Ultraviolet discharge imaging device and method

Abstract

The invention discloses an ultraviolet discharge imaging device and method, and the device comprises an ultraviolet imaging module which is used for converting an optical signal into a digital signal; the storage module is connected with the ultraviolet imaging module and is used for storing the digital signal; wherein the ultraviolet imaging module comprises a first layer of coating film, a second layer of coating film and a CMOS image sensor which are connected in sequence, the first layer of coating film is used for filtering a non-ultraviolet light part, and the second layer of coating film is used for receiving a filtered optical signal and enhancing an ultraviolet light part in the optical signal; and the CMOS sensor is used for converting the enhanced optical signal into a digital signal. The performance, such as quantum efficiency and response speed, of the ultraviolet detector is improved, noise and cost are reduced, and the device is more suitable for on-site rapid detection and real-time monitoring.

Description

Technical Field

[0001] The invention relates to the field of ultraviolet discharge imaging, and in particular to an ultraviolet discharge imaging device and method. Background Art

[0002] The UV sensitivity enhancement technology is mainly achieved by adding fluorescent materials in front of silicon photodiodes. These materials emit visible light after being excited by UV radiation, thereby improving the detection efficiency of UV radiation. The main enhancement materials currently used include organic fluorescent materials such as coronene and Lumogen, inorganic phosphorescent coatings, and quantum dot materials. These materials can significantly improve the quantum efficiency of the UV band. For example, the quantum efficiency of Lumogen film in the UV band is increased by 1.6 times. The rare earth manganese-doped Zn2SiO4 UV enhancement film is suitable for UV-enhanced CCD / CMOS image sensors, and quantum dot materials have attracted much attention due to their strong UV absorption, high fluorescence quantum yield, adjustable band gap, and good stability.

[0003] Although UV photosensitivity enhancement technology has made significant progress in improving UV detection efficiency, there are still some problems, mainly including high cost, which makes single chips and complete sets of equipment expensive; low imaging efficiency, which requires increasing the sensitivity by increasing the photosensitive area, which limits the portability and flexibility of the equipment; relatively low frame rate, which may affect the effect of real-time monitoring; and the supporting optical lens is large in size and high in cost, which increases the complexity and cost of the overall system. Summary of the invention

[0004] In view of this, the main purpose of the present invention is to solve the problems of low ultraviolet band conversion efficiency, high noise, large equipment size, high cost, high equipment precision and non-portability in the prior art.

[0005] The present invention provides an ultraviolet discharge imaging device, comprising:

[0006] An ultraviolet imaging module, the ultraviolet imaging module is used to convert the optical signal into a digital signal; and

[0007] A storage module connected to the ultraviolet imaging module, the storage module being used to store the digital signal;

[0008] Among them, the ultraviolet imaging module includes a first layer of coating, a second layer of coating and a CMOS image sensor connected in sequence, the first layer of coating is used to filter the non-ultraviolet light part, the second layer of coating is used to receive the filtered light signal and enhance the ultraviolet light part in the light signal, and the CMOS sensor is used to convert the enhanced light signal into a digital signal.

[0009] In some embodiments of the present invention, the first coating layer includes a low refractive index film material, a substrate and a high refractive index film material.

[0010] In some embodiments of the present invention, the high refractive index film material is hafnium oxide, the low refractive index film material is magnesium fluoride, and the substrate is ultraviolet fused quartz.

[0011] In some embodiments of the present invention, the second coating layer is a 68-layer film system structure, which is composed of a 31-layer passband film system and a 37-layer cutoff band film system, which are respectively plated on both sides of the substrate, specifically:

[0012] Air|c(1.2H 1.8L 1.0H 1.0L 1.0H 1.3L 1.7H 1.1L 1.0H 1.0L 1.0H 1.7L1.3H 1.1L 1.0H 1.1L 1.4H 1.6L 1.0H 1.0L 1.0H 1.2L 1.8H 1.1L 1.0H 1.1L 0.6H2.2L 1.0H 1.0L 2.2H)|Sub|a(0.5LH 0.5L) 9 b(0.5LH 0.5L) 9 |Air,

[0013] Wherein, Sub is the substrate, i.e., UV fused silica, the incident medium is air, a, b, and c are all designed central wavelengths, L is magnesium fluoride, and H is hafnium oxide.

