Laser module with over-temperature protection, preparation method and control system

Abstract

The invention discloses a laser module with over-temperature protection, a preparation method and a control system, and mainly solves the technical problems that the temperature obtained in the prior art is not accurate enough, the temperature of a chip is too high and even the chip fails easily, and the like. The laser module comprises a substrate, a chip unit, a temperature monitoring unit and a heat sink, the chip unit and the temperature monitoring unit are welded on the upper surface of the substrate; the chip unit comprises a plurality of first chip assemblies and a plurality of second chip assemblies which are sequentially connected in series or in parallel; the first chip assemblies and the second chip assemblies are equal in number and structure, and each first chip assembly and the corresponding second chip assembly comprise a laser chip bar and first tungsten copper electrodes welded to the two sides of the laser chip bar. The temperature monitoring unit is a PTC (Positive Temperature Coefficient) resistor, is positioned between the first chip assembly and the second chip assembly which are close to each other, and is respectively connected in series with the first tungsten copper electrodes of the first chip assembly and the second chip assembly; the heat sink is welded to the lower surface of the substrate and used for adjusting the temperature of the chip unit.

Description

Technical Field

[0001] The present invention relates to a semiconductor laser, and in particular to a laser module with over-temperature protection, a preparation method and a control system. Background Art

[0002] With the development of technology, lasers have been fully applied in various fields, especially semiconductor lasers, which have been widely used in material processing, medical cosmetology, lidar, aerospace and other fields due to their small size, high efficiency, easy integration and maintenance-free.

[0003] In order to ensure that the energy of the laser module meets the use requirements, multiple bar chips are generally assembled in parallel or series to increase the power. However, in actual use, due to the high power density and small size of the laser module, it is easy to cause the operating temperature of the internal chip to be too high, so the chip needs to be protected from overheating.

[0004] The prior art usually involves drilling a hole in the heat sink at the bottom of the chip, placing a temperature measuring device in the hole to monitor the temperature of the laser chip, and feeding the monitored temperature back to the control system. The control system reduces the power of the laser module, thereby reducing the heat loss of the chip and achieving over-temperature protection for the chip. However, since this method monitors the temperature through the heat sink at the bottom of the chip, the temperature monitoring point and the chip are far apart and not in direct contact, the collected temperature is not accurate enough, which can easily cause the collected temperature to be within the allowable range, while the temperature of the chip itself is too high, resulting in the burning of the chip. In addition, it takes a certain amount of time for the temperature measuring device to feed back the collected temperature data to the control system, which can easily cause the chip temperature to be too high or even fail. Summary of the invention

[0005] The purpose of the present invention is to solve the technical problems that the temperature obtained by the existing over-temperature protection method is not accurate enough and is easy to cause the chip temperature to be too high or even fail, and to provide a laser module with over-temperature protection, a preparation method and a control system.

[0006] In order to achieve the above objectives, the technical solutions provided by the present invention are as follows:

[0007] A laser module with over-temperature protection, which is special in that:

[0008] It includes a substrate, a chip unit, a temperature monitoring unit and a heat sink;

[0009] The chip unit and the temperature monitoring unit are both welded to the upper surface of the substrate; the chip unit comprises a plurality of first chip components and a plurality of second chip components which are sequentially connected in series or in parallel; the first chip components and the second chip components are equal in number and have the same structure, and respectively comprise a laser chip bar and a first tungsten copper electrode welded to both sides of the laser chip bar;

[0010] The temperature monitoring unit is a PTC resistor, which is located between the first chip component and the second chip component that are close to each other, and the two ends are respectively connected in series with the first tungsten copper electrodes of the first chip component and the second chip component;

[0011] The heat sink is welded to the lower surface of the substrate and is used to adjust the temperature of the chip unit.

[0012] Furthermore, the initial value R(T) of the PTC resistor is: R(T)=nR(0), wherein n is the number of laser chip bars, and R(0) is a constant.

[0013] Furthermore, two ends of the PTC resistor are connected in series with first tungsten-copper electrodes of the adjacent first chip assembly and second chip assembly through second tungsten-copper electrodes.

[0014] Furthermore, the substrate is an aluminum nitride ceramic substrate.

