Optical system and projection device

Abstract

The utility model discloses an optical system and a projection device, and relates to the technical field of photoelectricity. The optical system comprises a light source assembly, a wavelength conversion device, a dichroic element and a light combination assembly, through a first light combination element and a second light combination element, the angles of all kinds of light entering a dodging element are symmetrical, and the dodging effect is improved; a light guide area of the wavelength conversion device is a transmission area, light paths of first light (emitted as illumination light) and excited light emitted from the wavelength conversion device are different, the first light directly enters the light combination assembly, the excited light enters the dichroic element and is reflected to the light combination assembly through the dichroic element, and the dichroic element transmits the first laser and reflects the excited light; therefore, the residual first laser in the excited light can be partially transmitted by the dichroic element, and the residual first laser in the excited light can be reduced.

Description

Technical Field

[0001] The present invention relates to the field of optoelectronic technology, and in particular to an optical system and a projection device. Background Art

[0002] In the field of projection display, traditional light bulbs are increasingly not used due to their own defects, while new light sources such as LED, fluorescent and laser have shown excellent characteristics in terms of brightness, color, life, energy consumption, etc., and have gradually become the mainstream of light sources for projection display. As a light source, the laser has the advantages of high brightness and high light efficiency, and the optical extension of the laser is usually relatively small, the spot formed on the optical element is also small, and the energy is relatively concentrated. In order to achieve good viewing quality, existing projection equipment uses blue laser to excite the fluorescence generated by the fluorescent wheel. However, there is a lot of residual blue light in the fluorescence, resulting in poor color points of the fluorescence. In order to obtain a better color gamut, it is generally necessary to add a color filter wheel to filter the fluorescence spectrum, which leads to an increase in volume and higher cost. Summary of the invention

[0003] In view of this, the present invention provides an optical system and a projection device to reduce residual excitation light in stimulated light.

[0004] In a first aspect, the present invention provides an optical system, comprising:

[0005] The light source assembly includes a first laser light source for emitting a first laser and a second light source for emitting a red primary color light;

[0006] The wavelength conversion device comprises a wavelength conversion area and a light guiding area, wherein the wavelength conversion area is used to generate a converted light under the irradiation of a first laser, and the light guiding area is a transmission area, which is used to transmit the first laser to form a first light, and then the first light is guided and emitted through a light combining component; the converted light is yellow fluorescence or green fluorescence;

[0007] A dichroic element, used for transmitting the first laser light and reflecting the stimulated light;

[0008] A light combining component, used for guiding the converted light, the red primary light and the first light to be incident on the light processing device from the same direction;

[0009] The light combining component includes a first light combining element and a second light combining element, wherein the first light combining element is used to transmit the red primary light and reflect the converted light; the second light combining element is used to reflect the first light so that the angle at which each light enters the light homogenizing element is symmetrical.

[0010] In a possible implementation, the beam reducing lens group is located between the light source assembly and the light splitting assembly, and is used to compress the light spot of the first laser;

[0011] A diffusion element or a homogenizing element, located between the light source assembly and the light splitting assembly, and used to homogenize the light spot of the first laser;

[0012] The first laser light processed by the beam reducing lens group and the diffusion element or the homogenization element all passes through the first area and is incident on the wavelength conversion device.

[0013] In a possible implementation, a collimating lens group is located between the wavelength conversion device and the light source assembly, and is used to collimate the converted light emitted from the wavelength conversion area, and the main light of the first laser emitted from the first laser light source does not coincide with the optical axis of the collimating lens group.

[0014] In one possible implementation, the focusing lens group is located between the light combining component and the light processing device, and is used to focus the light emitted by the light combining component into the light homogenizing element, so that more than 90% of the light emitted by the light combining component enters the light homogenizing element after passing through the focusing lens group and the light processing device.

[0015] In a possible implementation manner, a diffusion element is provided in the second zone.

[0016] In one possible implementation, the number of wavelength conversion zones and light guiding zones is n, the rotation speed of the wavelength conversion device is m rpm, n×m=q, where q is the screen refresh rate in HZ, n is greater than or equal to 1, and m is greater than 0.

