Infrared detector

Abstract

The present disclosure relates to an infrared detector for realizing infrared ranging based on a time flight principle, comprising: a modulated infrared light source and a detection unit; the modulated infrared light source is used for emitting a detection infrared signal, the detection infrared signal irradiates to a target object and is reflected by the target object to obtain a reflected infrared signal; the detection unit is used for receiving the reflected infrared signal; wherein, based on the detection infrared signal and the reflected infrared signal, the time flight principle is adopted to calculate the distance between the target object and the infrared detector in combination with a phase difference. Thus, a depth detector based on an infrared light source is provided, which is less affected by ambient light and has strong anti-interference ability; and single light source signal ranging is used, which does not depend on high data volume algorithm processing and is not limited by projection speed, and is conducive to real-time imaging; colloidal quantum dots can be used as photosensitive material in the detection unit, and the detection range is wide; and the detection unit can be surface array imaging, and the application scenario is not limited.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of infrared detection, and in particular to an infrared detector. BACKGROUND

[0002] Depth sensing technology is a key technology for constructing a three-dimensional environment model by measuring the distance or depth information between an object and a sensor. The development of depth sensing technology is derived from the demand for three-dimensional perception beyond traditional two-dimensional imaging. With the progress of computer vision and optical technology, depth sensing technology has emerged methods such as binocular stereo vision, structured light, time-of-flight (ToF), and laser radar (LiDAR). Depth sensing technology has a wide range of applications in consumer electronics, autonomous driving, industrial automation, and military fields.

[0003] However, depth sensing technology still has deficiencies such as high cost, performance limitations in complex environments (such as the interference of strong light, rain and fog weather on optical sensors), high computational requirements for data processing, etc. Specifically: first, binocular stereo vision and structured light rely on visible light, and are easily disturbed by visible light components in the environment light during imaging, and have weak anti-interference ability; and rely on high data volume algorithm processing, are limited by projection speed, and have poor imaging real-time performance; second, laser radar uses laser as a light source, which is harmful to the human eye, and uses mechanical scanning, which is slow and has poor imaging real-time performance; third, existing ToF technology mainly relies on visible light sources, which is easily disturbed by visible light components in the environment light, and has weak anti-interference ability. The ToF technology using infrared light sources is based on InGaAs traditional bulk materials, which has complex preparation process, high cost, large flip-chip volume, poor integration, and is affected by material properties, with a cutoff wavelength of only 1700nm, low infrared detection efficiency, and cannot detect longer wavelength light sources; fourth, existing depth cameras based on time flight need to rely on polarized light and lens reflection optical systems, which have complex structures and limited application scenarios. SUMMARY

[0004] To solve or at least partially solve the above technical problems, the present disclosure provides an infrared detector.

[0005] The present disclosure provides an infrared detector, which realizes infrared ranging based on the time flight principle, and comprises a modulated infrared light source and a detection unit.

[0006] The modulated infrared light source is used to emit a detection infrared signal, which irradiates to a target object and is reflected by the target object to obtain a reflected infrared signal.

[0007] The detection unit is used to receive the reflected infrared signal.

[0008] The distance between the target object and the infrared detector is obtained by using time flight principle and combining phase difference based on the detection infrared signal and the reflection infrared signal.

[0009] Optionally, the detection unit comprises a readout circuit and a photoelectric detection structure.

[0010] The photoelectric detection structure is arranged in an array on one side of the readout circuit and directly coupled with the readout circuit.

[0011] Optionally, the photoelectric detection structure comprises an infrared colloidal quantum dot layer.

[0012] The infrared colloidal quantum dot layer is formed by a liquid phase processing method.

[0013] Optionally, the photoelectric detection structure further comprises a first metal electrode and a second metal electrode.

[0014] The first metal electrode and the second metal electrode are both located between the infrared colloidal quantum dot layer and the readout circuit and oppositely arranged in a plane parallel to the plane where the readout circuit is located.

[0015] Optionally, the photoelectric detection structure is a light guide type detection structure, the thickness of the first metal electrode and the second metal electrode is 5-100 nanometers, and the thickness of the infrared colloidal quantum dot layer is 100-1000 nanometers.

[0016] Optionally, the photoelectric detection structure further comprises a first electrode, an N-type doped layer, a P-type doped layer and a second electrode.

