WO2020019753A1

WO2020019753A1 - Illumination apparatus

Info

Publication number: WO2020019753A1
Application number: PCT/CN2019/081649
Authority: WO
Inventors: 胡飞; 徐梦梦; 张贤鹏; 李屹
Original assignee: 深圳市绎立锐光科技开发有限公司
Priority date: 2018-07-26
Filing date: 2019-04-08
Publication date: 2020-01-30
Also published as: CN110778926A; CN110778926B

Abstract

Disclosed is an illumination apparatus, comprising: an excited light source for emitting excited light having a first wavelength distribution; and a light conversion apparatus, comprising: a light guide, the light guide comprising a first end, a second end opposite the first end, and a first face and a second face connected to the first end and the second end, wherein the first end is provided with a light incident face of the light conversion apparatus, and the first face constitutes a light emergent face of the light conversion apparatus; a reflective diffuser, arranged at the second end of the light guide and used for diffusing the excited light and reflecting same back to the interior of the light guide; and a wavelength converter, arranged adjacent to the second face of the light guide and used for converting the excited light into excited light having a second wavelength distribution, and reflecting the excited light back to the interior of the light guide so as to enable the excited light to be emitted from the first face of the light guide. By means of the present invention, the uniformity of light emitted by the illumination apparatus is improved, and the problems of heat concentration and conversion efficiency reduction caused by an excited light source with an ultra-high power density directly exciting a wavelength converter are avoided.

Description

Lighting device

Technical field

The invention relates to the field of lighting, in particular to a lighting device.

Background technique

LED light source is the fourth generation light source after incandescent, fluorescent and high-intensity gas lamps. It has the advantages of energy saving, environmental protection, long life, small size, light weight, sturdy structure and low operating voltage. However, current LED light sources also exist Problems such as low brightness and sudden drop in efficiency. As an alternative, a light source (hereinafter referred to as a "laser fluorescent light source") that emits light with a laser-excited fluorescent material is receiving more and more attention due to its advantages such as high electro-optical conversion efficiency, high brightness, inefficient drop, and small size.

At present, the commonly used laser fluorescent light source uses blue laser light as the excitation light source, and the excitation wavelength conversion element obtains a specific wavelength of emitted light. However, because of the small laser spot area and the excessively high excitation light power density in this laser fluorescence light source, wavelength conversion materials will be caused. Problems such as low luminous efficiency and local overheating. To solve these problems, the current common solution is to rotate or vibrate the wavelength material so that the excitation light power density or heat is dispersed. However, this method has reliability and other aspects due to the addition of moving parts. The problem.

In addition, the use of a light guide element to even the excitation light can also avoid the problem of excessive concentration of heat and lower conversion efficiency in the wavelength conversion element due to the high excitation light power. For example, patent documents: CN105074945A, EP2947484, WO2014198619, etc. In the light source, a light guide element is used to achieve uniform light. However, in the above patent documents, a transparent fluorescent light guide element is usually made of a single crystal or transparent ceramic of YAG: Ce. This kind of light guide element converts excitation light into light while uniforming and guiding light. The light of another wavelength distribution, that is, the role of light guide and wavelength conversion at the same time, any position of the light guide element may be the light emitting center, making it difficult to control the uniformity of light output.

In some other prior arts, a light guide is set separately from wavelength conversion, and a point light source is converted to a surface light source using a light guide, and then the phosphor is irradiated to reduce the power density of the excitation light irradiated onto the phosphor. However, in such prior art, the arrangement of the light guide member and the peripheral parts of the light guide member such as the reflection member is not optimal, and the effect on light uniformity is not ideal.

Summary of the Invention

In view of the above circumstances, the present invention provides a lighting device to solve the above problems.

A lighting device includes:

An excitation light source that emits excitation light with a first wavelength distribution; and

A light conversion device includes: a light guide, the light guide includes a first end, a second end opposite to the first end, a first surface connected between the first end and the second end, and a second Surface, the first end is provided with a light incident surface of the light conversion device, and the first surface constitutes a light exit surface of the light conversion device; a reflective diffusion member, the reflective diffusion member is disposed on the light guide The second end of the element is used to diffuse and reflect the excitation light back to the light guide; and a wavelength conversion element, the wavelength conversion element is disposed adjacent to the second surface of the light guide, and is used to convert the excitation light into a first The two-wavelength-received laser light reflects the laser-received light back to the light guide and exits from the first surface of the light guide.

