Prism assembly, light emitting device and projection system

Abstract

The present application discloses a prism assembly, a light emitting device and a projection system. The prism in the prism assembly includes a light incident surface, a functional surface opposite to the light incident surface and a beam splitter element disposed between the light incident surface and the functional surface; wherein the incident light is transmitted to the beam splitter element via the light incident surface, and the beam splitter element is used to reflect at least part of the incident light out of the prism. The present application allows the angular distribution of the incident light to remain unchanged when propagating in the prism, so as to reduce the area of ​​the beam splitter element, reduce the dilution of the expansion amount, and improve the efficiency of the light source.

Description

Technical Field

[0001] The present application relates to the technical field of light-emitting devices, and in particular to a prism assembly, a light-emitting device and a projection system. Background Art

[0002] At present, the application of laser light sources has been paid more and more attention by people. Laser has the advantages of high brightness and long life, but its spectrum is very narrow. At the same time, the high coherence of laser makes the speckle effect of the projected image more obvious, which seriously affects the imaging quality. Therefore, in use, laser is often used to excite fluorescent materials to form mixed light.

[0003] In the prior art, due to the structural configuration of the light-emitting device, the mixed light formed in the light-emitting device has a long distance to enter the subsequent optical system, which dilutes the optical extension and makes the energy cannot be fully utilized by the optical machine, ultimately resulting in low efficiency of the light source. Summary of the invention

[0004] The present application proposes a prism assembly, a light emitting device and a projection system, so that the angular distribution of the incident light does not change when propagating in the prism, so as to reduce the area of ​​the light splitting element, reduce the dilution of the expansion amount, and improve the efficiency of the light source.

[0005] To solve the above-mentioned purpose, the present application provides a prism assembly, wherein the prism assembly includes a prism, wherein the prism includes a light incident surface, a functional surface opposite to the light incident surface, and a beam splitting element disposed between the light incident surface and the functional surface;

[0006] The incident light is transmitted to the beam splitter element via the light incident surface, and the beam splitter element is used to reflect at least part of the incident light out of the prism, and the remaining incident light reaches the functional surface after passing through the beam splitter element.

[0007] Wherein, the prism assembly further comprises an optical processing element arranged on the functional surface;

[0008] The beam splitter element is used to reflect part of the incident light out of the prism and transmit the remaining part of the incident light to form bypass light and irradiate the optical processing element; the bypass light is processed by the optical processing element and then returns to the beam splitter element, and then reflected out of the prism by the beam splitter element.

[0009] Wherein, the optical processing element includes a reflector.

[0010] The beam splitter element is a polarization beam splitter element, which is used to reflect incident light in a first polarization state and transmit incident light in a second polarization state to form the bypass light and irradiate the bypass light to the optical processing element;

[0011] The optical processing element includes a reflector and a quarter wave plate. The quarter wave plate is located between the reflector and the polarization splitter element. The quarter wave plate and the reflector cooperate to change the polarization direction of the bypass light so that the bypass light with changed polarization direction can be reflected out of the prism by the polarization splitter element.

[0012] The prism includes four side surfaces connecting the light incident surface and the functional surface, the four side surfaces are respectively perpendicular to the light incident surface and the functional surface, and at least one group of opposite side surfaces are parallel to each other.

[0013] To solve the above-mentioned purpose, the present application proposes a light emitting device, which includes a light source, a prism assembly and a wavelength conversion device;

[0014] The light source is used to emit excitation light;

[0015] The prism assembly includes a prism, the prism includes a light incident surface, a functional surface opposite to the light incident surface, and a beam splitter element arranged between the light incident surface and the functional surface, and a light source is arranged on one side of the light incident surface of the prism;

[0016] The wavelength conversion device is used for absorbing the excitation light and emitting the excited light propagating toward the prism under the stimulation;

[0017] The excitation light of the light source is transmitted to the spectroscopic element arranged in the prism through the light incident surface of the prism. The spectroscopic element is used to emit at least part of the excitation light to the wavelength conversion device, and the remaining excitation light reaches the functional surface after transmitting the spectroscopic element.

