponding to the photosensitive devices one by one, and the microlenses are suitable for converging light signals to the photosensitive regions of the corresponding photosensitive devices.
  • the microlens array 15 is usually prepared by photoresist melting technology (that is, cube-shaped photoresist is melted to form a spherical shape), nanoimprinting technology and other methods. These preparation methods have low control precision on the shape and precision of the microlens, and the microlens array is also prone to the problem that the fill factor is lower than 100%, which causes the refraction effect of the microlens array to change, the optical performance is unstable, and it is difficult to The light signal is well converged to the photosensitive area of the photosensitive device, which causes the problem of low detection efficiency of the detection unit.
  • the microlens array cannot be completely filled, and the filling factor is lower than 100%, which will also cause unpredictable gaps in the microlens array and the detection unit, thereby causing reliability risks of the device.
  • the detection unit further includes: an encapsulation layer 16 covering the substrate 11 , the photosensitive pixels 12 and the microlens array.
  • the packaging solution with the best reliability and the lowest cost is the packaging solution based on organic materials, that is, the material of the packaging layer 16 is an organic material.
  • the material of the microlens array 15 prepared by the commonly used photoresist melting technology (that is, the cube-shaped photoresist is melted to form a spherical shape), nanoimprinting technology and other methods is usually also an organic material.
  • the refractive index of the material of the microlens array 15 is very close to the refractive index of the material of the encapsulation layer 16, if directly encapsulated, that is, the encapsulation layer 16 directly covers the surface of the microlens array 15, the The direct contact between the encapsulation layer 16 and the surface of the microlens array 15 will cause the refractive index of the materials on both sides of the interface between the microlens array 15 and the encapsulation layer 16 to be too close, thereby affecting or even eliminating the refraction effect of the microlens, so that The ability of microlenses to gather light is weakened or even failed.
  • an air gap 17 is arranged between the microlens array 15 and the encapsulation layer 16, that is, the surface of the encapsulation layer 16 and the microlens array 15 that have an optical effect is not In direct contact, under the encapsulation layer 16 , there is air above the microlens array 15 .
  • the air is greatly affected by the environment, and the existence of the air gap 17 will reduce the reliability of the device, and also put forward high requirements on the packaging process, increasing the complexity of the packaging process.
  • the existence of the air gap 17 is a big challenge to the vehicle certification.
  • the present invention provides a detection unit, comprising:
  • a photosensitive pixel the photosensitive pixel includes a plurality of photosensitive devices; a microlens array, the microlens array is located on the side where the light is incident on the photosensitive pixel, and the microlens array includes a plurality of microlenses, the microlens and There is one-to-one correspondence between the photosensitive devices; the microlens includes a raised portion, and the material of the raised portion is an inorganic material.
  • the material of the raised portion used to condense the light is an inorganic material.
  • the difference between the refractive index of the material of the raised portion and the packaging material of the detection unit is relatively large, so it can be directly packaged on the surface of the microlens, that is, the packaging material can be combined with the surface of the microlens In direct contact, there is no need to keep an air gap between the packaging material and the microlens, which can effectively improve the reliability of the device and reduce the difficulty of packaging; especially for automotive equipment, avoiding the formation of the air gap is conducive to passing the vehicle certification.
  • FIG. 2 shows a schematic cross-sectional structure diagram of an embodiment of the detection unit of the present invention.
  • the detection unit includes: a photosensitive pixel 110, the photosensitive pixel 110 includes a plurality of photosensitive devices (not shown in the figure); a microlens array 120, the microlens array 120 is located on the side where light is incident on the photosensitive pixel 110 , the microlens array 120 includes a plurality of microlenses 121, the microlenses 121 are in one-to-one correspondence with the photosensitive device; the microlenses 121 include a raised portion 122, and the material of the raised portion 122 is an inorganic material .
  • the material of the protruding portion 122 for converging light is inorganic material.
  • the refractive index of the material of the raised portion 122 and the refractive index of the packaging material of the detection unit, so the surface of the microlens 121 can be directly packaged without affecting its optical performance, that is, the The surface of the microlens 121 can be directly in contact with the packaging material without affecting the optical performance.
  • the formation of the gap is conducive to passing the vehicle certification.
  • the photosensitive pixels 110 are suitable for receiving light signals and photoelectrically converting the light signals.
  • the photosensitive pixel 110 includes a plurality of photosensitive devices arranged in an array.
  • the photosensitive device is a single photon detection device.
  • the photosensitive device includes: a SPAD device.
  • SPAD Single Photon Avalanche Diode
  • SPAD Single Photon Avalanche Diode
  • the application form as a photodetector is mainly a SPAD array or a silicon photomultiplier (Silicon photomultiplier, SiPM).
  • the photosensitive pixel 110 is located on the substrate 101, one side of the photosensitive pixel 110 is connected and fixed to the substrate 101 through a conductive silver glue 102, and the other side of the photosensitive pixel 110 is connected to the substrate 101.
  • the interconnection structures 103 in the substrate 101 are connected by connecting wires 104 .
  • the microlens array 120 is suitable for adjusting the light incident to the photosensitive pixels 110 .
  • the microlens array 120 includes a plurality of microlenses arranged in an array.
  • the plurality of microlenses correspond to the plurality of photosensitive devices one by one, that is, the microlenses are suitable for adjusting the light incident to the corresponding photosensitive devices.
  • the microlens includes a raised portion 122 .
  • the protruding portion 122 is suitable for converging light.
  • the material of the protruding portion 122 is an inorganic material.
  • the refractive index of the raised portion 122 is very different from that of the packaging material used in the later packaging process, so even if the raised portion 122 is in direct contact with the packaging material, its optical performance will not be affected, that is, it can be used in
  • the surface of the protruding portion 122 of the microlens 121 is directly encapsulated, without keeping an air gap.
  • the photosensitive device is a single photon detector, so the microlenses in the microlens array 120 are suitable for converging the transmitted optical signal to the depletion layer of the corresponding photosensitive device.
  • the area on the surface of the single photon detector suitable for transmitting light signals is the photosensitive surface, and electrodes, optical isolation structures and other components need to be prepared around the photosensitive surface, so the fill factor of the photosensitive surface of the photosensitive device compared to the total surface area of the photosensitive device is relatively small , but only the photons incident on the photosensitive region (that is, the depletion layer) through the photosensitive surface will be effectively detected by the photosensitive device. Therefore, the arrangement of the microlens can effectively increase the intensity of light incident on the depletion layer of the corresponding photosensitive device, so as to improve the detection efficiency of the single photon detector.
  • the inorganic material is silicon (with a refractive index of about 3.5).
  • silicon material to make the raised portion 122 can reduce light loss as much as possible through wavelength selection; and setting the material of the raised portion 122 to silicon can be compatible with the manufacturing process of the photosensitive pixel 110, and can be used in The photosensitive pixels 110 and the microlens array 120 are fabricated in the same process flow.
  • the microlens includes a base (not shown in the figure), the raised portion 122 is located on the surface of the base, and the base and the raised portion 122 are integrated structure. In other embodiments of the present invention, the microlens may only include the protrusion 122 .
  • the microlens array 120 is formed on the surface of the photosensitive pixel 110, the microlens array 120 is formed directly on the surface of the photosensitive pixel 110, and the microlens array 120 faces the photosensitive pixel 110.
  • the surface of the pixel 110 is in direct contact with the surface of the photosensitive pixel 110 facing the microlens array 120 .
  • the lens array is directly formed on the surface of the photosensitive pixel 110 .
  • the microlens array 120 is directly integrated with the photosensitive pixels 110, which not only can effectively improve device integration and improve device stability, but also reduce post-assembly steps and reduce assembly difficulty.
  • the detection unit further includes: a cladding material 123, the cladding material 123 at least fills the gap between adjacent protrusions 122, and the refractive index of the cladding material 123 is lower than The refractive index of the material of the protruding portion 122 .
  • the covering material 123 is filled between the protrusions 122 to enhance protection.
  • the refractive index of the cladding material 123 is lower than that of the material of the protrusion 122 , for example, the cladding material 123 may be a polymer or a silicon compound.
  • the top surface of the covering material 123 is higher than the top surface of the protrusion 122 . Making the top surface of the covering material 123 higher than the top surface of the raised portion 122 can make the covering material 123 completely cover the raised portion 122, thereby effectively protecting the raised portion for subsequent encapsulation.
