A laser beam uniformity testing device for a laser

Abstract

The present invention discloses a laser uniformity testing device for a laser, belonging to the technical field of laser testing. It is characterized in that it includes a laser battery array system and a laser battery testing system; the laser battery array system includes L laser batteries; each laser battery is provided with independent positive and negative lead terminals; L is a natural number greater than 1; the laser battery testing system includes L sampling resistors, a voltage acquisition circuit for measuring the voltage across each sampling resistor, and a signal receiving terminal for receiving the output signals of each voltage acquisition circuit; wherein: the positive lead terminals of the L laser batteries are connected; the negative lead terminal of each laser battery is connected to a sampling resistor to form a sampling loop; the output terminal of the voltage acquisition circuit performs data interaction with the signal receiving terminal. The present invention can quantitatively detect the uniformity of laser by using multiple laser batteries.

Description

Technical Field

[0001] The present invention belongs to the technical field of laser testing, and particularly relates to a laser uniformity testing device for a laser. Background Art

[0002] Laser has the characteristics of good monochromaticity, strong directivity, and high brightness. Laser technology plays a crucial role in industries such as military, national defense, industry, and medical treatment. Therefore, the measurement and analysis of laser performance become increasingly important.

[0003] The uniformity of the light beam is a very important characteristic parameter of the laser. Especially for large-aperture lasers, there is a large difference in the light intensity of each point within the laser aperture, which greatly affects the laser quality. Therefore, it is necessary to adjust the laser parameters through real-time feedback of laser uniformity data to ensure the laser uniformity. Since large-aperture high-power lasers cannot be turned on and off immediately, the laser needs to continuously irradiate the testing device during the adjustment process.

[0004] A solar cell converts light into electrical energy through photoelectric conversion. Similarly, a laser cell also converts laser with a specific wavelength into electrical energy through photoelectric conversion, but it only absorbs a specific spectrum (designated laser wavelength). Due to the efficiency of the cell, the laser cannot be completely converted into electrical energy, and most of the energy is converted into heat, which will affect the solar cell. Since the laser cell is a semiconductor device, the higher the heat, the lower the efficiency, which is reflected in the increase of the short-circuit current and the decrease of the open-circuit voltage, as Figure 1 shown. Therefore, even under the irradiation of the same laser energy, the cell efficiency measured at different cell temperatures is different. Therefore, when using a laser cell to measure the uniformity of a large-aperture laser, it is necessary to control or compensate for the cell heat. Summary of the Invention

[0005] In view of the above technical defects, the present invention provides a laser uniformity testing device for a laser, which quantitatively detects the laser uniformity by using multiple laser cells.

[0006] To achieve the above technical objectives, the present invention is realized through the following technical solutions:

[0007] A laser uniformity testing device for a laser includes a laser cell array system and a laser cell testing system; the laser cell array system includes L laser cells; each laser cell is provided with independent positive and negative lead terminals; L is a natural number greater than 1; the laser cell testing system includes L sampling resistors, a voltage acquisition circuit for measuring the voltage across each sampling resistor, and a signal receiving terminal for receiving the output signals of each voltage acquisition circuit; wherein: the positive lead terminals of the L laser cells are connected; the negative lead terminal of each laser cell is connected to a sampling resistor to form a sampling loop; the output terminal of the voltage acquisition circuit exchanges data with the signal receiving terminal.

[0008] Preferably, it further includes a temperature control system, which includes a water-cooled platform, a water-cooled radiator, and a large-flow water-cooled pump station; a water circulation pipeline is arranged inside the water-cooled platform, and the water-cooled radiator and the large-flow water-cooled pump station are connected through the water circulation pipeline.

[0009] Preferably, the water-cooled platform is made of conductive metal material, and the positive lead terminal of the L-chip laser battery is welded or bonded to the water-cooled platform.

[0010] Preferably, the water-cooled platform is an aluminum platform, a copper platform or other metal platforms.

[0011] Preferably, it further includes a temperature compensation system.

[0012] Preferably, the temperature compensation system includes a matrix infrared thermal imager.

[0013] Preferably, the voltage acquisition circuit includes a synchronous sampling analog-to-digital converter.

[0014] The advantages and technical effects of the present invention are:

[0015] In the present invention, multiple laser batteries are arranged on the optical path of the laser, and by detecting the output voltage of each laser battery, the uniformity of the laser can be quantitatively detected and evaluated.

[0016] The present invention utilizes the temperature control system to well ensure the stability of the laser battery during operation and guarantee the accuracy of the test results.

