Thermoelectric photodetectors, photoelectric power meters, and photoelectric energy meters based on black silicon carbide ceramics

Abstract

The present invention discloses a pyroelectric photodetector based on black silicon carbide ceramics and a pyroelectric optical power meter / pyroelectric optical energy meter using the pyroelectric photodetector. The pyroelectric photodetector includes a heat-conducting plate (21) made of black silicon carbide ceramics, one surface of which is a light-absorbing surface (211). A thermopile (22) or a series-connected conductive metal layer (302) is installed on either side of the heat-conducting plate (21) to form the pyroelectric photodetector. By using black silicon carbide ceramics simultaneously as the heat-conducting plate (21) and the light absorber, the pyroelectric photodetector is directly combined with the thermopile (21) or the series-connected conductive metal layer (302), simplifying the structure of the pyroelectric photodetector. At the same time, black silicon carbide ceramics have a high thermal conductivity coefficient, a small thermal expansion coefficient, high heat resistance, a high laser damage threshold, and the light absorbing surface can be cleaned by polishing, which reduces the failure rate of pyroelectric photodetectors and significantly extends their service life.

Description

[Technical Field]

[0001] The present invention heat Regarding electrophotodetectors, in particular, those realized based on silicon carbide ceramics heat Regarding electrophotodetectors, at the same time, this heat Using an electrophotodetector heat Electric type optical power meter / heat Regarding electric-type optical energy meters. In the following, "pyroelectricity" is a misspelling of "thermal electricity." [Background technology]

[0002] In the prior art, the structure of a pyroelectric laser detector (for example, a laser detector used in pyroelectric photoelectric power meters or pyroelectric photoelectric energy meters manufactured by manufacturers such as Ophir Optronics, Coherent, Gentec-EO, and Laserpoint) is shown in Figure 1. They generally use an aluminum alloy substrate as the heat conduction plate 100, and achieve high absorption of light on the incident surface by placing a dark-colored light-absorbing coating layer 101 on one side of the heat conduction plate 100. On the other side of the heat conduction plate 100, an insulating layer 102 (or an insulating oxide layer directly formed on the surface of the aluminum alloy) is first placed, and then a thermopile 103 (i.e., multiple thermocouples connected in series and attached to the surface of the insulating layer 102) is placed on the surface of the insulating layer 102 to detect the temperature difference generated during heat conduction and to measure the incident light power or light pulse energy.

[0003] However, conventional pyroelectric laser detectors have many drawbacks, including a short lifespan, a high failure rate, and low durability, requiring frequent replacement and maintenance by users. Specifically, conventional pyroelectric laser detectors have the following problems: 1. The dark-colored light-absorbing coating 101 placed on the surface of the light incident surface of the aluminum alloy substrate is highly susceptible to damage from high-energy lasers, resulting in a decrease in light absorption. However, when the surface of the aluminum alloy substrate used as the heat conductive plate 100 is exposed, the light reflectivity increases, causing misalignment of the laser detector. 2. The surface of the dark-colored light-absorbing coating layer 101 is easily contaminated and difficult to clean, which changes the light absorption and causes misalignment of the laser detector. 3. The three layers, the heat conduction plate 100, the dark-colored light-absorbing coating layer 101, and the insulating layer 102, are made of different materials. Because the thermal expansion coefficient of the aluminum alloy substrate is relatively large, the heat conduction plate 100 does not match the material of the insulating layer 102. During use, the thermal expansion and contraction of the insulating layer 102 on the back causes the thermopile 103 to easily detach from the heat conduction plate 100, leading to laser detector failure. 4. Aluminum alloy substrates have a melting point of 500-660°C and cannot withstand high temperatures. Generally, the high-temperature limit of laser detectors based on aluminum alloy substrates does not exceed 300°C, and therefore they cannot withstand optical measurements with relatively high average power.

[0004] In the above-mentioned problem, damage to the dark-colored light-absorbing coating layer 101 is the primary cause of failure and malfunction in numerous pyroelectric laser detectors. Furthermore, pyroelectric laser detectors with such malfunctions can only be replaced and cannot be repaired, resulting in very high operating costs. [Overview of the project] [Problems that the invention aims to solve]

[0005] The main technical problem that this invention aims to solve is to provide a pyroelectric photodetector based on silicon carbide ceramics, which is used for measuring optical power and optical pulse energy.

[0006] Another technical problem that the present invention aims to solve is to provide a pyroelectric photoelectric power meter / pyroelectric photoelectric energy meter using the pyroelectric photodetector described above. [Means for solving the problem]

[0007] To achieve the above objectives, the present invention employs the following technical solutions. According to a first embodiment of the present invention, a pyroelectric photodetector is provided which includes a heat conductive plate made of black silicon carbide ceramic, the entire heat conductive plate being used as a light absorber, one surface of the heat conductive plate being a light absorbing surface, and a thermopile being installed on either side of the heat conductive plate.

[0008] Preferably, the thermopile forms a closed curve around the light incident region. Alternatively, the thermopile and the adiabatic edge together form a closed curve around the light incident region.

[0009] A second embodiment of the present invention provides a pyroelectric photodetector comprising a heat-conducting plate made of black silicon carbide ceramics, and further comprising a conductive metal layer and a heat-dissipating ceramic plate connected in series.

[0010] The entire heat conduction plate is used as a light absorber. One surface of the heat conduction plate is a light absorbing surface, the series-connected conductive metal layer is installed on the other surface of the heat conduction plate, and a heat dissipation ceramic plate is installed on the surface of the series-connected conductive metal layer that is away from the heat conduction plate.

[0011] Preferably, the series-connected conductive metal layers comprise a group of thermocouples composed of a plurality of series-connected thermocouples, and the thermocouple group comprises a plurality of semiconductor groups and a plurality of copper electrode sheets. The semiconductor groups comprise N-type semiconductors and P-type semiconductors, and the plurality of semiconductor groups are connected in series sequentially via a plurality of copper electrode sheets, with the copper electrode sheets at both ends, the leading and trailing ends, forming the positive and negative electrodes.

[0012] Preferably, one surface of the heat-radiating ceramic plate that is away from the electrically conductive metal layers connected in series is metallized.

[0013] Preferably, a heat sink is installed on one surface of the heat-radiating ceramic plate that is away from the electrically conductive metal layers connected in series.

[0014] In the above two types of pyroelectric photodetectors, the black silicon carbide ceramic is formed by sintering black silicon carbide powder.

[0015] Preferably, the black silicon carbide ceramic is formed by sintering black silicon carbide powder by any method during processes such as non-pressure sintering, isostatic pressure sintering such as high temperature, hot press sintering, recrystallization, reaction sintering, and chemical vapor deposition. Among them, a high-pressure sintering environment brings higher density and higher thermal conductivity.

