An infrared focal plane detector and method of manufacture

Abstract

The application discloses an infrared focal plane detector, comprising an infrared focal plane array and a microlens array, wherein the infrared focal plane array comprises an infrared detector chip, and the array surface of the microlens array is connected with the infrared detector chip. The application integrates the microlens array on the infrared focal plane array, thereby improving the light energy utilization rate of the infrared focal plane detector and further improving the sensitivity of the infrared focal plane detector. Meanwhile, the application also provides a manufacturing method of the infrared focal plane detector. First, a structure mold is processed, the structure mold has a concave surface matched with the shape of the microlens array, then a glass blank is molded to obtain the microlens array, a substrate is arranged at the bottom of the microlens array, then the array surface of the microlens array is adhered to the infrared detector chip, and the substrate is removed to obtain the infrared focal plane detector.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of infrared detector and its peripheral facilities, in particular to an infrared focal plane detector and a manufacturing method. BACKGROUND

[0002] The infrared focal plane of the detector itself is composed of a large number of pixels, which convert the received optical signals into electrical signals through photoelectric effect. In order to send these electrical signals, a shift gate and a shift register need to be set between the pixels, so that the pixels cannot fully occupy the surface area of the infrared focal plane array, and there will be a gap with an area ratio of about 1 / 3. The utilization rate of infrared light energy of the pixel is only 30% to 60%, and the reduction of the effective receiving area directly leads to the reduction of the photosensitivity of the infrared focal plane array.

[0003] The infrared microlens array refers to an array combination of micrometer-scale infrared lenses, and its energy concentration effect can regulate and utilize the physical properties of infrared light waves. The manufacturing of the infrared microlens array is to obtain a lens array unit with a feature size in the micron level on the surface of an infrared material by using a certain process method. At present, the processing technologies of the microlens array mainly include thermal reflow technology, micro-droplet jetting technology, and injection molding technology. These three methods are mainly for microlens arrays of resin materials, and there are certain limitations in the shape, consistency and size range of the units. Taking the thermal reflow technology as an example, its technical principle is as shown in Figure 1 The array structure is heated to the glass transition temperature of the photoresist, so that the array columnar structure forms a microlens array under the action of surface tension, and finally it is integrated with the infrared focal plane detector. However, the infrared microlens array manufactured by the existing technology has certain problems, which makes it not suitable for integration in the infrared detector or the effect is poor after integration.

[0004] Firstly, the existing technology has poor controllability for the manufactured infrared microlens array. It is difficult to control the lens curvature and aperture size of the infrared microlens array manufactured by material tension, and the shape precision is poor and it is impossible to manufacture a rectangular aperture microlens array. At the same time, due to the spontaneous formation of liquid droplets, the consistency of the manufactured microlens array is poor and the precision is difficult to guarantee. Affected by the size effect, the size range of the lens unit that can be manufactured by the existing technology is limited, and the lens size is large, which cannot be used for the integration of the infrared focal plane detector. Secondly, the existing technology all uses resin materials, which have low infrared transmittance, narrow transmittance range, and low chemical stability and physicochemical properties. In addition, the traditional integration method of the infrared detector is to integrate the microlens array structure upward, as shown in Figure 2Based on the refraction principle of light, the integrated infrared light should converge to the image element after passing through the upper surface of the lens, that is, the thickness of the infrared microlens array should be consistent with the focal length of the microlens array, which requires that the thickness of the manufactured infrared microlens array be thinned to less than 100 microns, increase the process, and some materials cannot reach such thickness.

[0005] Therefore, in the prior art, the precision of the microlens array in the prior art is poor, which affects the sensitivity of the detector, and this has become a problem to be solved by those skilled in the art. SUMMARY

[0006] The purpose of the present application is to provide an infrared focal plane detector and a manufacturing method to solve the problems existing in the prior art and improve the manufacturing precision of the microlens array and the sensitivity of the infrared focal plane detector.

[0007] To achieve the above purpose, the present application provides the following scheme: the present application provides an infrared focal plane detector, comprising:

[0008] An infrared focal plane array, the infrared focal plane array comprising an infrared detector chip;

[0009] A microlens array, the array surface of the microlens array being connected with the infrared detector chip.

[0010] Preferably, the microlens array is connected with the infrared detector chip by adhesion.

[0011] Preferably, the microlens array is connected with the infrared detector chip by adhesion using optical glue.

