CN210862938U

CN210862938U - Focal plane detector suitable for curved surface imaging

Info

Publication number: CN210862938U
Application number: CN201921494573.9U
Authority: CN
Inventors: 叶振华; 张伟婷; 陈星�; 刘丰硕; 孙常鸿
Original assignee: Shanghai Institute of Technical Physics of CAS
Current assignee: Shanghai Institute of Technical Physics of CAS
Priority date: 2019-09-10
Filing date: 2019-09-10
Publication date: 2020-06-26
Anticipated expiration: 2029-09-10

Abstract

The utility model provides a focal plane detector suitable for curved surface formation of image, focal plane detector suitable for curved surface formation of image include: a support substrate; and the shaped focal plane array is positioned on the surface of the supporting substrate, and the curved surface shapes of the shaped focal plane array and the supporting substrate are kept consistent. By adopting the structure, light can be always kept focused on the focal plane detector, the imaging effect can be ensured to the maximum extent without complex optical correction calculation, and the structure is suitable for large-field-of-view and large-area-array high-resolution imaging. The preparation method uses the PDMS flexible mould to shape the silicon-based focal plane, uses the ultraviolet curing material and ultraviolet illumination to shape, has simple process, does not need complex and expensive instruments and equipment in the shaping process, and has high preparation efficiency.

Description

Focal plane detector suitable for curved surface imaging

Technical Field

The patent belongs to the technical field of infrared detector chip preparation, and particularly relates to a detector suitable for curved surface imaging and a preparation method thereof.

Background

The infrared imaging detection is the core part of a photoelectric system, and the capability of realizing day and night observation, passive imaging, sunlight interference resistance, atmosphere and battlefield smoke resistance and other environment scattering is obviously superior to that of a visible light system. The large-field high-resolution detection is a key problem in the development of the infrared imaging technology. Modern large-field and high-resolution infrared imaging detection needs to adopt a complex optical system to reduce aberration and improve optical resolution, so that the problems of large volume and weight of a high-resolution system and the like are caused, and application limitation is caused on application of satellite-borne, missile-borne and active attack weapons. The main reason for this problem is that in the photoelectric imaging system, the detector is located at the position close to the focal plane of the image element of the optical system, and since the detector is of a planar structure (generally called focal plane), the focal plane needs to be compensated and corrected by a complex optical system, so as to ensure that the imaging is free from distortion. For a large-field and high-resolution system, the difficulty of distortion correction and the complexity of the system are obviously increased, and the adoption of multiple lenses also obviously increases the optical loss while correcting aberration. Meanwhile, as the detector pursues SWaP more and more in such a conventional solution³(size, weight, power consumption, performance, cost) and is more and more impressive.

In the development of a large-field imaging technology, functions such as an optical lens and the like are integrated in a Dewar-shaped retina infrared focal plane detector, so that high-quality imaging detection of a large field is realized. Bionics has been a lot of inspiring for human beings, and human eyes are an extremely important organ to have guiding significance for detectors, namely preparation of retina-like detectors. By preparing such a kind of retina detector, aberration can be avoided directly, and the retina detector can be used for a large field angle, maintain high detection performance, and further simplify the system.

The human retina structure is a concave surface structure, and a relatively simple optical system can be adopted to realize a large-field high-resolution detection task. If the flexible imaging detector is adopted and adaptive layout is carried out according to the shape of the focal plane of the optical system, the design of the optical system can be greatly simplified, and the high-resolution performance under a large view field is improved. For the second category of superlattice and mercury cadmium telluride detectors, the bending is difficult due to the small mechanical damage threshold, and the silicon-based chip has practical value, so that the research from the silicon-based focal plane detector is very meaningful.

Disclosure of Invention

The purpose of this patent is in order to solve the problem that need compensate the correction aberration through complicated optical system to the focal plane when traditional formation of image, can directly compensate the aberration through such structure of the focal plane detector that is applicable to the curved surface formation of image of this patent to greatly simplified optical system's design, promoted the high resolution performance under the big visual field.

The technical solution of this patent: a focal plane detector structure suitable for curved surface imaging, said focal plane detector structure suitable for curved surface imaging comprising:

the array comprises a supporting substrate and a shaped focal plane array, and is characterized in that the supporting substrate is made of silicon nitride, the thickness of the supporting substrate is not more than 0.5mm, and the shape of a curved surface is consistent with that of the shaped focal plane; the shaped focal plane array is bonded on the surface of the supporting substrate by DW-3 low-temperature epoxy glue, the thickness of the array is not more than 0.1mm, the curvature radius is 20-200 mm, and the range of the F number is 0.9-5.

The beneficial effect that is applicable to the focal plane detector structure of curved surface formation of image in this patent is: by adopting the structure, light can be always kept focused on the focal plane detector, the imaging effect can be ensured to the maximum extent without complex optical correction calculation, and the structure is suitable for large-field-of-view and large-area-array high-resolution imaging.

The patent also relates to a preparation method of the focal plane detector suitable for curved surface imaging, which comprises the following steps:

the chip is prepared on the silicon oxide layer or other sacrificial layers, the chip on the sacrificial layer can be obtained after the preparation which is consistent with the normal process, and the upper chip can be peeled off after the sacrificial layer is completely removed, so that a thin layer array with flexibility is formed. Firstly, the thin layer array is adhered to a support substrate, and then the thin layer array is placed on a PDMS flexible mould with a certain curvature to be shaped. After shaping, an ultraviolet curing material and ultraviolet illumination are adopted for shaping, and finally, a shaped focal plane detector is taken out, and the support substrate is thinned and flattened.

Furthermore, the PDMS flexible mould is in a hemispherical shape, and the shape of the curved surface is consistent with that of the shaped detector array.