[0016] Preferably, the density of the black silicon carbide ceramic is between 2.6 and 3.2 g / cm 3 and generally, the higher the density, the better its thermal conductivity.

[0017] Preferably, the light absorption surface of the black silicon carbide ceramic is non-mirror-like.

[0018] Preferably, the surface roughness Ra of the light absorption surface of the black silicon carbide ceramic is between 0.8 and 6.3 μm.

[0019] Preferably, the laser damage threshold of the black silicon carbide ceramic exceeds 3 GW / cm with the peak power of a narrow pulse and is at least 200 - 500 J / cm 2 with the high energy of a wide pulse. 2

[0020] According to the third aspect of the embodiment of the present invention, a pyroelectric optical power meter / pyroelectric optical energy meter using the above pyroelectric photodetector is provided.

[0021] ​The pyroelectric photodetector based on black silicon carbide ceramics provided by the present invention comprises a heat conductive plate made of black silicon carbide ceramics, the entire heat conductive plate is used as a light absorber, and one side of the heat conductive plate is a light absorbing surface. In the pyroelectric photodetector structure provided by the present invention, a thermopile is installed on either side of the heat conductive plate (either the light absorbing surface or the side opposite to the light absorbing surface) to constitute the pyroelectric photodetector. In the pyroelectric photodetector of other structures provided by the present invention, a conductive metal layer and a heat dissipation ceramic plate are installed in series on the back of the heat conductive plate to constitute the pyroelectric photodetector. [Effects of the Invention]

[0022] In the pyroelectric photodetector described above, the use of black silicon carbide ceramics as a thermal conductive plate and light absorber replaces the conventional three-layer structure (including an aluminum alloy substrate, a dark-colored light-absorbing coating layer, and an insulating layer) of conventional pyroelectric photodetectors. Therefore, the pyroelectric photodetector is constructed by directly combining black silicon carbide ceramics with a thermopile or a series-connected conductive metal layer, simplifying the structure of the pyroelectric photodetector. At the same time, because black silicon carbide ceramics have high thermal conductivity, a low coefficient of thermal expansion, high heat resistance, a high laser damage threshold, and the light-absorbing surface can be cleaned using a polishing method, the failure rate of the pyroelectric photodetector is reduced and the service life of the pyroelectric photodetector is significantly extended. [Brief explanation of the drawing]

[0023] [Figure 1] This is a schematic diagram of a pyroelectric photodetector using an aluminum alloy substrate as a thermal conductive plate in conventional technology. [Figure 2] This is a schematic diagram of a pyroelectric photodetector using silicon carbide ceramics provided by the present invention as a thermal conductive plate. [Figure 3] This is a schematic diagram of the thermopile structure installed on the surface of a heat conductive plate. [Figure 4] Figures 4a to 4h are schematic structural diagrams of various pyroelectric photodetectors provided by embodiments of the present invention. [Figure 5] This is a schematic diagram of a pyroelectric optical power meter / pyroelectric optical energy meter provided by an embodiment of the present invention. [Figure 6] This is a schematic diagram of another pyroelectric photodetector using silicon carbide ceramics provided by the present invention as a thermal conductive plate. [Modes for carrying out the invention]

[0024] The technical solutions of the present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments.

[0025] As shown in Figure 2, the pyroelectric photodetector based on silicon carbide ceramics provided by an embodiment of the present invention includes a thermal conductive plate 21 made of silicon carbide ceramics. The entire thermal conductive plate 21 is used as a light absorber, and one surface of the thermal conductive plate 21 facing the incident light 10 (the surface with a larger area) is the light-absorbing surface 211. At the same time, a thermopile 22 is installed on either side of the thermal conductive plate 21 to constitute a pyroelectric photodetector. The thermopile 22 may be installed on the light-absorbing surface 211 of the thermal conductive plate 21, or on the other surface 212 of the thermal conductive plate 21 (the surface opposite to the light-absorbing surface 211, also referred to as the back surface 212). Preferably, by installing the thermopile 22 on the back surface 212 of the thermal conductive plate 21, contamination of the thermopile 22 can be prevented. The heat 15 absorbed during the detection process of the pyroelectric photodetector passes through the thermopile 22 and then diffuses outward from the side surface 213 of the heat conduction plate 21. Normally, this heat needs to be dissipated by a heat sink in contact with the heat conduction plate 21.

[0026] As shown in Figure 3, the thermopile 22 is formed by connecting multiple thermocouples in series. The thermopile 22 has a series of bimetallic junctions (including a hot end 22A and a cold end 22B), and a voltage is generated between any two adjacent junctions due to a temperature difference between them. Because multiple nodes are connected in series, the hot end 22A is always on the inside, the hotter side, and the cold end 22B is on the outside, the colder side. Therefore, the radial heat flow in the thermopile 22 generates a voltage at the output end 22C of the thermopile 22 that is proportional to the power input. The incident light 10 is irradiated into the light incident region 25 (i.e., the center of the region enclosed by the thermopile 22 having the shape of a closed curve), and the amount of heat absorbed by the heat conduction plate 21 flows radially and is dissipated from the outer region of the thermopile 22.

[0027] As shown in Figure 2, the pyroelectric photodetector provided by the embodiment of the present invention replaces the conventional three-layer structure of a pyroelectric photodetector (specifically, the aluminum alloy substrate 100, the dark-colored light-absorbing coating layer 101, and the insulating layer 102 shown in Figure 1) with a single-layer material (specifically, an integrated structure of a light absorber and a heat conductive plate made of black silicon carbide ceramics). By using black silicon carbide ceramics simultaneously as the heat conductive plate 21 and the light absorber, the problem in the conventional three-layer structure where the aluminum alloy substrate 100 with high light reflectivity is exposed after the dark-colored light-absorbing coating layer 101 is damaged, leading to inaccurate detection results, is fundamentally resolved. Furthermore, the installation of an insulating layer is omitted, preventing the problem of thermopile detachment due to mismatch in thermal expansion coefficients between the heat conductive plate and the insulating layer.

[0028] The silicon carbide ceramics used in the above structure are formed from silicon carbide powder by a sintering process. Specifically, silicon carbide ceramics are formed by sintering silicon carbide powder using one of the following methods: pressureless sintering, static pressure sintering such as high temperature, hot press sintering, recrystallization, reaction sintering, and chemical vapor deposition. Of these, sintering under high pressure yields higher density and thermal conductivity. It should be noted that the technical solutions provided by the embodiments of the present invention are not intended to protect the sintering process of silicon carbide ceramics or the silicon carbide ceramic body itself, but rather to protect pyroelectric photodetectors manufactured using silicon carbide ceramics as a thermal conductive plate and light absorber. Therefore, even if a denser or more uniform silicon carbide ceramic is obtained by improving the conventional sintering process, it still falls within the scope of protection claimed by the present invention, as long as it is used to manufacture the pyroelectric photodetector provided by the embodiments of the present invention.

