Flexible high-energy laser sensing film sensor and preparation method thereof

Abstract

The invention provides a flexible high-energy laser sensing film sensor. The flexible high-energy laser sensing film sensor comprises a sensing film and a laser high-reflection film layer on the surface of the sensing film. The sensing film is composed of a flexible substrate, an upper surface transition layer, a lower surface transition layer, an upper surface thermistor layer, a lower surface thermistor layer, an upper surface lead layer, a lower surface lead layer, an upper surface protection layer and a lower surface protection layer. The thin film type double-sided resistor array is used for monitoring the laser irradiation transient thermal effect in real time, the laser detection threshold value is increased in combination with the laser high-reflection film layer, and rapid and accurate measurement of laser irradiation parameters such as laser power density, light spot size and irradiation position can be achieved; the device solves the problem that the existing devices such as a laser power meter and a laser spot analyzer are limited in light sensing diameter and are difficult to be suitable for large-spot-size laser parameter measurement and laser sensing alarm, and has the advantages of flexibility, large area, simple structure, low cost and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of thin film sensors, and in particular relates to a flexible high-energy laser sensing thin film sensor and a preparation method thereof. Background Art

[0002] With the vigorous development of laser technology, high-energy lasers are widely used in aerospace, weapons and equipment, intelligent manufacturing and other fields. Accurate measurement of laser power density, spot shape, size and other parameters is a necessary prerequisite for the development and utilization of high-energy laser beams. At present, the existing laser power measurement devices are mainly realized by laser power meters based on thermopile. The detectable laser power range is affected by the heat dissipation method of the power meter, and the effective photosensitive diameter is limited, which makes it difficult to meet the measurement of high power density, large spot size and high-energy laser beam power.

[0003] In view of the need for accurate measurement of power density and spot size of high-energy laser beams used in the fields of beam synthesis, laser confrontation, and material laser damage testing, there is still a lack of a high-energy laser measurement device that can be applied to large spot sizes of more than several centimeters and laser powers of more than 100 watts. On the other hand, the development of high-power laser weapons poses a serious threat to satellites, weapons and equipment, etc. Protection against the threat of high-energy laser weapons requires not only the development of laser protection materials based on linear and nonlinear optical principles to improve the strength of laser damage resistance; it also requires a rapid response to laser threats, by detecting signals such as laser power, spot size, and attack position to assess the threat level of laser attacks and issue warning signals for taking corresponding active defense measures. Therefore, the development of a flexible, large-area, and high-energy laser sensing thin film sensor that can detect large spot sizes of centimeters or above can not only be used for accurate measurement of laser parameters in scientific research, but also be coated on the surface of key structures and components to achieve rapid perception and warning of laser attack threats, thereby improving the ability to resist laser strikes. Summary of the invention

[0004] To solve the above problems, the present invention provides a flexible high-energy laser sensing thin film sensor and a preparation method thereof, which can be used for accurate measurement of high-energy laser power density and spot size. The linear resistor array arrangement on the surface of the flexible substrate can realize fast and accurate perception of laser power, spot size and irradiation position, and is suitable for accurate measurement of high-energy laser parameters such as high-energy laser power density and large spot size, and has the advantages of flexibility, large-area arrangement, and integrated protection and perception.

[0005] A flexible high-energy laser sensing film sensor, comprising a sensing film 1 and a laser high-reflection film layer 2 located on the upper surface of the sensing film 1;

[0006] The sensing film 1 is composed of a flexible substrate 101, an upper surface transition layer 102, a lower surface transition layer 106, an upper surface thermistor layer 103, a lower surface thermistor layer 107, an upper surface lead layer 104, a lower surface lead layer 108, an upper surface protective layer 105, and a lower surface protective layer 109; wherein the upper surface transition layer 102, the upper surface thermistor layer 103, the upper surface lead layer 104, and the upper surface protective layer 105 are sequentially covered on the upper surface of the flexible substrate 101, and the lower surface transition layer 106, the lower surface thermistor layer 107, the lower surface lead layer 108, and the lower surface protective layer 109 are sequentially covered on the lower surface of the flexible substrate 101;

[0007] The laser high-reflection film layer 2 is used to reduce the absorption of incident laser by the flexible high-energy laser sensing film sensor and improve the laser power density range that the film sensor can perceive. The laser high-reflection film layer 2 is one of the laser high-reflection films based on all-dielectric multilayer optical film or metal high-reflection film.