[0017] In a direction away from the readout circuit, the first electrode, the N-type doped layer, the infrared colloidal quantum dot layer, the P-type doped layer and the second electrode are stacked.

[0018] Optionally, the thickness of the first electrode and the second electrode is 5-100 nanometers, and the thickness of the N-type doped layer and the P-type doped layer is 50-200 nanometers.

[0019] The thickness of the infrared colloidal quantum dot layer is 100-500 nanometers, and the photoelectric detection structure is a photovoltaic type detection structure; or the thickness of the infrared colloidal quantum dot layer is 500-1000 nanometers, and the photoelectric detection structure is an avalanche photodetection structure.

[0020] Optionally, the infrared colloidal quantum dot layer comprises at least one of lead sulfide, lead selenide, lead telluride, cadmium sulfide, cadmium selenide, mercury telluride, mercury selenide, mercury sulfide, silver telluride, silver sulfide and silver selenide.

[0021] Optionally, the infrared detector further comprises a controller, and the modulated infrared light source and the detection unit are connected to the controller respectively.

[0022] The controller is configured to control the modulated infrared light source to emit the modulated detection infrared signal, and the detection infrared signal has an initial phase.

[0023] The controller is further configured to calculate the distance based on the initial phase and a phase difference between the detection infrared signal and the reflected infrared signal.

[0024] Optionally, the frequency of the modulated infrared light source is 10-300 MHz, and the corresponding detection distance is 0.5-15 m.

[0025] The technical solution provided by the present disclosure has the following advantages compared with the prior art:

[0026] The infrared detector provided by the present disclosure comprises a modulated infrared light source and a detection unit. The modulated infrared light source is configured to emit a detection infrared signal, and the detection infrared signal irradiates a target object and is reflected by the target object to obtain a reflected infrared signal. The detection unit is configured to receive the reflected infrared signal. Based on the detection infrared signal and the reflected infrared signal, the distance between the target object and the infrared detector is calculated by using the time-of-flight principle and combining the phase difference. Thus, a depth detector based on an infrared light source is provided, which is less affected by ambient light and has strong anti-interference capability. The distance is measured by using a single light source signal, and the depth detector does not rely on high data volume algorithm processing and is not limited by projection speed, which is beneficial for real-time imaging. Colloidal quantum dots can be used as the photosensitive material in the detection unit, and the detection range is wide. The detection unit can be used for face array imaging, and the application scenarios are not limited. BRIEF DESCRIPTION OF DRAWINGS

[0027] The accompanying drawings, which are incorporated into and form a part of the specification, illustrate embodiments consistent with the present disclosure and, together with the description, serve to explain the principles of the disclosure.

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure or the prior art, the accompanying drawings needed to be used in the embodiments or the prior art description will be briefly introduced. Obviously, for those skilled in the art, other drawings can also be obtained without creative labor based on these drawings.

[0029] Figure 1 A structural schematic diagram of an infrared detector provided by the present disclosure is shown in the figure.

[0030] Figure 2 A structural schematic diagram of a photoelectric detection structure provided by the present disclosure is shown in the figure.

[0031] Figure 3Another structural schematic diagram of a photoelectric detection structure provided by an embodiment of the present disclosure is provided.

[0032] Figure 4 A ranging principle schematic diagram of an infrared detector provided by an embodiment of the present disclosure is provided. DETAILED DESCRIPTION

[0033] In order to more clearly understand the above-mentioned purposes, features and advantages of the present disclosure, the solutions of the present disclosure will be further described below. It should be noted that the embodiments of the present disclosure and the features in the embodiments can be combined with each other without conflict.

[0034] In the following description, a large number of specific details are set forth in order to facilitate a thorough understanding of the present disclosure, but the present disclosure can also be implemented in other different manners from those described herein; obviously, the embodiments described in the specification are only a part of the embodiments of the present disclosure, rather than all the embodiments.