[0029] Black silicon carbide ceramics are formed by sintering black silicon carbide powder. Currently, black silicon carbide powder is synthesized using various methods, including the Acheson synthesis method, laser method, and organic precursor method. Of these, the most commonly used method in industry is the Acheson synthesis method, in which quartz sand and coke are placed inside a furnace body, and an appropriate amount of wood chips is added as an additive to prepare black silicon carbide powder. Because the volume of the furnace body is mostly large, the temperature distribution inside the furnace body becomes uneven, and therefore, the performance of the synthesized silicon carbide powder may vary. In addition, the quartz sand and coke used as reaction raw materials may contain metallic impurities such as iron and aluminum and are not very pure. Therefore, the resulting silicon carbide powder may contain impurities. Completely pure silicon carbide powder is often colorless, while silicon carbide doped with a small amount of metallic impurities appears green. As the content of metallic impurities increases, the color of the silicon carbide powder darkens and it appears black. Black silicon carbide has higher toughness than green silicon carbide and is mainly used in the processing of ceramics, refractory materials, and non-ferrous metals. Silicon carbide ceramics, which are sintered from black silicon carbide powder, also appear black and are therefore referred to as black silicon carbide ceramics. In the embodiments of the present invention, black silicon carbide ceramics formed by sintering dark-colored silicon carbide powder are selected and used simultaneously as the heat conductive plate 21 and light absorber of a pyroelectric photodetector. The black silicon carbide ceramics described in the embodiments of the present invention are distinguished from light-colored green silicon carbide ceramics and may include, but are not limited to, dark blue, dark gray, and charcoal gray silicon carbide ceramics. It should be noted that the color of the silicon carbide ceramics used must be black in order to ensure a high light absorption rate.

[0030] Through meticulous research, the inventors concluded that pure silicon carbide materials, possessing certain conductivity and poor insulation, are suitable as semiconductors but unsuitable as a connection base for thermopiles, and therefore unsuitable for use in pyroelectric photodetectors provided by the embodiments of the present invention. Furthermore, ordinary silicon carbide materials lack sufficient density and thermal conductivity, and are therefore unsuitable for fabricating the thermal conductive plate 21 and light absorber of thermoelectric photodetectors. However, silicon carbide ceramics have low conductivity and are suitable as a base for mounting thermopiles. In addition, silicon carbide ceramics have high density and thermal conductivity, making them suitable as the thermal conductive plate 21 and light absorber of thermoelectric photodetectors.

[0031] Furthermore, among silicon carbide materials, the relatively pure green color of silicon carbide is not suitable for light absorption, resulting in poor light absorption and high light reflectivity. The light absorption of black silicon carbide is significantly higher than that of green silicon carbide, and the light reflectivity of black silicon carbide is lower than that of green silicon carbide. Therefore, black silicon carbide ceramics are more suitable as a spectroscopic light-absorbing material, specifically as a heat conduction plate 21 and light absorber for pyroelectric photodetectors.

[0032] In conclusion, compared to pure silicon carbide material and green silicon carbide ceramics, black silicon carbide ceramics have a higher impurity content, resulting in higher resistivity, thermal conductivity, and light absorption, as well as lower surface reflectivity than pure silicon carbide material and green silicon carbide ceramics, making them more suitable for the manufacture of pyroelectric photodetectors.

[0033] In the embodiment of the present invention, black silicon carbide ceramics are used as the heat conductive plate 21. On the one hand, the black color has irreplaceable advantages as a medium for light absorption, while on the other hand, the light-absorbing surface 211 of the black silicon carbide ceramics is not mirror-finished and has a certain surface roughness due to processing. For example, good light absorption can be ensured by controlling Ra to between 0.8 and 6.3 μm. When cleaning the surface of a light absorber made of black silicon carbide ceramics, the particle size of the diamond polishing paste used must also match this surface roughness. By cleaning the light-absorbing surface of the heat conductive plate 21 with a diamond polishing paste having a certain particle size, the surface roughness of the light-absorbing surface can be restored, which is advantageous for light absorption. When processing or cleaning the surface of the light incident region 25 of the light-absorbing surface 211 of the black silicon carbide ceramics, the surface roughness of the detection region (i.e., the light incident region 25) should be matched in order to ensure uniformity of light absorption.

[0034] When manufacturing the thermal conductive plate 21 and light absorber from black silicon carbide ceramics, it should be noted that the amount of impurities contained therein must be such that the resistance of the black silicon carbide ceramics is much higher than the resistance of the thermopile 22 (R black silicon carbide ceramics >> R thermopile), thereby minimizing interference of the thermopile 22 due to the conductivity of the black silicon carbide ceramics. However, the low conductivity of conventional black silicon carbide ceramic materials can satisfy this requirement. Therefore, the thermopile 22 can be directly attached to the back of the black silicon carbide ceramics 21 without the need for an additional insulating layer.

[0035] The density of pure silicon carbide crystals is 3.16–3.2 g / cm³. 3 The density of the silicon carbide ceramics obtained by the sintering process is 2.6-3.2 g / cm³. 3 It is between these two ranges. Preferably, the density of dense black silicon carbide ceramics can reach 98% or more of the theoretical density of silicon carbide ceramics. Generally speaking, the higher the density of black silicon carbide ceramics, the better its thermal conductivity, making it more suitable for the manufacture of pyroelectric photodetectors.

[0036] Through meticulous research, it has been found that the silicon carbide ceramics that meet the requirements of the embodiments of the present invention simultaneously satisfy the following properties: The silicon carbide ceramics themselves are black in color and can absorb laser light without a coating layer, possessing consistently good light absorption properties both on the surface and internally. The silicon carbide ceramics have excellent insulation properties and low electrical conductivity, allowing for direct physical contact with the thermopile 22 without causing short circuits or electrical interference. The silicon carbide ceramics have excellent thermal conductivity, allowing for rapid heat dissipation, thus preventing combustion caused by high-power lasers. The silicon carbide ceramics have a low coefficient of thermal expansion, allowing them to adhere closely to the thermopile, making them less susceptible to thermal expansion cracking and preventing the thermopile from falling off. Furthermore, the silicon carbide ceramics have a high laser damage threshold (see below for specifics), high heat resistance, and do not melt, making them suitable for the manufacture of pyroelectric photodetectors provided by the embodiments of the present invention. In addition, the silicon carbide ceramics have reasonable density and specific heat capacity, ensuring that the pyroelectric photodetector has a sufficient response speed.

