Microbolometer and thermal imager

Abstract

This application discloses a microbolometer, including a housing, a chip, and a light-blocking strip. The housing has a mounting cavity, and the bottom wall of the mounting cavity has a mounting protrusion with a limiting groove. The chip is disposed on the bottom wall of the mounting cavity. The light-blocking strip is embedded in the limiting groove, and the light-blocking strip is located directly above the chip and corresponds to the reference shielding area of ​​the chip. Using the above-described microbolometer, the light-blocking strip is embedded in the limiting groove. During assembly and use, the light-blocking strip can be limited by the limiting groove, thereby effectively preventing the light-blocking strip from shifting, ensuring that the light-blocking strip corresponds to the reference shielding area of ​​the chip, guaranteeing the light-blocking effect, and thus ensuring the reliability of the device. This application also discloses a thermal imager.

Description

Technical Field

[0001] This application belongs to the field of radiation detection equipment technology, specifically relating to a microbolometer and thermal imager. Background Technology

[0002] Microbolometers are core detection units widely used in uncooled infrared thermal imaging systems. Currently, mainstream microbolometers typically fix an infrared chip and getter to a designated area of ​​the housing, then install a light-blocking strip to shield the chip's reference shielding area, and finally seal the housing to form a vacuum chamber. However, existing light-blocking strips are usually bonded, which can easily shift during assembly and use. For example, during packaging, thermal stress (reflow soldering at 280~300℃) can cause a 50~100μm shift in the light-blocking strip, affecting the shielding effect. Summary of the Invention

[0003] The technical problem to be solved by this application is that existing light-blocking strips are prone to displacement during assembly and use, which affects the blocking effect. In order to solve this technical problem, a microbolometer and thermal imager that can effectively avoid the displacement of the light-blocking strip are provided.

[0004] The technical solution proposed in this application is as follows: A microbolometer, comprising: The housing has a mounting cavity, and the bottom wall of the mounting cavity is provided with a mounting protrusion, and a limiting groove is formed on the mounting protrusion; The chip is disposed on the bottom wall of the mounting cavity; A light-blocking strip is embedded in the limiting groove. The light-blocking strip is located directly above the chip and corresponds to the reference shielding area of ​​the chip.

[0005] Using the aforementioned microbolometer, the light-blocking strip is embedded in the limiting groove. During assembly and use, the light-blocking strip can be limited by the limiting groove, thereby effectively preventing the light-blocking strip from shifting, ensuring that the light-blocking strip corresponds to the reference shielding area of ​​the chip, guaranteeing the light-blocking effect, and thus ensuring the reliability of the equipment.

[0006] Furthermore, it also includes a getter, which is disposed within the mounting cavity and spaced apart from the chip.

[0007] Furthermore, the distance between the getter and the chip is not less than 3 mm.

[0008] Furthermore, the spacing d between the light-blocking strip and the chip satisfies: d ≥ 50 μm.

[0009] Furthermore, the spacing d between the light-blocking strip and the chip also satisfies: d≤80μm.

[0010] Furthermore, the mounting protrusion is arranged around the chip, and two opposing limiting grooves are formed on the mounting protrusion. The two ends of the light-blocking strip are respectively embedded in the two limiting grooves.

[0011] Furthermore, the light-blocking strip is welded to the mounting protrusion.

[0012] Furthermore, the housing also has an opening communicating with the mounting cavity; The microbolometer also includes a sealing window, which is sealed to the housing and used to close the opening.

[0013] Furthermore, the top surface of the light-blocking strip is flush with the top surface of the mounting protrusion.

[0014] A thermal imager, comprising the aforementioned microbolometer.

[0015] In summary, the microbolometer and thermal imager provided in this application have at least the following advantages: 1. The light-blocking strip is limited by the limiting groove, which can effectively prevent the light-blocking strip from shifting during assembly and use, ensure that the light-blocking strip corresponds with the reference shielding area of ​​the chip, guarantee the light-blocking effect, and thus ensure the reliability of the equipment.

[0016] 2. The spacing d between the light-blocking strip and the chip satisfies: d≥50μm. By setting a safe spacing, the risk of physical pressure damage to the microbridge pixel by the light-blocking strip is avoided.

[0017] 3. The spacing d between the light-blocking strip and the chip also meets the requirement of d≤80μm, so as to ensure chip safety while avoiding excessive thickness, which is conducive to miniaturization design.

