Infrared polarization detector and device

Abstract

The invention discloses an infrared polarization detector and device, and relates to the photoelectric detection technology. The detector chip (2) is electrically connected with the reading circuit (1) through an indium column (5), a polarization grating (4) is arranged on one surface, far away from the reading circuit (1), of the detector chip, and a pixel array structure (3) is arranged on the other surface, close to the reading circuit (1), of the detector chip; the relative positions of the pixel array structures (3) and the polarization gratings (4) are in one-to-one correspondence. Through the design of the n-type region of the polarization grating structure, the crosstalk of adjacent pixel signals can be blocked, so that the response value when the light transmission axes of the polarizer and the polarization grating are vertical is reduced, and the extinction ratio of the infrared polarization detector is improved.

Description

Technical Field

[0001] The present application relates to the field of photoelectric detection technology, and in particular to an infrared polarization detector and device. Background Art

[0002] Polarized infrared detectors integrate micro-nano polarization devices with infrared detector chips, integrate polarizers with different polarization directions on the focal plane, and use them one by one with the pixels of the detector. Different pixels detect different polarization directions. The extinction ratio is an important indicator for evaluating the performance of polarized infrared detectors. The higher the extinction ratio, the higher the recognition of the target by the polarized infrared detector.

[0003] The extinction ratio of infrared detectors is significantly reduced after the integration of polarization devices, which has always been a key indicator restricting the application of infrared detectors. Improving the extinction ratio of polarized infrared detectors is a very necessary task. The preparation process of polarization devices will affect the extinction ratio of the polarization device itself, but the process improvement has little effect on improving the extinction ratio of polarized infrared detectors. Summary of the invention

[0004] The embodiments of the present application provide an infrared polarization detector and a device, which improve the extinction ratio of the polarization infrared detector by reducing the crosstalk of the detector itself and the crosstalk of the polarization structure.

[0005] The present application embodiment provides an infrared polarization detector, comprising:

[0006] Readout circuit 1;

[0007] The detector chip 2 is electrically connected to the readout circuit 1 through an indium column 5, wherein a polarization grating 4 is arranged on one side of the detector chip away from the readout circuit 1, and a pixel array structure 3 is arranged on the other side of the detector chip close to the readout circuit 1, and the pixel array structure 3 and the polarization grating 4 are in one-to-one correspondence in relative position.

[0008] Optionally, the pixel array structure 3 includes:

[0009] The first substructure 31_ is in a grid structure on the other side of the readout circuit 1;

[0010] The second substructure 32 is an array structure, which is arranged in the grid structure of the first substructure 31 and is located in the area within the projection of the polarization grating 4 on the other side of the readout circuit 1 .

[0011] Optionally, a projection of any of the polarization gratings 4 on the other side of the readout circuit 1 is located in a corresponding grid structure, and there is no overlap between the projection and the corresponding grid structure, and the projection includes the second substructure 32 .

[0012] Optionally, the second substructure is located within the projection range of any pixel of the polarization grating 4 on the other side of the readout circuit 1 .

[0013] Optionally, the cross-section of the second substructure is circular.

[0014] Optionally, the detector chip 2 is a P-type mercury cadmium telluride detector, and the pixel array structure 3 is an n-type implantation region.

[0015] The embodiment of the present application further provides an infrared polarization detection device, including the infrared polarization detector as described above.

[0016] The embodiments of the present application improve the extinction ratio of the polarized infrared detector by reducing the crosstalk of the detector itself and the crosstalk of the polarization structure.

[0017] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present application. Also, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0019] Figure 1 This is a schematic diagram of an infrared integrated polarization detector according to an embodiment of the present application;

[0020] Figure 2 A cross-sectional view of an infrared integrated polarization detector according to an embodiment of the present application;

[0021] Figure 3 This is a schematic diagram of the relative arrangement of the integrated polarization infrared detector pixel and the polarization grating of the infrared integrated polarization detector in an embodiment of the present application. DETAILED DESCRIPTION

[0022] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0023] The extinction ratio is defined as the ratio of the maximum response voltage of the detector when the transmission axes of the polarizer and the polarization grating on the micro-nano polarization integrated detector chip are parallel to the minimum response voltage when the transmission axes are perpendicular. Theoretically, the response value of the pixel is the largest when the transmission axes of the polarizer and the polarization grating are parallel; theoretically, when the transmission axes of the polarizer and the polarization grating are perpendicular, the response value of the pixel tends to be infinitely small. In actual operation, the signals of adjacent pixels will crosstalk to the pixel, reducing the extinction ratio of the pixel.

[0024] Taking into account the wavelength characteristics and process difficulty of the medium-wave infrared detector, the polarization grating line width generally has a good extinction ratio when it is hundreds of nanometers. However, the extinction ratio of the infrared polarization detector after the actual integration process is much smaller than the extinction ratio of the designed grating structure, mainly due to the following reasons:

[0025] 1. The medium wave signal will diffract when passing through the grating structure, causing crosstalk between adjacent pixels and reducing the extinction ratio of the infrared polarization detector;

[0026] 2. Electrical crosstalk between adjacent pixels affects the extinction ratio of the infrared polarization detector;

[0027] 3. The influence of stray light on the test system, Dewar structure, detector surface and body reduces the extinction ratio of the infrared polarization detector.

