A light emitting device

Abstract

The light-emitting device provided by the present invention includes a first light source, a second light source, a dichroic mirror, a wavelength conversion device, a first optical path adjustment device or a second optical path adjustment device, and a first scattering optical system. In the present invention, the light mixing effect of the emitted light can be improved by using the first scattering optical system. The color temperature of the emitted light of the light-emitting device can be freely adjusted by adjusting the power of the first light source and the second light source separately. A laser that can emit light of different main wavelengths can also be used in the second light source to improve the color rendering index of the emitted light of the light-emitting device. The light emitted by the first light source in the present invention is all used to excite the wavelength conversion device. Compared with the prior art solution, the light-emitting device provided in the present invention can achieve a higher luminous flux output without increasing the optical extension. If a polarization selection element is used in the first light source, the luminous flux output of the light-emitting device can be further improved.

Description

Technical Field

[0001] The present invention relates to the field of lighting, particularly solid-state lighting. The light-emitting device provided by the present invention is suitable for use in systems requiring high light intensity and low etendue, such as entertainment lighting systems, projection systems, automotive lighting systems, medical lighting systems, searchlight systems, field lighting systems, marine lighting systems, and portable lighting systems. Background Art

[0002] As an ideal point light source, laser has the advantages of small optical etendue, long life and no mercury. Using it as a light source to excite fluorescent materials can produce colored light or white light. At the same time, when used in conjunction with optical elements, an ideal light-emitting device with a small optical etendue can be obtained.

[0003] Figure 1 Schematic diagram of the structure of an existing light emitting device using a dichroic mirror. Figure 1 As shown, a conventional light-emitting device using a dichroic mirror includes a light source 101, a light source 102, a dichroic mirror 103, a lens assembly 104 (including a lens 104a and a lens 104b), a wavelength conversion device 105 (including a reflective layer 105a and a wavelength conversion layer 105b), a transmissive diffuser 106, a collimating lens 107, and a focusing lens 108. The light source 101 includes a plurality of lasers 101a and a plurality of collimating lenses 101b corresponding to the lasers 101a. The lasers 101a emit blue light. The light source 102 includes a plurality of lasers 102a and a plurality of collimating lenses 102b corresponding to the lasers 102a. The lasers 102a also emit blue light.

[0004] Dichroic mirror 103 transmits blue light and reflects yellow light. Blue light emitted by light source 101 passes through dichroic mirror 103 and then travels to lens assembly 104. Lens assembly 104 focuses the blue light from dichroic mirror 103 toward wavelength conversion device 105. Wavelength conversion device 105 is reflective and includes a reflective layer 105a and a wavelength conversion layer 105b (e.g., a yellow phosphor layer) disposed on reflective layer 105a. Wavelength conversion device 105 converts the incident blue light into yellow light and directs it toward lens assembly 104. The yellow light is collected by lens assembly 104 and then travels toward dichroic mirror 103, which reflects the yellow light. Blue light emitted by light source 102 travels toward transmissive diffuser 106, which homogenizes the light before directing it toward collimating lens 107. The collimated blue light from collimating lens 107 travels toward dichroic mirror 103, which transmits it. The yellow light reflected by the dichroic mirror 103 and the blue light transmitted through the dichroic mirror 103 are combined into a mixed light, and the mixed light of the yellow light and the blue light is white light. Finally, the focusing lens 108 converges the white light and emits it from the light emitting device.

[0005] Figure 1 The shortcomings of the shown solution are that the transmissive diffuser 106 cannot well evenly distribute the blue light emitted by the light source 102, and the light distribution of the blue light evenly distributed by the transmissive diffuser 106 and the light distribution of the yellow light emitted by the wavelength conversion device 105 are difficult to completely match, which will result in poor mixing of the blue light and the yellow light in the output light of the light-emitting device.

[0006] Figure 2 This is a schematic diagram of the structure of an existing light emitting device using a polarization beam splitter. Figure 2 As shown, the conventional light-emitting device includes a light source 201, a quarter-wave plate 202, a polarization beam splitter 203, a lens group 204 (including lens 204a and lens 204b), a wavelength conversion device 205 (including a reflective layer 205a and a wavelength conversion layer 205b), a quarter-wave plate 206, a lens group 207 (including lens 207a and lens 207b), a reflective scattering plate 208, and a focusing lens 209. The light source 201 includes a plurality of lasers 201a and a plurality of collimating lenses 201b corresponding to the lasers 201a. The lasers 201a emit S-polarized blue light.

[0007] Polarization beam splitter 203 reflects S-polarized blue light and transmits P-polarized blue light, while also transmitting yellow light. S-polarized blue light emitted by light source 201 passes through quarter-wave plate 202 and is converted into blue light composed of a mixture of S-polarized and P-polarized components in a specified ratio. The light then enters polarization beam splitter 203, where it is separated into S-polarized blue light and P-polarized blue light. Polarization beam splitter 203 reflects the S-polarized blue light and transmits the P-polarized blue light. The S-polarized blue light reflected by polarization beam splitter 203 is directed toward lens assembly 204, while the P-polarized blue light that has passed through polarization beam splitter 203 is directed toward quarter-wave plate 206. Lens group 204 converges the S-polarized blue light toward wavelength conversion device 205. Wavelength conversion device 205 is reflective and includes a reflective layer 205a and a wavelength conversion layer 205b (e.g., a yellow phosphor layer) disposed on reflective layer 205a. Wavelength conversion device 205 converts the S-polarized blue light into yellow light and directs it toward lens group 204. The yellow light is collected by lens group 204 and directed toward polarization beam splitter 203, which transmits the yellow light. After passing through quarter-wave plate 206, the P-polarized blue light is converted into circularly polarized blue light. Lens assembly 207 converges the circularly polarized blue light toward reflective diffuser 208. The circularly polarized blue light is reflected by reflective diffuser 208 and then directed toward lens assembly 207. It is then collected by lens assembly 207 and directed toward quarter-wave plate 206. After passing through quarter-wave plate 206, the circularly polarized blue light is converted into S-polarized blue light. This S-polarized blue light is directed toward polarization beam splitter 203, which reflects the S-polarized blue light. The yellow light that has passed through polarization beam splitter 203 and the S-polarized blue light reflected by polarization beam splitter 203 combine to form a mixed light beam. This mixed light beam of yellow and blue light is white light. Finally, focusing lens 209 converges this white light beam, which is then emitted from the light-emitting device.

[0008] Figure 2 The solution shown has the following shortcomings:

[0009] First, in Figure 2In the illustrated scheme, the S-polarized blue light emitted by light source 201 passes through quarter-wave plate 202 and is converted into blue light composed of a mixture of S-polarized and P-polarized components in a specified ratio. This ratio of S-polarized to P-polarized components determines the ratio of blue to yellow light in the light output from the light-emitting device, and thus the color temperature of the light output from the entire light-emitting device. However, this structure does not achieve adjustable color temperature of the output light. Based on this structure, the ratio of S-polarized to P-polarized light components can be changed by rotating quarter-wave plate 202, thereby achieving adjustable color temperature of the light output from the light-emitting device. However, since the adjustment of blue and yellow light is not independent of each other, increasing or decreasing the ratio of blue light directly affects the output of yellow light. Therefore, the process of adjusting the color temperature will affect the output of the light-emitting device.

[0010] Second, in Figure 2 In the illustrated embodiment, a portion of the blue light emitted by light source 201 is converted into yellow light by wavelength conversion device 205. The remaining blue and yellow light mix to form white light. Wavelength conversion device 205 comprises a reflective layer 205a and a wavelength conversion layer 205b (e.g., a yellow phosphor layer) disposed on reflective layer 205a. The yellow phosphor emits yellow light when excited by blue light. To achieve efficient light output, a laser is typically selected that emits light in the wavelength band that most easily excites the yellow phosphor, thereby maximizing the amount of yellow light. For example, a blue laser with a dominant wavelength of 455nm is selected. However, the spectrum of the blue light in the synthesized white light is very narrow because the primary component of the blue light is monochromatic light at 455nm. Consequently, the color rendering index of the light emitted by the light-emitting device is generally low.

[0011] Third, in Figure 2 In the solution shown, if the luminous flux output of the light-emitting device is to be significantly improved, the number of lasers 201a in the light source 201 needs to be increased. However, this will increase the optical expansion of the entire light-emitting device, which will not meet the needs of some application fields that require a small optical expansion, such as entertainment lighting systems, projection systems, etc. Summary of the Invention

[0012] The technical problems to be solved by the present invention are: first) the existing light-emitting device using a dichroic mirror has a poor mixing effect on the output light; second) the existing light-emitting device using a polarization beam splitter will affect the output of the luminous flux during the process of adjusting the color temperature; third) the color rendering index of the output light of the existing light-emitting device using a polarization beam splitter is low; fourth) if the output of the luminous flux of the light-emitting device needs to be significantly improved, the optical extension of the existing light-emitting device using a polarization beam splitter will be increased.

[0013] In order to solve the above technical problems, a technical solution of the present invention is to provide a light-emitting device, characterized in that it includes a first light source, a second light source, a dichroic mirror, a wavelength conversion device, a first light path adjustment device and a first scattering optical system, wherein:

[0014] The first light source is used to emit light in a first wavelength band;

[0015] The second light source is used to emit light in a second wavelength band, and the second wavelength band is the same as or different from the first wavelength band;

[0016] The dichroic mirror receives the light of the first wavelength band emitted by the first light source and transmits or reflects the light;

[0017] When the dichroic mirror transmits the light of the first wavelength band emitted by the first light source, the wavelength conversion device receives the light of the first wavelength band transmitted through the dichroic mirror and converts it into light of a third wavelength band that is different from both the first wavelength band and the second wavelength band; the dichroic mirror reflects the light of the third wavelength band from the wavelength conversion device; and the light of the third wavelength band reflected by the dichroic mirror is emitted toward the first optical path adjustment device;

[0018] When the dichroic mirror reflects the light of the first wavelength band emitted by the first light source, the wavelength conversion device receives the light of the first wavelength band reflected from the dichroic mirror and converts it into light of a third wavelength band that is different from both the first wavelength band and the second wavelength band; the dichroic mirror transmits the light of the third wavelength band from the wavelength conversion device; the light of the third wavelength band that has passed through the dichroic mirror is emitted toward the first optical path adjustment device;

[0019] The first optical path adjustment device receives the light of the second wavelength band emitted by the second light source and causes the light to be at least partially transmitted or at least partially reflected;

[0020] When the first optical path adjusting device causes at least a portion of the light of the second wavelength band emitted by the second light source to be transmitted, the first scattering optical system receives the light of the second wavelength band transmitted through the first optical path adjusting device, reflects the light and forms scattered light of the second wavelength band; the first optical path adjusting device reflects at least a portion of the light of the second wavelength band from the first scattering optical system; and the first optical path adjusting device causes the light of the third wavelength band from the dichroic mirror to be transmitted.

[0021] When the first optical path adjusting device causes at least part of the light of the second wavelength band emitted by the second light source to be reflected, the first scattering optical system receives the light of the second wavelength band reflected from the first optical path adjusting device, reflects it and forms scattered light of the second wavelength band; the first optical path adjusting device causes at least part of the light of the second wavelength band from the first scattering optical system to be transmitted; the first optical path adjusting device reflects the light of the third wavelength band from the dichroic mirror.

[0022] In the above technical solution, the wavelength conversion device is reflective and can be static or dynamic:

[0023] The static wavelength conversion device includes a reflective layer and a wavelength conversion layer arranged on the reflective layer, wherein the wavelength conversion layer absorbs incident light of a first wavelength band and emits light of a third wavelength band after being excited.

[0024] The dynamic wavelength conversion device is a rotatable fluorescent wheel, which includes a reflective layer and a wavelength conversion layer arranged on the reflective layer, wherein the wavelength conversion layer absorbs incident light of a first wavelength band and emits light of a third wavelength band after being excited.

[0025] It should be noted that if two or more different wavelength conversion layers are provided on the reflective layers of different sectors of the fluorescent wheel, each wavelength conversion layer absorbs the incident light of the first wavelength band and emits converted light of different wavelength bands after being excited. At this time, the combined light of these converted light of different wavelength bands should be regarded as light of the third wavelength band.

[0026] In the above technical solution, the dichroic mirror can reflect light of a first wavelength band having a certain polarization direction and transmit light of a first wavelength band having another polarization direction. In this case, the polarization state and / or polarization direction of the light of the first wavelength band emitted by the first light source and directed toward the dichroic mirror will affect the role played by the dichroic mirror in the optical path (for example, whether it reflects the light of the first wavelength band or transmits the light of the first wavelength band). The dichroic mirror can also reflect or transmit light of the first wavelength band having any polarization state and / or any polarization direction. In this case, the polarization state and / or polarization direction of the light of the first wavelength band emitted by the first light source and directed toward the dichroic mirror will not affect the role played by the dichroic mirror in the optical path (for example, whether it reflects the light of the first wavelength band or transmits the light of the first wavelength band).

[0027] The dichroic mirror can be a flat dichroic mirror or a cubic dichroic mirror.

