A rapid photo-current imaging test device and system thereof
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- ZOLIX INSTRUMENTS CO LTD
- Filing Date
- 2025-07-28
- Publication Date
- 2026-06-23
Smart Images
Figure CN224401488U_ABST
Abstract
Description
Technical Field
[0001] This application relates to solar cell testing technology, and more particularly to a fast photocurrent imaging testing device and system thereof. Background Technology
[0002] Photocurrent imaging of solar cells is a technique that uses optical methods to detect and analyze the performance of solar cells. This technique can accurately create two-dimensional images of defects in solar cells, such as dislocations, cracks, and short-circuit regions, which is of great significance for quality control and yield improvement in the solar cell manufacturing process.
[0003] The main principle of using solar cell photocurrent imaging to perform two-dimensional imaging of solar cell defects is as follows: A solar cell sample is irradiated with a laser of a specific wavelength, exciting a photocurrent within the sample. This photocurrent signal is then extracted via a probe to a current source meter and read out by software. During the scanning process, the laser spot is controlled to move across the sample surface, and the software records the current value corresponding to each spot position, simultaneously plotting a photocurrent image on the software to display the current distribution of the solar cell sample. By analyzing the photocurrent distribution, the minute internal structures and defects of the solar cell can be clearly distinguished, providing a basis for in-depth research on the performance and damage mechanisms of solar cells. This non-contact, precise measurement of solar cells is an important solar cell detection and analysis technology, playing an irreplaceable role in improving the quality and performance of solar cells.
[0004] The above photocurrent imaging testing technology, when using an electrically controlled displacement stage, achieves photocurrent imaging mapping by moving the position of the solar cell sample or the light source. However, it has the following drawbacks: First, the sample moves along with the motorized stage during movement, resulting in slow speed and long testing times. Second, the mapping resolution depends on the stage's movement resolution; the larger the stage area, the lower the resolution. Third, using an electrically controlled displacement stage requires a large testing area. For example, when constantly moving the sample, the actual testing area occupied is four times the test area.
[0005] Furthermore, existing technologies also employ photocurrent imaging testing using controlled galvanometers. However, this method has significant drawbacks. The galvanometer-controlled method only allows control of the laser spot. After moving the laser spot to a position to test the electrical signal of the solar cell sample at that location, the spot must be moved to a new position for further testing. Therefore, this method of using a galvanometer to control a moving laser spot to test the photoelectric signal at a corresponding location on the solar cell sample is slow in both movement and testing speeds, requires a long testing time, and thus has very low testing efficiency. Utility Model Content
[0006] In view of this, the main objective of this application is to provide a fast photocurrent imaging testing device and system, which aims to address the problems of slow movement speed and long time required when moving the sample under test using an electronically controlled moving stage during photocurrent testing, as well as to significantly reduce the footprint of the testing device and system.
[0007] To achieve the above objectives, this application adopts the following technical solution:
[0008] A rapid photocurrent imaging testing device includes a laser source 1 and a sample to be tested; characterized in that it further includes a beam expander 2, a galvanometer 3, a field lens 4, a data acquisition unit 6, a synchronization signal generator 7, and a controller 8; wherein:
[0009] The laser source 1, beam expander 2, galvanometer 3, field mirror 4, and sample under test are sequentially connected through a laser optical path; the controller 8 is bidirectionally electrically connected to the data acquisition unit 6 and the synchronization signal generator 7; the synchronization signal generator 7 is unidirectionally electrically connected to the galvanometer 3 and the data acquisition unit 6; the signal output terminal of the sample under test is electrically connected to the data acquisition unit 6.
[0010] The beam expander 2 is used to enlarge the diameter of the laser beam emitted by the laser source 1, so that the laser beam is focused by the field mirror 4 to obtain a smaller diameter spot.
[0011] The synchronization signal generator 7 is used to receive the control signal from the controller 8 to generate a synchronization signal for controlling the movement of the galvanometer 3 and for the data acquisition device 6 to perform data acquisition.
[0012] The galvanometer 3 is used to control the rotation angle of the reflector according to the synchronization signal, thereby adjusting the emission direction of the laser beam;
[0013] The field mirror 4 is used to focus the laser beam and couple it to obtain a laser spot with a smaller focal diameter;
[0014] Data acquisition unit 6 is used to collect photocurrent / photovoltage signals of the sample under test according to the synchronization signal.
[0015] Wherein: the laser source 1 is a laser that can emit one wavelength or / and multiple wavelengths.