The preparation method of the focal plane detector suitable for curved surface imaging has the advantages that: the material of the PDMS to be the shaped flexible template is selected, no heat is generated during the ultraviolet curing, the shape of the PDMS is not affected, namely, the PDMS does not shrink during the curing process, and the PDMS is convenient to peel off after the curing process. The method has simple preparation process, no need of complex and expensive instruments and equipment in the forming process, and high preparation efficiency.

Drawings

Figure 1 is a schematic diagram of the shaped focal plane array of this patent.

FIG. 2 is a schematic diagram of the optical path of the lens of the method of this patent.

In the drawings, the names of the components denoted by the respective reference numerals are as follows: 1 is a support substrate and 2 is a shaped focal plane array.

The specific implementation mode is as follows:

the advantage of a focal plane detector suitable for curved surface imaging over a normal focal plane detector is illustrated below by the optical path principle of the lens, as shown in fig. 1.

When carrying out big visual field high resolution imaging, along with the increase of oblique incident light, the focus point of these light can deviate from ordinary plane focal plane, and the clear formation of image in visual field edge will become very difficult, and moreover, oblique incident angle is bigger, and the focus of formation of image just can keep away from the primary optic axis more, when focus distance plane focal plane surpassed the focal depth, will take place the fuzzy phenomenon of distortion at the image edge. However, if a focal plane detector suitable for curved surface imaging is adopted, the obliquely incident light rays can be focused on the focal plane suitable for curved surface imaging, so that the aberration can be compensated, and the distortion phenomenon can be improved.

Example one

The following will further describe the structure and the preparation method of the present patent by taking an example of pixel pitch of 15 μm, silicon-based chip array of 640 × 512, F number of 0.9, and focal length of 20mm, with reference to the accompanying drawings:

the silicon-based chip on the sacrificial layer can be obtained by preparing the silicon-based chip on the sacrificial layer on a silicon oxide layer or other sacrificial layers in accordance with a normal process, the silicon-based chip on the sacrificial layer can be peeled off after the sacrificial layer is completely removed to form a flexible silicon-based thin layer, the thickness of the thin layer is 0.01mm, the silicon-based thin layer is adhered to a supporting substrate by DW-3 low-temperature epoxy glue, the supporting substrate in the example adopts a silicon nitride material with the thickness of 0.1mm, and then the silicon-based thin layer is placed on a PDMS flexible mold with a certain curvature and shaped, and the PDMS flexible mold in the example is a hemispherical mold with the curvature radius of 20 mm. After shaping, an ultraviolet curing material and ultraviolet illumination are adopted for shaping, and then a shaping focal plane 1 is taken out, as shown in figure 2, wherein 2 is a pixel. And finally, thinning and flattening the supporting substrate, and controlling the thickness to be 0.05 mm.

Example two

The following will further describe the structure and the preparation method of the present patent by taking an example of pixel pitch of 15 μm, silicon-based chip array of 640 × 512, F number of 2, and focal length of 60mm, with reference to the accompanying drawings:

the silicon-based chip on the sacrificial layer can be obtained by preparing the silicon-based chip on the sacrificial layer on a silicon oxide layer or other sacrificial layers in accordance with a normal process, the silicon-based chip on the sacrificial layer can be peeled off after the sacrificial layer is completely removed to form a flexible silicon-based thin layer, the thickness of the thin layer is 0.05mm, the silicon-based thin layer is bonded to a supporting substrate by DW-3 low-temperature epoxy glue, the supporting substrate in the example adopts a silicon nitride material with the thickness of 0.2mm, and then the silicon-based thin layer is placed on a PDMS flexible mold with a certain curvature and shaped, and the PDMS flexible mold in the example is a hemispherical mold with the curvature radius of 60 mm. After shaping, an ultraviolet curing material and ultraviolet illumination are adopted for shaping, and then a shaping focal plane 1 is taken out, as shown in figure 2, wherein 2 is a pixel. And finally, thinning and flattening the supporting substrate, and controlling the thickness to be 0.1 mm.

EXAMPLE III

The following will further describe the structure and the preparation method of the present patent by taking an example of pixel pitch of 15 μm, silicon-based chip array of 640 × 512, F number of 5, and focal length of 150mm, with reference to the accompanying drawings:

the silicon-based chip on the sacrificial layer can be obtained by preparing the silicon-based chip on the sacrificial layer on a silicon oxide layer or other sacrificial layers in accordance with a normal process, the silicon-based chip on the sacrificial layer can be peeled off after the sacrificial layer is completely removed to form a flexible silicon-based thin layer, the thickness of the thin layer is 0.1mm, the silicon-based thin layer is bonded to a supporting substrate by DW-3 low-temperature epoxy glue, the supporting substrate in the example adopts a silicon nitride material with the thickness of 0.5mm, and then the silicon-based thin layer is placed on a PDMS flexible mold with a certain curvature and shaped, and the PDMS flexible mold in the example is a hemispherical mold with the curvature radius of 60 mm. After shaping, an ultraviolet curing material and ultraviolet illumination are adopted for shaping, and then a shaping focal plane 1 is taken out, as shown in figure 2, wherein 2 is a pixel. And finally, thinning and flattening the supporting substrate, and controlling the thickness to be 0.3 mm.

Claims

1. The utility model provides a focal plane detector suitable for curved surface formation of image, includes supporting substrate (1) and figurative focal plane array (2), its characterized in that:

the supporting substrate (1) is made of silicon nitride, the thickness of the supporting substrate is not more than 0.5mm, and the shape of a curved surface is consistent with that of a shaped focal plane; the shaped focal plane array (2) is bonded on the surface of the supporting substrate (1) by DW-3 low-temperature epoxy glue, the thickness of the array is not more than 0.1mm, the curvature radius is 20-200 mm, and the range of the F number is 0.9-5.