[0008] Further, the flexible substrate 101 is a flexible film or foil with a thickness between 10 μm and 500 μm;

[0009] When the flexible substrate 101 is an insulating film or foil, the material of the upper surface transition layer 102 and the lower surface transition layer 106 is one of Ti, Cr, and Ta; when the flexible substrate 101 is a conductive film or foil, the upper surface transition layer 102 and the lower surface transition layer 106 are a combination of multilayer films, wherein the structure of the multilayer film includes an alloy film, an Al2O3 insulating layer, and an adhesion layer prepared on the surface of the Al2O3 insulating layer.

[0010] Furthermore, the upper and lower surface thermistor layers are high-density linear resistor arrays composed of multiple parallel thin film thermistors, and a single thermistor in the linear resistor array is a long strip structure with a width of 20μm to 2mm. The resistor array spacing is 20μm to 2mm, and its length covers the entire sensing area of ​​the sensing film 1.

[0011] Furthermore, the orientation of the linear resistor array arranged on the upper surface thermistor layer 103 and the orientation of the linear resistor array arranged on the lower surface thermistor layer 107 are orthogonal to each other.

[0012] Furthermore, the thickness of the thermistor layer is between 100 nm and 20 μm, and the material is one of the thermistor films such as Pt, Ni, NiCr, etc., which have good resistance temperature coefficient and linearity in a wide temperature range.

[0013] Furthermore, the upper surface lead layer 104 and the lower surface lead layer 108 each include a plurality of leads separated from each other, and the upper surface lead layer 104 and the lower surface lead layer 108 are respectively used to form electrical contact with the upper surface thermistor layer 103 and the lower surface thermistor layer 107 and provide an electrical interface for sensor measurement, one end of each thermistor strip in the linear resistor array is respectively connected to a single lead to form electrical contact, and the other end of the thermistor strip is a lead shared by multiple thermistor strips.

[0014] Furthermore, the upper surface protection layer 105 and the lower surface protection layer 109 are polyimide films or oxide / nitride ceramic films.

[0015] Furthermore, when the laser high-reflection film layer 2 is an all-dielectric multilayer optical film, the preferred film layer system is one of HfO2 / SiO2 or Ta2O5 / SiO2 multilayer films, and high reflection in the laser band to be measured is obtained by design optimization of high and low refractive index film materials and thicknesses.

[0016] Furthermore, when the laser high-reflection film layer 2 is a metal high-reflection film, the metal high-reflection film includes a high-reflectivity film and a transparent radiation heat dissipation film on the surface of the high-reflectivity film;

[0017] The high reflectivity film is preferably one of metal aluminum, silver, and gold films, and is used to improve the wide-band laser reflectivity of the flexible high-energy laser sensing film sensor;

[0018] The radiation heat dissipation layer film is one of silicon oxide, aluminum oxide, and halogen oxide transparent infrared high-emissivity films, which is used to increase the heat dissipation capacity of high-energy laser sensing film sensors.

[0019] A method for preparing a flexible high-energy laser sensing thin film sensor comprises the following steps:

[0020] S1: preparation of flexible substrate 101;

[0021] S2: prepare the lead layer on the upper and lower surfaces and pattern them;

[0022] S3: depositing and patterning transition layer and thermistor layer;

[0023] S4: surface coating protective layer;

[0024] S5: electrical interface enhancement processing;

[0025] S6: Preparation of laser high reflective film layer 2.

[0026] Beneficial effects:

[0027] 1. The present invention provides a flexible high-energy laser sensing thin film sensor, comprising a sensing film and a laser high-reflection film layer on the surface of the sensing film, wherein the sensing film is composed of a flexible substrate and a transition layer, a thermistor layer, a lead layer, and a protective layer prepared on the upper and lower surfaces of the flexible substrate, wherein the transition layer and the thermistor layer are arranged in a linear resistor array, and the arrangement directions of the upper and lower surface resistor arrays are 90° to each other; the laser high-reflection film layer is located on the surface of the sensing film, and is used to improve the laser reflectivity of the thin film sensor and improve the laser sensing damage threshold; it can be seen that the present invention can realize rapid and accurate measurement of laser irradiation parameters such as laser power density, spot size, and irradiation position by arranging row / column resistor linear arrays on the upper and lower surfaces of the flexible substrate, thereby solving the problem that the current laser power meter, laser spot analyzer and other devices have limited photosensitive diameters and are difficult to be applied to large spot size laser parameter measurement and laser sensing alarm, and has the advantages of simple structure and low cost.