The illumination device provided by the embodiment of the present invention has the advantages that the light guide is separated from the wavelength conversion member and a reflective diffusion member is provided on the opposite end surface of the light incident surface of the light conversion device, so that the The excitation light does not directly enter the wavelength conversion member, but after being transmitted by the light guide, the light distribution is changed at the reflective diffuser, and then the light is incident on the first end and the first end of the light guide with a more uniform light distribution. A wavelength converter with a second surface position between the two ends. On the one hand, the wavelength conversion member becomes a surface light source (different from the bulk light source of the transparent fluorescent light guide in the background art), which is beneficial to regulating the uniformity of light output of the lighting device; on the other hand, the light guide member and the reflective type provided at the end of the light guide member The diffuser converts excitation light with a small spot area and high power density into excitation light with a large spot area and low power density, which effectively avoids heat concentration and conversion caused by an excessively high-density excitation light source directly exciting a wavelength conversion member. At the same time, the efficiency is reduced. At the same time, the reflective diffuser provided at the end of the light guide further improves the uniformity of light. In addition, compared with the "bulk light source" type background technology, the wavelength conversion element of the present invention can receive a large area of uniform excitation light irradiation over the entire surface, and the excitation light power will not be different due to the distance from the excitation light source. , So that the wavelength converter can emit light and heat more uniformly.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic structural diagram of a first embodiment of a lighting device according to the present invention.

FIG. 2 is a schematic structural view of the light conversion device of the lighting device shown in FIG. 1 at another angle.

FIG. 3 is a schematic structural diagram of a second embodiment of a lighting device according to the present invention.

FIG. 4 is a schematic structural diagram of a third embodiment of a lighting device according to the present invention.

FIG. 5A and FIG. 5B are comparison diagrams of light guiding principles of light guides in the first and third embodiments of the lighting device of the present invention, where FIG. 5A is a principle diagram of light guides of the light guide in the first embodiment, and FIG. 5B is The schematic diagram of the light guide of the light guide in the second embodiment.

FIG. 6 is a schematic structural diagram of a fourth embodiment of a lighting device according to the present invention.

FIG. 7 is a schematic structural diagram of a fifth embodiment of a lighting device according to the present invention.

detailed description

In the following, the technical solutions in the embodiments of the present invention will be clearly and completely described with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, but not all of them. Based on the embodiments of the present invention, all other embodiments obtained by a person of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

Unless defined otherwise, 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 belongs. The term "or / and" as used herein includes any and all combinations of one or more of the associated listed items.

Please refer to FIG. 1 and FIG. 2. FIG. 1 and FIG. 2 are schematic structural diagrams of a lighting device according to a first embodiment of the present invention. The lighting device 1 includes an excitation light source 11, a light guide device 12, and a light conversion device 13. The excitation light source 11 emits excitation light with a first wavelength distribution and a small spot area. In this embodiment, the excitation light source 11 is a point light source that emits excitation light with a first wavelength distribution. The light guide device 12 is used for The excitation light emitted by the excitation light source 11 is incident on a specific position of the light conversion device 13 at an appropriate angle; the light conversion device 13 is used to make the spot area of the first wavelength distribution emitted by the excitation light source 11 small (such as a point light source) The excitation light that is converted into the second wavelength distribution of a larger spot area (surface light source) emits light that includes at least a light guide 14, a wavelength conversion member 15, and a reflective diffusion member 16, wherein the light guide 14 and the wavelength conversion member 15 is disposed separately, and the reflective diffuser 16 is disposed at the end of the light guide member 14. The reflective diffuser 16 cooperates with the light guide member 14 to expand the area of the excitation light spot and further improve the uniformity of light. For example, a point light source is converted into a surface light source. Then, the wavelength conversion element 15 is excited to obtain the emitted light with the second wavelength distribution. In this embodiment, the separate arrangement means that the light guide 14 and the wavelength conversion member 15 are two elements that are separable from each other and do not form part of each other.

In this embodiment, the lighting device 1 is a laser lighting device, and the excitation light source 11 may be a single or multiple laser light sources, preferably a blue laser light source. The light guiding device 12 is a collimating lens 12 a disposed between the excitation light source 11 and the light conversion device 13. Of course, in other embodiments, the light guiding device 12 may be a collimating lens 12 a and other optical devices. The combination of the elements only needs to make the excitation light emitted from the excitation light source 11 incident on a specific position of the light conversion device 13 at an appropriate angle. In other embodiments, the light guiding device 12 may also be an optical device such as an optical fiber or a light rod.

