Lighting device

Abstract

This invention provides an illumination device including a laser source, a wavelength conversion element, and a diffusion element. The laser source emits laser light; the wavelength conversion element converts at least a portion of the received laser light into fluorescence; the diffusion element is located between the laser source and the wavelength conversion element, and includes a first scattering region and a second scattering region surrounding the first scattering region. The diffusion angle of the first scattering region is smaller than the diffusion angle of the second scattering region. The laser light is scattered by the first and second scattering regions before entering the wavelength conversion element. The illumination device provided by this invention, by setting a diffusion element including a first scattering region and a second scattering region surrounding the first scattering region, and wherein the diffusion angle of the first scattering region is smaller than the diffusion angle of the second scattering region, reduces the yellowish glare at the edge of the emitted light spot without affecting the central illuminance of the emitted light spot, thereby improving image quality.

Description

Technical Field

[0001] This invention relates to the field of optical technology, and more specifically, to an illumination device. Background Technology

[0002] Lasers possess characteristics such as high brightness, good monochromaticity, strong directionality, and high coherence. Ultra-high brightness light sources can be obtained using laser-excited phosphor technology (remote excitation fluorescence technology). Laser-excited phosphor technology involves focusing a laser beam onto a phosphor layer, forming a light-emitting spot. The phosphor is excited and produces high-brightness light. Typically, a blue laser excites yellow phosphor, and the resulting yellow light mixes with the remaining blue light to form white light.

[0003] Since the surface of a fluorescent device is typically diffuse reflective, the size of the remaining blue light spot is roughly the same as the incident laser spot. However, the excited fluorescence has a divergence angle of 4π. A portion of the fluorescence at this angle is directly transmitted out of the fluorescent device, while another portion is reflected and scattered multiple times before being transmitted out again, thus enlarging the fluorescence spot. Furthermore, after the laser enters the fluorescent device, it is continuously absorbed, reflected, and scattered. When the laser encounters phosphor, it is converted into fluorescence, resulting in a larger fluorescence spot than the laser spot. Consequently, the diffusion of the remaining laser spot is smaller than that of the fluorescence spot. Therefore, a ring of yellow light often appears at the edge of the mixed white light, severely affecting the imaging quality of the laser-fluorescent light source. Summary of the Invention

[0004] The purpose of this invention is to provide a lighting device to solve the above-mentioned problems.

[0005] The embodiments of the present invention achieve the above objectives through the following technical solutions.

[0006] In a first aspect, the present invention provides an illumination device, comprising a laser source, a wavelength conversion element, and a diffusion element. The laser source is used to emit laser light; the wavelength conversion element is used to convert at least a portion of the received laser light into fluorescence; the diffusion element is located between the laser source and the wavelength conversion element, and the diffusion element includes a first scattering region and a second scattering region surrounding the first scattering region. The diffusion angle of the first scattering region is smaller than the diffusion angle of the second scattering region, and the laser light is incident on the wavelength conversion element after being scattered by the first scattering region and the second scattering region.

[0007] In one embodiment, the laser light passes through the entire first scattering region and at least a portion of the second scattering region before being incident on the wavelength conversion element.

[0008] In one embodiment, the center of the first scattering region and the center of the second scattering region coincide, and the center of the laser spot on the diffusion element coincides with the center of the first scattering region.

[0009] In one embodiment, the first scattering region and the second scattering region have different diffusion angles on the X-axis and Y-axis, wherein the X-axis and Y-axis are perpendicular to each other and both the X-axis and Y-axis are parallel to the surface of the diffusion element.

[0010] In one implementation, the diffusion angle of the first scattering region is a constant, and the diffusion angle of the second scattering region is also a constant.

[0011] In one implementation, the diffusion angle of the first scattering region is 0°.

[0012] In one embodiment, the diffusion element has a through hole, and the first scattering region is the through hole.

[0013] In one embodiment, from the center to the edge of the diffusion element, the diffusion angle of the first scattering region gradually increases, and the diffusion angle of the second scattering region also gradually increases. The maximum value of the diffusion angle of the first scattering region is less than or equal to the minimum value of the diffusion angle of the second scattering region.

[0014] In one embodiment, the lighting device further includes a first optical system disposed between the diffusion element and the wavelength conversion element, wherein the laser light scattered by the diffusion element passes through the first optical system and is incident on the wavelength conversion element.

[0015] In one embodiment, the lighting device further includes a second optical system disposed between the laser source and the diffusion element, wherein the laser emitted from the laser source is incident on the diffusion element via the second optical system.