[0018] Wherein, the light emitting device also includes a light homogenizing device;

[0019] The light homogenizing device is arranged between the light source and the prism, and the light emitting surface of the light homogenizing device is close to the light incident surface of the prism; the light incident surface area of ​​the prism matches the size of the light spot emitted by the light homogenizing device.

[0020] Wherein, the prism assembly further comprises an optical processing element arranged on the functional surface, and the light splitting element is located between the optical processing device and the light incident surface;

[0021] The spectroscopic element is used to reflect part of the excitation light to the wavelength conversion device, and transmit the remaining part of the excitation light to form bypass light and irradiate the optical processing element; the bypass light is processed by the optical processing element and then returns to the spectroscopic element, and is reflected by the spectroscopic element to form the second output light.

[0022] The beam splitter is a polarization beam splitter, which is used to reflect the excitation light of the first polarization state to at least part of the light emitted by the wavelength conversion device, vertically enter one side of the prism, and emit through another side of the prism parallel to the side, and transmit the excitation light of the second polarization state to form bypass light and irradiate the optical processing element;

[0023] The optical processing device includes a reflector and a quarter wave plate, wherein the quarter wave plate is located between the reflector and the polarization splitter element, and the quarter wave plate and the reflector cooperate to change the polarization direction of the bypass light so that the bypass light with changed polarization direction can be reflected by the polarization splitter element to form a second output light.

[0024] At least part of the light emitted by the wavelength conversion device is vertically incident on one side surface of the prism, and is emitted through another side surface of the prism that is parallel to and opposite to the side surface.

[0025] To achieve the above objectives, the present application provides a projection system, which includes the above prism assembly and / or the above light-emitting device.

[0026] In the present application, the incident light is transmitted through the light incident surface of the prism to the spectroscopic element disposed between the light incident surface and the functional surface. The angular distribution of the incident light does not change when propagating in the prism, and the area of ​​the spectroscopic element can be reduced, thereby reducing the dilution of the expansion amount and improving the efficiency of the light source. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0028] Figure 1 is a schematic diagram of the structure of the prism assembly of the present application;

[0029] Figure 2 It is a structural schematic diagram of an implementation method of a prism assembly of the present application;

[0030] Figure 3 is a schematic structural diagram of an embodiment of the light emitting device of the present application;

[0031] Figure 4 It is a structural schematic diagram of an embodiment of a wavelength conversion device in the light-emitting device of the present application;

[0032] Figure 5 It is a structural schematic diagram of another embodiment of the light emitting device of the present application. DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0034] In one aspect, the present application provides a prism assembly. Figure 1 The prism 12 in the prism assembly 10 includes a light incident surface 121 and a functional surface 122. The functional surface 122 is opposite to the light incident surface 121. The spectroscopic element 13 is arranged between the light incident surface 121 and the functional surface 122. The incident light is transmitted to the spectroscopic element 13 via the light incident surface 121. The spectroscopic element 13 is used to reflect at least part of the incident light out of the prism 12. Specifically, a bevel may be provided inside the prism 12, and a spectroscopic film may be coated on the entire bevel to form the spectroscopic element 13. Optionally, the bevel may be set at an inclination angle of 45°. Of course, the setting angle of the bevel is not limited thereto. For example, the bevel may also be set at an inclination angle of 30°.

[0035] Optionally, the beam splitter 13 may be a polarization beam splitter, wherein the polarization beam splitter may have polarization beam splitting characteristics only for light with the same polarization state as the incident light, thereby preventing light with a different luminous color or polarization state from the incident light from being polarized and split by the beam splitter 13, and preventing light with a different luminous color or polarization state from the incident light from not being able to fully pass through the beam splitter 13.

