Conductive heat dissipation semiconductor side pumping module

Abstract

The invention relates to a conduction heat dissipation semiconductor side pumping module which is characterized in that semiconductor chips are packaged on a metal chip heat sink in an array mode, and a laser working substance is pumped in an end face or side face coupling mode; the clamping structure of the laser working substance sequentially comprises a crystal pressing plate, the working substance, a heat conduction strip and a crystal heat sink from top to bottom, and all the parts are tightly connected together in a pressed mode by fastening the crystal pressing plate. And a groove array is processed at the contact position of the crystal heat sink and the heat conducting strip. And deterioration of laser beam quality caused by influence of mechanical stress on a laser working substance is avoided. The radiation wavelength of the packaged semiconductor pumping chip can be distributed according to a gradient so as to maintain the pumping efficiency consistency of working substances at different environment temperatures. The pumping module can achieve heat balance of temperature in a conduction heat dissipation mode, and power consumption needed by a system is greatly reduced.

Description

Technical Field

[0001] The invention relates to a conductive heat dissipation semiconductor side pump module, which is a semiconductor side pump module structure and is used for the pumping, clamping and heat dissipation structure of laser working materials. Background Art

[0002] High-energy pulsed air-cooled lasers with high repetition rates have been widely used in laser radar, vehicle-mounted and airborne laser ranging, display screen repair, laser-induced breakdown spectroscopy detection and other fields. When injecting high pump power, how to optimize the pump module structure design, conduct the heat generated by the pump source in time, reduce the thermal gradient inside the crystal, and reduce the clamping stress of the working material has become the core of laser design. At present, this type of pump module generally uses devices such as TEC refrigeration sheets for temperature control, and uses the Peltier effect to conduct the heat generated by the pump module. However, due to the cooling efficiency of the TEC refrigeration sheet, the power consumption required by the system will increase significantly, exacerbating the heat dissipation pressure. This phenomenon is particularly obvious when high power is injected, which can easily lead to excessive temperature difference between the cold and hot surfaces of the TEC, reduced cooling efficiency, and a vicious cycle. In severe cases, it will lead to temperature out of control.

[0003] In terms of clamping the working material, glue bonding, indium tin welding and other methods are currently used for fixing. In the curing process of these two methods, the colloid and solder often change in shape, causing the working material to be subjected to irregular mechanical stress, resulting in stress birefringence, causing the laser beam quality to deteriorate. When the laser is used on airborne, vehicle-mounted and other platforms, it often needs to withstand drastic changes in ambient temperature. Since the working material and the heat sink have different thermal expansion coefficients, there are hidden dangers such as debonding and open welding when the temperature changes drastically, which may cause the working material to rupture in severe cases.

[0004] Being able to achieve heat conduction of the pump module under high pump power injection conditions and to minimize or eliminate the thermal gradient difference of the laser working material and the mechanical stress caused by clamping has always been a technical problem in the design of high repetition rate and high energy air-cooled lasers, and is also one of the bottlenecks limiting its practical application. If the above problems can be solved and the structure can be made compact, it will be of great significance and practical value. Summary of the invention

[0005] The purpose of the present invention is to provide a conductive heat dissipation semiconductor side pump module structure, which is a semiconductor side pump device that relies on conductive heat dissipation. It can remove the waste heat generated by the pump module by conduction without active cooling devices such as TEC, thereby reducing the power consumption and heat dissipation pressure of the system; effectively reduce the radial thermal gradient of the working material, reduce the mechanical stress of the working material caused by clamping, and obtain uniform pump energy distribution and laser output with higher beam quality. It meets the use requirements of high repetition frequency and high energy pulse pumping under the condition of ambient temperature changes.

