Infrared imaging system and thermal imager

Abstract

The utility model provides an infrared imaging system and a thermal imager. The infrared imaging system comprises an infrared lens, a detector packaging structure and a detector photosensitive chip. The detector photosensitive chip is packaged in the detector packaging structure; the infrared lens is used for receiving infrared light of a target object to be detected and converging the infrared light on the detector photosensitive chip after the infrared light passes through the light passing area of the detector packaging structure; a light transmission area of the detector packaging structure is provided with a phase change material layer which has an insulation state and a metal state. When the temperature is lower than the phase change temperature, the light is transmitted in an insulated state so that the light can enter the detector packaging structure, and when the temperature is higher than the phase change temperature, the light is reflected in a metal state so that the light can be prevented from entering the detector packaging structure. According to the infrared imaging system and the thermal imager provided by the invention, the infrared detector can be prevented from being burnt by a high-temperature object, and meanwhile, the normal imaging function of the infrared detector is not influenced.

Description

Technical Field

[0001] This application relates to the technical field of infrared devices, and particularly to an infrared imaging system and a thermal imager. Background Art

[0002] Infrared rays are a type of electromagnetic wave located at the outer end of visible light red. Objects above absolute zero (-273 °C) radiate electromagnetic waves outward, and the electromagnetic waves radiated by room-temperature objects are in the infrared band. An infrared detector can detect infrared radiation and convert the infrared radiation distribution image of an object into an image visible to the human eye.

[0003] When there is a sun, a high-temperature object, or a laser within the detection range of the detector, the high-energy radiation emitted by the sun, the high-temperature object, or the laser will burn the infrared detector, causing damage to the detector or abnormal imaging.

[0004] In the prior art, the prevention of infrared detector burns mainly targets sunlight, and the main methods are as follows:

[0005] One is to use an algorithm to identify whether there are high-temperature point targets or high-temperature arcs in the imaging screen, so as to judge whether there is a sun within the detection range of the detector. When a high-temperature object such as the sun is identified, the shutter is closed to prevent the sun from burning the detector. This method requires wasting a large amount of computing resources, has a high cost, and after the shutter is closed, the detector cannot continue to image.

[0006] The other is to use a filter to filter out the short-wave infrared radiation with higher energy, reduce the energy received by the infrared detector, and thus avoid being burned by the sun. However, for an infrared detector with higher sensitivity, the remaining long-wave infrared radiation energy can still burn the detector. If the filter is used to continue filtering out the long-wave infrared radiation, the infrared detector will not receive the required infrared radiation, resulting in a sharp drop in sensitivity. Summary of the Invention

[0007] Based on this, this application provides an infrared imaging system and a thermal imager to avoid the infrared detector being burned by high-temperature objects such as the sun, and at the same time does not affect the normal use of the infrared detector.

[0008] To achieve the above object, the technical solution of the embodiment of this application is realized as follows:

[0009] On the one hand, an embodiment of the present application provides an infrared imaging system, including an infrared lens, a detector packaging structure, and a detector photosensitive chip; the detector photosensitive chip is packaged within the detector packaging structure; the infrared lens is configured to receive infrared light of a target object to be measured, and converge the infrared light onto the detector photosensitive chip after passing through the light passing area of the detector packaging structure; a phase change material layer is provided in the light passing area of the detector packaging structure, and the phase change material layer has an insulating state and a metallic state, so as to be in the insulating state to transmit light and allow the light to enter the detector packaging structure when the temperature is lower than the phase change temperature, and be in the metallic state to reflect light and prevent the light from entering the detector packaging structure when the temperature is higher than the phase change temperature.

[0010] In one embodiment, the detector packaging structure further includes a base layer and a light passing layer provided at one end of the base layer close to the infrared lens; the detector photosensitive chip is provided on the inner surface of the base layer away from the infrared lens; the phase change material layer is provided on the light passing layer.

[0011] In one embodiment, the phase change material layer is provided on the outer surface and / or the inner surface of the light passing layer.

[0012] In one embodiment, the phase change material layer is a vanadium dioxide thin film.

[0013] In one embodiment, the thickness range of the phase change material layer is 10 nm to 1 μm.

[0014] In one embodiment, the phase change temperature range of the phase change material layer is 40 °C to 120 °C.