[0028] 2. The present invention provides a flexible high-energy laser sensing method. By integrating a laser high-reflection layer on the surface of the sensor film, the laser damage threshold of the sensor film can be greatly improved, making it suitable for the perception and warning of high-power density energy lasers. Through the integrated design of protection and perception, it has important application prospects in the fields of satellite safety and so on. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is an overall schematic diagram of the flexible high-energy laser sensing thin film sensor of the present invention.

[0030] Figure 2 This is a cross-sectional schematic diagram of a first implementation of the flexible high-energy laser sensing thin film sensor of the present invention.

[0031] Figure 3 It is a cross-sectional schematic diagram of the second implementation method of the flexible high-energy laser sensing thin film sensor of the present invention.

[0032] Figure 4 Schematic diagram of the arrangement of upper and lower surface resistor arrays in the flexible high-energy laser sensing thin film sensor.

[0033] Figure 5 This is a time-varying curve of the normalized resistance of the upper surface resistor array obtained in the first embodiment of the flexible high-energy laser sensing thin film sensor.

[0034] Figure 6 A Gaussian fitting curve of the normalized resistance of the upper surface resistor array is obtained in the specific embodiment 1 of the flexible high-energy laser sensing thin film sensor of the present invention.

[0035] Figure 7 The relationship between the normalized resistance Gaussian fitting half-width and the spot radius of the resistor array in the specific embodiment 1 of the flexible high-energy laser sensing thin film sensor of the present invention.

[0036] 1-sensing film; 101-flexible substrate; 102-upper surface transition layer; 103-upper surface thermistor layer; 104-upper surface lead layer; 105-upper surface protective layer; 106-lower surface transition layer; 107-lower surface thermistor layer; 108-lower surface lead layer; 109-lower surface protective layer; 2-laser high reflection film layer; 201-Ta2O5 film; 202-SiO2 film; 203-metal high reflection film; 204-radiation heat dissipation layer. DETAILED DESCRIPTION

[0037] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application.

[0038] The purpose of the present invention is to provide a flexible high-energy laser sensing thin film sensor, which realizes laser sensing by preparing a high-density arranged linear resistor array on a flexible film substrate, and integrates a laser high-reflection film layer on the surface of the sensing film to improve the anti-laser damage threshold, thereby realizing accurate measurement of parameters such as high-energy laser power density and spot size.

[0039] refer to Figure 1 , Figure 2 , a flexible high-energy laser sensing film sensor provided by the present invention comprises a sensing film 1 and a laser high-reflection film layer 2 located on the surface of the sensing film;

[0040] The sensing film is used to sense parameters such as laser power, spot size, and irradiation position in real time, and is composed of a flexible substrate and a transition layer, a thermistor layer, a lead layer, and a protective layer located on the upper and lower surfaces of the flexible substrate. Specifically, the sensing film 1 is composed of a flexible substrate 101, an upper surface transition layer 102, a lower surface transition layer 106, an upper surface thermistor layer 103, a lower surface thermistor layer 107, an upper surface lead layer 104, a lower surface lead layer 108, an upper surface protective layer 105, and a lower surface protective layer 109; wherein the upper surface transition layer 102, the upper surface thermistor layer 103, the upper surface lead layer 104, and the upper surface protective layer 105 are sequentially covered on the upper surface of the flexible substrate 101, and the lower surface transition layer 106, the lower surface thermistor layer 107, the lower surface lead layer 108, and the lower surface protective layer 109 are sequentially covered on the lower surface of the flexible substrate 101;

[0041] The laser high-reflection film layer 2 is used to reduce the absorption of incident laser by the flexible high-energy laser sensing film sensor and improve the laser power density range that the film sensor can perceive. The laser high-reflection film layer 2 is preferably one of the laser high-reflection films based on all-dielectric multilayer optical film or metal high-reflection film.

[0042] When the laser high-reflection film layer 2 is an all-dielectric multilayer optical film, the preferred film layer system is one of HfO2 / SiO2 or Ta2O5 / SiO2 multilayer films. High reflection in the laser band to be measured is obtained by design optimization of high and low refractive index film materials and thickness.