[0012] The present application also provides a manufacturing method of an infrared focal plane detector, comprising the following steps:

[0013] Step one, a structure mold with a concave surface is processed, the concave surface being matched with the shape of the array surface of the microlens array;

[0014] Step two, the structure mold is placed at the bottom of a glass blank, the concave surface facing the glass blank, the structure mold and the glass blank are heated, the structure mold is subjected to pressure, and the glass blank is subjected to mold pressing to obtain the microlens array;

[0015] Step three, a substrate is connected at the bottom of the microlens array, the substrate being located at the side away from the array surface of the microlens array;

[0016] Step four, the array surface of the microlens array is adhered with an infrared detector chip;

[0017] Step five, the substrate is removed to obtain the infrared focal plane detector.

[0018] Preferably, in step one, the concave surface is a spherical surface or an aspherical spherical crown.

[0019] Preferably, in step one, the concave surface is machined.

[0020] Preferably, in step two, the glass blank is made of a chalcogenide glass material.

[0021] Preferably, in step three, the substrate is fixed to the bottom of the microlens array by adhesion.

[0022] Preferably, in step four, optical adhesive is coated on the infrared detector chip, and the microlens array is adhered by the optical adhesive.

[0023] Preferably, in step four, the optical adhesive is spin-coated on the infrared detector chip.

[0024] The infrared focal plane detector of the present application includes an infrared focal plane array and a microlens array, wherein the infrared focal plane array includes an infrared detector chip, and the array surface of the microlens array is connected to the infrared detector chip. The present application integrates the microlens array on the infrared focal plane array, thereby improving the light energy utilization rate of the infrared focal plane detector and further improving the sensitivity of the infrared focal plane detector.

[0025] Meanwhile, the present application also provides a method for manufacturing an infrared focal plane detector. First, a structure mold is machined, which has a concave surface matching the shape of the microlens array. Then, a glass blank is molded to obtain the microlens array, greatly improving the precision and consistency of the machined microlens array. After the microlens array is obtained by using the structure mold, a substrate is arranged at the bottom of the microlens array, and then the microlens array and the substrate are connected to the infrared focal plane array. The substrate is used to adhere the microlens array, which is convenient to operate. The array surface of the microlens array is adhered to the infrared detector chip, avoiding the influence of the microlens array on the detector. After removing the substrate, the infrared focal plane detector is obtained. BRIEF DESCRIPTION OF DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0027] Figure 1 A schematic diagram of the principle of the existing technology of thermal reflow technology;

[0028] Figure 2The schematic diagram of the integration of the infrared focal plane array in the prior art is shown in the figure;

[0029] Figure 3 The schematic diagram of step one of the manufacturing method of the infrared focal plane detector of the present application is shown in the figure;

[0030] Figure 4 The structural schematic diagram of the processing device of the microlens array of the present application is shown in the figure;

[0031] Figure 5 The working schematic diagram of the processing device of the microlens array of the present application is shown in the figure;

[0032] Figure 6 The schematic diagram of step three of the manufacturing method of the infrared focal plane detector of the present application is shown in the figure;

[0033] Figure 7 The schematic diagram of the spin-coating of the optical glue on the infrared detector chip in the manufacturing method of the infrared focal plane detector of the present application is shown in the figure;

[0034] Figure 8 The schematic diagram of step four of the manufacturing method of the infrared focal plane detector of the present application is shown in the figure;

[0035] Figure 9 The schematic diagram of step five of the manufacturing method of the infrared focal plane detector of the present application is shown in the figure.

[0036] In the figure, 1 is a structure mold, 2 is a concave surface, 3 is a glass blank, 4 is a plane mold, 5 is a first sleeve, 6 is a second sleeve, 7 is a substrate, 8 is an infrared detector chip, 9 is optical glue, 10 is a microlens array, 11 is a pixel, and 12 is a circuit board. DETAILED DESCRIPTION

[0037] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0038] The purpose of the present application is to provide an infrared focal plane detector and a manufacturing method to solve the problems in the prior art and improve the manufacturing precision of the microlens array and the sensitivity of the infrared focal plane detector.

[0039] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the present application will be further described in detail below with reference to the drawings and specific embodiments.