[0006] To achieve the above purpose, the technical solution of the present invention is implemented as follows: a conductive heat dissipation semiconductor side pumping module, including: a semiconductor chip array, a chip heat sink, a laser working material, a crystal pressure plate, a thermal conductive strip, a crystal heat sink, and a module bottom plate. It is characterized in that: the semiconductor chip is packaged in the form of an array on a metal chip heat sink, and the laser working material is pumped by end face or side coupling; the laser working material is a material used to achieve particle number inversion and generate stimulated radiation amplification of light; the clamping structure of the laser working material is from top to bottom: a crystal pressure plate, a working material, a thermal conductive strip, and a crystal heat sink, and the above parts are tightly pressed together by tightening the crystal pressure plate; the thermal conductive strip has a high thermal conductivity coefficient and a certain ductility, and can produce ductile deformation when subjected to external force. A groove array is processed at the position where the crystal heat sink contacts the thermal conductive strip, and the groove array can provide an extension space for the deformed thermal conductive strip.

[0007] The semiconductor chip array uses a single-side pumping method to irradiate the working material, and multiple groups of chip arrays can be used in combination to obtain higher injection power; or a double-side pumping method can be used to irradiate the working material to increase the pump power density per unit area of ​​the working material.

[0008] The packaging form of the semiconductor chip array is plane, semicircular or polygonal, and the pump light emitted by the packaged semiconductor chip array is of the same wavelength or different wavelengths with gradient distribution within a certain range.

[0009] The semiconductor chip works in a continuous pumping or pulse pumping mode. When the chip set is working, it can emit light at the same time or emit light alternately at a certain time frequency.

[0010] The cross-section of the heat conductive strip is circular, oval, square or polygonal, and is placed between the working substance and the metal heat sink to transfer the heat accumulated by the working substance during pumping operation while avoiding hard contact between the working substance and the heat sink.

[0011] The surface of the metal heat sink that the heat conducting strip contacts is processed with grooves, which can provide extension space for the shape change when the heat conducting strip is fixed.

[0012] The materials of the working substance include: Nd:YAG, Nd, Ce:YAG, Ho:YAG, Er:YAG, Er, Cr:YAG, Er, Yb:YAG, Yb:YAG, CTH:YAG, Nd:YLF, Ho:YLF, Pr:YLF, Cr:BeALO2, Nd:YVO4, Nd:KGW, Er:glass, Er, Yb:glass.

[0013] The shapes of the working material include: cuboid, cylinder, and prism.

[0014] The materials of the thermal conductive strip include: gold-tin alloy, indium-tin alloy, tin, indium, and thermal conductive silicone.

[0015] The metal heat sink material includes: oxygen-free copper, red copper, brass, and magnesium-aluminum alloy.

[0016] The positive effects of the present invention are: it can effectively reduce the mechanical stress problem generated by the working material in the clamping process of the high repetition rate and high energy air-cooled laser, reduce the radial thermal gradient difference generated by the working material during pumping, and avoid the deterioration of the beam quality of the output laser due to the above problems. At the same time, the pump module does not need to use TEC cooling, and can achieve thermal balance of temperature through conduction heat dissipation, greatly reducing the power consumption required by the system. It meets the use requirements of laser radar, laser ranging, laser induced breakdown spectroscopy detection and other directional lasers under the condition of ambient temperature changes. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A schematic diagram of a single-sided semiconductor side pumping structure provided in an embodiment of the present invention.

[0018] Figure 2 A schematic diagram of the structure of another double-sided semiconductor pump module provided in an embodiment of the present invention.

[0019] Figure 3 A partial schematic diagram of a thermally conductive strip and a crystal heat sink provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0020] The present invention is further described below in conjunction with the accompanying drawings and embodiments: It should be understood that these specific descriptions are only used to teach those skilled in the art how to implement the present invention, and are not intended to exhaust all feasible methods of the present invention, nor to limit the scope of the present invention. The embodiments include: a single-sided semiconductor pump module structure, a double-sided semiconductor pump module structure, and multiple single-sided or double-sided semiconductor pump module structures connected in series.

