CN112709973A

CN112709973A - Method for generating composite light by exciting fluorescence with laser and light path structure thereof

Info

Publication number: CN112709973A
Application number: CN202011638896.8A
Authority: CN
Inventors: 杨人毅; 丁洋; 漆凯华; 范振灿; 刘月平; 熊鹤鸣
Original assignee: Dongguan Bituo Intelligent Lighting Co ltd; Shenzhen Betop Electronics Co ltd
Current assignee: Dongguan Bituo Intelligent Lighting Co ltd; Shenzhen Betop Electronics Co ltd
Priority date: 2020-12-31
Filing date: 2020-12-31
Publication date: 2021-04-27
Anticipated expiration: 2040-12-31
Also published as: CN112709973B

Abstract

The application relates to the field of lighting industry, in particular to a light path structure for generating composite light by using laser, which comprises the steps of obtaining incident laser; the incident laser is subjected to reflection processing to obtain emergent laser, and the advancing direction of the emergent laser is vertical to the reflecting surface of the fluorescent body; the emergent laser is processed on a phosphor through fluorescence excitation to generate primary composite light, and the phosphor is provided with a reflecting layer capable of reflecting the primary composite light; and carrying out convergence treatment on the primary composite light to form secondary composite light. The method and the device have the effect of reducing the laser stray light in the composite light.

Description

Method for generating composite light by exciting fluorescence with laser and light path structure thereof

Technical Field

The application relates to the field of lighting industry, in particular to a light path structure for generating composite light by utilizing laser.

Background

Currently, laser lighting can be divided into visible laser lighting and infrared laser lighting, wherein the visible laser lighting has high brightness and high efficiency, and therefore, the laser lighting can be applied to scenes such as automobile lighting, home lighting, commercial lighting of retail industry and the like, or industrial lighting.

In the related art, laser illumination generally refers to exciting a phosphor with laser light to obtain composite light. Referring to fig. 1, the optical path structure in the optical path scheme of the composite optical path structure generated by laser consists of a laser 1, a condenser lens 2, a light diffusion sheet 3, a heat conducting substrate 4, a fluorescent medium 5, a main lens 6 and a large lens 7. The fluorescent medium 5 is capable of converting the laser light into composite light. When laser beams in the light path structure irradiate on a fluorescent medium 5 containing fluorescent crystals and bonding materials, a part of coherent wave laser is converted into incoherent wave light through fluorescent powder, and the other part of coherent wave laser is reflected through gaps among the fluorescent crystals and surface diffuse reflection to become incoherent wave monochromatic light and is transmitted out through gaps among fluorescent crystal particles in the fluorescent medium. The light of incoherent wavelength and the monochromatic light of incoherent wave are mixed to form the composite light of incoherent wave.

In view of the above-mentioned related art, the inventors consider that such a technique has the following drawbacks: since the fluorescent crystal in the fluorescent medium 5 has a small gap therebetween, the laser can easily directly exit from the gap when the gap is large enough for the laser to pass through. When the composite light finally reaches the surface of the object to be irradiated, the leaked laser light is also irradiated to the surface of the object to be irradiated. Since the laser light of a relatively high intensity is applied to the biological tissue to damage the biological tissue to various degrees, the laser light leaked from the fluorescent medium 5 may cause damage to the human body or the living body.

Disclosure of Invention

In order to improve the above-mentioned defects, the present application provides an optical path structure for generating composite light using laser.

The application provides an optical path structure for generating composite light by utilizing laser adopts the following technical scheme:

a method of exciting a phosphor with a laser to produce composite light, comprising:

acquiring incident laser;

the incident laser is subjected to reflection processing to obtain emergent laser, wherein the reflection processing comprises establishing an incident reflection surface and an emergent reflection surface which are integrally arranged on the same light guide medium; the incident laser enters the light guide medium and is reflected on the incident reflection surface for the first time, the primary laser formed after the first reflection advances in the light guide medium, the advanced primary laser is reflected on the emergent reflection surface for the second time, and the emergent laser after the second reflection leaves the light guide medium to obtain emergent laser; the advancing direction of the emergent laser is vertical to the reflecting layer of the fluorescent body;

the emergent laser is subjected to fluorescence excitation treatment on a phosphor to generate primary composite light;

and carrying out convergence treatment on the primary composite light to form secondary composite light.

By adopting the technical scheme, the illumination function is realized by utilizing the incident laser to generate composite light; after the obtained incident laser is subjected to reflection treatment, the light paths of the obtained emergent laser and the incident laser are not superposed any more; in the process of reflection treatment, incident laser needs to be reflected twice to obtain emergent laser, and after the two reflections, the angle between the incident laser and the emergent laser can be selected within the angle range of 0-180 degrees. The reflecting layer of the fluorescent body is vertical to the advancing direction of the emergent laser, so that the whole primary composite light synthesized by the reflecting layer of the fluorescent body can be vertical to the reflecting layer according to the light reflecting law, part of the emergent laser which is not excited by the fluorescent body can return in the original way, and the emergent laser which is not excited by the fluorescent body passes through the emergent reflecting surface to be emitted to the incident reflecting surface and then returns to the laser, thereby reducing the leakage of the laser stray light and reducing the laser stray light in the secondary composite light. When the angle between the incident laser and the emergent laser reaches 180 degrees, the advancing directions of the incident laser, the emergent laser and the primary composite light are parallel to each other, so that the device for generating the incident laser and the device for realizing the reflection processing can be arranged along the advancing direction of the incident laser approximately, the deviation of a hardware structure caused by the deflection angle generated between the incident laser and the emergent laser is reduced, and the complexity of the hardware structure is simplified. The primary composite light generated on the phosphor passes through the reflective layer according to the optical reflection law and then travels in the vertical direction of the reflective layer. Since the beam angle of the primary composite light synthesized on the phosphor is large and the light intensity distribution curve is distributed in a lambertian shape, the beam angle of the primary composite light can be reduced by the convergence processing, so that the beam of the secondary composite light is more concentrated. In summary, the present application has the effect of reducing the emergence of the laser stray light along with the secondary composite light.