  • the detection unit further includes: an encapsulation layer 130 , and the encapsulation layer is at least located on the microlens array 120 .
  • the encapsulation layer is suitable for protecting the detection unit.
  • the top surface of the coating layer material filled between the protrusions is higher than the top surface of the protrusions 122, so the encapsulation layer is in direct contact with the coating material 123, That is, the encapsulation is directly performed on the surface of the cladding material 123 .
  • the encapsulating material when the covering material 123 exposes the raised portion 122 or the detection unit does not include the encapsulation layer, the encapsulating material is in direct contact with the surface of the raised portion, That is, it is directly packaged on the surface of the microlens array 120 .
  • the process of forming the microlens array 120 includes: a deposition process. Specifically, the process of forming the microlens array 120 includes: depositing a lens material layer on the surface of the photosensitive pixel 110; forming a patterned layer on the surface of the lens material layer, and the patterned layer exposes the lens material layer the region to be etched; using the patterned layer as a mask, etch the microlens material layer to form the microlens array 120 with the raised portion.
  • the cladding material 123 is also filled between the adjacent protruding parts 122 , so after forming the microlens array 120 by etching, the method further includes: filling the cladding material 123 between the adjacent protruding parts.
  • the microlens is a planar microlens, that is, in the microlens, the surface heights of all the protrusions are consistent, and the surfaces through which the light transmits are all planes, and the surfaces through which the light transmits Surfaces are not curved.
  • the surface of the microlens facing the packaging material is parallel to the surface of the photosensitive pixel 110 .
  • the microlens includes: a plurality of raised parts 122, and the said microlens is a diffractive lens, that is, light diffracts during the projection of the plurality of raised parts 122 to achieve Convergence effect.
  • the microlens is a diffractive lens, and the microlens does not need to rely on the refraction effect produced by the difference in refractive index of the surface, so whether the surface of the microlens is air or a packaging material with a different refractive index, its diffraction effect will not be affected, that is The optical performance of the microlens is not affected by the material in contact with it, and can directly contact with the encapsulation material.
  • FIG. 3 shows a schematic view of the optical path structure of a microlens in the microlens array 120 in the detection unit shown in FIG. 2, and
  • FIG. 4 shows an enlarged structure of the microlens shown in FIG. 3
  • FIG. 5 shows a schematic diagram of the phase distribution of light rays when the microlens shown in FIG. 3 transmits light rays.
  • the microlens 121 is a Fresnel Zone Plate (Binary Fresnel Zone Plate, FZP).
  • a Fresnel zone plate is composed of a series of raised rings of different radii and widths.
  • the microlens is a Fresnel zone plate, in a plane parallel to the surface of the photosensitive pixel 110, the cross-section of the raised portion 122 is circular, and the plurality of raised portions 122 are concentric. Circular distribution (as shown in the small diagram 501 in FIG. 5 ).
  • the horizontal axis represents the section radius of the protrusion 122
  • the vertical axis represents the phase.
  • Line 502 represents the microlens surface profile.
  • the phase difference between the top surface 122a of the raised portion 122 and the surface 124a of the base 124 between the raised portions 122 is ⁇ , that is, the difference between the top surface of the ring and the bottom surface of the gap between the rings. The phase difference between them is ⁇ .
  • phase difference between the top surface 122a of the raised portion 122 and the surface 124a of the base 124 between the raised portion 122 satisfies preset Require.
  • the relationship between the phase difference between the top surface 122a of the raised portion 122 and the surface 124a of the base 124 between the raised portion 122 and the height h of the raised portion 122 above the base 124 is:
  • n is the refractive index of the material of the raised portion 122
  • n 0 is the refractive index of the material of the gap between the raised portions 122
  • ⁇ is the wavelength of the transmitted light.
  • the radius of the raised portion 122 is:
  • n is the refractive index of the material (such as the substrate 124 ) under the protrusion
  • k is the order of the ring.
  • the radius R2 in Figure 4 represents the second-order circle in the raised portion
  • the specific sizes of the radius R1 and the radius R2 can be obtained according to the above formula of R k .
  • FIG. 6 shows a schematic diagram of phase distribution of light rays transmitted by microlenses in another embodiment of the detection unit of the present invention.
  • the microlens may also be a metasurface lens (Metalens).
  • the metasurface lens is composed of periodically arranged structural units with different cross-sectional sizes. Each structural unit corresponds to a different phase change, and the corresponding structural units are set at different positions according to the target spatial phase distribution.
  • the structural unit is a cylinder or a cuboid. Therefore, when the microlens is a metasurface lens, in a plane parallel to the surface of the photosensitive pixel, the cross-section of the raised portion 222 is circular or rectangular, and the cross-sectional dimensions of the plurality of raised portions 222 are different from each other. same. Moreover, the plurality of protrusions 222 are distributed in a plane parallel to the surface of the photosensitive pixel according to a preset rule (as shown in the small diagram 601 in FIG. 6 ).
  • the structural unit protruding part 222
  • the horizontal axis represents the distance between the center of the protruding part 222 and the center of the microlens
  • the vertical axis represents the phase.
  • Line 602 represents the phase of different positions of the microlens.
  • the distance between the center of the raised portion 222 and the center of the microlens is represented by r, and the phase at r is:
  • Each of the protrusions 222 will cause a phase delay, which can be calculated based on the waveguide model as follows:
  • ⁇ is the wavelength of the transmitted light
  • n eff is the effective refractive index of the fundamental mode transmitted in the raised portion 222
  • H is the height of the raised portion 222 .
  • each of the raised portions 222 is the same, and the phase delay caused by each raised portion 222 is mainly related to the cross-sectional size of the raised portion 222 (that is, the cross-sectional size of the raised portion 222 affects neff ).
  • FIG. 7 the relationship between the convex portion and the transmission phase in the metasurface lens in the embodiment of the detection unit shown in FIG. 6 is shown.
  • the convex portion 222 of the microlens is a cylinder, and the horizontal axis in FIG. Model calculation results.
  • the actual design can be based on simulation results or theoretical calculations based on the above formulas. Or, take the simulation results as a benchmark and the calculation results of the waveguide model as a reference.
  • the microlenses in some embodiments of the present invention are diffractive lenses, and the structural size of the microlenses is related to the wavelength of the transmitted light. According to the light wavelength (working wavelength) that the photosensitive device needs to sense, the structural size of the microlens can be obtained, which can make the microlens have the best focusing effect on the incident light of the working wavelength, and the interfering light other than the working wavelength cannot be effectively focused, so that it can Reduce the impact of interfering light on sensing devices.
  • the size of the raised portion 222 is related to the phase delay required by the position of the raised portion 222 , so based on the preset focal length f and distance r, the calculation of different positions of the raised portion 222 required phase difference, and then obtain the cross-sectional dimension of the protrusion 222 based on the phase difference.
  • the detection unit further includes: an air gap, and the air gap is at least located between adjacent protrusions 222 .
  • the refractive index of air is very low, and an air gap is reserved between adjacent raised portions 222. While enlarging the refractive index difference between the raised portions 222 and the surrounding environment to ensure good optical performance, the process difficulty is not high. low impact.
  • the focal length of the microlens is greater than the distance from the surface of the photosensitive device to the depletion layer.
  • the distance is the vertical distance from the depletion layer to the surface of the photosensitive device.
  • Increasing the focal length of the microlens and reducing its numerical aperture while maintaining the same aperture will help reduce processing difficulty and improve the processing accuracy and focusing effect of the microlens.
  • the focal length of the microlens of the present invention is relatively large, and can be applied to back-illuminated photosensitive devices and front-illuminated photosensitive devices.
  • FIG. 8 shows a schematic cross-sectional structure diagram of another embodiment of the detection unit of the present invention.
  • the microlens 812 is suitable for converging the optical signal to the high electric field region 813 of the corresponding photosensitive device 811, that is, the focal length of the microlens 812 satisfies a preset condition, so that the light The high electric field region 813 of the corresponding photosensitive device 811 is converged.
  • the photosensitive device 811 is a back side illumination (BSI) photosensitive device 811, that is to say, the electrode 814 of the photosensitive device 811 is located on one side, and the light Incident from the other side of the photosensitive device 811.
  • the high electric field region 813 is located in the depletion layer of the photosensitive device 811 .
