Laser illumination module

Abstract

The laser lighting module comprises a laser diode, a first collimating lens, a multi-face reflector, a fluorescent powder piece, a second collimating lens and a reflector array which are sequentially arranged along a light path, a plurality of reflecting faces are arranged on the side, corresponding to the fluorescent powder piece, of the multi-face reflector, and a light through hole is formed in the middle of the multi-face reflector. A laser beam emitted by the laser diode sequentially passes through the first collimating lens and the light through hole and then is projected to the fluorescent powder piece, and light excited by the fluorescent powder piece is reflected by the multi-face reflector, sequentially passes through the second collimating lens and the reflector array and then is emitted. Through the arrangement of the reflective fluorescent powder sheet and the multi-surface reflector comprising a plurality of reflecting surfaces, when a laser beam is projected onto the fluorescent powder sheet, generated white light is converged on the second collimating lens after being reflected by the plurality of reflecting surfaces, and is emitted to the reflector array to be projected out after being collimated by the second collimating lens; by adopting the reflective fluorescent powder sheet, the power of the laser diode can be improved, and the brightness and the spatial distribution uniformity of emergent light are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor lighting, and particularly to a laser lighting module. Background Art

[0002] The lighting function of lamps can be mainly divided into the main lighting function of floodlighting and the functional lighting function of decorative lighting. With the increasing richness of people's spiritual and cultural life, people's cultural and entertainment programs are also constantly enriched. Accordingly, people's requirements for the functional lighting function of decorative lighting of lamps are getting higher and higher. At present, many star projection lamps are provided on the market, and people can create a starry sky atmosphere through star projection lamps.

[0003] Existing star projection lamps usually generate scattered white light by laser exciting a phosphor, and then reflect an irregular star point effect through an optical reflector. However, existing star projection lamps all adopt a transmissive laser light source, such as the star projection lamp in the patent publication number CN208222182U. However, although the solution of the star projection lamp adopting a transmissive laser light source is simple, it needs to rely on a transparent glass material, such as a sapphire wafer, to help the phosphor material dissipate heat, which will lead to poor heat dissipation effect of the phosphor material. Therefore, the brightness of the transmissive laser light source is usually not high. Secondly, since the blue laser is directly transmitted through the phosphor material, this results in uneven spatial distribution of the blue light. Therefore, the transmissive laser light source also has the problem of uneven spatial color distribution. Summary of the Invention

[0004] The present invention aims at the problems existing in the prior art, and provides a laser lighting module with high brightness and good spatial distribution uniformity.

[0005] To solve the above technical problems, the technical solution of the present invention is: a laser lighting module, comprising a laser diode, a first collimating lens, a multi-faceted reflector, a phosphor sheet, a second collimating lens and a mirror array arranged in sequence along the optical path. The side of the multi-faceted reflector corresponding to the phosphor sheet is provided with a plurality of reflecting surfaces, and a light passing hole is provided in the middle of the multi-faceted reflector. The laser beam emitted by the laser diode is projected onto the phosphor sheet after passing through the first collimating lens and the light passing hole in sequence, and the light excited by the phosphor sheet is reflected by the multi-faceted reflector and then passes through the second collimating lens and the mirror array in sequence and then exits.

[0006] Further, the multi-faceted reflector is in a bowl shape, and the inner side includes a plurality of trapezoidal reflectors arranged in sequence along the circumference of the light passing hole.

[0007] Further, the multi-faceted reflector is an injection molded part, and the plurality of reflecting surfaces are aluminized reflecting surfaces.

[0008] Further, the plurality of reflecting surfaces are planes or curved surfaces of the same or different sizes.

[0009] Further, the first collimating lens is a biconvex glass lens.

[0010] Further, the first collimating lens is composed of a plurality of spherical lenses.

[0011] Further, a diffusing sheet is also provided behind the laser diode along the optical path.

[0012] Further, the phosphor sheet is a fluorescent ceramic sheet and is attached to a heat-conducting substrate.

[0013] Further, a reflective layer is provided between the fluorescent ceramic sheet and the heat-conducting substrate.

[0014] The laser illumination module provided by the present invention includes a laser diode, a first collimating lens, a multi-faceted reflector, a phosphor sheet, a second collimating lens, and a mirror array arranged in sequence along the optical path. A plurality of reflecting surfaces are provided on one side of the multi-faceted reflector corresponding to the phosphor sheet, and a light passing hole is provided in the middle of the multi-faceted reflector. The laser beam emitted by the laser diode passes through the first collimating lens and the light passing hole in sequence and then is projected onto the phosphor sheet. The light excited by the phosphor sheet passes through the multi-faceted reflector and is reflected and then passes through the second collimating lens and the mirror array in sequence and then exits. By providing a reflective phosphor sheet and a multi-faceted reflector including a plurality of reflecting surfaces, and different reflecting surfaces are all arranged facing the phosphor sheet. When the blue laser beam is projected onto the phosphor sheet, white light is generated by being excited by the phosphor therein. The generated white light is reflected by the plurality of reflecting surfaces on the multi-faceted reflector and then converges onto the second collimating lens. After being collimated by it, it exits to the mirror array and is projected out, forming a starry sky projection effect. Using a reflective phosphor sheet can increase the power of the laser diode, or reduce the size of the laser focusing spot, increase the laser power density after focusing, and improve the brightness and spatial distribution uniformity of the emitted light. Description of the Drawings