[0037] Table 1 is a comparison table of relevant parameters for common silicon carbide ceramics and aluminum alloys. The comparison shows that silicon carbide ceramics have similar properties to aluminum alloys in terms of thermal conductivity, density, and specific heat capacity, while also exhibiting clear application advantages in terms of operating temperature, thermal expansion coefficient, light reflectance, and resistivity compared to aluminum alloys. Therefore, the inventors believe that silicon carbide ceramics are more advantageous than aluminum alloys as thermal conductive plates and light absorbers for laser detectors.

[0038] JPEG0007864350000001.jpg77142

[0039] The following section details the experimental measurements and theoretical calculations performed by the inventors regarding the laser damage threshold of black silicon carbide ceramics.

[0040] Select black silicon carbide ceramics of non-pressure sintering to manufacture a pyroelectric photodetector. The ceramic density is 3.15 g / cm 3 , the silicon carbide content is about 98%, the light absorption rate at a wavelength of 635 nm is about 80%, the thermal conductivity is about 150 W / (m·K), the ceramic thickness is 2 mm, and the surface roughness Ra is 0.8 μm. Conduct experiments as follows.

[0041] The first experiment is a test of short pulses and high peak power. The light source for the test selects a pulsed laser with a wavelength of 1064 nm, a pulse width of 500 ps, and an energy of 200 mJ per single pulse, and performs impact irradiation on the surface of the black silicon carbide ceramic sample under different diameter circular light spots.When the selected diameter of the light spot is 2 mm or 3 mm, slight damage occurs on the surface of the silicon carbide ceramics.When the selected diameter of the light spot is 4 mm or 5 mm, there is no obvious damage on the surface of the silicon carbide ceramics except for slightly whitish spots.Based on this, it is judged that its laser damage threshold is between 3.2 GW / cm² and [5.6 GW / cm²].The laser damage threshold that an aluminum alloy detector with a light absorption coating layer can withstand is generally within 30 MW / cm². For example, the damage threshold of the laser detector of Ophir Optronics is about 3 MW / cm², while the laser damage threshold of the laser detector of Laserpoint is about 30 MW / cm². It can be said that the laser damage threshold of black silicon carbide ceramics is more than 100 times higher than this. 2 within, for example, the damage threshold of the laser detector of Ophir Optronics is about 3 MW / cm 2 while the laser damage threshold of the laser detector of Laserpoint is about 30 MW / cm [[ID=?]] 2 is. The laser damage threshold of black silicon carbide ceramics can be said to be more than 100 times higher than this. 2 [[ID=?]] 2 is. The laser damage threshold of black silicon carbide ceramics can be said to be more than 100 times higher than this.

[0042] It should be noted that there seems to be some missing or incorrect information in the original text, especially in the part where the unit in "between 3.2GW / cm 2 and [5.6GW / cm 2 " is incomplete, and there are also some unclear or incorrect references in the later part. The translation is done based on the existing text as accurately as possible.After the above experiment, manually polishing the surface of the impact-irradiated silicon carbide ceramic sheet with a 600-mesh diamond polishing paste easily removed color unevenness at the 4mm and 5mm light spot locations. However, minor surface damage remained at the 3mm light spot, and damage of some depth was present at the 2mm light spot. This further confirmed the judgment regarding the laser damage threshold. This also demonstrates that the surface of silicon carbide ceramics contaminated by powerful lasers can be cleaned and restored using a simple polishing process, thereby improving the reusability and long-term economics of the laser detector. In conventional pyroelectric photodetectors, if the coating layer on the surface of the aluminum alloy substrate becomes contaminated, it cannot be cleaned and restored, and the only option is to repair and replace the entire laser detector.

[0043] The second experiment was a broad-pulse, high-energy test. At a room temperature of 20°C, a 200J 808nm semiconductor laser was used in a broad-pulse state of 2ms to irradiate a 2mm thick silicon carbide ceramic surface with a 10mm x 10mm light spot area. The maximum local temperature in the irradiated area reached approximately 300°C, but no material damage occurred. This indicates that, in a broad-pulse state, the energy damage threshold is 200J / cm². 2 This indicates that it exceeds [a certain value]. Theoretically, if a 10mm x 10mm x 2mm silicon carbide ceramic is used, its density would be 3.15 g / cm³. 3 Assuming a specific heat capacity of 800 J / (kg·K) and a light absorption rate of 85%, if the temperature rises to 900°C (at this point, there is no material damage to the silicon carbide), the theoretically acceptable light pulse energy E is 900 × (800 / 1000) × (1 × 1 × 0.2 × 3.15) / 85% = 534 J. At this time, the laser energy density is 534 J / cm². 2 It reaches that point. In other words, its theoretical laser damage threshold is 500 J / cm². 2 It exceeds this. The laser damage threshold that an aluminum alloy substrate with a light-absorbing coating layer can withstand is generally 50 J / cm². 2Within this range, for example, the damage threshold of Ophir Optronics' laser detector is approximately 10 J / cm². 2 The damage threshold for Laserpoint's laser detector is approximately 36 J / cm². 2 This is detector damage. When the pulse is wide and high-energy, the damage threshold for silicon carbide ceramics is thought to increase tenfold compared to this.

[0044] Therefore, by using black silicon carbide ceramics as the thermal conductive plate and light absorber of a pyroelectric photodetector, the optical damage threshold of the laser detector is significantly improved, thereby increasing its lifespan and durability, making it highly suitable for detecting ultra-high power light or pulsed energy.

[0045] The structure of the pyroelectric photodetector provided by the embodiments of the present invention will be schematically described below with reference to Figures 2 to 4. The following embodiments are used solely to illustrate the structure of the pyroelectric photodetector and do not constitute limitations on the specific structure.

[0046] As shown in Figures 2 and 3, the pyroelectric photodetector based on silicon black carbide ceramics provided by an embodiment of the present invention comprises a thermal conductive plate 21 made of silicon black carbide ceramics, the entire thermal conductive plate 21 being used as a light absorber. One surface of the thermal conductive plate 21 is a light-absorbing surface 211. A thermopile 22 is installed on one surface of the thermal conductive plate 21, constituting a pyroelectric photodetector. The thermopile 22 can be installed on the light-absorbing surface 211 of the thermal conductive plate 21, or it may be installed on the other surface 212 of the thermal conductive plate 21 (the surface opposite to the light-absorbing surface 211, referred to as the back surface). In order to prevent contamination of the thermopile 22, it is preferable that the thermopile 22 be installed on the back surface 212 of the thermal conductive plate 21.

