A white light source with active heat dissipation

Abstract

The present invention discloses a white light source with active heat dissipation, belonging to the field of lighting sources. The light source comprises: a thermoelectric cooler, which comprises, from bottom to top, a lower ceramic substrate, a middle ceramic substrate, and an upper ceramic substrate, and further comprises thermoelectric particles filled between the lower and middle ceramic substrates, and between the lower and upper ceramic substrates, with the upper ceramic substrate being located outside the middle ceramic substrate; a wavelength conversion unit, which is fixedly mounted on the upper surface of the upper ceramic substrate and forms a cavity with the upper and middle ceramic substrates; a light-emitting unit, which is fixedly mounted on the upper surface of the middle ceramic substrate and located within the cavity, and is configured to emit blue light and excite the wavelength conversion unit to generate white light; a reflective unit, which is configured to reflect the excitation blue light of the light-emitting unit; and a thermoelectric cooler for simultaneously actively dissipating heat from the wavelength conversion unit and the light-emitting unit. This simultaneously solves the problem of excessive temperature of the fluorescent conversion material and the excitation chip.

Description

Technical Field

[0001] The present invention belongs to the field of lighting sources, and more particularly, relates to a white light source with active heat dissipation. Background Art

[0002] Against the backdrop of the current global energy shortage, semiconductor solid-state lighting, with its advantages of high luminous efficiency, low energy consumption, long life, and environmental friendliness, has led to the continuous improvement of the country's energy conservation and environmental protection capabilities. For semiconductor white light sources based on fluorescence conversion, device temperature affects their luminescence performance. For fluorescence conversion white light sources, part of the chip's input electrical energy is converted into heat. In addition, the fluorescence conversion material also undergoes non-radiative transitions and generates heat. Heat accumulation causes the light source temperature to rise, affecting not only the chip's luminescence performance, but also the luminous efficiency of the fluorescence conversion material, adversely affecting the performance and reliability of the semiconductor white light source. Therefore, heat dissipation is one of the technical bottlenecks in the development of high-power semiconductor white light sources.

[0003] To address this issue, researchers have designed semiconductor lighting packages from two perspectives: passive and active heat dissipation. Passive heat dissipation relies on the thermal conductivity of the packaging materials and structures. Given its limitations, high-power semiconductor lighting primarily utilizes active heat dissipation, such as forced air cooling, circulating liquid cooling, heat pipes, and thermoelectric cooling. However, most active heat dissipation methods only dissipate the heat of the excitation chip or excitation module of the white light source, without considering the heat dissipation of the fluorescent conversion material. This is especially true for high-power density white laser light sources, where heat accumulation in the fluorescent conversion material is a more serious problem. Therefore, it is necessary to comprehensively consider the heat dissipation of both the excitation chip and the fluorescent conversion material to meet the application requirements of high-brightness semiconductor white light sources. Summary of the Invention

[0004] In response to the defects of the existing technology and the need for improvement, the present invention provides a white light source with active heat dissipation, which aims to simultaneously solve the problem of excessive temperature of the fluorescent conversion material and the excitation chip and the resulting failure of traditional organic packaging at high temperatures, thereby improving the performance and reliability of semiconductor white light source packaging.

[0005] To achieve the above-mentioned objectives, the present invention provides a white light source with active heat dissipation, comprising: a thermoelectric cooler, which comprises, from bottom to top, a lower ceramic substrate, a middle ceramic substrate and an upper ceramic substrate, and also comprises thermoelectric particles filled between the lower ceramic substrate and the middle ceramic substrate and between the lower ceramic substrate and the upper ceramic substrate, and the upper ceramic substrate is located on the outside of the middle ceramic substrate; a wavelength conversion unit, which is fixedly arranged on the upper surface of the upper ceramic substrate and forms a cavity with the upper ceramic substrate and the middle ceramic substrate; a light-emitting unit, which is fixedly arranged on the upper surface of the middle ceramic substrate and is located in the cavity, and is used to emit blue light and excite the wavelength conversion unit to form white light; the thermoelectric cooler is used to actively dissipate heat for the wavelength conversion unit and the light-emitting unit at the same time.

