Blue light laser special for particle image velocity measurement

Abstract

The utility model relates to the technical field of laser equipment, in particular to a special blue laser for particle image velocimetry, which comprises a shell, a control circuit board and an optical bin are mounted in the shell, an LD laser diode and a beam combining sheet are mounted in the optical bin, a TEC refrigeration sheet is mounted at the bottom of the optical bin, and a plurality of supporting structures are mounted in the optical bin. The LD laser diodes and the beam combining piece are fixed on the base through a supporting structure, the number of the LD laser diodes is at least two, one of the LD laser diodes is fixed through a diode movable support, and the beam combining piece is fixed through a beam combining piece movable support. According to the special blue laser for particle image velocity measurement, the laser is combined into the coaxial light beam by adopting at least two LD laser diodes and combining the beam combining sheet, so that high-power and high-quality pulse laser output is realized. Output light spots have 10-degree divergence angles in the fast axis direction and the slow axis direction, and the requirement of the particle image velocity measurement technology for laser beam characteristics is met.

Description

TECHNICAL FIELD

[0001] The utility model relates to laser equipment technical field, specifically, it relates to particle image velocimetry special blue light laser. BACKGROUND

[0002] In the field of particle image velocimetry (PIV), laser illumination scheme is the key component in the whole system, and has a vital influence on the accuracy and reliability of measurement results. PIV technology is a non-contact flow field measurement technology, which obtains the velocity distribution information of flow field by shooting and analyzing the images of tracer particles in the flow field. In order to obtain clear particle images, high-quality laser illumination is essential.

[0003] At present, the traditional PIV illumination mode mainly includes three kinds of low-frequency lamp pumped pulse laser, high-frequency DPSS pumped pulse laser and continuous laser.

[0004] Low-frequency lamp pumped pulse laser generates pulse laser by low-frequency lamp pumping. It can provide high brightness illumination. However, the cost is high, which is about 200,000 yuan to several million yuan, limiting its wide application. In addition, the whole laser system needs huge heat dissipation, which has certain requirements for ventilation, indoor temperature control, noise and vibration, and the ventilation of the heat sink will greatly interfere with the measured object (such as air flow), resulting in deviation of measurement.

[0005] High-frequency DPSS pumped pulse laser generates pulse laser by using high-frequency DPSS technology. It also has high brightness. However, the cost is also high, which is comparable to low-frequency lamp pumped pulse laser, and also has the problem of strict requirements for the use environment.

[0006] Continuous laser provides continuous laser output. The cost is relatively low. However, it cannot meet the requirements of short cross-frame time measurement, and there are also deficiencies in illumination brightness, which makes it difficult to effectively measure high-speed flow field. In addition, high-power continuous laser is mostly red, but in the field of particle image velocimetry, the photosensitivity of special cameras to blue light and green light is higher, while the photosensitivity of red light is lower. On the other hand, red light is more easily absorbed by water than blue light laser, which is an unfavorable factor when using PIV technology to measure water flow. UTILITY MODEL CONTENTS

[0007] The utility model aims at providing particle image velocimetry special blue light laser to solve the problems of certain limitations of the existing PIV illumination mode in cost, performance and use environment and the like in the above background technology.

[0008] In order to achieve the above object, the utility model provides a particle image velocimetry special blue light laser, including the shell, control circuit board, optical storehouse are installed in the shell, the inside installation of optical storehouse has LD laser diode, beam combiner, the bottom of optical storehouse is installed TEC refrigeration piece, the inside installation of optical storehouse has a plurality of support structure, LD laser diode, beam combiner all are fixed on the base through support structure, the number of LD laser diode is at least 2, wherein one LD laser diode is fixed through diode movable support, the beam combiner is fixed through beam combiner movable support.

[0009] As preferred, the optical storehouse includes a base, the top of the base is installed with an outer cover, one end of the optical storehouse is provided with an output window.

[0010] As preferred, the LD laser diode outputs high-power pulsed laser, the beam combiner combines the laser emitted by two LD laser diodes into a coaxial light beam, and the output light spot has a divergence angle of 10 degrees in the fast axis and slow axis directions.

[0011] As preferred, the control circuit board is connected with an external circuit through a circuit connector group.

