Infrared sensor and packaging method thereof
By designing a compartmentalized vacuum chamber within the infrared sensor and using external laser heating of the getter, the problem of high-temperature damage to the chip during getter activation is solved, enabling a flexible and efficient packaging process.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-25
- Publication Date
- 2026-03-27
AI Technical Summary
Existing thermal infrared sensors require high temperatures during getter activation, which may damage the infrared sensing chip and filter. Furthermore, the packaging process requires specialized equipment, lacking flexibility.
Design an infrared sensor comprising an infrared sensing chip, a getter, and an optical window in a vacuum chamber, which is divided into an infrared sensing chamber and a getter activation chamber. The getter is heated from the outside using a laser lens, and the chip is protected by a heat insulation plate and a buffer chamber to avoid high-temperature damage. The activation process is completed outside the vacuum reflow oven.
This achieves efficient activation of the getter, avoids damage to the chip from high temperatures, and improves the flexibility and efficiency of the packaging process.
Smart Images
Figure CN121740248A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of infrared sensor technology, and in particular relates to infrared sensors and their packaging methods. Background Technology
[0002] Infrared sensors have applications in various aspects of life, including medicine, science, commerce, and the military, such as body temperature detection, infrared spectrometers, remote controls, anti-theft devices, and laser detection. Infrared sensors can be mainly divided into two categories: thermal and photonic. Thermal infrared sensors are generally more convenient to use and have wider applications. Current thermal infrared sensors use an infrared sensing chip to detect infrared light and generate a sensor image, and a vacuum chamber to improve the sensitivity of the infrared sensing chip. A getter is placed inside the vacuum chamber to maintain the vacuum level and extend the lifespan of the infrared sensor.
[0003] As described above, a traditional thermal infrared sensor includes at least an infrared sensing chip, a vacuum chamber, an infrared filter, a getter, and a lens. The infrared sensing chip, housed within the vacuum chamber, senses infrared light to generate a sensored image. The infrared filter filters out light other than infrared. To prevent infrared light reflection and image quality degradation, an anti-reflective layer can be coated or deposited on the infrared filter. The vacuum chamber enhances the sensitivity of the infrared sensing chip. The getter, placed within the vacuum chamber, maintains the vacuum level for extended periods, improving the sensor's lifespan. The lens focuses infrared light onto the infrared sensing chip to produce a clear image.
[0004] However, the existing technology still has the following technical problems: In infrared sensors, the getter needs to be activated. Since the activation temperature of the getter exceeds 300°C, in order to avoid damage to the anti-reflective layer of the infrared sensing chip and infrared filter by high temperature, the infrared sensor requires a special machine to perform the getter activation process. To meet the activator temperature requirements and simplify the packaging scheme, a dedicated shell and an effective packaging method also need to be designed. Summary of the Invention
[0005] The purpose of this invention is to provide an infrared sensor to solve the technical problems mentioned in the background art.
[0006] The technical solution adopted by the present invention to solve its technical problem is as follows: An infrared sensor is provided, comprising a vacuum chamber with an internal infrared sensing chip, a getter, and an optical window. The vacuum chamber is formed by a substrate and an end cap. The vacuum chamber is divided into several sub-chambers by a main partition. Each sub-chamber includes an infrared sensing chamber and a getter activation chamber. The infrared sensing chip is fixed on the substrate of the infrared sensing chamber, and the optical window is fixed on the end cap of the infrared sensing chamber. The getter is located in the getter activation chamber to maintain the vacuum level of the vacuum chamber. A through hole facing the getter is opened on the substrate or end cap of the getter activation chamber, and a laser lens is embedded in the through hole. A main connecting hole for connecting the getter activation chamber and the infrared sensing chamber is opened on the main partition.
[0007] Preferably, a buffer chamber is provided between the infrared sensing chamber and the gas absorption activation chamber. The buffer chamber is separated from the vacuum chamber and the gas absorption activation chamber by the main partition. The main partition has a main communication hole for connecting the gas absorption activation chamber and the infrared sensing chamber to the buffer chamber respectively.
[0008] Preferably, the buffer chamber is provided with a maze formed by secondary partitions.
[0009] Preferably, the main partition between the vacuum chamber and the gas-absorbing activation chamber is a heat-insulating plate.
[0010] Preferably, the substrate is provided with a heat-conducting block, and the getter is adhered to the heat-conducting block of the substrate by an adhesive.
[0011] Preferably, the substrate is a ceramic substrate or a metal substrate.
[0012] Preferably, the substrate is a leadless substrate.
[0013] Preferably, the optical window is provided with an anti-reflective layer, and an infrared filter is provided on the inner side of the optical window.