[0021] like Figure 1-3As shown, a conduction heat dissipation semiconductor side pump module includes: a semiconductor chip array 1, a chip heat sink 2, a laser working substance 3, a crystal pressure plate 4, a thermal strip 5, a crystal heat sink 6, and a module bottom plate 7; the characteristics are: the semiconductor chip is packaged in the form of an array on the metal chip heat sink 2, and the laser working substance 3 is pumped by end face or side coupling; the laser working substance 3 is a substance used to achieve particle number inversion and generate stimulated radiation amplification of light; the clamping structure of the laser working substance 3 is from top to bottom: a crystal pressure plate 4, a laser working substance 3, a thermal strip 5, and a crystal heat sink 6, and the above parts are tightly pressed together by tightening the crystal pressure plate; the thermal strip 5 has both a high thermal conductivity coefficient and a certain ductility, and can produce ductile deformation when subjected to external force. A groove array 8 is processed at the position where the crystal heat sink 6 contacts the thermal strip 5, and the groove array 8 can provide an extension space for the deformed thermal strip 5.

[0022] The semiconductor chip array 1 uses a single-side pumping method to irradiate the working material, and multiple groups of chip arrays can be used in combination to obtain higher injection power; or a double-side pumping method can be used to irradiate the working material to increase the pump power density per unit area of ​​the working material.

[0023] The packaging form of the semiconductor chip array 1 is plane, semicircular or polygonal, and the pump light emitted by the packaged semiconductor chip array is the same wavelength or different wavelengths with gradient distribution within a certain range.

[0024] The semiconductor chip works in a continuous pumping or pulse pumping mode. When the chip set is working, it can emit light at the same time or emit light alternately at a certain time frequency.

[0025] The cross section of the heat conducting strip 5 is circular, elliptical, square or polygonal, and is placed between the working substance and the crystal heat sink 6 to transfer the heat accumulated by the working substance during pumping operation while avoiding hard contact between the working substance and the heat sink.

[0026] The surface of the crystal heat sink 6 that the thermal conductive strip 5 contacts is processed with grooves, which can provide extension space for the shape change of the thermal conductive strip 5 when it is fixed.

[0027] The materials of the laser working material 3 include: Nd:YAG, Nd, Ce:YAG, Ho:YAG, Er:YAG, Er, Cr:YAG, Er, Yb:YAG, Yb:YAG, CTH:YAG, Nd:YLF, Ho:YLF, Pr:YLF, Cr:BeALO2, Nd:YVO4, Nd:KGW, Er:glass, Er, Yb:glass.

[0028] The shapes of the laser working material 3 include: a cuboid, a cylinder, and a prism.

[0029] The materials of the thermal conductive strip 5 include: gold-tin alloy, indium-tin alloy, tin, indium, and thermal conductive silicone.

[0030] The materials of the crystal heat sink 6 include: oxygen-free copper, red copper, brass, and magnesium-aluminum alloy.

[0031] like Figure 1 The structure of a single-sided semiconductor pump module is shown, including: a semiconductor chip array 1, a chip heat sink 2, a single-sided pump laser working substance 3-1, a single-sided pump crystal pressure plate 4-1, a heat conductive strip 5, a single-sided pump crystal heat sink 6-1, a single-sided pump module bottom plate 7-1, and a groove 8 in the crystal heat sink. The semiconductor chip array 1 can emit pump light of a specific wavelength under the drive of the pump current, and the wavelength of the pump light is near the absorption peak of the single-sided pump laser working substance 3-1. At present, the wavelength of the pump light emitted by conventional semiconductor chips will drift with the change of ambient temperature. Pump light with a wavelength far away from the absorption peak of the working substance will not be able to reverse the particles in the working substance, resulting in a decrease in the output laser power. Therefore, it is particularly important to export the waste heat generated by the pump source in time. The chip heat sink 2 and the single-sided pump module bottom plate 7-1 can be in an integrated form or in a split form for the convenience of chip packaging design. When a split design is adopted, on the one hand, it is necessary to ensure that there is a large contact area between the chip heat sink 2 and the module base plate 7-1, and on the other hand, thermal conductive silicone grease, indium foil, etc. can be used to fill the gap between the two to reduce thermal resistance. Figure 1 When a single-side pump structure is used, multiple pump modules can be combined to make the optical axis of the working material coincide. In order to ensure the uniformity of the working material pumping, it is preferred to use a combination of modules with opposite pumping directions to fill the power density difference in the working material away from the light-emitting point.

