A heat dissipation structure applied to a high-power light emitting device

Abstract

The application discloses a heat dissipation structure applied to a high-power light emitting device, which comprises the following parts: a light emitting device emitting high-power laser light, wherein the light emitting device is a thin-layer type light emitting device, one side of the light emitting device is a light emitting surface, the other side is a cooling surface, the thickness of the light emitting device is A, the diameter of the light emitting area of the light emitting device is B, and A is less than B / 5; a cooling fluid layer flowing fast, which is arranged below the cooling surface and is used for absorbing and conducting the heat of the light emitting device, and the minimum distance between the cooling fluid layer and the cooling surface is C, and C is less than B / 5; and a supporting lens arranged on the light emitting surface and used for supporting and conducting light of the light emitting device, wherein the thickness of the supporting lens is D, and D is greater than 5A. The heat dissipation capacity of the high-power light emitting device can be improved, so that the power of the light emitting device is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of high-power optical technology, in particular to a heat dissipation structure applied to a high-power light emitting device. BACKGROUND

[0002] High-power light emitting devices are widely used in engineering lighting, laser weapons and other fields. High-power light is often accompanied by high-power waste heat. How to quickly remove the waste heat is an important technology in the field of high-power optics.

[0003] With the progress of technology, light emitting devices can be made thinner and thinner. For example, the OP-VECSEL reported in the high-power light pumped semiconductor vertical cavity surface emitting laser, the thickness of the semiconductor chip 1 is only a few microns. The latest report of the semiconductor thin film external cavity surface emitting laser MECSEL chip thickness can even be made below 1 micron. Their heat dissipation methods are shown in Figure 1 The technical method is: first, use high thermal conductivity material 2 (diamond, SiC, etc.) to diffuse heat energy at the heat source, then through copper heat sink, and then use water cooling structure 3 to take away the heat energy. This method of diffusing and taking away heat is more effective when the spot size is small. With the increase of laser power and the expansion of the gain area, the center of the spot is difficult to be taken away. With the accumulation of heat, the temperature in the center of the gain area is very high. The size of the light emitting area limits the light emitting power of the light emitting device. The spot size of OP-VECSEL is only about 1mm, and the highest power record is 106W. SUMMARY

[0004] The present application aims to solve at least one of the technical problems existing in the prior art. To this end, the present application provides a heat dissipation structure applied to a high-power light emitting device, which can improve the heat dissipation capacity of the high-power light emitting device, thereby achieving the purpose of improving the power of the light emitting device.

[0005] The technical solution adopted by the embodiment of the present application is: a heat dissipation structure applied to a high-power light emitting device, comprising: a light emitting device for surface emitting high-power laser, the light emitting device is a thin layer type light emitting device, one side of the light emitting device is a light emitting surface, the other side is a cooling surface, the thickness of the light emitting device is A, the diameter of the light emitting area of the light emitting device is B, A < B / 5; a cooling fluid layer flowing quickly, the cooling fluid layer is arranged below the cooling surface, used for absorbing and conducting the heat of the light emitting device, and the minimum distance between the cooling fluid layer and the cooling surface is C, C < B / 5; a support lens arranged on the light emitting surface for supporting and guiding light of the light emitting device, the thickness of the support lens is D, D > 5A.

[0006] The heat dissipation structure applied to the high-power light emitting device according to the embodiment of the present application has at least the following beneficial effects: on the basis of the thin-layer light emitting device, the thickness of the material of each layer of the cooling fluid layer is reduced to the waste heat generation area to reduce the heat path and improve the heat dissipation capacity of the device, the size of the light emitting area has little effect on the center temperature of the light emitting area, so that the light emitting device power can be improved by expanding the light emitting area, the support lens plays the dual role of light transmission and physical support for the thin-layer light emitting device, and the cooling fluid is responsible for absorbing waste heat and taking away the waste heat in the form of heat convection.

[0007] According to some embodiments of the present application, a functional layer is arranged between the cooling surface and the cooling fluid layer.

[0008] According to some embodiments of the present application, the functional layer is a protective functional layer.

[0009] According to some embodiments of the present application, the protective functional layer is a corrosion-resistant layer or an impact-resistant layer.

[0010] According to some embodiments of the present application, the corrosion-resistant layer is an anti-oxidation material.

[0011] According to some embodiments of the present application, the impact-resistant layer is a hard material layer.

[0012] According to some embodiments of the present application, the functional layer is a reflective layer.

[0013] According to some embodiments of the present application, the functional layer is a heat dissipation functional layer.