The wavelength conversion member 15 may be a luminescent ceramic or a structure made by dispersing phosphors in silica gel or glass; the light guide member 14 is stacked on the wavelength conversion member 15, and the light guide member 14 is preferably sapphire. Due to the high thermal conductivity of sapphire, the light guide 14 can also improve the heat dissipation of the wavelength conversion member 15 at the same time. The light guide 14 includes a first end 141 close to the light guide device 12 and a second end 142 opposite to the first end 141. The light guide 14 further includes a first end 141 and the second end 142 that are far from the wavelength conversion member 15 One surface 143, a second surface 144 connecting the first end 141 and the second end 142 and close to the wavelength converter 15, and a peripheral side surface connecting the first end 141, the second end 142, the first surface 143, and the second surface 144 (Unlabeled), the first surface 143 and the second surface 144 are both polished to make their surface roughness less than 400 nm, and more preferably less than 100 nm, where the first surface 143 forms the light-emitting surface of the light conversion device 13. The first end 141 of the light guide 14 is provided with a light incident surface of the light conversion device 13. In this embodiment, an end surface of the first end 141 of the light guide member 14 is a light incident surface of the light conversion device 13, and the light guide device 12 reduces the excitation light emitted by the excitation light source 11 to a value smaller than the reciprocal aspect ratio of the light guide member 14. Half of the light divergence half angle is incident on the light incident surface of the light conversion device 13. The aspect ratio of the light guide 14 is obtained by calculating the ratio of the length of the light guide 14 in the direction of incident light to the diameter of the end surface of the second end 142 of the light guide 14. In this embodiment, specifically, the first end of the light guide 14 The distance from 141 to the second end 142 is the length of the light guide 14. The diameter of the largest inscribed circle on the end surface of the second end 142 of the light guide 14 can be regarded as the diameter of the end surface of the second end 142. The light emission angle refers to the angle corresponding to the light cone whose luminous intensity is not less than 50% of the luminous intensity at the center of the beam.

In addition to the light guide 14 and the wavelength conversion member 15, the light conversion device 13 further includes a light splitter 17, a reflection member 18, and a heat sink 19. Wherein, the light guide member 14 is stacked on the wavelength conversion member 15, and the reflection member 18 includes a plurality of reflection elements. In this embodiment, the reflection member 18 includes a light guide member 14 and a wavelength conversion member. The reflection element 18 a on the side of the 15th peripheral side, and the reflection element 18 b provided on the side of the wavelength converter 15 away from the light guide 14. Since the light guide 14 and the wavelength conversion member 15 are both arranged in a substantially rectangular parallelepiped, and the peripheral side includes two sides, in this embodiment, the reflection element 18a further includes

reflection elements

181a and 183a, and the

reflection elements

181a and 183a are disposed on the light guide. 14 and the peripheral sides of the wavelength conversion element 15 to prevent the excitation light and the laser light from being emitted from the peripheral sides of the light guide 14 and the wavelength conversion element 15. The beam splitter 17 is disposed on the first end 141 of the light guide member 14 and extends to cover the end face of the wavelength conversion member 15 on that side. The beam splitter 17 faces the light guiding device 12. Specifically, in this embodiment, the beam splitter 17 It is disposed adjacent to the light incident surface of the light conversion device 13. In the present embodiment, “adjacent” includes “resistance”, for example, the case where the light splitting member 17 is adjacent to the light conversion device 13 and includes the light splitting member 17 on the light-receiving surface. The reflective diffusion member 16 is disposed on the second end 142 of the light guide member 14 and extends to cover the end face of the wavelength conversion member 15 on the side, and is used to diffuse and reflect the excitation light emitted from the second end 142 of the light guide member 14 and reflect it back to the light guide member 14. . The

reflective elements

181a, 183a and the reflective diffuser 16 preferably have a reflectance greater than 90% in the range of 400-800 nm, and may be specular reflective elements or diffuse reflective elements, and the reflective diffuser 16 is preferably a diffuse reflective element. The reflective element 18b preferably has a reflectance greater than 90% in the range of 400-800nm, and may be a specular reflective element or a diffuse reflective element, and is preferably a high-reflection aluminum having a high thermal conductivity. The spectroscopic element 17 is a dichroic sheet 17a that can transmit light of a first wavelength distribution in a specific angular range, and simultaneously reflect light of a first wavelength distribution in other angular ranges and light of a second wavelength distribution. In this embodiment, the dichroic sheet 17a transmits blue light incident at 0-5 degrees, reflects blue light incident at other angles, and reflects light of other wavelengths. The heat sink 19 is a heat sink. Preferably, the heat conductivity of the heat sink is higher than 30 W / m · K. The heat sink 19 is disposed on the other side of the reflective element 18 b facing away from the wavelength conversion member 15 to facilitate The wavelength conversion member 15 dissipates heat.

In this embodiment, between the wavelength conversion element 15 and the light guide 14, between the reflection element 18, the reflective diffusion element 16 and the wavelength conversion element 15 and the light guide 14, and between the dichroic sheet 17 a and the wavelength conversion element 15 and The light guide members 14 are all bonded with a material having a low refractive index and a high light transmittance such as silica gel, so that the corresponding interfaces are in optical contact.