[0035] In the infrared detector provided by the embodiment of the present disclosure, the time of flight (ToF) technology is used to modulate the infrared light source as a detection light source, which is less harmful to the human eye, and is less affected by the environment visible light and the environment infrared light, and has strong anti-interference ability. In addition, unlike binocular vision based on parallax calculation and structured light based on projection pattern deformation analysis, since the ToF technology measures the distance by receiving a single light source signal, it does not rely on high data volume algorithm processing and is not limited by the projection speed. The detection unit uses a surface array imaging chip to directly image without using mechanical scanning, and has strong imaging real-time performance. At the same time, in the detection unit, the colloidal quantum dots are used as infrared photosensitive materials, which can be directly coupled with the readout circuit, and the preparation process is simple, the cost is low, the infrared response spectrum is wide, the colloidal quantum dots are adjustable based on quantum confinement effect, the infrared detection efficiency is high, the infrared signal after 1700nm can be detected, the infrared light sources with wavelengths of 1550nm, 2050nm and other wavelengths can be used for detection, and the application range is wide. In addition, since the detection unit can use a surface array imaging chip to directly image, it does not need to rely on the optical system imaging through the polarizer and the lens reflection, the structure can be simplified, and the application scene is not limited.

[0036] The structure and working principle of the infrared detector provided by the embodiment of the present disclosure will be exemplarily described below in combination with the drawings.

[0037] Exemplarily, Figure 1 A structural schematic diagram of an infrared detector provided by an embodiment of the present disclosure is provided, which realizes infrared ranging based on the time flight principle. Referring to Figure 1The infrared detector 10 can include: a modulated infrared light source 11 and a detection unit 12; the modulated infrared light source 11 is used to emit a detection infrared signal, the detection infrared signal irradiates to the target object 01, and is reflected by the target object 01 to obtain a reflected infrared signal; the detection unit 12 is used to receive the reflected infrared signal; wherein, based on the detection infrared signal and the reflected infrared signal, the distance between the target object 01 and the infrared detector 10 is obtained by calculation based on the time flight principle combined with the phase difference.

[0038] The modulated infrared light source 11 can output the detection infrared signal, the detection infrared signal is a modulated infrared signal, and has a certain initial phase. For example, by modulating the light intensity of the infrared light source, a modulated infrared light source with a sine or square wave shape (the maximum value of the wave shape is 100% of the original infrared light intensity, and the minimum value of the wave shape is 10%-40% of the original infrared light source, and the frequency of the modulated light source is 10MHz-300MHz) can be obtained. After the emitted modulated infrared signal irradiates to the target object 01 in the scene, the infrared light is reflected back, and the reflected infrared signal is received by the detection unit 12. Because the distance between the object and the infrared detector 10 is different, there is a phase difference between the reflected infrared signal received by the detection unit 12 and the detection infrared signal emitted by the modulated infrared light source 11. By calculating the phase difference, the distance between the target object 01 and the infrared detector 10 can be obtained by calculation combined with the frequency of the modulated light source and the speed of light.

[0039] The infrared detector 10 provided by the embodiment of the present disclosure realizes distance measurement based on the time flight principle, uses the detection infrared signal emitted by the modulated infrared light source 11 as the detection light source, can avoid the influence of the environment visible light, and has strong anti-interference ability and is less affected by the environment infrared light.

[0040] In some embodiments, continuing to refer to Figure 1 In the infrared detector 10, the detection unit 12 includes a readout circuit 120 and a photoelectric detection structure 122; the photoelectric detection structure 122 is arranged in an array on one side of the readout circuit 120 and is directly coupled with the readout circuit 120.

[0041] The photoelectric detection structure 122 is used to generate a corresponding photoelectric signal in response to the received reflected infrared signal and transmit the photoelectric signal to the readout circuit 120; correspondingly, the readout circuit 120 is used to read out the photoelectric signal and transmit the photoelectric signal to a subsequent circuit for further processing to obtain a detection result. The arrayed photoelectric detection structure 122 enables the detection unit to detect the reflected infrared signal based on the area array structure, so that the infrared detector 10 can directly image based on the area array detection structure, without relying on the optical system imaging through the polarizer and the lens, thereby simplifying the structure of the infrared detector 10 and expanding the application scenarios of the infrared detector 10.

[0042] It should be noted that,Figure 1 The array of the photodetecting structure 122 is only exemplarily shown, and in actual applications, the array arrangement mode can include 128*128, 320*256, 640*512, 1280*1024, etc., which is not limited herein.

[0043] In some embodiments, Figure 2 A structural schematic diagram of a photodetecting structure provided by an embodiment of the present disclosure, Figure 3 A structural schematic diagram of another photodetecting structure provided by an embodiment of the present disclosure. In Figure 1 Reference is made to Figure 2 or Figure 3 The photodetecting structure 122 includes an infrared colloidal quantum dot layer 20; the infrared colloidal quantum dot layer 20 is formed by a liquid phase processing mode.