[0016] In one embodiment, the first optical system includes a prism, which has an incident surface, a total reflection surface, and a refractive surface. The angle between the incident surface and the total reflection surface is an acute angle, and the angle between the incident surface and the refractive surface is also an acute angle. The laser emitted from the laser source is incident on the prism from the incident surface, and after being reflected by the total reflection surface, it is emitted from the refractive surface to the wavelength conversion element. The second optical system includes a converging lens disposed on the light-emitting side of the laser source, which is used to converge the laser emitted from the laser source. In one embodiment, the first optical system includes a first optical path guiding element and a collecting lens, and the second optical system includes a converging lens and a second optical path guiding element. The converging lens is disposed on the light-emitting side of the laser source and is used to converge the laser emitted from the laser source. The second optical path guiding element is located between the converging lens and the diffuser element and is used to guide the laser emitted from the converging lens to the diffuser element. The first optical path guiding element and the collecting lens are sequentially located between the diffuser element and the wavelength conversion element. The first optical path guiding element is used to reflect the laser emitted from the diffuser element and transmit the fluorescence emitted from the wavelength conversion element. The laser reflected by the first optical path guiding element is incident on the wavelength conversion element after passing through the collecting lens. The fluorescence emitted from the wavelength conversion element is collected by the collecting lens and then emitted through the first optical path guiding element.

[0017] In one embodiment, the first optical system includes a first optical path guiding element and a collecting lens, and the second optical system includes a converging lens and a second optical path guiding element. The converging lens is disposed on the light-emitting side of the laser source and is used to converge the laser emitted from the laser source. The second optical path guiding element and the first optical path guiding element are sequentially located between the converging lens and the diffuser. The second optical path guiding element is used to guide the laser emitted from the converging lens to the first optical path guiding element. The first optical path guiding element is used to reflect the laser emitted from the second optical path guiding element and transmit the fluorescence emitted from the wavelength conversion element. The collecting lens is located between the diffuser and the wavelength conversion element. The laser reflected by the first optical path guiding element passes sequentially through the diffuser and the collecting lens and then enters the wavelength conversion element. The fluorescence emitted from the wavelength conversion element passes sequentially through the collecting lens and the diffuser and then passes through the first optical path guiding element and exits.

[0018] In one embodiment, the first optical system includes a first optical path guiding element and a collecting lens, and the second optical system includes a converging lens and a second optical path guiding element. The converging lens is disposed on the light-emitting side of the laser source and is used to converge the laser emitted from the laser source. The second optical path guiding element is located between the converging lens and the diffuser element and is used to guide the laser emitted from the converging lens to the diffuser element. The first optical path guiding element is disposed on the side of the diffuser element away from the second optical path guiding element and is used to reflect the laser emitted from the second optical path guiding element and transmit the fluorescence emitted from the wavelength conversion element. The collecting lens is located between the diffuser element and the wavelength conversion element. The first optical path guiding element reflects the laser scattered by the diffuser element and, after passing through the collecting lens, enters the wavelength conversion element. The fluorescence emitted from the wavelength conversion element is collected by the collecting lens and then passes through the diffuser element and the first optical path guiding element in sequence before being emitted.

[0019] Compared to existing technologies, the lighting device provided by this invention, by setting a diffusion element, includes a first scattering area and a second scattering area surrounding the first scattering area, and the diffusion angle of the first scattering area is smaller than that of the second scattering area. After the laser is scattered by the first and second scattering areas, due to the smaller diffusion angle of the first scattering area, the central region of the laser diffuses less or not at all, and the laser in the edge region diffuses to the central region, thereby reducing or eliminating the intensity drop in the central region of the emitted laser spot, allowing the light source to illuminate a longer distance. Due to the larger diffusion angle of the second scattering area, the edge region of the laser spot can be expanded, allowing the laser spot on the wavelength conversion element to cover the fluorescent spot, thereby improving the color uniformity of the light emitted from the wavelength conversion element.

[0020] These or other aspects of the invention will become more apparent from the following description of the embodiments. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is an optical path diagram of the lighting device provided in an embodiment of the present invention.

[0023] Figure 2 This is a schematic diagram of the structure of the diffusion element of the lighting device provided in the embodiment of the present invention.

[0024] Figure 3 It is the laser intensity distribution in the central region of the wavelength conversion element when there is no diffusion element.

[0025] Figure 4 It is the laser intensity distribution at the edge region of the wavelength conversion element when there is no diffusion element.

[0026] Figure 5 It refers to the laser intensity distribution in the central region of the wavelength conversion element when using a diffusion element.

[0027] Figure 6 It refers to the laser intensity distribution in the edge region of the wavelength conversion element when using a diffusion element.

[0028] Figure 7 This is a schematic diagram of the diffusion angle of the first type of diffusion element in the lighting device provided in the embodiment of the present invention.