[0036] Optionally, the spectroscopic element 13 may be a wavelength spectroscopic element. The wavelength spectroscopic element may have a wavelength spectroscopic characteristic only for light with the same luminous color or luminous wavelength as the incident light, thereby preventing light with a different luminous color or luminous wavelength from the incident light from being wavelength-split by the spectroscopic element 13, and preventing light with a different luminous color or luminous wavelength from the incident light from not being able to fully pass through the spectroscopic element 13. For example, the spectroscopic element 13 may be a reflector. The reflector may have a reflective spectroscopic characteristic only for light with the same luminous color or luminous wavelength as the incident light, thereby preventing light with a different luminous color or luminous wavelength from the incident light from not being able to fully pass through the spectroscopic element 13.

[0037] The prism assembly 10 of the present application may further include an optical processing element 17. The beam splitter element 13 may be used to reflect part of the incident light out of the prism 12, and transmit the remaining part of the incident light to form bypass light and irradiate the optical processing element 17. The optical processing element 17 is used to process the bypass light and return it to the beam splitter element 13, and reflect it out of the prism 12 through the beam splitter element 13.

[0038] The optical processing element 17 is disposed on the functional surface of the prism 12. The beam splitter element 13 is located between the optical processing element 17 and the light incident surface. In this way, the beam splitter element 13 reflects part of the incident light out of the prism 12, and transmits the remaining part of the incident light to form bypass light and irradiate the optical processing element 17. The optical processing element 17 can process the bypass light and return it to the beam splitter element 13, and reflect it out of the prism 12 through the beam splitter element 13.

[0039] In order to fully utilize the incident light transmitted through the spectroscopic element 13 , the configuration of the optical processing element 17 can be reasonably adjusted based on the spectroscopic principle of the spectroscopic element 13 .

[0040] In one implementation, the beam splitter 13 is a polarization beam splitter. Since the polarization state of the incident light may be impure, part of the incident light may pass through the beam splitter 13, resulting in light energy loss and reduced light source efficiency. The optical processing element 17 can change the polarization state of the incident light passing through the beam splitter 13, so that the light energy after the polarization state is changed can be reflected by the beam splitter 13, thereby improving the light source efficiency. Specifically, Figure 2 As shown, the optical processing element 17 in this embodiment may include a reflector 171 and a 1 / 4 wave plate 172, and the 1 / 4 wave plate 172 is located between the reflector 171 and the spectrometer 13. The 1 / 4 wave plate 172 and the reflector 171 are used to change the polarization direction of the bypass light so that the bypass light with the changed polarization direction can be reflected by the spectrometer 13 out of the prism 12.

[0041] The beam splitter element 13 may be an inverted p-transmitting s-polarization beam splitter element or an inverted s-transmitting p-polarization beam splitter element.

[0042] Exemplarily, the incident light is blue light, and the spectrometer 13 is a polarization spectrometer element that reflects s-polarized blue light and transmits p-polarized blue light. The p-blue light will be converted into circularly polarized light when passing through the 1 / 4 wave plate 172 for the first time, and will pass through the 1 / 4 wave plate 172 again after being reflected by the reflector 171. At this time, the circularly polarized light will be converted into s-blue light and will be incident on the spectrometer 13 along the original optical path, and will be reflected out of the prism 12 by the spectrometer 13. In this way, the p-blue light transmitted through the spectrometer 13 can be converted into s-blue light and returned to the spectrometer 13, so as to make full use of the p-blue light transmitted through the spectrometer 13.

[0043] In addition, when the beam splitter 13 is a polarization beam splitter, in order to ensure that the beam splitter 13 reflects at least most of the incident light out of the prism 12, the polarization direction of most of the incident light is the same as the polarization direction of the light reflected by the beam splitter 13. For example, if at least most of the incident light is s light, then the beam splitter 13 can reflect the s incident light and transmit the p incident light.

[0044] In another implementation, the beam splitter element 13 is a wavelength beam splitter element, and further, the beam splitter element 13 can be a reflector. The optical processing element 17 can only include a reflector 171. In this way, the reflector 171 can reflect the bypass light to the beam splitter element 13, and the beam splitter element 13 can reflect at least part of the bypass light out of the prism 12, so that the excitation light passing through the beam splitter element 13 can be fully utilized, and the configuration of the optical processing element 17 is very simple.