[0015] Figure 1 is a schematic structural diagram of a specific embodiment of the laser illumination module of the present invention;

[0016] Figure 2 is a schematic optical path structural diagram of a specific embodiment of the laser illumination module of the present invention;

[0017] Figure 3 is a schematic structural diagram of a specific embodiment of the multi-faceted reflector of the present invention.

[0018] As shown in the figure: 10, laser diode; 20, first collimating lens; 30, multi-faceted reflector; 310, light passing hole; 320, reflecting surface; 40, phosphor sheet; 50, second collimating lens; 60, mirror array; 70, heat-conducting substrate; 80, mounting bracket. Detailed implementation mode

[0019] The present invention will be described in detail below with reference to the accompanying drawings:

[0020] As Figures 1-3 shown, the present invention provides a laser illumination module, which includes a laser diode 10, a first collimating lens 20, a multi-faceted reflector 30, a phosphor sheet 40, a second collimating lens 50 and a mirror array 60 arranged in sequence along the optical path. On the side of the multi-faceted reflector 30 corresponding to the phosphor sheet 40, there are several reflecting surfaces 320, and a light passing hole 310 is provided in the middle of the multi-faceted reflector 30. The laser beam emitted by the laser diode 10 passes through the first collimating lens 20 and the light passing hole 310 in sequence and then projects onto the phosphor sheet 40. The light excited by the phosphor sheet 40 passes through the multi-faceted reflector 30 After reflection, it passes through the second collimating lens 50 and the mirror array 60 in sequence and then exits. Specifically, the multi-faceted reflector 30 includes a plurality of reflecting surfaces 320, and different reflecting surfaces 320 are all arranged facing the phosphor sheet 40. There are obvious boundaries between different reflecting surfaces 320. In addition, a light passing hole 310 is provided at the center of the multi-faceted reflector 30. The purpose of this light passing hole 310 is to allow the incident laser beam to pass through. In this embodiment, the laser diode 10 emits a blue laser beam, and the phosphor sheet 40 is a reflective phosphor sheet. When the blue laser beam projects onto the phosphor sheet 40, white light is generated by being excited by the phosphor therein. The generated white light passes through the multi-faceted reflector 30. After being reflected by the plurality of reflecting surfaces 320 on the body, it converges on the second collimating lens 50, and after being collimated by it, it exits to the mirror array 60 and is projected out, forming a starry sky projection effect. Using the reflective phosphor sheet 40 can increase the power of the laser diode 10, or reduce the size of the laser focus spot, increase the laser power density after focusing, and increase the brightness of the emitted light.

[0021] As Figure 1 shown, during installation, the laser diode 10 and the first collimating lens 20 can be fixed together on the mounting bracket 80, or the first collimating lens 20 and the multi-faceted reflector 30 can be fixed together, which can reduce the installation components of the first collimating lens 20, save costs, and be stable and reliable. The laser diode 10 can adopt a TO package form, and this package structure can provide good heat dissipation and protect the laser chip inside from adverse conditions.

[0022] In principle, the multi-faceted reflector 30 can image the light-emitting surface on the phosphor sheet 40. Since the multi-faceted reflector 30 includes a plurality of reflecting surfaces 320, and each reflecting surface 320 can independently image the light source surface, a plurality of light source image points can be formed. These light source image points are collimated by the second collimating lens 50 and then projected through the mirror array 60, forming more spots. This effect is similar to a starry sky, so it is called a star projection lamp. The number of projected light points can be simply calculated as follows: Assume there are M reflecting surfaces 320 on the multi-faceted reflector 30, so M light source image points can be formed. Then assume there are N small mirrors on the mirror array 60 after the second collimating lens 50. In an ideal situation, M*N light points can be finally projected.

[0023] As Figure 3 shown, the multi-faceted reflector 30 is bowl-shaped, and the inner side includes a number of trapezoidal mirrors, which are arranged in sequence along the circumferential direction of the light passing hole 310. Specifically, the sizes of the trapezoidal mirrors can be the same or different, and they are attached to the inner side of the multi-faceted reflector 30 along the outer circumference of the light passing hole 310. They can be arranged regularly or irregularly, and can be set in one or more circles.

[0024] Preferably, the multi-faceted reflector 30 can be made of an injection-molded part, and a number of reflecting surfaces 320 are plated on the surface. Preferably, PC plastic can be used as the base material to make the polyhedron by injection molding, and the reflecting surface is formed by aluminizing or other metals on the surface. This manufacturing method has a low cost. In addition, when making the polyhedron by the injection molding process, the plurality of reflecting surfaces are no longer limited to planes, but can be designed as curved surfaces, and different reflecting surfaces can be designed with different curvature radii. In this way, each reflecting surface can image the light source as an enlarged or reduced image, and the sizes of the image points formed by different reflecting surfaces are also different. And a number of reflecting surfaces 320 in the multi-faceted reflector 30 can be plated in one or more circles, and can be arranged regularly or irregularly.