In this embodiment, the blue laser light emitted by the excitation light source 11 is collimated by the collimating lens 12a and then enters the dichroic sheet 17a at an approximately vertical angle, then enters the light guide 14 and enters the reflection diffusion approximately perpendicularly. Piece 16, after diffuse reflection by the reflective diffuser 16, the blue laser light propagates backward at a certain angle, as shown by the arrow in FIG. 1, the blue laser light which propagates backward after diffuse reflection can be divided into three parts I, II and III, where part I of the blue laser light is incident on the first surface 143 of the light guide 14 which is the interface between the light guide 14 and the air, and part of the blue laser is incident on the second surface 144 of the light guide 14 which is the light guide 14 and the wavelength At the interface of the conversion member 15, another part III blue laser light with a smaller proportion propagates back to the light incident surface of the light guide member 14 in a direction parallel to the first surface 143 and the second surface 144 of the light guide member 14.

After part I of the blue laser light enters the first surface 143 of the light guide 14, a small part does not meet the total reflection condition and exits from the first surface 143; the other majority of the blue laser light meets the total reflection condition and is reflected to the light guide The second surface 144 of 14 is the interface between the light guide 14 and the wavelength converter 15. Since the critical angle of total reflection at the second surface 144 is greater than the critical angle of total reflection at the first surface 143, the incident angle is smaller than that of the light guide 14 A part of the blue laser light at the critical angle of the second surface 144 can enter the wavelength conversion element 15 and be converted into light of a second wavelength distribution. The light of the second wavelength distribution is approximately Lambertian light. Finally, the

reflection elements

181a, 183a, reflective diffuser 16, and dichroic sheet 17a, reflective element 18b are emitted from first surface 143 of light guide 14; part of the incident angle that is larger than the critical angle of second surface 144 of light guide 14 is blue The laser cannot enter the wavelength conversion member 15 and is eventually lost in the light guide member 14.

After the part II blue laser light is incident on the second surface 144 of the light guide member 14, the blue laser light that does not satisfy the total reflection condition enters the wavelength conversion member 15 and is converted into light with a second wavelength distribution. The light of the second wavelength distribution is The light with an approximate Lambertian distribution is finally emitted by the first surface 143 of the light guide 14 under the action of the

reflective elements

181a, 183a, the reflective diffuser 16, and the dichroic sheet 17a, and the reflective element 18b; and the other part satisfies total reflection The conditional blue laser light cannot be incident on the wavelength conversion member 15, and can only propagate through the light guide member 14, and is eventually lost.

Part III of the blue laser light is propagated to the light incident surface of the light guide member 14. The part of the blue laser light cannot be incident on the wavelength conversion member 15 and will eventually be lost.

It can be understood that, in order to reduce the loss of the blue laser light, a scattering structure may be provided at the interface between the light guide 14 and the wavelength conversion member 15, such as adding scattering particles such as TiO ₂ between the light guide 14 and the wavelength conversion member 15, or The microstructure is processed on the second surface 144 of the light guide member 14. The size of the scattering particles or the microstructure may be greater than or equal to the wavelength of the blue laser. More preferably, the size of the microstructure is 1 to the wavelength of the blue laser. 10 times, so that the second surface 144 of the light guide 14 has a certain roughness.

It can be understood that, in other embodiments, the surface of the heat dissipating member 19 near the wavelength conversion member 15 can be processed so that the reflectance is greater than 90% in the range of 400-800 nm. At this time, the reflecting element 18b can also be omitted.

It can be understood that, in other embodiments, the side of the wavelength conversion member 15 facing away from the light guide member 14 may be set as a reflective surface, so that the arrangement of the reflective element 18b is omitted.

It can be understood that although the second surface 144 is disposed opposite to the first surface 143 in the above embodiment, in other embodiments, the second surface 144 may be disposed adjacent to the first surface 143, and even when the light guide 14 When the embodiment is a columnar body having more peripheral surfaces than four surfaces, the second surface 144 may be disposed neither facing nor adjacent to the first surface 143.

In the above embodiment, the light guide 14 is a solid light guide. It can be understood that, in other embodiments, the light guide member may be a hollow body. When the light guide member is a hollow body, the wavelength conversion member may be disposed on the inner side of the second surface of the light guide member, and the reflective diffusion member may be disposed on the first side of the light guide member. Inside of both ends. In the embodiment of the present invention, the solid light guide is selected to have a more excellent effect. The reason is that part of the light emitted from the reflective diffuser can be returned to the light guide by the total reflection effect of the interface between the solid light guide and the air. Internal, rather than directly exiting from the light guide, to avoid insufficient utilization of excitation light.