Optionally, a light control channel is established, a light inlet and a light outlet are arranged at two ends of the light control channel, and the incident laser enters from the light inlet, passes through the light control channel, and exits from the light outlet.

By adopting the technical scheme, the arrangement of the light control channel enables incident laser to move forwards only along the light control channel, and laser stray light deviating from the light control channel cannot pass through the light control channel, so that the laser stray light in the incident laser is limited in the light control channel, and the direction consistency of the incident laser is improved.

In a second aspect, the present application provides a light path structure for exciting a fluorescent medium with laser to generate composite light, which adopts the following technical scheme:

an optical path structure for exciting a fluorescent medium by using laser to generate composite light, comprising:

a laser for generating incident laser light;

the light guide column comprises an incident reflecting surface and an emergent reflecting surface, and the incident reflecting surface and the emergent reflecting surface are integrally arranged on the same light guide medium; the incident laser can be reflected on the incident reflecting surface for the first time, the primary laser formed after the primary reflection advances in the light guide medium, and the advanced primary laser reflects on the emergent reflecting surface for the second time and then leaves the light guide medium to obtain emergent laser;

the fluorescent body comprises a reflecting layer for generating primary composite light by carrying out fluorescence excitation processing on emergent laser, and the advancing direction of the emergent laser is vertical to the reflecting layer of the fluorescent body;

and the emergent lens group is used for carrying out convergence treatment on the primary composite light to form secondary composite light.

By adopting the technical scheme, the laser can generate incident laser, and the light guide column is taken as an integral structural part, so that the structure is simple, and the problem of complex light path structure is solved; on the other hand, the laser beam guiding device can play a role in guiding the change of the direction of the incident laser beam; in the process of advancing the incident laser and the emergent laser, the incident laser can be conducted along the light guide column because the light guide medium is higher than the refractive index of the surrounding air, so that the generation of laser stray light can be reduced or even eliminated. When the emitted laser is vertically irradiated on the fluorescent body, part of the emitted laser is converted into incoherent wavelength light through the fluorescent body, part of the emitted laser is reflected through the gaps and the surface of the fluorescent body to become incoherent wave light without laser speckle, and the incoherent wavelength light and the incoherent wave light are mixed to form primary composite light of incoherent waves. The primary composite light is reflected on the reflecting layer, so that the primary composite light advances along the direction opposite to the advancing direction of the emergent laser, and the laser can emit light only through the diffuse reflection of the fluorescent body and the diffuse reflection of the reflecting layer, so that the coherence of the incident laser is weakened or even completely removed, harmful laser speckles are reduced or even eliminated in light spots of the primary composite light, and the light intensity distribution of the light spots of the primary composite light is more uniform; meanwhile, the risk of directly leaking laser through gaps in the fluorescent medium in the related art is reduced or even avoided. On one hand, the emergent lens group plays a role in reducing the beam angle of the primary composite light, so that the beam of the secondary composite light is more concentrated. Therefore, the method and the device have the function of reducing the laser stray light mixed in the secondary composite light, and the brightness of the secondary composite light is improved.

Optionally, an antireflection film is disposed on the incident window surface and/or the exit window surface of the light guide column, and the working wavelength of the antireflection film is 400nm to 700 nm.

By adopting the technical scheme, the antireflection film can reduce the reflected light of the light guide column on the incident window surface and the exit window surface, and reduce the light reflection loss, thereby increasing the light transmission amount of the light guide column and achieving the purpose of reducing the stray light in the light path structure.

Optionally, the incident reflection surface and/or the exit reflection surface of the light guide column are/is provided with a reflection film, and the working wavelength of the reflection film is 400nm to 700 nm.

By adopting the technical scheme, the reflecting film can improve the reflectivity of the light guide column on the incident reflecting surface and the emergent reflecting surface, and reduce the light loss or light leakage of incident laser on the incident reflecting surface or the emergent reflecting surface.

Optionally, the light guide pillar further includes:

a medium interface comprising an entrance window face, an exit window face, and a light propagation side face; the incident laser is emitted to the incident reflecting surface from the incident window surface, and the emergent laser is emitted to the exit window surface from the emergent reflecting surface;

the light guide side surface is arranged on the surface of the light guide column except the incident reflecting surface, the emergent reflecting surface and the medium interface;

and light absorption layers for absorbing stray light inside the light guide column are arranged on the light propagation side face and the light guide side face.

By adopting the technical scheme, the structure of the light guide column integration can simplify the inside of the light path structure, and the light guide column can guide incident laser to reach the emergent lens group, so that the use of the supporting structure is reduced.

Optionally, the light source further comprises a light control tube, two ends of the light control tube are respectively provided with a light inlet and a light outlet, and the light inlet and the light outlet are communicated with each other to form a light control channel; the incident laser can be incident from the light inlet, passes through the light control channel and then exits from the light outlet; the light inlet of the light control tube faces the laser, and the light outlet faces the entrance window face of the light guide column.

By adopting the technical scheme, the light control tube can control the incident laser to advance in the light control channel, and the laser stray light is absorbed after touching the inner wall of the light control channel, so that the leakage of the laser stray light of the incident laser can be reduced.

Optionally, the light control tube is provided with a light absorbing coating on an inner side wall of the light control channel.

By adopting the technical scheme, the light absorption coating can improve the light absorption rate of the inner wall of the light control channel, so that the laser stray light deviating from the integral advancing direction of the incident laser meets the light absorption coating and is absorbed, the laser stray light is difficult to separate from the light outlet of the light control tube, and the leakage of the laser stray light is further reduced.

Optionally, the light source further comprises a light diffusion sheet for atomizing incident laser light, and the light diffusion sheet is arranged between the laser and the light control pipe.

