Disclosure of Invention
The embodiment of the invention provides a laser light source system and laser projection equipment, and aims to solve the technical problems that the laser light source system and the laser projection equipment are complex in structure, high in cost and low in light emitting efficiency.
In order to solve the above technical problem, the present invention provides a laser light source system, including: the device comprises a first excitation light source, a second light source, a first light uniformizing element, a second light uniformizing element, a wavelength conversion device and a light splitting and combining device;
the first excitation light source emits first blue light, and the second light source emits second blue light;
the first light homogenizing element is arranged between the first excitation light source and the light splitting and combining device, and the second light homogenizing element is arranged between the second light source and the light splitting and combining device;
the wavelength conversion device comprises a fluorescent layer and a substrate with a reflecting surface, wherein the fluorescent layer is arranged on the reflecting surface of the substrate, or the wavelength conversion device comprises the fluorescent layer, the substrate and a reflecting layer, and the reflecting layer is positioned between the substrate and the fluorescent layer;
the light splitting and combining device reflects the first blue light emitted by the first excitation light source to the fluorescent layer, and the fluorescent layer receives the first blue light emitted by the first excitation light source and performs wavelength conversion to obtain yellow excited light;
the light splitting and combining device transmits the yellow excited light and reflects the second blue light, and the yellow excited light and the second blue light are combined and output.
The present invention provides another laser light source system, including: the device comprises a first excitation light source, a second light source, a first light uniformizing element, a second light uniformizing element, a wavelength conversion device and a light splitting and combining device;
the first excitation light source emits first blue light, and the second light source emits second blue light;
the first light homogenizing element is arranged between the first excitation light source and the light splitting and combining device, and the second light homogenizing element is arranged between the second light source and the light splitting and combining device;
the wavelength conversion device comprises a fluorescent layer and a substrate with a reflecting surface, wherein the fluorescent layer is arranged on the reflecting surface of the substrate, or the wavelength conversion device comprises the fluorescent layer, the substrate and a reflecting layer, and the reflecting layer is positioned between the substrate and the fluorescent layer;
the light splitting and combining device transmits the first blue light emitted by the first excitation light source to the fluorescent layer, and the fluorescent layer receives the first blue light emitted by the first excitation light source and performs wavelength conversion to obtain yellow excited light;
the light splitting and combining device reflects the yellow excited light and transmits the second blue light, and the yellow excited light and the second blue light are combined and output.
In some of these embodiments, the thickness of the phosphor layer is 0.3mm or less.
In some embodiments, the laser light source system further includes a first scattering element disposed between the first excitation light source and the first dodging element, and the first scattering element is configured to scatter and dodge the first blue light emitted from the first excitation light source.
In some embodiments, the laser light source system further includes a second scattering element disposed between the second light source and the second dodging element, and the second scattering element is configured to scatter and dodge the second blue light emitted by the second light source.
In some embodiments, the laser light source system further includes a first reflector and a first lens group, and the first reflector and the first lens group are sequentially disposed between the first excitation light source and the light splitting and combining device.
In some embodiments, the laser light source system further includes a second reflecting mirror and a second lens group, and the second reflecting mirror and the second lens group are sequentially disposed between the second light source and the light splitting and combining device.
In some embodiments, the first excitation light source comprises a first blue laser array, a second blue laser array, and a polarization combining element; the planes of the first blue laser array and the second blue laser array are perpendicular to each other, the polarization light combination element is positioned between the first blue laser array and the second blue laser array, and the polarization light combination element is intersected with the planes of the first blue laser array and the second blue laser array; the polarization state of the light emitted by the first blue light exciter array is different from that of the light emitted by the second blue light exciter array, and the polarization light combination element combines the light emitted by the first blue light laser array and the light emitted by the second blue light laser array for output, so that the first blue light is obtained.
In some embodiments, the laser light source system further includes a third lens group disposed between the light splitting and combining device and the wavelength conversion device.
In some embodiments, the wavelength conversion device is disposed in a closed housing, the housing defines a light-passing opening, and the third lens group is disposed at the light-passing opening of the housing.
In some of these embodiments, the wavelength conversion devices are disposed in the optical path of the first blue light, movable relative to each other.