[0006] Furthermore, it further includes: a reflection unit, which is fixedly arranged on the upper surface of the middle ceramic substrate and surrounds the light-emitting unit, and is used to reflect the blue light emitted by the light-emitting unit.

[0007] Furthermore, the inner surface of the reflection unit is a diffuse reflection layer or a specular reflection layer, and the reflectivity is greater than 90%.

[0008] Furthermore, the invention further comprises: an adhesive layer located between the wavelength conversion unit and the upper ceramic substrate, for fixing the wavelength conversion unit to the upper surface of the upper ceramic substrate.

[0009] Furthermore, the material of the bonding layer is metal solder or high thermal conductivity adhesive, and the thermal conductivity coefficient is greater than 30 W / (m·K).

[0010] Furthermore, the light emitting unit is a blue laser or a blue LED, a conductive through hole is provided in the middle ceramic substrate, and the light emitting unit is electrically connected to the outside through the conductive through hole.

[0011] Furthermore, the wavelength conversion unit is made of fluorescent glass, fluorescent ceramic or fluorescent single crystal, and is used to form white light under the excitation of the blue light generated by the blue laser or blue LED.

[0012] Furthermore, a height difference d between the middle ceramic substrate and the upper ceramic substrate is 8 mm to 16 mm, a height h of the white light source is 10 mm to 20 mm, and d<h.

[0013] Furthermore, the material of the ceramic substrate in the thermoelectric cooler is aluminum oxide or aluminum nitride, and the thermoelectric particles are welded to the ceramic substrate through a copper layer on the ceramic substrate.

[0014] In general, the above technical solutions conceived by the present invention can achieve the following beneficial effects: the structure of the thermoelectric cooler is designed to obtain a special-shaped thermoelectric cooler with pits that is in contact with both the wavelength conversion unit and the light-emitting unit, so that the light-emitting unit (excitation chip) and the wavelength conversion unit (fluorescence conversion material) are simultaneously dissipated through the thermoelectric cooler, while solving the heat dissipation problem of the excitation chip and the fluorescence conversion material, improving the luminescence performance of the chip and the luminescence efficiency of the fluorescence conversion material, and greatly improving the performance and reliability of the white light source, thereby meeting the application requirements of high-brightness semiconductor white light sources; in addition, the design of the reflection unit reduces the loss of light, further improving the performance of the white light source, so that the white light source has the advantages of high power, high brightness, good heat dissipation and low light loss. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A schematic structural diagram of a white light source with active heat dissipation provided by an embodiment of the present invention;

[0016] Figure 2 A schematic structural diagram of a light-emitting unit provided in one embodiment of the present invention;

[0017] Figure 3 This is a structural diagram of a light-emitting unit provided in another embodiment of the present invention.

[0018] Throughout the drawings, the same reference numerals are used to denote the same elements or structures, wherein:

[0019] 1 is a thermoelectric cooler, 11 is a lower ceramic substrate, 12 is a middle ceramic substrate, 13 is an upper ceramic substrate, 14 is a thermoelectric particle, 2 is a wavelength conversion unit, 3 is a light-emitting unit, 4 is a reflection unit, and 5 is an adhesive layer. DETAILED DESCRIPTION

[0020] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely for the purpose of explaining the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

[0021] In the present invention, the terms "first", "second", etc. (if any) in the present invention and the drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0022] Figure 1 This is a schematic diagram of the structure of a white light source with active heat dissipation provided by an embodiment of the present invention. Figure 1 , combined with Figure 2-Figure 3, the white light source with active heat dissipation in this embodiment is described in detail.

[0023] See Figure 1 The active heat dissipation white light source includes a thermoelectric cooler 1, a wavelength conversion unit 2, and a light-emitting unit 3. The thermoelectric cooler 1 includes, from bottom to top, a lower ceramic substrate 11, a middle ceramic substrate 12, and an upper ceramic substrate 13. It also includes thermoelectric particles 14 filled between the lower ceramic substrate 11 and the middle ceramic substrate 12, and between the lower ceramic substrate 11 and the upper ceramic substrate 13. The upper ceramic substrate 13 is located outside the middle ceramic substrate 12 to form a special-shaped thermoelectric cooler 1 with pits.