[0044] In the infrared colloidal quantum dot layer 20, colloidal quantum dots are used as infrared photosensitive materials, which can be directly coupled with a readout circuit, has a simple preparation process, low cost, a wide infrared response spectrum, and high infrared detection efficiency. Based on the quantum confinement effect, the colloidal quantum dot band can be adjusted, and the infrared signal after 1700 nm can be detected. The infrared light source with a wavelength of 1550 nm, 2050 nm or other wavelengths can be used for detection, and the application range is wide.

[0045] In the embodiment of the present disclosure, the colloidal quantum dots are directly coupled with the readout circuit, the synthesis process of the colloidal quantum dots is simple, the liquid material is converted into a solid functionalized film by a low-cost liquid phase processing process, and expensive flip-chip bonding, molecular beam epitaxy and other processes are not needed, which greatly reduces the material processing cost, and a high-sensitivity, wide-spectrum infrared detector can be formed. At the same time, the readout circuit is one of a CCD or a CMOS, the colloidal quantum dots are used as photosensitive materials to prepare the detector, the band range of the quantum dots is accurately adjusted by changing the reaction temperature, reaction time, reactant ratio and other parameters in the synthesis process of the quantum dots, the detection band of the detector is widened, and the detector can match infrared light sources with different wavelengths. Specifically, different wavelengths of infrared light sources can be needed for different application scenarios, the band of the traditional bulk material is difficult to adjust, and it is difficult to match the light source to achieve a good signal-to-noise ratio, while the quantum dot technology can synthesize quantum dots matched with the band of the light source, and the application scenarios are widened.

[0046] In some embodiments, continuing to refer to Figure 2 The photodetecting structure 122 is a light guide type detection structure, which has a simple structure process and low cost. Exemplarily, the photodetecting structure 122 further includes a first metal electrode 21 and a second metal electrode 22; the first metal electrode 21 and the second metal electrode 22 are both located between the infrared colloidal quantum dot layer 20 and the readout circuit 120, and are oppositely arranged in a plane parallel to the plane where the readout circuit 120 is located.

[0047] The first metal electrode 21 and the second metal electrode 22 can be made of the same material in the same process; the infrared colloidal quantum dot layer 20 is filled between the first metal electrode 21 and the second metal electrode 22 and covers the side of the electrodes away from the readout circuit 120.

[0048] For example, the metal electrode can be one or more of platinum, gold, silver, copper, aluminum, and chromium, which are not limited herein.

[0049] In some embodiments, the thickness of the first metal electrode 21 and the second metal electrode 22 is 5 nm to 100 nm, and the thickness of the infrared colloidal quantum dot layer 20 is 100 nm to 1000 nm, to meet the photoelectric conversion requirement in infrared detection and the transmission requirement of photoelectric signals.

[0050] For example, the thickness of the metal electrode can be 5 nm, 100 nm, 50 nm, 40 nm to 60 nm, or other thickness values or ranges; the thickness of the infrared colloidal quantum dot layer 20 can be 100 nm, 1000 nm, 500 nm, 400 nm to 600 nm, or other thickness values or ranges, which are not limited herein.

[0051] In some embodiments, continuing to refer to Figure 3 The infrared detector can be a photovoltaic detector or an avalanche photodetector, wherein the photoelectric detection structure 122 further includes a first electrode 23, an N-type doped layer 24, a P-type doped layer 25, and a second electrode 26; in the direction away from the readout circuit 120 (for example, the direction from bottom to top in the shown orientation), the first electrode 23, the N-type doped layer 24, the infrared colloidal quantum dot layer 20, the P-type doped layer 25, and the second electrode 26 are stacked. Figure 3

[0052] The N-type doped layer 24, the infrared colloidal quantum dot layer 20, and the P-type doped layer 25 combine to form a PN junction structure, so that there is a built-in electric field inside. The built-in electric field can effectively reduce the dark current of the detector, thereby improving the sensitivity, resolution, and signal-to-noise ratio of the detector and enhancing the performance of the detector.