[0015] In one embodiment, the lens material of the infrared lens includes one or more of ZnSe, ZnS, germanium-based glass, silicon-based glass, or chalcogenide glass.

[0016] In one embodiment, the light passing layer includes a main body layer and a thin film layer provided on the main body layer, the material of the main body layer includes single crystal silicon or single crystal germanium, and the thin film layer includes one of an antireflection film or an antireflection sub-wavelength microstructure.

[0017] In one embodiment, the material of the base layer includes ceramics or silicon.

[0018] On the other hand, an embodiment of the present application provides a thermal imager, including the infrared imaging system as described above.

[0019] The present application has at least the following beneficial effects: The infrared imaging system of the embodiment of the present application includes a detector packaging structure, and a phase change material layer is provided in the light-transmitting area of the detector packaging structure. When the infrared lens receives the light from a high-temperature object such as the sun and the temperature of the phase change material layer is higher than its phase change temperature, the phase change material layer can quickly transform into a metallic state, thereby reflecting the light and preventing the infrared detector from being burned. At this time, only the phase change material layer at the position where the high-temperature light is received will transform into a metallic state, while the phase change materials at other positions where the high-temperature light is not received remain in an insulating state and can transmit light, thus ensuring the normal use function of the infrared detector without burning it. When the temperature of the light received by the infrared lens does not exceed the phase change temperature of the phase change material layer, the phase change material layer is in an insulating state as a whole and maintains a normal light-transmitting function, enabling the infrared detector to be used normally. The thermal imager of the embodiment of the present application includes the above-mentioned infrared imaging system, and therefore also has the above-mentioned beneficial effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic structural diagram of the infrared imaging system of the embodiment of the present application.

[0021] Figure 2 It is a schematic structural diagram of the infrared detector (detector packaging structure and detector photosensitive chip) of the embodiment of the present application.

[0022] Figure 3 It is a schematic optical path diagram when the infrared imaging system of the embodiment of the present application is irradiated by a high-temperature object.

[0023] Figure 4 It is a schematic temperature distribution diagram of the phase change material layer when irradiated by a high-temperature object in the embodiment of the present application.

[0024] Figure 5 is Figure 4 a schematic diagram of the temperature change curve of the high-temperature blackbody region over time.

[0025] The meanings of the reference numerals in the drawings are as follows:

[0026] 1, infrared lens; 2, detector packaging structure; 21, phase change material layer; 22, light-transmitting layer; 23, base layer; 3, detector photosensitive chip; 4, high-temperature object; 5, high-temperature blackbody irradiation region; 6, high-temperature blackbody non-irradiation region. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] The technical solution of the present application will be further elaborated in detail below in conjunction with the drawings in the specification and specific embodiments.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which this application belongs. The terms used in the description of this application herein are for the purpose of describing particular embodiments only and are not intended to limit the implementation of this application. The term "and / or" as used herein includes any and all combinations of one or more of the related listed items.

[0029] In the description of this application, it should be understood that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing this application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to this application. In the description of this application, unless otherwise stated, the meaning of "a plurality of" is two or more.

[0030] In the description of this application, it should be noted that, unless otherwise clearly defined and limited, the terms "installed", "connected", "connected" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be directly connected, or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0031] Please refer to Figure 1 and Figure 2 , the infrared imaging system of the embodiment of this application includes an infrared lens 1 and an infrared detector. The infrared detector includes a detector package structure 2 and a detector photosensitive chip 3. The detector photosensitive chip 3 is encapsulated in the detector package structure 2. The infrared lens 1 is used to receive the infrared light of the object to be measured, and after passing through the light passing area of the detector package structure 2, converge the infrared light onto the detector photosensitive chip 3. A phase change material layer 21 is provided in the light passing area of the detector package structure 2. The phase change material layer 21 has an insulating state and a metallic state, so as to be in the insulating state to transmit light and allow the light to enter the detector package structure at a temperature lower than the phase change temperature, and be in the metallic state to reflect light and prevent the light from entering the detector package structure 2 at a temperature higher than the phase change temperature.