  • the photosensitive device 811 has a first surface 811a on which electrodes 814 are disposed and a second surface 811b opposite to the first surface 811a; the microlens array is located on one side of the second surface 811b. Therefore, the photosensitive device 811 includes an epitaxial layer 815, and the epitaxial layer 815 is suitable for absorbing photons to realize detection; an electrode 814, and the electrode 814 is located on the surface of the epitaxial layer 815; the microlens 812 is located on the surface of the epitaxial layer 815 The surface of the epitaxial layer 815 on the side away from the electrode 814 .
  • the light signal enters the epitaxial layer 815 after being transmitted through the microlens 812 , and the microlens 812 converges the transmitted light to the high electric field region 813 in the epitaxial layer 815 .
  • the optical signal is reflected on the first surface 811 a of the photosensitive device 811 after being transmitted through the microlens array and the photosensitive device 811 in sequence.
  • part of the optical signal is absorbed by the epitaxial layer 815 to realize detection; part of the light is transmitted through the surface of the epitaxial layer 815 on which the electrode 814 is set and reflected, and is incident on the epitaxial layer 815 again.
  • Epitaxial layer 815 to increase the probability of absorption detection.
  • the detection unit further includes: a reflective layer 816 located on the first surface 811 a of the photosensitive device 811 .
  • the reflective layer 816 is adapted to increase the probability of light passing through the photosensitive device 811 being reflected on the first surface 811 a of the photosensitive device 811 .
  • the microlens 812 usually has a large aperture and a short focal length, so generally speaking, the microlens 812 in the microlens array usually has a larger numerical aperture (NA).
  • NA numerical aperture
  • the focal length of the microlens 812 makes the incident light reflect by the electrode 814 or the reflective layer 816 and then focus on the focal point, so that the aperture can be increased while keeping the aperture constant.
  • the numerical aperture of the microlens 812 can be effectively reduced, thereby reducing the processing difficulty of the microlens 812 .
  • the microlens 812 is a metasurface lens, the reduction in numerical aperture can also effectively improve the transmittance and focusing effect of the microlens 812 .
  • FIG. 9 it shows the focusing of parallel incident light by the microlens 812 in the embodiment of the detection unit shown in FIG. 8 .
  • the microlens 812 in the microlens array is a metasurface lens.
  • the horizontal axis represents the distance between the center of the protrusion and the center of the microlens 812
  • the vertical axis represents the distance from the incident surface of the photosensitive device 811 .
  • the region corresponding to the metasurface lens and between the dashed line 902 and the dashed line 903 is the region corresponding to the dielectric layer covering the epitaxial layer 815 in the photosensitive device 811 (the The dielectric layer can play the role of isolation protection and anti-reflection, the material of the dielectric layer includes at least one of silicon oxide and silicon nitride), between the dotted line 903 and the dotted line 904 is the epitaxial layer 815 of the photosensitive device 811 For the corresponding area, the area between the dotted line 904 and the horizontal axis is the area corresponding to the electrode 814 .
  • the combination of the back-illuminated photosensitive device 811, the electrode 814, and the reflective layer 816 can effectively extend the focal length of the microlens 812, so that the light is reflected by the electrode 814 and the reflective layer 816 and converges to the photosensitive element.
  • the microlens 812 can effectively focus light.
  • the focal length of the microlens 812 should be the thickness of the epitaxial layer 815 of the photosensitive device 811 and the surface of the reflective layer 816 to the high electric field region The sum of the distances between 813.
  • FIG. 10 a schematic structural diagram of another embodiment of the detection unit of the present invention is shown.
  • the photosensitive device 1011 is a front side illumination (FSI) photosensitive device, that is, light is incident from the side of the photosensitive device 1011 where the electrode 1014 is disposed.
  • FSI front side illumination
  • the photosensitive device 1011 has a first surface 1011a on which electrodes 1014 are disposed and a second surface 1011b opposite to the first surface 1011a; the microlens array is located on one side of the first surface 1011a. Therefore, the electrode 1014 of the photosensitive device 1011 and the microlens array are sequentially stacked on one side surface of the epitaxial layer of the photosensitive device 1011 .
  • the light signal enters the epitaxial layer after being transmitted through the microlens 1012, and the microlens 1012 converges the transmitted light to the high electric field region 1013 in the epitaxial layer.
  • the high electric field region 1013 is located in the depletion layer of the photosensitive device 1011 .
  • the photosensitive device 1011 has two electrodes, one electrode 1014 is located on the first surface 1011 a, and the other electrode 1014 is located on the second surface 1011 b.
  • the microlens 1012 further includes: a filling layer 1016 , and the filling layer 1016 is located on the first surface 1011 a of the photosensitive device 1011 .
  • the filling layer 1016 is suitable for increasing the distance between the microlens 1012 and the high electric field region 1013 of the corresponding photosensitive device 1011, so as to increase the focal length and reduce the numerical aperture; The light avoids the electrodes to improve detection efficiency.
  • the material of the filling layer 1016 is a low optical loss material.
  • the filling layer 1016 is made of a low light loss material, which can effectively reduce the loss when the light transmits through the filling layer 1016, and can effectively improve the detection efficiency.
  • the material of the filling layer 1016 may be silicon oxide.
  • the silicon oxide material is highly compatible with the manufacturing process of the photosensitive device 1011 and the microlens array, and can effectively reduce the impact of the filling layer 1016 being set.
  • the thickness of the filling layer 1016 is determined according to the numerical aperture of the microlens 1012 and process constraints, that is, the numerical aperture of the microlens 1012 is designed based on process constraints to determine the shortest focal length f, and then determined according to the focal length f
  • the thickness of the filling layer 1016 that is, the focal length f minus the distance from the surface of the photosensitive device 1011 to the high electric field area is the thickness of the filling layer 1016 .
  • FIG. 11 it shows the focusing situation of the microlens 1012 in the embodiment of the detection unit shown in FIG. 10 for parallel incident light rays.
  • the microlenses 1012 in the microlens array are metasurface lenses.
  • the horizontal axis represents the distance between the center of the protrusion and the center of the microlens 1012
  • the vertical axis represents the distance from the surface of the photosensitive device 1011 where light is incident.
  • Between the dotted line 1101 and the dotted line 1102 in Fig. 11 is the area corresponding to the metasurface lens
  • between the dotted line 1102 and the dotted line 1103 is the area corresponding to the filling layer 1016
  • between the dotted line 1103 and the horizontal axis is the photosensitive device The area corresponding to the epitaxial layer of 1011.
  • the light transmits through the metasurface lens and the filling layer 1016, it is focused on the epitaxial layer of the photosensitive device 1011, and is near the high electric field region of the PN junction formed in the epitaxial layer, thus It can ensure that the optical signal is concentrated in the high electric field region, and can effectively increase the probability that the optical signal is absorbed and excites carriers, thereby causing an avalanche effect, and can effectively improve the effective detection of the optical signal.
  • the microlenses are metasurface microlenses.
  • the metasurface lens has a higher focusing efficiency and can improve the detection efficiency more effectively.
  • the combination of metasurface microlenses with back-illuminated photosensitive devices, or the combination of metasurface microlenses with front-illuminated photosensitive devices is just an example.
  • the microlens combined with the back-illuminated photosensitive device or the microlens combined with the front-illuminated photosensitive device may also be a Fresnel zone plate.
  • FIG. 12 it shows the focusing situation of the microlenses for parallel incident light rays in still another embodiment of the detection unit of the present invention.
  • the microlens in the microlens array is a Fresnel zone plate; and the photosensitive device is a positive photosensitive device, and the microlens and the photosensitive device Filling layers are also arranged between them.
  • the horizontal axis represents the radius of the raised portion
  • the vertical axis represents the distance from the light-incident surface of the photosensitive device.
  • Between the dotted line 1201 and the dotted line 1202 in Fig. 12 is the area corresponding to the Fresnel zone plate
  • Between the dotted line 1202 and the dotted line 1203 is the area corresponding to the filling layer
  • between the dotted line 1203 and the horizontal axis is the area corresponding to the Fresnel zone plate.
  • the Fresnel zone plate can also focus the incident light in the middle and high electric field region.
  • the Fresnel zone plate is larger in size and less difficult to process, which can effectively improve the yield rate.
  • the present invention also provides a detection array, which specifically includes: detection units arranged in an array, and the detection units are the detection units of the present invention.
  • the detection unit is the detection unit of the present invention, so for the specific technical solution of the detection unit, refer to the foregoing embodiments of the detection unit, and the present invention will not repeat them here.