[0029] Figure 8 This is a schematic diagram of the diffusion angle of the second type of diffusion element in the lighting device provided in the embodiment of the present invention.

[0030] Figure 9 This is a schematic diagram of the diffusion angle of the third type of diffusion element in the lighting device provided in the embodiment of the present invention.

[0031] Figure 10 This is a schematic diagram of the diffusion angle of the fourth type of diffusion element in the lighting device provided in the embodiments of the present invention.

[0032] Figure 11 This is a schematic diagram of the diffusion angle of the fifth type of diffusion element in the lighting device provided in this embodiment of the invention.

[0033] Figure 12 This is the optical path diagram of the first type of lighting device provided in the embodiments of the present invention.

[0034] Figure 13 This is the optical path diagram of the second type of lighting device provided in the embodiments of the present invention.

[0035] Figure 14 This is the optical path diagram of the third type of lighting device provided in the embodiments of the present invention.

[0036] Figure 15 This is the optical path diagram of the fourth type of lighting device provided in the embodiments of the present invention. Detailed Implementation

[0037] To facilitate understanding of the embodiments of the present invention, a more complete description of the embodiments will be given below with reference to the accompanying drawings. Preferred embodiments of the present invention are shown in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the present invention.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the embodiments of the invention is for the purpose of describing particular implementations only and is not intended to limit the invention.

[0039] Please see Figure 1 and Figure 2 The present invention provides an illumination device 10, including a laser source 102, a wavelength conversion element 104, and a diffusion element 110. The laser source 102 is used to emit laser light; the wavelength conversion element 104 is used to convert at least part of the received laser light into fluorescence; the diffusion element 110 is located between the laser source 102 and the wavelength conversion element 104, and the diffusion element 110 includes a first scattering region 113 and a second scattering region 116 surrounding the first scattering region 113. The diffusion angle θ1 of the first scattering region 113 is smaller than the diffusion angle θ2 of the second scattering region 116. The laser light is incident on the wavelength conversion element 104 after being scattered by the first scattering region 113 and the second scattering region 116.

[0040] Specifically, in this embodiment, the laser source 102 may include a laser, which may be a single laser, a laser chip, a laser diode (LD), or other laser emitting devices. It is understood that the laser source 102 may also include two, three, or more lasers, and multiple lasers may be arranged in an array to increase the laser intensity.

[0041] In this embodiment, the laser source 102 can be a blue light source. In other embodiments, the laser source 102 can also be a violet light source, a red light source, or a green light source, as long as it meets the condition of emitting laser light. It can also be a combination of multiple color laser light-emitting units.

[0042] The wavelength conversion element 104 can be circular, rectangular, elliptical, or trapezoidal. In this embodiment, a circular shape is used as an example. As an example, the wavelength conversion element 104 can be a wavelength conversion layer directly coated on the reflective substrate. The wavelength conversion layer can be a wavelength conversion material layer or a film formed by sintering a wavelength conversion material with an adhesive, etc., wherein the wavelength conversion material includes, but is not limited to, phosphors, quantum dot materials, etc. Of course, the wavelength conversion element 104 can also be a transmissive wavelength conversion element 104. As another example, the wavelength conversion element 104 can include a transparent substrate and a wavelength conversion material doped inside the transparent substrate.

[0043] In this embodiment, the wavelength conversion element 104 may include a yellow phosphor, which can generate yellow fluorescence when excited by a blue laser. The wavelength conversion element 104 may be a reflective color wheel. The wavelength conversion material may also be a yellow-green phosphor, etc. In other embodiments, the wavelength conversion element 104 may have red, green, and blue regions, with the wavelength conversion materials for each region corresponding to red, green, and blue phosphors, respectively. It is understood that the wavelength conversion element 104 may not simultaneously include red, green, and blue regions; for example, it may include one or two of them.

[0044] The wavelength conversion element 104 is used to convert laser light into fluorescence. Specifically, after the laser light is incident on the wavelength conversion element 104, it excites the phosphor on the surface of the wavelength conversion element 104 to produce fluorescence, and then emits a mixed light including fluorescence and laser light. The wavelength conversion element 104 can emit fluorescence and laser light in a certain order, or it can emit fluorescence and laser light simultaneously.