[0043] When the laser high-reflection film layer 2 is a metal high-reflection film, the metal high-reflection film includes a high-reflectivity film and a transparent radiation heat dissipation film on the surface of the high-reflectivity film; the high-reflectivity film is preferably one of metal aluminum, silver, and gold films, which is used to improve the wide-band laser reflectivity of the flexible high-energy laser sensing film sensor; the radiation heat dissipation layer film is preferably one of silicon oxide, aluminum oxide, and hafnium oxide transparent infrared high-emissivity films, which is used to increase the heat dissipation capacity of the high-energy laser sensing film sensor.

[0044] The upper surface transition layer 102 and the lower surface transition layer 106 are deposited on the upper and lower surfaces of the flexible substrate 101 by thin film preparation processes such as evaporation and sputtering, with a thickness between 10nm and 5μm. They can be a single layer or a combination of multiple layers of thin films. They are mainly used to enhance the adhesion of the two thermistor layers prepared on the upper and lower surfaces of the flexible substrate 1, and provide an insulating layer when the flexible substrate 101 is a conductive metal foil.

[0045] In order to improve the stability and environmental applicability of the thin film sensor, the flexible substrate 101 is a flexible film or foil with a thickness of 10μm to 500μm, such as polyimide film, stainless steel foil, pure nickel and nickel-based alloy foil, mica, etc.; wherein, when the flexible substrate 101 is an insulating substrate such as polyimide and mica, the transition layer is used to enhance the adhesion between the thermistor film and the flexible substrate, and the upper and lower surface transition layers are preferably made of one of materials such as Ti, Cr, and Ta; when the flexible substrate 101 is a conductive foil such as stainless steel foil, pure nickel and nickel-based alloy foil, the upper and lower surface transition layers are a combination of multilayer films, which are used to enhance the insulation and adhesion between the metal substrate 101 and the thermistors 103 and 107, and the preferred materials are alloy films such as NiCoCrAlY and FeCrAlY, and an Al2O3 insulating layer is formed by high-temperature aluminum precipitation oxidation, and an adhesion layer such as Ti, Cr, and Ta is prepared on the surface of the insulating layer to form a multilayer structure.

[0046] refer to Figure 4, the upper surface thermistor layer 103 and the lower surface thermistor layer 107 in a flexible high-energy laser sensing thin film sensor provided by the present invention are prepared above the upper surface transition layer 102 and the lower surface transition layer 106. Among them, the upper surface thermistor layer 103 is arranged on the upper surface of the flexible substrate 101 in a high-density linear resistor array after patterning, and a single thermistor in the resistor array is a long strip structure with a width of 20μm to 2mm, and the length covers the entire sensing area of ​​the sensing film. The number of thermistors in the resistor array is preferably 10 to 256, and the lower surface thermistor layer 107 is arranged on the upper surface of the flexible substrate 101 in a high-density linear resistor array with the same array size as the upper surface thermistor layer 103 after patterning, and the linear resistor array arranged on the upper surface thermistor layer 103 is orthogonal to the linear resistor array arranged on the lower surface thermistor layer 107. ;

[0047] Furthermore, the thickness of the upper surface thermistor layer 103 and the lower surface thermistor layer 107 is between 100 nm and 20 μm, and the preferred material is a thermistor film such as Pt, Ni, NiCr, etc. having good resistance temperature coefficient and linearity in a wide temperature range.

[0048] The upper surface lead layer 104 and the lower surface lead layer 108 are used to form reliable electrical contact with the upper surface thermistor layer 103 and the lower surface thermistor layer 107 respectively and provide an electrical interface for sensor measurement. The upper surface lead layer 104 and the lower surface lead layer 108 are patterned into multiple leads separated from each other. One end of each thermistor strip in the linear resistor array is connected to a single lead to form electrical contact, and the other end of the thermistor strip is a lead shared by multiple thermistor strips. For a linear array composed of n thermistor strips, the total number of lead strips is between n+1 and 2n.

[0049] The upper surface protection layer 105 and the lower surface protection layer 109 can be one of insulating films such as polyimide film, oxide / nitride ceramic film, etc. The upper surface protection layer 105 and the lower surface protection layer 109 are respectively located on the upper surface of the upper surface thermistor layer 103 and the lower surface thermistor layer 107, and are used to form passivation protection for the two thermistor layers.

