A three-dimensional temperature measuring absorption cavity type laser power detector

Abstract

The application discloses a three-dimensional temperature measuring absorption cavity type laser power detector, which adopts a three-dimensional temperature measuring element to measure the temperature distribution on the surface and inside of an absorption cavity, and realizes accurate measurement of laser power. The laser power detector comprises a reflecting cone, an absorption cavity, a three-dimensional temperature measuring assembly, a shell and the like. The reflecting cone is installed at the bottom of the absorption cavity, and the tip of the cone is opposite to the direction of a laser incident port. The absorption cavity has a smooth cylindrical or V-shaped circular groove structure, and the inner wall surface of the absorption cavity is provided with a high-absorptivity, good-heat-conductivity and high-temperature-resistant coating. A series of through holes are distributed on the absorption cavity, and the three-dimensional temperature measuring assembly is installed in the through holes. The periphery of the absorption cavity is processed into a fin structure and is placed in a flowing water environment. The shell is provided with holes for water inlet and water outlet, so that water cooling and heat dissipation are realized. The laser power detector can not only improve the spatial uniformity and accuracy of power measurement, but also is convenient to install and integrate.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of laser radiation parameter measurement, and relates to a laser power measuring device, in particular to a high-power laser power detector. BACKGROUND

[0002] With the rapid development of laser technology, the output power of the laser is continuously improved. For example, the output power of a single module of the fiber laser developed in recent years has reached more than ten kilowatts, and the output power of the multi-mode laser has broken through 100 kW. The industrial processing equipment based on high-power laser is widely used, thereby promoting the faster development of laser technology. With the improvement of the level of laser power, corresponding laser power measuring equipment needs to be equipped for performance monitoring and evaluation.

[0003] The current high-power laser power meter generally adopts the calorimetric method for laser power measurement, but the performance in the spatial uniformity is poor, which is manifested as that when different sizes of laser beams are irradiated, the measured power values are quite different. This is because most of the existing laser power meters reflect the incident laser to the inner wall of the absorption cavity through a reflection cone, and measure the temperature rise of the end face of the absorption cavity to realize the measurement of the laser power. Since the distribution of the laser beams of different sizes on the inner wall of the absorption cavity is different after being reflected by the reflection cone, the temperature rise of the end face of the absorption body measured in a certain time is also different, thereby causing a large measurement error. SUMMARY

[0004] The technical problem to be solved by the present application is to provide a new laser power detector with good uniformity, high accuracy and stable performance.

[0005] The technical scheme of the present application is as follows:

[0006] A three-dimensional temperature measurement absorption cavity type laser power detector measures the temperature change in the absorption cavity through a temperature measurement element to realize the measurement of the laser power. The laser power detector comprises a reflection cone, an absorption cavity, a three-dimensional temperature measurement assembly, a shell and the like. The reflection cone is installed at the bottom of the absorption cavity. The three-dimensional temperature measurement assembly is annularly distributed in the absorption cavity. The absorption cavity is peripherally processed into a fin structure. The reflection cone, the absorption cavity and the temperature measurement element are arranged in the shell.

[0007] Specifically, the reflection cone is installed at the bottom of the absorption cavity, and the tip of the cone is opposite to the direction of the laser incident port of the laser power detector, which is used to reflect the incident laser to the inner wall of the absorption cavity. The surface of the reflection cone is coated with a high reflectivity film layer to greatly improve the reflectivity of the measured laser, so that the measured laser is reflected to the inner wall of the absorption cavity and is absorbed.

[0008] The inner wall of the absorption cavity can adopt two structures, one is a smooth cylindrical shape, and the other comprises a series of V-shaped circular ring groove structures. The above two kinds of absorption cavity inner wall structures can be used for absorbing the light beams reflected from the reflecting cone and converting them into heat energy. Compared with the smooth cylindrical inner wall, the V-shaped circular ring groove structure can increase the light absorption area, reduce the laser power density, and thus improve the anti-laser damage capability of the laser power detector. The absorption cavity inner wall is treated by a surface treatment process to improve its laser absorption rate and achieve uniform absorption of laser.

[0009] The absorption cavity is uniformly distributed with a series of through holes around its central symmetry axis for mounting the temperature measuring elements. Among them, the temperature measuring elements close to the inner wall of the absorption cavity are used to measure the hot end temperature, and the temperature measuring elements close to the outer heat dissipation fins of the absorption cavity are used to measure the cold end temperature. In order to realize three-dimensional temperature measurement, i.e. to obtain the temperature distribution at different positions on the surface and inside the absorber, the temperature measuring elements are grouped every N (N≥3) and attached to the through holes of the absorption cavity. The following three methods can be used for the installation and attachment of the temperature measuring elements:

[0010] The first method is to process M through holes uniformly distributed along the circumference on the absorption cavity, which are connected to the hot end and the cold end. The temperature measuring elements are connected in series every N to form a group, and are attached to the inner wall of the through holes close to the hot end and the cold end, respectively.