[0045] The diffuser element 110 can also be circular, rectangular, elliptical, or trapezoidal. In this embodiment, a circular shape is used as an example. The function of the diffuser element 110 is to diffuse the laser emitted from the laser source 102, thereby expanding the laser spot incident on the wavelength conversion element 104 and reducing the yellow spot at the edge of the emitted spot. The diffusion angle of the diffuser element 110 is not the same everywhere. Specifically, the diffuser element 110 includes a first scattering region 113 and a second scattering region 116 surrounding the first scattering region 113. The first scattering region 113 corresponds to the central region of the diffuser element 110, and the second scattering region 116 corresponds to the edge region of the diffuser element 110. The diffusion angle θ1 of the first scattering region 113 is smaller than the diffusion angle θ2 of the second scattering region 116, meaning that the degree of scattering of the laser by the first scattering region 113 is less than the degree of scattering of the laser by the second scattering region 116, that is, the haze value of the first scattering region 113 is less than the haze value of the second scattering region 116. Haze is the percentage of transmitted light intensity that deviates from the incident light by more than 2.5° from the total transmitted light intensity. A higher haze value indicates a decrease in film gloss and transparency, especially in image quality. The diffusion angle θ1 of the first scattering region 113 is smaller than the diffusion angle θ2 of the second scattering region 116, meaning that the divergence angle of the laser light passing through the first scattering region 113 is smaller than that of the laser light passing through the second scattering region 116.

[0046] Because the central region has little or no diffusion, and the light from the edge region diffuses into the central region, the intensity of the light in the central region, i.e., the central illuminance of the emitted light spot, does not decrease or decreases only slightly. This allows the light source to illuminate a longer distance. The larger diffusion angle in the edge region expands the edge area of ​​the laser spot, allowing the laser spot on the wavelength conversion element 104 to cover the fluorescent spot, specifically the yellow fluorescent spot. This reduces the yellow spot at the edge of the emitted light spot, improving image quality. Because the diffusion angle θ2 of the second scattering region 116 is large, the laser power in the edge region is very low. The laser is reflected and excited on the surface of the wavelength conversion element 104, and because the power is so low, it is not easily visible to the naked eye. Figures 3 to 6 As shown, Figure 3 and Figure 4 These are the laser intensity distributions in the central and edge regions of the wavelength conversion element when there is no diffusion element. Figure 5 and Figure 6The laser intensity distributions in the central and edge regions of the wavelength conversion element 104 are shown respectively when the laser is scattered by the diffusion element 110. By comparison, it can be seen that without the diffusion element 110, there is no laser distribution in the edge region of the wavelength conversion element 100. With the diffusion element 110, the Gaussian distribution law of the laser beam is changed, resulting in laser distribution in the edge region of the wavelength conversion element 100. The laser spot area is larger. Moreover, since the diffusion angle θ1 of the first scattering region 113 is smaller than the diffusion angle θ2 of the second scattering region 116, the laser power density in the central region decreases less, while the laser power density in the edge region increases. This is more consistent with the diffusion distribution of fluorescence, improves imaging quality, and increases the illumination range.

[0047] As an example, the central region can refer to a circular region with the center of the diffusion element 110 as the center and half the radius of the diffusion element 110 as the radius, while the edge region refers to the annular region excluding the central region.

[0048] Please see Figure 7 In this embodiment, the first scattering region 113 can correspond to the central region, and the second scattering region 116 can correspond to the edge region. The center of the first scattering region 113 can coincide with the center of the second scattering region 116. The center of the laser beam at the diffuser element coincides with the center of the first scattering region 113, meaning the laser beam spot can coincide with the first scattering region 113 and the second scattering region 116 to the maximum extent, thereby improving the central illuminance of the emitted beam spot. The diffusion angle θ1 of the first scattering region 113 is a constant, and the diffusion angle θ2 of the second scattering region 116 is also a constant. The diffusion angle θ2 of the second scattering region 116 is greater than the diffusion angle θ1 of the first scattering region 113. For example, the diffusion angle θ1 of the first scattering region 113 is 10°, and the diffusion angle θ2 of the second scattering region 116 is 30°. Another example is that the diffusion angle θ1 of the first scattering region 113 is 20°, and the diffusion angle θ2 of the second scattering region 116 is 50°. That is, the diffusion element 110 is a step diffusion, that is, the diffusion angle changes abruptly from one value of the first scattering region 113 to another value of the second scattering region 116.

[0049] In this embodiment, the laser beam may pass through the entire first scattering region 113 and at least part of the second scattering region 116 before entering the wavelength conversion element 104. Since the first scattering region 113 is located in the middle and has a small diffusion angle, this ensures that the emitted light spot has a strong central illumination; since the second scattering region 116 is located at the edge and has a large diffusion angle, it can reduce the yellow light spot at the edge of the emitted light spot.

[0050] Please see Figure 8In one embodiment, the diffusion angle θ1 of the first scattering region 113 is 0°. That is, the first scattering region 113 has no diffusion function. For example, transparent glass. The second scattering region 116 may include a scattering material, which may be located on the surface of the second scattering region 116 or inside the second scattering region 116.