[0045] The reflectivity of the reflective sheet can be adjusted as required. Optionally, the reflectivity of the reflective sheet is 50%, 60%, 70%, 80% or 90%.

[0046] In summary, in this embodiment, the incident light is transmitted through the light incident surface of the prism 12 to the spectroscopic element 13 disposed between the light incident surface 121 and the functional surface 122. The angular distribution of the incident light does not change when propagating in the prism 12, and the area of ​​the spectroscopic element 13 can be reduced, thereby reducing the dilution of the expansion amount and improving the efficiency of the light source.

[0047] In addition, the prism 12 may further include a side surface connecting the light incident surface 121 and the functional surface 122. Furthermore, the light incident surface 121, the functional surface 122 and the side surface of the prism 12 may all be optical planes.

[0048] The number of the side surfaces can be adjusted according to the specific situation. Preferably, the prism 12 includes at least four side surfaces. More preferably, the prism 12 includes four side surfaces. Most preferably, the prism 12 is a rectangular parallelepiped.

[0049] Among them, at least one group of opposite side surfaces are parallel to each other. In this way, light vertically enters one side surface of the prism 12 and can be vertically emitted through the other side surface of the prism 12 that is parallel to the side surface, so that the distance of light propagation in the prism 12 can be as consistent as possible, and the uniformity of light propagating through the prism 12 can be improved. At the same time, since the vertical emission does not cause a further increase in optical etendue, it is convenient for subsequent optical elements to collect and utilize the light beam. More preferably, all groups of opposite side surfaces are parallel to each other.

[0050] Optionally, two adjacent side surfaces may also be perpendicular to each other.

[0051] Furthermore, the side surfaces may be perpendicular to the light incident surface and the functional surface respectively.

[0052] In another aspect, the present application provides a light emitting device. Figure 3 As shown, the light emitting device 1 includes a light source 11, a prism assembly 10 of the above-mentioned embodiment, and a wavelength conversion device 14. The light source 11 is used to emit excitation light. The light source 11 is arranged on one side of the light incident surface of the prism 12. A spectroscopic element 13 is arranged in the prism 12. The excitation light of the light source 11 is transmitted to the spectroscopic element 13 arranged in the prism 12 via the light incident surface of the prism 12, and the spectroscopic element 13 is used to emit at least part of the excitation light to the wavelength conversion device 14, and the wavelength conversion device 14 is used to absorb the excitation light and stimulatedly emit the stimulated light propagating toward the prism 12.

[0053] The light source 11 is used to emit excitation light. The light source 11 may be a laser light source including one luminous color. The excitation light emitted by the light source 11 is absorbed and excited by the wavelength conversion device 14 to generate a stimulated light, and the excitation light and the stimulated light are combined to form a first emitted light. The stimulated light may include at least two colors of light or a composite light of at least two colors of light, so that the stimulated light and the excitation light can be combined to form a white emitted light.

[0054] Exemplarily, the light source 11 may be a blue laser light source array composed of a plurality of blue lasers, the blue excitation light is absorbed and excited by the wavelength conversion device 14 to generate green stimulated light and red stimulated light, and the green stimulated light, the red stimulated light, and the blue excitation light may be combined to form white output light. It is understandable that the light source 11 may not be limited to a blue light source, but may also be a purple light source, a red light source, or a green light source, etc.

[0055] In this embodiment, the excitation light emitted by the light source 11 is transmitted to the spectroscopic element 13 arranged in the middle of the prism 12 via the light incident surface of the prism 12. The angular distribution of the excitation light does not change when propagating in the prism 12, and the area of ​​the spectroscopic element 13 can be reduced, thereby reducing the distance that the excited light enters the subsequent optical system, reducing the dilution of the expansion amount, and improving the efficiency of the light source.