[0047] In an embodiment of the present invention, the thermopile 22 is positioned outside the light incidence region 25 of the heat conduction plate 21, and the area outside the thermopile 22 is a heat dissipation region 24 (see the region marked c in Figures 4a to 4h). The amount of heat absorbed in the light incidence region 25 is dissipated to the outside through the thermopile 21 (in Figures 4a to 4h, the direction of heat diffusion inside the light incidence region 25 is indicated by black arrows). The hot end 22A of the thermopile 22 is positioned on the inside of the region where the thermopile 22 is located (closer to the light incidence region 25), and the cold end 22B of the thermopile 22 is positioned on the outside of the region where the thermopile 22 is located (closer to the heat dissipation region 24), and both ends of the thermopile 22 are drawn out to form output ends 22C. The thermopile 22 is formed by connecting multiple nodes in series to increase its output voltage, which is proportional to the temperature difference generated by the amount of heat flowing through the hot end 22A and cold end 22B of the thermopile 22. By detecting the output voltage, the power and energy of the incident light can be detected.

[0048] When an insulating edge 23 is provided on the heat conduction plate 21, the thermopile 22 and the insulating edge 23 are enclosed in a closed shape. The insulating edge 23 is used to prevent the amount of heat absorbed in the light incident region 25 from diffusing outward from the position of the insulating edge 23. This is achieved by not allowing the heat conduction plate 21 at this position to come into contact with the heat sink, thereby allowing all the heat to flow through the thermopile 22. When an insulating edge is not provided on the heat conduction plate 21, the thermopile 22 is enclosed in a closed shape, ensuring that all the heat flows through the thermopile 22. Since all the heat absorbed by the heat conduction plate 21 flows through the thermopile 22 (as long as the incident light 10 is irradiated within the inner circle of the thermal coupling 22A), the response of the pyroelectric photodetector is largely independent of the size and position of the incident beam. When the beam is close to the edge of the inner circle, some thermocouples become hotter than others, but the reading remains unchanged because the sum of all thermocouples is measured.

[0049] Specifically, as shown in Figures 4a to 4h, the shape of the heat conduction plate 21 is not limited to circles, rectangles, and regular polygons, but may be other shapes not shown, and may be in a regular or irregular pattern. The thermopile 22 forms a closed curve around the light incident region 25, or the thermopile 22 and the adiabatic edge 23 are enclosed by a closed curve. The pology pattern of the closed curve enclosed by the thermopile 22 (or thermopile 22 and adiabatic edge 23) installed on the heat conduction plate 21 does not necessarily correspond to the shape of the heat conduction plate 21. Also, the installation position of the thermopile 22 is not limited to the center of the heat conduction plate 21. If a portion of the side of the heat conduction plate 21 is installed as an adiabatic edge 23, the installation position of the thermopile 22 can be near the edge or corner.

[0050] In the embodiment shown in Figure 4a, the heat conduction plate 21 is circular in shape, and the thermopile 22 is an annular thermopile 220 formed by connecting multiple thermocouples in series. The annular thermopile 220 is distributed around the center of the heat conduction plate 21 to form a closed curve. As shown in Figure 4a, the light incidence region 25 is shown as a gray region, the annular thermopile 220 is arranged in a circle around the light incidence region 25, and the heat dissipation region 24 is shown as indicated by the letter c outside the annular thermopile 220. In the light incidence region 25, the direction of heat diffusion is indicated by a black arrow, and all heat absorbed by the light incidence region 25 is dissipated to the outside through the annular thermopile 220.

[0051] In the embodiment shown in Figure 4b, the heat conduction plate 21 is circular in shape, and the thermopile 22 is a box-shaped thermopile 221 formed by connecting multiple thermocouples in series. The box-shaped thermopile 221 is distributed around the center of the heat conduction plate 21 to form a closed curve. As shown in Figure 4b, the light incidence region 25, which is limited by the box-shaped thermopile 221, is shown as a gray region, and the box-shaped thermopile 221 is arranged in a box shape around the light incidence region 25. The heat dissipation region 24 is indicated by the letter c outside the box-shaped thermopile 220, and the direction of heat diffusion is indicated by a black arrow within the light incidence region 25. All heat absorbed by the light incidence region 25 is dissipated to the outside through the box-shaped thermopile 221.

[0052] In the embodiment shown in Figure 4c, the heat conduction plate 21 is rectangular in shape, and the thermopile 22 is a box-shaped thermopile 221 formed by connecting multiple thermocouples in series. The box-shaped thermopile 221 is distributed around the center of the heat conduction plate 21 to form a closed curve. As shown in Figure 4c, the light incidence region 25, which is limited by the box-shaped thermopile 221, is shown in gray, and the box-shaped thermopile 221 is arranged in a box shape around the light incidence region 25. The heat dissipation region 24 is indicated by the letter c outside the box-shaped thermopile 221, and the direction of heat diffusion is indicated by the black arrow inside the light incidence region 25. All heat absorbed by the light incidence region 25 is dissipated to the outside through the box-shaped thermopile 221.

[0053] In the embodiment shown in Figure 4d, the heat conduction plate 21 is hexagonal in shape, and the thermopile 22 is a triangular thermopile 222 formed by connecting multiple thermocouples in series. The triangular thermopile 222 is distributed around the center of the heat conduction plate 21 so as to form a closed curve. As shown in Figure 4d, the light incidence region 25, which is limited by the triangular thermopile 222, is shown as a gray area. The triangular thermopile 222 is arranged triangularly around the light incidence region 25, and the heat dissipation region 24 is indicated by the sign c outside the triangular thermopile 222. The direction of heat diffusion is indicated by a black arrow within the incidence region 25. All heat absorbed by the light incidence region 25 is dissipated to the outside through the triangular thermopile 222.

[0054] In the embodiment shown in Figures 4e to 4h, the heat conduction plate 21 is rectangular in shape, and an insulating edge 23 is installed on one or two sides of the heat conduction plate 21. The thermopile 22 is positioned in the area surrounding the light incident region 25 that is not enclosed by the insulating edge 23, and both the insulating edge 23 and the thermopile 22 are enclosed by a closed curve. Since the insulating edge 23 is installed close to the side or corner, the closed region enclosed by the thermopile 22 and the insulating edge 23 is also installed close to the side or corner, and the amount of heat absorbed from the light incident region 25 is simply dissipated outward from the direction in which the thermopile 22 is located.

[0055] In Figure 4e, the insulating edge 23 is installed on the upper side of the heat conduction plate 21 and occupies the central part of the upper side. The U-shaped thermopile 223 and the insulating edge 23 are enclosed in a box-shaped closed structure, and the inside of this structure is the light incidence region 25. The amount of heat absorbed by the light incidence region 25 is dissipated from the U-shaped thermopiles 223 installed on the left, lower, and right sides to the heat dissipation region 24 located outside the U-shaped thermopiles 223.