[0051] In another embodiment, the diffusion element 110 has a through hole, the first scattering region 113 is a through hole, and the diffusion angle θ1 of the first scattering region 113 can also be 0°.

[0052] Please see Figure 9 , Figure 10 and Figure 11 In some other embodiments, the diffusion angle θ1 of the first scattering region 113 gradually increases from the center to the edge of the diffusion element 110, wherein the diffusion angle corresponding to the center can be 0° or greater than 0°, and the diffusion angle θ2 of the second scattering region 116 also gradually increases. The increase can be uniform, also called linear, such as... Figure 9 As shown. Please refer to [the original text]. Figure 10 The increase can be exponential, logarithmic, or irregular. That is, the diffusion element 110 can be a gradual diffusion. Please refer to [link / reference]. Figure 11 In this embodiment, the maximum value of the diffusion angle θ1 of the first scattering region 113 can be less than the minimum value of the diffusion angle θ2 of the second scattering region 116, that is, the diffusion angle of the diffusion element 110 has an abrupt change when transitioning from the first scattering region 113 to the second scattering region 116.

[0053] In one embodiment, the diffusion angle of the first scattering region 113 (or the second scattering region 116) increases in the same way from the center to the edge of the diffusion element 110 along different directions, meaning that the diffusion angle at any point on any concentric circle is the same. In another embodiment, the diffusion angle of the first scattering region 113 (or the second scattering region 116) increases in different ways from the center to the edge of the diffusion element 110 along different directions, meaning that the diffusion angle at each point on any concentric circle is not all the same. As an example, the diffusion angles of the first scattering region 113 and the second scattering region 116 on the X-axis and Y-axis can be different, wherein the X-axis and Y-axis are perpendicular to each other and both are parallel to the surface of the diffusion element. Preferably, the diffusion angles of the first scattering region 113 and the second scattering region 116 on the X-axis and Y-axis are adapted to the divergence angles of the fast axis and slow axis of the laser beam, respectively, so that after the laser beam is scattered by the diffusion element 110, the divergence angles of the laser beam on the X-axis and Y-axis are similar or the same.

[0054] In other embodiments, the diffusion angle of the first scattering region 113 gradually increases from the center to the edge of the diffusion element 110, and the diffusion angle of the second scattering region 116 also gradually increases. The maximum value of the diffusion angle θ1 of the first scattering region 113 can be equal to the minimum value of the diffusion angle θ2 of the second scattering region 116. That is, the diffusion angle of the diffusion element 110 continuously increases from the center to the edge, meaning that there is no abrupt change in the diffusion angle of the diffusion element 110 when transitioning from the first scattering region 113 to the second scattering region 116.

[0055] In some other embodiments, the diffusion angle θ1 of the first scattering region 113 can be a constant value, while the diffusion angle θ2 of the second scattering region 116 gradually increases. The minimum value of the diffusion angle θ2 of the second scattering region 116 can be greater than or equal to the diffusion angle θ1 of the first scattering region 113. In another embodiment, the diffusion angle θ2 of the second scattering region 116 can be a constant value, while the diffusion angle θ1 of the first scattering region 113 gradually increases.

[0056] In summary, the lighting device 10 provided by the present invention, by setting a diffusion element 110, including a first scattering area 113 and a second scattering area 116 surrounding the first scattering area 113, and the diffusion angle θ1 of the first scattering area 113 is smaller than the diffusion angle θ2 of the second scattering area 116, reduces the yellow spot at the edge of the emitted light spot without affecting the center illuminance of the emitted light spot, thereby improving the imaging quality.

[0057] Please see Figure 12 The lighting device 10 also includes a first optical system 100 disposed between the diffusion element 110 and the wavelength conversion element 104, and a second optical system 120 disposed between the laser source 102 and the diffusion element 110. The laser emitted from the laser source 102 is incident on the diffusion element 110 through the second optical system 120, and the laser scattered by the diffusion element 110 is incident on the wavelength conversion element 104 after passing through the first optical system 100.

[0058] In one embodiment, the first optical system 100 includes a prism 130, and the second optical system 120 includes a converging lens 122 disposed on the light-emitting side of the laser source. The converging lens 122 is located between the laser source 102 and the diffusion element 110. The converging lens 122 is used to converge the laser emitted from the laser source 102. The laser emitted from the laser source 102 passes through the converging lens 122, the diffusion element 110 and the prism 130 in sequence before entering the wavelength conversion element 104.

[0059] In this embodiment, the converging lens 122 can be a biconvex lens. In other embodiments, the converging lens 122 can also be a plano-convex lens or a concave-convex lens; the specific shape can be designed according to actual conditions to satisfy the converging effect of light.