By adopting the technical scheme, when the incident laser passes through the light diffusion sheet, the incident laser is diffused; the light intensity curve of laser is Gaussian distribution, the incident laser is through the light diffusion piece after, the whole of the incident laser that is located the diffusion angle can be followed the light accuse passageway and is incited to the light guide pole, the partial laser stray light that is located outside the diffusion angle can be absorbed under the restriction of accuse light pipe, consequently the light diffusion piece can be on the one hand with the even atomizing of the light beam of incident laser, make the energy distribution of the emergent laser of shining on the fluorophor more even, help promoting the life-span and the utilization ratio of fluorophor, on the other hand sets up between accuse light pipe and laser instrument, can realize the effective control of laser stray light.

Optionally, a heat conducting substrate is disposed on a side of the phosphor facing away from the reflective layer, and a heat conductivity coefficient of the heat conducting substrate is not less than 15W/m.k.

By adopting the technical scheme, the fluorescent body is arranged on the heat conduction substrate and is directly connected on the heat conduction substrate. Therefore, heat generated by the fluorescent body during working can be efficiently conducted to the heat conducting substrate, so that the light efficiency and the service life of fluorescent powder in the fluorescent body can be effectively improved, and the problem that no direct heat dissipation medium exists on the back of the highest temperature point of the fluorescent body in a light path structure in the related technology is solved. In addition, the primary composite light projected towards the heat conduction substrate is reflected by the reflection layer of the heat conduction substrate, and the luminous flux of the fluorescent body is improved.

In summary, the present application includes at least one of the following beneficial technical effects:

1. compared with the composite light generated by the optical path structure in the related technology, the laser light path structure can effectively reduce the harm of direct laser light leakage. Because the laser of the application can emit light only through the diffuse reflection of the fluorescent body and the diffuse reflection of the reflecting layer, the coherence of the laser is weakened or even completely removed, and the emergent secondary composite light almost has no laser speckle.

2. The structure of the combination of the light guide column and the light control tube can effectively control the leakage of the laser, so that the stray light of the laser is difficult to mix in the light path of the primary composite light.

3. Since the phosphor is provided with the heat conductive substrate, the back surface of the hottest spot thereof directly contacts the metal heat conductor. Therefore, heat generated by the fluorescent body during working can be efficiently conducted to the heat conducting substrate, the heat dissipation performance of the fluorescent body is improved, the luminous efficiency of fluorescent powder in the fluorescent body is effectively improved, and the service life of the fluorescent powder is effectively prolonged.

4. After the incident laser is diffused by the light diffusion sheet, the incident laser can be limited to advance in the light control tube, and the laser stray light touching the inner wall of the light control tube can be absorbed by the inner wall of the light control channel, so that the laser stray light is not easy to leak outwards.

5. The light guide column can solve the problem that two reflectors in the related art cause complex supporting structures, can guide incident laser to change the direction of a light path, enables the incident laser to irradiate the emergent lens group without an additional supporting component, and is simple in structure, small and compact in size and capable of reducing cost.

Drawings

Fig. 1 is a light path diagram of laser illumination of the related art.

FIG. 2 is a flow chart of a method for generating composite light using a laser to excite a fluorescent medium according to an embodiment of the present application.

Fig. 3 is an optical path diagram of an optical path structure for generating composite light by using laser according to an embodiment of the present application.

FIG. 4 is a schematic structural diagram of a light control tube according to an embodiment of the present application (showing the light inlet).

Fig. 5 is a schematic structural diagram of a light control tube according to an embodiment of the present application (showing light outlets).

Fig. 6 is a schematic view of the overall structure (the side facing the medium exchanging surface) of a laser-illuminated light guide pillar structure according to an embodiment of the present application.

FIG. 7 is a schematic view of a light guide bar structure (back-to-media interface) according to an embodiment of the present application.

FIG. 8 is a schematic view of a light guide bar structure (facing the media interface) according to an embodiment of the present disclosure.

FIG. 9 is a schematic diagram of a light path advancing in a light guide structure according to an embodiment of the present application.

FIG. 10 is a schematic illustration of fluorescence excitation processing according to an embodiment of the present application.

Fig. 11 is a cross-sectional view of an optical path structure for generating composite light using laser light according to an embodiment of the present application.

Fig. 12 is a schematic diagram of the optical path structure of the laser in comparative example 1 in the related art.

Fig. 13 is a schematic diagram of the optical path structure of the laser in comparative example 2 in the related art.

Fig. 14 is a schematic diagram of the optical path structure of the laser in comparative example 3 in the related art.

Description of reference numerals:

1. a laser;

2. a shaping lens;

3. a light diffusing sheet;

4. a light control pipe; 41. a light inlet; 42. a light outlet; 43. a light absorbing coating;

5. a light guide pillar;

501. a media exchange surface; 5011. an entrance window face; 5012. an exit window surface; 5013. a light propagation side;

502. a reflective side; 5021. an incident reflecting surface; 5022. a reflection surface is emitted;

503. a light guide side surface;

51. a reflective film; 52. an anti-reflection film; 53. a light absorbing layer;

6. a phosphor; 61. a reflective layer; 62. a heat conductive substrate;

7. an exit lens group; 71. a main lens; 711. an inner reflective mirror surface; 72. a large lens;

811. a condenser lens; 812. a first reflective mirror; 813. a second reflective mirror; 814. a first diffusion sheet; 815. a second diffusion sheet;

91. a fluorescent medium; 92. a highly thermally conductive body.

Detailed Description

The present application is described in further detail below with reference to figures 1-14.

The embodiment of the application provides a method for exciting a fluorescent medium to generate composite light by using laser.

Referring to fig. 2, a method for exciting a fluorescent medium to generate composite light by using laser, wherein the incident laser may be a laser in a blue waveband of 430nm to 475nm, a laser in a visible light waveband of 475nm to 700nm, or an ultraviolet wave

The incident laser of the section is in Gaussian distribution, the range of the parallel beam angle is 0.5-1 degrees, and the range of the vertical beam angle is-1 degrees.