[0014] In some embodiments of the present invention, a computing module connected to the storage module, the computing module is used to perform image processing on the digital signal and transmit the processing result back to the storage module;

[0015] A transmission module connected to the calculation module and the storage module respectively, and the transmission module is used to transmit the image data to an external device.

[0016] The present invention also provides an ultraviolet discharge imaging method, the method comprising:

[0017] Step S101, external light is transmitted to the ultraviolet imaging module through the lens;

[0018] Step S102, filtering the non-ultraviolet light portion of the external light through the first coating layer to obtain ultraviolet light;

[0019] Step S103, the ultraviolet light reaches the second coating layer, excites the spectrum through the ultraviolet enhancement film, and irradiates the CMOS sensor;

[0020] In step S104, the CMOS sensor obtains the enhanced optical signal, converts the optical signal into a digital signal, and transmits the digital signal to the storage module.

[0021] The present invention provides an ultraviolet discharge imaging device and method, which realizes the miniaturization and portability of the equipment by optimizing the ultraviolet imaging module, including improving the filtering technology and the imaging enhancement technology, and not only improves the performance of the ultraviolet detector, such as the quantum efficiency and the response speed, but also reduces the noise and the cost, making the device more suitable for rapid on-site detection and real-time monitoring. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a structural schematic diagram of an ultraviolet discharge imaging device according to one embodiment of the present invention;

[0023] Figure 2 A flow chart of an ultraviolet discharge imaging method provided by one embodiment of the present invention. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] Example 1

[0026] See also Figure 1 , an ultraviolet discharge imaging device, comprising an ultraviolet imaging module, the ultraviolet imaging module is used to convert an optical signal into a digital signal; and a storage module connected to the ultraviolet imaging module, the storage module is used to store the digital signal; wherein the ultraviolet imaging module comprises a first coating layer, a second coating layer and a CMOS image sensor connected in sequence, the first coating layer is used to filter the non-ultraviolet light part, the second coating layer is used to receive the filtered optical signal and enhance the ultraviolet light part in the optical signal, and the CMOS sensor is used to convert the enhanced optical signal into a digital signal.

[0027] In a specific embodiment, the device also includes: a computing module connected to the storage module, the computing module is used to perform image processing on the digital signal and transmit the processing results back to the storage module; a transmission module connected to the computing module and the storage module respectively, the transmission module is used to transmit the image data to an external device.

[0028] For the UV imaging module, we optimized the design based on the mainstream back-illuminated CMOS image sensor structure, added a multi-layer coated grating at the front of the microlens to increase the transmittance of UV light and cut off stray light, and added a conversion layer at the front of the photosensitive layer to convert UV light into visible light to achieve photosensitivity enhancement. Finally, we designed the image sensor layout and applied it based on the existing UMC 0.18μm CMOS standard process. Specifically:

[0029] In order to obtain a short-wave pass-through filter film with high transmittance in the ultraviolet band and high reflectance in the visible band, the first step is to design an optical thin film system by selecting the substrate and coating materials. Since the transparent area of ​​ultraviolet fused quartz is 190nm-2000nm, the transmittance in the ultraviolet band is relatively high, which meets the design technical indicator of 240nm-400nm high transmittance requirements, and it also has the advantages of stable physical and chemical properties and low thermal expansion coefficient, it is decided to select ultraviolet fused quartz as the substrate material. At 280nm, the refractive index of ultraviolet fused quartz is about 1.5023. Considering the difficulties in accurately controlling the thickness of metal films during the deposition process, the optical properties are sensitive to the deviation of the thickness of the metal layer, and the passband transmittance is low, dielectric film materials are selected to design and prepare ultraviolet thin film gratings. Because the transparent areas of HfO2 and MgF2 are 220nm-12000nm and 110nm-10000nm respectively, they have excellent transparency in the ultraviolet region, meet the design technical index requirements, have good mechanical properties and moisture absorption resistance, and can be evaporated by electron beam evaporation, etc., it was finally determined that hafnium oxide would be used as the high refractive index film material and magnesium fluoride would be used as the low refractive index film material.