[0012] As preferred, one end of the shell is installed with an outlet end cover, the end of the shell is provided with a plurality of threaded holes, the threaded holes are used for connecting external optical devices, and the top of the shell is installed with a top cover.

[0013] As preferred, the bottom surface of the shell is provided with a plurality of mounting holes, and the mounting holes are used for connecting a tripod head.

[0014] As preferred, the base and the support structure are both made of red copper material.

[0015] As preferred, the bottom of the diode movable support is provided with a strip-shaped hole on both sides, which can adjust the position forward and backward and is locked and fixed in the optical storehouse through bolts.

[0016] As preferred, the top of the beam combiner movable support is installed with a fixed table, the back of the fixed table is locked and fixed on the beam combiner movable support through bolts, and the bottom of the beam combiner is welded and fixed on the fixed table.

[0017] Compared with the prior art, the utility model has the beneficial effects that:

[0018] In the particle image velocimetry special blue light laser, at least two LD laser diodes are adopted, and the laser is combined into a coaxial light beam by combining the beam combiner, so that high-power and high-quality pulsed laser output is realized. The output light spot has a divergence angle of 10 degrees in the fast axis and slow axis directions, which meets the requirements of the particle image velocimetry technology on the characteristics of the laser beam.

[0019] Both the LD laser diode and the beam combiner are fixed by movable supports, allowing their positions to be adjusted forward and backward and locked with bolts, thus achieving flexible adjustability of the optical system. This design enables the laser to adapt to different measurement needs, improving the versatility and practicality of the equipment.

[0020] A TEC (Cooling Device) is installed at the bottom of the optical chamber to effectively control the operating temperature of the laser diode, improving the stability and lifespan of the laser. This efficient heat dissipation design allows the laser to maintain stable performance over a longer period, reducing malfunctions and performance degradation caused by overheating.

[0021] The control circuit board connects to external circuits via a circuit connector assembly, simplifying the circuit connection process and improving the maintainability of the equipment. Threaded holes are provided on the outer wall of the housing end for easy connection of external optical components, meeting the needs of different measurement scenarios. Mounting holes are provided on the bottom of the housing for easy connection of a tripod head, improving the portability and stability of the equipment. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0023] Figure 2 This is a schematic diagram of the bottom structure of the outer shell in this utility model;

[0024] Figure 3 This is a partial structural schematic diagram of the present invention;

[0025] Figure 4 This is an exploded view of the optical chamber in this utility model;

[0026] Figure 5 This is a partial structural diagram of the support structure in this utility model;

[0027] The meanings of the labels in the diagram are as follows:

[0028] 1. Outer shell; 11. Threaded hole; 12. Mounting hole; 2. Top cover; 3. Optical chamber; 31. Base; 32. Outer cover; 33. LD laser diode; 34. Beam combiner; 35. Support structure; 351. Diode movable support; 352. Beam combiner movable support; 4. Exit end cover; 5. Circuit connector assembly; 6. TEC cooling chip. Detailed Implementation

[0029] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0030] This utility model provides a dedicated blue laser for particle image velocimetry, such as... Figures 1-5 As shown, the device includes a housing 1, inside which a control circuit board and an optical chamber 3 are installed. Inside the optical chamber 3, an LD laser diode 33 and a beam combiner 34 are installed. A TEC cooling plate 6 is installed at the bottom of the optical chamber 3. Several support structures 35 are installed inside the optical chamber 3. The LD laser diode 33 and the beam combiner 34 are both fixed to a base 31 via the support structures 35. There are at least two LD laser diodes 33, one of which is fixed by a diode movable support 351, and the beam combiner 34 is fixed by a beam combiner movable support 352. The housing 1, as the main structure of the laser, integrates core components such as the control circuit board and the optical chamber 3, making the overall structure of the laser compact, easy to carry and install, and improving ease of use.

[0031] The optical chamber 3 contains several support structures 35 that securely fix the LD laser diodes 33 and the beam combiner 34 to the base 31, ensuring accurate positioning and long-term stability of the optical components and effectively preventing displacement caused by vibration or temperature changes. At least two LD laser diodes 33 are used, with at least one fixed by a diode movable support 351. This design not only increases the laser's output power but also allows for fine-tuning of the laser diodes 33's positions to optimize output characteristics and beam quality. The beam combiner 34, fixed by a beam combiner movable support 352, combines the lasers emitted by multiple LD laser diodes 33 into a single coaxial beam, improving energy density and focusing performance. This enables the laser to provide clearer and more accurate illumination in particle imaging velocimetry applications.