  • the material of the protruding part of the microlens in the detection unit used to condense the light is an inorganic material.
  • the difference between the refractive index of the material of the raised portion and the packaging material of the detection unit is relatively large, so it can be directly packaged on the surface of the microlens, that is, the packaging material can be combined with the surface of the microlens Contact can effectively improve the reliability of the device and reduce the difficulty of packaging without retaining an air gap between the packaging material and the microlens. Especially for vehicle-mounted equipment, avoiding the formation of air gaps is conducive to passing vehicle certification.
  • the present invention also provides a detection array motherboard, which specifically includes: a plurality of detection arrays, and the detection arrays are the detection arrays of the present invention.
  • the detection array is the detection array of the present invention, so the specific technical solution of the detection array refers to the description of the detection array above, and the present invention will not repeat it here.
  • the present invention also provides a detector, including: at least one detection array, and the detection array is the detection array of the present invention.
  • the detection array is the detection array of the present invention, so the specific technical solution of the detection array refers to the description of the detection array above, and the present invention will not repeat it here.
  • the material of the protruding part of the microlens in the detection unit in the detection array used to condense the light is an inorganic material.
  • the difference between the refractive index of the material of the raised portion and the packaging material of the detection unit is relatively large, so it can be directly packaged on the surface of the microlens, that is, the packaging material can be combined with the surface of the microlens Contact can effectively improve the reliability of the device and reduce the difficulty of packaging without retaining an air gap between the packaging material and the microlens. Especially for vehicle-mounted equipment, avoiding the formation of air gaps is conducive to passing vehicle certification.
  • the packaging of the detection array in the detector does not need to retain an air gap, the packaging difficulty is low, and the reliability is high, and the detector is more in line with the vehicle certification.
  • the present invention also provides a laser radar, which includes: a light source, the light source is suitable for generating light; a detector, the detector is suitable for receiving echo light, and the detector is the detector of the present invention .
  • the material of the raised portion of the microlens for converging light is an inorganic material.
  • the difference between the refractive index of the material of the raised portion and the packaging material of the detection unit is relatively large, so it can be directly packaged on the surface of the microlens, that is, the packaging material can be combined with the surface of the microlens Contact can effectively improve the reliability of the device and reduce the difficulty of packaging without retaining an air gap between the packaging material and the microlens.
  • avoiding the formation of air gaps is conducive to passing vehicle certification.
  • microlens array is directly formed on the surface of the photosensitive pixel.
  • the microlens array is directly integrated with the photosensitive pixels, which can not only effectively improve the integration degree of the device and improve the stability of the device, but also reduce the later assembly steps and reduce the difficulty of assembly.