[0024] Wavelength conversion unit 2 is fixedly mounted on the upper surface of upper ceramic substrate 13 and forms a cavity with upper ceramic substrate 13 and middle ceramic substrate 12. Light-emitting unit 3 is fixedly mounted on the upper surface of middle ceramic substrate 12, within the cavity formed by wavelength conversion unit 2, upper ceramic substrate 13, and middle ceramic substrate 12. It emits blue light and excites wavelength conversion unit 2 to produce white light. Thermoelectric cooler 1 can actively dissipate heat from both wavelength conversion unit 2 and light-emitting unit 3 simultaneously.

[0025] According to an embodiment of the present invention, the active heat dissipation white light source further includes a reflective unit 4. This reflective unit 4 is fixedly mounted on the upper surface of the middle ceramic substrate 12 and surrounds the light-emitting unit 3. It is configured to reflect the blue light emitted by the light-emitting unit 3, reducing light loss and further improving the performance of the white light source. The inner surface of the reflective unit 4 is a diffuse or specular reflective layer with a reflectivity greater than 90%.

[0026] According to an embodiment of the present invention, the active heat dissipation white light source further includes an adhesive layer 5. This adhesive layer 5 is located between the wavelength conversion unit 2 and the upper ceramic substrate 13 and is used to securely bond the wavelength conversion unit 2 to the upper surface of the upper ceramic substrate 13. Adhesive layer 5 is made of metal solder or highly thermally conductive adhesive with a thermal conductivity greater than 30 W / (m·K). This ensures that the required bonding strength is met while effectively conducting heat generated by the wavelength conversion unit 2 under high-power blue light excitation.

[0027] The ceramic substrates (lower ceramic substrate 11, middle ceramic substrate 12 and upper ceramic substrate 13) in the thermoelectric cooler 1 are made of aluminum oxide or aluminum nitride. The thermoelectric particles 14 are soldered to the ceramic substrates via a copper layer on the ceramic substrates.

[0028] According to an embodiment of the present invention, conductive vias are provided in the middle ceramic substrate 12, through which the light-emitting unit 3 is electrically connected to the outside. The light-emitting unit 3 can be secured to the surface of the middle ceramic substrate 12 via a highly thermally conductive adhesive layer. Preferably, the height difference d between the middle ceramic substrate 12 and the upper ceramic substrate 13 is 8 mm to 16 mm, and the total height h of the white light source is 10 mm to 20 mm, where d < h.

[0029] Light-emitting unit 3 is a blue light-emitting diode (LED) or a blue laser. When light-emitting unit 3 is a blue laser or blue LED, wavelength conversion unit 2 is made of fluorescent glass, fluorescent ceramic, or fluorescent single crystal. It is used to generate white light under the excitation of the blue light generated by the blue laser or blue LED, and its visible light transmittance is greater than 60%.

[0030] In one embodiment of the present invention, the light emitting unit 3 is a blue light LED. Figure 2 As shown. When the light-emitting unit 3 is a blue LED, the ceramic substrate in the thermoelectric cooler 1 is made of alumina. The wavelength conversion unit 2 is made of, for example, fluorescent glass containing YAG yellow phosphor, with a visible light transmittance of 75%. The inner surface of the reflective unit 4 is a diffuse reflective surface, made of, for example, barium sulfate, with a reflectivity of 95%. The adhesive layer 5 is made of, for example, a high thermal conductivity adhesive with a thermal conductivity coefficient of 35 W / (m·K). The total height h of the white light source is, for example, 10 mm, and the height difference d between the middle ceramic substrate 12 and the upper ceramic substrate 13 is 8 mm.