[0056] Specifically, a bevel may be provided in the middle of the prism 12, and a spectroscopic film may be coated on the entire bevel to form a spectroscopic element 13. Optionally, the bevel may be provided at a 45° inclination. Of course, the setting angle of the bevel is not limited thereto, and may be determined specifically according to the setting positions of the light source 11 and the wavelength conversion device 14.

[0057] Optionally, the beam splitter 13 may be a polarization beam splitter, wherein the polarization beam splitter is used to reflect the excitation light of the first polarization state to the wavelength conversion device, transmit the excitation light of the second polarization state to form the bypass light and irradiate the optical processing element, thereby preventing the converted light from being polarized and split by the beam splitter 13, resulting in the converted light not being able to completely pass through the beam splitter 13.

[0058] Optionally, the spectroscopic element 13 may be a wavelength spectroscopic element. The wavelength spectroscopic element may have a wavelength spectroscopic characteristic only for light with the same luminous color or luminous wavelength as the excitation light, thereby preventing the converted light from being wavelength-split by the spectroscopic element 13, resulting in the converted light not being able to fully pass through the spectroscopic element 13. For example, in other implementations, the spectroscopic element 13 may be a reflector. The reflector may have a reflective spectroscopic characteristic only for light with the same luminous color or luminous wavelength as the excitation light, thereby preventing the converted light from being reflected and split by the spectroscopic element 13, resulting in the converted light not being able to fully pass through the spectroscopic element 13.

[0059] The light splitting element 13 is used to reflect at least a portion of the excitation light to the wavelength conversion device 14 .

[0060] The wavelength conversion device 14 absorbs the excitation light and generates stimulated light that propagates toward the prism 12 .

[0061] The wavelength conversion device 14 may be circular, square or other shapes, which are not limited here. This embodiment is described by taking a circular shape as an example.

[0062] The wavelength conversion device 14 may include a conversion area, a non-conversion area, and a driving device disposed at the bottom of the wavelength conversion device 14. The conversion area and the non-conversion area are alternately located on the optical path of the excitation light emitted by the light source 11 under the action of the driving unit.

[0063] The conversion area and the non-conversion area can be located in partial areas of the same circular ring respectively, and after being spliced ​​together, a circular ring with a through hole in the center is formed.

[0064] The switching area and the non-switching area may be arranged continuously or discontinuously.

[0065] In order to enable the conversion zone to absorb the excitation light and stimulate the generation of converted light, at least one wavelength conversion material may be disposed on the conversion zone to generate at least one color of converted light under the stimulation of the excitation light.

[0066] Among them, the wavelength conversion material can be fluorescent powder, quantum dot material and phosphorescent material.

[0067] In addition, the luminescent color of the wavelength conversion material can be set according to the color of the excitation light, so that the excitation light and the converted light of at least one color emitted by the wavelength conversion device 14 can be combined to form white output light.

[0068] For example, when the color of the excitation light is blue, the luminous color of the wavelength conversion material is yellow-green. Alternatively, when the color of the excitation light is blue, the luminous color of the wavelength conversion material is red and green. It is understandable that in addition to red and green, and yellow-green, the luminous color of the wavelength conversion material can also be other colors, which are not limited here.

[0069] It can be understood that, in order to facilitate the arrangement of the wavelength conversion device 14, when the number of luminescent colors of the wavelength conversion material is at least two, the conversion area can be divided into at least two sub-conversion areas, and each wavelength conversion material is arranged on each sub-conversion area in a one-to-one correspondence. For example, the wavelength conversion material arranged on the wavelength conversion device 14 includes a red wavelength conversion material and a green wavelength conversion material, and the conversion area is also correspondingly divided into a first sub-conversion area and a second sub-conversion area, the red wavelength conversion material is arranged on the first sub-conversion area, and the green wavelength conversion material is arranged on the second sub-conversion area.

[0070] The sub-conversion regions may be arranged continuously or discontinuously.