[0050] The laser high-reflection film layer 2 is located on the upper surface of the sensing film 1 and is a type of laser high-reflection film based on an all-dielectric multilayer optical film or a metal high-reflection film. It is used to significantly reduce the absorption of incident lasers and improve the laser damage threshold of flexible high-energy laser sensing film sensors.

[0051] refer to Figure 2Among them, the laser high-reflection film layer 2 in a flexible high-energy laser sensing thin film sensor provided by the present invention is an all-dielectric multilayer optical film, and the film layer system is a Ta2O5 / SiO2 multilayer film. By utilizing the refractive index difference between the Ta2O5 film 201 and the SiO2 film 202, and optimizing the design of the multilayer film system combination and thickness, a high reflection capability of more than 95% in the 1.064μm laser wavelength band is obtained.

[0052] Furthermore, the present invention provides a method for preparing a flexible high-energy laser sensing thin film sensor, comprising the following steps:

[0053] Step 1: Preparation of the flexible substrate 101: using a 50 μm thick polyimide substrate, inspecting and cleaning it to remove surface contaminants;

[0054] Step 2: Preparing and patterning the lead layer on the upper and lower surfaces: Using a two-step process of sputtering + electroplating, a Cu lead film with a thickness of 8 μm is deposited on the upper and lower surfaces of the flexible substrate 101; using an exposure and development method, the pattern on the film is transferred to the flexible substrate 101, and the etching and film stripping processes are completed to form a lead pattern;

[0055] Step 3: Deposition and patterning of transition layer and thermistor layer: magnetron sputtering is used to prepare an upper surface transition layer 102, an upper surface thermistor layer 103, a lower surface transition layer 106, and a lower surface thermistor layer 107 on the upper surface and the lower surface of the flexible substrate 101, respectively, and patterning them; wherein, the upper surface transition layer 102 and the lower surface transition layer 106 are Ti thin films, and the upper surface thermistor layer 103 and the lower surface thermistor layer 107 are Pt thin films. After magnetron sputtering is used to complete the double-sided deposition of 30nmTi+200nmPt thin films, laser etching technology is used to remove excess Ti+Pt thin films on the surface of the flexible substrate 101 to form linear resistor arrays on the upper and lower surfaces;

[0056] In another embodiment, the upper surface thermistor layer 103 and the lower surface thermistor layer 107 are prepared by screen printing process to directly obtain a linear resistor array, which can omit the subsequent patterning process of the upper surface thermistor layer 103 and the lower surface thermistor layer 107.

[0057] That is to say, the thermistor layer can be prepared by various preparation processes such as evaporation, sputtering, and screen printing. When the thermistor thin film is obtained by evaporation, sputtering, etc., in order to realize the preparation of a large-area sensing film on a flexible substrate, the preferred graphic method is laser etching to remove excess thermistor thin film material; when the thermistor thick film is obtained by screen printing, the printing process can simultaneously realize the graphic process.

[0058] Step 4: Surface coating with protective layer: After the lead layer and thermistor layer processes are completed, an insulating upper surface protective layer 105 and a lower surface protective layer 109 are respectively coated on the upper and lower surfaces of the flexible substrate 101 to expose the electrical interface area; both protective layers are polyimide films, and a lamination process is performed after lamination;

[0059] Step 5: Electrical interface enhancement: Add a structural reinforcement layer to the electrical interface and perform gold immersion treatment on the exposed lead position to improve the structure and electrical reliability of the electrical interface;

[0060] Step 6: Preparation of laser high reflective film layer 2: Using ion beam sputtering, Ta2O5 / SiO2 multilayer films are alternately plated on the upper surface of the sensor film 1 according to the multilayer film design film system to improve the laser reflectivity of the sensor film at a specific wavelength of 1.064μm.

[0061] It should be noted that in another specific implementation, the deposition of two transition layers and two thermistor layers in step 3 of the preparation method can be completed before the preparation and patterning of two lead layers on the upper and lower surfaces in step 2, and the process goal of forming a reliable electrical connection between the lead layer and the thermistor layer can be achieved.

[0062] refer to Figure 3 , a flexible high-energy laser sensing thin film sensor provided in the second embodiment of the present invention can use a metal high-reflection film with a transparent oxide radiation heat dissipation layer on the surface as the laser high-reflection film layer, which can achieve the same laser sensing goal as the first embodiment. Its preparation method is to replace step 6: preparation of the laser high-reflection film layer 2 with: using magnetron sputtering to coat an Ag film on the upper surface of the sensing film 1 as a metal high-reflection film 203, and further, coating a transparent aluminum oxide / silicon oxide radiation heat dissipation layer 204 with a thickness of 1μm to 10μm on the surface of the Ag film, while obtaining a wide-band laser high reflection capability, improve the infrared emissivity of the thin film sensor, and further enhance the laser loss threshold of the thin film sensor.