[0017] In a possible implementation, the wavelength conversion device and the light processing device are integrated into one device.

[0018] In one possible implementation, the light source system includes a light processing device for processing the converted light and the first light and providing them to the light homogenizing element, the light processing device includes a first zone and a second zone, the first zone is used to pass the converted light, and the second zone is used to pass the first light, wherein the first zone includes a filter layer, the filter layer is used to transmit the converted light and at least reflect the light in the wavelength band where the first laser is located, so that the optical path of the first laser reflected by the filter layer is different from that of the first light passing through the second zone.

[0019] In a second aspect, the present invention provides a projection device, comprising the optical system described in the first aspect.

[0020] The optical system provided by the present invention uses a first light combining element and a second light combining element so that the angles at which each light enters the light homogenizing element are symmetrical, thereby improving the light homogenizing effect; the light guiding area of ​​the wavelength conversion device is a transmission area, and the light paths of the first light (emitted as illumination light) and the converted light after being emitted from the wavelength conversion device are different. The first light directly enters the light combining component, and the converted light enters the dichroic element and is reflected to the light combining component by the dichroic element. The dichroic element transmits the first laser and reflects the converted light; therefore, the first laser remaining in the converted light will be partially transmitted by the dichroic element, thereby reducing the residual first laser in the converted light. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A schematic diagram of functional modules of a projection device provided by an embodiment of the present invention;

[0022] Figure 2 A schematic diagram of the structure of a projection device provided by an embodiment of the present invention;

[0023] Figure 3 A schematic diagram of the structure of an optical system provided by an embodiment of the present invention;

[0024] Figure 4 A schematic diagram of the structure of an optical system provided by an embodiment of the present invention;

[0025] Figure 5 A schematic diagram of the structure of an optical system provided by an embodiment of the present invention;

[0026] Figure 6 A schematic diagram of the structure of an optical system provided by an embodiment of the present invention;

[0027] Figure 7 A schematic diagram of light combination of a first laser light source provided in an embodiment of the present invention;

[0028] Figure 8 A schematic diagram of light combination of a first laser light source provided in an embodiment of the present invention;

[0029] Fig. 9 A schematic diagram of the structure of a light combining component provided by an embodiment of the present invention;

[0030] Fig.10 A schematic diagram of the structure of an optical system provided by an embodiment of the present invention;

[0031] Fig.11 A schematic diagram of the structure of a wavelength conversion device provided by an embodiment of the present invention;

[0032] Fig.12 A schematic diagram of the structure of a wavelength conversion device provided by an embodiment of the present invention;

[0033] Fig.13 A schematic diagram of the structure of a wavelength conversion device provided by an embodiment of the present invention;

[0034] Fig.14 A schematic diagram of the structure of a wavelength conversion device provided by an embodiment of the present invention;

[0035] Fig.15 A schematic structural diagram of an optical system provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0036] In order to make those skilled in the art better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. Although the disclosure in the present invention is introduced according to one or several exemplary examples, it should be understood that each aspect of these disclosures can also constitute a complete technical solution separately. In the absence of conflict, the following embodiments and the features in the embodiments can be combined with each other.

[0037] In the present invention, in order to facilitate the clear description of the technical solutions of the embodiments of the present invention, the words "first", "second" and the like are used to distinguish the same items or similar items with basically the same functions and effects. Those skilled in the art can understand that the words "first", "second" and the like do not limit the quantity and execution order, and are only used to illustrate and distinguish the objects to be described. There is no order distinction, nor does it represent a special limitation on the number of devices or messages in the embodiments of the present invention, and cannot constitute any limitation on the embodiments of the present invention. "Multiple" means two or more, and similar words such as "include" or "comprising" mean that the element or object appearing before the word covers the elements or objects listed after the word and their equivalents, but does not exclude other elements or objects.

[0038] In order to fully understand the present invention, a detailed description will be provided below to illustrate the technical solution of the present invention. Preferred embodiments of the present invention are described in detail below, but in addition to these detailed descriptions, the present invention may also have other embodiments.