[0056] In Figure 4f, the insulating edge 23 is installed simultaneously on the left, upper, and lower edges of the heat conduction plate 21, occupying the left half of the upper and lower edges. The linear thermopile 224 is installed slightly to the right of the heat conduction plate 21, thereby dividing the heat conduction plate 21 into a light incidence region 25 located on the left and a heat dissipation region 24 located on the right. The amount of heat absorbed by the light incidence region 25 is dissipated from the linear thermopile 224 to the heat dissipation region 24 on the right.

[0057] In Figure 4g, the insulating edge 23 is installed simultaneously on the left and upper sides of the heat conduction plate 21, occupying the left portion of the left side and the upper half of the upper side. The folded-line thermopile 225 and the insulating edge 23 are enclosed in a box-shaped closed form, the interior of which is the light incidence region 25, and the light incidence region 25 is located near the upper left corner of the heat conduction plate 21. The amount of heat absorbed by the light incidence region 25 is dissipated from the folded-line thermopile 225 to the heat dissipation region 24 outside (specifically the lower and right sides of the folded-line thermopile 225).

[0058] In Figure 4h, the insulating edge 23 is installed simultaneously midway between the upper and lower edges of the heat conduction plate 21. The thermopile 226 includes two linear thermopiles 226a and 226b. The left thermopile 226a and the right thermopile 226b are installed on either side of the insulating edge 23, and one end (the lower end in the figure) of the left thermopile 226a and the right thermopile 226b are connected together by lead wires. The other ends (the upper ends in the figure) of the left thermopile 226a and the right thermopile 226b are led out as output terminals 22C. In this embodiment, the left region of the left thermopile 226a and the right region of the right thermopile 226b are heat dissipation regions 24. Therefore, the amount of heat absorbed by the light incidence region 25 passes through the left thermopile 226a and the right thermopile 226b and is dissipated to the heat dissipation regions 24 located on both sides of the conductive plate 21.

[0059] The thermopile 22, which is installed on the surface of the black silicon carbide ceramics 21, can be selected from different thermocouple combinations such as bismuth-silver, nickel-chromium-nickel-silicon, copper-constantan, and platinum-rhodium, depending on the application, including the application temperature, measurement accuracy, and operating environment.

[0060] Furthermore, as shown in Figure 5, the present invention further provides a pyroelectric photoelectric power meter (or pyroelectric photoenergy meter). This pyroelectric photoelectric power meter / pyroelectric photoenergy meter mainly comprises the pyroelectric photodetector and voltmeter 8 described above, and may further comprise other well-known compatible components. Of these, the output terminal 22C of the pyroelectric photodetector is connected to the voltmeter 8. The voltmeter 8 is used to measure a voltage value that represents a predetermined percentage of the actual power of the laser light awaiting measurement, output by the pyroelectric photodetector. The voltmeter 8 can be implemented using a digital multimeter, which can display the voltage value that represents a predetermined percentage of the actual power of the laser light awaiting measurement, output by the pyroelectric photodetector. The actual power of the laser light awaiting measurement can be inversely estimated based on the voltage value that represents a predetermined percentage of the actual power of the laser light awaiting measurement.

[0061] For example, if the incident light 10 is a laser that lasts for a long time, the amount of heat generated by the incident light 10 can stably maintain the temperature difference detected by the thermopile 22 installed on the surface of the heat conduction plate 21 for a long time. Accordingly, the curve of the output voltage of the thermopile maintains a constant peak value for a long time, and the pyroelectric photodetector can obtain the optical power of the incident light 10 by measuring the constant voltage generated by the thermopile 22 within a certain period of time. If the incident light 10 is an optical pulse with a short duration, the amount of heat generated by the optical pulse may cause the temperature difference detected by the thermopile 22 installed on the surface of the heat conduction plate 21 to fluctuate rapidly. Accordingly, the curve of the output voltage of the thermopile 22 fluctuates in a relatively short time, and the energy of the optical pulse can be obtained by integrating the voltage output by the thermopile 22 within a short time, thereby enabling the measurement of the optical pulse's energy.

[0062] It should be noted that the optical signals measured by the photodetector / optical power meter / optical energy meter of the present invention are mainly lasers, but may also include various types of optical signals such as ultraviolet light, infrared light, and X-rays, and may even include fluorescence emitted from weak light sources.

[0063] The structure of another pyroelectric photodetector provided by the present invention will be described below with reference to Figure 6.

[0064] Referring to Figure 6, the pyroelectric photodetector provided by an embodiment of the present invention comprises a heat conduction plate 301 made of silicon carbide ceramics, and further comprises a conductive metal layer 302 and a heat dissipation ceramic plate 303 connected in series. The entire heat conduction plate 301 is used as a light absorber. One surface of the heat conduction plate 301 is a light-absorbing surface (the top surface as shown in Figure 6), and incident light 10 is irradiated onto this surface, causing the heat conduction plate 301 to absorb heat. The conductive metal layer 302 connected in series is placed on the other surface of the heat conduction plate 301 (the bottom surface as shown in Figure 6), and the heat dissipation ceramic plate 303 is placed on one surface of the conductive metal layer 302 connected in series, away from the heat conduction plate 301. The heat conduction plate 301, the conductive metal layer 302 connected in series, and the heat dissipation ceramic plate 303 constitute a three-layer structure.

[0065] As shown in Figure 6, the thermal conductive plate 301 is manufactured from black silicon carbide ceramics, which simultaneously serve as both a thermal conductive plate and a light absorber, replacing the three-layer structure (aluminum alloy substrate, dark-colored light-absorbing coating layer, and insulating layer) in conventional pyroelectric photodetectors. By directly combining the black silicon carbide ceramics with conductive metal layers connected in series, a vertical pyroelectric photodetector is constructed, thereby simplifying the structure of the pyroelectric photodetector. At the same time, the high thermal conductivity, low thermal expansion coefficient, high heat resistance, and high laser damage threshold of the black silicon carbide ceramics, along with the fact that the light-absorbing surface can be cleaned using polishing methods, reduce the failure rate of the pyroelectric photodetector and significantly extend its service life. The manufacturing process of black silicon carbide ceramics and the beneficial effects it provides have been described in detail above and will not be repeated here.

[0066] The series-connected conductive metal layers 302 include a group of thermocouples consisting of multiple series-connected thermocouples 320. The first end 321 of the thermocouple group is the positive electrode, and the second end 322 of the thermocouple group is the negative electrode. The thermocouple group includes multiple semiconductor groups and multiple copper electrode sheets, and the semiconductor groups include N-type semiconductors and P-type semiconductors. The multiple semiconductor groups are sequentially connected in series via multiple copper electrode sheets, with the copper electrode sheets at both ends forming the positive and negative electrodes. In this embodiment, the thermocouple group uses pairs of common thermocouple materials such as pure copper-constantan or nickel-chromium-nickel silicon, or P-type and N-type bismuth telluride semiconductor type thermocouple materials.