[0014] Preferably, the end cap is a metal cap and is fixed to the substrate by welding.
[0015] To address the above technical problems, the present invention also provides a packaging method for an infrared sensor, used to package the infrared sensor as described above, comprising the following steps: S1. A base and an end cap are installed inside the vacuum chamber of the vacuum reflow oven. The base is divided into several compartments by a main partition. The compartments include an infrared sensing compartment and a gas-absorbing activation compartment. A solder ring is provided on the top surface of the base. An infrared sensing chip is provided in the infrared sensing compartment. A gas-absorbing activation compartment is provided with a getter. S2. The base and end cap are welded together in a vacuum reflow oven to bring the vacuum chamber of the infrared sensor to a preliminary high vacuum state. S3. A laser heater is installed in or outside the vacuum reflow oven, and a heat dissipation device is installed outside the adhesion position of the getter. The getter is heated to the activation temperature of the getter by laser irradiation through a laser lens located on the substrate or end cap facing the getter.
[0016] The beneficial effects are as follows: The infrared sensor provided by this invention can easily and accurately meet the activation temperature requirements of the activator by focusing the laser to heat it. The separately arranged suction activation chamber and heat insulation plate can avoid high-temperature damage to the infrared sensing chip during activation. Since the activator is heated and activated from the outside without contact by laser, the activation operation can be completed without being limited to a vacuum reflow oven, thus improving the flexibility of the infrared sensor packaging operation. Attached Figure Description
[0017] Figure 1 A stereoscopic view of an infrared sensor; Figure 2 A 3D view of the infrared sensor without the end cap installed; Figure 3 for Figure 2 Top view of the middle substrate; Figure 4 for Figure 2 Bottom view of the middle substrate; Figure 5 for Figure 2 A structural diagram of one embodiment of the secondary partition in the buffer chamber; Figure 6 This is a flowchart of an infrared sensor packaging process.
[0018] Among them, 1-substrate; 101-main partition; 102-main connecting hole; 103-secondary partition; 104-horizontal partition; 105-vertical partition; 106-secondary connecting hole; 2-solder ring; 3-end cap; 4-infrared sensing chamber; 401-infrared sensing chip; 402-optical viewing window; 5-getter activation chamber; 501-getter; 502-laser lens; 6-buffer chamber; 7-heat conduction block.
[0019] The same markings in each diagram represent the same component. Detailed Implementation
[0020] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.
[0021] like Figure 1 As shown, this invention provides an infrared sensor, including a vacuum chamber containing an infrared sensing chip 401, a getter 501, and an optical window 402. The infrared sensing chip 401, getter 501, and optical window 402 are all conventional structures for infrared sensors. Typically, an infrared filter is provided inside the optical window 402 to achieve the basic functions of the infrared sensor. However, those skilled in the art can arbitrarily arrange the shape, position, and form of the infrared sensing chip 401, getter 501, and optical window 402, such as directly using an infrared lens or adding an anti-reflection layer. The infrared sensing scheme is not part of the inventive point of this invention and will not be elaborated upon here.
[0022] Specifically, such as Figure 2 , 3 As shown, in an embodiment of the present invention, the vacuum chamber is formed by sealing a substrate 1 and an end cap 3. The vacuum chamber is divided into several sub-chambers by a main partition 101. Each sub-chamber includes at least an infrared sensing chamber 4 and a getter activation chamber 5. The infrared sensing chip 401 is fixed on the substrate 1 of the infrared sensing chamber 4. The optical viewing window 402 is fixed on the end cap 3 of the infrared sensing chamber 4. The getter 501 is located in the getter activation chamber 5 to maintain the vacuum level of the vacuum chamber.
[0023] See you again Figure 1 The substrate 1 or end cap 3 of the gas-absorbing activation chamber 5 has a through hole facing the getter 501, and a laser lens 502 is embedded in the through hole. The main partition 101 has a main connecting hole 102 for connecting the gas-absorbing activation chamber 5 and the infrared sensing chamber 4.
[0024] Figure 1 The through-hole and laser lens 502 described herein are circular in shape. Figure 2 The getter 501 is rectangular in shape. The two figures are not related. The shape and size in the figures are only for illustration. Those skilled in the art are able to design and arrange a sufficient amount of getter 501 according to the size of the infrared sensor and the volume of its internal vacuum chamber, and design the corresponding shape and size according to the dosage. Accordingly, the shape and size of the through hole and the embedded laser lens 502 should actually be larger than the shape and size of the getter 501, so that the getter can be fully heated and activated by the laser heater.