[0018] 4. The distance between the getter and the chip should be no less than 3mm to avoid damaging the chip during the getter activation process and to improve the reliability of use. Attached Figure Description

[0019] The accompanying drawings are provided to further understand this application and form part of the specification. They are used together with the embodiments of this application to explain this application and do not constitute a limitation thereof.

[0020] Figure 1 This is a schematic diagram of the structure of a microbolometer provided in an embodiment of this application; Figure 2 for Figure 1 The diagram shown is a schematic of the microbolometer after the light-blocking strip and window are removed.

[0021] Label Explanation: 110. Housing; 111. Mounting cavity; 112. Opening; 120. Mounting protrusion; 121. Limiting groove; 130. Chip; 131. Reference shielding area; 140. Light blocking strip; 150. Window seal; 151. Solder strip; 160. Getter. Detailed Implementation

[0022] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0023] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0024] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0025] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0026] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0027] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0028] This application provides a thermal imager, which includes an infrared lens, a microbolometer, and other structures. The microbolometer provided in this application ensures that the light-blocking strip does not shift during assembly, guaranteeing its blocking effect and preventing signal drift, inaccurate temperature measurement, and uncorrectable image noise caused by shifting. This improves the imaging quality and reliability of the thermal imager.

[0029] like Figure 1 and Figure 2 As shown, in one embodiment, the microbolometer includes a housing 110, a chip 130, and a light-blocking strip 140. The housing 110 has a mounting cavity 111, and the bottom wall of the mounting cavity 111 has a mounting protrusion 120 with a limiting groove 121. The chip 130 is disposed on the bottom wall of the mounting cavity 111, specifically in the middle position of the bottom wall. The light-blocking strip 140 is disposed on the mounting protrusion 120 and embedded in the limiting groove 121. The light-blocking strip 140 is located directly above the chip 130 and corresponds to the reference shielding area 131 of the chip 130, thereby blocking light from the reference shielding area 131.

[0030] Using the microbolometer described above, the light-blocking strip 140 is embedded in the limiting groove 121. During assembly and use, the light-blocking strip 140 can be limited by the limiting groove 121, thereby effectively preventing the light-blocking strip 140 from shifting, ensuring that the light-blocking strip 140 corresponds to the reference shielding area 131 of the chip 130, ensuring the light-blocking effect, and thus ensuring the reliability of the equipment.

[0031] In one embodiment, the housing 110 also has an opening 112 communicating with the mounting cavity 111. The microbolometer also includes a sealing window 150, which is sealed to the housing 110 and used to close the opening 112. In this embodiment, the sealing window 150 is made of a material with an infrared (8~14μm band) transmittance ≥85% (coated with an anti-reflection film).

[0032] In one embodiment, the top surface of the light-blocking strip 140 is flush with the top surface of the mounting protrusion 120. Simultaneously, a solder strip 151 can be pre-installed on the side of the sealing window 150 facing the mounting cavity 111, allowing the solder strip 151 to abut against the top surfaces of the light-blocking strip 140 and the mounting protrusion 120. Thus, during assembly, the sealing window 150 can be positioned with the assistance of the mounting protrusion 120, facilitating its installation. Furthermore, since the top surface of the light-blocking strip 140 is flush with the top surface of the mounting protrusion 120, after the sealing window 150 is placed, it can be directly welded to the top surfaces of the light-blocking strip 140 and the mounting protrusion 120 using the solder strip 151, ensuring the sealing performance of the sealing window 150.

[0033] In one embodiment, the mounting protrusion 120 is disposed around the chip 130, specifically... Figure 1 In the illustrated embodiment, the bottom wall of the mounting cavity 111 and the chip 130 are both rectangular, and the mounting protrusion 120 is provided along the edge of the bottom wall of the mounting cavity 111. At the same time, two opposing limiting grooves 121 are formed on the mounting protrusion 120, and the two ends of the light-blocking strip 140 are respectively embedded in the two limiting grooves 121.

[0034] In practical applications, the light-blocking strip 140 can be made of Kovar alloy or silicon, with its surface treated by alkaline oxidation to form a 2-5 μm thick iron oxide film, or coated with Al metal on one side. The light-blocking strip 140 has a light-blocking rate ≥98%. Furthermore, it is understood that the dimensions of the light-blocking strip 140 and the limiting groove 121 are matched to ensure that the limiting groove 121 can limit the light-blocking strip 140.