Please refer to FIG. 3, which is a schematic structural diagram of a lighting device according to a second embodiment of the present invention. The lighting device 2 includes an excitation light source 21, a light guide device 22, and a light conversion device 23. The excitation light source 21 emits excitation light with a first wavelength distribution and a small spot area. In this embodiment, the excitation light source 21 is a point light source that emits excitation light with a first wavelength distribution, and the light guide device 22 is used for The excitation light emitted by the excitation light source 11 is incident on a specific position of the light conversion device 23 at an appropriate angle. The light conversion device 23 is used to make the spot area of the first wavelength distribution emitted by the excitation light source 21 smaller (such as a point light source). The excitation light converted into the second wavelength distribution light spot with a larger spot area (surface light source) is emitted, and at least includes a light guide 24, a wavelength conversion member 25, and a reflective diffusion member 26 that are separately disposed, and the light guide 24 is stacked. On the wavelength conversion member 25, a reflective diffusion member 26 is disposed at the end of the light guide member 24. The reflection diffusion member 26 and the light guide member 24 cooperate to expand the spot area of the excitation light and further improve the uniformity of light, for example, to convert a point light source A surface light source is formed, and then the wavelength conversion element 25 is excited to obtain the emitted light with a second wavelength distribution. In this embodiment, the light conversion device 23 further includes a light-splitting member 27, a reflecting member 28, and a heat-dissipating member 29. The reflecting member 28 includes a reflecting element 28a provided on the peripheral side of the light guide member 24 and the wavelength conversion member 25 and a set A reflecting element 28 b on the side of the wavelength conversion member 25 away from the light guide 24. Since the settings of the light guide 24, the wavelength conversion member 25, the reflection member 28, the reflection diffusion member 26, and the heat dissipation member 29 are the same as or similar to those in the first embodiment, the description will not be repeated here.

In this embodiment, the difference from the first embodiment mainly lies in the light guide device and the beam splitter. In this embodiment, the light guiding device 22 is a focusing lens 22a disposed between the excitation light source 21 and the light conversion device 23. Of course, in other embodiments, the light guiding device 22 may also be a focusing lens 22a and other The combination of the optical elements only needs to make the excitation light emitted from the excitation light source 21 incident on a specific position of the light conversion device 23 at an appropriate angle. The beam splitter 27 is disposed on the peripheral sides of the light guide 24 and the wavelength conversion member 25 and is close to the light guide 22. In this embodiment, the beam splitter 27 is an optical expansion beam splitter. According to the difference between the expansion amount of the excitation light and the laser beam, The light-splitting member 27 transmits the excitation light of a specific angular range to the light guide 24 and reflects the laser-excited light and the excitation light of other angular ranges. As a specific implementation manner, the light splitting member 27 is a reflecting element 271, and a through hole 272 is provided in the reflecting element 271. The reflective element 271 may be a specular reflective element or a diffuse reflective element. Preferably, the reflectivity of the reflective element 271 in the range of 400-800 nm is greater than 90%.

In this embodiment, the blue laser light emitted by the excitation light source 21 is focused by the focusing lens 22a, and is incident on the light guide 24 at a specific angle through the through hole 272 of the reflection element 271. The specific angle refers to an angle between the main optical axis of the incident light and the optical axis of the light guide surface of the light guide 24, and the specific angle is not 0. Therefore, compared with the first embodiment, the incident light is not 0. The incident angle of the light incident on the light guide 24 can improve the uniformity of the light emitted from the light guide 24. At the same time, the reflection element 271 provided at the light entrance surface of the light guide 24 can increase the proportion of blue light incident on the wavelength conversion member 25, thereby improving the overall Light-emitting efficiency of the lighting device 2. In addition, by setting the relative positions of the excitation light source 21, the focusing lens 22a, and the reflective element 271, and the positions and apertures of the through holes 272 on the reflective element 271, after the excitation light is focused by the focusing lens 22a, The light spot at the position of the hole 272 is the smallest, thereby ensuring that the blue laser light emitted by the excitation light source 21 can efficiently pass through the through-hole 272 while minimizing the aperture of the through-hole 272, thereby reducing the proportion of light emitted from the light guide 24 through the through-hole 272, further improving Light-emitting efficiency of the entire lighting device 2.