[0060] The prism 130 is located between the diffuser element 110 and the wavelength conversion element 104. The prism 130 can guide the light emitted from the diffuser element 110 to the wavelength conversion element 104. By setting the prism 130, the transmission direction of the laser can be changed, thereby folding the laser beam path and reducing the size of the illumination device 10.

[0061] The prism 130 includes an incident surface 132, a total reflection surface 134, and a refractive surface 136. The angle between the incident surface 132 and the total reflection surface 134 is an acute angle, and the angle between the incident surface 132 and the refractive surface 136 is also an acute angle. The laser emitted from the laser source 102 enters the prism 130 from the incident surface 132, and after total reflection by the total reflection surface 134, it exits from the refractive surface 136 to the wavelength conversion element 104.

[0062] Second Embodiment

[0063] Please see Figure 13 This embodiment provides an illumination device 20. Unlike the first embodiment, the first optical system 200 of this embodiment includes a first optical path guiding element 201 and a collecting lens 202, and the second optical system 220 includes a converging lens 221 and a second optical path guiding element 223. The converging lens 221 is disposed on the light-emitting side of the laser light source 102.

[0064] The function of the converging lens 221 is to focus the laser emitted from the laser source 102. The converging lens 221 can also be a biconvex lens, a plano-convex lens, or a concave-convex lens.

[0065] The collecting lens 202 is located between the diffuser element 110 and the wavelength conversion element 104, and is close to the wavelength conversion element 104. The function of the collecting lens 202 is to collect the fluorescence emitted by the wavelength conversion element 104. Its shape can be the same as that of the converging lens 221. The curvature of the collecting lens 202 can be greater than that of the converging lens 221 to enhance the collection effect of fluorescence.

[0066] In this embodiment, please continue to refer to Figure 13The first optical path guiding element 201 can be located between the diffuser element 110 and the collecting lens 202, that is, the first optical path guiding element 201 and the collecting lens 202 are sequentially located between the diffuser element 110 and the wavelength conversion element 104. The first optical path guiding element 201 is used to reflect the laser emitted from the diffuser element and transmit the fluorescence emitted from the wavelength conversion element 104. Specifically, the first optical path guiding element 201 can be a regional film, which includes a central coated area and a transparent area (not labeled) surrounding the coated area. A blue-reflecting and yellow-transmitting coating is formed on the coated area, which can reflect blue laser light and transmit yellow fluorescence. Since the laser beam spot is small, the area of ​​the coated area is also small. The second optical path guiding element 223 can be located between the converging lens 221 and the diffuser element 110. The second optical path guiding element 223 can be a reflective optical element, such as a mirror or a total internal reflection prism. The laser emitted from the laser source 102 is focused by the converging lens 221 and incident on the second optical path guiding element 223. After being reflected by the second optical path guiding element 223, the laser is scattered by the diffuser element 110. The scattered laser is reflected by the first optical path guiding element 201, passes through the collecting lens 202, and then enters the wavelength conversion element 104. The wavelength conversion element 104 converts a portion of the laser into fluorescence. The fluorescence and the remaining laser mix to form white light, which is emitted from the wavelength conversion element 104. The fluorescence and the remaining laser emitted from the wavelength conversion element 104 are collected by the collecting lens 203 and then emitted through the first optical path guiding element 201. Specifically, the fluorescence and the remaining laser can be emitted through the transparent area of ​​the first optical path guiding element 201, and the fluorescence can also be emitted through the coated area of ​​the first optical path guiding element 201.

[0067] The lighting device 20 provided in this embodiment can fold the light path by setting the second light path guiding element 223 and the first light path guiding element 201, which makes reasonable use of the light path, shortens the transmission distance of the laser along the emission direction, and reduces the size of the lighting device.

[0068] Third Embodiment

[0069] Please see Figure 14 This embodiment provides an illumination device 30. Unlike the first embodiment, the first optical system 300 of this embodiment includes a first optical path guiding element 325 and a collecting lens 302, and the second optical system 320 includes a converging lens 321 and a second optical path guiding element 323.

[0070] A converging lens 321 is disposed on the light-emitting side of the laser source 102 to converge the laser emitted from the laser source 102. A second optical path guiding element 323 and a first optical path guiding element 325 are sequentially located between the converging lens 321 and the diffuser element 110. The second optical path guiding element 323 guides the laser emitted from the converging lens 321 to the first optical path guiding element 325. The first optical path guiding element 325 reflects the laser emitted from the second optical path guiding element 323 and transmits the fluorescence emitted from the wavelength conversion element 104. A collecting lens 321 is located between the diffuser element 110 and the wavelength conversion element 104. Similar to Embodiment 2, in this embodiment, the first optical path guiding element 325 can be a regional diaphragm, which includes a central coated area and a transparent area (not labeled) surrounding the coated area. The coated area has a blue-reflecting and yellow-transmitting coating, capable of reflecting blue laser light and transmitting yellow fluorescence. The second optical path guiding element 323 can be a reflective optical element, such as a mirror or a total internal reflection prism.