[0071] In addition, the areas of different sub-conversion regions may be equal or unequal.

[0072] In this embodiment, the structure of the wavelength conversion device 14 is as follows: Figure 4 As shown, the cross-section of the wavelength conversion device 14 is circular, the first sub-conversion area 141, the second sub-conversion area 142 and the non-conversion area 143 are all continuously distributed arc areas, and the center of each arc area is the rotation center of the wavelength conversion device 14, and the sum of the central angle radii of the first sub-conversion area 141, the second sub-conversion area 142 and the non-conversion area 143 is 360 degrees.

[0073] Furthermore, in order to improve the uniformity of the light spot incident on the light incident surface of the prism 12, the light emitting device 1 may further include a light homogenizing device 16 disposed between the light source 11 and the prism 12. The light homogenizing device 16 is used to shape the angular distribution of the excitation light emitted by the light source 11 to produce a uniformly distributed light spot. Optionally, the light homogenizing device 16 is a double compound eye or a light homogenizing rod, but is not limited thereto.

[0074] Furthermore, the light output surface of the light homogenizing device 16 is close to the light input surface of the prism 12, or is directly attached to the light input surface of the prism 12, and the area of ​​the light input surface of the prism 12 matches the size of the light spot emitted by the light homogenizing device 16. In this way, the area of ​​the spectroscopic element 13 in the prism 12 can be minimized, thereby further reducing the distance that the first output light enters the subsequent optical system, and can reduce the amount of light reflected by the spectroscopic element 13 when the first output light passes through the prism 12, thereby further improving the efficiency of the light source.

[0075] The inventor of the present application discovered that when the first emitted light reaches the area of ​​the spectroscopic element 13, the stimulated light and a part of the excitation light pass through the spectroscopic element 13, and the other part of the excitation light will be reflected by the spectroscopic element 13, so that a part of the excitation light cannot pass through the spectroscopic element 13, resulting in the color of the emitted light leaving the area of ​​the spectroscopic element 13 not being consistent with the preset color, that is, the first emitted light leaving the area of ​​the spectroscopic element 13 has a color unevenness phenomenon. For example, when the excitation light is blue light, a part of the blue light cannot pass through the spectroscopic element 13, resulting in the luminous color of the first emitted light leaving the area of ​​the spectroscopic element 13 being yellowish. When the first emitted light reaches the area outside the spectroscopic element 13, both the stimulated light and the excitation light can pass through and will not be reflected. Because the effect of the spectroscopic element 13 causes only the spectroscopic element 13 area to reflect a part of the excitation light, the luminous colors of the first emitted light leaving the area of ​​the spectroscopic element 13 and the area outside the spectroscopic element 13 are inconsistent, resulting in the first emitted light leaving the prism 12 area having a color unevenness phenomenon, which will lead to the color of the final projected picture being uneven.

[0076] In order to solve the problem of uneven color of the first output light leaving the prism 12 area, the prism assembly of the present application further includes an optical processing element 17, which is used to process the excitation light emitted from the light source 11 and passed through the spectroscopic element 13 and return it to the spectroscopic element 13, so that the spectroscopic element 13 reflects this part of the light and forms a second output light. The first output light can be combined with the second output light to be output, which can not only utilize the excitation light passing through the spectroscopic element 13, but also can use the second output light to reduce the color unevenness of the light emitted by the light-emitting device 1, thereby improving the efficiency of the light source.

[0077] The optical processing element 17 is disposed on the functional surface of the prism 12. The beam splitter element 13 is located between the optical processing element 17 and the light incident surface. In this way, when the beam splitter element 13 reflects part of the excitation light to the wavelength conversion device 14 and transmits the remaining part of the excitation light to form bypass light and irradiates the optical processing element 17, the optical processing element 17 can process the bypass light and return it to the beam splitter element 13, which is reflected by the beam splitter element 13 to form a second output light, so as to reduce the problem of uneven color of the light emitted by the light emitting device 1 and improve the light source efficiency.