[0067] The heat-dissipating ceramic plate 303 can be selected from various insulating and thermally conductive ceramics such as alumina, aluminum nitride, silicon carbide, and silicon nitride, and black silicon carbide ceramics can also be selected. By using a ceramic material with good thermal conductivity, the heat transfer effect between the heat-conducting plate 301 and the heat-dissipating ceramic plate 303 is guaranteed. Thus, an integrated light-thermal-electrical conversion effect is achieved.

[0068] A heat sink is provided on one surface of the heat-dissipating ceramic plate 303 that is away from the series-connected conductive metal layer 302 to dissipate heat. Preferably, the surface of the heat-dissipating ceramic plate 303 that is away from the series-connected conductive metal layer 302 is metallized to facilitate soldering to an external heat sink in order to dissipate heat.

[0069] A heat sink (not shown) is installed on the side of the heat dissipation ceramic plate 303 away from the conductive metal layer 302 connected in series, and is used to absorb the heat conducted from the heat conduction plate 301 to the heat dissipation ceramic plate 303, thereby rapidly cooling the heat dissipation ceramic plate 303.

[0070] In actual use, the pyroelectric photodetector absorbs incident light 10 using the heat conductive plate 301 and converts it into heat. This heat is then conducted to the series-connected conductive metal layer 302, and the heat is dissipated by the heat-dissipating ceramic plate 303. During this heat conduction process, an induced voltage (i.e., output voltage) is generated across the series-connected conductive metal layer 302 due to the Seebeck effect. Once stable heat conduction is achieved, the induced voltage across the series-connected conductive metal layer 302 is approximately proportional to the incident light power.

[0071] Compared to conventional planar diffuse pyroelectric photodetectors, this vertical pyroelectric photodetector offers faster response times and can withstand higher incident light power. By using thermocouples with high thermal conductivity and increasing the ratio of the thermocouple's cross-section to the silicon carbide ceramic area of ​​the incident surface, the thermal conductivity of the pyroelectric photodetector can be significantly increased, further improving the incident light power. The high power and fast response characteristics of this pyroelectric photodetector make it particularly suitable for real-time power measurement and variability monitoring of fiber lasers at current kilowatt, 10,000 watt, and even higher power levels. Using semiconductor thermocouple materials with high ZT values ​​(Thermoelectric Figure of Merit), this pyroelectric photodetector can be used as an excellent photoelectric conversion device for applications such as solar power generation.

[0072] The present invention further provides a method for manufacturing a pyroelectric photodetector shown in Figure 6. The manufacturing method includes the following steps. Step S1: To meet the roughness requirements, the light incident surface of the black silicon carbide ceramics is ground and polished. Step S2: Sputtering, electroplating, and etching one surface of the black silicon carbide ceramic opposite to the light incident surface forms a thermocouple pad and a series link circuit on the first side. Step S3: Sputter, electroplat, and etch one surface of the heat dissipation ceramic plate to form a thermocouple pad and a corresponding series link circuit on the second side. Step S4: Process the two types of matched thermocouples into particles of the same height. Step S5: Apply solder to the surfaces of both thermocouples, neatly assemble and arrange the black silicon carbide ceramics, heat dissipation ceramic sheet and thermocouples, and place them gently on the heating plate. Step S6: Use a heating plate to heat and reflow solder the assembled and arranged ceramics, solder, and thermocouple group. Step S7: Solder the two output terminals of the thermocouple group to the lead wires using the spot soldering method.

[0073] Specifically, in step S1, the light incident surface of the black silicon carbide ceramic is ground and polished to achieve a uniform roughness (Ra=0.8 is proposed, mirror polishing should be avoided) and ensure uniformity of light absorption.

[0074] Step S2 includes the following substeps: Step S21: Magnetron sputtering is performed on the soldering surface of the black silicon carbide ceramic (i.e., one surface opposite to the light incident surface) to plate Ti-Cu or Cr-Cu. The Ti layer or Cr layer is used to enhance the bonding strength of the metal layer, and the overall thickness of the magnetron sputtering is generally 2 μm or less. Step S22: The sputtered black silicon carbide ceramics can be electroplated with Cu in water to thicken the copper layer to 10-50 μm, and then selectively plated with a gold layer (usually less than 1 μm thick) on the surface to facilitate subsequent soldering. Step S23: A mask plate is manufactured and the metal layer of electroplated black silicon carbide ceramics is etched in water to form a link circuit connected in series with the thermocouple pad on one side (i.e., the first side).

[0075] In step S3, by sputtering, electroplating, and etching one surface of the heat dissipation ceramic plate using the same method as in steps S21 to S23, the pad on the other side (i.e., the second side) and the corresponding series-connected link circuit can be formed.

[0076] The heat dissipation ceramic plate can be selected from various insulating and thermally conductive ceramics such as alumina, aluminum nitride, silicon carbide, and silicon nitride. For example, the heat dissipation ceramic plate can be made from alumina ceramics, or the pads and circuits can be directly manufactured using the DBC process.

[0077] Additionally, metallization can be used on other sides of the heat-dissipating ceramic plate to support soldered heat dissipation between it and the heat sink.

[0078] In step S4, the two types of matched thermocouples are processed into particles of the same height (using different shapes such as cubes, cuboids, or cylinders). Depending on the material, pickling or other cleaning processes are performed to remove surface dirt and oxide layers and to ensure cleanliness of the upper and lower soldering surfaces.

[0079] In step S5, solder paste is applied between the pads and circuits of the ceramic sheets on both sides, solder evaporation or solder sheets may be used, or a certain liquid flux may be applied, and the upper and lower ceramics (including black silicon carbide ceramics and heat dissipation ceramic plates) and thermocouples are neatly assembled and arranged and placed peacefully on the heating plate.

[0080] When using gold-tin solder sheets of models such as Au80 / Sn20 or Au85 / Sn15, it is suggested to gold-plate the pads on the ceramic surface. Thus, after the gold-tin solder and the electroplated gold layer melt, the gold composition ratio in the solder increases, and the melting point for remelting rises.

[0081] In step S6, a heating plate is used to heat and reflow solder the assembled and arranged ceramics, solder, and thermocouple. Different temperature curves and gas environments, such as nitrogen gas or a vacuum environment, can be set for different solders. Applying constant pressure to the ceramics during the soldering process can improve solder quality and reliability.

[0082] In step S7, the two output terminals of the thermocouple group are soldered to the lead wires using the spot soldering method.

[0083] Finally, to clean the soldered thermoelectric photodetector, flux residue and other organic contaminants generated by soldering can be removed by immersion and rinsing with trichloroethylene or trichloromethane.

[0084] If moisture protection is required for the thermocouple, after step S7 is completed, the gap between the two ceramics (black silicon carbide ceramics and thermal conductive ceramic plate) can be edge-sealed with a material such as silica gel or epoxy resin to insulate against water vapor.