[0014] According to some embodiments of the present application, the heat dissipation functional layer is a porous material layer or a heat dissipation fin.

[0015] According to some embodiments of the present application, the cooling fluid layer comprises a support platform, the support platform is provided with an inlet flow channel and an outlet flow channel, the inlet flow channel and the outlet flow channel are arranged in an up-down manner, the outlet flow channel is attached to the cooling surface, and a flow channel hole is arranged between the inlet flow channel and the outlet flow channel, and the flow channel hole faces the cooling surface.

[0016] Additional aspects and advantages of the present application will be partially given in the following description, partially will become obvious from the following description, or will be understood by the practice of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0017] The above and / or additional aspects and advantages of the present application will become apparent and more readily appreciated from the following description, taken in conjunction with the following drawings, in which:

[0018] Figure 1 A diagram of a conventional OP-VECSEL heat dissipation structure;

[0019] Figure 2is a structural schematic diagram of the heat dissipation structure of the application applied to a high-power light emitting device;

[0020] Figure 3 is a way of increasing the flow rate of the cooling fluid of the application;

[0021] Figure 4 is a structural schematic diagram of the heat dissipation functional layer of the application;

[0022] Figure 5 is a structural schematic diagram of the heat dissipation functional layer of the application.

[0023] Reference signs:

[0024] semiconductor chip 1, high-thermal-conductivity material 2, cooling fluid 3;

[0025] light emitting device 100, cooling fluid layer 200, support table 210, inflow channel 221, outflow channel 222, flow channel hole 223, support lens 300, functional layer 400. DETAILED DESCRIPTION

[0026] The embodiments of the application are described in detail below, and examples of the embodiments are shown in the drawings, wherein the same or similar reference signs represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary and are only used to explain the application, and cannot be understood as a limitation of the application.

[0027] In the description of the application, it should be understood that the orientation description, such as the orientation or position relationship indicated by up, down, front, back, left, right, etc. is based on the orientation or position relationship shown in the drawings, and is only for the convenience of describing the application and simplifying the description, and therefore cannot be understood as a limitation of the application.

[0028] In the description of the application, the meaning of several is one or more, and the meaning of multiple is more than two. Greater than, less than, more than, etc. are understood as not including the number, and above, below, etc. are understood as including the number. If the first and the second are described, it is only for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features or the sequence of indicated technical features.

[0029] In the description of the application, unless otherwise explicitly limited, the words such as setting, installing, connecting, etc. should be understood in a broad sense, and the person skilled in the art can reasonably determine the specific meaning of the above words in the application in combination with the specific content of the technical solution.

[0030] In addition, the technical solutions among various embodiments of the present application can be combined with each other, but the combination of the technical solutions should be considered not to exist and not within the protection scope of the present application when the combination of the technical solutions appears contradictory or unachievable on the basis that the combination of the technical solutions can be realized by the ordinary skilled in the art.

[0031] The application applied to the heat dissipation structure of high-power light emitting device as shown in figure 2, comprising: light emitting device emitting high-power laser, the light emitting device is thin layer type light emitting device, one side of the light emitting device is light emitting surface, the other side is cooling surface, the thickness of the light emitting device is A, the diameter of the light emitting area of the light emitting device is B, A < B / 5, further preferably A < B / 10;

[0032] Fast flowing cooling fluid layer, the cooling fluid layer is arranged below the cooling surface, used for absorbing and conducting the heat of the light emitting device, and the minimum distance between the cooling fluid layer and the cooling surface is C, C < B / 5, further preferably C < B / 10;

[0033] Supporting lens, arranged on the light emitting surface for supporting and light guiding the light emitting device, the thickness of the supporting lens is D, D > 5A.

[0034] The present application is based on one-dimensional heat dissipation theory, by reducing the heat distance between heat source and cooling liquid flow, the heat dissipation performance of the light emitting device 100 is improved, so as to improve the light emitting power of high-power light emitting device.

[0035] Specifically, on the thin layer type light emitting device 100, if the generated waste heat can be taken away in the direction perpendicular to the surface of the thin layer, without considering the diffusion of the waste heat in the direction parallel to the plane, that is, the one-dimensional heat dissipation ability is achieved. In order to facilitate discussion, only the vertical heat diffusion is considered here (note: if the heat diffusion in the plane direction is considered, the heat dissipation effect will be better), when the diameter of the light emitting area of the light emitting device 100 is much larger than the distance between the light emitting device 100 and the cooling fluid, it can be considered to achieve one-dimensional heat dissipation condition, and the device heat dissipation ability can be calculated by one-dimensional heat dissipation theory.