[0078] In order to fully utilize the excitation light transmitted through the spectroscopic element 13 , the configuration of the optical processing element 17 can be reasonably adjusted based on the spectroscopic principle of the spectroscopic element 13 .

[0079] In another implementation of the present application, the beam splitter 13 is a polarization beam splitter. Since the polarization state of the excitation light emitted by the light source 11 may be impure, part of the excitation light may pass through the beam splitter 13, resulting in light energy loss and reduced light source efficiency. The optical processing element 17 can change the polarization state of the excitation light passing through the beam splitter 13, so that the light energy after the polarization state is changed can be reflected by the beam splitter 13 and form a second output light, thereby improving the light source efficiency. Specifically, Figure 5 As shown, the optical processing element 17 may include a reflector 171 and a quarter wave plate 172. The quarter wave plate 172 is located between the reflector 171 and the spectrometer 13. The quarter wave plate 172 and the reflector 171 cooperate to change the polarization direction of the bypass light so that the bypass light with the changed polarization direction can be reflected by the spectrometer 13 to form a second output light.

[0080] The spectrometer 13 may be a polarization spectrometer that reflects p-excitation light and transmits s-excitation light, or a polarization spectrometer that reflects s-excitation light and transmits p-excitation light.

[0081] Exemplarily, the excitation light is blue light, and the spectrometer 13 is a polarization spectrometer that reflects s-polarized blue light and transmits p-polarized blue light. The p-blue light will be converted into circularly polarized light when passing through the 1 / 4 wave plate 172 for the first time, and will pass through the 1 / 4 wave plate 172 again after being reflected by the reflector 171. At this time, the circularly polarized light will be converted into s-blue light and enter the spectrometer 13 along the original light path, and will be reflected by the spectrometer 13 to form a second output light. In this way, the p-blue light transmitted through the spectrometer 13 can be converted into s-blue light and returned to the spectrometer 13, so as to make full use of the p-blue light transmitted through the spectrometer 13.

[0082] In addition, when the beam splitter 13 is a polarization beam splitter, in order to ensure that the beam splitter 13 reflects at least most of the excitation light emitted by the light source 11 to the wavelength conversion device 14, the polarization direction of most of the excitation light emitted by the light source 11 is the same as the polarization direction of the light reflected by the beam splitter 13. For example, if at least most of the excitation light emitted by the light source 11 is s light, then the beam splitter 13 can reflect s excitation light and transmit p excitation light.

[0083] In another implementation, the beam splitter element 13 is a wavelength beam splitter element, and further, the beam splitter element 13 can be a reflector. The optical processing element 17 can only include a reflector 171. In this way, the reflector 171 can reflect the bypass light onto the beam splitter element 13, and the beam splitter element 13 can reflect at least part of the bypass light and form a second output light, which can fully utilize the excitation light passing through the beam splitter element 13, and the configuration of the optical processing element 17 is very simple.

[0084] The reflectivity of the reflective sheet can be adjusted as required. Optionally, the reflectivity of the reflective sheet is 50%, 60%, 70%, 80% or 90%.

[0085] Furthermore, the light emitting device 1 may also include a first collecting device 18 located between the light homogenizing device 16 and the light source 11. The first collecting device 18 is used to collect the excitation light and then inject it into the light homogenizing device 16, which can compress the light spot size, further reduce the area of ​​the light splitting element 13, reduce the distance of the first emitted light entering the subsequent optical system, and improve the light source efficiency. Optionally, the first collecting device 18 can be a positive and negative lens group.

[0086] In addition, the light-emitting device 1 may also include a second collecting device 19 located between the spectroscopic element 13 and the wavelength conversion device 14, which is used to change the surface angle of the excitation light reflected by the spectroscopic element 13, image it on the wavelength conversion device 14, and then converge the first output light formed by the wavelength conversion device 14 and emit it.