[0030] The second layer adopts a multi-half-wave structure to design the ultraviolet film grating, with a low-refractive index film as the spacer layer. The center drift of the filter film is relatively small, and the substrate is adjacent to the high-refractive index film, which can increase its refractive index. The low-refractive index material is matched with it on the air side, which can achieve a good anti-reflection effect. Using the film design software OptiLayer and the Tailun design method, a 68-layer film structure is designed as follows:

[0031] Air|c(1.2H 1.8L 1.0H 1.0L 1.0H 1.3L 1.7H 1.1L 1.0H 1.0L 1.0H 1.7L1.3H 1.1L 1.0H 1.1L 1.4H 1.6L 1.0H 1.0L 1.0H 1.2L 1.8H 1.1L 1.0H 1.1L 0.6H2.2L 1.0H 1.0L 2.2H)|Sub|a(0.5LH 0.5L) 9 b(0.5LH 0.5L) 9 |Air,

[0032] Wherein, Sub is the substrate, i.e., UV fused silica, the incident medium is air, a, b, and c are the designed central wavelengths, L is magnesium fluoride, and H is hafnium oxide. a corresponds to the first film structure in (0.5LH 0.5L), b corresponds to the second film structure in (0.5LH 0.5L), and c corresponds to the third film structure in (1.2H 1.8L 1.0H 1.0L 1.0H 1.3L 1.7H 1.1L 1.0H 1.0L 1.0H1.7L 1.3H 1.1L 1.0H 1.1L 1.4H 1.6L 1.0H 1.0L 1.0H 1.2L 1.8H 1.1L 1.0H 1.1L0.6H 2.2L 1.0H 1.0L 2.2H).

[0033] The function of the third film structure is to filter out light of 280-340nm and below 240nm. The function of the first film structure and the second film structure is to filter out light above 340nm. The combination of the three retains the light of 240-280nm.

[0034] The structure is composed of 31 layers of bandpass film system and 37 layers of cut-off band film system, which are respectively plated on both sides of the substrate to prevent the two film systems from being plated on the same side of the substrate with too many layers, resulting in excessive stress in the film layer and cracking or even film peeling. In order to better perform deep cut-off, the present invention stacks two short-wave pass symmetrical periodic films with different central wavelengths to obtain a deep cut-off band, and obtains a short-wave pass symmetrical periodic film with a central wavelength of λ0.

[0035] The computing module is the control core of the entire system, and generally uses a low-cost FPGA chip. Its functions include acquiring image data output by the CMOS detector, storing the acquired image data, and controlling image data transmission.

[0036] The function of the transmission module is to realize data transmission between the present invention and the external physical device. The transmission module interface receives the control command, transmits it to the calculation module, and accepts the control of the calculation module to output the image data. The interface of the transmission module can be a type-C interface (applicable to mainstream Android / Hongmeng devices and newer Apple devices) or a lighting interface (applicable to older Apple devices).

[0037] The function of the storage module is to store CMOS image data, cache data of the computing module, etc.

[0038] In summary, considering that existing silicon-based CMOS sensors mainly respond to visible light (400-800nm ​​band), this application proposes an innovative back-illuminated CMOS sensor ultraviolet imaging structure design. This design integrates a multi-layer film system structure composed of a low-refractive index film material, a substrate and a high-refractive index film material as an anti-transmittance filter grating, which not only effectively enhances the transmittance of ultraviolet light, but also filters out unnecessary stray light at the OD4 level. In addition, a special fluorescent film is coated on the surface of the photosensitive layer. When the film absorbs ultraviolet light, it can excite visible light, which makes the generated visible light match the optimal response wavelength of the silicon photodiode, thereby significantly improving the quantum efficiency of ultraviolet light to 45%. The imaging quality can be further improved by using a specially designed discharge defect detection algorithm.

[0039] Example 2

[0040] See also Figure 2 , which shows a flow chart of an ultraviolet discharge imaging method of the present application.