[0032] The bottom of the optical chamber 3 is equipped with a TEC cooling chip 6, which can precisely control the operating temperature of the laser diode 33, effectively avoiding performance degradation or damage caused by excessive temperature, and ensuring the long-term stable operation and reliability of the laser.

[0033] In this embodiment, the optical compartment 3 comprises a base 31, the top of the base 31 is mounted with a cover 32, one end of the optical compartment 3 is provided with an output window. The output window is used to isolate the inside of the optical compartment 3 from the outside, prevent dust pollution, and output laser to the outside. The cover 32 is used to isolate the circuit board and the heat of the LD laser diode 33.

[0034] Specifically, the LD laser diode 33 outputs high-power pulsed laser, and the beam combining sheet 34 combines the laser emitted by the two LD laser diodes 33 into a coaxial light beam, and the output light spot has a divergence angle of 10 degrees in the fast axis and slow axis directions. The laser emitted by one of the diodes will pass through the beam combining sheet 34, and the laser emitted by the second diode will be reflected on the surface of the beam combining sheet 34.

[0035] Further, the control circuit board is connected to the external circuit through the circuit connector group 5. The circuit connector group 5 includes a 24V power input of R7B specification, a trigger input of BNC specification, an interlock of quick plug form, a key switch, and a working state indicator. These connectors constitute all the electrical interfaces of the product for interaction with the outside world.

[0036] Further, one end of the housing 1 is mounted with an outlet end cover 4, the end of the housing 1 is provided with a plurality of threaded holes 11, the threaded holes 11 are used to connect external optical devices, and the top of the housing 1 is mounted with a top cover 2.

[0037] Further, the bottom surface of the housing 1 is provided with a plurality of mounting holes 12, the mounting holes 12 are used to connect a tripod head. The mounting holes 12 include a 1 / 4”-20UNC screw hole and a 3 / 8”-16UNC screw hole that do not penetrate, which are used to connect a tripod head. Four 6.5mm through holes with a spacing of 25mm are arranged around the circumference, which are used to connect an optical platform. The tripod head and the optical platform are the most commonly used support devices for fixing similar light sources, and this design improves the convenience of fixing and adjusting.

[0038] Further, the base 31 and the support structure 35 are both made of red copper. During operation, the heat generated by the LD laser diode 33 can be easily conducted to the support structure 35.

[0039] Further, the bottom of the diode movable support 351 is provided with a strip-shaped hole on both sides, which can adjust the position forward and backward and be locked and fixed in the optical compartment 3 by bolts. This forward and backward movement adjustment is used to compensate for the optical path difference between the two diodes caused by the beam combining sheet 34.

[0040] Further, the top of the active support 352 of the beam combiner is provided with a fixed table, the back of the fixed table is fixed on the active support 352 by bolts, and the bottom of the beam combiner 34 is welded and fixed on the fixed table. The fixed table can be rotated to adjust the pitch deflection of the beam combiner 34, and is locked by bolts for strictly coaxial output of the two laser beams. The base 31 is used for conducting heat to the TEC cooling piece 6.

[0041] It is worth noting that the LD laser diode 33 adopts an 8-fold fast-axis compression lens, so that the output spot is approximately square, and the divergence angle is about 10 degrees in the fast axis and the slow axis. The 10-degree divergence angle is the most commonly used divergence angle for particle image velocimetry, which facilitates subsequent external shaping of the optical path.

[0042] The traditional continuous laser refers to a laser diode laser (LD laser) or a diode-pumped solid-state laser (DPSS laser). The characteristics of these two lasers are that the laser is continuously emitted, and the light-emitting device works at the rated voltage or current. Although the laser used in the design is also an LD laser, the working current of the LD laser used in the product will be greater than the rated working current to output higher laser power under low duty cycle working conditions because the target design working mode is pulse.