Please refer to FIG. 4, which is a schematic structural diagram of a lighting device according to a third embodiment of the present invention. The illumination device 3 includes an excitation light source 31, a light guide device 32, and a light conversion device 33. The excitation light source 31 emits excitation light with a first wavelength distribution and a small spot area. In this embodiment, the excitation light source 31 In order to emit a point light source with a first wavelength distribution of excitation light, the light guide device 32 is used to inject the excitation light emitted by the excitation light source 31 to a specific position of the light conversion device 33 at an appropriate angle. The light conversion device 33 is used for The excitation light with a smaller spot area (such as a point light source) in the first wavelength distribution is converted into outgoing light having a larger spot area (area light source) in the second wavelength distribution. The light conversion device 33 includes at least a light guide 34, The wavelength conversion member 35 and the reflective diffusion member 36, wherein the light guide member 34 and the wavelength conversion member 35 are disposed separately and the light guide member 34 is stacked on the wavelength conversion member 35, and the reflection diffusion member 36 is provided at the end of the light guide member 34. The reflection type The diffusion member 36 and the light guide member 34 cooperate to expand the spot area of the excitation light and improve the uniformity of the light. For example, a point light source is converted into a surface light source, and then the wavelength conversion member 35 is excited to obtain a second wavelength distribution. Emitted light. In this embodiment, the light conversion device 33 further includes a light-splitting member 37, a reflecting member 38, and a heat-dissipating member 39. The setting of the reflecting member 38, the light-splitting member 37, and the heat-dissipating member 39 may be the same as that of the first embodiment or the second embodiment. The embodiment is the same or similar. For example, as in the first embodiment, the beam splitter 37 may be a dichroic film, or as in the second embodiment, the beam splitter 37 may be a reflective element provided with a through hole. .

The difference between this embodiment and the first and second embodiments mainly lies in the light guide. In the first and second embodiments, the light guides 14 and 24 are substantially rectangular parallelepiped. Therefore, taking the light guide 14 as an example, the light guide The longitudinal section of the element 14 perpendicular to the first surface 143 and the second surface 144 is substantially rectangular, the first surface 143 and the second surface 144 are substantially parallel, and the first surface 143 and the second surface 144 are substantially perpendicular to the peripheral side surface of the light guide 14 In this way, it is easy to cause the light intensity in the region near the reflective diffuser 16 and the reflective element 18a on the first surface 143 to be relatively strong and the light intensity in the region far from the reflective diffuser 16 and the reflective element 18a to be weak. However, in the third embodiment, the first surface 343 of the light guide 34 far from the wavelength conversion member 35 is not parallel to the second surface 344 of the wavelength conversion member 35, the first surface 343 is inclined, and the second surface 344 and the light guide The peripheral side of 34 is in a vertical state, and at least one of the first side 343 and the peripheral side of the light guide 34 is in an inclined state. In this embodiment, the inclined state refers to a non-vertical and non-parallel state. Specifically, The longitudinal section of the light guide 34 perpendicular to the first surface 343 and the second surface 344 is substantially trapezoidal. The first surface 343 and the end surface of the first end 341 of the light guide 34 and the end surface of the second end 342 are inclined. The distance between the first surface 343 and the second surface 344 gradually increases from the first end 341 to the second end 342 of the light guide 34, that is, the distance between the first surface 343 and the second surface 344 is closer to the light guide 34 than the first The end 341 is shorter and longer near the second end 342 (ie, the reflective diffuser 36). In this way, the uniformity of the light emitted by the lighting device 3 can be improved, and the light emitted by the lighting device 3 can be more uniform.

Please refer to FIG. 5A and FIG. 5B. The light guiding principles of the light guides of different shapes in the first and third embodiments are described as follows: The

reflective diffusion members

16, 36 completely change the light distribution of the excitation light to Lambertian. Distributed light, so the

reflective diffusers

16, 36 can be regarded as a Lambertian surface light source. Considering only the total reflection of the

first surfaces

143, 343, the

first surfaces

143, 343 can be roughly regarded as one Mirror. In FIG. 5A corresponding to the first embodiment, due to the total reflection effect of the first surface 143 of the light guide member 14, the Lambertian surface light source is actually a superposition of the reflective diffuser 16 and its virtual image 16 '; In FIG. 5B of the embodiment, the Lambertian surface light source is actually a superposition of the reflective diffuser 36 and its virtual image 36 ', and is emitted from the reflective diffuser 16 and its virtual image 16' or the reflective diffuser 36 and its virtual image 36 '. The 180 ° Lambertian light is incident on the

wavelength converters

15 or 35 disposed adjacent to the

second surfaces

144 and 344. It can be roughly seen that the virtual image 36 'in FIG. 5B is closer to the portion of the wavelength converter 35 near the first end 341 than the virtual image 16' in FIG. 5A, and the center optical axis of the virtual image 36 'is away from the wavelength converter. The portion closer to the first end 341 is closer, so that more light is irradiated to the position of the wavelength conversion member 35 away from the reflective diffusion member 36, thereby improving uniformity. The results obtained from the simulation experiment of illuminance uniformity can also verify this.

