Photoelectric detector, TOF module and electronic equipment

Abstract

The utility model provides a photoelectric detector, TOF module and electronic equipment wherein the photoelectric detector includes: SPAD array, the SPAD array is used for generating photoelectric effect and converting optical signal into electrical signal, also includes: filter layer, be provided in the incident light surface of SPAD array, filter layer is used for filtering external incident light, be provided in the incident light surface of SPAD array, and be provided in the incident light surface of SPAD array. Only signal light with a specific wavelength is allowed to pass through and enter the SPAD array; the scattering layer is arranged on the light incident surface of the SPAD array, is positioned between the light filtering layer and the reflecting layer, and is used for changing the incident angle of the signal light in the SPAD array; the reflecting layer is arranged on the non-incident surface of the SPAD array and is used for reflecting the signal light incident into the SPAD array to obtain large-angle reflected light; and the light filtering layer is also used for preventing the large-angle reflected light from passing through and being emitted to the outside, so that the large-angle reflected light is reflected back to the SPAD array. According to the utility model, the photoelectric detector performance with high PDE and low reflectivity can be realized.

Description

Technical Field

[0001] The utility model relates to the field of photoelectric detection, in particular to a photoelectric detector, a TOF module and an electronic device. Background Art

[0002] The TOF camera is an active optical system that uses the laser pulse at the transmitting end to touch the target object, and the photodetector at the receiving end identifies the target signal, and then calculates the depth information of the target through the flight time. Therefore, the photon detection efficiency (PDE) of the photodetector determines the sensitivity of the system and the maximum detectable distance. Generally, the signal light of the photodetector directly enters the light absorbing material. Since the light absorbing material in the photodetector cannot be too thick, and there is a metal back reflection layer, the photons received by the receiving end can only absorb part of the energy and reflect the rest back. This not only reduces the PDE of the photodetector, but also causes crosstalk due to the reflected light, which ultimately affects the ranging performance of the module. Therefore, the existing technology needs to be improved and enhanced. Utility Model Content

[0003] In view of the above-mentioned deficiencies in the prior art, an object of the present invention is to provide a photoelectric detector, a TOF module and an electronic device.

[0004] In order to solve the above technical problems, the utility model adopts the following technical solutions:

[0005] The utility model provides a photoelectric detector, comprising: a SPAD array, wherein the SPAD array is used to generate a photoelectric effect and convert an optical signal into an electrical signal, and further comprising:

[0006] A filter layer, disposed on the light incident surface of the SPAD array, the filter layer is used to filter external incident light and only allow signal light of a specific wavelength to pass through and enter the SPAD array;

[0007] A scattering layer, disposed on the light incident surface of the SPAD array and located between the filter layer and the reflective layer, for changing the incident angle of the signal light in the SPAD array;

[0008] A reflective layer, disposed on the non-light incident surface of the SPAD array, for reflecting the signal light incident on the SPAD array to obtain reflected light at a large angle;

[0009] The filter layer is also used to prevent the reflected light at a large angle from passing through and emitting to the outside, so as to reflect the reflected light at a large angle back to the SPAD array.

[0010] Furthermore, in the photoelectric detector, the filter layer is a bandpass filter film layer.

[0011] Furthermore, in the photoelectric detector, the scattering layer is a grating layer.

[0012] Furthermore, in the photodetector, the reflective layer includes a peripheral reflective layer and a bottom reflective layer, the peripheral reflective layer is arranged on the four sides of the SPAD array, and the bottom reflective layer is arranged on the non-light incident surface of the SPAD array; the reflective layer is a metal layer.

[0013] Furthermore, in the photodetector, the peripheral reflective layer is a deep trench isolation structure.

[0014] Furthermore, in the photoelectric detector, the structural parameters of the filter layer include material properties, material thickness, material order, and number of layers.

[0015] Furthermore, in the photoelectric detector, the parameters of the bandpass filter thin film layer include passband range, passband width, and blue shift coefficient of the passband varying with angle.