[0039] Figure 1 Schematic diagram of the functional modules of a projection device provided by an embodiment of the present invention. Figure 1 As shown, the projection device includes an image processor 110 and a projection optical engine 120. Among them:

[0040] The image processor 110 may be a microcontroller, a dedicated image processing chip, etc. The microcontroller may be an ARM chip, a microcontroller unit (MCU), etc. The dedicated image processing chip may be an image signal processor (ISP), a graphics processing unit (GPU), an embedded neural network processor (NPU), etc. The image processor 110 may be used for video decoding, image quality processing, etc.

[0041] The projection optical machine 120 may include a driving chip, a display chip, and a light source. The light source may include a laser light source, an LED light source, a fluorescent light source, etc. The display chip may be a digital micromirror device (DMD), a liquid crystal display (LCD), a liquid crystal on silicon (LCOS), etc., which is used to modulate the light source to generate image light. The driving chip corresponds to the display chip, for example, the digital micromirror device may be driven by a digital light processing element (DLP). The projection optical machine 120 is used to project the image to be projected into a projection screen.

[0042] In some embodiments, the projection device further includes a central controller 130 having one or more processing cores, which may be a CPU, ARM, MCU or other controller. The central controller 130 is the control center of the projection device, and uses various interfaces and lines to connect various parts of the entire projection device, and can run or execute software programs and / or operating systems stored in the storage module 140, and call data stored in the storage module 140. Optionally, the image processor 110 and the central controller 130 may be integrated into one processor.

[0043] In some embodiments, the projection device further includes components such as a storage module 140 of one or more computer-readable storage media, an input module 150, and a communication module 160. Those skilled in the art will appreciate that Figure 1 The structure of the projection device shown in the figure does not constitute a limitation on the projection device, and may include more or fewer components than shown in the figure, or combine certain components, or arrange the components differently.

[0044] The storage module 140 can be used to store software programs and operating systems. The central controller 130 executes various functional applications and data processing by running the software programs and operating systems stored in the storage module 140. The storage module 140 may mainly include a program storage area and a data storage area, wherein the program storage area may store an operating system, an application required for at least one function (such as a sound playback function, an image playback function, etc.), etc.; the data storage area may store data created according to the use of the projection device, etc. In addition, the storage module 140 may include a high-speed random access memory, and may also include a non-volatile memory, such as at least one disk storage device, a flash memory device, or other volatile solid-state storage devices. Accordingly, the storage module 140 may also include a memory controller to provide the central controller 130 with access to the storage module 140.

[0045] The projection device may further include an input module 150, which may be used to receive input digital or character information and generate remote controller, keyboard, mouse, joystick, optical or trackball signal input related to user settings and function control.

[0046] The projection device may further include a communication module 160. In some embodiments, the communication module 160 may include a wireless module. The projection device may perform short-range wireless transmission through the wireless module of the communication module 160, thereby providing the user with wireless broadband Internet access. For example, the communication module 160 may be used to help the user access streaming media, etc.

[0047] Figure 2 FIG. 1 is a schematic diagram of a structure of a projection device provided by an embodiment of the present invention. Figure 2 As shown, the projection device includes a light source device 210, a light homogenizing element 220, an illumination system 230, and an imaging system 240. The illumination light generated by the light source device 210 is homogenized by the light homogenizing element 220, and the illumination system 230 images the light spot emitted by the light homogenizing element 220 on a display chip (not shown in the figure). The display chip modulates the incident illumination light into image light and irradiates it into the imaging system 240, and finally images the image light onto a projection plane such as a screen to form a projection picture.

[0048] In addition, the projection device may further include a light source control module (not shown in the figure), which may control the operation of one or more light sources in the light source device 210 so that the light source device 210 emits light of a specified wavelength band required for generating an image. Further, the light source device 210, the light homogenizing element 220, the illumination system 230 and the imaging system 240 may all be included in the projection optical machine 120 (see Figure 1 )middle.

[0049] The light source device 210 may include one or more light sources. The light source may be a laser light source, an LED light source, or a fluorescent light source, etc. Further, the light source may be a single light emitting element or a light emitting element array, and the light emitting element array may include light emitting elements of different colors. For example, the light source may be an LD light source or an LED light source that generates blue light, green light, or red light, etc., or the light source may be a multicolor laser, that is, a light emitting element array containing multiple lasers, such as the light source may contain a blue laser and a red laser, or contain a blue laser and a green laser, or contain a blue laser, a red laser, and a green laser at the same time.