  • the microlens is a planar lens, that is, in the microlens, the surface heights of all the protrusions are consistent, and the surfaces through which the light is transmitted are all planes, and the surfaces through which the light is transmitted are not curved surfaces.
  • the surface is parallel to the surface of the photosensitive pixel.

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Abstract

一种探测单元、探测阵列、探测阵列母板、探测器和激光雷达，所述探测单元包括：感光像素，所述感光像素包括多个感光器件；微透镜阵列，所述微透镜阵列位于光入射所述感光像素的一侧，所述微透镜阵列包括多个微透镜，所述多个微透镜与所述多个感光器件一一对应；所述微透镜包括凸起部，所述凸起部的材料为无机材料。所述封装材料能够与所述微透镜表面接触，能够有效封装材料和微透镜之间无需保留空气隙，能够有效提高器件可靠性，降低封装难度；特别是针对车载设备，避免空气隙的形成有利于通过车规认证。

Description

探测单元、探测阵列、探测阵列母板、探测器和激光雷达
本申请要求2021年12月9日提交中国专利局、申请号为2021115033332、发明名称为“探测单元、探测阵列、探测阵列母板、探测器和激光雷达”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本发明涉及光探测领域，特别涉及一种探测单元、探测阵列、探测阵列母板、探测器和激光雷达。
背景技术
激光雷达是一种常用的测距传感器，具有探测距离远、分辨率高、受环境干扰小等特点，广泛应用于智能机器人、无人机、无人驾驶等领域。激光雷达的工作原理是利用激光往返于雷达和目标之间所用的时间，或者调频连续光在雷达和目标之间往返所产生的频移来评估目标的距离或速度等信息。
测远性能是激光雷达的一项重要技术指标。随着SiPM、SPAD等单光子探测器件引入激光雷达，由于其更强的光子探测能力、更高的灵敏度、更低的电子噪声，使其越来越受到业内人士的青睐。
采用SiPM、SPAD等单光子探测器件的感光像素中，感光区域的面积相比于像素面积小很多，即感光区域面积相比于像素面积的填充因子很小，而只有入射到感光区域的光信号才会被有效探测。这就限制了感光像素的探测效率。为了提升探测效率，通常会在感光像素表面设置微透镜阵列，将光聚焦在感光区域。
但是即使设置微透镜阵列，探测单元的探测效率依旧有待提高。
发明内容
本发明解决的问题是提供一种探测单元、探测阵列、探测阵列母 板、探测器和激光雷达，以提高探测单元的探测效率。
为解决上述问题，本发明提供一种探测单元，包括：
感光像素，所述感光像素包括多个感光器件；微透镜阵列，所述微透镜阵列位于光入射所述感光像素的一侧，所述微透镜阵列包括多个微透镜，所述多个微透镜与所述多个感光器件一一对应；所述微透镜包括凸起部，所述凸起部的材料为无机材料。
可选的，所述无机材料为硅。
可选的，所述微透镜阵列形成于所述感光像素的表面。
可选的，形成所述微透镜阵列的过程包括：沉积工艺。
可选的，所述微透镜为平面型微透镜。
可选的，所述微透镜包括多个凸起部，所述微透镜为衍射型透镜。
可选的，所述微透镜为菲涅尔波带片和超表面透镜中的至少一种。
可选的，所述微透镜适宜于将光信号会聚至所对应感光器件的高电场区域。
可选的，所述感光器件为背照式感光器件；所述感光器件具有设置电极的第一面以及与所述第一面相背的第二面；所述微透镜位于所述第二面的一侧。
可选的，还包括：反射层，所述反射层位于所述感光器件的第一面。
可选的，光信号依次透射所述微透镜阵列和所述感光器件后，在所述感光器件的第一面反射。
可选的，所述感光器件为正照式感光器件；所述感光器件具有设置电极的第一面以及与所述第一面相背的第二面；所述微透镜阵列位于所述第一面的一侧。
可选的，所述微透镜还包括：填充层，所述填充层位于所述感光 器件的第一面上。
可选的，所述填充层的材料为低光损耗材料。
可选的，所述填充层的材料为氧化硅。
可选的，还包括：包覆材料，所述包覆材料至少填充于相邻凸起部之间的空隙，所述包覆材料的折射率低于所述凸起部的材料的折射率。
可选的，所述包覆材料的顶部表面高于所述凸起部的顶部表面。
可选的，还包括：空气隙，所述空气隙至少位于相邻凸起部之间。
可选的，还包括：封装层，所述封装层至少位于所述微透镜阵列上。
可选的，所述感光器件为单光子探测器件。
可选的，所述微透镜适宜于将光信号会聚至所对应感光器件的耗尽层。
相应的，本发明还提供一种探测阵列，包括：呈阵列排布的探测单元，所述探测单元为本发明的探测单元。
本发明还提供一种探测阵列母板，包括：多个探测阵列，所述探测阵列为本发明的探测阵列。
本发明还提供一种探测器，包括：至少一个探测阵列，所搜探测阵列为本发明的探测阵列。
本发明还提供一种激光雷达，包括：光源，所诉光源适宜于产生光线；探测器，所述探测器适宜于接收回波光，所述探测器为本发明的探测器。
与现有技术相比，本发明的技术方案具有以下优点：
本发明技术方案中，所述微透镜用以会聚光线的凸起部的材料为无机材料。所述凸起部的材料的折射率与所述探测单元的封装材料的 折射率之间差异较大，因此能够在所述微透镜表面直接封装，即所述封装材料能够与所述微透镜表面接触，封装材料和微透镜之间无需保留空气隙，能够有效提高器件可靠性，降低封装难度；特别是针对车载设备，避免空气隙的形成有利于通过车规认证。
本发明可选方案中，所述微透镜阵列直接形成于所述感光像素的表面。所述微透镜阵列直接与所述感光像素集成，不仅能够有效提高器件集成度、提高器件稳定性，而且还能够减少后期装配步骤，降低装配难度。
本发明可选方案中，所述微透镜为平面型透镜，即所述微透镜中，所有凸起部的表面高度一致，光线透射的表面均为平面，光线透射的表面不是曲面，所述微透镜朝向封装材料的表面平行于所述感光像素的表面。采用平面型透镜，避免曲面能够有效保证制作工艺的可控性，能够有效保证微透镜的精度。
附图说明
为了更清楚地说明本发明实施例或现有技术中的技术方案，下面将对实施例或现有技术描述中所需要使用的附图作简单地介绍，显而易见地，下面描述中的附图仅仅是本发明的一些实施例，对于本领域普通技术人员来讲，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他的附图。
图1是一种探测单元的剖面结构示意图；
图2是本发明探测单元第一实施例的剖面结构示意图；
图3是图2所示探测单元中微透镜阵列内一个微透镜会聚光线的光路结构示意图；
图4是图3所示微透镜的放大结构示意图；
图5是图3所示微透镜透射光线时光线的相位分布示意图；
图6是本发明探测单元第二实施例中微透镜透射光线时光线的相位分布示意图；
图7是图6所示探测单元实施例中超表面透镜内凸起部与传输相位之间的关系；
图8是本发明探测单元第三实施例的剖面结构示意图；
图9是图8所示探测单元实施例中微透镜对于平行入射的光线的聚焦情况；
图10是本发明探测单元第四实施例的结构示意图；
图11是图10所示探测单元实施例中微透镜对于平行入射的光线的聚焦情况；
图12是本发明探测单元第五实施例中微透镜对于平行入射的光线的聚焦情况。
具体实施方式
由背景技术可知，现有技术中经上色处理的指纹成像模组存在成像效果不佳的问题。现结合所述指纹成像模组的结构分析其成像效果不佳问题的原因：
由背景技术可知，现有技术中即使设置了微透镜阵列，探测单元的探测效率依旧较低。现结合一种探测单元的结构分析其探测效率低问题的原因：
如图1所示，示出了一种探测单元的剖面结构示意图。
所述探测单元包括：基板11；感光像素12，所述感光像素12位于所述基板11上，所述感光像素12的一侧和所述基板11通过导电银胶13实现连接和固定，所述感光像素12的另一侧和所述基板11内的互连结构14a通过连接线14连接；微透镜阵列15，所述微透镜阵列15位于所述感光像素12上。
所述感光像素12包括多个感光器件(图中未示出)。所述感光器件为单光子感光器件，例如SPAD器件阵列或SiPM器件。所述微透镜阵列15包括多个微透镜，所述微透镜与所述感光器件一一对应，所述微透镜适宜于将光信号会聚至所对应感光器件的感光区域。
所述微透镜阵列15通常采用光刻胶熔融技术(即立方体形状的光刻胶熔融后形成球形)、纳米压印技术等方法制备。这些制备方法对微透镜形貌和精度的控制精度较低，而且微透镜阵列还容易出现填充因子低于100％的问题，从而造成了微透镜阵列折射效果发生变化，光学性能不稳定，难以将光信号很好的会聚至感光器件的感光区域，从而引起了探测单元探测效率低下的问题。
而且微透镜阵列无法完全填充、填充因子低于100％，也会使微透镜阵列、使探测单元中出现不可预计的空隙，从而引起器件的可靠性风险。
另外，如图1所示，所述探测单元还包括：封装层16，所述封装层16覆盖所述基板11、所述感光像素12以及所述微透镜阵列。现有方法中，可靠性最好、成本最低的封装方案是基于有机材料的封装方案，即所述封装层16的材料是有机材料。而常用的光刻胶熔融技术(即立方体形状的光刻胶熔融后形成球形)、纳米压印技术等方法制备的微透镜阵列15的材料通常也是有机材料。