[0025] Furthermore, when the getter 501 is not large, the laser lens 502 can be a convex lens. A convex lens has the function of converging light rays. When the laser beam passes through the convex lens, the light rays are focused onto the focal point on the surface of the getter 501, thereby greatly increasing the energy density at the focal point. In scenarios where the getter 501 is heated, the laser energy needs to be concentrated on the surface of the getter 501 to achieve a rapid heating effect, quickly and simultaneously activating all of the getter 501.
[0026] In this embodiment, the main partition 101 between the vacuum chamber and the getter activation chamber 5 is a heat insulation plate, such as made of ceramic. Ceramic plates have strong high-temperature resistance, low thermal conductivity, and good insulation. At the same time, the thickness of the heat insulation plate can be thicker than the outer wall of the vacuum chamber to prevent the high temperature during activation of the getter 501 from being directly conducted into the infrared sensing chamber 4, thus avoiding high-temperature damage to the infrared sensing chip 401.
[0027] In this embodiment, a buffer chamber 6 is provided between the infrared sensing chamber 4 and the air intake activation chamber 5. The buffer chamber 6 is used to extend the distance between the infrared sensing chamber 4 and the air intake activation chamber 5, thereby improving the heat dissipation effect. The vacuum chamber and the air intake activation chamber 5 are separated by the main partition 101, and the main partition 101 has a main connecting hole 102 for connecting the air intake activation chamber 5 and the infrared sensing chamber 4 to the buffer chamber 6 respectively.
[0028] like Figure 4 As shown, the substrate 1 is provided with a heat-conducting block 7 with a high thermal conductivity, such as a metal material. Specifically, the heat-conducting block 7 is provided on the substrates of the intake activation chamber 5 and the buffer chamber 6, which helps to dissipate heat through an external heat dissipation device. The getter 501 is adhered to the heat-conducting block 7 on the substrate 1 by an adhesive to prevent it from shifting away from the intake activation chamber 5 during transportation, and to quickly dissipate excess heat during the activation process.
[0029] In a typical design, the getter 501 is disposed on the substrate 1. The main communication hole 102 connecting the getter activation chamber 5 and the buffer chamber 6 is located at the upper end of the main partition 101 between them, while the main communication hole 102 between the buffer chamber 6 and the infrared sensing chamber 4 is located at the lower end of the main partition. The bottom and / or sides of the buffer chamber 6 are also provided with heat-conducting blocks 7 with high thermal conductivity. If the material is metal, a heat dissipation device can be arranged on the outside of the substrate 1 to assist in heat dissipation, preventing the high temperature of the getter 501 during activation from being conducted into the infrared sensing chamber 4 and causing high-temperature damage to the infrared sensing chip 401.
[0030] The buffer chamber 6 is equipped with a labyrinth formed by secondary partitions 103, further extending the distance between the infrared sensing chamber 4 and the air intake activation chamber 5. Figure 5In one specific embodiment, the secondary partition 103 includes a horizontal partition 104 and a vertical partition 105 located at the lower center of the horizontal partition 104, which can divide the buffer chamber 6 into an upper channel and two lower channels. Each channel is connected by a secondary connecting hole 106. The cross-sectional dimensions of each connecting hole and channel should be as equal as possible. In this embodiment, the heat dissipation direction is shown by the arrow in the figure. In other embodiments, the arrangement of the secondary partition 103 can be changed according to the position of the main connecting hole 102 between each chamber, such as by swapping the positions of the horizontal partition 104 and the vertical partition 105.
[0031] Since the vacuum chamber is in a near-vacuum state, thermal convection is negligible. The heat generated by laser heating of the getter 501 is partially blocked by the main partition 101 (which acts as a heat shield) through thermal conduction, and most of it is dissipated to the external heat dissipation device via the heat-conducting block 7. The portion dissipated through thermal radiation within the buffer chamber 6 has a long and winding path, and most of it is absorbed by the main partition 101, secondary partition 103, and substrate 1 before being dissipated to the external heat dissipation device via the heat-conducting block 7. Ultimately, this invention satisfies the purpose of ensuring the vacuum level within the vacuum chamber by activating the getter 501 at high temperature, while also ensuring that the residual heat reaching the infrared sensing chamber 4 is insufficient to damage the infrared sensing chip 401.
[0032] The substrate 1 may be, but is not limited to, a ceramic substrate 1 or a metal substrate 1, and the form of the substrate 1 is not limited to a leadless substrate 1.
[0033] In this embodiment, a solder ring 2 is arranged on the substrate 1, and the end cap 3 is a metal cap, which is fixed to the substrate 1 by welding. However, the connection method of the present invention is not limited to heat curing welding performed in a vacuum reflow oven.