[0071] The laser emitted from the laser source 102 is focused by the converging lens 321 and incident on the second optical path guiding element 323. The laser is reflected by the first optical path guiding element 325 and the second optical path guiding element 323 in sequence and then incident on the diffuser element 110. The laser scattered by the diffuser element 110 passes through the collecting lens 321 and then incident on the wavelength conversion element 104. The fluorescence emitted from the wavelength conversion element 104 passes through the collecting lens 321 and the diffuser element 110 in sequence and then passes through the first optical path guiding element 325 before being emitted. Specifically, the fluorescence and the remaining laser can be emitted through the transparent area of ​​the first optical path guiding element 325, and the fluorescence can also be emitted through the coated area of ​​the first optical path guiding element 325.

[0072] The lighting device 30 provided in this embodiment can also reduce the size of the lighting device 30.

[0073] Fourth embodiment

[0074] Please see Figure 15 This embodiment provides an illumination device 40. Unlike the first embodiment, the first optical system 400 of this embodiment includes a first optical path guiding element 425 and a collecting lens 402, and the second optical system 420 includes a converging lens 421 and a second optical path guiding element 423.

[0075] A converging lens 421 is disposed on the light-emitting side of the laser source 102 to converge the laser emitted from the laser source 102. A second optical path guiding element 423 is located between the converging lens 421 and the diffuser element 110 to guide the laser emitted from the converging lens 421 to the diffuser element 110. A first optical path guiding element 425 reflects the laser emitted from the second optical path guiding element 423 and transmits the fluorescence emitted from the wavelength conversion element 104. The first optical path guiding element 425 is disposed on the diffuser element 110 away from the second optical path guiding element 423. On one side of the optical path guiding element 423, the collecting lens 421 is located between the diffuser element 110 and the wavelength conversion element 104. Similar to Embodiment 2, in this embodiment, the first optical path guiding element 325 can be a regional film, which includes a central coated area and a transparent area (not labeled) surrounding the coated area. The coated area has a blue-reflecting and yellow-transmitting coating, capable of reflecting blue laser light and transmitting yellow fluorescence. The second optical path guiding element 323 can be a reflective optical element, such as a mirror or a total internal reflection prism. The coated area of ​​the first optical path guiding element 325 forms a reflective surface 4251 for reflecting laser light. The diffuser element 110 is disposed on the reflective surface 4251 on the side opposite to the second optical path guiding element 423. The connection scheme between the diffuser element 110 and the first optical path guiding element 425 is not specifically limited here; they can be bonded with optical adhesive or fixed by other mechanical means.

[0076] The laser emitted from the laser source 102 is focused by the converging lens 421 and incident on the second optical path guiding element 423. The second optical path guiding element 423 reflects the laser onto the diffuser element 110. The diffuser element 110 scatters the received laser. The scattered laser is reflected again by the first optical path guiding element 425 and passes through the diffuser element 110. In this embodiment, the laser can undergo two scatterings by the diffuser element 110. The scattered laser emitted from the diffuser element passes through the collecting lens 402 and is incident on the wavelength conversion element 104. The fluorescence emitted from the wavelength conversion element 104 and the remaining laser are collected by the collecting lens 402 and then pass through the diffuser element 110 and the first optical path guiding element 425 in sequence before being emitted. Specifically, the fluorescence and the remaining laser can be emitted through the transparent area of ​​the first optical path guiding element 425, and the fluorescence can also be emitted through the coated area of ​​the first optical path guiding element 425.

[0077] The lighting device 40 provided in this embodiment places the diffusion element 110 on the first optical path guiding element 425. This eliminates the need to reserve additional installation space for the diffusion element 110, reducing production costs and decreasing the size of the lighting device 40. Furthermore, the laser light is scattered twice by the diffusion element 110, improving the scattering effect.

[0078] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A lighting device, characterized in that, include: A laser source, wherein the laser source is used to emit laser light; A wavelength conversion element, wherein the wavelength conversion element is used to convert a portion of the received laser light into fluorescence, and the fluorescence is mixed with the remaining laser light to form white light; wherein the wavelength conversion element includes a yellow phosphor; and A diffusion element is located between the laser source and the wavelength conversion element. The diffusion element includes a first scattering region and a second scattering region surrounding the first scattering region. The diffusion angle of the first scattering region is smaller than the diffusion angle of the second scattering region. The laser light is incident on the wavelength conversion element after being scattered by the first scattering region and the second scattering region. The diffusion element has a through hole, and the first scattering region is the through hole.