[0043] The entire circuit is designed to achieve the above goals. In the control circuit board, the DC power input passes through the safety interlock (Interlock) to enter the boost circuit; the boost circuit is controlled by an external signal connected by a BNC connector to generate an LD driving current. This circuit is specially designed to respond to the rising edge of the external TTL control signal within 1.5 microseconds to reach the peak value of the driving current; the driving current passes through the waveform shaping circuit to boost and amplify the waveform of the first few tens of microseconds to meet the highest LD output efficiency requirement. The input signal is limited in the circuit to ensure that the input signal is in a low duty cycle working condition, otherwise the laser indicator light will prompt an error.

[0044] A separate area of the control circuit is used for TEC cooling piece 6 control. The cooling piece does not work when the temperature is lower than the set threshold, and cools when the temperature is higher than the threshold, conducting heat to the casing.

[0045] The particle image velocimetry special blue laser of the utility model in use, first shell 1 as the main structure of the laser, integrated control circuit board, optical warehouse 3 and other core components inside. This integrated design makes the laser overall structure compact, convenient to carry and install, improves the convenience of use.

[0046] The optical compartment 3 is designed with several support structures 35 that firmly fix the LD laser diodes 33 and the beam combiner 34 on the base 31. This design ensures accurate positioning and long-term stability of the optical elements, effectively avoiding displacement of the optical elements due to vibration or temperature changes.

[0047] The number of LD laser diodes 33 is at least 2, of which at least one is fixed by the diode movable support 351. This design not only increases the output power of the laser, but also allows fine-tuning of the position of the laser diodes 33 to optimize the output characteristics and beam quality of the laser. The beam combiner 34 is fixed by the beam combiner movable support 352 and can combine the laser beams emitted by the two LD laser diodes 33 into a coaxial beam. Specifically, the laser emitted by one of the diodes will pass through the beam combiner 34, and the laser emitted by the second diode will be reflected on the surface of the beam combiner 34, resulting in an output spot with a divergence angle of 10 degrees in both the fast and slow axes. This design improves the energy density and focusing performance of the laser, enabling the laser to provide clearer and more accurate illumination in particle image velocimetry applications.

[0048] The bottom of the optical compartment 3 is equipped with a TEC cooling plate 6. This cooling plate cools when the temperature is higher than the set threshold, conducting heat to the casing (i.e. the housing 1), effectively preventing performance degradation or damage to the LD laser diodes 33 due to excessive temperature, ensuring long-term stable operation and reliability of the laser.

[0049] The control circuit board is connected to the external circuit through the circuit connector set 5. The circuit connector set 5 includes a 24V power input of R7B specification, a trigger input of BNC specification, an interlock in fast plug form, a key switch, and a working status indicator light, etc., which constitutes all the electrical interfaces for the laser to interact with the outside world. In the control circuit board, the DC power input passes through the safety interlock to enter the boost circuit. The boost circuit is controlled by the external signal connected by the BNC connector to generate the LD driving current. This circuit is specially designed to respond to the rising edge of the external TTL control signal within 1.5 microseconds to reach the peak value of the driving current. The driving current passes through the waveform shaping circuit to amplify the waveform of the first few tens of microseconds to meet the highest LD output efficiency requirement. At the same time, the input signal is limited in the circuit to ensure that the input signal is in low duty cycle condition, otherwise the laser indicator light will prompt an error.

[0050] The end of the housing 1 is provided with an outlet end cover 4 for protecting the internal structure of the laser and outputting laser. The outer wall of the end of the housing 1 is provided with a plurality of threaded holes 11 for connecting external optical devices. The top of the housing 1 is provided with a top cover 2 for further sealing and protecting the internal structure of the laser. The bottom surface of the housing 1 is provided with a plurality of mounting holes 12, including a 1 / 4" -20 UNC screw hole and a 3 / 8" -16 UNC screw hole, for connecting a tripod head. Four 6.5mm through holes are arranged at intervals of 25mm, for connecting an optical platform. This design improves the convenience of laser fixing and adjustment.

[0051] The optical compartment 3 includes a base 31 and a cover 32. The base 31 is used to support and fix the optical elements, and to conduct heat to the TEC cooling plate 6. The cover 32 is used to isolate the circuit board and the LD laser diode 33 from heat, and to protect the optical elements from heat. The bottom of the diode movable support 351 is provided with a strip-shaped hole on both sides, which can be adjusted in front and back and locked by a bolt. This front and back movement adjustment is used to compensate for the optical path difference between the two diodes caused by the beam combining plate 34.