It can be understood that, in other embodiments, the shape of the light guide is not limited to a trapezoid, but may be other shapes. Even the first surface of the light guide may be a curved surface, such as a hyperbola, a paraboloid, an ellipsoid, or a curved surface and a plane. Combination, such as a flat plane in the middle and curved surfaces on both sides, as long as the first surface and the second surface of the light guide member are satisfied: the closer to the reflective diffusion member, the greater the distance.

In the above embodiments, the cross-sections of the light guide and the wavelength conversion member perpendicular to the longitudinal section are rectangular. However, it can be understood that in other embodiments, the cross sections of the light guide and the wavelength conversion member may be circular or oval. , Trapezoid, or other shapes other than rectangular. Therefore, the shape of the first surface of the light guide member will be changed accordingly, resulting in a corresponding change in the shape of the light spot emitted by the lighting device.

Please refer to FIG. 6, which is a schematic structural diagram of a lighting device according to a fourth embodiment of the present invention. The lighting device 4 includes an excitation light source 41, a light guide device 42, and a light conversion device 43. The excitation light source 41 emits a first wavelength. The excitation light is distributed and has a small spot area. In this embodiment, the excitation light source 41 is a point light source that emits excitation light of a first wavelength distribution, and the light guide device 42 is configured to convert the excitation light emitted by the excitation light source 41 to An appropriate angle is incident on a specific position of the light conversion device 43 for converting the excitation light with a small spot area of the first wavelength distribution (such as a point light source) into a larger spot area of the second wavelength distribution The (surface light source) emits light. The light conversion device 43 includes at least a light guide 44, a wavelength conversion member 45, and a reflective diffusion member 46. The light guide 44 is separated from the wavelength conversion member 45 and the light guide 44 is stacked. On the wavelength conversion member 45, a reflective diffuser 46 is disposed at the end of the light guide 44. The reflective diffuser 46 and the light guide 44 expand the area of the excitation light spot and improve the uniformity of light. For example, a point light source Into a surface light source, after excitation wavelength conversion member 45 to obtain an emission wavelength of the second light distribution. In this embodiment, the light conversion device 43 further includes a light-splitting member 47, a reflecting member 48, and a heat-dissipating member 49. The reflection member 48, the light-splitting member 47, and the heat-dissipating member 49 may be disposed in the same manner as the first, second, and The three embodiments are the same or similar. For example, as in the first embodiment, the beam splitter 47 may be a dichroic film, or as in the second embodiment, the beam splitter 47 may be a reflection provided with a through hole. For another example, the light guide 44 may have a rectangular parallelepiped shape as in the first and second embodiments, and the light guide 44 may have other shapes as taught in the third embodiment.

This embodiment differs from the first, second, and third embodiments mainly in that a scattering structure 50 is provided on the first surface 443 of the light guide 44, that is, the light exit surface, and the scattering member 50 is used between the light guide 44 and the light guide 44. Low-refractive, high-transmittance materials are bonded so that the interface between them is in optical contact. The scattering structure 50 may be a film containing scattering particles or a film with prisms or other uneven microstructures. The scattering The particles or microstructures may be of the same type or contain two or more different types, and the spatial distribution of the scattering particles or microstructures may be uniform or non-uniform. In this way, the light emitting efficiency and uniformity of the lighting device 4 are further improved.

It can be understood that, in other embodiments, the scattering structure 50 may be omitted, and the microstructure is processed on the first surface 443 of the light guide 44 by machining or etching to form a scattering structure, thereby improving the lighting device 4. Light efficiency and uniformity.

It can be understood that, in other embodiments, a scattering structure may also be provided on the second surface 444 of the light guide 44, such as providing a scattering member or processing a microstructure, which can also improve the light output efficiency and uniformity of the lighting device. When a scattering member is provided on the second surface 444 of the light guide 44, the scattering member may be disposed between the second surface 444 of the light guide 44 and the wavelength conversion member 45.

Please refer to FIG. 7, which is a schematic structural diagram of a lighting device according to a fifth embodiment of the present invention. Unlike the above embodiment, the lighting device 5 in this embodiment further includes two light guides 54 on the first surface 543 of the light guide 54. The dichroic sheet 59 can transmit light of one wavelength distribution (for example, yellow light) and reflect light of another wavelength distribution (for example, blue light), so as to improve the purity of light emitted by the lighting device.

It can be understood that the dichroic sheet 59 may also be replaced by a polarizing beam splitter.