[0025] Preferably, the phosphor sheet 40 is a fluorescent ceramic sheet, which is attached to the heat-conducting substrate 70. A reflective layer is provided between the fluorescent ceramic sheet and the heat-conducting substrate 70. Specifically, the heat-conducting substrate 70 can be made of metal materials such as copper and aluminum, or ceramic materials with high thermal conductivity such as aluminum nitride and silicon carbide. These materials have very high thermal conductivity, which can greatly improve the heat dissipation performance of the fluorescent material. Therefore, the laser power that the reflective phosphor can withstand is much higher than that of the transmissive phosphor, thereby further increasing the laser power density after focusing and improving the brightness of the laser light source. To further improve the efficiency of the laser light source, a reflective layer needs to be provided between the fluorescent material and the heat-conducting substrate. The function of the reflective layer is to reflect the back-emitted light of the phosphor sheet to the front surface of the phosphor sheet, and finally emit from the front surface of the phosphor sheet. The reflective layer can be a highly reflective mirror aluminum plate, or a reflective film can be directly deposited on the surface of the phosphor sheet, including metal aluminum or silver, or a Bragg reflective layer formed by a multi-layer dielectric film.

[0026] Preferably, the first collimating lens 20 can be an aspherical lens, such as a biconvex glass lens. The laser output from the laser diode usually has a small divergence angle. For example, the divergence angle of the fast axis direction of the blue light diode is usually less than 40 degrees. Therefore, an aspherical lens can meet the requirements of light convergence. Of course, in order to achieve the focusing of the laser beam with only one collimating lens, the refractive index of the selected aspherical lens needs to be greater than 1.5, and the numerical aperture also needs to be greater than 0.5. The first collimating lens 20 can also use spherical lenses, and in this case, multiple lenses are needed to achieve an ideal focusing effect.

[0027] Preferably, the laser illumination module further includes a diffuser sheet provided behind the laser diode 10, which can further make the focused laser spot be a uniform circle. Here, the diffuser sheet refers to a glass sheet that can uniformly diffuse the laser beam. Since common semiconductor laser diodes have fast and slow axes, the beam divergence angles of the fast and slow axes are different, and the light source positions are also different. Therefore, using a common collimating lens usually can only obtain an elliptical or even strip-shaped converging spot, and cannot obtain a circular focused spot. The shape of the laser focused spot determines the shape of the light-emitting surface of the light source. In most applications, a circular light-emitting surface is required. To make the focused laser beam as close to a circle as possible, a diffuser sheet for homogenizing the laser beam can be added to the laser optical path. The diffuser sheet can be provided in front of the first collimating lens 20 or behind the first collimating lens 20.

[0028] Although the embodiments of the present invention are described in the specification, these embodiments are only for reference and should not limit the protection scope of the present invention. All omissions, substitutions, and changes made within the scope of the purpose of the present invention should be included in the protection scope of the present invention.

Claims

1. A laser illumination module, characterized in that, It includes a laser diode, a first collimating lens, a multi-faceted reflector, a phosphor sheet, a second collimating lens, and a mirror array arranged in sequence along the optical path. On one side of the multi-faceted reflector corresponding to the phosphor sheet, there are a number of reflecting surfaces, and a light passing hole is provided in the middle of the multi-faceted reflector. The laser beam emitted by the laser diode passes through the first collimating lens and the light passing hole in sequence and then is projected onto the phosphor sheet. The light excited by the phosphor sheet is reflected by the multi-faceted reflector and then passes through the second collimating lens and the mirror array in sequence and then exits.

2. The laser illumination module according to claim 1, wherein, The multi-faceted reflector is bowl-shaped, and the inner side includes a number of trapezoidal reflectors arranged in sequence along the circumference of the light passing hole.

3. The laser illumination module according to claim 1, wherein, The multi-faceted reflector is an injection molded part, and the number of reflecting surfaces are aluminized reflecting surfaces.

4. The laser illumination module according to claim 3, wherein The number of reflecting surfaces are plane or curved surfaces of the same / different sizes.

5. The laser illumination module according to claim 1, wherein The first collimating lens is a double convex glass lens.

6. The laser illumination module according to claim 1, characterized in that The first collimating lens is composed of multiple spherical lenses.

7. The laser illumination module according to claim 1, wherein It further includes a diffuser sheet provided behind the laser diode along the optical path.

8. The laser illumination module according to claim 1, wherein, The phosphor sheet is a fluorescent ceramic sheet, which is attached to a heat conducting substrate.

9. The laser illumination module according to claim 8, wherein, A reflective layer is provided between the fluorescent ceramic sheet and the heat conducting substrate.

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