因此，所述微透镜阵列15的材料的折射率与所述封装层16的材料的折射率很接近，如果直接封装，即所述封装层16直接覆盖所述微透镜阵列15的表面，所述封装层16与所述微透镜阵列15的表面直接接触，会导致所述微透镜阵列15和所述封装层16界面两侧材料的折射率过于接近，从而影响甚至消除微透镜的折射作用，使微透镜会聚光线的能力削弱甚至失效。
为了在实现封装的同时保证光学作用，所述微透镜阵列15和所述封装层16之间设置有空气隙17，即所述封装层16与所述微透镜阵列15起光学作用的表面并不直接接触，在所述封装层16下方，所 述微透镜阵列15上方留有空气。但是空气受环境影响较大，空气隙17的存在会造成器件可靠性降低，而且也对封装工艺提出了很高的要求，增加了封装工艺的复杂度。
尤其当所述探测单元应用于车载激光雷达时，空气隙17的存在对车规认证是一个较大的挑战。
为解决所述技术问题，本发明提供一种探测单元，包括：
感光像素，所述感光像素包括多个感光器件；微透镜阵列，所述微透镜阵列位于光入射所述感光像素光的一侧，所述微透镜阵列包括多个微透镜，所述微透镜与所述感光器件一一对应；所述微透镜包括凸起部，所述凸起部的材料为无机材料。
本发明技术方案，用以会聚光线的凸起部的材料为无机材料。所述凸起部的材料的折射率与所述探测单元的封装材料的折射率之间差异较大，因此能够在所述微透镜表面直接封装，即所述封装材料能够与所述微透镜表面直接接触，封装材料和微透镜之间无需保留空气隙，能够有效提高器件可靠性，降低封装难度；特别是针对车载设备，避免空气隙的形成有利于通过车规认证。
为使本发明的上述目的、特征和优点能够更为明显易懂，下面结合附图对本发明的具体实施例做详细的说明。
参考图2，示出了本发明探测单元一实施例的剖面结构示意图。
所述探测单元包括：感光像素110，所述感光像素110包括多个感光器件(图中未示出)；微透镜阵列120，所述微透镜阵列120位于光入射所述感光像素110的一侧，所述微透镜阵列120包括多个微透镜121，所述微透镜121与所述感光器件一一对应；所述微透镜121包括凸起部122，所述凸起部122的材料为无机材料。
用以会聚光线的凸起部122的材料为无机材料。所述凸起部122的材料的折射率与所述探测单元的封装材料的折射率之间差异较大，因此所述微透镜121表面能够直接进行封装而不会影响其光学性能， 即所述微透镜121表面能够直接与封装材料接触而不影响光学性能，所述微透镜121和封装材料之间无需保留空气隙，能够有效提高器件可靠性，降低封装难度；特别是针对车载设备，避免空气隙的形成有利于通过车规认证。
所述感光像素110适宜于接收光信号并对光信号进行光电转换。所述感光像素110包括多个感光器件，所述多个感光器件呈阵列排布。
本发明一些实施例中，所述感光器件为单光子探测器件。具体的，所述感光器件包括：SPAD器件。SPAD(Single Photon Avalanche Diode)器件，即单光子雪崩二极管，是工作在盖革模式下的雪崩光电二极管，可以用于对弱光信号甚至单光子信号的探测。作为光电探测器的应用形式主要是SPAD阵列或硅光电倍增管(Silicon photomultiplier，SiPM)。
本发明一些实施例中，所述感光像素110位于基板101上，所述感光像素110的一侧和所述基板101通过导电银胶102实现连接和固定，所述感光像素110的另一侧和所述基板101内的互连结构103通过连接线104连接。
所述微透镜阵列120适宜于调整入射至所述感光像素110的光线。
具体的，所述微透镜阵列120包括呈阵列排布的多个微透镜。所述多个微透镜与所述多个感光器件一一对应，即所述微透镜适宜于调整入射至所对应感光器件的光线。
所述微透镜包括凸起部122。所述凸起部122适宜于会聚光线。具体的，所述凸起部122的材料为无机材料。所述凸起部122与后期封装过程中所采用的封装材料的折射率相差很大，因此即使所述凸起部122与封装材料直接接触也不会影响其光学性能，也就是说，可以在所述微透镜121的凸起部122的表面直接封装，无需保留空气隙。
本发明一些实施例中，所述感光器件为单光子探测器，因此所述微透镜阵列120中的微透镜适宜于将透射的光信号会聚至所对应感 光器件的耗尽层。单光子探测器表面适于透射光信号的区域为光敏面，光敏面周围需要制备电极、光隔离结构等部件，因此感光器件的光敏面相比于所述感光器件的总表面积所得的填充因子比较小，但是只有透过光敏面入射至所述感光区域(即耗尽层)的光子才会被感光器件有效探测。所以所述微透镜的设置能够有效提高入射至对应感光器件的耗尽层的光的强度，以提高单光子探测器的探测效率。
本发明一些实施例中，所述无机材料为硅(折射率3.5左右)。采用硅材料制作所述凸起部122，能够通过波段选择以尽量降低光损耗；而且将所述凸起部122的材料设置为硅，能够与所述感光像素110的制作工艺相兼容，能够在同一工艺流程中制作所述感光像素110和所述微透镜阵列120。
需要说明的是，本发明一些实施例中，所述微透镜包括基底(图中未标示)，所述凸起部122位于所述基底表面，且所述基底和所述凸起部122为一体结构。本发明另一些实施例中，所述微透镜也可以仅包括所述凸起部122。
本发明一些实施例中，所述微透镜阵列120形成于所述感光像素110的表面，直接在所述感光像素110的表面形成所述微透镜阵列120，所述微透镜阵列120朝向所述感光像素110的表面与所述感光像素110朝向所述微透镜阵列120的表面直接接触。所述透镜阵列直接形成于所述感光像素110的表面。所述微透镜阵列120直接与所述感光像素110集成，不仅能够有效提高器件集成度、提高器件稳定性，而且还能够减少后期装配步骤，降低装配难度。
本发明一些实施例中，所述探测单元还包括：包覆材料123，所述包覆材料123至少填充于相邻凸起部122之间的空隙，所述包覆材料123的折射率低于所述凸起部122的材料的折射率。所述包覆材料123填充于所述凸起部122之间起到保护增强的作用。具体的，所述包覆材料123的折射率低于所述凸起部122的材料的折射率，例如所述包覆材料123可以是聚合物或者硅化合物等。
本发明一些实施例中，所述包覆材料123的顶部表面高于所述凸起部122的顶部表面。使包覆材料123的顶部表面高于所述凸起部122的顶部表面，能够使所述包覆材料123完全覆盖所述凸起部122，从而能够有效保护所述凸起部，以便于后续封装。
本发明一些实施例中，所述探测单元还包括：封装层130，所述封装层至少位于所述微透镜阵列120上。所述封装层适宜于保护所述探测单元。本发明一些实施例中，所述凸起部之间填充的包覆层材料的顶部表面高于所述凸起部122的顶部表面，因此所述封装层与所述包覆材料123直接接触，即在所述包覆材料123表面直接进行封装。本发明另一些实施例中，所述包覆材料123露出所述凸起部122或者所述探测单元并不包括所述封装层时，所述封装材料与所述凸起部的表直接接触，即在所述微透镜阵列120的表面直接封装。
本发明一些实施例中，形成所述微透镜阵列120的过程包括：沉积工艺。具体的，形成所述微透镜阵列120的过程包括：在所述感光像素110表面沉积透镜材料层；在所述透镜材料层表面形成图案化层，所述图案化层暴露出所述透镜材料层的待刻蚀区域；以所述图案化层为掩膜，刻蚀所述微透镜材料层以形成具有所述凸起部的微透镜阵列120。一些实施例中，所述相邻凸起部122之间还填充有包覆材料123，因此刻蚀形成微透镜阵列120之后，还包括：在相邻凸起部之间填充包覆材料123。
如图2所示，本发明一些实施例中，所述微透镜为平面型微透镜，即所述微透镜中，所有凸起部的表面高度一致，光线透射的表面均为平面，光线透射的表面不是曲面。具体的，所述微透镜朝向封装材料的表面平行于所述感光像素110的表面。采用平面型透镜，避免曲面能够有效保证制作工艺的可控性，能够有效保证微透镜的精度。
具体的，本发明一些实施例中，所述微透镜包括：多个凸起部122，所述微透镜为衍射型透镜，即光线在投射所述多个凸起部122过程中发生衍射以实现会聚效果。
所述微透镜为衍射型透镜，所述微透镜不需要依靠表面折射率差所产生的折射作用，因此无论微透镜表面是空气还是折射率不同的封装材料，都不会影响其衍射作用，即所述微透镜的光学性能不受与其接触的材料影响，能够直接与封装材料接触。
结合参考图3至图5，其中图3示出了图2所示探测单元中微透镜阵列120中一个微透镜会聚光线的光路结构示意图，图4示出了图3所示微透镜的放大结构示意图，图5示出了图3所示微透镜透射光线时光线的相位分布示意图。
本发明一些实施例中，所述微透镜121为菲涅尔波带片(Binary Fresnel Zone Plate，FZP)。菲涅尔波带片是由一系列不同半径、不同宽度的凸起的圆环构成。所述微透镜为菲涅尔波带片时，在平行于所述感光像素110表面的平面内，所述凸起部122的截面为圆环状，而且所述多个凸起部122呈同心圆环分布(如图5中小图501所示)。
如图5所示，横轴表示所述凸起部122的截面半径，纵轴表示相位。线条502表示微透镜表面轮廓。具体的，结合图4，所述凸起部122顶部表面122a和所述凸起部122之间基底124表面124a之间相位差为π，即圆环顶部表面和圆环之间空隙底部表面之间相位差为π。
所以，通过控制所示凸起部122凸起于基底124表面124a的高度h使所述凸起部122顶部表面122a和所述凸起部122之间基底124表面124a之间相位差满足预设要求。所述凸起部122顶部表面122a与所述凸起部122之间基底124表面124a之间的相位差与所述凸起部122凸起于基底124的高度h之间的关系为：