[0016] The galvanometer 3 is an optical device that includes at least one single-axis / multi-axis reflector, or an optical device that uses a piezoelectric deflector.
[0017] The field mirror 4 is also used to ensure that the laser beams at different positions are focused at the same working distance.
[0018] The field lens 4 is at least one lens, or a group of lenses.
[0019] The sample to be tested is placed on the sample stage 5, and the output signal terminal of the sample to be tested is electrically connected to the signal acquisition terminal of the data acquisition device 6.
[0020] The synchronization signal generator 7 uses a synchronization circuit to send synchronization signals to the galvanometer 3 and the data acquisition unit 6, causing the galvanometer 3 to deflect and change the position of the laser spot on the sample under test. At the same time, the data acquisition unit 6 synchronously acquires current / voltage signals, and the laser spot does not need to stop during the test process.
[0021] The controller 8 is used to control the synchronous signal generator 7 to output a synchronous electrical signal that enables the movement of the laser spot of the galvanometer 3 and the data acquisition unit 6 to collect current / voltage signals synchronously.
[0022] A test system including the fast photocurrent imaging test device further includes an optical path switching device added between the laser source 1 and the beam expander 2, for switching between lasers of multiple wavelengths.
[0023] The rapid photocurrent imaging testing device and system of this invention have the following advantages compared with the prior art:
[0024] This invention expands the laser beam, then couples it to the sample stage after passing through a galvanometer and a field mirror. By adjusting the beam position using the galvanometer, photocurrent imaging testing is achieved even when the sample remains stationary. This allows for simultaneous triggering of galvanometer adjustment and sample signal acquisition, enabling synchronous testing of photoelectric signals during beam movement. Since beam movement does not require stopping to acquire signals during testing, this significantly improves the speed of photocurrent imaging. Furthermore, it solves the problems of slow movement speed, long testing time, and excessive footprint of the testing device and system when using an electrically controlled moving stage to move the sample. Attached Figure Description
[0025] Figure 1 This is a schematic diagram of the architecture of the fast photocurrent imaging test device according to an embodiment of the present invention;
[0026] Figure 2This is a schematic diagram illustrating the data status of 1000 points in a row at a sampling frequency of 5Hz, according to an embodiment of this utility model.
[0027] Figure 3 This is a schematic diagram illustrating the data status of 2000 points in a row, collected at a frequency of 5Hz, according to an embodiment of this utility model. Detailed Implementation
[0028] The technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.
[0029] The terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such use of data can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class and the number of objects is not limited; for example, a first object can be one or more. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.
[0030] Figure 1 This is a schematic diagram of the architecture of the fast photocurrent imaging test device according to an embodiment of the present invention.
[0031] like Figure 1 As shown, this rapid photocurrent imaging testing device mainly includes: a laser source 1, a beam expander 2, a galvanometer 3, a field lens 4, a sample stage 5, a data acquisition unit 6, a synchronization signal generator 7, and a controller 8. Among them:
[0032] The laser source 1, beam expander 2, galvanometer 3, field lens 4, and the solar cell sample under test (placed on the sample stage 5) are sequentially connected via a laser optical path. The controller 8 is bidirectionally electrically connected to the data acquisition unit 6 and the synchronization signal generator 7; the synchronization signal generator 7 is unidirectionally electrically connected to the galvanometer 3 and the data acquisition unit 6; the solar cell sample under test is placed on the sample stage 5, and the signal output terminal of the solar cell sample under test is electrically connected to the data acquisition unit 6.
[0033] The laser source 1 is a laser capable of emitting one wavelength or / and multiple wavelengths, and can emit laser light of different wavelengths according to the test requirements. For example, the laser wavelength can be 405nm, 532nm, 635nm, 808nm, etc., and one or more different laser wavelengths can be selected according to the test requirements.
[0034] The beam expander 2 is used to enlarge the diameter of the laser beam emitted by the laser source 1, which is beneficial for the laser beam to be focused by the field lens 4 to obtain a smaller diameter spot, thereby improving the resolution of photocurrent imaging.
[0035] The galvanometer 3 is used to control the emission direction of the laser beam by rotating its reflector.
[0036] Here, the galvanometer 3 can specifically be an optical device that includes at least one single-axis / multi-axis reflector; or it can be an optical device that uses a piezoelectric deflector.
[0037] Field lens 4 is used to focus the laser beam, couple it to obtain a laser spot with a smaller focal diameter, and enable the beam to be focused at a consistent working distance at different positions.