After the incident laser is obtained, the incident laser is converged, specifically, the incident laser can be converged by a shaping lens 2, the shaping lens 2 is a plano-convex lens with one surface being a free-form surface or a spherical surface and the other surface being a plane, and in another embodiment, the shaping lens 2 can also be a biconvex lens with both surfaces being spherical surfaces or free-form surfaces. The converged incident laser light advances in a convergent manner.

The intensity of the converged incident laser light is concentrated at the center of the beam and is slightly lower at the edges of the beam. Since such high energy irradiation on the phosphor 6 may cause local damage to the phosphor 6, it is necessary to atomize the incident laser light, and specifically, the light diffusion sheet 3 may be used, and one surface of the light diffusion sheet 3 is coated with the antireflection film 52, and the other surface is processed by etching or frosting, so that the surface of the light diffusion sheet 3 becomes rough. Incident laser light enters from the side of the light diffusion sheet 3 provided with the antireflection film 52 and exits from the side of the light diffusion sheet 3 roughened, and the half diffusion angle of the incident laser light is 0.5-3 degrees according to the roughness of the roughened side of the light diffusion sheet 3, and the light intensity distribution is uniform.

A light control channel is established on the advancing path of the incident laser, two ends of the light control channel are respectively provided with a light inlet 41 and a light outlet 42, and the incident laser enters from the light inlet 41, passes through the light control channel and then exits from the light outlet 42. The light control channel can allow the main beam of the incident laser to pass through, and the laser stray light of which the edge of the incident laser deviates from the advancing direction of the main beam is trapped in the light control channel and is difficult to escape from the light outlet 42, so that the generation of the laser stray light can be reduced. Further, stray laser light is absorbed in the light control channel, specifically, a light absorption layer 53 is disposed in the light control channel, and the stray laser light is absorbed by most of the light absorption layer 53 after encountering the stray laser light, so that the generation of stray laser light is further reduced.

The incident laser beam is subjected to reflection processing to obtain an outgoing laser beam. Specifically, the reflection process includes establishing a reflection side 502, where the reflection side 502 includes an incident reflection surface 5021 and an emergent reflection surface 5022, and the incident reflection surface 5021 and the emergent reflection surface 5022 are integrally disposed on the same light guide medium. The surface of the light guide medium comprises an incidence window face 5011 and an exit window face 5012, incident laser enters from the incidence window face 5011 and is transmitted to the incidence reflecting face 5021 in the light guide medium to be reflected once, primary laser formed after the primary reflection moves forwards in the light guide medium, the incident laser after the forward movement performs secondary reflection on the exit reflecting face 5022, and the exit laser is obtained after the secondary reflection and is emitted out of the light guide medium.

Further, the incident laser beam enters the incident reflection surface 5021 at an angle of 45 degrees, and exits at an angle of 45 degrees from the incident reflection surface 5021 after the primary reflection according to the reflection law of light.

Further, the incident reflection surface 5021 is perpendicular to the emergent reflection surface 5022, so that when the incident laser beam after primary reflection reaches the surface of the emergent reflection surface 5022, the included angle between the incident laser beam after primary reflection and the emergent reflection surface 5022 is 45 °, and according to the reflection law of light, the included angle between the emergent laser beam after secondary reflection and the emergent reflection surface 5022 is 45 °. Since the first reflected incident laser beam is also guided in the same light guide medium from the incident emission surface to the exit reflection surface 5022, the loss of light energy is reduced. Meanwhile, the reflection, refraction or scattering of the incident laser or the emergent laser at the interface of the medium in the conversion process of the light guide medium is reduced, so that the consistency of the incident laser and the emergent laser in the advancing process is kept, and the generation of laser stray light is reduced.

The phosphor 6 is capable of converting the emitted laser light into primary composite light, the phosphor 6 includes a reflective layer 61, and the reflective layer 61 is disposed at a position perpendicular to the proceeding direction of the emitted laser light such that the emitted laser light is perpendicular to the reflective layer 61 of the phosphor 6; the emission laser light is irradiated onto the phosphor 6 to generate primary composite light, and the primary composite light is reflected by the reflection layer 61 and then travels in the direction opposite to the traveling direction of the emission laser light.

And carrying out convergence treatment on the primary composite light to form secondary composite light. Specifically, the convergence processing includes primary light condensation and secondary light condensation, the primary light condensation converges the primary composite light reflected by the reflecting layer 61 of the phosphor 6 into primary composite light with a diffusion angle of 90 ° to 150 °, and in order to further converge the light beam of the primary composite light, the secondary light condensation further converges the primary composite light, and the diffusion angle of the converged secondary composite light is 0.5 ° to 5 °, specifically 4 °, 3 °, or 2 °. By the arrangement, the light path of the emergent secondary composite light is similar to a parallel light path, so that the energy of the secondary composite light is more concentrated, and the illumination effect is better in illumination occasions requiring high power and high light intensity and long-distance illumination.

The implementation principle of the method for generating the composite light by exciting the fluorescent medium by using the laser in the embodiment of the application is as follows: the incident laser is converged, so that the beam angle of the incident laser is smaller, and the transmission of the incident laser is facilitated; the light beam of the incident laser is in Gaussian distribution, and after atomization treatment, the central light intensity of the light beam is dispersed, so that the light intensity distribution of the laser is more uniform; the incident beam after atomization passes through the light control channel, and the laser stray light is intercepted in the light control channel; reflection processing is carried out between the incident laser and the emergent laser, so that the advancing directions of the incident laser and the emergent laser are opposite; the emergent laser is vertically irradiated on the fluorescent body 6, primary composite light is synthesized, and the primary composite light is converged to form secondary composite light. The method can reduce or even eliminate the laser stray light in the secondary composite light, thereby improving the safety of laser illumination.

The embodiment of the application also discloses a light path structure for exciting the fluorescent medium by using laser to generate composite light.