[0087] Optionally, the second collecting device 19 may be a collecting lens. The second collecting device 19 may be closely attached to the side of the prism 12, and since the area of ​​the light splitting element 13 is relatively small, this will reduce the distance that the light emitted by the second collecting device 19 enters the subsequent optical system, so that the light spot entering the subsequent optical system is reduced, thereby reducing the size of the solid angle at the panel and improving the efficiency of the system passing through the lens.

[0088] In addition, the light emitted by the second collecting device 19 can be vertically incident on one side of the prism 12 and emitted from the other side of the prism 12; and one side of the prism 12 and the other side of the prism 12 are parallel to each other, so that the distance that the light emitted by the second collecting device 19 propagates in the prism 12 can be as consistent as possible, so that the light emitted by the light-emitting device 1 is more uniform.

[0089] The above are embodiments of the light-emitting device 1 provided in the present application. The present application also provides a projection system, which includes the light-emitting device 1. The light-emitting device 1 is the light-emitting device 1 provided in any one of the above embodiments, and has corresponding technical features and technical effects, which will not be repeated here.

[0090] In summary, the excitation light emitted by the light source 11 is transmitted to the spectroscopic element 13 set in the middle of the prism 12 through the light incident surface of the prism 12. The spectroscopic element 13 reflects at least part of the excitation light to the wavelength conversion device 14. The wavelength conversion device 14 absorbs the excitation light and generates a stimulated light propagating toward the prism 12. The angular distribution of the excitation light does not change when propagating in the prism 12, which can reduce the area of ​​the spectroscopic element 13, thereby reducing the distance that the stimulated light enters the subsequent optical system, reducing the dilution of the expansion amount, and improving the efficiency of the light source.

[0091] The above are only implementation methods of the present application, and are not intended to limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A light emitting device, characterized in that: The light emitting device comprises: A light source, for emitting excitation light; A prism assembly, the prism assembly comprising a prism, the prism comprising a light incident surface, a functional surface opposite to the light incident surface, and a beam splitter element disposed between the light incident surface and the functional surface, the light source being disposed on one side of the light incident surface; A wavelength conversion device, used for absorbing the excitation light and emitting the excited light propagating toward the prism under excitation; The prism assembly further comprises an optical processing element disposed on the functional surface, and the beam splitting element is located between the optical processing element and the light incident surface; Among them, the excitation light of the light source is transmitted to the spectroscopic element arranged in the prism through the light incident surface of the prism, and the spectroscopic element is used to reflect part of the excitation light to the wavelength conversion device, and transmit the remaining part of the excitation light to form bypass light and irradiate the optical processing element; the bypass light is processed by the optical processing element and then returned to the spectroscopic element, and is reflected by the spectroscopic element to form the second output light.

2. The light emitting device according to claim 1, characterized in that: The light emitting device further comprises a light homogenizing device; The light homogenizing device is arranged between the light source and the prism, and the light emitting surface of the light homogenizing device is close to the light incident surface of the prism; the light incident surface area of ​​the prism matches the size of the light spot emitted by the light homogenizing device.

3. The light emitting device according to claim 1, characterized in that: The beam splitter element is a polarization beam splitter element, and the polarization beam splitter element is used to reflect the excitation light in the first polarization state to the wavelength conversion device, and transmit the excitation light in the second polarization state to form the bypass light and irradiate it to the optical processing element; The optical processing element includes a reflector and a quarter wave plate, wherein the quarter wave plate is located between the reflector and the polarization splitter element, and the quarter wave plate and the reflector cooperate to change the polarization direction of the bypass light so that the bypass light with the changed polarization direction can be reflected by the polarization splitter element to form a second output light.

4. The light emitting device according to claim 1, characterized in that: The optical processing element includes a reflective mirror.

5. The light emitting device according to claim 1, characterized in that: The prism includes four side surfaces connecting the light incident surface and the functional surface, the four side surfaces are respectively perpendicular to the light incident surface and the functional surface, and at least one group of opposite side surfaces are parallel to each other.

6. A projection system, characterized in that: The projection system comprises the light emitting device according to any one of claims 1-5.

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