[0028] Preferably, the first optical path adjustment device is a first polarization beam splitter, and the first polarization beam splitter has the following first characteristic with respect to the incident light of the second wavelength band: reflecting the linearly polarized light of the second wavelength band having a first polarization direction and transmitting the linear polarized light of the second wavelength band having a second polarization direction, wherein the first polarization direction is different from the second polarization direction; the first polarization beam splitter has the following second characteristic with respect to the incident light of the third wavelength band: transmitting or reflecting the light of the third wavelength band.

[0029] In the above technical solution, the first polarization beam splitter is a flat-plate polarization beam splitter or a cubic polarization beam splitter.

[0030] Preferably, it also includes a polarization conversion element, which is located on the optical path between the first optical path adjustment device and the first scattering optical system, and is used to change the polarization direction or polarization state of the light of the second wavelength band emitted from the first optical path adjustment device to the first scattering optical system when it is reflected by the first scattering optical system and returns to the first optical path adjustment device.

[0031] Preferably, the polarization conversion element is a first quarter wave plate.

[0032] Preferably, the first light source includes N first lasers and N first collimating elements corresponding one-to-one to the N first lasers, where N≥1, wherein:

[0033] The first laser is used to emit light in the first wavelength band;

[0034] The first collimating element is integrated into the first laser or arranged outside the first laser, and is used to collimate the light of the first wavelength band emitted by the first laser.

[0035] In the above technical solution, the first collimating element can be integrated inside the first laser. When the first collimating element is not integrated inside the first laser, a first collimating element (for example, a collimating lens) can also be added outside the first laser to collimate the light emitted by the first laser.

[0036] In addition to the first laser and the first collimating element mentioned in the above technical solution, the first light source may also include other optical elements (such as reflectors). These optical elements can be used to collect the light emitted from the first laser and ultimately form the first band of light emitted by the first light source.

[0037] Preferably, the first light source further includes a polarization selection element, the characteristic of the polarization selection element is to reflect the S-polarized light of the first band and transmit the P-polarized light of the first band, at least one of the first lasers in the first light source is used to emit the S-polarized light of the first band to form incident light one, and the remaining first lasers in the first light source are used to emit the P-polarized light of the first band to form incident light two, and the polarization selection element combines the incident light one and the incident light two into one light and then emits it.

[0038] Preferably, the second light source includes M second lasers and M second collimating elements corresponding one-to-one to the M second lasers, M≥1, wherein:

[0039] The second laser is used to emit light in the second wavelength band;

[0040] The second collimating element is integrated into the second laser or arranged outside the second laser, and is used to collimate the light of the second wavelength band emitted by the second laser.

[0041] In the above technical solution, the second collimating element can be integrated inside the second laser. When the second collimating element is not integrated inside the second laser, a second collimating element (for example, a collimating lens) can also be added outside the second laser to collimate the light emitted by the second laser.

[0042] In addition to the second laser and the second collimating element mentioned in the above technical solution, the second light source may also contain other optical elements (such as reflectors). These optical elements can be used to collect the light emitted from the second laser and ultimately form the second band of light emitted by the second light source.

[0043] Preferably, the first scattering optical system is composed of a first reflective scattering plate, or a first transmissive scattering plate and a first reflecting mirror.

[0044] In the above technical solution, the first reflective scattering plate may be a static or dynamic rotatable first reflective scattering plate.

[0045] Preferably, it also includes a first collecting optical system, which is located on the optical path between the dichroic mirror and the wavelength conversion device, and is used to converge the light of the first band from the dichroic mirror toward the wavelength conversion device, and at the same time to collect the light of the third band from the wavelength conversion device and direct it toward the dichroic mirror.

[0046] In the above technical solution, the first collecting optical system can be composed of a lens, a lens group, a compound parabolic concentrator or a conical light guide column alone, or can be composed of any combination of the above-mentioned optical elements.

[0047] Preferably, it also includes a second collecting optical system, which is located on the optical path between the first optical path adjusting device and the first scattering optical system, and is used to converge the light of the second wavelength band from the first optical path adjusting device toward the first scattering optical system, and at the same time to collect the light of the second wavelength band from the first scattering optical system and direct it toward the first optical path adjusting device.

[0048] In the above technical solution, the second collecting optical system can be composed of a lens, a lens group, a compound parabolic concentrator or a conical light guide column alone, or can be composed of any combination of the above-mentioned optical elements.

[0049] Preferably, a first light homogenizing optical system is further included, and the first light homogenizing optical system is located on the optical path from the first light source to the dichroic mirror, and is used for homogenizing the light of the first wavelength band emitted by the first light source.

[0050] In the above technical solution, the first light homogenization optical system can be composed of a diffuser, an optical integrator rod, or at least one fly-eye lens array, wherein the optical integrator rod can be solid or hollow. Furthermore, because the use of a diffuser causes some diffusion of the light in the first wavelength band emitted by the first light source, a positive lens can be disposed in the optical path from the first light source to the diffuser, or from the diffuser to the dichroic mirror, to converge the light in the first wavelength band emitted from the first light source to the dichroic mirror.

[0051] Preferably, it further comprises a second light uniforming optical system, which is located on the optical path from the second light source to the first light path adjustment device and is used for uniformly uniformizing the light of the second wavelength band emitted by the second light source.

[0052] In the above technical solution, the second light homogenization optical system can be composed of a diffuser, an optical integrator rod, or at least one fly-eye lens array, wherein the optical integrator rod can be solid or hollow. Furthermore, because the use of a diffuser causes some diffusion of the light in the second wavelength band emitted by the second light source, a positive lens can be disposed in the optical path from the second light source to the diffuser, or in the optical path from the diffuser to the first optical path adjustment device, to converge the light in the second wavelength band emitted from the second light source to the first optical path adjustment device.

[0053] Preferably, it further comprises a focusing optical system for converging the light emitted from the first optical path adjusting device.

[0054] In the above technical solution, the focusing optical system can be composed of one or more lenses.

[0055] Preferably, the optical system further comprises a first lens group, which is located on the optical path from the first light source to the dichroic mirror and is used to reduce the light beam formed by the light of the first wavelength band emitted by the first light source.

[0056] Preferably, it further comprises a second lens group, which is located on the optical path from the second light source to the first optical path adjustment device and is used to reduce the light beam formed by the light of the second wavelength band emitted by the second light source.

[0057] Preferably, it also includes a reflective element, which is located on the optical path between the second light source and the first optical path adjustment device. The reflective element has a transmission area and a reflection area. The transmission area allows the light of the second wavelength band to pass through or transmit through, and the reflection area is used to reflect the light of the second wavelength band from the first optical path adjustment device and make at least part of the light therein return to the first optical path adjustment device.

[0058] In the above technical solution, the reflective element can be planar or non-planar. The transmissive region of the reflective element can be a light-through hole or a transmissive structure composed of a light-transmitting material. The reflective element can also be a transmissive diffuser plate partially coated with a reflective film, wherein the area of ​​the transmissive diffuser plate not coated with the reflective film is the transmissive region, and the area of ​​the transmissive diffuser plate coated with the reflective film is the reflective region.

[0059] Preferably, it also includes a light-guiding optical system, which is located on the optical path from the second light source to the first optical path adjustment device, and is used to guide at least part of the light of the second wavelength band emitted by the second light source to pass through or transmit through the transmission area of ​​the reflective element and then be incident on the first optical path adjustment device.

[0060] In the above technical solution, the light-guiding optical system can be composed solely of a lens, a compound parabolic concentrator, or a light-guiding column, or any combination of the aforementioned optical elements. The number of lenses, compound parabolic concentrators, and light-guiding columns is determined as needed and can be one, two, or more. The light-guiding column can be solid or hollow, and its end face can be planar or non-planar.

[0061] Preferably, it also includes a second scattering optical system, the first optical path adjusting device allows the light of the second wavelength band emitted by the second light source to be partially transmitted and partially reflected and then emitted from a different optical path, the first scattering optical system receives the light of the second wavelength band emitted from one of the optical paths, the dichroic mirror receives the light of the second wavelength band emitted from the other optical path, allows it to be transmitted or reflected and then emitted to the second scattering optical system, the second scattering optical system reflects it and forms scattered light of the second wavelength band; the dichroic mirror allows the light of the second wavelength band from the second scattering optical system to be reflected or transmitted and then emitted to the first optical path adjusting device, and the first optical path adjusting device allows it to be transmitted or reflected.

[0062] Preferably, the second scattering optical system is composed of a second reflective scattering plate, or a second transmissive scattering plate and a second reflecting mirror.

[0063] In the above technical solution, the second reflective scattering plate may be a static or dynamic rotatable second reflective scattering plate.

[0064] Preferably, a third collecting optical system is further included, which is located on the optical path between the dichroic mirror and the second scattering optical system, and is used to converge the light of the second wavelength band from the dichroic mirror toward the second scattering optical system, and at the same time to collect the light of the second wavelength band from the second scattering optical system and direct it toward the dichroic mirror.

[0065] In the above technical solution, the third collecting optical system can be composed of a lens, a lens group, a compound parabolic concentrator or a conical light guide column alone, or can be composed of any combination of the above-mentioned optical elements.

[0066] Preferably, the optical system further comprises a second quarter-wave plate, wherein the second quarter-wave plate is located on the optical path between the dichroic mirror and the second scattering optical system.

[0067] Another technical solution of the present invention is to provide a light-emitting device, characterized in that it includes a first light source, a second light source, a dichroic mirror, a wavelength conversion device, a second light path adjustment device, and a first scattering optical system, wherein:

[0068] The first light source is used to emit light in a first wavelength band;

[0069] The second light source is used to emit light in a second wavelength band, and the second wavelength band is the same as or different from the first wavelength band;

[0070] The second optical path adjusting device receives the light of the second wavelength band emitted by the second light source and causes the light to be at least partially transmitted or at least partially reflected;

[0071] When the second optical path adjusting device causes at least a portion of the light of the second wavelength band emitted by the second light source to be transmitted, the first scattering optical system receives the light of the second wavelength band transmitted through the second optical path adjusting device, reflects the light and forms scattered light of the second wavelength band; the second optical path adjusting device reflects at least a portion of the light of the second wavelength band from the first scattering optical system, and the light of the second wavelength band from the first scattering optical system reflected by the second optical path adjusting device is emitted toward the dichroic mirror;

[0072] When the second optical path adjusting device causes the light of the second wavelength band emitted by the second light source to be at least partially reflected, the first scattering optical system receives the light of the second wavelength band reflected from the second optical path adjusting device, reflects it and forms scattered light of the second wavelength band; the second optical path adjusting device causes at least a portion of the light of the second wavelength band from the first scattering optical system to be transmitted; the light of the second wavelength band from the first scattering optical system that has transmitted through the second optical path adjusting device is emitted toward the dichroic mirror;

[0073] The dichroic mirror receives the light of the first wavelength band emitted by the first light source and transmits or reflects the light;

[0074] When the dichroic mirror transmits the light of the first wavelength band emitted by the first light source, the wavelength conversion device receives the light of the first wavelength band transmitted through the dichroic mirror and converts it into light of a third wavelength band that is different from both the first wavelength band and the second wavelength band; the dichroic mirror reflects the light of the third wavelength band from the wavelength conversion device; and the dichroic mirror transmits the light of the second wavelength band from the second optical path adjustment device;

[0075] When the dichroic mirror reflects the light of the first wavelength band emitted by the first light source, the wavelength conversion device receives the light of the first wavelength band reflected from the dichroic mirror and converts it into light of a third wavelength band that is different from both the first wavelength band and the second wavelength band; the dichroic mirror transmits the light of the third wavelength band from the wavelength conversion device; and the dichroic mirror reflects the light of the second wavelength band from the second optical path adjustment device.

[0076] In the above technical solution, the wavelength conversion device is reflective and can be static or dynamic:

[0077] The static wavelength conversion device includes a reflective layer and a wavelength conversion layer arranged on the reflective layer, wherein the wavelength conversion layer absorbs incident light of a first wavelength band and emits light of a third wavelength band after being excited.

[0078] The dynamic wavelength conversion device is a rotatable fluorescent wheel, which includes a reflective layer and a wavelength conversion layer arranged on the reflective layer, wherein the wavelength conversion layer absorbs incident light of a first wavelength band and emits light of a third wavelength band after being excited.

[0079] It should be noted that if two or more different wavelength conversion layers are provided on the reflective layers of different sectors of the fluorescent wheel, each wavelength conversion layer absorbs the incident light of the first wavelength band and emits converted light of different wavelength bands after being excited. At this time, the combined light of these converted light of different wavelength bands should be regarded as light of the third wavelength band.

[0080] In the above technical solution, the dichroic mirror can reflect light of a first wavelength band having a certain polarization direction and transmit light of a first wavelength band having another polarization direction. In this case, the polarization state and / or polarization direction of the light of the first wavelength band emitted by the first light source and directed toward the dichroic mirror will affect the role played by the dichroic mirror in the optical path (for example, whether it reflects the light of the first wavelength band or transmits the light of the first wavelength band). The dichroic mirror can also reflect or transmit light of the first wavelength band having any polarization state and / or any polarization direction. In this case, the polarization state and / or polarization direction of the light of the first wavelength band emitted by the first light source and directed toward the dichroic mirror will not affect the role played by the dichroic mirror in the optical path (for example, whether it reflects the light of the first wavelength band or transmits the light of the first wavelength band).