[0036] When the heat dissipation structure has one-dimensional heat dissipation ability, the area size of the working area of the light emitting device 100 no longer has too great influence on the temperature of the working area, that is, the light emitting power of the light emitting device 100 can be improved by expanding the area of the working area.

[0037] Under the condition of one-dimensional heat dissipation, the heat energy with intensity q, passing through a layer of medium with thickness d and thermal conductivity k, the temperature difference ΔT between the two surfaces before and after the medium under the condition of heat balance satisfies the following formula:

[0038]

[0039] The The heat path of the heat conducting medium is defined as the heat path of the heat conducting medium, the intensity of the waste heat generated in the working area of the light emitting device 100 when working is q, the heat energy is conducted through the light emitting device 100 in the direction perpendicular to the surface, and is conducted to the surface of the cooling fluid layer 200 through the functional layer 400. The heat conduction passes through n layers of materials, in turn, the first to the nth layer, the thickness of the i-th layer of material is d i , the thermal conductivity is k i , the temperature difference ΔT between the light emitting surface of the device and the surface of the cooling liquid satisfies the following formula:

[0040]

[0041] The heat path of the i-th layer of material is The total heat path of the first layer to the i-th layer of material is to improve the heat dissipation capacity of the light emitting device 100, that is, to reduce the total heat path of the waste heat through all the materials. On the one hand, higher thermal conductivity materials can be used, and on the other hand, the number of medium materials can be reduced or the thickness of the medium materials can be reduced to reduce the total heat path.

[0042] The feature of the present application is to improve the heat dissipation capacity of the device by reducing the thickness of each layer of material between the waste heat generating area and the cooling fluid on the basis of the thin layer type light emitting device 100. That is, under the premise of one-dimensional heat dissipation theory, the total heat path of the waste heat through the material is reduced as much as possible, and the temperature difference between the heat source of the light emitting device 100 and the cooling fluid layer 200 is reduced. Under the condition of one-dimensional heat dissipation, the size of the light emitting area of the light emitting device 100 has little effect on the center temperature of the light emitting area, and the power of the light emitting device can be improved by expanding the light emitting area.

[0043] Specifically, as shown in Figure 2 , the thin layer type light emitting device 100 is a thin layer type light emitting device which emits light by means of optical excitation or electrical excitation. The wavelength of the emitted light wave can be any one or more of deep ultraviolet to far infrared wavelengths. The cooling fluid layer 200 is only separated by the necessary functional layer 300 close to the light emitting device 100, and the waste heat generated in the working process of the light emitting device 100 is taken away through the cooling fluid layer 200. The support lens 300 is a light wave conducting medium transparent to the emitted light wavelength, which is closely attached to the light emitting device 100. The light emitted by the light emitting device 100 is emitted through the support lens 300, and the support lens 300 also plays a physical support role for the light emitting device 100.

[0044] Because the cooling fluid layer 200 generates significant pressure during rapid flow, and the light-emitting device 100 is a thin-layer type made of very thin material, without the support lens 300, the light-emitting device 100 would be easily broken or damaged under pressure. By providing the support lens 200, the light-emitting device 100 is given physical support, preventing it from being broken by the pressure generated during the movement of the cooling fluid layer 200.

[0045] In some embodiments of the present invention, a functional layer 400 is provided between the cooling surface and the cooling fluid layer 200. The cooling fluid layer 200 and the cooling surface can be in direct contact, or a sufficiently thin functional layer 400 can be added in between to realize certain specific functions of the light-emitting device 100.

[0046] In a further embodiment of the present invention, the functional layer 400 is a protective functional layer. In order to achieve better heat dissipation, the coolant in the cooling fluid layer 200 has an extremely fast flow rate, which can reach 1000 meters per second. At such a high speed, the coolant will place high demands on the strength of the light-emitting device 100. However, the light-emitting device 100 is easily damaged due to the limitations of its own structure. The light-emitting device 100 is protected by setting a protective functional layer.

[0047] Specifically, the protective functional layer is either an anti-corrosion layer or an impact-resistant layer. The anti-corrosion layer can prevent the coolant from eroding and corroding the light-emitting device 100, while the impact-resistant layer can reduce the direct impact damage to the light-emitting device 100 caused by high flow rates.

[0048] In a further embodiment of the present invention, the anti-corrosion layer is an anti-oxidation layer, such as silicon dioxide or aluminum oxide, to prevent the light emitter 100 from being oxidized by dissolved oxygen in the cooling liquid through direct contact.