[0017] The present invention utilizes the temperature compensation system to facilitate the establishment of a mapping relationship between the temperature and efficiency of the laser battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a graph of current and voltage of the laser battery at different temperatures;

[0019] Figure 2 is a schematic structural diagram of a preferred embodiment of the present invention;

[0020] Figure 3 is a structural diagram of the battery array in a preferred embodiment of the present invention;

[0021] Figure 4 is a structural diagram of the temperature compensation system in a preferred embodiment of the present invention;

[0022] Figure 5 is a circuit diagram of the voltage acquisition circuit in a preferred embodiment of the present invention;

[0023] Figure 6 is a schematic diagram of signal sampling in a preferred embodiment of the present invention;

[0024] Figure 7 It is the structural diagram of the temperature control system in the preferred embodiment of the present invention. Detailed implementation manners

[0025] In order to make the above objects, the designed control system and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below in conjunction with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0026] Please refer to Figures 1 to 7 , a laser uniformity test device for a laser, including a laser cell array system 1, a temperature control system, a temperature compensation system, and a laser cell test system 2; wherein:

[0027] The laser cell array system includes L laser cells; each laser cell is provided with independent positive and negative lead terminals; L is a natural number greater than 1; the laser cell test system includes L sampling resistors, a voltage acquisition circuit for measuring the voltage across each sampling resistor, and a signal receiving terminal for receiving the output signals of each voltage acquisition circuit; wherein: the positive lead terminals of the L laser cells are connected; the negative lead terminal of each laser cell is connected to a sampling resistor to form a sampling loop; the output terminal of the voltage acquisition circuit exchanges data with the signal receiving terminal.

[0028] The temperature control system includes a water-cooled platform 5, a water-cooled radiator 8, and a large-flow water-cooled pump station 7; a water circulation pipeline 6 is arranged in the water-cooled platform, and the water-cooled radiator and the large-flow water-cooled pump station are connected through the water circulation pipeline.

[0029] The water-cooled platform is made of a conductive metal material, and the positive lead terminals of the L laser cells are welded or bonded to the water-cooled platform.

[0030] The voltage acquisition circuit includes a synchronous sampling analog-to-digital converter.

[0031] The technical solution of the present invention mainly includes four systems, namely: a laser cell array system, a temperature control system, a temperature compensation system, and a laser cell efficiency electrical measurement system; wherein:

[0032] Laser battery array system: It converts light energy into electrical energy. According to the conversion efficiency, the electrical output of each battery is sampled through an independent channel. Taking a laser aperture of 0.2 m as an example, due to laser divergence, the laser intensity at each point within a measurement range of 1 m needs to be measured. Therefore, laser batteries can be evenly arranged within a 1 m circular area, and the positive and negative electrodes of each laser battery are led out separately for independent measurement of the performance of each battery. This range can be divided into many small grids of 5 mm × 5 cm, and one solar cell is arranged in each small grid. (The number of batteries can be adjusted according to the number of evenly distributed laser test points. If more measurement points are required, the grid size can be reduced, or multiple batteries can be arranged in one grid). For example, Figure 3 As shown in the battery arrangement method, 2 batteries are arranged in each 5 × 5 cm grid within the central area of 0.2 m, and 1 battery is arranged in each grid of the same size in the outer area. The laser battery is divided into positive and negative poles. The positive pole of the battery is on the back of the battery, and the positive pole is Ag covering the back of the battery. Therefore, all the batteries can be electrically connected at the back through a conductive substrate, achieving the design of a common anode for all batteries; the negative pole of each battery is independently led out through a wire and led to the electrical measurement system.

[0033] Temperature control system: Since the battery output efficiency is affected by temperature, a temperature control system is required to ensure that the temperature of the battery is uniform under laser irradiation, including a water-cooled platform, a water-cooled radiator, a large-flow water-cooled pump station, etc.; due to the existence of battery conversion efficiency (about 30% - 50% is converted into electrical energy), most of the laser energy becomes heat, and it often takes more than 10 minutes to adjust the laser. The accumulation of heat is sufficient to burn out the battery. This temperature control system includes a large water-cooled platform (which can be designed with a diameter of 1 m as in the above example), and typical materials are aluminum or copper. To better dissipate heat, the back (positive pole) of each battery is soldered to the water-cooled platform (conductive adhesive bonding can also be selected, but the heat conduction ability of conductive adhesive bonding is much lower than that of soldering). It includes a water chiller to cool the water in the water-cooled platform, (tap water can also be connected), but the water-cooled flow needs to be ensured.

[0034] Temperature compensation system: Even with water cooling, the heat will be higher in areas with high laser intensity. Therefore, a solar cell temperature compensation system is designed to bring the batteries with high and low temperatures to the same starting line through an algorithm; the uniformity of the laser at each point is different, so the heat on each battery is also different. Therefore, it is necessary to compensate for the influence of the heat of each battery on the battery performance. A planar array infrared thermal imager 3 (CCD) is used to monitor the temperature of each laser battery. When the electrical control system needs temperature data, it notifies the infrared thermal imager to take a picture and uploads the surface temperature data to the electrical control system. The electrical control system 4 extracts the heat of each battery, as Figure 4 shown. Before forming the system, a mapping relationship between the battery temperature and efficiency is established, that is, the efficiency of the battery is measured at different temperatures, and this curve is input into the machine to convert the power generation performance of the battery into the performance at 25°C.