[0050] The light homogenizing element 220 is used to homogenize the illumination light generated by the light source device 210. Specifically, the light homogenizing element 220 includes an incident surface and an exit surface, and the light homogenizing element 220 is used to homogenize the illumination light incident from its incident surface. For example, the light homogenizing element 220 can be a light rod, a compound eye, or the like.

[0051] The illumination system 230 is a part from the light homogenizing element to the display chip, and is used to image the light spot emitted by the light homogenizing element 220 onto the display chip. By way of example, the illumination system 230 may include one or more lenses.

[0052] The imaging system 240 is used to image the image light onto a projection plane such as a screen to form a projection image. The imaging system 240 is generally a lens system, such as a projection lens.

[0053] Figure 3-6 Schematic diagram of the structure of the optical system provided by the embodiment of the present invention. Figure 3-6 As shown, the optical system includes a light source assembly 100 and a wavelength conversion device 200. The optical system can be Figure 2 The light source device shown. The light source assembly 100 is used to emit light source light, which may include only laser light, only LED light, or both laser and LED light. The wavelength conversion device 200 is used to generate stimulated light (such as fluorescence) under the irradiation of at least part of the light source light. In the embodiment of the present invention, the illumination light emitted by the optical system includes at least stimulated light and emitted laser light. By mixing the laser and stimulated light, the speckle and color edge problems in the laser solution can be improved. In some other embodiments, the illumination light emitted by the optical system may also include LED light.

[0054] The light source assembly 100 includes a first laser light source 101, and the first laser light source 101 is used to emit a first laser. For example, the first laser light source can be a short-wave visible light source with a wavelength range between 440nm-480nm. Preferably, the first laser light source 101 is a blue laser light source. It should be understood that the first laser light source 101 can also be short-wave invisible light, such as UV light. Further, the first laser light source 101 can include one or more laser modules. The number of light-emitting chips in each laser module is not limited. It can be a single light-emitting chip or a light-emitting chip array. For example, a blue laser module can be 1 column of light spots or 2 columns of light spots. The light can be combined by splicing with reflectors or by polarization. It should be noted that Figure 3-6 In the figure, the solid arrows represent the light in the wavelength band emitted by the first light source 101, the dotted arrows represent the light in the wavelength band emitted by the converted light, and the dashed arrows represent the light in the wavelength band emitted by the second light source 102.

[0055] For example, Figure 7-8As shown, the first laser light source 101 includes a first sub-laser module 1011, a second sub-laser module 1012 and a light combining module 1013, wherein the first sub-laser module 1011 is used to emit a first sub-laser having a second color, and the second sub-laser module 1012 is used to emit a second sub-laser having a second color. The wavelength bands of the first sub-laser and the second sub-laser may be the same or different. For example, the first sub-laser module 1011 and the second sub-laser module 1012 are both blue laser modules, the main wavelength of the first sub-laser module 1011 is 455nm, and the main wavelength of the second sub-laser module 1012 is 465nm. The use of two different wavelengths of blue light further reduces the speckle effect.

[0056] In some embodiments, the light combining module 1013 includes one or more reflectors for guiding the first sub-laser and the second sub-laser to emit from the same direction to form a first laser, so that the spot size of the first laser is larger than the spot size of either the first sub-laser or the second sub-laser and is smaller than or equal to the sum of the spot sizes of the first sub-laser and the second sub-laser. Figure 7 In some other embodiments, the light combining module 1013 includes a polarization light combining element, which is used to combine the first sub-laser and the second sub-laser into a first laser after polarization light combining, so that the spot size of the first laser is equal to the spot size of the larger one of the first sub-laser and the second sub-laser, such as Figure 8 Optionally, when the polarization states of the first sub-laser and the second sub-laser are the same, a wave plate may be used to change the polarization state of one of them, thereby achieving polarization light combination.