[0032] Specifically, in this embodiment, the infrared lens 1 is arranged on the outermost side, and the detector packaging structure 2 is arranged inside the infrared lens 1 for sensing infrared light entering the detector packaging structure 2 to form an image. The detector packaging structure 2 includes a base layer 23, a light-transmitting layer 22, and a phase change material layer 21. The base layer 23 is integrally in the shape of a cylindrical tube with one end open. The light-transmitting layer 22 covers the open end of the base layer 23. The light-transmitting layer 22 and the base layer 23 are combined to form a packaging structure. The detector photosensitive chip 3 is arranged inside the detector packaging structure 2 and fixed on the inner surface of the bottom plane of the base layer 23. The phase change material layer 21 is arranged on the light-transmitting layer 22. For example, it can be arranged on the outer surface (the surface close to the infrared lens 1) or the inner surface (the surface close to the detector photosensitive chip 3) of the light-transmitting layer 22. Or, a layer of phase change material layer 21 can be respectively arranged on the outer surface and the inner surface of the light-transmitting layer 22. And the phase change material layer 21 covers the outer surface and / or the inner surface of the light-transmitting layer 22. The phase change temperature range of the phase change material layer 21 is 40°C to 120°C. In this embodiment, the phase change material layer 21 is arranged on the outer surface of the light-transmitting layer 22.

[0033] Specifically, in this embodiment, the phase change material layer 21 is made of a phase change material. For example, the phase change material layer 21 can be a vanadium dioxide thin film. The thickness range of the phase change material layer 21 is 10 nm to 1 μm. The phase change material layer 21 is a uniform thin film plated on the surface of the light-transmitting layer 22. The phase change temperature of vanadium dioxide (VO2) is 68°C, and its phase change speed is on the order of sub-picoseconds (less than 10 -12 seconds), which can be ignored. This material shows an insulating state and can transmit light when the temperature is lower than the phase change temperature; it shows a metallic state and does not transmit light when the temperature is higher than the phase change temperature.

[0034] The lens material of the infrared lens 1 includes one or more of ZnSe, ZnS, germanium-based glass, silicon-based glass, or chalcogenide glass. The wider the transmission band of the infrared lens 1 is, the better. Preferably, it can transmit the visible light band. It is preferably a wide-band transmission material such as ZnSe (zinc selenide) or ZnS (zinc sulfide). One or more of conventional lens materials such as germanium-based glass, silicon-based glass, or chalcogenide glass can also be selected.

[0035] The light-transmitting layer 22 includes a body layer (not shown) and a thin film layer (not shown) arranged on the body layer. The material of the body layer includes single-crystalline silicon or single-crystalline germanium that is transparent in the infrared band. The thin film layer includes one of an anti-reflection film or an anti-reflection sub-wavelength microstructure.

[0036] The material of the base layer 23 can be selected from materials with good thermal conductivity such as ceramics or silicon.

[0037] When high-energy radiation such as the sun, high-temperature object 4, or laser irradiates an infrared detector, the phase change material integrated on the surface of the light-transmitting layer 22 and the material of the light-transmitting layer 22 rapidly increase in temperature after absorbing visible light energy and short-wave energy, reaching the phase change temperature point of the phase change material. The phase change material transforms from an insulating state to a metallic state. The phase change material in the metallic state reflects most of the energy, thus protecting the infrared detector from being burned due to high-energy radiation.

[0038] Only the phase change material in the area irradiated by high-energy radiation such as the sun, high-temperature object 4, or laser will undergo a phase change and transform into a metallic state to protect the infrared detector from being burned by high-energy radiation. The phase change material in other areas not irradiated by high-energy radiation such as the sun, high-temperature object 4, or laser will not be affected and can normally transmit light, enabling the infrared detector to form a normal image.

[0039] As Figure 3 shown, when there is a high-temperature object 4 within the detection range of the detector, the energy radiated by the high-temperature object 4, as shown by the dashed arrow, is focused onto the surface of the infrared detector through the infrared lens 1, causing the temperature of the area of the phase change material layer 21 integrated on the surface of the detector package structure 2 irradiated by the high-temperature object 4 to increase.

[0040] The temperature distribution on the surface of the detector package structure 2 is as Figure 4 shown. The temperature of the high-temperature blackbody irradiation area 5 can reach above 100 °C, exceeding the phase change temperature point of the phase change material. The phase change material in the high-temperature blackbody irradiation area 5 transforms into metallic titanium, thus reflecting most of the incident energy and protecting the detector photosensitive chip 3 within the detector package structure 2 from being burned by high temperature. The temperature of the area 6 not irradiated by the high-temperature blackbody remains near room temperature, lower than the phase change temperature point of the phase change material. The phase change material in the area 6 not irradiated by the high-temperature blackbody continues to maintain an insulating state and has a high transmittance, enabling the phase change material in the area 5 not irradiated by the high-temperature blackbody to form a normal image.