[0035] Example: For the two cells A and B in the above-mentioned area array, the temperature detected by cell A is 60°C, and the temperature detected by cell B is 95°C. If the fixed-point currents of both cells A and B are 220 mA (in the flat characteristic section of the IV curve), through the mapping relationship, it can be inversely calculated that the fixed-point current of cell A should be 210 mA (converted at 25°C), and the fixed-point current of cell B should be 200 mA (converted at 25°C). The electronic control system calculates the actual efficiency of the battery (nuclear power generation) based on this.

[0036] Laser battery test system: Briefly called the electrical measurement system, the laser battery outputs independently. According to the preliminary design, about 300 cells are required in total. This test system can complete the synchronous sampling of 300 cells and form a data packet to report to the host computer.

[0037] (1) Interaction with the laser battery array system: The common anode of each cell leads out of the system, and the negative lead of each cell is introduced into each measurement port. A sampling resistor with the same resistance value is connected to each port, and the resistor forms a loop with the cell. The electronic control system measures the voltage across each sampling resistor to reflect the state of each cell, as Figure 5 shown. In the example, a total of 304 sampling resistors are connected to the above-mentioned array, and the voltage across the measuring resistor is measured.

[0038] (2) Interaction with the temperature control system: The water cooling supply can be turned on and off.

[0039] (3) Interaction with the temperature compensation system: Notify the CCD to take a picture when acquisition is needed, obtain the temperature data of the area array, calculate the temperature of each cell, and perform a compensation algorithm through the mapping between the temperature and performance of the above-mentioned cells to bring the test data of each cell to the same temperature starting line.

[0040] In addition to the interaction with other systems, the main body of this system consists of a synchronous sampling analog-to-digital converter (ADC). Obviously, due to the instantaneous changes of the laser, it is best to complete data sampling within the ms level. In the above example, 304-channel ADC synchronous sampling needs to be performed on it. Since synchronous sampling chips usually support a maximum of 8 channels, for example, the 24-bit synchronous sampling chip AD7768 of Analog Devices only supports 8 channels. Therefore, 38 AD7768 chips are designed to complete the system, as Figure 6 shown. The microcontroller chip (MCU) performs synchronous sampling on each ADC from the preparation stage, and establishes a column vector for the data at the same moment. When the host computer needs the MCU to obtain data, it sends a command to let the MCU transfer this column vector to the host computer, so as to obtain the performance of all the above-mentioned cells. The host computer inversely calculates the laser energy at each point through the above temperature compensation algorithm, and the overall normalization to obtain the surface energy matrix is the laser uniformity of the spot.

[0041] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A laser beam uniformity testing device for a laser, characterized in that, It includes a laser battery array system and a laser battery test system; the laser battery array system includes L laser batteries; each laser battery is provided with independent positive and negative lead terminals; L is a natural number greater than 1; the laser battery test system includes L sampling resistors, a voltage acquisition circuit for measuring the voltage across each sampling resistor, and a signal receiving terminal for receiving the output signals of each voltage acquisition circuit; wherein: the positive lead terminals of the L laser batteries are connected; the negative lead terminal of each laser battery is connected to a sampling resistor to form a sampling loop; the output terminal of the voltage acquisition circuit exchanges data with the signal receiving terminal.

2. The laser beam uniformity testing device for a laser according to claim 1, characterized in that: It further includes a temperature control system, and the temperature control system includes a water-cooled platform, a water-cooled radiator, and a large-flow water-cooled pump station; a water circulation pipeline is arranged in the water-cooled platform, and the water-cooled radiator and the large-flow water-cooled pump station are connected through the water circulation pipeline.

3. The laser beam uniformity testing device for a laser according to claim 2, wherein: The water-cooled platform is made of conductive metal material, and the positive lead terminals of the L laser batteries are welded or adhered to the water-cooled platform.

4. The laser beam uniformity testing device for a laser according to claim 3, characterized in that: The water-cooled platform is an aluminum platform or a copper platform.

5. The laser beam uniformity testing device for a laser according to claim 1, characterized in that: It further includes a temperature compensation system.

6. The laser beam uniformity testing device for a laser according to claim 5, characterized in that: The temperature compensation system includes a planar array infrared thermal imager.

7. The laser beam uniformity testing device for a laser according to claim 1, characterized in that: The voltage acquisition circuit includes a synchronous sampling analog-to-digital converter.

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