[0011] The second method is to process M independent through holes uniformly distributed along the circumference at the hot end ring and the cold end ring positions of the absorption cavity. The temperature measuring elements are connected in series every N to form a group, and are attached to the inner wall of one side of the hot end through hole and the inner wall of one side of the cold end through hole, respectively.

[0012] The third method is to process M through holes uniformly distributed along the circumference on the absorption cavity, which are connected to the hot end and the cold end, and to process M heat conduction blocks matching the shape and size of the through holes. The temperature measuring elements are connected in series every N to form a group, and are attached to the hot end face and the cold end face of each heat conduction block, respectively, i.e. each heat conduction block is attached with 2 groups of temperature measuring elements, forming a three-dimensional temperature measurement assembly. M three-dimensional temperature measurement assemblies are inserted into the M through holes, respectively, and are pasted and solidified with heat-conducting glue.

[0013] The periphery of the absorption cavity is processed into a heat dissipation fin structure and placed in a flowing water environment to improve the heat dissipation efficiency.

[0014] The hot end temperature measuring elements can be connected in series or grouped according to actual needs. The cold end temperature measuring elements can be connected in series or grouped according to actual needs. The temperature difference measured by the hot end temperature measuring elements and the cold end temperature measuring elements is used to calculate the power of the laser to be measured.

[0015] The shell can include a front shell and a rear shell, the front shell center area is open as a laser incident port. The rear shell is open as a cable hole for electrical cables, or for mounting electrical interfaces. The side wall of the shell is also provided with a water inlet and outlet for water cooling.

[0016] The absorption cavity and the position of mutual contact of the shell are grooved and mounted with a sealing rubber ring to achieve sealing and waterproof.

[0017] The advantages of the present application compared with the prior art are:

[0018] 1. The present application adopts multiple groups of three-dimensional temperature measurement elements to measure temperature, which can not only measure the temperature of the surface of the absorption cavity, but also measure the temperature inside the absorption cavity, so that the present application can more accurately measure the overall temperature distribution of the absorption cavity. Compared with the conventional technology of measuring only the surface temperature, the measurement uniformity is better and the accuracy is higher.

[0019] 2. The present application proposes multiple installation and attachment methods of three-dimensional temperature measurement elements, which makes the scheme easier to implement and improves the integrated installation efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is the external structure diagram of the laser power detector of the first to third embodiments of the present application;

[0021] Figure 2 is the internal structure diagram of the laser power detector of the first to third embodiments of the present application;

[0022] Figure 3 is the internal structure diagram of the laser power detector of the first to third embodiments of the present application;

[0023] Figure 4 is the absorption cavity structure schematic diagram of the first embodiment of the present application.

[0024] Figure 5 is the absorption cavity structure schematic diagram of the second embodiment of the present application.

[0025] Figure 6 is the temperature measurement element group schematic diagram of the first and second embodiments of the present application.

[0026] Figure 7 is the absorption cavity structure schematic diagram of the third embodiment of the present application.

[0027] Figure 8 is the three-dimensional temperature measurement assembly schematic diagram of the third embodiment of the present application. DETAILED DESCRIPTION

[0028] The present application will be described in detail below in conjunction with the embodiments in the drawings.

[0029] Embodiment One

[0030] Referring to Figures 1-4 and Figure 6 , a three-dimensional temperature measurement absorption cavity type laser power detector of the embodiment includes a reflecting cone 1, an absorption cavity 2, a three-dimensional temperature measurement assembly 3, a housing 5, a water inlet 9, a water outlet 10, and the like.

[0031] The embodiment uses a reflecting absorption measurement principle to measure laser power, that is, incident laser light passes through an incident port 6 of the laser power detector, is irradiated on the reflecting cone 1, is reflected by the reflecting cone 1 to the inner wall of the absorption cavity 2, and the inner wall has two structures. Figure 2 As shown in Figure 3 , the inner wall 201 is a smooth cylindrical structure, and the surface thereof is formed with an absorption coating having high absorption, good thermal conductivity, and high temperature resistance by spraying a special material or a chemical method.

[0032] Figure 4 As shown in , the inner wall 202 is a V-shaped circular groove structure, and the laser light reflected by the reflecting cone to the inner wall can be absorbed after multiple reflections in the V-shaped groove, thereby further reducing the power density. The surface thereof is also formed with an absorption coating having high absorption, good thermal conductivity, and high temperature resistance by spraying a special material or a chemical method.

[0033] The reflecting cone 1 in Embodiment One is made of pure copper, the side surface thereof is conical, and the surface thereof is plated with gold to improve the reflectivity to laser light.