[0081] The dichroic mirror can be a flat dichroic mirror or a cubic dichroic mirror.

[0082] Preferably, the second optical path adjustment device is a second polarization splitter, and the second polarization splitter has the following characteristics with respect to the incident light of the second band: reflecting the linearly polarized light of the second band with a first polarization direction and transmitting the linear polarized light of the second band with a second polarization direction, wherein the first polarization direction is different from the second polarization direction.

[0083] In the above technical solution, the second polarization beam splitter is a flat-plate polarization beam splitter or a cubic polarization beam splitter.

[0084] Preferably, it also includes a polarization conversion element, which is located on the optical path between the second optical path adjusting device and the first scattering optical system, and is used to change the polarization direction or polarization state of the light of the second wavelength band emitted from the second optical path adjusting device to the first scattering optical system when it is reflected by the first scattering optical system and returns to the second optical path adjusting device.

[0085] Preferably, the polarization conversion element is a first quarter wave plate.

[0086] Preferably, the first light source includes N first lasers and N first collimating elements corresponding one-to-one to the N first lasers, where N≥1, wherein:

[0087] The first laser is used to emit light in the first wavelength band;

[0088] The first collimating element is integrated into the first laser or arranged outside the first laser, and is used to collimate the light of the first wavelength band emitted by the first laser.

[0089] In the above technical solution, the first collimating element can be integrated inside the first laser. When the first collimating element is not integrated inside the first laser, a first collimating element (for example, a collimating lens) can also be added outside the first laser to collimate the light emitted by the first laser.

[0090] In addition to the first laser and the first collimating element mentioned in the above technical solution, the first light source may also include other optical elements (such as reflectors). These optical elements can be used to collect the light emitted from the first laser and ultimately form the first band of light emitted by the first light source.

[0091] Preferably, the first light source further includes a polarization selection element, the characteristic of the polarization selection element is to reflect the S-polarized light of the first band and transmit the P-polarized light of the first band, at least one of the first lasers in the first light source is used to emit the S-polarized light of the first band to form incident light one, and the remaining first lasers in the first light source are used to emit the P-polarized light of the first band to form incident light two, and the polarization selection element combines the incident light one and the incident light two into one light and then emits it.

[0092] Preferably, the second light source includes M second lasers and M second collimating elements corresponding one-to-one to the M second lasers, M≥1, wherein:

[0093] The second laser is used to emit light in the second wavelength band;

[0094] The second collimating element is integrated into the second laser or arranged outside the second laser, and is used to collimate the light of the second wavelength band emitted by the second laser.

[0095] In the above technical solution, the second collimating element can be integrated inside the second laser. When the second collimating element is not integrated inside the second laser, a second collimating element (for example, a collimating lens) can also be added outside the second laser to collimate the light emitted by the second laser.

[0096] In addition to the second laser and the second collimating element mentioned in the above technical solution, the second light source may also contain other optical elements (such as reflectors). These optical elements can be used to collect the light emitted from the second laser and ultimately form the second band of light emitted by the second light source.

[0097] Preferably, the first scattering optical system is composed of a first reflective scattering plate, or a first transmissive scattering plate and a first reflecting mirror.

[0098] In the above technical solution, the first reflective scattering plate may be a static or dynamic rotatable first reflective scattering plate.

[0099] Preferably, it also includes a first collecting optical system, which is located on the optical path between the dichroic mirror and the wavelength conversion device, and is used to converge the light of the first band from the dichroic mirror toward the wavelength conversion device, and at the same time to collect the light of the third band from the wavelength conversion device and direct it toward the dichroic mirror.

[0100] In the above technical solution, the first collecting optical system can be composed of a lens, a lens group, a compound parabolic concentrator or a conical light guide column alone, or can be composed of any combination of the above-mentioned optical elements.

[0101] Preferably, it also includes a second collecting optical system, which is located on the optical path between the second optical path adjusting device and the first scattering optical system, and is used to converge the light of the second wavelength band from the second optical path adjusting device toward the first scattering optical system, and at the same time to collect the light of the second wavelength band from the first scattering optical system and direct it toward the second optical path adjusting device.

[0102] In the above technical solution, the second collecting optical system can be composed of a lens, a lens group, a compound parabolic concentrator or a conical light guide column alone, or can be composed of any combination of the above-mentioned optical elements.

[0103] Preferably, a first light homogenizing optical system is further included, and the first light homogenizing optical system is located on the optical path from the first light source to the dichroic mirror, and is used for homogenizing the light of the first wavelength band emitted by the first light source.

[0104] In the above technical solution, the first light homogenization optical system can be composed of a diffuser, an optical integrator rod, or at least one fly-eye lens array, wherein the optical integrator rod can be solid or hollow. Furthermore, because the use of a diffuser causes some diffusion of the light in the first wavelength band emitted by the first light source, a positive lens can be disposed in the optical path from the first light source to the diffuser, or from the diffuser to the dichroic mirror, to converge the light in the first wavelength band emitted from the first light source to the dichroic mirror.

[0105] Preferably, it further comprises a second light uniforming optical system, which is located on the optical path from the second light source to the second light path adjustment device and is used for uniformly uniformizing the light of the second wavelength band emitted by the second light source.

[0106] In the above technical solution, the second light homogenization optical system can be composed of a diffuser, an optical integrator rod, or at least one fly-eye lens array, wherein the optical integrator rod can be solid or hollow. Furthermore, because the use of a diffuser causes some diffusion of the light in the second wavelength band emitted by the second light source, a positive lens can be disposed in the optical path from the second light source to the diffuser, or from the diffuser to the second optical path adjustment device, to converge the light in the second wavelength band emitted from the second light source to the second optical path adjustment device.

[0107] Preferably, the optical system further comprises a focusing optical system for converging the light emitted from the dichroic mirror.

[0108] In the above technical solution, the focusing optical system can be composed of one or more lenses.

[0109] Preferably, the optical system further comprises a first lens group, which is located on the optical path from the first light source to the dichroic mirror and is used to reduce the light beam formed by the light of the first wavelength band emitted by the first light source.

[0110] Preferably, it further comprises a second lens group, which is located on the optical path from the second light source to the second optical path adjustment device and is used to reduce the light beam formed by the light of the second wavelength band emitted by the second light source.

[0111] Preferably, it also includes a reflective element, which is located on the optical path between the second light source and the second optical path adjustment device. The reflective element has a transmission area and a reflection area. The transmission area allows light of the second wavelength band to pass through or transmit through, and the reflection area is used to reflect the light of the second wavelength band from the second optical path adjustment device and make at least part of the light therein return to the second optical path adjustment device.

[0112] In the above technical solution, the reflective element can be planar or non-planar. The transmissive region of the reflective element can be a light-through hole or a transmissive structure composed of a light-transmitting material. The reflective element can also be a transmissive diffuser plate partially coated with a reflective film, wherein the area of ​​the transmissive diffuser plate not coated with the reflective film is the transmissive region, and the area of ​​the transmissive diffuser plate coated with the reflective film is the reflective region.

[0113] Preferably, it also includes a light-guiding optical system, which is located on the optical path from the second light source to the second optical path adjustment device, and is used to guide at least part of the light of the second wavelength band emitted by the second light source to pass through or transmit through the transmission area of ​​the reflective element and then be incident on the second optical path adjustment device.

[0114] In the above technical solution, the light-guiding optical system can be composed solely of a lens, a compound parabolic concentrator, or a light-guiding column, or any combination of the aforementioned optical elements. The number of lenses, compound parabolic concentrators, and light-guiding columns is determined as needed and can be one, two, or more. The light-guiding column can be solid or hollow, and its end face can be planar or non-planar.

[0115] Preferably, it also includes a second scattering optical system, the second optical path adjusting device allows the light of the second wavelength band emitted by the second light source to be partially transmitted and partially reflected and then emitted from different optical paths, the first scattering optical system receives the light of the second wavelength band emitted from one of the optical paths, and the second scattering optical system receives the light of the second wavelength band emitted from the other optical path, reflects it and forms scattered light of the second wavelength band; the second optical path adjusting device allows the light of the second wavelength band from the second scattering optical system to be transmitted or reflected and then emitted to the dichroic mirror, and the dichroic mirror allows it to be transmitted or reflected.

[0116] Preferably, the second scattering optical system is composed of a second reflective scattering plate, or a second transmissive scattering plate and a second reflecting mirror.

[0117] In the above technical solution, the second reflective scattering plate may be a static or dynamic rotatable second reflective scattering plate.

[0118] Preferably, a third collecting optical system is further included, which is located on the optical path between the second optical path adjusting device and the second scattering optical system, and is used to converge the light of the second wavelength band from the second optical path adjusting device toward the second scattering optical system, and at the same time to collect the light of the second wavelength band from the second scattering optical system and direct it toward the second optical path adjusting device.

[0119] In the above technical solution, the third collecting optical system can be composed of a lens, a lens group, a compound parabolic concentrator or a conical light guide column alone, or can be composed of any combination of the above-mentioned optical elements.

[0120] Preferably, it further comprises a second quarter-wave plate, which is located on the optical path between the second optical path adjusting device and the second scattering optical system.

[0121] Those skilled in the art may also provide a heat sink for dissipating heat from the first light source and / or the second light source and / or the wavelength conversion device as needed.

[0122] In the present invention, the mixing effect of the emitted light can be improved by using a first scattering optical system. The first light source and the second light source in the present invention are independent of each other, so that the color temperature of the emitted light of the light-emitting device can be freely adjusted by adjusting the power of the first light source and the second light source separately, and the output of the luminous flux of the light-emitting device will not be affected. At the same time, a laser that can emit light of different main wavelengths can be used in the second light source to expand the spectrum of the blue light band, thereby improving the color rendering index of the emitted light of the light-emitting device. In addition, the light emitted by the first light source in the present invention is all used to excite the wavelength conversion device. Therefore, compared with the existing technical solutions, the light-emitting device provided in the present invention can achieve a higher luminous flux output without increasing the optical expansion amount. If a polarization selection element is used in conjunction with the first light source, the luminous flux output of the light-emitting device can be further improved without affecting the optical expansion amount of the light-emitting device.

[0123] The light-emitting device of the present invention has the characteristics of high brightness, small optical expansion, high color rendering index, and long working life. It can be used in systems that require high light intensity and small optical expansion, such as entertainment lighting systems, projection systems, automotive lighting systems, medical lighting systems, searchlight lighting systems, field work lighting systems, marine lighting systems, portable lighting systems, etc., and is particularly suitable for use in entertainment lighting systems and projection lighting systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0124] Figure 1 A schematic structural diagram of a conventional light emitting device using a dichroic mirror;

[0125] Figure 2 A schematic diagram of the structure of an existing light emitting device using a polarization beam splitter;

[0126] Figure 3 is a schematic structural diagram of a static wavelength conversion device;

[0127] Figure 4 and Figure 5 Two different structural forms of dynamic wavelength conversion devices are shown;

[0128] Figure 6 This is a schematic structural diagram of a light-emitting device disclosed in Example 1;

[0129] Figure 7 This is a structural schematic diagram of a light-emitting device disclosed in Example 2;

[0130] Figure 8 This is a schematic structural diagram of a light-emitting device disclosed in Example 3;

[0131] Figure 9 This is a schematic structural diagram of a light-emitting device disclosed in Example 4;

[0132] Figure 10 This is a schematic structural diagram of a light-emitting device disclosed in Example 5;

[0133] Figure 11 This is a schematic structural diagram of a light-emitting device disclosed in Example 6;

[0134] Figure 12 This is a schematic structural diagram of a light-emitting device disclosed in Example 7;

[0135] Figure 13 This is a schematic structural diagram of a light-emitting device disclosed in Example 8;

[0136] Figure 14 This is a schematic structural diagram of a light-emitting device disclosed in Example 9;

[0137] Figure 15 This is a schematic structural diagram of a light-emitting device disclosed in Example 10;

[0138] Figure 16 This is a schematic structural diagram of a light-emitting device disclosed in Example 11;

[0139] Figure 17 This is a schematic structural diagram of a light-emitting device disclosed in Example 12;

[0140] Figure 18 This is a schematic structural diagram of a light-emitting device disclosed in Example 13;

[0141] Figure 19 This is a schematic structural diagram of a light-emitting device disclosed in Example 14;

[0142] Figure 20 This is a schematic structural diagram of a light-emitting device disclosed in Example 15;

[0143] Figure 21 This is a schematic structural diagram of a light-emitting device disclosed in Example 16;

[0144] Figure 22 This is a schematic structural diagram of a light-emitting device disclosed in Example 17;

[0145] Figure 23 This is a schematic structural diagram of a light-emitting device disclosed in Example 18;

[0146] Figure 24 This is a schematic structural diagram of a light-emitting device disclosed in Example 19;

[0147] Figure 25 This is a schematic structural diagram of a light-emitting device disclosed in Example 20;

[0148] Figure 26 This is a schematic structural diagram of a light-emitting device disclosed in Example 21;

[0149] Figure 27 This is a schematic structural diagram of a light-emitting device disclosed in Example 22;

[0150] Figure 28 This is a schematic structural diagram of a light-emitting device disclosed in Example 23;

[0151] Figure 29 This is a structural schematic diagram of a light-emitting device disclosed in Example 24. DETAILED DESCRIPTION

[0152] Below in conjunction with specific embodiment, further set forth the present invention.Should be understood that these embodiments are only used to illustrate the present invention and are not used in limiting the scope of the present invention.In addition, should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall equally within the scope limited by the appended claims of the application.

