Wavelength conversion wheel and white laser light source system

Abstract

The utility model relates to a wavelength conversion wheel and a white laser light source system, and the wavelength conversion wheel comprises a metal base, a transparent substrate, an optical film layer and a fluorescent layer which are sequentially arranged from bottom to top, the white laser light source system comprises the required wavelength conversion wheel, a laser diode module, a condensing lens, a diffusion sheet, a packaging cover plate, a motor, a motor fixing base, a main body base, a red copper base, a circuit board fixing base and a shell. Blue light emitted by the laser diode module is condensed by the condensing lens, then enters the diffusion sheet for dodging and then enters the wavelength conversion wheel, the motor rotates to drive the wavelength conversion wheel to rotate, and the blue light is converted into white light through the wavelength conversion wheel. The utility model can be applied to the fields of laser illumination, laser projection, optical fiber light sources and the like, and has the advantages of small light-emitting area, high energy density, small volume and the like.

Description

Technical Field

[0001] The utility model relates to the fields of laser lighting, laser projection, fiber cold light source, etc., and specifically relates to a wavelength conversion wheel and a white laser light source system. Background Technique

[0002] With the continuous progress of technology, the requirements for light sources are also constantly increasing, especially the pursuit of a smaller area of the light-emitting point and a higher brightness of the light source. In lighting optical design, the étendue is a key factor, which refers to the integral of the area through which the light beam passes and the solid angle occupied by the light beam. In the optical design process, only when the étendue of the optical element is well matched can the utilization rate of light energy be guaranteed. In practical applications, such as lighting, projection, or fiber cold light source, etc., the étendue of the core components is fixed. For example, the DMD chip in laser projection and the optical fiber in fiber cold light source, the light-passing surface size and receiving angle of these core components are determined. Therefore, the étendue of the light source is limited by the étendue of these core devices and cannot exceed these limited values. In order to improve the brightness of the light source, it is necessary to start from the light source itself, that is, to increase the power density of the light source.

[0003] White laser technology (light source technology based on laser-excited fluorescence) provides an effective solution. This technology uses the monochromatic light generated by a laser diode to excite a fluorescent material, thereby generating white light. The étendue of white laser is small and the energy density is high, which is suitable for various optical designs. Compared with the mainstream LED light source, under the same étendue, white laser can provide a higher luminous flux, and the area of the light-emitting point is smaller under the same energy, thus making the optical system design more compact.

[0004] The core of white laser technology lies in the laser diode and the wavelength conversion film. Since the laser with too high power may break through the wavelength conversion film, based on the requirements in applications of small light-emitting points and high-brightness light sources, a method needs to be found to enable the wavelength conversion film to withstand the laser irradiation with high power density. Content of the Utility Model

[0005] In order to solve the above problems, the core of the utility model is to use the rotation of the motor to drive the rotation of the wavelength conversion wheel to improve the bearing capacity of the fluorescent layer on the wavelength conversion wheel. On the other hand, in cooperation with the optical design, a white laser light source system with a smaller light-emitting point area and a higher power density is achieved.

[0006] A wavelength conversion wheel includes a metal base, a transparent substrate, an optical film layer, and a fluorescent layer which are sequentially arranged from bottom to top; when the fluorescent wheel works, the laser enters the transparent substrate through the annular light-passing port of the metal base, then passes through the optical film layer and enters the fluorescent layer, and part of the blue light excites the fluorescent layer to generate yellow light, and the yellow light is mixed with the unabsorbed blue light to generate white light.

[0007] A white laser light source system, comprising a laser diode module, a condenser lens, a diffuser, a packaging cover plate, the wavelength conversion wheel as required above, a motor, a motor fixing base, a main body base, a copper base, a circuit board fixing base, and a housing. The blue light emitted by the laser diode module is collected by the condenser lens and incident on the diffuser for light homogenization, and then incident on the wavelength conversion wheel. The motor rotates to drive the wavelength conversion wheel to rotate, and the blue light is converted into white light by the wavelength conversion wheel.

[0008] Further, the central hole of the metal base is sleeved on the central shaft of the motor, and the metal base is fixed on the motor by glue.