[0032] like Figure 2Another double-sided semiconductor pump module structure is shown, including a semiconductor chip array 1, a chip heat sink 2, a double-sided pump laser working material 3-2, a double-sided pump crystal pressure plate 4-2, a heat conductive strip 5, a double-sided pump crystal heat sink 6-2, a double-sided pump module bottom plate 7-2, and a groove 8 in the crystal heat sink. The semiconductor chip array 1 can emit pump light of a specific wavelength under the drive of the pump current, and the wavelength of the pump light is near the absorption peak of the double-sided pump laser working material 3-2. At present, the wavelength of the pump light emitted by conventional semiconductor chips will drift with the change of ambient temperature. Pump light with a wavelength far away from the absorption peak of the working material will not be able to reverse the particles in the working material, resulting in a decrease in the output laser power. Therefore, it is particularly important to export the waste heat generated by the pump source in time. The chip heat sink 2 and the double-sided pump module bottom plate 7-2 can be in an integrated form or in a split form for the convenience of chip packaging design. When a split design is adopted, on the one hand, a larger contact area must be ensured between the chip heat sink 2 and the module base plate 7 - 2 , and on the other hand, indium foil, thermal conductive silicone grease, etc. can be used to fill the gap between the two to reduce thermal resistance.

[0033] In order to achieve a good match between the wavelength emitted by the semiconductor chip array 1 and the absorption peak of the working substance 3 under different ambient temperatures, chip bars with different wavelengths can be packaged in the same array. The wavelength of the chip can be distributed in a gradient at both ends of the absorption peak of the working substance. When working at high temperature, the short-wave part below the peak will move toward the long-wave direction to maintain the overall pumping efficiency; conversely, under low temperature conditions, the long wave will also move toward the short wave direction to achieve compensation.

[0034] like Figure 2 When the double-side pump structure is used, the light-emitting points of the chip arrays on both sides are arranged at equal or non-equal heights. When the light-emitting points on the opposite sides are arranged in a non-equal height cross-arrangement, the pumping uniformity of the working material can be improved, and the chips can be prevented from irradiating each other and affecting their service life.

[0035] The crystal heat sink 6 and the pump module bottom plate 7 can be in an integrated form or a separate form. In the separate form, thermal conductive silicone grease, indium foil and other materials can also be used to fill the gap to reduce thermal resistance.

[0036] Figure 3 The figure shows a partial schematic diagram of the heat conducting strip and the crystal heat sink. The above pump structure is mainly used for the pumping, clamping and heat dissipation structure of the laser working material during high power pump injection.

[0037] like Figure 3As shown: grooves 8 are processed at the contact positions of the single-side pumped crystal heat sink 6-1 and the double-side pumped crystal heat sink 6-2 with the thermal conductive strip 5, and are arranged in an array. Since the material of the thermal conductive strip is relatively soft, when the single-side pumped crystal pressure plate 4-1 and the double-side pumped crystal pressure plate 4-2 press down the single-side pumped laser working material 3-1 and the double-side pumped laser working material 3-2, the thermal conductive strip 5 will be squeezed and deformed, and the groove 8 in the crystal heat sink will provide an extension space for the deformed thermal conductive strip. Due to the presence of the thermal conductive strip, the hard contact between the metal heat sink and the working material is avoided, reducing the irregular mechanical stress on the working material. At the same time, the thermal conductive strip 5 has a high thermal conductivity, which can timely conduct the waste heat generated in the working material to the crystal heat sink, reducing the radial thermal gradient in the working material. Indium foil or thermal conductive silicone grease is padded between the crystal pressure plate 4 and the working material 3 to compensate for the machining error between the working material and the crystal pressure plate and reduce thermal resistance.