[0153] The structure of the static wavelength conversion device used in the following embodiments can be as follows: Figure 3 The dynamic wavelength conversion device used in the following embodiments may be as follows: Figure 4 The dynamic wavelength conversion device shown can also be Figure 5 The dynamic wavelength conversion device shown.

[0154] like Figure 3 A static wavelength conversion device 301 shown includes a reflective layer 301a and a wavelength conversion layer 301b arranged on the reflective layer 301a, wherein the wavelength conversion layer 301b is composed of a yellow fluorescent material (such as yellow fluorescent powder or yellow fluorescent ceramic), which converts the incident blue light into yellow light, and the reflective layer 301a is a reflective substrate.

[0155] like Figure 4A dynamic wavelength conversion device is shown, a rotatable fluorescent wheel 401, which includes a reflective layer and a wavelength conversion layer Y disposed on the reflective layer. The wavelength conversion layer Y is composed of a yellow fluorescent material (e.g., yellow phosphor or yellow fluorescent ceramic) and converts incident blue light into yellow light.

[0156] like Figure 5 Another dynamic wavelength conversion device shown is a rotatable fluorescent wheel 501. It includes a reflective layer and two different wavelength conversion layers, wavelength conversion layer G and wavelength conversion layer R, disposed on the reflective layer in different sectors of the fluorescent wheel 501. Wavelength conversion layer G is composed of a green fluorescent material (e.g., green phosphor powder or green fluorescent ceramic) and converts incident blue light into green light. Wavelength conversion layer R is composed of a red fluorescent material (e.g., red phosphor powder or red fluorescent ceramic) and converts incident blue light into red light.

[0157] Example 1

[0158] like Figure 6 As shown, a light-emitting device disclosed in this embodiment includes a first light source 601, a second light source 602, a dichroic mirror 603, a first collection optical system, a wavelength conversion device 605, a first optical path adjustment device, a polarization conversion element, a second collection optical system, a first scattering optical system, and a focusing optical system. The first light source 601 includes a plurality of lasers 601a and a plurality of collimating lenses 601b corresponding to the plurality of lasers 601a. ​​The lasers 601a emit blue light with a dominant wavelength of 455 nm. The second light source 602 includes a plurality of lasers 602a and a plurality of collimating lenses 602b corresponding to the plurality of lasers 602a. The lasers 602a emit blue light with a dominant wavelength of 455 nm. The first collection optical system comprises a lens assembly 604 including a lens 604a and a lens 604b. The wavelength conversion device 605 includes a reflective layer 605a and a wavelength conversion layer 605b disposed on the reflective layer 605a. The first optical path adjustment device is a flat-plate polarization beam splitter 606. The polarization conversion element is a quarter-wave plate 607. The second collection optical system is composed of a lens group 608 including a lens 608a and a lens 608b. The first scattering optical system is composed of a reflective scattering plate 609. The collection optical system is composed of a focusing lens 610.

[0159] In this embodiment, the dichroic mirror 603 reflects blue light and transmits yellow light. Blue light emitted by the first light source 601 is reflected by the dichroic mirror 603 and directed toward the lens assembly 604. The lens assembly 604 converges the blue light from the dichroic mirror 603 toward the wavelength conversion device 605. The wavelength conversion device 605 converts the incident blue light into yellow light and directs it toward the lens assembly 604. The yellow light is collected by the lens assembly 604 and directed toward the dichroic mirror 603. The dichroic mirror 603 transmits the yellow light and directs it toward the flat-plate polarization beam splitter 606.

[0160] The flat-plate polarization beam splitter 606 in this embodiment reflects S-polarized blue light and transmits P-polarized blue light. It also transmits yellow light. The P-polarized blue light emitted by the second light source 602 passes through the flat-plate polarization beam splitter 606 and is directed toward the quarter-wave plate 607. After passing through the quarter-wave plate 607, the P-polarized blue light is converted into circularly polarized blue light. The lens group 608 focuses the circularly polarized blue light toward the reflective diffuser 609. The reflective diffuser 609 reflects the incident circularly polarized blue light. The circularly polarized blue light reflected by the reflective diffuser 609 is collected by the lens group 608 and directed toward the quarter-wave plate 607. After passing through the quarter-wave plate 607, the circularly polarized blue light is converted into S-polarized blue light, which is then directed toward the flat-plate polarization beam splitter 606.

[0161] Since the flat-plate polarization beam splitter 606 reflects S-polarized blue light and transmits P-polarized blue light, while also transmitting yellow light, the yellow light transmitted through the flat-plate polarization beam splitter 606 and the S-polarized blue light reflected by the flat-plate polarization beam splitter 606 are combined into a mixed light beam and emitted toward the focusing lens 610. The mixed light beam of yellow light and blue light is white light. Finally, the focusing lens 610 converges the white light and emits it from the light-emitting device.

[0162] Example 2

[0163] like Figure 7As shown, a light emitting device disclosed in this embodiment includes a first light source 701 (composed of a plurality of lasers 701a and a plurality of collimating lenses 701b corresponding to the plurality of lasers 701a), a second light source 702 (composed of a plurality of lasers 702a and a plurality of collimating lenses 702b corresponding to the plurality of lasers 702a), a dichroic mirror 703, a first collecting optical system (composed of a lens group 704 including a lens 704a and a lens 704b), a wavelength conversion device 705 (including a reflector layer 705a and a wavelength conversion layer 705b provided on the reflecting layer 705a), a first optical path adjustment device (composed of a flat-plate polarization splitter 706), a polarization conversion element (composed of a quarter-wave plate 707), a second collecting optical system (composed of a lens group 708 including a lens 708a and a lens 708b), a first scattering optical system (composed of a reflective scattering plate 709), a focusing optical system (composed of a focusing lens 710), a first lens group 711 and a second lens group 712.

[0164] The first difference between this embodiment and Embodiment 1 is that a first lens group 711 is provided on the optical path from the first light source 701 to the dichroic mirror 703. The first lens group 711 is composed of a positive lens 711a and a negative lens 711b, and is used to reduce the light beam formed by the blue light emitted by the first light source 701.

[0165] The second difference between this embodiment and Example 1 is that a second lens group 712 is provided on the optical path from the second light source 702 to the flat-plate polarization beam splitter 706. The second lens group 712 is composed of a positive lens 712a and a negative lens 712b, and is used to reduce the light beam formed by the blue light emitted by the second light source 702.

[0166] Example 3

[0167] like Figure 8As shown, a light-emitting device disclosed in this embodiment includes a first light source 801 (composed of a plurality of lasers 801a and a plurality of collimating lenses 801b corresponding one-to-one to the plurality of lasers 801a), a second light source 802 (composed of a plurality of lasers 802a and a plurality of collimating lenses 802b corresponding one-to-one to the plurality of lasers 802a), a dichroic mirror 803, a first collecting optical system (composed of a lens group 804 including a lens 804a and a lens 804b), a wavelength conversion device 805 (including a reflective layer 805a and a wavelength conversion layer 805b provided on the reflective layer 805a), a first optical path adjustment device, a polarization conversion element (composed of a quarter-wave plate 807), a second collecting optical system (composed of a lens group 808 including a lens 808a and a lens 808b), a first scattering optical system (composed of a reflective scattering plate 809), a focusing optical system (composed of a focusing lens 810), a first uniform light optical system, and a second uniform light optical system.

[0168] The first difference between this embodiment and Embodiment 1 is that the first optical path adjustment device in this embodiment is composed of a cube-type polarization beam splitter 806 instead of a flat-plate polarization beam splitter.

[0169] The second difference between this embodiment and embodiment 1 is that a first light homogenizing optical system is provided on the optical path from the first light source 801 to the dichroic mirror 803 . The first light homogenizing optical system is composed of a transmissive diffuser 813 for homogenizing the blue light emitted by the first light source 801 .

[0170] The third difference between this embodiment and embodiment 1 is that a second light homogenizing optical system is provided on the optical path from the second light source 802 to the cube-shaped polarization beam splitter 806 . The second light homogenizing optical system is composed of a transmissive diffuser 814 for homogenizing the blue light emitted by the second light source 802 .

[0171] Example 4

[0172] like Figure 9As shown, a light-emitting device disclosed in this embodiment includes a first light source 901 (composed of a plurality of lasers 901a and a plurality of collimating lenses 901b corresponding one-to-one to the plurality of lasers 901a), a second light source 902, a dichroic mirror 903, a first collecting optical system (composed of a lens group 904 including a lens 904a and a lens 904b), a wavelength conversion device 905 (comprising a reflective layer 905a and a wavelength conversion layer 905b provided on the reflective layer 905a), a first optical path adjustment device (composed of a flat-plate polarization beam splitter 906), a polarization conversion element (composed of a quarter-wave plate 907), a second collecting optical system (composed of a lens group 908 including a lens 908a and a lens 908b), a first scattering optical system (composed of a reflective scattering plate 909), and a focusing optical system (composed of a focusing lens 910).

[0173] This embodiment differs from Example 1 in that the second light source 902 in this embodiment includes several lasers 902a and corresponding collimating lenses 902b, as well as several lasers 902c and corresponding collimating lenses 902d. Lasers 902a emit blue light with a dominant wavelength of 455nm, while lasers 902c emit blue light with a dominant wavelength of 465nm. Compared to Example 1, the use of lasers emitting blue light with different dominant wavelengths broadens the spectrum of the blue light band, thereby improving the color rendering index of the light emitted by the light-emitting device. Furthermore, since the second light source 902 is not used to excite the wavelength conversion device 905 to produce yellow light, changing the wavelength band of the light emitted by the second light source 902 does not affect the conversion efficiency of the wavelength conversion device 905.

[0174] Example 5

[0175] like Figure 10 As shown, a light-emitting device disclosed in this embodiment includes a first light source 1001, a second light source 1002 (composed of a plurality of lasers 1002a and a plurality of collimating lenses 1002b corresponding one-to-one to the plurality of lasers 1002a), a dichroic mirror 1003, a first collecting optical system (composed of a lens group 1004 including a lens 1004a and a lens 1004b), a wavelength conversion device 1005 (comprising a reflective layer 1005a and a wavelength conversion layer 1005b provided on the reflective layer 1005a), a first optical path adjustment device (composed of a flat-plate polarization beam splitter 1006), a polarization conversion element (composed of a quarter-wave plate 1007), a second collecting optical system (composed of a lens group 1008 including a lens 1008a and a lens 1008b), a first scattering optical system (composed of a reflective scattering plate 1009), and a focusing optical system (composed of a focusing lens 1010).

[0176] This embodiment differs from Example 1 in that the first light source 1001 in this embodiment includes several lasers 1001a and several collimating lenses 1001b corresponding to each of the lasers 1001a, several lasers 1001c and several collimating lenses 1001d corresponding to each of the lasers 1001c, and a polarization-selective element 1001e. Lasers 1001a emit S-polarized blue light, which is incident on one side of the polarization-selective element 1001e, while lasers 1001c emit P-polarized blue light, which is incident on the other side of the polarization-selective element 1001e. The polarization-selective element 1001e reflects S-polarized blue light and transmits P-polarized blue light. The S-polarized blue light emitted by lasers 1001a and the P-polarized blue light emitted by lasers 1001c are combined into one beam by the polarization-selective element 1001e. Compared with Example 1, the first light source 1001 in this embodiment can emit more blue light without affecting the optical etendue of the light-emitting device, so that more yellow light can be obtained after exciting the wavelength conversion device 1005.

[0177] Example 6

[0178] like Figure 11 As shown, a light-emitting device disclosed in this embodiment includes a first light source 1101, a second light source 1102 (composed of a plurality of lasers 1102a and a plurality of collimating lenses 1102b corresponding one-to-one to the plurality of lasers 1102a), a dichroic mirror 1103, a first collecting optical system (composed of a lens group 1104 including a lens 1104a and a lens 1104b), a wavelength conversion device 1105 (comprising a reflective layer 1105a and a wavelength conversion layer 1105b provided on the reflective layer 1105a), a first optical path adjustment device (composed of a flat-plate polarization beam splitter 1106), a polarization conversion element (composed of a quarter-wave plate 1107), a second collecting optical system (composed of a lens group 1108 including a lens 1108a and a lens 1108b), a first scattering optical system (composed of a reflective scattering plate 1109), and a focusing optical system (composed of a focusing lens 1110).