[0009] Further, the material of the metal base can be a metal with good heat dissipation such as copper, aluminum, or aluminum alloy. There is an impeller structure at the bottom of the metal base, and the motor rotates to drive the impeller structure of the metal base to rotate to dissipate the heat generated by the fluorescent layer.

[0010] Further, the metal base is disc-shaped, and an annular groove is opened near the outer periphery of the disc. The outer ring is connected to the main body by several ribs.

[0011] Further, the thickness of the metal base is 1 - 4 mm, and the diameter is 30 - 100 mm. The size of the metal base is determined comprehensively according to the load of the motor and the area required for heat dissipation of the fluorescent layer.

[0012] Further, the transmittance of the optical film layer for light with a wavelength of 430 nm - 470 nm is greater than 95%, and the reflectance for light with a wavelength of 500 nm - 700 nm is greater than 95%, that is, the laser emitted by the laser diode is transmitted, and the light generated by reflecting the laser to excite the fluorescent layer is ensured to exit from the outer surface of the fluorescent layer.

[0013] Further, the fluorescent layer is made of one or more fluorescent powders of yellow, red, or green, and its thickness is between 0.01 mm and 0.10 mm.

[0014] Further, the laser diode module is composed of one or two or more identical laser diodes, and its emission wavelength is between 430 nm - 470 nm. The number of laser diodes depends on the required light flux and the bearing capacity of the fluorescent layer.

[0015] Further, the aperture of the condenser lens is between 5 mm and 60 mm, and the focal length is between 4 mm and 100 mm. The light emitted by the laser diode module is condensed. In most cases, a specially designed aspherical lens is used to reduce spherical aberration and focus the laser to a smaller size.

[0016] Further, the diffusion angle of the diffusion sheet is between 0.5° and 10°, and the thickness is between 0.3 mm and 2.0 mm. The incident laser is homogenized. The diffusion sheet is divided into a matte surface and a glass surface. The matte surface faces the condenser lens. The angle and thickness of the diffusion sheet are determined according to the spot size on the wavelength conversion wheel. The smaller the required spot, the smaller the diffusion angle.

[0017] Further, the rotational speed of the motor is 5300 - 23000 rpm. The higher the laser power of the laser diode module, the faster the rotational speed of the motor. At the same time, the influence of vibration factors needs to be comprehensively considered.

[0018] Further, on the circuit board fixing base, a driving circuit board is fixed. When the power supply is controlled to work, the motor rotates first, and then the laser diode is lit. When the light source is turned off, the laser diode is turned off first, and then the motor stops rotating. When the power of the laser diode is very high, after the laser diode is turned off, the motor will delay for a period of time before stopping rotating to prevent damage to the fluorescent layer of the wavelength conversion wheel.

[0019] Further, the motor is fixed to the motor fixing base by screws, and the motor fixing base is fixed to the main body base by screws. The motor fixing base has three vertical slots, and the distance from the wavelength conversion wheel to the diffusion sheet can be finely adjusted thereby to ensure the consistency of the size of the light-emitting point.

[0020] Further, the diffusion sheet is fixed on the light-passing port of the main body base. When the rotational speed of the motor is too fast, in order to prevent the impeller structure from hitting the diffusion sheet due to the vibration of the wavelength conversion wheel, the distance between the control diffusion sheet and the wavelength conversion wheel needs to be designed.

[0021] Further, the laser diode module is fixed to the copper base by screws and thermal conductive silicone grease. There are four through holes on the copper base, which can be connected to heat dissipation modules with different performances, and a suitable radiator or cooling fan can be found for use according to the requirements of the use environment.