[0038] The single-sided pump module base plate 7-1 and the double-sided pump module base plate 7-2 in this device need to be closely connected to the heat sink, constant temperature plate and other heat dissipation devices of the laser system, and the waste heat in the device is finally conducted to the outside world through conduction to maintain the stable operation of the system.

[0039] In summary, the method and device of the present invention can conduct heat generated by the pump module under high repetition frequency and high energy pumping conditions, greatly reducing the power consumption and heat dissipation pressure of the system. It can effectively reduce the radial thermal gradient of the working substance, reduce the mechanical stress of the working substance caused by clamping, and obtain uniform pump energy distribution, meeting the use requirements under ambient temperature changes.

[0040] The embodiments of the present invention are only used to illustrate the present invention and do not constitute a limitation on the scope of the claims. Other substantially equivalent substitutes in the art are all within the protection scope of the present invention.

Claims

1. A conductive heat dissipation semiconductor side pump module, comprising a semiconductor chip array, a chip heat sink, a laser working material, a crystal pressure plate, a thermal conductive strip, a crystal heat sink, and a module bottom plate; characterized in that: The semiconductor chip is packaged in the form of an array on a metal chip heat sink, and the laser working material is pumped by end or side coupling; the laser working material is a material used to achieve particle number inversion and produce stimulated radiation amplification of light; the clamping structure of the laser working material is from top to bottom: a crystal pressure plate, a working material, a thermal conductive strip, and a crystal heat sink, and the above parts are tightly pressed together by tightening the crystal pressure plate; the thermal conductive strip has a high thermal conductivity coefficient, and a groove array is processed at the position where the crystal heat sink contacts the thermal conductive strip, and the groove array can provide an extension space for the deformed thermal conductive strip.

2. A conductive heat dissipation semiconductor side pump module according to claim 1, characterized in that The semiconductor chip array uses a single-side pumping method to irradiate the working material, and multiple groups of chip arrays can be used in combination to obtain higher injection power; or a double-side pumping method can be used to irradiate the working material to increase the pump power density per unit area of ​​the working material.

3. A conductive heat dissipation semiconductor side pump module according to claim 1, characterized in that The packaging form of the semiconductor chip array is plane, semicircular or polygonal, and the pump light emitted by the packaged semiconductor chip array is of the same wavelength or different wavelengths with gradient distribution within a certain range.

4. The conductive heat dissipation semiconductor side pump module according to claim 1, characterized in that The semiconductor chip works in a continuous pumping or pulse pumping mode. When the chip set is working, it can emit light at the same time or emit light alternately at a certain time frequency.

5. The conductive heat dissipation semiconductor side pump module according to claim 1, characterized in that The cross section of the heat conducting strip is circular, oval, square or polygonal, and is placed between the working substance and the metal heat sink to transfer the heat accumulated by the working substance during pumping operation while avoiding hard contact between the working substance and the heat sink.

6. The conductive heat dissipation semiconductor side pump module according to claim 1, characterized in that The surface of the metal heat sink that the heat conducting strip contacts is processed with grooves, which can provide extension space for the shape change when the heat conducting strip is fixed.

7. The conductive heat dissipation semiconductor side pump module according to claim 1, characterized in that The material of the working material includes: Nd:YAG,Nd、Ce:YAG、Ho:YAG、Er:YAG、Er、Cr:YAG、Er、Yb:YAG、Yb:YAG、CTH:YAG、Nd:YLF、Ho:YLF、Pr:YLF、Cr:BeALO2 、Nd:YVO 4、 Nd:KGW, Er:glass, Er, Yb:glass.

8. The conductive heat dissipation semiconductor side pump module according to claim 1, characterized in that The shapes of the working material include: cuboid, cylinder, and prism.

9. The conductive heat dissipation semiconductor side pump module according to claim 1, characterized in that The materials of the thermal conductive strip include: gold-tin alloy, indium-tin alloy, tin, indium, and thermal conductive silicone.

10. The conductive heat dissipation semiconductor side pump module according to claim 1, characterized in that The metal heat sink material includes: oxygen-free copper, red copper, brass, and magnesium-aluminum alloy.

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