Referring to fig. 3, an optical path structure for generating composite light by exciting a fluorescent medium with laser includes a laser 1, a shaping lens 2, a light diffusion sheet 3, a light control tube 4, a light guide column 5, a phosphor 6, and an exit lens group 7. Wherein the laser 1 generates incident laser light. The wavelength of the incident laser can be ultraviolet band, blue band laser of 430 nm-475 nm or band capable of exciting the fluorescent powder to emit light.

Referring to fig. 3, the shaping lens 2 may be a plano-convex lens having one plane and the other plane being a free-form surface or a spherical surface. In another embodiment, the shaping lens 2 may be a biconvex lens with both sides spherical. After the incident laser light passes through the shaping lens 2, the light diffusion angle of the incident laser light is converged, and the focal point of the incident laser light can be focused on the fluorescent material 6. Further, the shaping lens 2 may be made of glass, quartz, acrylic, or other transparent optical material resistant to high temperature.

Referring to fig. 3, the light diffusion sheet 3 may be made of glass, acryl or other materials, and one surface of the light diffusion sheet 3 is processed by etching, sanding, etc. to make one surface of the light diffusion sheet 3 rough; the other side of the light diffusion sheet 3 is provided with an antireflection film 52, and the antireflection film 52 may be plated on the surface of the light diffusion sheet 3. The light passing through the light diffusion sheet 3 can be diffused and reflected on the rough surface so that the diffusion angle of the light is increased.

The light diffusion sheet 3 is provided coaxially with the shaping lens 2 so that the incident laser light emitted from the shaping lens 2 enters from the side of the light diffusion sheet 3 provided with the antireflection film 52 and exits from the rough surface, and the half diffusion angle of the incident laser light is diffused in the range of 0.5 ° to 4 °. With the arrangement, the light intensity of the center of the incident laser beam is dispersed, so that the light intensity of the incident laser beam is distributed more uniformly. Further, the working wavelength of the antireflection film 52 is 400nm to 700 nm. The antireflection film 52 can pass visible light with a wavelength in the range of 400nm to 700nm, and has high applicability.

Referring to fig. 4 and 5, the light control tube 4 is tubular, and two ends of the light control tube 4 are respectively provided with a light inlet 41 and a light outlet 42, and the light inlet 41 and the light outlet 42 are communicated with each other to form a light control channel. Further, the inner wall of the light control channel is provided with a light absorption coating 43, the light absorption coating 43 is a black material with a rough surface, specifically, the light absorption coating can be a light absorption paint formed by coating sandblasted anode blackening on the surface of the light guide column 5, and the light absorption coating can also be realized by spraying a composite carbon layer or flocking and other methods.

Referring to fig. 3, after the incident laser is diffused by the light diffusion sheet 3, most of the laser is confined to advance in the light control tube 4, and the stray laser light hitting the inner wall of the light control tube 4 is absorbed by the inner wall of the light control tube 4, so that the stray laser light is difficult to leak.

With continued reference to fig. 3, the light inlet 41 of the light control tube 4 is disposed toward the roughened surface of the light diffusion sheet 3, and the light control channel of the light control tube 4 is disposed coaxially with the light diffusion sheet 3. The incident laser light can enter from the light inlet 41, pass through the light control channel, and exit from the light outlet 42. The stray laser light deviating from the main beam of the incident laser is difficult to emit out of the light control tube 4 under the blocking of the inner wall of the light control tube 4, and most of the stray laser light is absorbed by the light control tube 4 and converted into heat under the absorption of the light absorption coating 43, so that the stray laser light existing in the light path structure is reduced.

Referring to fig. 4 and 5, further, the light-controlling tube 4 is conical, wherein the diameter of the light inlet 41 is larger than that of the light outlet 42, a supporting member is further disposed at one end of the light outlet 42 of the light-controlling tube 4, the supporting member is composed of two supporting blocks, the two supporting blocks are disposed opposite to each other at the edge of the light outlet 42, and the supporting blocks and the light-controlling tube 4 are integrally formed.

Referring to fig. 3 and 6, the light guiding pillar 5 is a quadrangular prism, the bottom surface of the quadrangular prism is an isosceles trapezoid, the side surface between one inclined edge of the two isosceles trapezoids opposite to each other is an incident reflection surface 5021, and the side surface between the other inclined edge of the two isosceles trapezoids opposite to each other is an emergent reflection surface 5022; the side surface between the opposite lower bottom edges of the two isosceles trapezoids is a medium exchange surface 501. The media exchange face 501 includes an entrance window face 5011, an exit window face 5012, and a light propagation side face 5013, wherein the entrance window face 5011 is disposed adjacent to the entrance reflective face 5021, the exit window face 5012 is disposed adjacent to the exit reflective face 5022, and the light propagation side face 5013 is disposed between the entrance window face 5011 and the exit window face 5012. The light guide pillar 5 has light guide side surfaces 503 except for the incident reflection surface 5021, the exit reflection surface 5022, and the medium exchanging surface 501.

Referring to fig. 3 and 6, the incident window of the light guide pillar 5 faces the light outlet 42 of the light control pipe 4, and the two support blocks of the light control pipe 4 are respectively abutted against the light guide side surfaces 503 on both sides of the medium exchange surface 501 of the light guide pillar 5, so that the light control pipe 4 has supporting and limiting effects on the light guide pillar 5.

Referring to fig. 7, further, the entrance window face 5011 and the exit window face 5012 of the light guide pillar 5 are both coated with an antireflection film 52, and the operating wavelength of the antireflection film 52 is 400nm to 700 nm.

Referring to fig. 7 and 8, a light absorbing layer 53 is further provided on the light propagation side 5013 and the light guide side 503. The light absorbing layer 53 may be attached to the surfaces of the light propagation side 5013 and the light guide side 503 by means of coating or plating. The light absorbing layer 53 can absorb stray light inside the light guide column 5, thereby reducing the generation of laser stray light.