As mentioned above, various embodiments of the lighting device of the present invention are introduced. It can be seen that, compared with the prior art, the light guide is separated from the wavelength conversion member, and a reflective diffusion is provided on the opposite end face of the light incident surface of the light conversion device. So that the excitation light that enters the light guide of the light conversion device does not directly enter the wavelength conversion member, but after being transmitted by the light guide, the light distribution is changed at the reflective diffuser, and then incident with a more uniform light distribution A wavelength converter to a second surface position provided between the first end and the second end of the light guide. On the one hand, the wavelength conversion element becomes a surface light source (different from the bulk light source of the transparent fluorescent light guide in the background art), which is beneficial to regulating the uniformity of light output from the lighting device. In addition, the light guide element and the reflective diffuser provided at the end of the light guide element The excitation light with a small spot area and high power density is converted into the excitation light with a large spot area and a low power density, which effectively avoids the heat concentration caused by the high excitation light power density when the laser is used as the excitation light source to directly excite the wavelength conversion member. And the problem of reduced conversion efficiency, while also improving the uniformity of light. In addition, compared with the "bulk light source" type background technology, the wavelength conversion element of the present invention can receive a large area of uniform excitation light irradiation over the entire surface, and the excitation light power will not be different due to the distance from the excitation light source. , So that the wavelength converter can emit light and heat more uniformly.

Furthermore, by providing a reflective element on the peripheral side of the light guide and the wavelength conversion member, and by providing a reflective element on the side of the wavelength conversion member far from the light guide, the extraction efficiency of the light emitted from the first side of the light guide is ensured, that is, the Light output efficiency. A heat dissipating member is provided on the side of the wavelength converting member far from the light guiding member, and the light guiding member adopts sapphire, which further improves the heat dissipation of the wavelength converting member.

In addition, although the illumination device is exemplified by a laser illumination device in the above embodiment, the illumination device of the present invention is not limited to only a laser illumination device. For other illumination devices, if it includes: 1. a light guide and a wavelength conversion member Separately set, 2. The light guide and the reflective diffuser provided at the end of the light guide diffuse the excitation light with a smaller spot area into excitation light with a larger spot area. 3. The excitation wavelength conversion member with a larger spot area excites the light. The emitted light falls within the spirit of the present invention.

The above embodiments are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail with reference to the above preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or equivalently replaced. All should not depart from the spirit and scope of the technical solution of the present invention.

Claims

A lighting device, comprising:

An excitation light source that emits excitation light with a first wavelength distribution; and

Light conversion device including:

A light guide comprising a first end, a second end opposite to the first end, a first surface and a second surface connected between the first end and the second end, and the first A light incident surface of the light conversion device is disposed on the end, the excitation light is incident into the light guide through the light incident surface, and the first surface constitutes a light exit surface of the light conversion device;

A reflective diffuser, which is disposed at the second end of the light guide and is configured to diffuse and reflect the excitation light back to the inside of the light guide; and

A wavelength conversion element, the wavelength conversion element is disposed adjacent to the second surface of the light guide, and is configured to convert the excitation light into a laser receiving light having a second wavelength distribution and reflect the laser receiving light back to the light guiding member It is emitted from the inside and from the first side of the light guide.
The lighting device according to claim 1, further comprising a light guide device, the light guide device being disposed between the excitation light source and the light conversion device, and configured to convert the excitation light emitted by the excitation light source to A light divergence half angle smaller than 1/2 of the reciprocal of the length-to-diameter ratio of the light guide is incident on the light guide at the first end.
The lighting device according to claim 1, wherein a first surface and a second surface of the light guide member are disposed opposite to each other.
The lighting device according to claim 3, wherein the first surface of the light guide is parallel to the second surface; or the distance between the first surface and the second surface of the light guide is determined by the light guide The first end to the second end gradually increase.
The lighting device according to claim 3, wherein the light conversion device further comprises a light splitting member, the light splitting member is disposed adjacent to the light incident surface of the light conversion device, and the light splitting member transmits a specific angle range The excitation light is directed to the light guide member, and the excitation light of the laser beam and other angle ranges is reflected.
The lighting device according to claim 3, wherein the light conversion device further comprises a light splitting member, the light splitting member is disposed adjacent to the light incident surface of the light conversion device, and the light splitting member is provided with a through hole Reflective elements.
The lighting device according to claim 3, wherein the light guide further comprises a peripheral side surface connecting the first end and the second end, and the light conversion device further comprises a reflector disposed adjacent to the peripheral side surface. The reflector prevents the excitation light and the laser light from being emitted from the peripheral side.
The lighting device according to claim 1, wherein the light conversion device further comprises a heat dissipating member, and the heat dissipating member is disposed on a side of the wavelength conversion member remote from the light guide member.
The lighting device according to claim 1, wherein the light conversion device further comprises a scattering structure, and the scattering structure is disposed or formed on the first surface or the second surface of the light guide, or is disposed or It is formed on the first surface and the second surface of the light guide.
The lighting device according to claim 1, wherein the light guide is made of sapphire.