[0022] The utility model has the following beneficial effects:

[0023] (1) Small light-emitting area: The rotation of the motor drives the rotation of the wavelength conversion wheel, equivalently increasing the area and improving the bearing capacity of the fluorescent layer, so that the light-emitting point can be made smaller. (2) High luminous flux: The white laser technology is adopted, and the luminous flux is higher when the light-emitting point is the same size. (3) Small volume: Under the same optical performance conditions as the led light source, the optical device can be made smaller and the power can be made smaller, greatly reducing the volume of the light source. Description of the Drawings

[0024] Figure 1Schematic cross-sectional view of the white laser light source structure with 8 laser diodes, where 1, laser diode module; 2, condenser lens; 3, diffuser; 4, encapsulation cover plate; 5, wavelength conversion wheel; 6, motor; 7, motor fixing base;

[0025] 8, main body base; 9, copper base; 10, circuit board fixing base; 11, housing.

[0026] Figure 2 Schematic bottom view of the wavelength conversion wheel.

[0027] Figure 3 Schematic front view of the wavelength conversion wheel, where 501, metal base; 502, transparent substrate; 503, optical film layer; 504, fluorescent layer; the thickness of each layer is for easy viewing of the figure and is not the actual thickness ratio.

[0028] Figure 4 Schematic cross-sectional view of the white laser light source structure with 24 laser diodes, where 1, laser diode module; 2, condenser lens; 3, diffuser; 4, encapsulation cover plate; 5, wavelength conversion wheel; 6, motor; 7, motor fixing base; 8, main body base; 9, copper base; 10, circuit board fixing base; 11, housing. Specific implementation mode

[0029] In order to more clearly illustrate the present invention, the present invention will be further described below in conjunction with preferred embodiments and the accompanying drawings. Those skilled in the art should understand that the specific content described below is illustrative rather than restrictive, and should not be used to limit the protection scope of the present invention.

[0030] Example 1: Refer to Figure 2 and Figure 3, which is a schematic structural diagram of a wavelength conversion wheel with a motor. In this embodiment, the 501 metal base of the entire wavelength conversion wheel is made of aluminum alloy 6063, with a diameter of 52 mm, a width of the annular groove of 2 mm, and an impeller structure at the bottom. It is driven by a motor to rotate at high speed, driving the metal base to rotate at high speed to dissipate the heat generated by the fluorescent layer. The 502 transparent substrate is connected to the metal base through a thermal conductive glue. The transparent substrate is a sapphire substrate, and an optical film layer 503 is plated on the transparent substrate. The light with a wavelength passing through of 430 nm - 470 nm has a transmittance greater than 95%, and the light with a wavelength reflected of 500 nm - 700 nm has a reflectivity greater than 95%, improving the light flux. The 504 fluorescent layer is directly sintered on the optical film layer of the transparent substrate. Part of the blue light will excite the phosphor on the fluorescent layer to generate yellow light, and the yellow light is mixed with the unabsorbed blue light to form white laser. In order to make the light-emitting point of the entire wavelength conversion wheel smaller and the output power higher, it is necessary to improve the bearing capacity of the fluorescent layer. The motor drives the wavelength conversion wheel to rotate at high speed, which is equivalent to increasing the irradiation area of the fluorescent layer per unit time, and is connected to the metal base, and its heat dissipation performance is much better than materials such as glass.

[0031] Refer to Figure 1 , which is a white laser light source using the wavelength conversion wheel of Embodiment 1. The 1 laser diode module is fixed on the 9 copper base. There are four through holes with a diameter of 3 mm left at the edge of the base, through which a radiator can be installed to ensure the heat dissipation of the laser diode. The number of laser diodes in the laser diode module is 8, with a light power of 44 w. The aperture of the 2 condenser lens is 16 mm, and the focal length is 28 mm. The blue light emitted by the laser diode is focused onto the 3 diffuser. The angle of the diffuser is 1.5°, and the thickness is 0.7 mm. The diffuser is fixed on the 8 main base through uv glue and ultraviolet lamp irradiation. The condenser lens is fixed in the groove of the main base through a retaining ring. The diffuser equalizes the incident laser and then irradiates it onto the wavelength conversion wheel. The rotational speed of the motor is 10,800 rpm, and it is fixed on the 7 motor fixing base through screws. The motor fixing base is fixed to the main base through screws. Using an imaging luminance meter to test, the size of the light-emitting point is 0.3 mm x 0.4 mm. There are several air outlets on the 11 housing, through which hot air can be blown out to dissipate the heat on the wavelength conversion wheel. A filter is installed inside the air outlet, which can filter out most of the dust and prevent the dust from falling on the wavelength conversion wheel. There is a circuit board on the 10 circuit board fixing base, which controls the motor to rotate first and then lights up the light source. When the power is turned off, the laser diode module is turned off first, and then the motor rotation is stopped. The light flux is 4,574 lumens after being tested by an integrating sphere.