[0063] refer to Figure 5 , Figure 6 , Figure 7 The present invention provides a method for measuring laser parameters of a flexible high-energy laser sensing thin film sensor. Specifically, when the laser irradiates the thin film sensor coated with a laser high-reflection film layer, the laser thermal effect causes the temperature of the irradiated area of ​​the thin film sensor to rise rapidly, thereby causing the resistance value of the linear resistor array in the thin film sensor to change. In a specific embodiment, the normalized resistance change trend of the multiple resistor arrays on the upper surface under laser irradiation is shown in FIG. Figure 5 By measuring the normalized change in the resistance of the upper and lower surface arrays, the laser parameter information such as laser irradiation power, spot size, and irradiation center position can be obtained through the laser parameter inversion algorithm. The specific inversion process includes:

[0064] S1: The multi-channel data acquisition circuit continuously and rapidly acquires the resistance values ​​of the thermistors of the linear resistor array on the upper and lower surfaces and obtains the resistance value benchmark when the laser is not irradiated;

[0065] S2: When it is detected that the change in the resistance value of one or more resistors in the linear resistor array is greater than 0.1%, it is determined that the laser irradiation has started, and the inversion algorithm starts to run;

[0066] S3: Select a certain time after the laser starts irradiating, such as 1 second after the row resistance array and the normalized change of the column resistance are collected for Gaussian fitting, such as Figure 6 As shown in the figure, the Gaussian center position obtained by fitting is the laser irradiation center position, and the half-height width of the Gaussian distribution obtained is proportional to the laser spot size, as shown in Figure 7 As shown, the laser spot size can be obtained: laser spot diameter D = A × w, where A is the proportional coefficient and w is the half-height width of the Gaussian distribution;

[0067] S4: Perform differential processing on the resistance values ​​of thermistor array collected within a period of time to obtain resistance change rate data, select the maximum resistance change rate of a single resistor in the row and column array during laser irradiation, and combine the relationship between the maximum resistance change and the laser spot size and laser power density to obtain the laser power density: Laser power density in, is the maximum value of resistance change rate;

[0068] S5: When it is detected that the resistance change rate of a single resistor or multiple resistor arrays is less than 0, it is detected that the laser is turned off and the sensor is in standby mode.

[0069] It can be seen that the flexible high-energy laser sensing thin film sensor provided by the present invention adopts a flexible film as a substrate, and can realize accurate perception of parameters such as laser power density, spot size, and irradiation position by preparing thermistor layers on the upper and lower surfaces and patterning them into a linear resistor array distributed in rows and columns; further, in order to improve the laser damage threshold of the thin film sensor, a laser high-reflection film layer is integrated on the surface of the thin film sensor, which can increase the detectable laser power density of the thin film sensor to 200W / cm 2 above, making it suitable for high power density 0.1W / cm 2 ~200W / cm 2 , high-energy laser sensing applications with large spot sizes of 3mm to 100mm, and has integrated laser protection and perception functions. It has excellent prospects in applications such as high-energy laser beam detection and characterization, laser weapon attack protection and perception.

[0070] Of course, the present invention may have many other embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art may certainly make various corresponding changes and modifications based on the present invention, but these corresponding changes and modifications should all fall within the scope of protection of the claims attached to the present invention.

Claims

1. A flexible high-energy laser sensing thin film sensor, characterized in that: It comprises a sensing film (1) and a laser high-reflection film layer (2) located on the upper surface of the sensing film (1); The sensing film (1) is composed of a flexible substrate (101), an upper surface transition layer (102), a lower surface transition layer (106), an upper surface thermistor layer (103), a lower surface thermistor layer (107), an upper surface lead layer (104), a lower surface lead layer (108), an upper surface protective layer (105), and a lower surface protective layer (109); wherein the upper surface transition layer (102), the upper surface thermistor layer (103), the upper surface lead layer (104), and the upper surface protective layer (105) are sequentially covered on the upper surface of the flexible substrate (101), and the lower surface transition layer (106), the lower surface thermistor layer (107), the lower surface lead layer (108), and the lower surface protective layer (109) are sequentially covered on the lower surface of the flexible substrate (101); The laser high-reflection film layer (2) is used to reduce the absorption of incident laser by the flexible high-energy laser sensing thin film sensor, thereby increasing the laser power density range that can be sensed by the thin film sensor. The laser high-reflection film layer (2) is a type of laser high-reflection film based on an all-dielectric multilayer optical film or a metal high-reflection film.