[0038] Here, the field lens 4 is at least one lens or a group of lenses.
[0039] The sample stage 5 is used to place the sample to be tested, such as a solar cell sample. The output signal terminal of the sample to be tested is electrically connected to the signal acquisition terminal of the data acquisition unit 6, and is used to transmit the output signal of the sample to the data acquisition unit 6.
[0040] Data acquisition unit 6 is used to collect photocurrent / photovoltage signals. It also receives a synchronization signal from synchronization signal generator 7 and, under the control of this synchronization signal, synchronously acquires photocurrent / photovoltage signals from the solar cell sample under test at a controllable speed, ensuring that the acquisition speed of the photocurrent / photovoltage signals is synchronized with the acquisition of photocurrent / photovoltage signals over the distance the light spot moves, controlled by galvanometer 3. Furthermore, it can provide real-time feedback to controller 8 on the acquisition status of the photocurrent / photovoltage signals of the sample under test, and controller 8 sends a control signal to the synchronization signal generator 7 to control the acquisition speed of the aforementioned signals, thereby achieving synchronous acquisition of photocurrent / photovoltage signals from different light spot movement distances on the sample under test.
[0041] The synchronization signal generator 7 is used to generate a synchronization signal to control the movement of the galvanometer 3 and data acquisition. The synchronization signal generator 7 can be a multi-channel arbitrary function signal generator, which controls the movement of the galvanometer 3 through its output voltage and simultaneously outputs a synchronization signal to the data acquisition unit 6 to initiate data acquisition of the sample under test.
[0042] Here, the data acquisition of the sample to be tested includes, but is not limited to, the magnitude of the photocurrent / photovoltage signal at the same position of the sample to be tested, as well as the magnitude of the photocurrent / photovoltage signal at different positions of the sample to be tested under the combined action of the galvanometer 3 and the field mirror 4.
[0043] The controller 8 is used to control the output of the synchronization signal generator 7 to move the light spot of the galvanometer 3 and collect the current signal, and then create a two-dimensional scanning optical signal image.
[0044] In the above embodiments of this invention, photocurrent imaging testing of the sample under test (including but not limited to optoelectronic devices such as solar cells) in a static state can be achieved through the galvanometer 4. However, it is not limited to photocurrent imaging testing; it can also perform spectral responsivity imaging testing, quantum efficiency imaging testing, and single-wavelength current-voltage characteristic testing, etc.
[0045] Preferably, in the above embodiments of the present invention, an optical path switching device can be added between the laser source 1 and the beam expander 2 to form a fast photocurrent imaging test system, which can realize the switching and selection between lasers of multiple wavelengths.
[0046] Furthermore, in the embodiments of this utility model, the synchronization signal generator 7 uses a synchronization circuit to send a synchronization signal to the galvanometer 3 and the data acquisition unit 6, causing the galvanometer 3 to deflect and change the position of the laser spot on the sample to be tested. At the same time, the data acquisition unit 6 synchronously acquires electrical signals such as current / voltage. The position of the spot does not need to be interrupted during the test, thus greatly reducing the time of photocurrent imaging test, as well as the test time of spectral responsivity imaging test, quantum efficiency imaging test, etc., and improving the test efficiency.
[0047] In a typical embodiment, the synchronization signal emitted by the synchronization signal generator 7 is a triangular wave signal (the voltage value is constantly changing, and for the galvanometer 3, the corresponding control action is to deflect the reflector at different angles). The galvanometer 3 can make the laser spot start to move, and a signal acquisition command is output synchronously. The data acquisition unit 6 then begins to acquire the electrical signal emitted by the sample under test.
[0048] When set to continuous electrical signal acquisition, different data acquisition time intervals correspond to different laser spot positions. The number of acquired values / data points can be calculated based on the set time intervals, corresponding to different laser spot positions. The total length swept by the laser spot (e.g., 100mm) divided by the number of acquired values / data points (e.g., 1000 points, reference) is calculated. Figure 2 ) or 2000 points (reference) Figure 3By scanning the rows, photocurrent signals at intervals of 0.05 mm can be obtained. After the row scan is completed, the image can be moved column by column to obtain a two-dimensional photocurrent / photovoltage signal imaging test pattern.