[0032] Embodiment 2; Refer to Figure 4, which is a schematic cross-sectional structure diagram of a white laser light source with 24 laser diodes. The number of laser diodes is 24, the optical power is 112w, the diameter of the condenser lens used is 51.5mm, the focal length is 50mm, the diffusion angle of the diffusion sheet is 5°, the thickness is 0.5mm, the diffusion sheet is attached to the diffusion sheet base, the motor speed is 16500rpm, and there is a 3mm spacing between the wavelength conversion wheel and the diffusion sheet during design to prevent the impeller structure from colliding with the diffusion sheet due to vibration when the wavelength conversion wheel rotates at high speed. After testing with an imaging luminance meter, the size of the light-emitting point is 1.25mm x 1.5mm, and after testing with an integrating sphere, the luminous flux reaches 15640 lumens.

[0033] Those skilled in the art should understand that the embodiments of the present invention described above and shown in the drawings are only examples and do not limit the present invention. The object of the present invention has been fully and effectively achieved. The functions and structural principles of the present invention have been demonstrated and explained in the embodiments, and without departing from the said principles, any deformation or modification of the embodiments of the present invention is possible.

Claims

1. A wavelength conversion wheel, characterized in that: It includes a metal base, a transparent substrate, an optical film layer, and a fluorescent layer arranged in sequence from bottom to top; when the fluorescent wheel is working, the laser is incident on the transparent substrate through the light opening of the metal base, and then passes through the optical film layer and is incident on the fluorescent layer. Part of the blue light excites the fluorescent layer to produce yellow light, and the yellow light is mixed with the unabsorbed blue light to produce white light.

2. A wavelength conversion wheel according to claim 1, characterized in that: The metal base is in the shape of a disc, and an annular groove is provided near the outer circumference of the disc, and the outer ring is connected to the main body through ribs.

3. The wavelength conversion wheel according to claim 1, characterized in that: The thickness of the metal base is 1-4 mm, and the diameter is 30-100 mm.

4. The wavelength conversion wheel according to claim 1, characterized in that: The bottom surface of the metal base is provided with an impeller structure, and the heat generated by the fluorescent layer is dissipated by the rotation of the impeller structure.

5. The wavelength conversion wheel according to claim 1, characterized in that: The transmittance of the optical film layer to light with a wavelength of 430nm to 470nm is greater than 95%, and the reflectivity to light with a wavelength of 500nm to 700nm is greater than 95%.

6. The wavelength conversion wheel according to claim 1, characterized in that: The fluorescent layer is made of one or more fluorescent powders of yellow, red and green, and its thickness is between 0.01mm and 0.10mm.

7. A white laser light source system, characterized in that: It comprises a wavelength conversion wheel as described in any one of claims 1 to 6, a laser diode module, a focusing lens, a diffuser, a packaging cover, a motor, a motor fixing base, a main body base, a copper base, a circuit fixing board base, and a shell: the blue light emitted by the laser diode module is focused by the focusing lens and incident on the diffuser for uniform light, and then incident on the wavelength conversion wheel. The rotation of the motor drives the wavelength conversion wheel to rotate, and the blue light is converted into white light through the wavelength conversion wheel.

8. The white laser light source system according to claim 7, characterized in that: The laser diode module is composed of one or two or more identical laser diodes, and the emission wavelength thereof is between 430nm and 470nm.

9. The white laser light source system according to claim 7, characterized in that: The diffusion angle of the diffusion sheet is between 0.5° and 10°, and the thickness is between 0.3mm and 2.0mm.

10. The white laser light source system according to claim 7, characterized in that: The motor speed is 5300-23000rpm.

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