[0034] The absorption cavity 2 is made of pure copper, the inner wall thereof can absorb reflected light from the reflecting cone 1 and convert the reflected light into heat to conduct to the periphery. Two circular grooves 211 and 212 are respectively machined on the front and rear end faces of the absorption cavity 2, and are respectively used for accommodating the wires of the hot end and cold end temperature sensors. The periphery of the absorption cavity 2 is machined into a comb-shaped fin structure 221 and is placed in a flowing water environment to improve the heat dissipation efficiency.

[0035] Figure 6As shown, N temperature measuring elements (temperature sensors) 301 are connected in series, and M three-dimensional temperature measuring assemblies 3 are attached to the inner walls of the M through holes 400 near the hot end and the cold end of the absorption cavity, and are pasted and solidified by using heat-conducting glue, so that the temperature changes of the hot end and the cold end of the absorption cavity can be measured. According to the measured temperature difference between the hot end and the cold end, the laser power to be measured can be calculated.

[0036] The three-dimensional temperature measuring absorption cavity type laser power detector further comprises a shell 5, which comprises two parts of a front shell 501 and a rear shell 502. The front shell 501 is provided with a hole in the middle as a laser entrance 6. The rear shell is provided with a hole on the side as a threading hole 7 for leading the lead wire of the temperature sensor out and connecting with the instrument responsible for control and display through a terminal, and can also be connected with a computer system. The front shell 501 and the rear shell 502 are respectively provided with grooves 8 for installing sealing rings to prevent cooling water from entering the inside of the laser power detector or leaking out from the connection of the shell.

[0037] The working process of the three-dimensional temperature measuring absorption cavity type laser power detector is as follows:

[0038] The laser to be measured is aligned with the entrance 6 of the three-dimensional temperature measuring absorption cavity type laser power detector, the laser passes through the entrance 6 and is reflected on the inner wall 201 (or 202) of the absorption cavity 2 through the reflecting cone 1, the laser energy is absorbed by the inner wall of the absorption cavity 2 and is converted into heat, and the heat is conducted outward along the radial direction of the absorption cavity 2. During the heat conduction process, the temperature of the absorption cavity changes, and the temperature distribution is collected by the multiple temperature sensors on the three-dimensional temperature measuring assembly 3 and transmitted to the external instrument responsible for control and display or the computer system connected thereto. When the temperature reaches equilibrium, according to the measured temperature difference between the hot end and the cold end, the laser power to be measured is obtained through further calculation and processing.

[0039] In this embodiment, the water inlet 9 can be connected with external cooling water, and the cooling water enters the inside of the detector, flows through the peripheral cooling fins 221 of the absorption cavity 2, takes away the heat generated thereby, and is discharged through the water outlet 10.

[0040] Embodiment two:

[0041] Referring to Figures 1-3 , Figures 5-6 As shown, the three-dimensional temperature measuring absorption cavity type laser power detector of this embodiment comprises a reflecting cone 1, an absorption cavity 2, a three-dimensional temperature measuring assembly 3, a shell 5, a water inlet 9, a water outlet 10, etc.

[0042] The working principle of this embodiment is basically the same as that of the aforementioned embodiment one, and the main difference lies in that the through hole structure for attaching the three-dimensional temperature measuring assembly 3 on the absorption cavity 2 is different. Figure 5The structure diagram of the absorption cavity 2 in the embodiment is shown, which includes M hot end through holes 401 and M cold end through holes 402 uniformly distributed along the circumference, and the hot end through holes 401 and the cold end through holes 402 are distributed along the radial direction. Figure 6 The stereoscopic temperature measurement assembly 3 is shown, which is composed of N temperature measurement elements (temperature sensors) in series. M stereoscopic temperature measurement assemblies 3 are sequentially attached to one side end surface of the M hot end through holes 401, and M stereoscopic temperature measurement assemblies 3 are sequentially attached to one side end surface of the M cold end through holes 402, and the stereoscopic temperature measurement assemblies 3 are pasted and solidified in the absorption cavity through holes by using heat-conducting glue.

[0043] Embodiment three:

[0044] Referring to Figures 1-3 , Figures 7-8 The laser power detector of the embodiment includes a reflecting cone 1, an absorption cavity 2, a stereoscopic temperature measurement assembly 3, an outer shell 5, a water inlet 9, a water outlet 10, and the like.

[0045] The working principle is basically the same as that of the aforementioned embodiment one, and the main difference lies in that the structure of the stereoscopic temperature measurement assembly 3 is different. In the embodiment, the absorption cavity 2 also includes M through holes 400 uniformly distributed along the circumferential direction and connecting the hot end and the cold end, and the structure of the stereoscopic temperature measurement assembly 3 is shown in Figure 8 The structure of the stereoscopic temperature measurement assembly 3 is shown, which includes a copper heat-conducting block 302 and two groups of temperature measurement elements 301. The shape and size of the copper heat-conducting block 302 match the through holes 400, and the two groups of temperature measurement elements are composed of N temperature sensors in series, and are pasted on the end surfaces of the copper heat-conducting block 302 close to the hot end and the cold end by using heat-conducting glue. Further, M stereoscopic temperature measurement assemblies 3 are sequentially pasted and solidified in the M through holes 400 of the absorption cavity 2 by using heat-conducting glue.