Figure PCTCN2022098331-appb-000001
其中，n为所述凸起部122材料的折射率，n 0为所述凸起部122之间空隙材料的折射率，λ为透射光线的波长。
另外，所述凸起部122的半径为：
Figure PCTCN2022098331-appb-000002
其中，n为凸起部下方材料(如基底124)的折射率，k为圆环阶数。
具体的，图4中半径R1表示凸起部中1阶圆环的半径，即凸起部中，阶数k＝1的圆环的半径，图4中半径R2表示凸起部中2阶圆环的半径，即凸起部中，阶数k＝2的圆环的半径。半径R1和半径R2的具体大小可以根据上面R k的公式获得。
参考图6，示出了本发明探测单元另一实施例中微透镜透射光线时光线的相位分布示意图。
本发明一实施例中，所述微透镜还可以为超表面透镜(Metalens)。超表面透镜由周期性排列的不同截面尺寸的结构单元构成，每种结构单元对应一个不同的相位变化，根据目标空间相位分布在不同位置设置对应的结构单元。
本发明一些实施例中，结构单元为圆柱或长方体。因此，所述微透镜为超表面透镜时，在平行所述感光像素表面的平面内，所述凸起部222的截面为圆形或长方形，所述多个凸起部222的截面尺寸并不相同。而且所述多个凸起部222以预设规律分布于平行所述感光像素表面的平面内(如图6中小图601所示)。
如图6中，以结构单元(凸起部222)为圆柱作为示意，横轴表示所述凸起部222中心与所述微透镜中心的距离，纵轴表示相位。线条602表示微透镜不同位置的相位。以r表示所述凸起部222中心与所述微透镜中心的距离，r处的相位为：
Figure PCTCN2022098331-appb-000003
每一个所述凸起部222都会引起一个相位延迟，可以基于波导模 型进行如下的理论计算：
Figure PCTCN2022098331-appb-000004
其中，λ为透射光线的波长，n eff为所述凸起部222中传输的基模的有效折射率，H为所述凸起部222的高度。
每个所述凸起部222高度H相同，每个所述凸起部222所引起相位延迟的大小主要与所述凸起部222的截面尺寸有关(即所述凸起部222的截面尺寸影响n eff)。
结合参考图7，示出了图6所示探测单元实施例中超表面透镜中凸起部与传输相位之间的关系。
具体的，所述微透镜的凸起部222为圆柱体，图7中横轴表示凸起部222的截面半径，纵轴表示传输相位，数据线701表示FDTD仿真的结果，数据线702表示波导模型计算结果。
需要说明的是，实际设计可以以仿真结果或基于上述公式理论计算为基准。或者，以仿真结果为基准，以波导模型计算结果为参考。
由上述描述可知，本发明一些实施例的微透镜为衍射型透镜，微透镜的结构尺寸与透射光线的波长相关。根据感光器件所需感应的光线波长(工作波长)，获得微透镜的结构尺寸，能够使得微透镜对于工作波长的入射光具有最佳的聚焦效果，工作波长以外的干扰光无法有效聚焦，从而能够降低干扰光对感应器件的影响。
结合参考图6和图7，所述凸起部222的尺寸与所述凸起部222所处位置所需要的相位延迟相关，因此基于预设的焦距f和距离r，计算不同位置凸起部222所需的相位差，进而基于所述相位差获得所述凸起部222的截面尺寸。
需要说明的是，本发明一些实施例中，所述探测单元还包括：空气隙，所述空气隙至少位于相邻凸起部222之间。空气的折射率很低，在相邻凸起部222之间保留空气隙，在扩大凸起部222与周围环境之 间的折射率差以保证良好光学性能的同时，工艺难度不高，对封装影响较低。
还需要说明的是，本发明一些实施例中，所述微透镜的焦距大于所述感光器件的表面到耗尽层的距离。所述距离为耗尽层到感光器件表面的垂直距离。增大微透镜的焦距，在口径不变的情况下减小其数值孔径，有利于降低加工难度，提高微透镜的加工精度和聚焦效果。本发明的微透镜焦距相对较大，能够适用于背照式感光器件和正照式感光器件。
参考图8，示出了本发明探测单元再一实施例的剖面结构示意图。
本发明一些实施例中，所述微透镜812适宜于将光信号会聚至所对应感光器件811的高电场区域813，也就是说，所述微透镜812的焦距满足预设条件，以使将光线会聚所对应感光器件811的高电场区域813。
如图8所示，本发明一些实施例中，所述感光器件811为背照式(back side illumination，BSI)感光器件811，也就是说，所述感光器件811的电极814位于一侧，光线从所述感光器件811的另一侧入射。所述高电场区域813位于感光器件811的耗尽层。
具体的，所述感光器件811具有设置电极814的第一面811a以及与所述第一面811a相背的第二面811b；所述微透镜阵列位于所述第二面811b的一侧。所以，所述感光器件811包括外延层815，所述外延层815适宜于吸收光子以实现探测；电极814，所述电极814位于所述外延层815一侧的表面；所述微透镜812位于所述外延层815远离所述电极814一侧的表面。光信号透射所述微透镜812后入射至所述外延层815，所述微透镜812将透射光线会聚至所述外延层815中的高电场区域813。
本发明一些实施例中，光信号依次透射所述微透镜阵列和所述感光器件811后，在所述感光器件811的第一面811a反射。光线入射 至所述外延层815后，部分光信号被所述外延层815吸收以实现探测；部分光线透射所述外延层815设置所述电极814的一侧的表面发生反射，再次入射至所述外延层815以增加吸收探测的几率。
本发明一些实施例中，所述探测单元还包括：反射层816，所述反射层816位于所述感光器件811的第一面811a。所述反射层816适宜于提高穿透感光器件811的光线在所述感光器件811的第一面811a发生反射的几率。
对于微透镜阵列来说，微透镜812往往口径大，焦距短，因此一般来说，微透镜阵列中的微透镜812往往具有较大的数值孔径(NA)。而大数值孔径的透镜的加工难度一般较大。但是，如图8所示实施例中，所述微透镜812的焦距使入射光经所述电极814或所述反射层816反射后再聚焦在焦点，从而可以在保持口径不变的情况下增大所述微透镜812焦距，从而能够有效减小所述微透镜812的数值孔径，进而降低所述微透镜812的加工难度。特别是当所述微透镜812为超表面透镜时，数值孔径的减小，还能有效改善所述微透镜812的透过率和聚焦效果。
结合参考图9，示出了图8所示探测单元实施例中所述微透镜812对于平行入射的光线的聚焦情况。
需要说明的是，图8所示实施例中，所述微透镜阵列中的微透镜812为超表面透镜。
具体的，其中横轴表示所述凸起部中心与所述微透镜812中心的距离，纵轴表示与所述感光器件811光入射的表面之间的距离。图9中的虚线901和虚线902之间为超表面透镜所对应的区域，虚线902和虚线903之间为所述感光器件811中覆盖所述外延层815的介质层所对应的区域(所述介质层能够起到隔离保护、抗反射的作用，所述介质层的材料包括氧化硅、氮化硅中的至少一种)，虚线903和虚线904之间为所述感光器件811的外延层815所对应的区域，虚线904和横轴之间为所述电极814所对应的区域。
如图9所示，利用背照式感光器件811与电极814、反射层816的结合，能够有效延长所述微透镜812的焦距，使光线被电极814和反射层816反射后会聚至所述感光器件811外延层815的高电场区域813，所述微透镜812能够有效实现光线的聚焦作用。具体的，在背照式感光器件811与电极814、反射层816结合的实施例中，所述微透镜812的焦距应为感光器件811的外延层815的厚度与反射层816表面到高电场区域813之间距离之和。
结合参考图10，示出了本发明探测单元另一实施例的结构示意图。
本发明一些实施例中，所述感光器件1011为正照式(front side illumination，FSI)感光器件，也就是说，光线从所述感光器件1011设置有电极1014的一侧入射。
具体的，所述感光器件1011具有设置电极1014的第一面1011a以及与所述第一面1011a相背的第二面1011b；所述微透镜阵列位于所述第一面1011a的一侧。所以，所述感光器件1011的电极1014和所述微透镜阵列依次层叠于所述感光器件1011外延层的一侧表面上。光信号透射所述微透镜1012后入射至所述外延层，所述微透镜1012将透射光线会聚至所述外延层中的高电场区域1013。所述高电场区域1013位于感光器件1011的耗尽层。
需要说明的是，图10所示实施例中，所述感光器件1011具有2个电极，其中一个电极1014位于所述第一面1011a，另一个电极1014位于所述第二面1011b。FSI器件的电极1014与高电场区域1013之间有比较厚的衬底区域，光在衬底内传播过程中就会被完全吸收，无法被电极1014反射回高电场区域。
如图10所示，本发明一些实施例中，所述微透镜1012还包括：填充层1016，所述填充层1016位于所述感光器件1011的第一面1011a上。所述填充层1016适宜于增大所述微透镜1012和所对应感光器件1011的高电场区域1013之间的距离，从而达到增大焦距、减小数值 孔径的目的；而且还能够使会聚后的光线避开电极以提高探测效率。