[0053] In some embodiments, continuing to refer to Figure 3 The thickness of the first electrode 23 and the second electrode 26 is 5 nm to 100 nm, and the thickness of the N-type doped layer 24 and the P-type doped layer 25 is 50 nm to 200 nm; the thickness of the infrared colloidal quantum dot layer 20 is 100 nm to 500 nm, and the photoelectric detection structure 122 is a photovoltaic detection structure; or the thickness of the infrared colloidal quantum dot layer 20 is 500 nm to 1000 nm, and the photoelectric detection structure 122 is an avalanche photodetector. ​

[0054] Specifically, the difference between the photovoltaic type detector and the avalanche photodetector lies in that the intrinsic quantum dot layer (i.e. the infrared colloidal quantum dot layer 20) of the avalanche photodetector is thicker (e.g. > 500 nm) than that of the photovoltaic type detector, and the working voltages of the two are different, the working voltage of the photovoltaic type detector is 0-5V, and the working voltage of the avalanche photodetector needs to be > 14V. The above-mentioned readout circuit coupled with the colloidal quantum dot and the controller (see later) and the modulated infrared light source together constitute a ToF infrared detector.

[0055] In some embodiments, continuing to refer to Figure 2 or Figure 3 , the infrared colloidal quantum dot layer 20 includes at least one of lead sulfide (PbS), lead selenide (PbSe), lead telluride (PbTe), cadmium sulfide (CdS), cadmium selenide (CdSe), mercury telluride (HgTe), mercury selenide (HgSe), mercury sulfide (HgS), silver telluride (Ag2Te), silver sulfide (Ag2S), and silver selenide (Ag2Se).

[0056] In some embodiments, continuing to refer to Figure 3 , the first electrode 23 can be a metal electrode, and the specific material can include one or more of platinum, gold, silver, copper, aluminum, and chromium; the second electrode 26 can be a transparent electrode, and the specific material can include one of indium tin oxide (ITO) and fluorine-doped tin dioxide (FTO).

[0057] In some embodiments, continuing to refer to Figure 3 , the N-type doped layer 24 can include one of bismuth selenide (Bi2Se3), bismuth sulfide (Bi2S3), bismuth telluride (Bi2Te3), zinc oxide (ZnO), cadmium selenide (CdSe), titanium dioxide (TiO2), 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), methyl butyrate (PCBM), and the same N-type quantum dot film as the intrinsic colloidal quantum dot; the P-type doped layer 25 can include one of silver telluride (Ag2Te), poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS), poly(3-hexylthiophene) (P3HT), poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS), 2,2',7,7'-tetrakis[N,N-bis(4-methoxyphenyl)amino]-9,9'-spirobifluorene (spiro-OMeTAD), polytriazylamine (PTAA), nickel oxide (NiO x ), zinc telluride (ZnTe), C 60 , and the same P-type quantum dot as the intrinsic colloidal quantum dot.

[0058] In some embodiments, the preparation process of the infrared detector can include the following steps:

[0059] First, clean the readout circuit. Specifically, clean the readout circuit with cleaning solutions such as acetone, isopropyl alcohol, alcohol, deionized water, etc.

[0060] Second, modify the bottom electrode (including one of dry etching, wet etching, and peeling to achieve patterning) using a lithography process (such as one of ultraviolet lithography, laser direct writing, and electron beam exposure), and the thickness of the bottom electrode is 5 nm-100 nm. Specifically, the bottom electrode can be understood as the first metal electrode and the second metal electrode in Figure 2 , or include the first electrode in Figure 3 .

[0061] Third, couple the colloidal quantum dots.

[0062] Specifically, for the light guide type detector, this step can specifically include: preparing the colloidal quantum dots onto the readout circuit using one of film forming methods such as spin coating, drop coating, spraying, blade coating, and evaporation, and the film thickness is 100 nm-1000 nm.

[0063] For the photovoltaic type detector, first, prepare the N-type doped layer onto the bottom electrode using one of film forming methods such as drop coating, spin coating, spraying, blade coating, and evaporation, and the film thickness is 50 nm-200 nm; then, prepare the intrinsic colloidal quantum dots onto the N-type doped layer using one of film forming methods such as spin coating, drop coating, spraying, blade coating, and evaporation, and the film thickness is 100 nm-500 nm; then, prepare the P-type doped layer onto the intrinsic colloidal quantum dots using one of film forming methods such as drop coating, spin coating, spraying, blade coating, and evaporation, and the film thickness is 50 nm-200 nm; finally, prepare the transparent electrode onto the P-type doped layer using one of film forming methods such as thermal evaporation, magnetron sputtering, and atomic layer deposition, and the film thickness is 5 nm-100 nm.