Referring to fig. 6 and 7, the incident reflection surface 5021 and the emergent reflection surface 5022 of the light guide column 5 are integrally disposed on a same light guide medium, which may be glass, acrylic, quartz material or other transparent high temperature resistant light guide medium. Further, the incident reflection surface 5021 and the exit reflection surface 5022 of the light guide column 5 are both coated with a reflection film 51, and the operation wavelength of the reflection film 51 is 400nm to 700 nm. In another embodiment, the surfaces of the incident reflection surface 5021 and the emergent reflection surface 5022 are not coated with films, but polished to make the surfaces of the incident reflection surface 5021 and the emergent reflection surface 5022 smooth and flat by polishing, so that the laser can generate total reflection of visible light when the incident angle of the incident reflection surface 5021 and the emergent reflection surface 5022 is greater than the critical angle of total reflection.

Referring to fig. 6, further, an included angle between the oblique side of the isosceles trapezoid and the bottom side is 45 °, and it is also easy to know that an included angle between the incident reflection surface 5021 and the emergent reflection surface 5022 is a right angle. Therefore, when the incident laser enters the light guide column 5 perpendicular to the incident window face 5011, the incident laser can form an angle of 45 degrees with the incident reflecting face 5021, so that the incident laser is incident into the light guide medium and is reflected once on the incident reflecting face 5021, and the incident laser can continue to advance along the light guide medium. When the incident laser beam having undergone the primary reflection is also emitted from the incident reflection surface 5021 at 45 °, reaches the emission reflection surface 5022, and is reflected for the second time to obtain the emission laser beam, the incident laser beam having undergone the primary reflection is also 45 ° to the emission reflection surface 5022, and the emission laser beam is also 45 ° to the emission reflection surface 5022. The exit laser light is vertically emitted from the exit reflecting surface 5022 toward the exit window surface 5012. Since the entrance window face 5011 and the exit window face 5012 are on the same plane, the traveling direction of the outgoing laser light is opposite to that of the incident laser light.

Referring to fig. 6 and 9, the light guide pole 5 can solve the complicated support structure of the two mirrors in the related art. The light guide 5 itself is also a structural member, and can guide the incident laser to turn 180 ° to form the outgoing laser, and project the outgoing laser onto the main lens 71 without an additional support member. The incident laser light is turned 180 degrees by the light guide pillar 5 when passing through the primary composite light. The optical material of the light guide 5 is excellent in guiding the incident laser light to the phosphor 6 and controlling the escape of the stray light of the laser light from the light guide 5, so that the stray light of the laser light is less likely to be mixed into the optical path of the primary composite light. So that harmful laser speckles are not easily mixed in the secondary composite light. The light guiding side 503 of the light guiding pole 5 is coated with a black light absorbing material, so that the light guiding pole 5 has almost no side leakage laser stray light.

Referring to fig. 10, the phosphor 6 may be a ceramic phosphor sheet or a glass phosphor sheet containing phosphor, and the phosphor 6 contains phosphor crystal particles capable of converting a blue laser beam of 430nm to 475nm into yellow light. One surface of the fluorescent body 6 is provided with a heat conducting substrate 62, and the heat conducting substrate 62 has a heat conductivity not less than 15W/m.k, and the heat conducting substrate 62 may be a mirror aluminum substrate, an alumina substrate, a mirror silver substrate, silver, aluminum, or other heat conducting substrate 62 having a high reflection medium and having a reflection function. The mirror aluminum substrate is an aluminum substrate with white light reflectivity of more than 85%, the mirror silver substrate is a silver-plated aluminum substrate with white light reflectivity of more than 95%, and the alumina substrate is an alumina ceramic or alumina single crystal substrate plated with a reflecting film 51, with reflectivity of more than 95%. The heat conductive substrate 62 and the phosphor 6 are fixed by sintering, bonding, or the like. The surface of the heat conductive substrate 62 is surface-treated to have a visible light reflection function, and the reflectance thereof is 76% or more. A reflecting layer 61 is formed at the junction of the fluorescent body 6 and the heat conductive substrate 62, and the traveling direction of the emitted laser light is perpendicular to the reflecting layer 61 of the fluorescent body 6.

Referring to fig. 10 and 11, taking blue laser as an example of the emitted laser, the emitted laser irradiates the phosphor 6, most of the emitted laser is converted into yellow light with incoherent wavelength by the phosphor, and the incident laser of a part of blue coherent wave is reflected by the gap and the surface diffusion inside the phosphor 6 to become incoherent wave blue light, which does not include laser spots with strong light intensity. The yellow and blue light mixes, and the action of the reflective layer 61 forms the primary composite light, which is on the blackbody radiation curve, and thus the primary composite light is white light. Since the emergent laser can emit light after the diffuse reflection of the fluorescent body 6 and the reflection of the reflecting layer 61, the coherence of the emergent laser is weakened or even completely removed, so that the light spots of the composite light hardly contain harmful laser spots, and the light intensity distribution is more uniform. At the same time, the risk of direct laser leakage through the gaps between the phosphors in the phosphor 6 of the related art is reduced or even avoided. In addition, since the phosphor 6 is directly attached to the heat conductive substrate 62, there is no intermediate transition of sapphire sheets, and the heat generated by the phosphor 6 during operation can be efficiently conducted to the heat sink. The luminous efficiency and the service life of the fluorescent powder in the fluorescent sheet are effectively improved, and the problem of difficulty in heat dissipation of a white light path structure in the related technology is solved.