2. A flexible high-energy laser sensing thin film sensor as claimed in claim 1, characterized in that: The flexible substrate (101) is a flexible film or foil with a thickness between 10 μm and 500 μm; When the flexible substrate (101) is an insulating film or foil, the material of the upper surface transition layer (102) and the lower surface transition layer (106) is one of Ti, Cr, and Ta; when the flexible substrate (101) is a conductive film or foil, the upper surface transition layer (102) and the lower surface transition layer (106) are a combination of multilayer films, wherein the structure of the multilayer film includes an alloy film, an Al2O3 insulating layer, and an adhesion layer prepared on the surface of the Al2O3 insulating layer.

3. A flexible high-energy laser sensing thin film sensor as claimed in claim 1, characterized in that: The upper and lower surface thermistor layers are high-density linear resistor arrays composed of multiple parallel thin film thermistors. A single thermistor in the linear resistor array is a long strip structure with a width of 20 μm to 2 mm. The resistor array spacing is 20 μm to 2 mm, and its length covers the sensing area of ​​the entire sensing film (1).

4. A flexible high-energy laser sensing thin film sensor as described in claim 1 or 3, characterized in that: The orientation of the linear resistor array arranged on the upper surface thermistor layer (103) and the orientation of the linear resistor array arranged on the lower surface thermistor layer (107) are mutually orthogonal.

5. A flexible high-energy laser sensing thin film sensor as described in claim 1 or 3, characterized in that: The thickness of the thermistor layer is between 100 nm and 20 μm, and the material is one of the thermistor films such as Pt, Ni, NiCr, etc., which have good resistance temperature coefficient and linearity in a wide temperature range.

6. A flexible high-energy laser sensing thin film sensor as claimed in claim 1, characterized in that: The upper surface lead layer (104) and the lower surface lead layer (108) each include a plurality of leads separated from each other. The upper surface lead layer (104) and the lower surface lead layer (108) are respectively used to form electrical contact with the upper surface thermistor layer (103) and the lower surface thermistor layer (107) and provide an electrical interface for sensor measurement. One end of each thermistor strip in the linear resistor array is respectively connected to a single lead to form electrical contact, and the other end of the thermistor strip is a lead shared by multiple thermistor strips.

7. A flexible high-energy laser sensing thin film sensor as claimed in claim 1, characterized in that: The upper surface protection layer (105) and the lower surface protection layer (109) are polyimide films or oxide / nitride ceramic films.

8. The flexible high-energy laser sensing thin film sensor according to claim 1, characterized in that: When the laser high-reflection film layer (2) is an all-dielectric multilayer optical film, the preferred film layer system is one of HfO2 / SiO2 or Ta2O5 / SiO2 multilayer films, and high reflection in the laser band to be measured is obtained by optimizing the design of high and low refractive index film materials and thickness.

9. The flexible high-energy laser sensing thin film sensor according to claim 1, characterized in that: When the laser high-reflection film layer (2) is a metal high-reflection film, the metal high-reflection film comprises a high-reflectivity film and a transparent radiation heat dissipation film on the surface of the high-reflectivity film; The high reflectivity film is preferably one of metal aluminum, silver, and gold films, and is used to improve the wide-band laser reflectivity of the flexible high-energy laser sensing film sensor; The radiation heat dissipation layer film is one of silicon oxide, aluminum oxide, and halogen oxide transparent infrared high-emissivity films, which is used to increase the heat dissipation capacity of high-energy laser sensing film sensors.

10. A method for preparing a flexible high-energy laser sensing thin film sensor according to claim 1, characterized in that: The following steps are involved: S1: flexible substrate (101) preparation; S2: prepare the lead layer on the upper and lower surfaces and pattern them; S3: depositing and patterning transition layer and thermistor layer; S4: surface coating protective layer; S5: electrical interface enhancement processing; S6: Preparation of laser high reflective film layer (2).

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