The invention also provides laser projection equipment which comprises an optical machine, a lens and the laser light source system, wherein the laser light source system is used for providing light source beams for the optical machine, the optical machine is used for modulating the light source beams and outputting the light source beams to the lens, and the lens is used for imaging and projecting the light source beams to a projection medium to form a projection picture.
Compared with the prior art, the invention at least has the following beneficial effects: the first blue light emitted by the first excitation light source passes through the wavelength conversion device to generate yellow excited light, and the yellow excited light and the second blue light emitted by the second light source are combined to form white light output; the first scattering element is used for scattering and homogenizing the first blue light, and the second scattering element is used for scattering and homogenizing the second blue light, so that the speckle phenomenon of the output white light can be effectively reduced; the first reflector, the first lens group, the second reflector, the second lens group and the third lens group are arranged, so that the space occupied by the whole laser light source system is saved, the size of the light splitting and combining device is reduced, and the size of the wavelength conversion device is reduced; by arranging the first blue laser array, the second blue laser array and the polarization light combination element, the space occupied by the first excitation light source can be reduced, and high-brightness first blue light can be obtained; the wavelength conversion device is arranged in the closed shell, so that the dustproof effect of the wavelength conversion device can be improved, the service life of the wavelength conversion device can be prolonged, and high-purity yellow excited light can be obtained; by movably arranging the wavelength conversion device and the first blue light relative to each other, the heat dissipation effect of the wavelength conversion device can be improved, and the service life of the wavelength conversion device can be further prolonged; by setting the lighting time of the first excitation light source and the second excitation light source in the same period, multicolor light can be emitted simultaneously in the same period, the light output amount per unit time is increased, or white light which is continuously output is obtained.
Detailed Description
In order to facilitate an understanding of the embodiments of the present invention, the embodiments of the present invention will be described more fully hereinafter with reference to the accompanying drawings. Preferred embodiments of the present invention are shown in the drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.
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 terminology used herein in the examples of the present invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.
In the present invention, the terms "mounted," "connected," "secured," and the like are to be construed broadly unless otherwise explicitly stated or limited. For example, the connection can be fixed, detachable or integrated; can be mechanically or electrically connected; they may be directly connected or indirectly connected through an intermediate member, or they may be connected through the inside of two elements, or they may be connected only through surface contact or through surface contact of an intermediate member. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
Further, the term "plurality" means greater than or equal to two. The terms "first," "second," and the like are used merely for distinguishing between descriptions and not intended to imply a particular structure or arrangement. The description of the terms "some embodiments," "other embodiments," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiments or examples is included in at least one embodiment or example of the invention. In the present invention, the schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, the various embodiments or examples and features of the various embodiments or examples described herein can be combined and combined by those skilled in the art without contradiction.
As shown in fig. 1, the laser light source system includes a first excitation light source 1, a second light source 2, a first light uniformizing element 31, a second light uniformizing element 32, a wavelength conversion device 4, and a light splitting and combining device 5.
The first excitation light source 1 is configured to emit first blue light 11, and the second light source 2 is configured to emit second blue light 21. The first excitation light source 1 is a laser light source, and the second light source 2 may be a laser light source, or other light sources such as an LED light source; the wavelength of the first blue light 11 may or may not be the same as the wavelength of the second blue light 21.
The first light uniformizing element 31 is disposed between the first excitation light source 1 and the light splitting and combining device 5, and the second light uniformizing element 32 is disposed between the second light source 2 and the light splitting and combining device 5. The first dodging element 31 is used for dodging the first blue light 11 emitted by the first excitation light source 1, and the second dodging element 32 is used for dodging the second blue light 21 emitted by the second excitation light source 2; the first blue light 11 and the second blue light 21 respectively subjected to the dodging process can obtain higher light energy utilization rate and more uniform illuminance. In the embodiment of the present invention, the first light uniformizing element 31 may adopt a light uniformizing rod or a fly eye lens, etc., and the second light uniformizing element 32 may adopt a light uniformizing rod or a fly eye lens, etc.