[0040] Please refer to Figures 3-9 , wherein, Figure 3The schematic diagram of step one of the infrared focal plane detector manufacturing method of the present application, Figure 4 The structural schematic diagram of the processing device of the microlens array of the present application, Figure 5 The working schematic diagram of the processing device of the microlens array of the present application, Figure 6 The schematic diagram of step three of the infrared focal plane detector manufacturing method of the present application, Figure 7 The schematic diagram of spin coating optical glue on the infrared detector chip in the infrared focal plane detector manufacturing method of the present application, Figure 8 The schematic diagram of step four of the infrared focal plane detector manufacturing method of the present application, Figure 9 The schematic diagram of step five of the infrared focal plane detector manufacturing method of the present application.

[0041] The present application provides an infrared focal plane detector, comprising an infrared focal plane array and a microlens array 10, wherein the infrared focal plane array comprises an infrared detector chip 8, and the array surface of the microlens array 10 is connected with the infrared detector chip 8. The present application integrates the microlens array 10 on the infrared focal plane array, thereby improving the light energy utilization rate of the infrared focal plane detector, and further improving the sensitivity of the infrared focal plane detector.

[0042] It should also be explained here that the infrared focal plane array further comprises a pixel 11 and a circuit board 12, as shown in Figure 7 The array surface of the microlens array 10 is connected with the infrared detector chip 8, and the lenses of the microlens array 10 are fixedly connected with the pixel 11.

[0043] Specifically, the microlens array 10 is connected with the infrared detector chip 8 by adhesion. In order to avoid the influence of glue connection on the performance of the detector, optical glue 9 can be selected to realize the adhesion connection of the microlens array 10 and the infrared detector chip 8 in actual application.

[0044] Meanwhile, the present application also provides an infrared focal plane detector manufacturing method, comprising the following steps:

[0045] Step one, a structure mold 1 with a concave surface 2 is processed, and the concave surface 2 is matched with the shape of the array surface of the microlens array 10;

[0046] Step two, the structure mold 1 is placed at the bottom of a glass blank 3, the concave surface 2 faces the glass blank 3, the structure mold 1 and the glass blank 3 are heated, the structure mold 1 is pressed, and the glass blank 3 is formed by molding to obtain the microlens array 10;

[0047] Step three, a substrate 7 is connected at the bottom of the microlens array 10, and the substrate 7 is located at the side away from the array surface of the microlens array 10;

[0048] Step four, bonding the array surface of the microlens array 10 with the infrared detector chip 8;

[0049] Step five, removing the substrate 7 to obtain the infrared focal plane detector.

[0050] After the microlens array 10 is prepared by using the structure mold 1, the substrate 7 is arranged at the bottom of the microlens array 10, and then the microlens array 10 and the substrate 7 are connected with the infrared focal plane array. The substrate 7 is used to bond the microlens array 10, which is convenient to operate. The array surface of the microlens array 10 is bonded on the infrared detector chip 8, which avoids the influence of the microlens array 10 on the detector. After the substrate 7 is removed, the infrared focal plane detector is obtained.

[0051] It should be emphasized that the concave surface 2 is a spherical surface or a non-spherical spherical crown. The appropriate concave surface 2 can be selected according to the type of detector, and then the appropriate type of microlens array 10 is obtained.

[0052] More specifically, the concave surface 2 is machined by a mechanical processing method. The structure mold 1 is manufactured by a mechanical processing method, which has high controllability. Then, the glass blank 3 is molded to obtain the microlens array 10, which greatly improves the precision and consistency of the machined microlens array 10.

[0053] In addition, in step two, the glass blank 3 is made of a chalcogenide glass material. The chalcogenide glass has unique advantages as an infrared lens material, such as high infrared transmittance and wide transmittance range, which is beneficial to improve the performance of the infrared focal plane detector.

[0054] In this specific embodiment, in step three, the substrate 7 is connected to the bottom of the microlens array 10 by bonding, which facilitates the subsequent operation of removing the substrate 7.

[0055] In addition, in step three, the substrate 7 is fixed to the bottom of the microlens array 10 by bonding. The substrate 7 is located on the side away from the array surface of the microlens array 10, which is convenient to operate and provides convenience for the subsequent removal of the substrate 7.

[0056] Further, in step four, the optical glue 9 is spin-coated on the infrared detector chip 8, and then the microlens array 10 is aligned with the pixel 11 of the infrared detector chip 8 and bonded.