[0016] Furthermore, in the photoelectric detector, the bandpass filter film layer has a passband range of 940±10nm at an incident angle of 0 degrees; a passband range of 925±10nm at an incident angle of 15 degrees; and a passband range of 890±10nm at an incident angle of 30 degrees.

[0017] The utility model also provides a TOF module, comprising the photoelectric detector as described above, and also comprising a laser emitter for emitting laser.

[0018] The utility model also provides an electronic device, comprising the photoelectric detector as described above, and also comprising a controller for controlling the photoelectric detector to start a function of receiving light.

[0019] Compared with the prior art, the utility model provides a photodetector, a TOF module and an electronic device, wherein the photodetector includes: a SPAD array, the SPAD array is used to generate a photoelectric effect and convert an optical signal into an electrical signal, and also includes: a filter layer, which is arranged on the light incident surface of the SPAD array, the filter layer is used to filter external incident light, and only allows signal light of a specific wavelength to pass through and enter the SPAD array; a scattering layer, which is arranged on the light incident surface of the SPAD array and is located between the filter layer and the reflective layer, and is used to change the incident angle of the signal light in the SPAD array; a reflective layer, which is arranged on the non-light incident surface of the SPAD array, and is used to reflect the signal light incident into the SPAD array to obtain reflected light at a large angle; the filter layer is also used to prevent the reflected light at a large angle from passing through and emitting to the outside, so as to reflect the reflected light at a large angle back to the SPAD array. The utility model is conducive to achieving photodetector performance with high PDE and low reflectivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a structural schematic diagram of the photoelectric detector provided by the utility model.

[0021] Figure 2 A schematic diagram of the transmission spectrum of a bandpass filter thin film layer provided by the utility model.

[0022] Figure 3 A schematic diagram comparing the PDE of the photoelectric detector provided by the utility model and the traditional photoelectric detector.

[0023] Figure 4 A schematic diagram comparing the reflectivity of the photoelectric detector provided by the utility model and the traditional photoelectric detector. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solution and advantages of the utility model more clear, the utility model is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the utility model and are not used to limit the utility model.

[0025] It should be noted that when a component is referred to as being "mounted on", "fixed on" or "disposed on" another component, it may be directly on the other component or there may be a central component at the same time. When a component is referred to as being "connected to" another component, it may be directly connected to the other component or there may be a central component at the same time.

[0026] It should also be noted that the directional terms such as left, right, up, and down in the embodiments of the present invention are merely relative concepts or are based on the normal use status of the product and should not be considered as restrictive.

[0027] like Figure 1As shown, the utility model provides a photoelectric detector, including: a SPAD array 30, the SPAD array 30 is used to generate a photoelectric effect and convert an optical signal into an electrical signal, and also includes a filter layer 10, a scattering layer 20 and a reflective layer 40. Among them, the filter layer 10 is arranged on the light incident surface of the SPAD array 30, and the filter layer 10 is used to filter the external incident light, allowing only signal light of a specific wavelength to pass through and enter the SPAD array 30; it is also used to prevent the reflected light with a large angle from passing through and emitting outside, so as to reflect the reflected light with a large angle back to the SPAD array 30. The scattering layer 20 is arranged on the light incident surface of the SPAD array 30, and is located between the filter layer 10 and the reflective layer 40, and is used to change the incident angle of the signal light in the SPAD array 30; the reflective layer 40 is arranged on the non-light incident surface of the SPAD array 30, and is used to reflect the signal light incident on the SPAD array 30 to obtain reflected light with a large angle. The signal light first passes through the filter layer 10, the passband range of the filter layer 10 includes the wavelength of the signal light, and can pass through the filter layer 10, and then the signal light is scattered into large-angle light by the scattering layer 20 for propagation. When the signal light is reflected by the reflective layer 40 and reflected back to the filter layer 10, the incident angle of the signal light is very large at this time, and the passband of the filter layer 10 is blue-shifted, causing the wavelength of the signal light to leave the passband range of the filter film and be in the forbidden band range, and the signal light is reflected by the filter layer 10. The photoelectric detector of the utility model can improve the efficiency of photon detection and has the characteristics of low reflectivity.