[0179] This embodiment differs from Example 1 in that the first light source 1101 in this embodiment includes a plurality of lasers 1101a and a plurality of collimating lenses 1101b corresponding to the plurality of lasers 1101a, a plurality of lasers 1101c and a plurality of collimating lenses 1101d corresponding to the plurality of lasers 1101c, a polarization-selective element 1101e, and a reflector 1101f. The lasers 1101a emit S-polarized blue light, which is reflected by the reflector 1101f and incident on one side of the polarization-selective element 1101e. The lasers 1101c emit P-polarized blue light, which is incident on the other side of the polarization-selective element 1101e. The polarization-selective element 1101e reflects S-polarized blue light and transmits P-polarized blue light. The S-polarized blue light emitted by laser 1101a and the P-polarized blue light emitted by laser 1101c are combined into one beam by polarization-selective element 1101e. Compared to Example 1, first light source 1101 in this embodiment can emit more blue light without affecting the etendue of the light-emitting device, thereby generating more yellow light after stimulating wavelength conversion device 1105.

[0180] Example 7

[0181] like Figure 12 As shown, a light-emitting device disclosed in this embodiment includes a first light source 1201 (composed of a plurality of lasers 1201a and a plurality of collimating lenses 1201b corresponding one-to-one to the plurality of lasers 1201a), a second light source 1202 (composed of a plurality of lasers 1202a and a plurality of collimating lenses 1202b corresponding one-to-one to the plurality of lasers 1202a), a dichroic mirror 1203, a first collecting optical system (composed of a lens group 1204 including a lens 1204a and a lens 1204b), a wavelength conversion device, a first optical path adjustment device (composed of a flat-plate polarization splitter 1206), a polarization conversion element (composed of a quarter-wave plate 1207), a second collecting optical system (composed of a lens group 1208 including a lens 1208a and a lens 1208b), a first scattering optical system, and a focusing optical system (composed of a focusing lens 1210).

[0182] The first difference between this embodiment and embodiment 1 is that the wavelength conversion device in this embodiment is a rotatable fluorescent wheel 1205 .

[0183] The second difference between this embodiment and embodiment 1 is that the first scattering optical system in this embodiment is a rotatable reflective scattering plate 1209 .

[0184] Example 8

[0185] like Figure 13As shown, a light emitting device disclosed in this embodiment includes a first light source 1301 (composed of a plurality of lasers 1301a and a plurality of collimating lenses 1301b corresponding to the plurality of lasers 1301a), a second light source 1302 (composed of a plurality of lasers 1302a and a plurality of collimating lenses 1302b corresponding to the plurality of lasers 1302a), a dichroic mirror 1303, a first collecting optical system (composed of a lens group 1304 including a lens 1304a and a lens 1304b), and a plurality of collimating lenses 1302b corresponding to the plurality of lasers 1302a. ), a wavelength conversion device 1305 (including a reflection layer 1305a and a wavelength conversion layer 1305b provided on the reflection layer 1305a), a first optical path adjustment device (composed of a flat-plate polarization splitter 1306), a polarization conversion element (composed of a quarter-wave plate 1307), a second collecting optical system (composed of a lens group 1308 including a lens 1308a and a lens 1308b), a first scattering optical system 1309 and a focusing optical system (composed of a focusing lens 1310).

[0186] The difference between this embodiment and embodiment 1 is that the first scattering optical system 1309 in this embodiment is composed of a transmission scattering plate 1309a and a reflecting mirror 1309b.

[0187] Example 9

[0188] like Figure 14 As shown, a light emitting device disclosed in this embodiment includes a first light source 1401 (composed of a plurality of lasers 1401a and a plurality of collimating lenses 1401b corresponding to the plurality of lasers 1401a), a second light source 1402 (composed of a plurality of lasers 1402a and a plurality of collimating lenses 1402b corresponding to the plurality of lasers 1402a), a dichroic mirror 1403, a first collecting optical system (composed of a lens group 1404 including a lens 1404a and a lens 1404b), a wavelength conversion device 1404, and a wavelength conversion device 1405. The device 1405 comprises a reflective layer 1405a and a wavelength conversion layer 1405b provided on the reflective layer 1405a, a first optical path adjustment device (composed of a flat-plate polarization beam splitter 1406), a polarization conversion element (composed of a quarter-wave plate 1407), a second collecting optical system (composed of a lens group 1408 including a lens 1408a and a lens 1408b), a first scattering optical system (composed of a reflective scattering plate 1409), and a focusing optical system (composed of a focusing lens 1410).

[0189] The difference between this embodiment and Example 1 is that the dichroic mirror 1403 in this embodiment has the characteristic of transmitting blue light and reflecting yellow light. The blue light emitted by the first light source 1401 passes through the dichroic mirror 1403 and is emitted to the lens group 1404. The lens group 1404 converges the blue light from the dichroic mirror 1403 toward the wavelength conversion device 1405. The wavelength conversion device 1405 converts the incident blue light into yellow light and emits it to the lens group 1404. The yellow light is collected by the lens group 1404 and emitted to the dichroic mirror 1403. Then, it is reflected by the dichroic mirror 1403 and emitted to the flat-plate polarization beam splitter 1406.

[0190] Example 10

[0191] like Figure 15 As shown, a light emitting device disclosed in this embodiment includes a first light source 1501 (composed of a plurality of lasers 1501a and a plurality of collimating lenses 1501b corresponding to the plurality of lasers 1501a), a second light source 1502 (composed of a plurality of lasers 1502a and a plurality of collimating lenses 1502b corresponding to the plurality of lasers 1502a), a dichroic mirror 1503, a first collecting optical system (composed of a lens group 1504 including a lens 1504a and a lens 1504b), a wavelength conversion device 1506, and a wavelength conversion device 1507. The device 1505 includes a reflective layer 1505a and a wavelength conversion layer 1505b provided on the reflective layer 1505a, a first optical path adjustment device (composed of a flat-plate polarization splitter 1506), a polarization conversion element (composed of a quarter-wave plate 1507), a second collecting optical system (composed of a lens group 1508 including a lens 1508a and a lens 1508b), a first scattering optical system (composed of a reflective scattering plate 1509), and a focusing optical system (composed of a focusing lens 1510).

[0192] This embodiment differs from Example 1 in that the flat-plate polarization beam splitter 1506 in this embodiment reflects S-polarized blue light and transmits P-polarized blue light. Furthermore, the flat-plate polarization beam splitter 1506 also reflects yellow light. The S-polarized blue light emitted by the second light source 1502 is reflected by the flat-plate polarization beam splitter 1506 and then directed toward the quarter-wave plate 1507. After passing through the quarter-wave plate 1507, the S-polarized blue light is converted into circularly polarized blue light. The lens assembly 1508 converges the circularly polarized blue light toward the reflective diffuser 1509, which reflects the incident circularly polarized blue light. The circularly polarized blue light reflected by the reflective diffuser 1509 is collected by the lens assembly 1508 and directed toward the quarter-wave plate 1507. After passing through the quarter-wave plate 1507, the circularly polarized blue light is converted into p-polarized blue light. This p-polarized blue light is then directed toward the flat-plate polarization beam splitter 1506. The flat-plate polarization beam splitter 1506 transmits the p-polarized blue light while reflecting the yellow light from the dichroic mirror 1503. The p-polarized blue light transmitted through the flat-plate polarization beam splitter 1506 and the yellow light reflected by the flat-plate polarization beam splitter 1506 are combined into a mixed light beam that is directed toward the focusing lens 1510.

[0193] Example 11

[0194] like Figure 16 As shown, a light emitting device disclosed in this embodiment includes a first light source 1601 (composed of a plurality of lasers 1601a and a plurality of collimating lenses 1601b corresponding to the plurality of lasers 1601a), a second light source 1602 (composed of a plurality of lasers 1602a and a plurality of collimating lenses 1602b corresponding to the plurality of lasers 1602a), a dichroic mirror 1603, a first collecting optical system (composed of a lens group 1604 including a lens 1604a and a lens 1604b), a wavelength conversion device 1605 (including a reflector layer 1605a and a wavelength conversion layer 1605b provided on the reflecting layer 1605a), a first optical path adjusting device (composed of a flat-plate polarization splitter 1606), a polarization conversion element (composed of a quarter-wave plate 1607), a second collecting optical system (composed of a lens group 1608 including a lens 1608a and a lens 1608b), a first scattering optical system (composed of a reflective scattering plate 1609), a focusing optical system (composed of a focusing lens 1610), a light-guiding optical system 1615 and a reflecting element 1616.

[0195] This embodiment differs from Example 1 in that a light-guiding optical system 1615 and a reflective element 1616 are provided on the optical path from the second light source 1602 to the flat-plate polarization beam splitter 1606. The light-guiding optical system 1615 comprises a positive lens 1615a and a positive lens 1615b. The transmission area of ​​the reflective element 1616 is a light aperture 1616a, and the positive lens 1615b is located at the light aperture 1616a. The P-polarized blue light emitted by the second light source 1602 is guided by the light-guiding optical system 1615 to the flat-plate polarization beam splitter 1606. The flat-plate polarization beam splitter 1606 reflects S-polarized blue light and transmits P-polarized blue light, while also transmitting yellow light. The P-polarized blue light passes through the flat-plate polarization beam splitter 1606 and is then directed to the quarter-wave plate 1607. After passing through quarter-wave plate 1607, p-polarized blue light is converted into circularly polarized blue light. Lens assembly 1608 converges the circularly polarized blue light toward reflective diffuser 1609, which reflects the incident circularly polarized blue light. After reflection from reflective diffuser 1609, some of the blue light becomes unpolarized blue light, while the remainder remains circularly polarized blue light. The blue light is collected by lens assembly 1608 and directed toward quarter-wave plate 1607. It then passes through quarter-wave plate 1607 and enters flat-plate polarization beam splitter 1606. After passing through the quarter-wave plate 1607, the circularly polarized blue light is converted into S-polarized blue light. This S-polarized blue light is reflected by the flat-plate polarization beam splitter 1606. The unpolarized blue light is then separated by the flat-plate polarization beam splitter 1606 into S-polarized blue light and P-polarized blue light. The S-polarized blue light is reflected by the flat-plate polarization beam splitter 1606, while the P-polarized blue light passes through the flat-plate polarization beam splitter 1606 and is emitted toward the reflective element 1616. The reflective element 1616 reflects most of the P-polarized blue light from the flat-plate polarization beam splitter 1606 and directs it back toward the flat-plate polarization beam splitter 1606. The P-polarized blue light then passes through the flat-plate polarization beam splitter 1606 and is emitted toward the quarter-wave plate 1607 again.

[0196] Example 12

[0197] like Figure 17As shown, a light emitting device disclosed in this embodiment includes a first light source 1701 (composed of a plurality of lasers 1701a and a plurality of collimating lenses 1701b corresponding to the plurality of lasers 1701a), a second light source 1702 (composed of a plurality of lasers 1702a and a plurality of collimating lenses 1702b corresponding to the plurality of lasers 1702a), a dichroic mirror 1703, a first collecting optical system (composed of a lens group 1704 including a lens 1704a and a lens 1704b), a wavelength conversion device 1705 (including a reflective layer 170 5a and a wavelength conversion layer 1705b provided on the reflective layer 1705a), a first optical path adjustment device (composed of a flat-plate polarization beam splitter 1706), a polarization conversion element (composed of a quarter-wave plate 1707), a second collection optical system (composed of a lens group 1708 including lenses 1708a and 1708b), a first scattering optical system (composed of a reflective scattering plate 1709), a focusing optical system (composed of a focusing lens 1710), a quarter-wave plate 1717, a third collection optical system, and a second scattering optical system. The third collection optical system is composed of a lens group 1718 including lenses 1718a and 1718b. The second scattering optical system is composed of a reflective scattering plate 1719.

[0198] This embodiment differs from Example 1 in that when the blue light emitted by the second light source 1702 enters the flat-plate polarization beam splitter 1706, the blue light contains an S-polarized light component and a P-polarized light component. Flat-plate polarization beam splitter 1706 separates the blue light into S-polarized blue light and P-polarized blue light, reflecting the S-polarized blue light and transmitting the P-polarized blue light. The optical path of the P-polarized blue light that passes through flat-plate polarization beam splitter 1706 is the same as the optical path of the P-polarized blue light that passes through flat-plate polarization beam splitter 606 in Example 1. The S-polarized blue light reflected by flat-plate polarization beam splitter 1706 is directed toward dichroic mirror 1703, which reflects it and directs it toward quarter-wave plate 1717. After passing through quarter-wave plate 1717, the S-polarized blue light is converted into circularly polarized blue light. Lens group 1718 converges the circularly polarized blue light toward reflective diffuser 1719. Reflective diffuser 1719 reflects the incident circularly polarized blue light. The circularly polarized blue light reflected by reflective diffuser 1719 is collected by lens group 1718 and then directed toward quarter-wave plate 1717. After passing through quarter-wave plate 1717, the circularly polarized blue light is converted into P-polarized blue light. This P-polarized blue light is reflected by dichroic mirror 1703 and then directed toward flat-plate polarization beam splitter 1706, which transmits it.

[0199] In order to show the light path more clearly, Figure 17 In FIG. 1 , the optical path from the second light source 1702 to the reflective scattering plate 1709 and the optical path from the second light source 1702 to the reflective scattering plate 1719 are both indicated by dotted lines.