[0041] like Figure 2 As shown, the ultraviolet discharge imaging method specifically includes the following steps:

[0042] Step S101, external light is transmitted to the ultraviolet imaging module through the lens;

[0043] Step S102, filtering the non-ultraviolet light portion of the external light through the first coating layer to obtain ultraviolet light;

[0044] Step S103, the ultraviolet light reaches the second coating layer, excites the spectrum through the ultraviolet enhancement film, and irradiates the CMOS sensor;

[0045] In step S104, the CMOS sensor obtains the enhanced optical signal, converts the optical signal into a digital signal, and transmits the digital signal to the storage module.

[0046] In this embodiment, external light is transmitted into the ultraviolet imaging module through the lens; the external light first passes through the first layer of coating and the substrate, and the non-ultraviolet light part is filtered out; the ultraviolet light reaches the second layer of coating, passes through the ultraviolet enhancement film excitation spectrum, and irradiates the CMOS sensor; the CMOS sensor obtains the enhanced ultraviolet light signal (at this time it is not ultraviolet light, but the excitation spectrum generated by the ultraviolet enhancement coating after being irradiated with ultraviolet light), converts the light signal into a digital signal, and transmits it to the storage module.

[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An ultraviolet discharge imaging device, characterized in that: include: An ultraviolet imaging module, wherein the ultraviolet imaging module is used to convert an optical signal into a digital signal; as well as A storage module connected to the ultraviolet imaging module, the storage module being used to store the digital signal; Among them, the ultraviolet imaging module includes a first layer of coating, a second layer of coating and a CMOS image sensor connected in sequence, the first layer of coating is used to filter the non-ultraviolet light part, the second layer of coating is used to receive the filtered light signal and enhance the ultraviolet light part in the light signal, and the CMOS sensor is used to convert the enhanced light signal into a digital signal.

2. The ultraviolet discharge imaging device according to claim 1, characterized in that: The first coating layer includes a low-refractive-index film material, a substrate and a high-refractive-index film material.

3. The ultraviolet discharge imaging device according to claim 2, characterized in that: The high refractive index film material is hafnium oxide, the low refractive index film material is magnesium fluoride, and the substrate is ultraviolet fused quartz.

4. The ultraviolet discharge imaging device according to claim 1, characterized in that: The second coating layer is a 68-layer film system structure, which is composed of a 31-layer bandpass film system and a 37-layer cutoff film system, which are respectively plated on both sides of the substrate, specifically: Air|c(1.2H 1.8L 1.0H 1.0L 1.0H 1.3L 1.7H 1.1L 1.0H 1.0L 1.0H 1.7L 1.3H 1.1L 1.0H 1.1L 1.4H 1.6L 1.0H 1.0L 1.0H 1.2L 1.8H 1.1L 1.0H 1.1L <h2 style=";text-align:left;direction:ltr">0.6H 2.2L 1.0H 1.0L 2.2H)|Sub|a(0.5LH 0.5L)<h2 style=";text-align:left;direction:ltr"> 9 <h2 style=";text-align:left;direction:ltr"> b(0.5LH 0.5L)<h2 style=";text-align:left;direction:ltr"> 9 <h2 style=";text-align:left;direction:ltr"> |Air, Wherein, Sub is the substrate, i.e., UV fused silica, the incident medium is air, a, b, and c are all designed central wavelengths, L is magnesium fluoride, and H is hafnium oxide.

5. The ultraviolet discharge imaging device according to claim 1, characterized in that: A computing module connected to the storage module, the computing module being used to perform image processing on the digital signal and transmit the processing result back to the storage module; A transmission module connected to the calculation module and the storage module respectively, and the transmission module is used to transmit the image data to an external device.

6. The ultraviolet discharge imaging method of the device according to any one of claims 1 to 5, characterized in that: The method comprises: Step S101, external light is transmitted to the ultraviolet imaging module through the lens; Step S102, filtering the non-ultraviolet light portion of the external light through the first coating layer to obtain ultraviolet light; Step S103, the ultraviolet light reaches the second coating layer, excites the spectrum through the ultraviolet enhancement film, and irradiates the CMOS sensor; In step S104, the CMOS sensor obtains the enhanced optical signal, converts the optical signal into a digital signal, and transmits the digital signal to the storage module.

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