[0085] As described above, the thermoelectric photodetector provided by the embodiment of the present invention uses a heat conductive plate made of silicon carbide ceramics as the light absorber, so that even if damage occurs to the surface of the light absorber, the laser absorption rate is not affected. The present invention overcomes the problem in conventional thermoelectric photodetectors where strong light reflection occurs when the metal heat conductive base is exposed to the irradiated laser, causing the detector to shift. At the same time, because silicon carbide ceramics are insulators, by directly installing a thermopile or a series-connected conductive metal layer on the surface of the light absorber, it is possible to prevent the thermopile or the series-connected conductive metal layer from falling off due to thermal expansion of the heat conductive plate. Furthermore, by directly contacting the thermopile or the series-connected conductive metal layer and the heat conductive plate, reliability is increased, heat conduction is faster, and the response is more sensitive.

[0086] Black silicon carbide ceramics have high thermal conductivity, a low coefficient of thermal expansion, high heat resistance, and a high laser damage threshold, which has the advantage of allowing the light-absorbing surface to be cleaned by polishing. Therefore, heat can be dissipated rapidly, and the detachment of the thermopile due to thermal expansion of the heat conduction plate can be prevented. In addition, damage to the light-absorbing surface of the heat conduction plate can be reduced, the failure rate of the pyroelectric photodetector can be reduced, and the service life of the pyroelectric photodetector can be significantly extended. Even if minor damage occurs to the light-absorbing surface of the black silicon carbide ceramics during use, the light spot marks on the surface of the black silicon carbide ceramics can be easily cleaned by simple cleaning, such as polishing with diamond polishing paste. The pyroelectric photodetector provided by the embodiment of the present invention has a simple structure, low cost, reliable performance, and long service life, and is particularly suitable for power measurement of lasers or other light sources or energy measurement of light pulses, thus having great economic value.

[0087] The pyroelectric photodetector based on silicon carbide ceramics provided by the present invention has been described in detail above. To those skilled in the art, any obvious modification made thereto without departing from the substantial spirit of the invention will constitute infringement of the patent rights of the present invention and will result in corresponding legal liability.

Claims

1. A thermoelectric photodetector, It is equipped with a heat conductive plate made of black silicon carbide ceramics, and the heat conductive plate functions as a light absorber as a whole. One surface of the heat conductive plate is a light-absorbing surface, The system further comprises thermopiles directly arranged on the light-absorbing surface or the other surface, A thermoelectric photodetector characterized in that the surface roughness Ra of the light-absorbing surface of the aforementioned silicon carbide ceramic is between 0.8 and 6.3 μm.

2. The thermoelectric photodetector according to claim 1, characterized in that the thermopile forms a closed curve around the light incidence region.

3. The thermoelectric photodetector according to claim 1, characterized in that the thermopile and the insulating edge together form a closed curve around the light incident region.

4. It further comprises multiple conductive metal layers and heat-dissipating ceramic plates connected in series, The thermoelectric photodetector according to claim 1, characterized in that one surface of the heat conduction plate is a light-absorbing surface, the plurality of series-connected conductive metal layers are installed on the other surface of the heat conduction plate, and a heat-dissipating ceramic plate is installed on one surface of the plurality of series-connected conductive metal layers away from the heat conduction plate.

5. The thermoelectric photodetector according to claim 4, characterized in that the plurality of series-connected conductive metal layers comprises a group of thermocouples composed of a plurality of series-connected thermocouples, the group of thermocouples comprises a plurality of semiconductor groups and a plurality of copper electrode sheets, the semiconductor groups comprise N-type semiconductors and P-type semiconductors, the plurality of semiconductor groups are sequentially connected in series via a plurality of copper electrode sheets, and the copper electrode sheets at both ends, the leading and trailing ends, form a positive electrode and a negative electrode.

6. The thermoelectric photodetector according to claim 5, characterized in that one surface of the heat-dissipating ceramic plate, away from a plurality of conductive metal layers connected in series, is metallized.

7. The thermoelectric photodetector according to claim 5, characterized in that a heat sink is installed on one surface of the heat-dissipating ceramic plate that is away from a plurality of conductive metal layers connected in series.

8. The thermoelectric photodetector according to claim 1, characterized in that the light-absorbing surface is cleaned by a polishing method.

9. The thermoelectric photodetector according to claim 1, characterized in that the silicon black carbide ceramic is formed by sintering silicon black carbide powder.

10. The thermoelectric photodetector according to claim 9, characterized in that the silicon black carbide ceramic is formed by sintering silicon black carbide powder in a pressurized environment.

11. The density of the aforementioned black silicon carbide ceramics is 2.6 to 3.2 g / cm³. ３ A thermoelectric photodetector according to claim 1, characterized in that it is between [a certain range].

12. The laser damage threshold for the aforementioned silicon carbide ceramics is 3 GW / cm² at narrow pulse high peak power. ２ Beyond that, with broad pulses and high energies, at least 200–500 J / cm² ２ The thermoelectric photodetector according to claim 1, characterized in that it is the same as described above.

13. The thermoelectric photodetector according to claim 1, characterized in that the black silicon carbide ceramics include, but are not limited to, silicon carbide ceramics of dark blue, dark gray, and charcoal gray colors.

14. A thermoelectric type optical power meter, A thermoelectric photoelectric power meter comprising a voltmeter and a thermoelectric photodetector as described in claim 1, wherein the voltmeter is connected to the output terminal of the thermoelectric photodetector.

15. A thermoelectric type optical energy meter, A thermoelectric photometer comprising a voltmeter and a thermoelectric photodetector as described in claim 1, wherein the voltmeter is connected to the output terminal of the thermoelectric photodetector.

16. A method for manufacturing a thermoelectric photodetector according to claim 4, wherein the manufacturing method is: Step S1 involves grinding and polishing the light incident surface of the black silicon carbide ceramic in order to meet the roughness requirements, Step S2 involves sputtering, electroplating, and etching one surface of a black silicon carbide ceramic opposite to the light incident surface to form a thermocouple pad and a series link circuit on the first side. Step S3 involves sputtering, electroplating, and etching one surface of a heat dissipation ceramic plate to form a thermocouple pad and a corresponding series link circuit on the second side. Step S4 involves processing two types of matched thermocouples into particles of the same height, Step S5 involves applying solder to the surfaces of both thermocouples, arranging the black silicon carbide ceramics, heat dissipation ceramic sheet, and thermocouples in an orderly manner, and then placing them peacefully on the heating plate. Step S6 involves using a heating plate to heat the assembled and arranged ceramics, solder, and thermocouple group and reflow solder them. A manufacturing method characterized by including step S7 of soldering the two output terminals of a thermocouple group to lead wires using a spot soldering method.

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