As shown in fig. 3, in some alternative embodiments, the wavelength conversion device 4 includes a fluorescent layer 41 and a substrate 42 having a reflective surface 421, the fluorescent layer 41 is disposed on the reflective surface 421 of the substrate 42; that is, the substrate 42 itself has a reflection function, and the wavelength conversion device 4 includes a two-layer structure of the fluorescent layer 41 and the substrate 42 having a reflection function. As shown in fig. 4, in some alternative embodiments, the wavelength conversion device 4 includes a fluorescent layer 41, a substrate 42, and a reflective layer 43, the reflective layer 43 being located between the substrate 42 and the fluorescent layer 41; that is, the substrate 42 itself has no reflection function and plays a role of supporting the reflection layer 43 and the fluorescent layer 41, and the wavelength conversion device 4 includes a three-layer structure including the fluorescent layer 41, the substrate 42 and the reflection layer 43.
As shown in fig. 1, the light splitting and combining device 5 has the characteristics of reflecting blue light and transmitting yellow light. In the embodiment of the present invention, the light splitting and combining device 5 may be a dichroic filter, which has the characteristics of reflecting light in a part of wavelength bands and transmitting light in another part of wavelength bands, and can achieve the purposes of reflecting blue light and transmitting yellow light.
As shown in fig. 1, 3 and 4, the light splitting and combining device 5 reflects the first blue light 11 to the fluorescent layer 41 of the wavelength conversion device 4, and the fluorescent layer 41 of the wavelength conversion device 4 receives the first blue light 11 and performs wavelength conversion on the first blue light 11 to obtain yellow excited light 44; the reflection surface 421 of the substrate 42 or the reflection layer 43 of the wavelength conversion device 4 reflects the yellow excitation light 44, and directs the yellow excitation light 44 toward the spectroscopic combiner 5. The light splitting and combining device 5 transmits the yellow excited light 44 and reflects the second blue light 21, and the second blue light 21 reflected by the light splitting and combining device 5 and the yellow excited light 44 transmitted by the light splitting and combining device 5 are combined to output.
Specifically, the light splitting and combining device 5 has a first surface and a second surface that are oppositely disposed, in fig. 1, the first surface is a left upper surface of the light splitting and combining device 5, and the second surface is a right lower surface of the light splitting and combining device 5. The first blue light 11 is incident on the first surface of the light splitting and combining device 5, is reflected by the first surface of the light splitting and combining device 5, and is incident on the fluorescent layer 41 of the wavelength conversion device 4, and generates the yellow excited light 44, which is then incident on the light splitting and combining device 5 through the reflective surface 421 of the substrate 42 or the reflective layer 43 of the wavelength conversion device 4, and the yellow excited light 44 is transmitted through the first surface and the second surface of the light splitting and combining device 5, and the yellow excited light 44 is emitted from the second surface of the light splitting and combining device 5. The second blue light 21 is emitted to the second surface of the light splitting and combining device 5, is reflected by the second surface of the light splitting and combining device 5, and the second blue light 21 reflected by the light splitting and combining device 5 and the yellow excited light 44 transmitted by the light splitting and combining device 5 are combined to output white light.
As shown in fig. 2, the laser light source system includes a first excitation light source 1, a second excitation light source 2, a first light uniformizing element 31, a second light uniformizing element 32, a wavelength conversion device 4, and a light splitting and combining device 5.
The first excitation light source 1 is configured to emit first blue light 11, and the second light source 2 is configured to emit second blue light 21. The first excitation light source 1 is a laser light source, and the second light source 2 may be a laser light source, or other light sources such as an LED light source; the wavelength of the first blue light 11 may or may not be the same as the wavelength of the second blue light 21.
The first light uniformizing element 31 is disposed between the first excitation light source 1 and the light splitting and combining device 5, and the second light uniformizing element 32 is disposed between the second light source 2 and the light splitting and combining device 5. The first dodging element 31 is used for dodging the first blue light 11 emitted by the first excitation light source 1, and the second dodging element 32 is used for dodging the second blue light 21 emitted by the second excitation light source 2; the first blue light 11 and the second blue light 21 respectively subjected to the dodging process can obtain higher light energy utilization rate and more uniform illuminance. In the embodiment of the present invention, the first light uniformizing element 31 may adopt a light uniformizing rod or a fly eye lens, etc., and the second light uniformizing element 32 may adopt a light uniformizing rod or a fly eye lens, etc.