[0200] Example 13

[0201] like Figure 18 As shown, a light-emitting device disclosed in this embodiment includes a first light source 1801, a second light source 1802, a dichroic mirror 1803, a first collection optical system, a wavelength conversion device 1805, a second optical path adjustment device, a polarization conversion element, a second collection optical system, a first scattering optical system, and a focusing optical system. The first light source 1801 includes a plurality of lasers 1801a and a plurality of collimating lenses 1801b corresponding to the plurality of lasers 1801a. The lasers 1801a emit blue light with a dominant wavelength of 455 nm. The second light source 1802 includes a plurality of lasers 1802a and a plurality of collimating lenses 1802b corresponding to the plurality of lasers 1802a. The lasers 1802a emit blue light with a dominant wavelength of 455 nm. The first collection optical system comprises a lens assembly 1804 comprising lenses 1804a and 1804b. The wavelength conversion device 1805 includes a reflective layer 1805a and a wavelength conversion layer 1805b disposed on the reflective layer 1805a. The second optical path adjustment device is a flat-plate polarization beam splitter 1806. The polarization conversion element is a quarter-wave plate 1807. The second collection optical system comprises a lens assembly 1808 including a lens 1808a and a lens 1808b. The first scattering optical system comprises a reflective scattering plate 1809. The collection optical system comprises a focusing lens 1810.

[0202] In this embodiment, the flat-plate polarization beam splitter 1806 reflects S-polarized blue light and transmits P-polarized blue light. The P-polarized blue light emitted by the second light source 1802 passes through the flat-plate polarization beam splitter 1806 and is directed toward the quarter-wave plate 1807. After passing through the quarter-wave plate 1807, the P-polarized blue light is converted into circularly polarized blue light. The lens group 1808 then focuses the circularly polarized blue light toward the reflective diffuser 1809. The reflective diffuser 1809 reflects the incident circularly polarized blue light. The circularly polarized blue light reflected by the reflective diffuser 1809 is collected by the lens group 1808 and directed toward the quarter-wave plate 1807. The circularly polarized blue light is converted into S-polarized blue light after passing through the quarter-wave plate 1806 and is emitted to the flat-plate polarization beam splitter 1806 . The S-polarized blue light is reflected by the flat-plate polarization beam splitter 1806 and is emitted to the dichroic mirror 1803 .

[0203] In this embodiment, dichroic mirror 1803 transmits blue light and reflects yellow light. Blue light emitted by first light source 1801 passes through dichroic mirror 1803 and is directed toward lens assembly 1804. Lens assembly 1804 converges the blue light from dichroic mirror 1803 toward wavelength conversion device 1805. Wavelength conversion device 1805 converts the incident blue light into yellow light and directs it toward lens assembly 1804. The yellow light is collected by lens assembly 1804 and then directed toward dichroic mirror 1803.

[0204] Since the characteristic of the dichroic mirror 1803 is to transmit blue light and reflect yellow light, the blue light transmitted through the dichroic mirror 1803 and the yellow light reflected by the dichroic mirror 1803 are combined into a mixed light and emitted to the focusing lens 1810. The mixed light of yellow light and blue light is white light. Finally, the focusing lens 1810 converges the white light and emits it from the light-emitting device.

[0205] Example 14

[0206] like Figure 19 As shown, a light emitting device disclosed in this embodiment includes a first light source 1901 (composed of a plurality of lasers 1901a and a plurality of collimating lenses 1901b corresponding to the plurality of lasers 1901a), a second light source 1902 (composed of a plurality of lasers 1902a and a plurality of collimating lenses 1902b corresponding to the plurality of lasers 1902a), a dichroic mirror 1903, a first collecting optical system (composed of a lens group 1904 including a lens 1904a and a lens 1904b), a wavelength conversion device 1905 (including a reflector layer 1905a and a wavelength conversion layer 1905b provided on the reflecting layer 1905a), a second optical path adjustment device (composed of a flat-plate polarization splitter 1906), a polarization conversion element (composed of a quarter-wave plate 1907), a second collecting optical system (composed of a lens group 1908 including a lens 1908a and a lens 1908b), a first scattering optical system (composed of a reflective scattering plate 1909), a focusing optical system (composed of a focusing lens 1910), a first lens group 1911 and a second lens group 1912.

[0207] The first difference between this embodiment and Example 13 is that a first lens group 1911 is provided on the optical path from the first light source 1901 to the dichroic mirror 1903. The first lens group 1911 is composed of a positive lens 1911a and a negative lens 1911b, and is used to reduce the light beam formed by the blue light emitted by the first light source 1901.

[0208] The second difference between this embodiment and Example 13 is that a second lens group 1912 is provided on the optical path from the second light source 1902 to the flat-plate polarization beam splitter 1906. The second lens group 1912 is composed of a positive lens 1912a and a negative lens 1912b, and is used to reduce the light beam formed by the blue light emitted by the second light source 1902.

[0209] Example 15

[0210] like Figure 20 As shown, a light emitting device disclosed in this embodiment includes a first light source 2001 (composed of a plurality of lasers 2001a and a plurality of collimating lenses 2001b corresponding to the plurality of lasers 2001a), a second light source 2002 (composed of a plurality of lasers 2002a and a plurality of collimating lenses 2002b corresponding to the plurality of lasers 2002a), a dichroic mirror 2003, a first collecting optical system (composed of a lens group 2004 including a lens 2004a and a lens 2004b), a wavelength conversion Device 2005 (including a reflective layer 2005a and a wavelength conversion layer 2005b provided on the reflective layer 2005a), a second optical path adjustment device, a polarization conversion element (composed of a quarter-wave plate 2007), a second collecting optical system (composed of a lens group 2008 including a lens 2008a and a lens 2008b), a first scattering optical system (composed of a reflective scattering plate 2009), a focusing optical system (composed of a focusing lens 2010), a first uniform light optical system, and a second uniform light optical system.

[0211] The first difference between this embodiment and embodiment 13 is that the second optical path adjustment device in this embodiment is composed of a cube-type polarization beam splitter 2006 instead of a flat-plate polarization beam splitter.

[0212] The second difference between this embodiment and embodiment 13 is that a first light homogenizing optical system is provided on the optical path from the first light source 2001 to the dichroic mirror 2003. The first light homogenizing optical system is composed of a transmissive diffuser 2013 and is used to uniformly distribute the blue light emitted by the first light source 2001.

[0213] The third difference between this embodiment and Example 13 is that a second light uniformity optical system is provided on the optical path from the second light source 2002 to the cube-shaped polarization beam splitter 2006. The second light uniformity optical system is composed of a transmissive diffuser 2014 and is used to uniformly distribute the blue light emitted by the second light source 2002.

[0214] Example 16

[0215] like Figure 21As shown, a light-emitting device disclosed in this embodiment includes a first light source 2101 (composed of a plurality of lasers 2101a and a plurality of collimating lenses 2101b corresponding one-to-one to the plurality of lasers 2101a), a second light source 2102, a dichroic mirror 2103, a first collecting optical system (composed of a lens group 2104 including a lens 2104a and a lens 2104b), a wavelength conversion device 2105 (including a reflective layer 2105a and a wavelength conversion layer 2105b provided on the reflective layer 2105a), a second optical path adjustment device (composed of a flat-plate polarization beam splitter 2106), a polarization conversion element (composed of a quarter-wave plate 2107), a second collecting optical system (composed of a lens group 2108 including a lens 2108a and a lens 2108b), a first scattering optical system (composed of a reflective scattering plate 2109), and a focusing optical system (composed of a focusing lens 2110).

[0216] This embodiment differs from Example 13 in that the second light source 2102 in this embodiment includes several lasers 2102a and several collimating lenses 2102b corresponding to each of the lasers 2102a, as well as several lasers 2102c and several collimating lenses 2102d corresponding to each of the lasers 2102c. Lasers 2102a emit blue light with a dominant wavelength of 455nm, while lasers 2102c emit blue light with a dominant wavelength of 465nm. Compared to Example 13, the use of lasers emitting blue light with different dominant wavelengths broadens the spectrum of the blue light band, thereby improving the color rendering index of the light emitted by the light-emitting device. Furthermore, since the second light source 2102 is not used to excite the wavelength conversion device 2105 to produce yellow light, changing the wavelength band of the light emitted by the second light source 2102 does not affect the conversion efficiency of the wavelength conversion device 2105.

[0217] Example 17

[0218] like Figure 22As shown, a light-emitting device disclosed in this embodiment includes a first light source 2201, a second light source 2202 (composed of a plurality of lasers 2202a and a plurality of collimating lenses 2202b corresponding one-to-one to the plurality of lasers 2202a), a dichroic mirror 2203, a first collecting optical system (composed of a lens group 2204 including a lens 2204a and a lens 2204b), a wavelength conversion device 2205 (comprising a reflective layer 2205a and a wavelength conversion layer 2205b provided on the reflective layer 2205a), a second optical path adjustment device (composed of a flat-plate polarization beam splitter 2206), a polarization conversion element (composed of a quarter-wave plate 2207), a second collecting optical system (composed of a lens group 2208 including a lens 2208a and a lens 2208b), a first scattering optical system (composed of a reflective scattering plate 2209), and a focusing optical system (composed of a focusing lens 2210).

[0219] This embodiment differs from Example 13 in that the first light source 2201 in this embodiment includes a plurality of lasers 2201a and a plurality of collimating lenses 2201b corresponding to each of the lasers 2201a; a plurality of lasers 2201c and a plurality of collimating lenses 2201d corresponding to each of the lasers 2201c; and a polarization-selective element 2201e. The lasers 2201a emit S-polarized blue light, which is incident on one side of the polarization-selective element 2201e, while the lasers 2201c emit P-polarized blue light, which is incident on the other side of the polarization-selective element 2201e. The polarization-selective element 2201e reflects S-polarized blue light and transmits P-polarized blue light. The S-polarized blue light emitted by the lasers 2201a and the P-polarized blue light emitted by the lasers 2201c are combined into one beam by the polarization-selective element 2201e. Compared with Example 13, the first light source 2201 in this embodiment can emit more blue light without affecting the optical etendue of the light-emitting device, so that more yellow light can be obtained after exciting the wavelength conversion device 2205.

[0220] Example 18

[0221] like Figure 23As shown, a light-emitting device disclosed in this embodiment includes a first light source 2301, a second light source 2302 (composed of a plurality of lasers 2302a and a plurality of collimating lenses 2302b corresponding one-to-one to the plurality of lasers 2302a), a dichroic mirror 2303, a first collecting optical system (composed of a lens group 2304 including a lens 2304a and a lens 2304b), a wavelength conversion device 2305 (including a reflective layer 2305a and a wavelength conversion layer 2305b provided on the reflective layer 2305a), a second optical path adjustment device (composed of a flat-plate polarization splitter 2306), a polarization conversion element (composed of a quarter-wave plate 2307), a second collecting optical system (composed of a lens group 2308 including a lens 2308a and a lens 2308b), a first scattering optical system (composed of a reflective scattering plate 2309) and a focusing optical system (composed of a focusing lens 2310).

[0222] This embodiment differs from Example 13 in that the first light source 2301 in this embodiment includes a plurality of lasers 2301a and a plurality of collimating lenses 2301b corresponding to the plurality of lasers 2301a, a plurality of lasers 2301c and a plurality of collimating lenses 2301d corresponding to the plurality of lasers 2301c, a polarization-selective element 2301e, and a reflector 2301f. The lasers 2301a emit S-polarized blue light, which is reflected by the reflector 2301f and incident on one side of the polarization-selective element 2301e. The lasers 2301c emit P-polarized blue light, which is incident on the other side of the polarization-selective element 2301e. The polarization-selective element 2301e reflects S-polarized blue light and transmits P-polarized blue light. The S-polarized blue light emitted by laser 2301a and the P-polarized blue light emitted by laser 2301c are combined into one beam by polarization-selective element 2301e. Compared to Example 13, first light source 2301 in this embodiment can emit more blue light without affecting the etendue of the light-emitting device, thereby producing more yellow light after stimulating wavelength conversion device 2305.

[0223] Example 19

[0224] like Figure 24As shown, a light-emitting device disclosed in this embodiment includes a first light source 2401 (composed of a plurality of lasers 2401a and a plurality of collimating lenses 2401b corresponding one-to-one to the plurality of lasers 2401a), a second light source 2402 (composed of a plurality of lasers 2402a and a plurality of collimating lenses 2402b corresponding one-to-one to the plurality of lasers 2402a), a dichroic mirror 2403, a first collecting optical system (composed of a lens group 2404 including a lens 2404a and a lens 2404b), a wavelength conversion device, a second optical path adjustment device (composed of a flat-plate polarization splitter 2406), a polarization conversion element (composed of a quarter-wave plate 2407), a second collecting optical system (composed of a lens group 2408 including a lens 2408a and a lens 2408b), a first scattering optical system, and a focusing optical system (composed of a focusing lens 2410).

[0225] The first difference between this embodiment and Example 13 is that the wavelength conversion device in this embodiment is a rotatable fluorescent wheel 2405 .

[0226] The second difference between this embodiment and Example 13 is that the first scattering optical system in this embodiment is a rotatable reflective scattering plate 2409 .