[0064] For the avalanche photodetector, first, prepare the N-type doped layer onto the bottom electrode using one of film forming methods such as drop coating, spin coating, spraying, blade coating, and evaporation, and the film thickness is 50 nm-200 nm; then, prepare the intrinsic colloidal quantum dots onto the N-type doped layer using one of film forming methods such as spin coating, drop coating, spraying, blade coating, and evaporation, and the film thickness is 500 nm-1000 nm; then, prepare the P-type doped layer onto the intrinsic colloidal quantum dots using one of film forming methods such as drop coating, spin coating, spraying, blade coating, and evaporation, and the film thickness is 50 nm-200 nm; finally, prepare the transparent electrode onto the P-type doped layer using one of film forming methods such as thermal evaporation, magnetron sputtering, and atomic layer deposition, and the film thickness is 5 nm-100 nm.

[0065] In this way, three different types of infrared detectors can be formed.

[0066] In some embodiments,Figure 4 The ranging principle of the infrared detector provided by the embodiment of the present disclosure is shown in the figure. Referring to Figure 4 and Figure 1 , the infrared detector 10 further comprises a controller 13, and the modulated infrared light source 11 and the detection unit 12 are respectively connected to the controller 13; the controller 13 is configured to control the modulated infrared light source 11 to emit a modulated detection infrared signal, and the detection infrared signal has an initial phase; the controller 13 is further configured to calculate the distance based on the initial phase and the phase difference of the reflected infrared signal.

[0067] Specifically, the modulated infrared light source 11 in a sine or square wave form is obtained by modulating the light intensity of the infrared light source. The maximum value of the wave form is 100% of the original infrared light intensity, and the minimum value of the wave form is 10%-40% of the original infrared light source. The frequency of the modulated light source is 10MHz-300MHz.

[0068] The modulated infrared signal emitted by the modulated infrared light source 11 is reflected back after irradiating the object in the scene, forming a reflected infrared signal, which is received by the area array detection structure of the detection unit. At this time, due to the different distances between the object and the detector, the wave form of the reflected infrared signal received by the detection unit and the wave form of the detection infrared signal emitted by the modulated infrared light source exist a phase difference , referring to Figure 4 , the distance between the target object and the infrared detector can be obtained by calculating the phase difference.

[0069] The specific calculation method is: through the controller 13, each pixel point in the detection unit 12 is sampled four times, and the phase difference between each sampling and the modulated infrared light source 11 is 0°, 180°, 90° and 270° respectively. Since the signal intensity received by the pixel changes periodically, and the start time and end time of the four samplings are different, the signal intensity collected is not completely the same, and the sampled signals are respectively denoted as , , , (as shown in Figure 4 , only taking square wave as an example, and actually it can also be sine wave), the phase difference between the infrared signal received by each pixel point and the modulated infrared light source signal can be calculated , and the specific calculation formula is as follows:

[0070]

[0071] The phase difference is converted into distance, and the three-dimensional information of the imaged object can be obtained, and the specific conversion formula is as follows:

[0072]

[0073] wherein c is the speed of light, f is the frequency of the modulated infrared light source.

[0074] Meanwhile, in order to improve the signal-to-noise ratio, the detector can integrate the signals of multiple modulation periods (for example, n periods), and for the phase difference , the calculation formula becomes:

[0075]

[0076] The multi-period integration can effectively suppress random noise and improve the accuracy of distance calculation.

[0077] It should be noted that if the phase difference between the signal received by the pixel point and the signal of the modulated infrared light source exceeds , the calculation of the distance will be erroneous, and therefore the effective distance that can be detected by the detector is , that is, the distance corresponding to the phase difference of , and the frequency of the modulated infrared light source is 10 MHz-300 MHz, and the corresponding detection distance is 0.5 m-15 m.

[0078] In some embodiments, the frequency of the modulated infrared light source 11 is 10 MHz to 300 MHz, and the corresponding detection distance is 0.5 m to 15 m, to ensure effective detection.