[0052] A fixed table is mounted on the top of the beam combining plate movable support 352, and the back of the fixed table is fixed on the beam combining plate movable support 352 by a bolt. The bottom of the beam combining plate 34 is welded and fixed on the fixed table. The fixed table can be rotated to adjust the pitch deflection of the beam combining plate 34, ensuring that the two laser beams are strictly coaxial.

[0053] The LD laser diode 33 uses an 8x fast-axis compression lens to make the output spot approximately square, and maintains about 10 degrees of divergence in the fast and slow axes. This design facilitates the design of the subsequent external shaping optical path of the machine body, meeting the application requirements of particle image velocimetry.

[0054] Finally, it should be noted that the circuit connector group 5 and other electronic components in the above components are all general standard components or components known to those skilled in the art, and their structure and principle are known to those skilled in the art through technical manuals or through conventional experimental methods. In the free space of the device, all the above electronic components are connected by wires, and the specific connection means should be referred to the above working principle to complete the electrical connection according to the working order of each electronic component. They are all known technologies in the art.

[0055] The basic principle, main features and advantages of the present application are shown and described above. It should be understood by those skilled in the art that the present application is not limited by the above examples, and the above examples and descriptions in the specification are only preferred examples of the present application and are not intended to limit the present application. Without departing from the spirit and scope of the present application, various changes and improvements can be made to the present application, and these changes and improvements all fall within the scope of the claimed present application. The scope of protection of the present application is defined by the appended claims and their equivalents.

Claims

1. A dedicated blue laser for particle image velocimetry, comprising a housing (1), characterized in that: The shell (1) is internally provided with a control circuit board and an optical bin (3), the optical bin (3) is internally provided with an LD laser diode (33) and a beam combining sheet (34), the bottom of the optical bin (3) is provided with a TEC cooling sheet (6), and the optical bin (3) is internally provided with a plurality of support structures (35), and the LD laser diode (33) and the beam combining sheet (34) are fixed on the base (31) through the support structures (35).

2. The dedicated blue laser for particle image velocimetry according to claim 1, characterized in that: The number of the LD laser diode (33) is at least two, one of which is fixed through a diode movable support (351), and the beam combining sheet (34) is fixed through a beam combining sheet movable support (352).

3. The PIV dedicated blue laser of claim 1, wherein: The optical bin (3) comprises a base (31), the top of the base (31) is provided with an outer cover (32), and one end of the optical bin (3) is provided with an output window.

4. The dedicated blue laser for particle image velocimetry according to claim 2, wherein: The LD laser diode (33) outputs high-power pulsed laser, and the beam combining sheet (34) combines the laser emitted by two LD laser diodes (33) into a coaxial light beam, and the output light spot has a divergence angle of 10 degrees in the fast axis and slow axis directions.

5. The PIV dedicated Blu-ray laser of claim 1, wherein: The control circuit board is connected with an external circuit through a circuit connector group (5).

6. The dedicated blue laser for particle image velocimetry according to claim 1, wherein: One end of the shell (1) is provided with an outlet end cover (4), the end of the shell (1) is provided with a plurality of threaded holes (11), the threaded holes (11) are used for connecting external optical devices, and the top of the shell (1) is provided with a top cover (2).

7. The PIV dedicated Blu-ray laser of claim 1, wherein: The bottom surface of the shell (1) is provided with a plurality of mounting holes (12), and the mounting holes (12) are used for connecting a tripod head.

8. The PIV dedicated Blu-ray laser of claim 3, wherein: The base (31) and the support structure (35) are made of red copper material.

9. The PIV dedicated Blu-ray laser of claim 2, wherein: The diode movable support (351) is provided with a strip-shaped hole at the bottom of both sides, which can adjust the position forward and backward and is locked and fixed in the optical bin (3) through a bolt.

10. The dedicated blue laser for particle image velocimetry according to claim 2, wherein: The top of the beam combining sheet movable support (352) is provided with a fixed table, the back of the fixed table is locked and fixed on the beam combining sheet movable support (352) through a bolt, and the bottom of the beam combining sheet (34) is welded and fixed on the fixed table.

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