Referring to fig. 3 and 10, the exit lens group 7 includes a main lens 71 and a large lens 72, the main lens 71 is a plano-convex lens having one surface thereof being a flat surface and the other surface thereof being a free-form surface or a spherical surface, the primary composite light enters from one surface of the main lens 71 and exits from the other surface, and the plano-convex lens has a function of converging light rays, so that the primary composite light rays on the phosphor 6 are converged by the main lens 71, and a diffusion angle of the primary composite light rays is between 90 ° and 150 ° depending on a curvature limit of the main lens 71. The large lens 72 can further converge the primary composite light, the large lens 72 is a biconvex lens, and can converge the light of the primary composite light passing through the main lens 71 to form secondary composite light, so that the diffusion angle of the secondary composite light is 0.5-3 degrees. Furthermore, the surfaces of the main lens 71 and the large lens 72 are coated with the antireflection film 52 with the working wavelength of 400 nm-700 nm, so that the transmittance of light rays can be increased. Further, the main lens 71 or the large lens 72 may be made of glass, quartz, acrylic, or other transparent optical material resistant to high temperature.

The implementation principle of the optical path structure for generating the composite light by exciting the fluorescent medium with the laser in the embodiment of the application is as follows: referring to fig. 11, a laser 1 generates incident laser light, and the incident laser light passes through a shaping lens 2, a light diffusion sheet 3, a light control tube 4, a light guide pillar 5, a main lens 71, a phosphor 6, the main lens 71, and a large lens 72 in this order; the shaping lens 2 achieves convergence forward of incident laser, the light diffusion sheet 3 achieves atomization of the incident laser and uniform light intensity dispersion of incident laser beams, the light control tube 4 can reduce or even eliminate stray light, the light guide column 5 achieves 180-degree steering of the incident laser and the emergent laser, the fluorescent body 6 achieves conversion of the emergent laser into primary composite light, the primary composite light is subjected to preliminary convergence of a diffusion angle by the main lens 71, and the primary composite light subjected to preliminary convergence of the diffusion angle is further subjected to convergence of the diffusion angle by the large lens 72. The purpose that harmful laser speckles are hardly contained in the emergent secondary composite light is achieved by absorbing and eliminating the laser stray light in the light path structure, the safety of laser illumination is greatly improved, and the brightness of the laser illumination is improved.

Comparative example 1:

referring to fig. 12, a laser light path structure is composed of a laser 1, a condenser lens 811, a light diffusion sheet 3, a first reflective mirror 812, a second reflective mirror 813, a fluorescent medium 91, a highly thermally conductive body 92, a main lens 71, and a large lens 72. The laser light is emitted from the laser 1, passes through the condenser lens 811 and the light diffusion sheet 3, passes through the first reflecting mirror 812, reaches the second reflecting mirror 813, and is irradiated onto the medium 91 containing the fluorescent material. The blue laser of the partial coherent wave is converted into yellow light of the incoherent wave through the fluorescent powder, the blue laser of the partial coherent wave is reflected through the gaps of the fluorescent crystals and the surface diffuse reflection to become blue light of the incoherent wave, and the blue light of the incoherent wave is transmitted out through the gaps of the fluorescent powder particles. The yellow light of incoherent wavelength and the blue light of incoherent wave are mixed to form white light of incoherent wave. The high heat conduction main part 92 surface reflects light, and the white light meets high heat conduction main part 92 after-reflection, because the laser need pass through the diffuse reflection of fluorescence medium 91 and the diffuse reflection of base plate just can the emergent white light, weakens and even thoroughly removes the laser coherence, and the white light facula of emergent does not have harmful spot and more even. Meanwhile, the risk of directly leaking laser light from the gap of the fluorescent medium 91 is reduced or even avoided. In addition, since the fluorescent medium 91 is directly seated on the high thermal conductive body 92, heat generated from the phosphor 6 during operation can be efficiently conducted to the heat sink. The luminous efficiency and the service life of the fluorescent powder in the fluorescent sheet are effectively improved.

However, in the white light path structure in comparative example 1, there is a problem of stray light of laser from the object to be illuminated due to a defect in the design of the light path. When the laser light path penetrates through the light diffusion sheet 3, part of laser is reflected and scattered by the diffusion surface and projected onto the white light path, so as to form laser stray light in the white light emergent light path. The energy of the laser stray light reflection and scattering light is related to the diffusion angle, and the larger the diffusion angle is, the larger the energy is. Specifically, the laser stray light may be 1% to 5% of the total laser beam energy. The stray laser light is projected onto the surface of the illuminated object through the large lens 72, so that harmful stray laser light is mixed in the white light spot.

Comparative example 2:

referring to fig. 13, the difference from comparative example 1 is that a light diffusion sheet 3 of a laser light path structure is disposed between a condensing lens 811 and a first reflective mirror 812. When the laser light passes through the light diffusion sheet 3, the laser beam is diffused and the laser light is gaussian-distributed. The main laser beam within the diffusion angle is projected onto the fluorescent body 6 according to the designed optical path; however, the edge laser outside the diffusion angle is not effectively controlled and converged on the phosphor 6 by the optical device in the optical path in the process of advancing in the air, so as to form the laser stray light in the cavity of the optical path structure. Part of the stray laser light enters the white light path and is projected to the surface of an object to be illuminated through the large lens 72, and harmful stray laser light in a white light spot is generated. In the same way, in comparative example 2, the light path needs to be changed by the first reflector and the second reflector, and the two parts need to be supported by the structural member respectively, so that the structure of the white light path is complex and the manufacturing cost is high.

Comparative example 3:

referring to fig. 14, the difference from embodiment 1 is that a laser light path structure is composed of a laser 1, a condenser lens 811, a first diffusion sheet 814, a main lens 71, a fluorescent medium 91, a high thermal conductive body 92, a second diffusion sheet 815 and a large lens 72. The main lens 71 is a plano-convex lens, an inner reflecting mirror 711 is arranged on one side of a convex surface of the main lens 71, laser emitted by the main lens 71 in the laser 1 sequentially penetrates through the condensing lens 811 and the first diffusion sheet 814, the laser enters from one side of a plane of the main lens 71, irradiates the inner reflecting mirror 711 and emits from the inner reflecting mirror 711, the direction of the laser is turned, and further irradiates the fluorescent medium 91, and the laser is subjected to energy conversion after passing through the fluorescent medium 91 to synthesize white light. The white light is converged by the main lens 71 and emitted, and is diffused by the second diffusion sheet 815 and emitted from the large lens 72.