[0041] The temperature variation curve of the high-temperature blackbody irradiation area 5 is as Figure 5 shown. Within 20 ms, the temperature of the high-temperature blackbody irradiation area 5 rises to the phase change temperature point of the phase change material VO2 and undergoes a phase change. After 0.4 s, the temperature of the high-temperature blackbody irradiation area 5 basically rises to the highest temperature and enters a steady state. High temperature less than 1 second will not burn the detector photosensitive chip 3. Therefore, the infrared imaging system of the embodiment of the present application can effectively protect the infrared detector from being burned by the high-temperature object 4.

[0042] The embodiment of the present application also provides a thermal imager, which includes the above infrared imaging system.

[0043] The infrared imaging system and thermal imager provided by the embodiments of the present application can effectively prevent the infrared detector from being burned by high-temperature objects, and at the same time do not affect the normal imaging function of the infrared detector. Moreover, by setting a phase change material layer to transmit or reflect light, it can prevent the high-temperature object from radiating to the detector photosensitive chip. Its anti-burning function is realized through the physical characteristics of the detector packaging structure, without occupying a large amount of computing resources, effectively reducing the cost. While preventing burning, it does not affect the normal imaging function of the infrared detector, does not require closing the shutter, and does not reduce the sensitivity of the infrared detector.

[0044] It should be noted that in this text, the terms "including", "comprising" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or further includes elements inherent to such process, method, article or device. Without more limitations, an element defined by the statement "including one..." does not exclude the existence of another identical element in the process, method, article or device including that element.

[0045] The above is only the specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present application can easily think of changes or substitutions, which should all be covered by the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. An infrared imaging system, characterized in that, It includes an infrared lens (1), a detector packaging structure (2), and a detector photosensitive chip (3); the detector photosensitive chip (3) is packaged inside the detector packaging structure (2); the infrared lens (1) is used to receive the infrared light of the object to be measured, and after passing through the light-transmitting area of the detector packaging structure (2), converge the infrared light onto the detector photosensitive chip (3); a phase change material layer (21) is provided in the light-transmitting area of the detector packaging structure (2), and the phase change material layer (21) has an insulating state and a metallic state, so as to be in the insulating state to transmit light and allow the light to enter the detector packaging structure (2) when the temperature is lower than the phase change temperature, and be in the metallic state to reflect light and prevent the light from entering the detector packaging structure (2) when the temperature is higher than the phase change temperature.

2. The infrared imaging system according to claim 1, characterized in that, The detector packaging structure (2) further includes a base layer (23) and a light-transmitting layer (22) provided at one end of the base layer (23) close to the infrared lens (1); the detector photosensitive chip (3) is provided on the inner surface of the base layer (23) at the end far from the infrared lens (1); the phase change material layer (21) is provided on the light-transmitting layer (22).

3. The infrared imaging system according to claim 2, characterized in that, The phase change material layer (21) is provided on the outer surface and / or the inner surface of the light-transmitting layer (22).

4. The infrared imaging system according to claim 1, wherein The phase change material layer (21) is a vanadium dioxide thin film.

5. The infrared imaging system according to claim 4, characterized in that, The thickness range of the phase change material layer (21) is 10 nm to 1 μm.

6. The infrared imaging system according to claim 1, wherein, The phase change temperature range of the phase change material layer (21) is 40 °C to 120 °C.

7. The infrared imaging system according to claim 1, characterized in that, The lens material of the infrared lens (1) includes one or more of ZnSe, ZnS, germanium-based glass, silicon-based glass, or chalcogenide glass.

8. The infrared imaging system according to claim 2, characterized in that, The light-transmitting layer (22) includes a body layer and a thin film layer provided on the body layer, the material of the body layer includes single crystal silicon or single crystal germanium, and the thin film layer includes one of an antireflection film or an antireflection subwavelength microstructure.

9. The infrared imaging system according to claim 2, wherein The material of the base layer (23) includes ceramic or silicon.

10. A thermal imager, characterized in that: An infrared imaging system as claimed in any one of claims 1 to 9.

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