As shown in fig. 3, in some alternative embodiments, the wavelength conversion device 4 includes a fluorescent layer 41 and a substrate 42 having a reflective surface 421, the fluorescent layer 41 is disposed on the reflective surface 421 of the substrate 42; that is, the substrate 42 itself has a reflection function, and the wavelength conversion device 4 includes a two-layer structure of the fluorescent layer 41 and the substrate 42 having a reflection function. As shown in fig. 4, in some alternative embodiments, the wavelength conversion device 4 includes a fluorescent layer 41, a substrate 42, and a reflective layer 43, the reflective layer 43 being located between the substrate 42 and the fluorescent layer 41; that is, the substrate 42 itself has no reflection function and plays a role of supporting the reflection layer 43 and the fluorescent layer 41, and the wavelength conversion device 4 includes a three-layer structure including the fluorescent layer 41, the substrate 42 and the reflection layer 43.
As shown in fig. 2, the light splitting and combining device 5 has the characteristics of transmitting blue light and reflecting yellow light. In the embodiment of the present invention, the light splitting and combining device 5 may be a dichroic filter, which has the characteristics of reflecting light in a part of wavelength bands and transmitting light in another part of wavelength bands, and can achieve the purposes of transmitting blue light and reflecting yellow light.
As shown in fig. 2, 3 and 4, the light splitting and combining device 5 transmits the first blue light 11 to the fluorescent layer 41 of the wavelength conversion device 4, and the fluorescent layer 41 of the wavelength conversion device 4 receives the first blue light 11 and performs wavelength conversion on the first blue light 11 to obtain yellow excited light 44; the reflection surface 421 of the substrate 42 or the reflection layer 43 of the wavelength conversion device 4 reflects the yellow excitation light 44, and directs the yellow excitation light 44 toward the spectroscopic combiner 5. The light splitting and combining device 5 reflects the yellow excited light 44 and transmits the second blue light 21, and the second blue light 21 transmitted by the light splitting and combining device 5 and the yellow excited light 44 reflected by the light splitting and combining device 5 are combined to output.
Specifically, the light splitting and combining device 5 has a first surface and a second surface that are oppositely disposed, in fig. 2, the first surface is a left upper surface of the light splitting and combining device 5, and the second surface is a right lower surface of the light splitting and combining device 5. The first blue light 11 is emitted toward the second surface of the light splitting and combining device 5, transmitted through the second surface and the first surface of the light splitting and combining device 5, and then emitted toward the fluorescent layer 41 of the wavelength conversion device 4, and generates the yellow excited light 44, which is emitted toward the light splitting and combining device 5 through the reflective surface 421 of the substrate 42 or the reflective layer 43 of the wavelength conversion device 4, and the yellow excited light 44 is reflected by the first surface of the light splitting and combining device 5 and emitted. The second blue light 21 is emitted to the second surface of the light splitting and combining device 5, and after being transmitted through the second surface and the first surface of the light splitting and combining device 5, is combined with the yellow excited light 44 reflected by the light splitting and combining device 5 to output white light.
As shown in fig. 3 and 4, in some alternative embodiments, the thickness of the fluorescent layer 41 is equal to or less than 0.4mm, or equal to or less than 0.3mm, or equal to or less than 0.15 mm; in a more preferred embodiment, the thickness of the fluorescent layer 41 is 0.3mm or less. When the thickness of the fluorescent layer 41 is less than or equal to 0.3mm, not only can the fluorescent powder in the fluorescent layer 41 be sufficiently excited to emit yellow excited 44 light and be reflected to the emergent light path, but also the heat accumulation in the fluorescent layer 41 can be reduced, the excitation efficiency of the fluorescent layer 41 can be improved, and the service life of the fluorescent layer 41 can be ensured.
In some alternative embodiments, as shown in fig. 1 and fig. 2, the laser light source system further includes a first scattering element 61, the first scattering element 61 is disposed between the first excitation light source 1 and the first dodging element 31, and the first scattering element 61 is configured to scatter and dodge the first blue light 11 emitted by the first excitation light source 1. The scattered and homogenized first blue light 11 is further homogenized by the first light homogenizing element 31. The first blue light 11 after scattering and light-homogenizing treatment is not easy to generate interference phenomenon, thereby reducing speckle phenomenon of the output white light. In the embodiment of the present invention, the first diffusion element 61 may be a diffusion sheet.