[0049] In a further embodiment of the present invention, the impact-resistant layer is a hard material layer, such as a diamond layer or a silicon carbide layer, which has the ability to resist impact and also has good thermal conductivity.

[0050] In some embodiments of the present invention, the functional layer is a reflective layer, which is used to reflect light emitted from the cooling surface.

[0051] like Figure 4 and Figure 5 As shown, in some embodiments of the present invention, the functional layer 400 is a heat dissipation functional layer. A heat dissipation functional layer is provided to further improve the heat dissipation capability of the light-emitting device 100.

[0052] In a further embodiment of the present invention, the heat dissipation functional layer is a porous material layer or heat dissipation fins. Although the thickness of the porous material layer is not much smaller than the diameter of the working area of ​​the light-emitting device 100, the cooling fluid can freely pass through the porous material, and the distance between the cooling fluid and the light-emitting device 100 is much smaller than the diameter of the working area of ​​the light-emitting device 100. As a functional layer, the porous material layer increases the heat exchange area between the cooling fluid and the light-emitting device 100, thereby improving the heat dissipation performance. Alternatively, the contact area between the heat dissipation surface and the coolant can also be increased by setting heat dissipation fins.

[0053] like Figure 3 As shown, in some embodiments of the present invention, the cooling fluid layer 200 includes a support platform 210 and a liquid flow channel disposed within the support platform 210. The liquid flow channel includes an inlet channel 221 and an outlet channel 222, which are arranged vertically. The outlet channel 222 is in contact with the cooling surface. A flow channel hole 223 is provided between the inlet channel 221 and the outlet channel 222, and the flow channel hole 223 faces the cooling surface.

[0054] When the power density at the heat source is high, the amount of heat that can be carried away by the cooling fluid at a normal flow rate when it comes into contact with the cooling surface of the light-emitting device 100 is limited. To improve the heat dissipation capacity of the device, the flow rate of the water at the contact surface can be increased by using an impact-type water flow, or by welding porous materials onto the cooling surface to increase the heat exchange area.

[0055] Specifically, high-pressure fluid is injected at the inlet channel 221, forming a high-speed fluid at the channel hole 223 that impacts the cooling surface of the light-emitting device 100, using the high flow rate of the cooling fluid to remove heat from the light-emitting device 100. The supporting lens 300 bears the strong impact force of the cooling fluid on the light-emitting device 100.

[0056] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0057] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A heat dissipating structure applied to a high-power light emitting device, characterized by, The application relates to a surface-emitting high-power laser light-emitting device, which is a thin-layer light-emitting device, one side of the light-emitting device is a light-emitting surface, the other side is a cooling surface, the thickness of the light-emitting device is A, the diameter of the light-emitting area of the light-emitting device is B, A < B / 5; a fast-flowing cooling fluid layer is arranged below the cooling surface, is used for absorbing and conducting the heat of the light-emitting device, and the minimum distance between the cooling fluid layer and the cooling surface is C, C < B / 5; the cooling fluid layer comprises a supporting table, the supporting table is provided with an inflow channel and an outflow channel, the inflow channel and the outflow channel are arranged in a top-and-bottom mode, the outflow channel is attached to the cooling surface, a flow channel hole is arranged between the inflow channel and the outflow channel, the flow channel hole faces the cooling surface, a functional layer is arranged between the cooling surface and the cooling fluid layer; a supporting lens is arranged on the light-emitting surface and is used for supporting and light guiding the light-emitting device, the thickness of the supporting lens is D, D > 5A, the supporting lens is used for providing physical support for the light-emitting device and avoiding the light-emitting device from being broken by the pressure generated in the movement of the cooling fluid layer. The functional layer is a protective functional layer. The protective functional layer is a corrosion-resistant layer or an impact-resistant layer. The corrosion-resistant layer is an anti-oxidation material.

2. The heat dissipation structure for high power light emitting devices according to claim 1, wherein: The impact-resistant layer is a hard material layer.

3. The heat dissipation structure for high power light emitting devices according to claim 2, wherein: The functional layer is a reflecting layer.

4. The heat dissipation structure for high power light emitting devices according to claim 3, wherein: The functional layer is a heat-dissipating functional layer.

5. The heat dissipation structure for high power light emitting devices according to claim 3, wherein: The heat-dissipating functional layer is a porous material layer or a heat-dissipating fin.

6. The heat dissipation structure for high power light emitting devices according to claim 1, wherein: ​ 7. The heat dissipation structure for high power light emitting devices according to claim 1, wherein: ​ 8. The heat dissipation structure for high power light emitting devices according to claim 7, wherein: ​

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