[0049] Assuming a mobile station is used for testing, testing one point takes approximately 0.5 seconds (s). If 1000 × 1000 points need to be tested (refer to...),... Figure 2 The required testing time would be 138 hours. However, using the galvanometer testing method of this invention, the fastest testing speed can reach 100Hz, meaning each row only needs 0.01s to test, and testing 1000 rows only takes 10s. Even if some samples have a slower response speed, the testing speed can still reach 5Hz, so the testing time required to complete 1000 rows is 200s.
[0050] As can be seen, by expanding the laser beam and coupling it to the sample stage after passing through a galvanometer and a field mirror, and then adjusting the beam position using the galvanometer, photocurrent imaging testing can be performed even when the sample is stationary. Furthermore, galvanometer adjustment and sample signal acquisition can be triggered synchronously, enabling simultaneous scanning and testing of photoelectric signals during beam movement. This eliminates the need to stop the beam movement during testing to collect signals, significantly improving the speed of photocurrent imaging scanning. It solves the problems of slow movement speed, long testing time, and excessive footprint of the testing device and system when using an electrically controlled moving stage to move the sample.
[0051] Based on the same inventive concept, this application also provides a test system including the fast photocurrent imaging test device, the test system further including an optical path switching device added between the laser source 1 and the beam expander 2, for switching between lasers of multiple wavelengths.
[0052] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this application.
Claims
1. A rapid photocurrent imaging testing device, comprising a laser source (1) and a sample to be tested; characterized in that, It also includes a beam expander (2), a galvanometer (3), a field lens (4), a data acquisition unit (6), a synchronization signal generator (7), and a controller (8); wherein: The laser source (1), beam expander (2), galvanometer (3), field mirror (4), and sample to be tested are connected sequentially through a laser optical path; the controller (8) is bidirectionally electrically connected to the data acquisition unit (6) and the synchronization signal generator (7); the synchronization signal generator (7) is unidirectionally electrically connected to the galvanometer (3) and the data acquisition unit (6); the signal output terminal of the sample to be tested is electrically connected to the data acquisition unit (6). The beam expander (2) is used to expand the diameter of the laser beam emitted by the laser source (1) so that the laser beam is focused by the field lens (4) to obtain a smaller diameter spot. The synchronization signal generator (7) is used to receive the control signal from the controller (8) to generate a synchronization signal for controlling the movement of the galvanometer (3) and for the data acquisition device (6) to perform data acquisition. The galvanometer (3) is used to control the rotation angle of the reflector according to the synchronization signal and adjust the emission direction of the laser beam; The field mirror (4) is used to focus the laser beam and couple it to obtain a laser spot with a smaller focal diameter; The data acquisition unit (6) is used to collect photocurrent / photovoltage signals of the sample under test according to the synchronization signal.
2. The fast photocurrent imaging testing device according to claim 1, characterized in that, The laser source (1) is a laser that can emit one wavelength or / and multiple wavelengths.
3. The fast photocurrent imaging testing device according to claim 1, characterized in that, The galvanometer (3) is an optical device that includes at least one single-axis / multi-axis reflector, or an optical device that uses a piezoelectric deflector.
4. The fast photocurrent imaging testing device according to claim 1, characterized in that, The field lens (4) is also used to make the laser beams at different positions focus at the same working distance.
5. The fast photocurrent imaging testing device according to claim 1 or 4, characterized in that, The field lens (4) is at least one lens or a group of lenses.
6. The fast photocurrent imaging testing device according to claim 1, characterized in that, The sample to be tested is placed on the sample stage (5), and the output signal terminal of the sample to be tested is electrically connected to the signal acquisition terminal of the data acquisition device (6).
7. The fast photocurrent imaging testing device according to claim 1, characterized in that, The synchronization signal generator (7) uses a synchronization circuit to send a synchronization signal to the galvanometer (3) and the data acquisition unit (6), causing the galvanometer (3) to deflect and change the position of the laser spot on the sample to be tested, while the data acquisition unit (6) synchronously acquires current / voltage signals.
8. The fast photocurrent imaging testing device according to claim 1, characterized in that, The controller (8) is used to control the synchronous signal generator (7) to output a synchronous electrical signal that enables the laser spot of the galvanometer (3) to move and the data acquisition unit (6) to collect current / voltage signals synchronously. The position of the laser spot does not need to be paused during the test.
9. A test system comprising the fast photocurrent imaging test apparatus according to any one of claims 1 to 8, characterized in that, It also includes an optical path switching device added between the laser source (1) and the beam expander (2) to enable switching between lasers of multiple wavelengths.