In some alternative embodiments, as shown in fig. 1 and 2, the laser light source system further includes a second scattering element 62, the second scattering element 62 is disposed between the second light source 2 and the second light uniformizing element 32, and the second scattering element 62 is used for scattering and uniformizing the second blue light 21 emitted from the second light source 2. The scattered and homogenized second blue light 21 is further homogenized by a second light homogenizing element 32. The scattered and homogenized second blue light 21 is not easy to generate interference phenomenon, thereby reducing speckle phenomenon of the output white light. In an embodiment of the present invention, the second scattering element 62 may be a scattering sheet.
In some alternative embodiments, as shown in fig. 1, the laser light source system further includes a first reflecting mirror 71 and a first lens group 72, and the first reflecting mirror 71 and the first lens group 72 are sequentially disposed between the first excitation light source 1 and the light splitting and combining device 5. The first blue light 11 can change the direction of the light path through the first reflector 71, which is beneficial to saving the space occupied by the whole laser light source system; the first blue light 11 can be converged and collected by the first lens group 72, which is beneficial to reducing the size of the light splitting and combining device 5.
In some alternative embodiments, as shown in fig. 1 and fig. 2, the laser light source system further includes a second reflecting mirror 73 and a second lens group 74, and the second reflecting mirror 73 and the second lens group 74 are sequentially disposed between the second light source 2 and the light splitting and combining device 5. The light path direction of the second blue light 21 can be changed through the second reflector 73, which is beneficial to saving the space occupied by the whole laser light source system; the second blue light 21 can be converged and converged by the second lens group 74, which is beneficial to reducing the size of the light splitting and combining device 6.
In some alternative embodiments, as shown in fig. 1 and 2, the first excitation light source 1 includes a first blue laser array 12, a second blue laser array 13, and a polarization combining element 14. The planes of the first blue laser array 12 and the second blue laser array 13 are perpendicular to each other, the polarization light combination element 14 is located between the first blue laser array 12 and the second blue laser array 13, and the polarization light combination element 14 is arranged to intersect the planes of the first blue laser array 12 and the second blue laser array 13. The polarization states of the light emitted by the first blue light exciter array 12 and the light emitted by the second blue light exciter array 13 are different, and the polarization light combining element 14 combines and outputs the light emitted by the first blue light laser array 12 and the light emitted by the second blue light laser array 13 to obtain the first blue light 11.
Specifically, the first blue laser array 12 is provided with 16 blue lasers arranged in a rectangular array, and the second blue laser array 13 is provided with 16 blue lasers arranged in a rectangular array; compared with 32 blue lasers arranged in a rectangular array directly on the same plane, the first blue laser array 12 and the second blue laser array 13 arranged perpendicularly to each other can obviously utilize space more reasonably, and reduce the space occupied by the first excitation light source 1. Specifically, the first blue laser array 12 may emit P-polarized blue light 121, and the second blue laser array 13 may emit S-polarized blue light 131; the polarization light combination element 14 can transmit the P-polarized blue light 121 and reflect the S-polarized blue light 131, and the P-polarized blue light 121 and the S-polarized blue light 131 are subjected to polarization light combination by the polarization light combination element 14 to output first blue light 11; the polarization combining element 14 combines the light emitted from the first blue laser array 12 and the light emitted from the second blue laser array 13, thereby obtaining the first blue light 11 with high luminance.
In some alternative embodiments, as shown in fig. 1 and fig. 2, the laser light source system further includes a third lens group 75, and the third lens group 75 is disposed between the light splitting and combining device 5 and the wavelength conversion device 4. The first blue light 11 reflected by the light splitting and combining device 5 can be converged by the third lens group 75, which is beneficial to reducing the size of the wavelength conversion device 4 or reducing the material of the fluorescent layer 41 of the wavelength conversion device 4.
In some alternative embodiments, as shown in fig. 1, fig. 2 and fig. 4, the wavelength conversion device 4 is disposed in a closed housing 8, the housing 8 is opened with a light-passing port 81, and the third lens group 75 is disposed at the light-passing port 81 of the housing 8. By arranging the wavelength conversion device 4 in a closed housing, the dustproof effect of the wavelength conversion device 4 can be improved, which is beneficial to prolonging the service life of the wavelength conversion device 4; but also the interference and influence of the external light on the wavelength conversion device 4 can be reduced to obtain highly pure yellow excited light 44.