[0015] At the same time, the present invention also provides a method for preparing a laser module with over-temperature protection, comprising the following steps:

[0016] Step 1: Prepare the substrate and heat sink according to the preset requirements of the laser module power, and select a PTC resistor with a corresponding resistance value;

[0017] Step 2, welding first tungsten-copper electrodes on both sides of each laser chip bar, and sintering through a eutectic furnace to obtain a plurality of first chip assemblies and a plurality of second chip assemblies, wherein the number of the first chip assemblies and the second chip assemblies are equal and the structure is the same;

[0018] Step 3, welding the plurality of first chip assemblies and the plurality of second chip assemblies obtained in step 2 and the PTC resistor selected in step 1 in series or in parallel, and sintering them in a eutectic furnace to obtain a laser module; the PTC resistor is located between the first chip assemblies and the second chip assemblies that are close to each other;

[0019] Step 4: weld the laser module to the upper surface of the substrate, and then weld the lower surface of the substrate to the heat sink to obtain a laser module with over-temperature protection.

[0020] Furthermore, in step 1, the number n of the laser chip bars is equal to the preset power of the laser module divided by the power of each laser chip bar;

[0021] The initial value R(T) of the PTC resistor is: R(T)=nR(0), where R(0) is a constant.

[0022] Furthermore, in step 2, the welding is performed using gold-tin solder; and the temperature in the eutectic furnace is controlled within 330°C.

[0023] Furthermore, in step 3, the welding is performed using indium silver solder; the temperature in the eutectic furnace is controlled within 180° C.;

[0024] The PTC resistor is welded in series with the first tungsten-copper electrodes of the adjacent first chip assembly and the second chip assembly respectively through the second tungsten-copper electrodes.

[0025] In addition, the present invention also provides a laser module control system with over-temperature protection, which is special in that:

[0026] It includes a control unit and the above-mentioned laser module with over-temperature protection;

[0027] The control unit is respectively connected to the first tungsten copper electrodes of the first chip assembly and the second chip assembly located at the outermost side, and is used to monitor the voltage at both ends of the laser module and adjust the power of the laser module.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] 1. The laser module with over-temperature protection of the present invention is provided with a PTC resistor between a first chip component and a second chip component close to each other. Since this is the highest temperature area of ​​the chip unit, the temperature of the chip unit can be detected more accurately by providing the PTC resistor there. Since the resistance of the PTC resistor increases with the increase of temperature, when the temperature of the PTC resistor reaches a certain value, its resistance will rise sharply, thereby causing the resistance of the entire chip unit to rise sharply, thereby reducing the power of the chip unit and realizing over-temperature protection of the laser module.

[0030] 2. The present invention determines the number of laser chip bars according to the preset requirements of the laser module power, selects the PTC resistor with the corresponding resistance, and then sequentially welds the first chip assembly consisting of the laser chip bars and the first tungsten copper electrode, the second chip assembly, the PTC resistor, the substrate, and the heat sink to prepare a laser module with over-temperature protection. This method is applicable to the preparation of laser modules of different powers with over-temperature protection, has a wide range of applications, and is highly versatile.

[0031] 3. The present invention has a laser module control system with over-temperature protection. Since the PTC resistance increases with the temperature, the voltage across the laser module will also increase. The control unit can achieve the purpose of temperature detection through the voltage across the laser module, and then adjust the power of the laser module to achieve over-temperature protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 The figure is a schematic structural diagram of a laser module with over-temperature protection according to an embodiment of the present invention.

[0033] Figure 2 The figure is a schematic diagram of the position structure of a first chip component, a PTC resistor, and a second chip component in an embodiment of a laser module with over-temperature protection of the present invention.

[0034] Figure 3 The figure is a schematic structural diagram of a first chip assembly in an embodiment of a laser module with over-temperature protection according to the present invention.

[0035] Figure 4 This is a characteristic diagram of the change of PTC resistance with temperature in an embodiment of a laser module with over-temperature protection of the present invention.

[0036] The reference numerals are as follows:

[0037] 1-substrate, 2-heat sink, 3-first chip assembly, 4-second chip assembly, 5-laser chip bar, 6-first tungsten copper electrode, 7-PTC resistor, 8-second tungsten copper electrode. DETAILED DESCRIPTION

[0038] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0039] Reference Figure 1 ,picture, Figure 3 This embodiment provides a laser module with over-temperature protection, including a substrate 1, a chip unit, a temperature monitoring unit and a heat sink 2; wherein the chip unit and the temperature monitoring unit are both welded to the upper surface of the substrate 1, and the substrate 1 is an aluminum nitride ceramic substrate.

[0040] The chip unit includes a plurality of first chip components 3 and a plurality of second chip components 4 which are sequentially connected in series or in parallel; the first chip components 3 and the second chip components 4 are equal in number and have the same structure, and respectively include a laser chip bar 5 and a first tungsten copper electrode 6 welded on both sides of the laser chip bar 5 ( Figure 3 shown).