2. The lighting device according to claim 1, characterized in that, The laser light passes through the entire first scattering region and at least a portion of the second scattering region before being incident on the wavelength conversion element.

3. The lighting device according to claim 1, characterized in that, The center of the first scattering region coincides with the center of the second scattering region, and the center of the laser spot on the diffusion element coincides with the center of the first scattering region.

4. The lighting device according to claim 1, characterized in that, The first scattering region and the second scattering region have different diffusion angles on the X-axis and Y-axis, wherein the X-axis and the Y-axis are perpendicular to each other and are both parallel to the surface of the diffusion element.

5. The lighting device according to claim 1, characterized in that, The diffusion angle of the first scattering region is a constant, and the diffusion angle of the second scattering region is also a constant.

6. The lighting device according to claim 5, characterized in that, The diffusion angle of the first scattering region is 0°.

7. The lighting device according to any one of claims 1-6, characterized in that, The lighting device further includes a first optical system disposed between the diffusion element and the wavelength conversion element, wherein the laser light scattered by the diffusion element passes through the first optical system and is incident on the wavelength conversion element.

8. The lighting device according to claim 7, characterized in that, The lighting device further includes a second optical system disposed between the laser source and the diffusion element, wherein the laser emitted from the laser source is incident on the diffusion element via the second optical system.

9. The lighting device according to claim 8, characterized in that, The first optical system includes a prism, which has an incident surface, a total reflection surface, and a refractive surface. The angle between the incident surface and the total reflection surface is an acute angle, and the angle between the incident surface and the refractive surface is also an acute angle. The laser emitted from the laser source enters the prism from the incident surface, is reflected by the total reflection surface, and exits from the refractive surface to the wavelength conversion element. The second optical system includes a converging lens disposed on the light-emitting side of the laser source, which is used to converge the laser emitted from the laser source.

10. The lighting device according to claim 8, characterized in that, The first optical system includes a first optical path guiding element and a collecting lens, and the second optical system includes a converging lens and a second optical path guiding element. The converging lens is disposed on the light-emitting side of the laser source and is used to converge the laser emitted from the laser source. The second optical path guiding element is located between the converging lens and the diffuser element and is used to guide the laser emitted from the converging lens to the diffuser element. The first optical path guiding element and the collecting lens are sequentially located between the diffuser element and the wavelength conversion element. The first optical path guiding element is used to reflect the laser emitted from the diffuser element and transmit the fluorescence emitted from the wavelength conversion element. The laser reflected by the first optical path guiding element is incident on the wavelength conversion element after passing through the collecting lens. The fluorescence emitted by the wavelength conversion element is collected by the collecting lens and then emitted through the first optical path guiding element.

11. The lighting device according to claim 8, characterized in that, The first optical system includes a first optical path guiding element and a collecting lens, and the second optical system includes a converging lens and a second optical path guiding element. The converging lens is disposed on the light-emitting side of the laser source and is used to converge the laser emitted from the laser source. The second optical path guiding element and the first optical path guiding element are sequentially located between the converging lens and the diffuser. The second optical path guiding element is used to guide the laser emitted from the converging lens to the first optical path guiding element. The first optical path guiding element is used to reflect the laser emitted from the second optical path guiding element and transmit the fluorescence emitted from the wavelength conversion element. The collecting lens is located between the diffuser and the wavelength conversion element. The laser reflected by the first optical path guiding element passes sequentially through the diffuser and the collecting lens before entering the wavelength conversion element. The fluorescence emitted from the wavelength conversion element passes sequentially through the collecting lens and the diffuser before passing through the first optical path guiding element and exiting.

12. The lighting device according to claim 8, characterized in that, The first optical system includes a first optical path guiding element and a collecting lens, and the second optical system includes a converging lens and a second optical path guiding element. The converging lens is disposed on the light-emitting side of the laser source and is used to converge the laser emitted from the laser source. The second optical path guiding element is located between the converging lens and the diffuser element and is used to guide the laser emitted from the converging lens to the diffuser element. The first optical path guiding element is disposed on the side of the diffuser element away from the second optical path guiding element and is used to reflect the laser emitted from the second optical path guiding element and transmit the fluorescence emitted from the wavelength conversion element. The collecting lens is located between the diffuser element and the wavelength conversion element. The first optical path guiding element reflects the laser scattered by the diffuser element and, after passing through the collecting lens, enters the wavelength conversion element. The fluorescence emitted from the wavelength conversion element is collected by the collecting lens and then passes through the diffuser element and the first optical path guiding element in sequence before being emitted.

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