[0028] Furthermore, in the photoelectric detector provided by the present invention, the filter layer 10 is a bandpass filter film layer. Furthermore, in the photoelectric detector provided by the present invention, the scattering layer 20 is a grating layer. Further, in the photoelectric detector provided by the present invention, the reflective layer 40 includes a peripheral reflective layer 40 and a bottom reflective layer 40, the peripheral reflective layer 40 is arranged on the four sides of the SPAD array 30, and the bottom reflective layer 40 is arranged on the non-light incident surface of the SPAD array 30; the reflective layer 40 is a metal layer. On the one hand, the metal layer plays an electrical role, and on the other hand, it allows the signal light to reflect and increase the effective optical path of the signal light in the light absorbing material. Further, in the photoelectric detector provided by the present invention, the peripheral reflective layer 40 is a deep trench isolation structure, which is beneficial to reduce optical crosstalk.

[0029] Furthermore, in the photoelectric detector provided by the present invention, the structural parameters of the filter layer 10 include material properties, material thickness, material order, and number of layers. Furthermore, in the photoelectric detector provided by the present invention, the parameters of the bandpass filter film layer include passband range, passband width, and blue shift coefficient of the passband with angle. By changing the structural parameters of the bandpass filter film layer, such as adjusting variables such as material thickness and order, and making specific adjustments to the passband range, passband width, and blue shift coefficient of the passband with angle of the bandpass filter film layer, PDE enhancement of different working center wavelengths and bandwidths can be achieved.

[0030] Furthermore, in the photoelectric detector provided by the utility model, the passband range of the bandpass filter film layer at an incident angle of 0 degree is 940±10nm; the passband range at an incident angle of 15 degrees is 925±10nm; and the passband range at an incident angle of 30 degrees is 890±10nm.

[0031] In the present invention, when the signal light is incident at a small angle, the passband range of the bandpass filter film layer includes the wavelength of the signal light, so the signal light can completely pass through the bandpass filter film layer. After the signal light passes through the filter film, it is scattered by the scattering layer 20 into large-angle light and propagates in the light-absorbing material, which greatly improves the effective optical path of the signal light in the SPAD array 30. When the signal light is reflected by the metal layer and then passes through the bandpass filter film layer, the incident angle of the signal light is very large at this time, and the passband of the bandpass filter film layer is blue-shifted, causing the wavelength of the signal light to leave the passband range of the bandpass filter film layer and be in the forbidden band range. The signal light is reflected by the bandpass filter film layer, and the reflected signal light is absorbed during propagation.

[0032] Figure 2 Schematic diagram of the transmission spectrum of a bandpass filter film layer provided by the utility model, the passband range of the bandpass filter film layer is 940±5nm, such as Figure 3 As shown, as the incident angle increases, the passband range blue shifts, thus meeting the requirements of the photoelectric detector of the utility model for the bandpass filter film. The bandpass filter film layer allows almost all energy incident light to enter the detector, and almost completely prevents the large-angle reflected light generated after reflection by the scattering layer 20 from escaping the detector.

[0033] Figure 3 A schematic diagram comparing the PDE of the photoelectric detector provided by the utility model and the traditional photoelectric detector. Figure 4 A schematic diagram comparing the reflectivity of the photoelectric detector provided by the utility model and the traditional photoelectric detector. Figure 3 , Figure 4It can be seen that within the passband range of the bandpass filter thin film layer, the PDE is increased by nearly 10%, and the reflectivity is reduced by more than 20%. By comparison, it can be seen that the photodetector structure proposed by the utility model can significantly improve its photodetection capability. Furthermore, the utility model integrates the filter layer 10 into the photodetector, which greatly reduces the complexity, volume and cost of the system.