[0034] like Figure 6 As shown, in order to encapsulate any of the infrared sensors described above, the encapsulation method includes the following steps: S1. A base and an end cap 3 are installed inside the vacuum chamber of the vacuum reflow oven. The base is divided into several compartments by a main partition 101. The compartments include an infrared sensing chamber 4 and a gas-absorbing activation chamber 5. A solder ring 2 is provided on the top surface of the base. An infrared sensing chip 401 is provided in the infrared sensing chamber 4. A gas-absorbing activation chamber 5 is provided with a gas-absorbing agent 501. S2. The base and end cap 3 are welded together in a vacuum reflow oven to bring the vacuum chamber of the infrared sensor to a preliminary high vacuum state. S3. A laser heater is installed in or outside the vacuum reflow oven, and a heat dissipation device is installed outside the adhesion position of the getter 501. The getter 501 is heated to the activation temperature of the getter 501 by laser irradiation through a laser lens 502 located on the substrate 1 or end cap 3 facing the getter 501, so as to activate the getter 501.
[0035] The welding process in S2 is a conventional welding process, which will not be described in detail here. The laser heating in S3 can use a low-power semiconductor continuous laser and is equipped with an infrared temperature probe to monitor the temperature of the activator in the getter activation chamber 5 in real time. It can also realize over-temperature alarm and delayed shutdown, and keep the getter 501 at the activation temperature for at least 10 minutes to achieve full activation.
[0036] In S3, besides the adhesion site of the getter 501 (i.e., the heat-conducting block 7 of the getter activation chamber 5), when the infrared sensor also has a buffer chamber 6, a heat dissipation device is also provided outside the heat-conducting block 7 of the buffer chamber 6. The heat dissipation device here is a water-cooling device or an air-cooling device, which quickly dissipates excess heat in the getter activation chamber 5 and the buffer chamber 6 through heat conduction, further preventing high temperature damage to the infrared sensing chip 401 during activation.
Claims
1. An infrared sensor comprising a vacuum chamber having an infrared sensing chip, a getter, and an optical window disposed therein, wherein, The vacuum chamber is closed by a base plate and an end cover, and is divided into several sub-chambers by a main partition plate, including an infrared sensing chamber and a getter activation chamber, The infrared sensing chip is fixed on the base plate of the infrared sensing chamber, and the optical window is fixed on the end cover of the infrared sensing chamber, The getter is located in the getter activation chamber for maintaining the vacuum degree of the vacuum chamber, a through hole is opened on the base plate or the end cover of the getter activation chamber, a laser lens is embedded in the through hole, and a main communication hole is opened on the main partition plate for connecting the getter activation chamber and the infrared sensing chamber.
2. The infrared sensor of claim 1, wherein, A buffer chamber is arranged between the infrared sensing chamber and the getter activation chamber, and the buffer chamber is separated from the vacuum chamber and the getter activation chamber by the main partition plate, and a main communication hole is opened on the main partition plate for connecting the getter activation chamber and the infrared sensing chamber with the buffer chamber.
3. An infrared sensor according to claim 2, wherein A labyrinth is arranged in the buffer chamber and is separated by a secondary partition plate.
4. The infrared sensor of claim 1, wherein, The main partition plate between the vacuum chamber and the getter activation chamber is a heat insulation plate.
5. The infrared sensor of claim 1, wherein, A heat conduction block is arranged on the base plate, and the getter is adhered to the heat conduction block of the base plate by an adhesive.
6. The infrared sensor of claim 1, wherein, The base plate is a ceramic base plate or a metal base plate.
7. The infrared sensor of claim 1, wherein, The base plate is a leadless base plate.
8. The infrared sensor of claim 1, wherein, An anti-reflection layer is arranged on the optical window, and an infrared filter is arranged on the inner side of the optical window.
9. The infrared sensor of claim 1, wherein, The end cover is a metal cover and is fixed to the base plate by welding.
10. A method of packaging an infrared sensor, comprising: A packaging method for packaging an infrared sensor according to any one of claims 1-9, comprising the following steps: S1, a base plate and an end cover are placed in the vacuum cavity of a vacuum reflow furnace, the base plate is divided into several sub-chambers by a main partition plate, the sub-chambers include an infrared sensing chamber and a getter activation chamber, a solder ring is arranged on the top surface of the base plate, an infrared sensing chip is arranged in the infrared sensing chamber, and a getter is arranged in the getter activation chamber; S2, the base plate and the end cover are welded together in the vacuum reflow furnace, so that the vacuum chamber of the infrared sensor is in a preliminary high vacuum state; S3, a laser heater is arranged in the vacuum reflow furnace or outside, a heat dissipation device is arranged outside the adhesion position of the getter, the getter is irradiated by a laser through a laser lens arranged on the base plate or the end cover and facing the getter, and the getter is heated to an activation temperature to activate the getter.