However, when the laser light reaches the fluorescent material 6, the inner reflecting mirror 711 forms an angle with the surface of the fluorescent medium 91, so that the incident angle of the laser light is not perpendicular to the fluorescent medium 91. With this arrangement, the incident laser light is reflected on the surface of the fluorescent medium 91, and this part of the reflected laser light can pass through the main lens 71 and irradiate the large lens 72 through the main lens 71, and further be projected onto the surface of the irradiated object, and harmful stray laser light is generated.

The above embodiments are preferred embodiments of the present application, and the protection scope of the present application is not limited by the above embodiments, so: all equivalent changes made according to the structure, shape and principle of the present application shall be covered by the protection scope of the present application.

Claims

1. A method for exciting a fluorescent medium to generate composite light by using laser is characterized in that: the method comprises the following steps:

acquiring incident laser;

the incident laser is subjected to reflection processing to obtain emergent laser, wherein the reflection processing comprises establishing an incident reflection surface (5021) and an emergent reflection surface (5022), and the incident reflection surface (5021) and the emergent reflection surface (5022) are integrally arranged on the same light guide medium; the incident laser enters a light guide medium and is reflected on an incident reflection surface (5021) for the first time, the primary laser formed after the first reflection advances in the light guide medium, the advanced primary laser reflects on an emergent reflection surface (5022) for the second time, and the emergent laser after the second reflection leaves the light guide medium to obtain emergent laser; the advancing direction of the emitted laser is vertical to the reflecting layer (61) of the fluorescent body (6);

the emergent laser is subjected to fluorescence excitation processing on a fluorescent body (6) to generate primary composite light, wherein the fluorescent body (6) is provided with a reflecting layer (61) for reflecting the primary composite light;

2. The method of claim 1, wherein the laser excites the fluorescent medium to produce composite light, and the method comprises: and establishing a light control channel, wherein a light inlet (41) and a light outlet (42) are arranged at two ends of the light control channel, and the incident laser enters from the light inlet (41), passes through the light control channel and then exits from the light outlet (42).

3. A light path structure for exciting a fluorescent medium to generate composite light by utilizing laser is characterized in that: the method comprises the following steps:

a laser (1) for generating incident laser light;

the light guide column (5), the incident laser gets the emergent laser through the light guide column (5), the light guide column (5) includes incident reflecting surface (5021) and emergent reflecting surface (5022), the incident reflecting surface (5021) and the emergent reflecting surface (5022) are integrally arranged on the same light guide medium; the incident laser enters a light guide medium and is reflected on an incident reflection surface (5021) for the first time, the primary laser formed after the first reflection advances in the light guide medium, the advanced primary laser reflects on an emergent reflection surface (5022) for the second time, and the emergent laser after the second reflection leaves the light guide medium to obtain emergent laser;

the fluorescent body (6) is used for generating primary composite light by fluorescence excitation processing of emergent laser, the fluorescent body (6) comprises a reflecting layer (61), and the advancing direction of the emergent laser is perpendicular to the reflecting layer (61) of the fluorescent body (6);

and the emergent lens group (7) is used for carrying out convergence treatment on the primary composite light to form secondary composite light.

4. The optical path structure for generating composite light by exciting a fluorescent medium with laser light according to claim 3, wherein: the incident window face (5011) and/or the exit window face (5012) of the light guide column (5) are/is provided with an antireflection film (52), and the working wavelength of the antireflection film (52) is 400 nm-700 nm.

5. The optical path structure for generating composite light by exciting a fluorescent medium with laser light according to claim 3, wherein: the incident reflection surface (5021) and/or the emergent reflection surface (5022) of the light guide column (5) are/is provided with a reflection film (51), and the working wavelength of the reflection film (51) is 400 nm-700 nm.

6. The optical path structure for generating composite light by exciting a fluorescent medium with laser light according to claim 3, wherein: the light guide pillar (5) further comprises:

a dielectric interface comprising an entrance window face (5011), an exit window face (5012), and a light propagation side face (5013); the incident laser beam is emitted from the incident window surface (5011) to the incident reflecting surface (5021), and the emergent laser beam is emitted from the emergent reflecting surface (5022) to the exit window surface (5012);

the light guide side surface (503) is arranged on the surface of the light guide column (5) except the incident reflection surface (5021), the emergent reflection surface (5022) and the medium interface;

light absorption layers (53) for absorbing stray light inside the light guide column (5) are arranged on the light propagation side face (5013) and the light guide side face (503).

7. The optical path structure for generating composite light by exciting a fluorescent medium with laser light according to claim 6, wherein: the light control tube is characterized by further comprising a light control tube (4), wherein a light inlet (41) and a light outlet (42) are formed in two ends of the light control tube (4) respectively, and the light inlet (41) and the light outlet (42) are communicated with each other to form a light control channel; the incident laser can be incident from the light inlet (41), passes through the light control channel and then exits from the light outlet (42); the light inlet (41) of the light control tube (4) faces the laser (1), and the light outlet (42) faces the entrance window face (5011) of the light guide column (5).

8. The optical path structure for generating composite light by exciting a fluorescent medium with laser light according to claim 7, wherein: and the light control tube (4) is provided with a light absorption coating (43) on the inner side wall of the light control channel.

9. The optical path structure for generating composite light by exciting a fluorescent medium with laser light according to claim 7, wherein: the laser device also comprises a light diffusion sheet (3) used for atomizing incident laser, wherein the light diffusion sheet (3) is arranged between the laser device (1) and the light control tube (4).

10. The optical path structure for generating composite light by exciting a fluorescent medium with laser light according to claim 3, wherein: and a heat conduction substrate (62) is arranged on one side of the fluorescent body (6) which is far away from the reflecting layer (61), and the heat conduction coefficient of the heat conduction substrate (62) is not less than 15W/m.k.