[0028] The solution of the present application is improved based on the existing infrared integrated polarization detector structure. Specifically, the embodiment of the present application provides an infrared polarization detector, such as Figure 1 , 2 As shown, including:

[0029] Readout circuit 1;

[0030] The detector chip 2 is electrically connected to the readout circuit 1 through an indium column 5, wherein a polarization grating 4 is arranged on one side of the detector chip away from the readout circuit 1, and a pixel array structure 3 is arranged on the other side of the detector chip close to the readout circuit 1, and the pixel array structure 3 and the polarization grating 4 are in one-to-one correspondence in relative position.

[0031] In some embodiments, Figure 3 As shown, the pixel array structure 3 includes:

[0032] The first substructure 31 is in a grid structure on the other side of the readout circuit 1;

[0033] The second substructure 32 is an array structure, which is arranged in the grid structure of the first substructure 31 and is located in the area within the projection of the polarization grating 4 on the other side of the readout circuit 1. In a specific example, the gratings of the pixel array structure 3 are arranged in 2×2 to form a polarization super pixel specification.

[0034] In some embodiments, Figure 3 As shown, the projection of any polarization grating 4 on the other side of the readout circuit 1 is located in the corresponding grid structure, and there is no overlap between its projection and the corresponding grid structure, and the projection includes the second substructure 32. As an example, Figure 3 As shown, the projection of any pixel of the polarization grating 4 on the other side of the readout circuit 1 is a rectangular structure, and in a specific example, it can also be a structure of other shapes, which is not specifically limited.

[0035] In some embodiments, Figure 3 As shown, the second substructure 32 is located within the projection range of any pixel of the polarization grating 4 on the other side of the readout circuit 1 .

[0036] In some embodiments, Figure 3 As shown, the cross section of the second substructure is circular within the projection range of the other surface of the readout circuit 1 , and in a specific example, it may also be a structure of other shapes, which is not specifically limited.

[0037] In some embodiments, the detector chip 2 is a P-type mercury cadmium telluride detector, and the pixel array structure 3 is an n-type implantation region.

[0038] The solution of the present application optimizes the design of the polarization grating structure, which can reduce the electrical crosstalk between pixels. By designing the n-type region of the polarization grating structure, the signal crosstalk between adjacent pixels can be blocked, thereby reducing the response value when the transmission axes of the polarizer and the polarization grating are perpendicular, and improving the extinction ratio of the infrared polarization detector.

[0039] The embodiment of the present application further provides an infrared polarization detection device, including the infrared polarization detector as described above.

[0040] It should be noted that in the various embodiments of the present application, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "includes a ..." does not exclude the presence of other identical elements in the process, method, article or device including the element.

[0041] The serial numbers of the above-mentioned embodiments of the present application are for description only and do not represent the advantages or disadvantages of the embodiments.

[0042] The embodiments of the present application are described above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present application, ordinary technicians in this field can also make many forms without departing from the purpose of the present application and the scope of protection of the claims, all of which are within the protection of the present application.

Claims

1. An infrared polarization detector, characterized in that: include: Readout circuit (1); A detector chip (2) is electrically connected to the readout circuit (1) via an indium column (5), wherein a polarization grating (4) is arranged on one side of the detector chip away from the readout circuit (1), and a pixel array structure (3) is arranged on the other side of the detector chip close to the readout circuit (1), and the pixel array structure (3) and the polarization grating (4) are in one-to-one correspondence in relative position.

2. The infrared polarization detector according to claim 1, characterized in that: The pixel array structure (3) comprises: A first substructure (31) is in a grid structure on the other side of the readout circuit (1); The second substructure (32) is an array structure, which is arranged in the grid structure of the first substructure (31) and is located in a region within the projection of the polarization grating (4) on the other side of the readout circuit (1).

3. The infrared polarization detector according to claim 2, characterized in that: The projection of any of the polarization gratings (4) on the other side of the readout circuit (1) is located in the corresponding grid structure, and there is no overlap between the projection and the corresponding grid structure, and the projection contains the second substructure (32).

4. The infrared polarization detector according to claim 3, characterized in that: The second substructure is located within the projection range of any pixel of the polarization grating (4) on the other side of the readout circuit (1).

5. The infrared polarization detector according to claim 4, characterized in that: The second substructure has a circular cross section.

6. The infrared polarization detector according to claim 1, characterized in that: The detector chip (2) is a P-type mercury cadmium telluride detector, and the pixel array structure (3) is an n-type injection region.

7. An infrared polarization detection device, characterized in that: It comprises the infrared polarization detector as described in any one of claims 1 to 7.

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