[0041] The temperature monitoring unit is a PTC resistor 7, which is a positive temperature coefficient resistor. The resistance of the PTC resistor 7 increases sharply as the temperature rises ( Figure 4As shown), the power of the laser module is reduced, the current is lowered, and the chip is prevented from being burned.

[0042] Reference Figure 2 The PTC resistor 7 is located between the first chip assembly 3 and the second chip assembly 4, and both ends are connected in series with the first tungsten copper electrodes 6 of the first chip assembly 3 and the second chip assembly 4 through the second tungsten copper electrodes 8. In this embodiment, the PTC resistor 7 is arranged inside the chip unit of the laser module, so that the temperature sampling is more accurate.

[0043] The initial value R(T) of the PTC resistor 7 is: R(T)=nR(0), where n is the total number of laser chip bars 5 and R(0) is a constant. The value of R(0) is generally determined according to the internal resistance of the laser chip bars 5.

[0044] The heat sink 2 is welded to the lower surface of the substrate 1 to adjust the temperature of the chip unit in real time. The contact area between the heat sink 2 and the substrate 1 is generally equal to or slightly larger than the area of ​​the lower surface of the substrate 1 to ensure that the heat from the chip unit can be dissipated in time.

[0045] At the same time, this embodiment also provides a method for preparing a laser module with over-temperature protection, comprising the following steps:

[0046] Step 1: Prepare the substrate 1 and the heat sink 2 according to the preset requirements of the laser module power, and select the PTC resistor 7 with the corresponding resistance value.

[0047] In this embodiment, the number n of laser chip bars 5 is equal to the preset power of the laser module divided by the power of each laser chip bar 5. For example, when the power of the laser module needs to be less than 1000W, 10 100W laser chip bars can be selected. The resistance of the PTC resistor 7 at room temperature (25°C) is called the initial value. When the power of the laser module needs to be less than 1000W, the initial value of the PTC resistor 7 generally needs to be less than 1 ohm, and R(0) takes a value of 0.1 ohm. When the temperature of the chip unit is greater than 90°C, the resistance of the PTC resistor 7 increases with the increase of temperature, and can increase to 10 times (i.e., 10 ohms). Therefore, there is a positive proportional relationship between the selection of the initial value of the PTC resistor 7 and the power of the laser module. The greater the power of the laser module, the larger the selected initial value, so that the false protection will not be triggered due to the change of the resistance of the power device itself.

[0048] Step 2: Use gold-tin solder to weld the first tungsten-copper electrodes 6 on both sides of each laser chip bar 5, and sinter them at a maximum temperature of 330° C. in a eutectic furnace to obtain a plurality of first chip components 3 and a plurality of second chip components 4, wherein the number of first chip components 3 and the second chip components 4 are equal and the structure is the same, and each first chip component 3 and each second chip component 4 are Figure 3 The "sandwich" structure shown.

[0049] Step 3: weld the multiple first chip assemblies 3 and the multiple second chip assemblies 4 obtained in step 2 and the PTC resistor 7 selected in step 1 in series or in parallel, and sinter them in a eutectic furnace to obtain a laser module.

[0050] In this embodiment, the PTC resistor 7 is located at the center of the entire chip unit, that is, between the first chip assembly 3 and the second chip assembly 4 which are close to each other, and this position is the position with the highest temperature in the entire laser module; then, indium silver solder is used for welding, and sintered at a maximum temperature of 180°C in a eutectic furnace to obtain a laser module. In this process, the PTC resistor 7 is welded in series with the first tungsten copper electrode 6 of the adjacent first chip assembly 3 and the second chip assembly 4 through the second tungsten copper electrode 8.

[0051] Step 4: weld the laser module to the upper surface of the substrate 1, and then weld the lower surface of the substrate 1 to the heat sink 2, so as to obtain a laser module with over-temperature protection.

[0052] Finally, the welded laser module undergoes wire welding, shell installation and other processes, and the product is installed in the laser control system. The control system detects the voltage of the laser module to achieve the purpose of temperature detection.

[0053] This embodiment also provides a laser module control system with over-temperature protection, including a control unit and a laser module with over-temperature protection, wherein the control unit is respectively connected to the first tungsten copper electrode 6 located at the outermost first chip component 3 and the second chip component 4, and is used to monitor the voltage across the laser module and adjust the power of the laser module.