[0035] In one embodiment, the light-blocking strip 140 is welded to the mounting protrusion 120. This effectively avoids the risk of adhesive contamination of the chip 130 compared to bonding the light-blocking strip 140 to the mounting protrusion 120 with adhesive. Of course, even if adhesive is used, with the limiting groove 121 provided, adhesive can be applied directly within the limiting groove 121, filling the gap between the light-blocking strip 140 and the limiting groove 121, thereby reducing the possibility of adhesive overflowing into the chip 130 and lowering the risk of chip 130 contamination.

[0036] In one embodiment, the spacing d between the light-blocking strip 140 and the chip 130 satisfies: d ≥ 50 μm. By setting a safe spacing, the risk of physical pressure damage to the microbridge pixels by the light-blocking strip 140 is avoided. Furthermore, the spacing d between the light-blocking strip 140 and the chip 130 also satisfies: d ≤ 80 μm, so as to ensure the safety of the chip 130 while avoiding excessive thickness.

[0037] In one embodiment, the microbolometer further includes a getter 160. The getter 160 is disposed within the mounting cavity 111 and spaced apart from the chip 130. It is determined that the housing 110 is provided with a conductive structure connected to the getter 160, and the getter 160 can be activated through the conductive structure after assembly.

[0038] In practical applications, the distance between the getter 160 and the chip 130 is no less than 3 mm. It should be explained that the getter 160 generates high temperatures during activation, and the activation time is relatively long. If the getter 160 and the chip 130 are too close, for example, 1 mm or 2 mm, the high temperature generated during activation will have a destructive impact on the microbridge pixel structure and readout circuit in the chip 130. Furthermore, the temperature that the thermistor layer in the chip 130 can withstand is typically no more than 250°C, and the activation time cannot be too long, as this will lead to lattice reconstruction in the thermistor layer and disruption of resistance uniformity. Specifically, the getter 160 is disposed on the bottom wall of the mounting cavity 111, located between the mounting protrusion 120 and the chip 130.

[0039] In summary, the microbolometer and thermal imager provided in this application have at least the following advantages: 1. The light-blocking strip 140 is limited by the limiting groove 121. During assembly and use, the light-blocking strip 140 can be effectively prevented from shifting, ensuring that the light-blocking strip 140 corresponds to the reference shielding area 131 of the chip 130, thus ensuring the light-blocking effect and the reliability of the equipment.

[0040] 2. The spacing d between the light-blocking strip 140 and the chip 130 satisfies: d≥50μm. By setting a safe spacing, the risk of physical pressure damage to the microbridge pixel by the light-blocking strip 140 is avoided.

[0041] 3. The spacing d between the light-blocking strip 140 and the chip 130 also satisfies: d≤80μm, so as to ensure the safety of the chip 130 while avoiding excessive thickness, which is conducive to miniaturization design.

[0042] 4. The gap between the getter 160 and the chip 130 shall not be less than 3mm, so as to avoid damage to the chip 130 during the activation process of the getter 160 and improve the reliability of use.

[0043] Although embodiments of this application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A microbolometer, characterized in that, include: The housing has a mounting cavity, and the bottom wall of the mounting cavity is provided with a mounting protrusion, and a limiting groove is formed on the mounting protrusion; The chip is disposed on the bottom wall of the mounting cavity; A light-blocking strip is embedded in the limiting groove. The light-blocking strip is located directly above the chip and corresponds to the reference shielding area of ​​the chip.

2. The microbolometer according to claim 1, characterized in that, It also includes a getter, which is disposed within the mounting cavity and spaced apart from the chip.

3. The microbolometer according to claim 2, characterized in that, The distance between the getter and the chip is not less than 3 mm.

4. The microbolometer according to claim 1, characterized in that, The distance d between the light-blocking strip and the chip satisfies: d ≥ 50 μm.

5. The microbolometer according to claim 4, characterized in that, The distance d between the light-blocking strip and the chip also satisfies: d≤80μm.

6. The microbolometer according to claim 1, characterized in that, The mounting protrusion is arranged around the chip, and two opposing limiting grooves are formed on the mounting protrusion. The two ends of the light-blocking strip are respectively embedded in the two limiting grooves.

7. The microbolometer according to claim 1, characterized in that, The light-blocking strip is welded to the mounting protrusion.

8. The microbolometer according to claim 1, characterized in that, The housing also has an opening that communicates with the mounting cavity; The microbolometer also includes a sealing window, which is sealed to the housing and used to close the opening.

9. The microbolometer according to claim 8, characterized in that, The top surface of the light-blocking strip is flush with the top surface of the mounting protrusion.

10. A thermal imager, characterized in that, Includes the microbolometer as described in any one of claims 1-9.

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