[0227] Example 20

[0228] like Figure 25 As shown, a light emitting device disclosed in this embodiment includes a first light source 2501 (composed of a plurality of lasers 2501a and a plurality of collimating lenses 2501b corresponding to the plurality of lasers 2501a), a second light source 2502 (composed of a plurality of lasers 2502a and a plurality of collimating lenses 2502b corresponding to the plurality of lasers 2502a), a dichroic mirror 2503, a first collecting optical system (composed of a lens group 2504 including a lens 2504a and a lens 2504b), and a plurality of collimating lenses 2502b corresponding to the plurality of lasers 2502a. ), a wavelength conversion device 2505 (including a reflective layer 2505a and a wavelength conversion layer 2505b provided on the reflective layer 2505a), a second optical path adjustment device (composed of a flat-plate polarization splitter 2506), a polarization conversion element (composed of a quarter-wave plate 2507), a second collecting optical system (composed of a lens group 2508 including a lens 2508a and a lens 2508b), a first scattering optical system 2509 and a focusing optical system (composed of a focusing lens 2510).

[0229] The difference between this embodiment and embodiment 13 is that the first scattering optical system 2509 in this embodiment is composed of a transmission scattering plate 2509a and a reflecting mirror 2509b.

[0230] Example 21

[0231] like Figure 26 As shown, a light emitting device disclosed in this embodiment includes a first light source 2601 (composed of a plurality of lasers 2601a and a plurality of collimating lenses 2601b corresponding to the plurality of lasers 2601a), a second light source 2602 (composed of a plurality of lasers 2602a and a plurality of collimating lenses 2602b corresponding to the plurality of lasers 2602a), a dichroic mirror 2603, a first collecting optical system (composed of a lens group 2604 including a lens 2604a and a lens 2604b), a wavelength conversion device 2604, and a wavelength conversion device 2605. The device 2605 comprises a reflective layer 2605a and a wavelength conversion layer 2605b provided on the reflective layer 2605a, a second optical path adjustment device (composed of a flat-plate polarization beam splitter 2606), a polarization conversion element (composed of a quarter-wave plate 2607), a second collecting optical system (composed of a lens group 2608 including a lens 2608a and a lens 2608b), a first scattering optical system (composed of a reflective scattering plate 2609), and a focusing optical system (composed of a focusing lens 2610).

[0232] This embodiment differs from Example 13 in that the second light source 2602 emits S-polarized blue light, which is directed toward a flat-plate polarization beam splitter 2606. Flat-plate polarization beam splitter 2606 reflects the S-polarized blue light emitted by the second light source 2602 and transmits it toward a quarter-wave plate 2607. After passing through the quarter-wave plate 2607, the S-polarized blue light is converted into circularly polarized blue light. A lens assembly 2608 converges the circularly polarized blue light toward a reflective diffuser 2609. The reflective diffuser 2609 reflects the incident circularly polarized blue light. The circularly polarized blue light reflected by the reflective diffuser 2609 is collected by the lens assembly 2608 and directed toward the quarter-wave plate 2607. The circularly polarized blue light is converted into P-polarized blue light after passing through the quarter-wave plate 2607 and is emitted to the flat-plate polarization beam splitter 2606 . The P-polarized blue light is then emitted to the dichroic mirror 2603 after passing through the flat-plate polarization beam splitter 2606 .

[0233] Example 22

[0234] like Figure 27As shown, a light emitting device disclosed in this embodiment includes a first light source 2701 (composed of a plurality of lasers 2701a and a plurality of collimating lenses 2701b corresponding to the plurality of lasers 2701a), a second light source 2702 (composed of a plurality of lasers 2702a and a plurality of collimating lenses 2702b corresponding to the plurality of lasers 2702a), a dichroic mirror 2703, a first collecting optical system (composed of a lens group 2704 including a lens 2704a and a lens 2704b), a wavelength conversion device 2704, and a wavelength conversion device 2705. The device 2705 comprises a reflective layer 2705a and a wavelength conversion layer 2705b provided on the reflective layer 2705a, a second optical path adjustment device (composed of a flat-plate polarization splitter 2706), a polarization conversion element (composed of a quarter-wave plate 2707), a second collecting optical system (composed of a lens group 2708 including a lens 2708a and a lens 2708b), a first scattering optical system (composed of a reflective scattering plate 2709) and a focusing optical system (composed of a focusing lens 2710).

[0235] The difference between this embodiment and Example 13 is that the dichroic mirror 2703 in this embodiment has the characteristic of reflecting blue light and transmitting yellow light. The blue light emitted by the first light source 2701 is reflected by the dichroic mirror 2703 toward the lens group 2704. The lens group 2704 converges the blue light from the dichroic mirror 2703 toward the wavelength conversion device 2705. The wavelength conversion device 2705 converts the incident blue light into yellow light and transmits it toward the lens group 2704. The yellow light is collected by the lens group 2704 and then transmitted toward the dichroic mirror 2703 and is transmitted through the dichroic mirror 2703.

[0236] Example 23

[0237] like Figure 28As shown, a light emitting device disclosed in this embodiment includes a first light source 2801 (composed of a plurality of lasers 2801a and a plurality of collimating lenses 2801b corresponding to the plurality of lasers 2801a), a second light source 2802 (composed of a plurality of lasers 2802a and a plurality of collimating lenses 2802b corresponding to the plurality of lasers 2802a), a dichroic mirror 2803, a first collecting optical system (composed of a lens group 2804 including a lens 2804a and a lens 2804b), a wavelength conversion device 2805 (including a reflector layer 2805a and a wavelength conversion layer 2805b provided on the reflecting layer 2805a), a second optical path adjustment device (composed of a flat-plate polarization splitter 2806), a polarization conversion element (composed of a quarter-wave plate 2807), a second collecting optical system (composed of a lens group 2808 including a lens 2808a and a lens 2808b), a first scattering optical system (composed of a reflective scattering plate 2809), a focusing optical system (composed of a focusing lens 2810), a light-guiding optical system 2815 and a reflecting element 2816.

[0238] This embodiment differs from Example 13 in that a light-guiding optical system 2815 and a reflective element 2816 are provided on the optical path from the second light source 2802 to the flat-plate polarization beam splitter 2806. The light-guiding optical system 2815 comprises a positive lens 2815a and a positive lens 2815b. The transmission area of ​​the reflective element 2816 is a light aperture 2816a, and the positive lens 2815b is located at the light aperture 2816a. The P-polarized blue light emitted by the second light source 2802 is guided by the light-guiding optical system 2815 to the flat-plate polarization beam splitter 2806. The flat-plate polarization beam splitter 2806 reflects the S-polarized blue light and transmits the P-polarized blue light. The P-polarized blue light passes through the flat-plate polarization beam splitter 2806 and is then directed to the quarter-wave plate 2807. After passing through quarter-wave plate 2807, p-polarized blue light is converted into circularly polarized blue light. Lens assembly 2808 converges the circularly polarized blue light toward reflective diffuser 2809, which reflects the incident circularly polarized blue light. After reflection from reflective diffuser 2809, some of the blue light becomes unpolarized blue light, while the remainder remains circularly polarized blue light. The blue light is collected by lens assembly 2808 and directed toward quarter-wave plate 2807. It then passes through quarter-wave plate 2807 and enters flat-plate polarization beam splitter 2806. After passing through the quarter-wave plate 2807, the circularly polarized blue light is converted into S-polarized blue light. This S-polarized blue light is reflected by the flat-plate polarization beam splitter 2806. The unpolarized blue light is then separated by the flat-plate polarization beam splitter 2806 into S-polarized blue light and P-polarized blue light. The S-polarized blue light is reflected by the flat-plate polarization beam splitter 2806, while the P-polarized blue light passes through the flat-plate polarization beam splitter 2806 and is emitted toward the reflective element 2816. The reflective element 2816 reflects most of the P-polarized blue light from the flat-plate polarization beam splitter 2806 and transmits it back toward the flat-plate polarization beam splitter 2806. The P-polarized blue light then passes through the flat-plate polarization beam splitter 2806 and is emitted toward the quarter-wave plate 2807 again.

[0239] Example 24

[0240] like Figure 29As shown, a light emitting device disclosed in this embodiment includes a first light source 2901 (composed of a plurality of lasers 2901a and a plurality of collimating lenses 2901b corresponding to the plurality of lasers 2901a), a second light source 2902 (composed of a plurality of lasers 2902a and a plurality of collimating lenses 2902b corresponding to the plurality of lasers 2902a), a dichroic mirror 2903, a first collecting optical system (composed of a lens group 2904 including a lens 2904a and a lens 2904b), a wavelength conversion device 2905 (including a reflective layer 290 5a and a wavelength conversion layer 2905b provided on the reflective layer 2905a), a second optical path adjustment device (composed of a flat-plate polarization beam splitter 2906), a polarization conversion element (composed of a quarter-wave plate 2907), a second collection optical system (composed of a lens group 2908 including lenses 2908a and 2908b), a first scattering optical system (composed of a reflective scattering plate 2909), a focusing optical system (composed of a focusing lens 2910), a quarter-wave plate 2917, a third collection optical system, and a second scattering optical system. The third collection optical system is composed of a lens group 2918 including lenses 2918a and 2918b. The second scattering optical system is composed of a reflective scattering plate 2919.

[0241] This embodiment differs from Example 13 in that when the blue light emitted by the second light source 2902 enters the flat-plate polarization beam splitter 2906, the blue light contains an S-polarized component and a P-polarized component. The flat-plate polarization beam splitter 2906 separates the blue light into S-polarized blue light and P-polarized blue light, reflecting the S-polarized blue light and transmitting the P-polarized blue light. The optical path of the P-polarized blue light after passing through the flat-plate polarization beam splitter 2906 is the same as the optical path of the P-polarized blue light after passing through the flat-plate polarization beam splitter 1806 in Example 13. The S-polarized blue light reflected by the flat-plate polarization beam splitter 2906 is directed toward a quarter-wave plate 2917. After passing through the quarter-wave plate 2917, the S-polarized blue light is converted into circularly polarized blue light. The lens assembly 2918 converges the circularly polarized blue light toward the reflective scattering plate 2919. The reflective diffuser 2919 reflects the incident circularly polarized blue light. The circularly polarized blue light reflected by the reflective diffuser 2919 is collected by the lens assembly 2918 and directed toward the quarter-wave plate 2917. After passing through the quarter-wave plate 2917, the circularly polarized blue light is converted into P-polarized blue light. This P-polarized blue light is then directed toward the flat-plate polarization beam splitter 2906, which transmits it.

[0242] In order to show the light path more clearly, Figure 29In FIG, the optical path from the second light source 2902 to the reflective scattering plate 2909 and the optical path from the second light source 2902 to the reflective scattering plate 2919 are both represented by dotted lines.

Claims

1. A light emitting device, characterized in that: The invention comprises a first light source, a second light source, a dichroic mirror, a wavelength conversion device, a first light path adjustment device, a first scattering optical system, a second scattering optical system and a first collecting optical system, wherein: The first light source is used to emit light in a first wavelength band; The second light source is used to emit light of a second wavelength band, and the second wavelength band is the same as or different from the first wavelength band; The dichroic mirror receives the light of the first wavelength band emitted by the first light source and transmits or reflects the light; When the dichroic mirror transmits the light of the first wavelength band emitted by the first light source, the wavelength conversion device receives the light of the first wavelength band transmitted through the dichroic mirror, and converts the light into light of a third wavelength band different from both the first wavelength band and the second wavelength band; the dichroic mirror reflects the light of the third wavelength band from the wavelength conversion device; the light of the third wavelength band reflected by the dichroic mirror is emitted to the first optical path adjustment device; When the dichroic mirror reflects the light of the first wavelength band emitted by the first light source, the wavelength conversion device receives the light of the first wavelength band reflected from the dichroic mirror and converts it into light of a third wavelength band different from both the first wavelength band and the second wavelength band; the dichroic mirror transmits the light of the third wavelength band from the wavelength conversion device; the light of the third wavelength band transmitted through the dichroic mirror is emitted to the first optical path adjustment device; The first optical path adjusting device allows the light of the second wavelength band emitted by the second light source to be partially transmitted and partially reflected and then emitted from different optical paths; the first scattering optical system receives the light of the second wavelength band emitted from one of the optical paths; the dichroic mirror receives the light of the second wavelength band emitted from the other optical path and allows the light to be transmitted or reflected and then emitted to the second scattering optical system, and the second scattering optical system reflects the light and forms scattered light of the second wavelength band; the dichroic mirror allows the light of the second wavelength band from the second scattering optical system to be reflected or transmitted and then emitted to the first optical path adjusting device, and the first optical path adjusting device allows the light to be transmitted or reflected; The first scattering optical system receives the light of the second wavelength band transmitted through the first optical path adjusting device, reflects it and forms scattered light of the second wavelength band; the first optical path adjusting device reflects at least part of the light of the second wavelength band from the first scattering optical system; the first optical path adjusting device transmits the light of the third wavelength band from the dichroic mirror; Alternatively, the first scattering optical system receives the light of the second wavelength band reflected from the first optical path adjusting device, reflects it and forms scattered light of the second wavelength band; the first optical path adjusting device transmits at least part of the light of the second wavelength band from the first scattering optical system; the first optical path adjusting device reflects the light of the third wavelength band from the dichroic mirror; The first collecting optical system is located on the optical path between the dichroic mirror and the wavelength conversion device, and is used to converge the light of the first wavelength band from the dichroic mirror toward the wavelength conversion device, and at the same time to collect the light of the third wavelength band from the wavelength conversion device and direct it toward the dichroic mirror.