[0079] In the infrared detector provided by the embodiments of the present disclosure, based on the infrared colloidal quantum dots, the infrared detector 10 can be directly coupled with the silicon-based circuit, the modulated infrared light source is integrated in the imaging circuit, the modulated light source is irradiated onto the target object and returned, is detected by the infrared detector, the phase difference is measured, and the distance from the object to the detector is calculated, thereby realizing the time-of-flight (ToF) depth sensing.

[0080] It should be noted that, in the present document, relational terms such as“first” and“second”, and the like, are used solely to distinguish one entity or action from another entity or action, without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms“comprises”,“comprising”, or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without limitation, an element preceded by“comprises... a” does not, without more constraints, foreclose the existence of additional identical elements in the process, method, article, or apparatus that comprises the element.

[0081] The foregoing is merely illustrative of the various implementations of the present disclosure and the general principles thereof. Numerous modifications can be made to these illustrations, and equivalents can be substituted therefor, without departing from the scope of the present disclosure. The specific embodiments commensurate with the specific application are intended to be illustrative only and not limiting of the scope of the application as set forth in the following claims.

Claims

1. An infrared detector, characterized by The infrared detector comprises a modulated infrared light source and a detection unit, and realizes infrared ranging based on the time flight principle. The modulated infrared light source is used for emitting a detection infrared signal, the detection infrared signal is irradiated to a target object and is reflected by the target object to obtain a reflected infrared signal. The detection unit is used for receiving the reflected infrared signal. The distance between the target object and the infrared detector is obtained by calculating the time flight principle combined with the phase difference based on the detection infrared signal and the reflected infrared signal. The detection unit comprises a readout circuit and a photoelectric detection structure, the photoelectric detection structure is arranged in an array on one side of the readout circuit and is directly coupled with the readout circuit. The photoelectric detection structure comprises an infrared colloidal quantum dot layer, the infrared colloidal quantum dot layer is formed by a liquid phase processing method. The photoelectric detection structure further comprises a first metal electrode and a second metal electrode, the first metal electrode and the second metal electrode are both located between the infrared colloidal quantum dot layer and the readout circuit and are oppositely arranged in a plane parallel to the plane where the readout circuit is located; or the photoelectric detection structure further comprises a first electrode, an N-type doped layer, a P-type doped layer and a second electrode, the first electrode, the N-type doped layer, the infrared colloidal quantum dot layer, the P-type doped layer and the second electrode are stacked in a direction away from the readout circuit. The N-type doped layer, the infrared colloidal quantum dot layer and the P-type doped layer combine to form a PN junction structure, so that there is a built-in electric field in the photoelectric detection structure; the built-in electric field is used for reducing the dark current of the infrared detector, improving the sensitivity, resolution and signal-to-noise ratio of the infrared detector and enhancing the performance of the infrared detector.

2. The infrared detector of claim 1, wherein, The photoelectric detection structure is a photoconductive type detection structure, the thickness of the first metal electrode and the second metal electrode is 5 nanometers to 100 nanometers, and the thickness of the infrared colloidal quantum dot layer is 100 nanometers to 1000 nanometers.

3. The infrared detector of claim 1, wherein, The thickness of the first electrode and the second electrode is 5 nanometers to 100 nanometers, and the thickness of the N-type doped layer and the P-type doped layer is 50 nanometers to 200 nanometers. The thickness of the infrared colloidal quantum dot layer is 100 nanometers to 500 nanometers, and the photoelectric detection structure is a photovoltaic type detection structure; or the thickness of the infrared colloidal quantum dot layer is 500 nanometers to 1000 nanometers, and the photoelectric detection structure is an avalanche photoelectric detection structure.

4. The infrared detector of claim 1, wherein, The infrared colloidal quantum dot layer comprises at least one of lead sulfide, lead selenide, lead telluride, cadmium sulfide, cadmium selenide, mercury telluride, mercury selenide, mercury sulfide, silver telluride, silver sulfide and silver selenide.

5. The infrared detector of claim 1, wherein, The infrared detector further comprises a controller, and the modulated infrared light source and the detection unit are respectively connected to the controller. The controller is used for controlling the modulated infrared light source to emit the modulated detection infrared signal, and the detection infrared signal has an initial phase. The controller is further used for calculating the distance based on the initial phase and the phase difference of the reflected infrared signal.

6. The infrared detector according to any one of claims 1 to 5, characterized in that The frequency of the modulated infrared light source is 10-300 MHz, and the corresponding detection distance is 0.5-15 m.

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