具体的，所述填充层1016的材料为低光损耗材料。采用低光损耗材料制备所述填充层1016，能够有效减小光线透射所述填充层1016时候的损耗，能够有效提高探测效率。例如，所述填充层1016的材料可以为氧化硅。氧化硅材料与所述感光器件1011和所述微透镜阵列的制作工艺兼容性高，能够有效降低填充层1016设置的影响。所述填充层1016的厚度根据所述微透镜1012的数值孔径和工艺限制决定，也就是说，基于工艺限制设计所述微透镜1012的数值孔径，以确定最短的焦距f，进而根据焦距f确定所述填充层1016的厚度，即焦距f减去感光器件1011表面到高电场区域的距离即为所述填充层1016的厚度。
结合参考图11，示出了图10所示探测单元实施例中所述微透镜1012对于平行入射的光线的聚焦情况。
需要说明的是，图10所示实施例中，所述微透镜阵列中的微透镜1012为超表面透镜。
具体的，其中横轴表示所述凸起部中心与所述微透镜1012中心的距离，纵轴表示距离所述感光器件1011光入射的表面的距离。图11中的虚线1101和虚线1102之间为超表面透镜所对应的区域，虚线1102和虚线1103之间为所述填充层1016所对应的区域，虚线1103和横轴之间为所述感光器件1011的外延层所对应的区域。
如图11所示，光线透射所述超表面透镜和所述填充层1016后，聚焦在所述感光器件1011的外延层，并在靠近所述外延层中所形成PN结的高电场区域，因而可以保证光信号被集中于所述高电场区域，能够有效增加光信号被吸收并激发载流子的概率，进而引发雪崩效应，能够有效提高光信号的有效探测。
需要说明的是，前述实施例中，所述微透镜均为超表面微透镜。超表面透镜具有更高的聚焦效率，能够更有效的提高探测效率。但是 将超表面微透镜与背照式感光器件相结合，或者将超表面微透镜与正照式感光器件相结合的做法，均为示意。本发明其他实施例中，与背照式感光器件相结合的微透镜或者与正照式感光器件相结合的微透镜也都可以是菲涅尔波带片。
结合参考图12，示出了本发明再一探测单元实施例中所述微透镜对于平行入射的光线的聚焦情况。
需要说明的是，图12所示实施例中，所述微透镜阵列中的微透镜为菲涅尔波带片；而且所述感光器件为正照式感光器件，所述微透镜和所述感光器件之间也设置有填充层。
具体的，其中横轴表示所述凸起部的半径，纵轴表示距离所述感光器件光入射的表面的距离。图12中的虚线1201和虚线1202之间为菲涅尔波带片所对应的区域，虚线1202和虚线1203之间为所述填充层所对应的区域，虚线1203和横轴之间为所述感光器件的外延层所对应的区域。
如图12所示，所述菲涅尔波带片也能够使入射光线聚焦中高电场区域。菲涅尔波带片的尺寸更大，加工难度更低，能够有效提高良率。
相应的，本发明还提供一种探测阵列，具体包括：呈阵列排布的探测单元，所述探测单元为本发明的探测单元。
所述探测单元为本发明的探测单元，因此所述探测单元的具体技术方案参考前述探测单元的实施例，本发明在此不再赘述。
所述探测单元中的微透镜用以会聚光线的凸起部的材料为无机材料。所述凸起部的材料的折射率与所述探测单元的封装材料的折射率之间差异较大，因此能够在所述微透镜表面直接封装，即所述封装材料能够与所述微透镜表面接触，能够有效封装材料和微透镜之间无需保留空气隙，能够有效提高器件可靠性，降低封装难度；特别是针对车载设备，避免空气隙的形成有利于通过车规认证。
相应的，本发明还提供一种探测阵列母板，具体包括：多个探测阵列，所述探测阵列为本发明的探测阵列。
所述探测阵列为本发明的探测阵列，因此所述探测阵列的具体技术方案参考前述探测阵列记载，本发明在此不再赘述。
此外，本发明还提供一种探测器，包括：至少一个探测阵列，所述探测阵列为本发明的探测阵列。
所述探测阵列为本发明的探测阵列，因此所述探测阵列的具体技术方案参考前述探测阵列记载，本发明在此不再赘述。
所述探测阵列中探测单元内的所述微透镜用以会聚光线的凸起部的材料为无机材料。所述凸起部的材料的折射率与所述探测单元的封装材料的折射率之间差异较大，因此能够在所述微透镜表面直接封装，即所述封装材料能够与所述微透镜表面接触，能够有效封装材料和微透镜之间无需保留空气隙，能够有效提高器件可靠性，降低封装难度；特别是针对车载设备，避免空气隙的形成有利于通过车规认证。
所述探测器中探测阵列的封装无需保留空气隙，封装难度低、可靠性高，所述探测器更符合车规认证。
另外，本发明还提供一种激光雷达，所述激光雷达包括：光源，所述光源适宜于产生光线；探测器，所述探测器适宜于接收回波光，所述探测器为本发明的探测器。
综上，本发明技术方案中，所述微透镜用以会聚光线的凸起部的材料为无机材料。所述凸起部的材料的折射率与所述探测单元的封装材料的折射率之间差异较大，因此能够在所述微透镜表面直接封装，即所述封装材料能够与所述微透镜表面接触，能够有效封装材料和微透镜之间无需保留空气隙，能够有效提高器件可靠性，降低封装难度；特别是针对车载设备，避免空气隙的形成有利于通过车规认证。
而且，所述微透镜阵列直接形成于所述感光像素的表面。所述微透镜阵列直接与所述感光像素集成，不仅能够有效提高器件集成度、 提高器件稳定性，而且还能够减少后期装配步骤，降低装配难度。
此外，所述微透镜为平面型透镜，即所述微透镜中，所有凸起部的表面高度一致，光线透射的表面均为平面，光线透射的表面不是曲面，所述微透镜朝向封装材料的表面平行于所述感光像素的表面。采用平面型透镜，避免曲面能够有效保证制作工艺的可控性，能够有效保证微透镜的精度。
虽然本发明披露如上，但本发明并非限定于此。任何本领域技术人员，在不脱离本发明的精神和范围内，均可作各种更动与修改，因此本发明的保护范围应当以权利要求所限定的范围为准。

Claims (25)

  1. 一种探测单元，其特征在于，包括：
    感光像素，所述感光像素包括多个感光器件；
    微透镜阵列，所述微透镜阵列位于光入射所述感光像素的一侧，所述微透镜阵列包括多个微透镜，所述多个微透镜与所述多个感光器件一一对应；
    所述微透镜包括凸起部，所述凸起部的材料为无机材料。
  2. 如权利要求1所述的探测单元，其特征在于，所述无机材料为硅。
  3. 如权利要求1或2所述的探测单元，其特征在于，所述微透镜阵列形成于所述感光像素的表面。
  4. 如权利要求1所述的探测单元，其特征在于，形成所述微透镜阵列的过程包括：沉积工艺。
  5. 如权利要求1所述的探测单元，其特征在于，所述微透镜为平面型微透镜。
  6. 如权利要求5所述的探测单元，其特征在于，所述微透镜包括多个凸起部，所述微透镜为衍射型透镜。
  7. 如权利要求6所述的探测单元，其特征在于，所述微透镜为菲涅尔波带片和超表面透镜中的至少一种。
  8. 如权利要求1、5～7中任一项所述的探测单元，其特征在于，所述微透镜适宜于将光信号会聚至所对应感光器件的高电场区域。
  9. 如权利要求8所述的探测单元，其特征在于，所述感光器件为背照式感光器件；
    所述感光器件具有设置电极的第一面以及与所述第一面相背的第二面；
    所述微透镜位于所述第二面的一侧。
  10. 如权利要求9所述的探测单元，其特征在于，还包括：反射层，
    所述反射层位于所述感光器件的第一面。
  11. 如权利要求9所述的探测单元，其特征在于，光信号依次透射所述微透镜阵列和所述感光器件后，在所述感光器件的第一面反射。
  12. 如权利要求8所述的探测单元，其特征在于，所述感光器件为正照式感光器件；
    所述感光器件具有设置电极的第一面以及与所述第一面相背的第二面；
    所述微透镜阵列位于所述第一面的一侧。
  13. 如权利要求12所述的探测单元，其特征在于，所述微透镜还包括：
    填充层，所述填充层位于所述感光器件的第一面上。
  14. 如权利要求13所述的探测单元，其特征在于，所述填充层的材料为低光损耗材料。
  15. 如权利要求14所述的探测单元，其特征在于，所述填充层的材料为氧化硅。
  16. 如权利要求1所述的探测单元，其特征在于，还包括：包覆材料，所述包覆材料至少填充于相邻凸起部之间的空隙，所述包覆材料的折射率低于所述凸起部的材料的折射率。
  17. 如权利要求16所述的探测单元，其特征在于，所述包覆材料的顶部表面高于所述凸起部的顶部表面。
  18. 如权利要求1所述的探测单元，其特征在于，还包括：空气隙，所述空气隙至少位于相邻凸起部之间。
  19. 如权利要求1、16～18中任一项所述的探测单元，其特征在于，还包括：封装层，所述封装层至少位于所述微透镜阵列上。
  20. 如权利要求1所述的探测单元，其特征在于，所述感光器件为单 光子探测器件。
  21. 如权利要求20所述的探测单元，其特征在于，所述微透镜适宜于将光信号会聚至所对应感光器件的耗尽层。
  22. 一种探测阵列，其特征在于，包括：
    呈阵列排布的探测单元，所述探测单元如权利要求1～21中任一项所述。
  23. 一种探测阵列母板，其特征在于，包括：
    多个探测阵列，所述探测阵列如权利要求22所述。
  24. 一种探测器，其特征在于，包括：
    至少一个探测阵列，所述探测阵列如权利要求22所述。
  25. 一种激光雷达，其特征在于，包括：
    光源，所诉光源适宜于产生光线；
    探测器，所述探测器适宜于接收回波光，所述探测器如权利要求24所述。
PCT/CN2022/098331 2021-12-09 2022-06-13 探测单元、探测阵列、探测阵列母板、探测器和激光雷达 WO2023103314A1 (zh)

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