2. A light emitting device according to claim 1, characterized in that: The first optical path adjustment device is a first polarization beam splitter, and the first polarization beam splitter has the following first characteristic with respect to the incident light of the second wavelength band: it reflects the linear polarized light of the second wavelength band having a first polarization direction and transmits the linear polarized light of the second wavelength band having a second polarization direction, wherein the first polarization direction is different from the second polarization direction; the first polarization beam splitter has the following second characteristic with respect to the incident light of the third wavelength band: it transmits or reflects the light of the third wavelength band.

3. A light emitting device according to claim 1, characterized in that: It also includes a polarization conversion element, which is located on the optical path between the first optical path adjusting device and the first scattering optical system, and is used to change the polarization direction or polarization state of the light of the second wavelength band emitted from the first optical path adjusting device to the first scattering optical system when it is reflected by the first scattering optical system and returns to the first optical path adjusting device.

4. A light emitting device according to claim 3, characterized in that: The polarization conversion element is a first quarter wave plate.

5. A light emitting device according to claim 1, characterized in that: The first light source includes N first lasers and N first collimating elements corresponding to the N first lasers, N≥1, wherein: The first laser is used to emit light in the first wavelength band; The first collimating element is integrated into the first laser or arranged outside the first laser, and is used for collimating the light of the first wavelength band emitted by the first laser.

6. A light emitting device according to claim 5, characterized in that: The first light source also includes a polarization selection element, and the characteristic of the polarization selection element is to reflect the S polarized light of the first band and transmit the P polarized light of the first band. At least one of the first lasers in the first light source is used to emit the S polarized light of the first band to form incident light one, and the remaining first lasers in the first light source are used to emit the P polarized light of the first band to form incident light two. The polarization selection element combines the incident light one and the incident light two into one light and then emits it.

7. A light emitting device according to claim 1, characterized in that: The second light source includes M second lasers and M second collimating elements corresponding to the M second lasers one by one, M≥1, wherein: The second laser is used to emit light in the second wavelength band; The second collimating element is integrated into the second laser or arranged outside the second laser, and is used for collimating the light of the second wavelength band emitted by the second laser.

8. A light emitting device according to claim 1, characterized in that: The first scattering optical system is composed of a first reflective scattering plate, or a first transmissive scattering plate and a first reflecting mirror.

9. A light emitting device according to claim 1, characterized in that: It also includes a second collecting optical system, which is located on the optical path between the first optical path adjusting device and the first scattering optical system, and is used to converge the light of the second wavelength band from the first optical path adjusting device toward the first scattering optical system, and at the same time to collect the light of the second wavelength band from the first scattering optical system and direct it toward the first optical path adjusting device.

10. A light emitting device according to claim 1, characterized in that: The device also includes a first light homogenization optical system, which is located on the optical path from the first light source to the dichroic mirror and is used to homogenize the light of the first wavelength band emitted by the first light source.

11. A light emitting device according to claim 1, characterized in that: It also includes a second light uniforming optical system, which is located on the optical path from the second light source to the first light path adjustment device and is used to uniformly distribute the light of the second wavelength band emitted by the second light source.

12. A light emitting device according to claim 1, characterized in that: It also includes a focusing optical system for converging the light emitted from the first optical path adjusting device.

13. A light emitting device according to claim 1, characterized in that: The device also comprises a first lens group, which is located on the optical path from the first light source to the dichroic mirror and is used for reducing the light beam formed by the light of the first wavelength band emitted by the first light source.

14. A light emitting device according to claim 1, characterized in that: It also includes a second lens group, which is located on the optical path from the second light source to the first optical path adjusting device and is used to reduce the light beam formed by the light of the second wavelength band emitted by the second light source.

15. A light emitting device according to claim 1, characterized in that: It also includes a reflecting element, which is located on the optical path between the second light source and the first optical path adjusting device, and has a transmission area and a reflection area, the transmission area allows the light of the second wavelength band to pass or transmit through, and the reflection area is used to reflect the light of the second wavelength band from the first optical path adjusting device and make at least part of the light therein return to the first optical path adjusting device.

16. A light emitting device according to claim 15, characterized in that: It also includes a light-guiding optical system, which is located on the optical path from the second light source to the first optical path adjusting device, and is used to guide at least part of the light of the second wavelength band emitted by the second light source to pass through or transmit through the transmission area of ​​the reflective element and then be incident on the first optical path adjusting device.

17. A light emitting device according to claim 1, characterized in that: The second scattering optical system is composed of a second reflective scattering plate, or a second transmissive scattering plate and a second reflecting mirror.

18. A light emitting device according to claim 1, characterized in that: It also includes a third collecting optical system, which is located on the optical path between the dichroic mirror and the second scattering optical system, and is used to converge the light of the second wavelength band from the dichroic mirror toward the second scattering optical system, and at the same time to collect the light of the second wavelength band from the second scattering optical system and direct it toward the dichroic mirror.

19. A light emitting device according to claim 1, characterized in that: Also included is a second quarter wave plate, which is located on an optical path between the dichroic mirror and the second scattering optical system.

20. A light emitting device, characterized in that: The invention comprises a first light source, a second light source, a dichroic mirror, a wavelength conversion device, a second light path adjustment device, a first scattering optical system, a second scattering optical system and a first collecting optical system, wherein: The first light source is used to emit light in a first wavelength band; The second light source is used to emit light of a second wavelength band, and the second wavelength band is the same as or different from the first wavelength band; The second optical path adjusting device allows the light of the second wavelength band emitted by the second light source to be partially transmitted and partially reflected and then emitted from different optical paths; the first scattering optical system receives the light of the second wavelength band emitted from one of the optical paths; the second scattering optical system receives the light of the second wavelength band emitted from the other optical path, reflects it and forms scattered light of the second wavelength band; the second optical path adjusting device allows the light of the second wavelength band from the second scattering optical system to be transmitted or reflected and then emitted to the dichroic mirror, and the dichroic mirror allows the light to be transmitted or reflected; The first scattering optical system receives the light of the second wavelength band transmitted through the second optical path adjusting device, reflects it and forms scattered light of the second wavelength band; the second optical path adjusting device reflects at least part of the light of the second wavelength band from the first scattering optical system, and the light of the second wavelength band from the first scattering optical system reflected by the second optical path adjusting device is directed toward the dichroic mirror; Alternatively, the first scattering optical system receives the light of the second wavelength band reflected from the second optical path adjusting device, reflects it and forms scattered light of the second wavelength band; the second optical path adjusting device transmits at least part of the light of the second wavelength band from the first scattering optical system; the light of the second wavelength band from the first scattering optical system transmitted through the second optical path adjusting device is directed toward the dichroic mirror; The dichroic mirror receives the light of the first wavelength band emitted by the first light source and transmits or reflects the light; When the dichroic mirror transmits the light of the first wavelength band emitted by the first light source, the wavelength conversion device receives the light of the first wavelength band transmitted through the dichroic mirror and converts it into light of a third wavelength band different from both the first wavelength band and the second wavelength band; the dichroic mirror reflects the light of the third wavelength band from the wavelength conversion device; the dichroic mirror transmits the light of the second wavelength band from the second optical path adjustment device; When the dichroic mirror reflects the light of the first wavelength band emitted by the first light source, the wavelength conversion device receives the light of the first wavelength band reflected from the dichroic mirror and converts it into light of a third wavelength band different from both the first wavelength band and the second wavelength band; the dichroic mirror transmits the light of the third wavelength band from the wavelength conversion device; the dichroic mirror reflects the light of the second wavelength band from the second optical path adjustment device; The first collecting optical system is located on the optical path between the dichroic mirror and the wavelength conversion device, and is used to converge the light of the first wavelength band from the dichroic mirror toward the wavelength conversion device, and at the same time to collect the light of the third wavelength band from the wavelength conversion device and direct it toward the dichroic mirror.

21. A light emitting device according to claim 20, characterized in that: The second optical path adjustment device is a second polarization beam splitter, which has the following characteristics with respect to the incident light of the second wavelength band: reflecting the linear polarized light of the second wavelength band having a first polarization direction and transmitting the linear polarized light of the second wavelength band having a second polarization direction, wherein the first polarization direction is different from the second polarization direction.

22. A light emitting device according to claim 20, characterized in that: It also includes a polarization conversion element, which is located on the optical path between the second optical path adjusting device and the first scattering optical system, and is used to change the polarization direction or polarization state of the light of the second wavelength band emitted from the second optical path adjusting device to the first scattering optical system when it is reflected by the first scattering optical system and returns to the second optical path adjusting device.

23. A light emitting device according to claim 22, characterized in that: The polarization conversion element is a first quarter wave plate.

24. A light emitting device according to claim 20, characterized in that: The first light source includes N first lasers and N first collimating elements corresponding to the N first lasers, N≥1, wherein: The first laser is used to emit light in the first wavelength band; The first collimating element is integrated into the first laser or arranged outside the first laser, and is used for collimating the light of the first wavelength band emitted by the first laser.

25. A light emitting device according to claim 24, characterized in that: The first light source also includes a polarization selection element, and the characteristic of the polarization selection element is to reflect the S polarized light of the first band and transmit the P polarized light of the first band. At least one of the first lasers in the first light source is used to emit the S polarized light of the first band to form incident light one, and the remaining first lasers in the first light source are used to emit the P polarized light of the first band to form incident light two. The polarization selection element combines the incident light one and the incident light two into one light and then emits it.

26. A light emitting device according to claim 20, characterized in that: The second light source includes M second lasers and M second collimating elements corresponding to the M second lasers one by one, M≥1, wherein: The second laser is used to emit light in the second wavelength band; The second collimating element is integrated into the second laser or arranged outside the second laser, and is used for collimating the light of the second wavelength band emitted by the second laser.

27. A light emitting device according to claim 20, characterized in that: The first scattering optical system is composed of a first reflective scattering plate, or a first transmissive scattering plate and a first reflecting mirror.

28. A light emitting device according to claim 20, characterized in that: It also includes a second collecting optical system, which is located on the optical path between the second optical path adjusting device and the first scattering optical system, and is used to converge the light of the second wavelength band from the second optical path adjusting device toward the first scattering optical system, and at the same time to collect the light of the second wavelength band from the first scattering optical system and direct it toward the second optical path adjusting device.

29. A light emitting device according to claim 20, characterized in that: The device also includes a first light homogenization optical system, which is located on the optical path from the first light source to the dichroic mirror and is used to homogenize the light of the first wavelength band emitted by the first light source.

30. A light emitting device according to claim 20, characterized in that: It also includes a second light homogenization optical system, which is located on the optical path from the second light source to the second light path adjustment device and is used to homogenize the light of the second wavelength band emitted by the second light source.

31. A light emitting device according to claim 20, characterized in that: A light-converging optical system is also included for converging the light emitted from the dichroic mirror.

32. A light emitting device according to claim 20, characterized in that: The device also comprises a first lens group, which is located on the optical path from the first light source to the dichroic mirror and is used for reducing the light beam formed by the light of the first wavelength band emitted by the first light source.

33. A light emitting device according to claim 20, characterized in that: It also includes a second lens group, which is located on the optical path from the second light source to the second optical path adjusting device and is used to reduce the light beam formed by the light of the second wavelength band emitted by the second light source.

34. A light emitting device according to claim 20, characterized in that: It also includes a reflecting element, which is located on the optical path between the second light source and the second optical path adjusting device, and has a transmission area and a reflection area, the transmission area allows the light of the second wavelength band to pass or transmit through, and the reflection area is used to reflect the light of the second wavelength band from the second optical path adjusting device and make at least part of the light therein return to the second optical path adjusting device.

35. A light emitting device according to claim 34, characterized in that: It also includes a light-guiding optical system, which is located on the optical path from the second light source to the second optical path adjusting device, and is used to guide at least part of the light of the second wavelength band emitted by the second light source to pass through or transmit through the transmission area of ​​the reflective element and then be incident on the second optical path adjusting device.

36. A light emitting device according to claim 20, characterized in that: The second scattering optical system is composed of a second reflective scattering plate, or a second transmissive scattering plate and a second reflecting mirror.

37. A light emitting device according to claim 20, characterized in that: It also includes a third collecting optical system, which is located on the optical path between the second optical path adjusting device and the second scattering optical system, and is used to converge the light of the second wavelength band from the second optical path adjusting device toward the second scattering optical system, and at the same time to collect the light of the second wavelength band from the second scattering optical system and direct it toward the second optical path adjusting device.

38. A light emitting device according to claim 20, characterized in that: It also includes a second quarter-wave plate, which is located on the optical path between the second optical path adjusting device and the second scattering optical system.

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