[0031] In another embodiment of the present invention, the light emitting unit 3 is a blue laser, such as Figure 3 As shown. When the light-emitting unit 3 is a blue laser, the ceramic substrate in the thermoelectric cooler 1 is made of aluminum nitride; the wavelength conversion unit 2 is made of, for example, fluorescent glass containing YAG yellow phosphor, with a visible light transmittance of 70%; the inner surface of the reflective unit 4 is a mirror-like reflective layer, made of, for example, a silver film with a reflectivity of 95%; the adhesive layer 5 is made of, for example, metal solder with a thermal conductivity of 100 W / (m·K). The total height h of the white light source is, for example, 20 mm, and the height difference d between the middle ceramic substrate 12 and the upper ceramic substrate 13 is 16 mm.

[0032] The actively heat-dissipating white light source in the embodiment of the present invention utilizes the thermoelectric cooling effect to simultaneously achieve active heat dissipation of the light-emitting unit and the fluorescent conversion material, meeting the heat dissipation requirements of the package in high-power laser lighting and LED lighting, so that the white light source has the advantages of high power, high brightness, good heat dissipation and low light loss.

[0033] It will be easily understood by those skilled in the art that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A white light source with active heat dissipation, characterized in that: include: A thermoelectric cooler (1) comprises, from bottom to top, a lower ceramic substrate (11), a middle ceramic substrate (12), and an upper ceramic substrate (13), and further comprises thermoelectric particles (14) filled between the lower ceramic substrate (11) and the middle ceramic substrate (12), and between the lower ceramic substrate (11) and the upper ceramic substrate (13), wherein the upper ceramic substrate (13) is located outside the middle ceramic substrate (12); a wavelength conversion unit (2) fixedly arranged on the upper surface of the upper ceramic substrate (13) and forming a cavity with the upper ceramic substrate (13) and the middle ceramic substrate (12); A light-emitting unit (3) is fixedly arranged on the upper surface of the middle ceramic substrate (12), located in the cavity, and configured to emit blue light and excite the wavelength conversion unit (2) to form white light; The thermoelectric cooler (1) is used to actively dissipate heat for the wavelength conversion unit (2) and the light-emitting unit (3) simultaneously.

2. The active heat dissipation white light source according to claim 1, characterized in that: Also includes: A reflection unit (4) is fixedly arranged on the upper surface of the middle ceramic substrate (12) and surrounds the light-emitting unit (3), and is used for reflecting the blue light emitted by the light-emitting unit (3).

3. The active heat dissipation white light source according to claim 2, characterized in that: The inner surface of the reflection unit (4) is a diffuse reflection layer or a mirror reflection layer, and the reflectivity is greater than 90%.

4. The active heat dissipation white light source according to claim 1, wherein: Also includes: An adhesive layer (5) is located between the wavelength conversion unit (2) and the upper ceramic substrate (13), and is used to fix the wavelength conversion unit (2) to the upper surface of the upper ceramic substrate (13).

5. The active heat dissipation white light source according to claim 4, characterized in that: The material of the bonding layer (5) is metal solder or high thermal conductivity glue, and the thermal conductivity coefficient is greater than 30W / (m·K).

6. The active heat dissipation white light source according to claim 1, wherein: The light-emitting unit (3) is a blue laser or a blue LED, a conductive through-hole is provided in the middle ceramic substrate (12), and the light-emitting unit (3) is electrically connected to the outside through the conductive through-hole.

7. The active heat dissipation white light source according to claim 6, characterized in that: The wavelength conversion unit (2) is made of fluorescent glass, fluorescent ceramic or fluorescent single crystal and is used to form white light under the excitation of the blue light generated by the blue laser or blue LED.

8. The white light source with active heat dissipation according to any one of claims 1 to 7, characterized in that: The height difference d between the middle ceramic substrate (12) and the upper ceramic substrate (13) is 8 mm to 16 mm, the height h of the white light source is 10 mm to 20 mm, and d<h.

9. The white light source with active heat dissipation according to any one of claims 1 to 7, characterized in that: The material of the ceramic substrate in the thermoelectric cooler (1) is aluminum oxide or aluminum nitride, and the thermoelectric particles (14) are welded to the ceramic substrate through a copper layer on the ceramic substrate.

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