[0054] The present invention provides dual protection for the laser module by connecting the PTC resistor 7 in series in the chip unit of the laser module: first, since the PTC resistor 7 is encapsulated in the laser module and is in direct contact with the chip unit, the temperature detection is more accurate. After the temperature of the PTC resistor 7 reaches a certain value, the resistance will rise sharply with the temperature, and then the resistance of the entire laser module will rise sharply, thereby reducing the power of the laser module and achieving over-temperature protection of the laser module. Second, since the PTC resistor 7 increases with the increase of temperature, at the same time, the voltage at both ends of the laser module will also increase. The control software in the control unit achieves the purpose of temperature detection by detecting the voltage at both ends of the laser module, and finally adjusts the power of the laser module to protect it from over-temperature.

[0055] Although the above embodiments have described the present invention in detail, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or make equivalent replacements for some or all of the technical features therein, and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the present invention.

Claims

1. A laser module with over-temperature protection, characterized in that: It comprises a substrate (1), a chip unit, a temperature monitoring unit and a heat sink (2); The chip unit and the temperature monitoring unit are both welded to the upper surface of the substrate (1); the chip unit comprises a plurality of first chip components (3) and a plurality of second chip components (4) which are sequentially connected in series or in parallel; the first chip components (3) and the second chip components (4) are equal in number and have the same structure, and respectively comprise a laser chip bar (5) and a first tungsten copper electrode (6) welded to both sides of the laser chip bar (5); The temperature monitoring unit is a PTC resistor (7), which is located between a first chip component (3) and a second chip component (4) that are close to each other, and whose two ends are respectively connected in series with the first tungsten copper electrodes (6) of the first chip component (3) and the second chip component (4); The heat sink (2) is welded to the lower surface of the substrate (1) and is used to adjust the temperature of the chip unit.

2. The laser module with over-temperature protection according to claim 1, characterized in that: The initial value R(T) of the PTC resistor (7) is: R(T)=nR(0), wherein n is the number of laser chip bars (5) and R(0) is a constant.

3. The laser module with over-temperature protection according to claim 2, characterized in that: The two ends of the PTC resistor (7) are respectively connected in series with the first tungsten-copper electrodes (6) of the adjacent first chip component (3) and the second chip component (4) via the second tungsten-copper electrodes (8).

4. The laser module with over-temperature protection according to claim 1, 2 or 3, characterized in that: The substrate (1) is an aluminum nitride ceramic substrate.

5. A method for preparing a laser module with over-temperature protection according to any one of claims 1 to 4, characterized in that: The following steps are involved: Step 1: Prepare a substrate (1) and a heat sink (2) according to the preset requirements of the laser module power, and select a PTC resistor (7) with a corresponding resistance value; Step 2, welding first tungsten copper electrodes (6) on both sides of each laser chip bar (5), and sintering through a eutectic furnace to obtain a plurality of first chip assemblies (3) and a plurality of second chip assemblies (4), wherein the number of the first chip assemblies (3) and the second chip assemblies (4) are equal and the structure is the same; Step 3, sequentially welding the plurality of first chip assemblies (3) and the plurality of second chip assemblies (4) obtained in step 2, and the PTC resistor (7) selected in step 1 in series or in parallel, and sintering them in a eutectic furnace to obtain a laser module; the PTC resistor (7) is located between the first chip assembly (3) and the second chip assembly (4) that are close to each other; Step 4: weld the laser module to the upper surface of the substrate (1), and then weld the lower surface of the substrate (1) to the heat sink (2), so as to obtain a laser module with over-temperature protection.

6. The method for preparing a laser module with over-temperature protection according to claim 5, characterized in that: In step 1, the number n of the laser chip bars (5) is equal to the preset power of the laser module divided by the power of each laser chip bar (5); The initial value R(T) of the PTC resistor (7) is: R(T)=nR(0), wherein R(0) is a constant.

7. The method for preparing a laser module with over-temperature protection according to claim 6, characterized in that: In step 2, the welding is performed using gold-tin solder; the temperature in the eutectic furnace is controlled within 330°C.

8. The method for preparing a laser module with over-temperature protection according to claim 7, characterized in that: In step 3, the welding is performed using indium silver solder; the temperature in the eutectic furnace is controlled within 180° C.; The PTC resistor (7) is welded in series with the first tungsten-copper electrodes (6) of the adjacent first chip assembly (3) and the second chip assembly (4) respectively via the second tungsten-copper electrodes (8).

9. A laser module control system with over-temperature protection, characterized in that: Comprising a control unit and a laser module with over-temperature protection as claimed in any one of claims 1 to 4; The control unit is respectively connected to the first tungsten copper electrodes (6) located on the outermost first chip assembly (3) and the second chip assembly (4), and is used to monitor the voltage at both ends of the laser module and adjust the power of the laser module.

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