In some alternative embodiments, as shown in fig. 1 and 2, the wavelength conversion device 4 is disposed in the optical path of the first blue light 11 and is movable relative to each other, which is beneficial to improve the heat dissipation effect of the wavelength conversion device 4 and further improve the service life of the wavelength conversion device 4. Specifically, the relative movement of the wavelength conversion device 4 and the first blue light 11 with respect to each other may be a circular rotation, a reciprocating linear motion, or the like.
In some alternative embodiments, the lighting periods of the first
excitation light source 1 and the second
excitation light source 2 overlap in the same period. For example, as shown in FIG. 5, in the same period t
1In the first
excitation light source 1, the first excitation light source is in the range of 0 to
Is extinguished within a time period of
To
Is lit during a time period of
To t
1Is extinguished within a time period of (1); in the range of 0 to 2 of the second light source
Is extinguished within a time period of
To t
1Is lit up within a time period of (a); then, the first
excitation light source 1 and the second
excitation light source 2 are at
To
I.e. the first and second
excitation light sources 1, 2 are on during the on-period
To
Overlapping; at this time, the laser light source system is in the range of 0 to
Is extinguished within a time period of
To
During a period of time of outputting blue light
To
During a period of time of outputting white light
To t
1Yellow light is output during the period of time. By setting the first
excitation light source 1 and the second
excitation light source 2 to overlap in the lighting time periods in the same period, multicolor light can be emitted simultaneously in the same period, and the light output amount per unit time is improved.
In some alternative embodiments, the first excitation light source is illuminated for a full period, and the second excitation light source is illuminated for a portion of the period or for the full period during the same period. For example, as shown in FIG. 6, in the same period t
2In the first
excitation light source 1, the first excitation light source is in the range of 0 to t
2Is lit up within a time period of (a); second
light source 2 is in the range of 0 to
Is extinguished within a time period of
To t
1Is lit up within a time period of (a); at this time, the laser light source system is in the range of 0 to
During a period of time of (2) yellow light is output
To t
1White light is output during the time period. By setting the first
excitation light source 1 to light the whole period in the same period and the second
excitation light source 2 to light the partial period in the same period, multicolor light can be emitted simultaneously in the same period, and the light output amount per unit time can be improved. For another example, as shown in FIG. 7, in the same period t
3In the first
excitation light source 1, the first excitation light source is in the range of 0 to t
3Is lit up within a time period of (a); second
light source 2 is in the range of 0 to t
3Is lit up within a time period of (a); at this time, the laser light source system is in the range of 0 to t
3White light is output during the time period. By providing the first
excitation light source 1 and the second excitation light sourceThe two
light sources 2 respectively light the whole period in the same period, and white light which is continuously output can be obtained in the same period. The embodiment of the invention also provides laser projection equipment, which comprises an optical machine, a lens and the laser light source system. The laser light source system is used for providing light source beams for the optical machine, the optical machine is used for modulating the light source beams and outputting the light source beams to the lens, and the lens is used for imaging and projecting the light source beams to a projection medium to form a projection picture.
In summary, in the laser light source system and the laser projection apparatus provided in the embodiment of the invention, the first blue light 11 emitted by the first excitation light source 1 passes through the wavelength conversion device 5 to generate the yellow excited light 51, and the yellow excited light 51 and the second blue light 21 emitted by the second light source 2 combine to form a white light output. Compared with the scheme of using laser light sources with three colors of red, green and blue to mix colors to obtain white light output, the embodiment of the invention can obtain the white light output only by adopting two groups of blue excitation light sources, and the blue excitation light sources have the advantages of simple integral structure, lower cost and high light emitting efficiency because the blue excitation light sources have lower cost and higher electro-optic conversion efficiency compared with the red and green excitation light sources.
The above embodiments are only for illustrating the technical solutions of the present invention, and not for limiting the same; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may be modified or some technical features may be equivalently replaced; such modifications and substitutions do not substantially depart from the spirit and scope of the embodiments of the present invention, and are intended to be included within the scope of the present invention.