[0057] It should be further noted that when the microlens array 10 is processed, the processing device includes the structure mold 1. The structure mold 1 has the concave surface 2, which matches the shape of the microlens array 10. The structure mold 1 is manufactured by a mechanical processing method, which can process the microlens array 10 with high precision and high consistency.

[0058] Meanwhile, the processing device of the microlens array 10 further comprises a flat mold 4, which is arranged on the top of the structure mold 1, the concave surface 2 is arranged towards the flat mold 4, and the structure mold 1 and the flat mold 4 can accommodate the glass blank 3 to be processed. In the process of producing the microlens array 10, the flat mold 4 can be heated to heat the glass blank 3, thereby improving the heating uniformity of the glass blank 3.

[0059] In actual operation, the processing device of the microlens array 10 further comprises a first sleeve 5, as shown in the figure, the first sleeve 5 is connected with the flat mold 4 in a plug-in manner, and the structure mold 1 is slidably inserted into the first sleeve 5, the relative positions of the structure mold 1, the flat mold 4 and the glass blank 3 can be fixed by using the first sleeve 5, thereby improving the stability of the device and providing convenience for the processing and manufacturing of the microlens array 10. Figure 4

[0060] In the embodiment, the longitudinal sections of the structure mold 1 and the flat mold 4 are both T-shaped, the first sleeve 5 is connected with the flat mold 4 in a plug-in manner, thereby providing stable support for the glass blank 3, and the first sleeve 5 provides a guiding function for the structure mold 1 to apply pressure to the glass blank 3, thereby ensuring the smooth progress of the mold pressing.

[0061] In other embodiments of the present application, the processing device of the microlens array 10 can further comprise a second sleeve 6, which is sleeved on the outside of the first sleeve 5, thereby further improving the structural stability of the device and the manufacturing reliability of the microlens array 10.

[0062] The present application can manufacture a rectangular aperture infrared microlens array 10 with high precision and high consistency, and more importantly, the present application provides an infrared focal plane detector, the array surface of the microlens array 10 is connected with the infrared detector chip 8, a small lens is arranged on each pixel 11 to focus light on the pixel 11, which can increase the sensitivity of the camera by nearly 1 times, the quantum efficiency of the pixel 11 is increased by 1 times in the infrared spectrum range, and the signal-to-noise ratio can be improved, thereby improving the image quality.

[0063] The principles and embodiments of the present application are described by using specific examples, and the above examples are only used to help understand the method and core idea of the present application; meanwhile, for those skilled in the art, the specific embodiments and application range can be changed according to the idea of the present application. In conclusion, the content of the present application should not be understood as a limitation.​

Claims

1. An infrared focal plane detector, comprising: The application relates to an infrared focal plane array, which comprises an infrared detector chip and a microlens array. The microlens array is connected with the infrared detector chip. The microlens array is connected with the infrared detector chip by adhesion. The microlens array is connected with the infrared detector chip by adhesion using optical glue. The application further discloses a manufacturing method of the infrared focal plane array. Step 1: a structure mold with a concave surface is processed, wherein the shape of the concave surface is matched with the array surface of the microlens array. Step 2: the structure mold is placed at the bottom of a glass blank, the concave surface faces the glass blank, the structure mold and the glass blank are heated, pressure is applied to the structure mold, and the glass blank is molded to obtain the microlens array. Step 3: a substrate is connected at the bottom of the microlens array, and the substrate is located at the side far away from the array surface of the microlens array. Step 4: the array surface of the microlens array is adhered to the infrared detector chip. Step 5: the substrate is removed to obtain the infrared focal plane array. In step 1, the concave surface is a spherical surface or a non-spherical spherical crown.

2. The infrared focal plane detector of claim 1, wherein: In step 1, the concave surface is processed by mechanical processing.

3. The infrared focal plane detector of claim 1, wherein: In step 2, the glass blank is made of a chalcogenide glass material.

4. The infrared focal plane detector of claim 1, wherein: In step 3, the substrate is fixed at the bottom of the microlens array by adhesion.

5. The infrared focal plane detector of claim 1, wherein: In step 4, optical glue is coated on the infrared detector chip, and the microlens array is adhered by using the optical glue.

6. The infrared focal plane detector of claim 1, wherein: In step 4, the optical glue is spin-coated on the infrared detector chip.

7. The infrared focal plane detector of claim 6, wherein: ​

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