[0046] The above-described embodiments are only used to describe the implementation of the present application, and are not used to limit the concept and scope of the present application. Various modifications and improvements to the technical solutions of the present application made by those skilled in the art without departing from the design concept of the present application shall fall within the protection scope of the present application, and the scope of the present application is defined by the appended claims rather than the above description, and therefore all changes falling within the meaning and scope of the equivalent elements of the claims shall be included in the present application, and any figure reference in the claims shall not be regarded as limiting the claims.

Claims

1. A stereothermometric absorption cavity type laser power detector, characterized in that, It includes a reflecting cone, an absorption cavity, a stereoscopic temperature measuring assembly, and a shell. The reflecting cone is installed at the bottom of the absorption cavity. The stereoscopic temperature measuring assembly is annularly distributed inside the absorption cavity. The inner wall of the absorption cavity has a smooth cylindrical or V-shaped circular groove structure. The inner wall surface has a high absorption rate, good heat conduction performance, and a high-temperature-resistant coating for absorbing the laser beam reflected from the reflecting cone to the inner wall of the absorption cavity. The integration of the absorption cavity and the stereoscopic temperature measuring assembly includes the following three types: The first type is that the absorption cavity contains M through holes uniformly distributed along the circumference, which are connected to the hot end and the cold end. The stereoscopic temperature measuring assembly is attached to the inner wall near the hot end and the cold end in turn. The stereoscopic temperature measuring assembly is composed of N temperature sensors in series, and N≥3. The second type is that the hot end and the cold end of the absorption cavity have M independent through holes uniformly distributed along the circumference. The stereoscopic temperature measuring assembly is attached to the inner wall on one side of the hot end through hole and the inner wall on one side of the cold end through hole in turn. The stereoscopic temperature measuring assembly is composed of N temperature sensors in series, and N≥3. The third type is that the absorption cavity contains M through holes uniformly distributed along the circumference, which are connected to the hot end and the cold end. Each through hole is installed with one stereoscopic temperature measuring assembly. Each stereoscopic temperature measuring assembly contains a heat-conducting block matched with the shape and size of the through hole and two groups of temperature measuring elements. The two groups of temperature measuring elements are composed of N temperature sensors in series, and N≥3. The stereoscopic temperature measuring assembly is inserted into each through hole in turn and is pasted and solidified with heat-conducting glue. The reflecting cone, the absorption cavity, and the stereoscopic temperature measuring assembly are placed inside the shell. The reflecting cone is made of pure copper and has a conical side surface with a gold-plated surface.

2. A three-dimensional temperature measuring absorption cavity type laser power detector according to claim 1, characterized in that, The reflecting cone is installed at the bottom of the absorption cavity, with the tip of the cone facing the direction of the laser incident port of the laser power detector, for reflecting the incident laser to the inner wall of the absorption cavity.

3. A three-dimensional temperature measuring absorption cavity type laser power detector according to claim 1, characterized in that, The inner wall of the absorption cavity is processed into a smooth cylindrical structure. The inner wall surface forms a high-absorption, good-heat-conduction, and high-temperature-resistant absorption layer through spraying or chemical means.

4. A three-dimensional temperature measuring absorption cavity type laser power detector according to claim 1, characterized in that, The inner wall of the absorption cavity is processed into a V-shaped circular groove structure. The inner wall surface forms a high-absorption, good-heat-conduction, and high-temperature-resistant absorption layer through spraying or chemical means to reduce the laser power density and improve the damage threshold.

5. A three-dimensional temperature measuring absorption cavity type laser power detector according to claim 1, characterized in that, The absorption cavity has a fin structure on the periphery and is placed in a cooling water environment to improve the heat dissipation efficiency.

6. A three-dimensional temperature measuring absorption cavity type laser power detector according to claim 1, characterized in that, The reflecting cone and the absorption cavity are coaxially assembled.

7. A three-dimensional temperature measuring absorption cavity type laser power detector according to claim 1, characterized in that, The shell includes a front shell and a rear shell. The center area of the front shell is opened as a laser incident port. The rear shell is opened as a cable hole for electrical cables or for installing electrical interfaces. The side wall of the shell is also provided with a water inlet and a water outlet for water cooling.

8. A three-dimensional temperature measuring absorption cavity type laser power detector according to claim 1, characterized in that, The position where the absorption cavity and the shell contact each other is grooved and installed with a sealing rubber ring to achieve sealing and waterproofing.

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