[0034] The utility model also provides a TOF module, including the above-mentioned photoelectric detector and a laser emitter for emitting laser. The signal light emitted by the laser emitter is reflected by the target object and then emitted into the photoelectric detector. The utility model can improve the distance measurement performance of the TOF module.

[0035] The utility model also provides an electronic device, comprising the photoelectric detector as described above, and also comprising a controller for controlling the photoelectric detector to start the function of receiving light. The controller is electrically connected to the photoelectric detector to control the photoelectric detector to start the function of receiving light, and the electronic device has a high photoelectric detection performance.

[0036] In summary, the utility model provides a photoelectric detector, a TOF module and an electronic device. For the photoelectric detector, the signal light first passes through the filter layer, the passband range of the filter layer includes the wavelength of the signal light, and can pass through the filter layer, and then the signal light is scattered into a large angle light through the scattering layer for propagation. When the signal light is reflected by the reflective layer and reflected back to the filter layer, the incident angle of the signal light is very large, and the passband of the filter layer is blue-shifted, causing the wavelength of the signal light to leave the passband range of the filter film and be in the forbidden band range, and the signal light is reflected by the filter layer. The photoelectric detector of the utility model can improve the efficiency of photon detection and has the characteristics of low reflectivity.

[0037] It is understandable that those skilled in the art can make equivalent substitutions or changes based on the technical solution and utility model concept of the utility model, and all these changes or substitutions should fall within the protection scope of the claims attached to the utility model.

Claims

1. A photodetector, comprising: The SPAD array is used to generate a photoelectric effect to convert an optical signal into an electrical signal, and is characterized in that it also includes: A filter layer, disposed on the light incident surface of the SPAD array, the filter layer is used to filter external incident light and only allow signal light of a specific wavelength to pass through and enter the SPAD array; A scattering layer, disposed on the light incident surface of the SPAD array and located between the filter layer and the reflective layer, for changing the incident angle of the signal light in the SPAD array; A reflective layer, disposed on the non-light incident surface of the SPAD array, for reflecting the signal light incident on the SPAD array to obtain reflected light at a large angle; The filter layer is also used to prevent the reflected light at a large angle from passing through and emitting to the outside, so as to reflect the reflected light at a large angle back to the SPAD array.

2. The photodetector according to claim 1, characterized in that: The filter layer is a bandpass filter film layer.

3. The photodetector according to claim 1, characterized in that: The scattering layer is a grating layer.

4. The photodetector according to claim 1, characterized in that: The reflective layer includes a peripheral reflective layer and a bottom reflective layer. The peripheral reflective layer is arranged on the four sides of the SPAD array, and the bottom reflective layer is arranged on the non-light incident surface of the SPAD array. The reflective layer is a metal layer.

5. The photodetector according to claim 4, characterized in that: The peripheral reflective layer is a deep trench isolation structure.

6. The photodetector according to claim 1, characterized in that: The structural parameters of the filter layer include material properties, material thickness, material order, and number of layers.

7. The photodetector according to claim 2, characterized in that: The parameters of the bandpass filter thin film layer include passband range, passband width, and blue shift coefficient of the passband varying with angle.

8. The photodetector according to claim 2, characterized in that: The passband range of the bandpass filter film layer at an incident angle of 0 degrees is 940±10nm; the passband range at an incident angle of 15 degrees is 925±10nm; and the passband range at an incident angle of 30 degrees is 890±10nm.

9. A TOF module, characterized in that: The photoelectric detector comprises the photoelectric detector according to any one of claims 1 to 8, and further comprises a laser emitter for emitting laser.

10. An electronic device, characterized in that: The invention comprises the photoelectric detector according to any one of claims 1 to 8, and further comprises a controller for controlling the photoelectric detector to start a function of receiving light.

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