[0057] The wavelength conversion device 200 includes a wavelength conversion area, and the wavelength conversion area is used to generate a converted light under the irradiation of a first laser. In this case, the first laser is called an excitation light. The wavelength conversion area may include one or more color conversion areas, such as a green fluorescent area and / or a red fluorescent area, and may also include an orange or yellow fluorescent area. For example, the wavelength conversion area includes a first color conversion area, and the first color conversion area is used to generate a first sub-converted light with a first color under the irradiation of the first laser. Preferably, the first sub-converted light accounts for a luminous flux of greater than or equal to 20% and less than or equal to 90% in the white field, such as 20%, 30%, 50%, 70% or 90%, and preferably greater than or equal to 50% and less than or equal to 90%, thereby improving the speckle and color edge problems in the laser solution and taking into account the high efficiency and color of the laser. Optionally, the first sub-converted light accounts for a luminous flux of greater than or equal to 70% in the white field. In this case, the light of the first color in the illumination light emitted by the optical system may only include the first sub-converted light, and there is no need to add other light sources that generate the first color, thereby reducing costs. Furthermore, the first color is preferably green, which can improve the speckle and color edge effects of the white field more significantly than other colors.

[0058] The illumination light emitted by the optical system includes the first sub-excitation light. The emitted laser light included in the illumination light may be emitted by other laser light sources (laser light sources other than the first laser light source 101), or may be obtained by changing the optical path of the first laser, or may include both the light obtained by changing the optical path of the first laser and the light emitted by other laser light sources.

[0059] See also Figure 3 In some embodiments, the light source assembly further includes a second light source 102. In this embodiment, the second light source 102 is a laser light source for emitting a second laser. The second laser and the stimulated laser emitted by the wavelength conversion device 200 are combined to form the illumination light emitted by the entire optical system. The second light source 102 can be packaged into one with the first laser light source 101. For example, the light source assembly 100 can be obtained by packaging an LD light emitting chip array, such as a row of blue laser LD light emitting chips, a row of green laser LD light emitting chips, and one or two rows of red laser LD light emitting chips. The packaged light source has a compact structure and can reduce the volume of the projection device.

[0060] In some other embodiments, the wavelength conversion device 200 also includes a light transmission area, which is used to transmit the first laser emitted by the first laser light source 101 to form a first light, the first light and the stimulated light, or the first light and the second laser and the stimulated light to synthesize the illumination light emitted by the entire optical system.

[0061] See also Figure 4-5 The wavelength conversion device 200 further includes a light guiding region, which is used to guide the propagation direction of the first laser emitted by the first laser light source 101 to form the first light. The light guiding region can be a transmission region (such as Figure 4 as shown) or reflection area (as Figure 5 In this embodiment, the optical system further includes a light combining component 300, which is used to guide the converted laser light and the emitted laser light to be emitted from the same direction, thereby forming illumination light. Further, the optical system further includes a light splitting component 400, which is used to guide the first laser light to be incident on the wavelength conversion device 200, and to guide one of the converted laser light and the first light to be incident on the light combining component 300.

[0062] like Figure 4As shown, the beam splitter component 400, such as a beam splitter, is used to transmit the first laser emitted by the first laser light source 101 to the wavelength conversion device 200. At the first moment, the wavelength conversion area of ​​the wavelength conversion device 200 generates a converted light under the irradiation of the first laser. The converted light is reflected back to the beam splitter component 400 through the wavelength conversion device 200, and is reflected to the light combining component 300 through the beam splitter component 400, and finally guided out through the light combining component 300. At the second moment, the light guiding area of ​​the wavelength conversion device 200, such as the transmission area, transmits the first laser to form the first light, and then the first light is guided out through the light combining component 300. In this embodiment, the beam splitter component 400 can be a dichroic element that transmits the first laser and reflects the converted light. If the first laser is a blue laser and the converted light is a green fluorescent light, the beam splitter component 400 can be a dichroic element that transmits blue and reflects green. Optionally, after the light guiding area of ​​the wavelength conversion device 200 transmits the first laser to form the first light, the first light may be incident on the light splitting component 400 again after the propagation direction is changed by a reflective element or other element, and then transmitted to the light combining component 300 through the light splitting component 400. Furthermore, the second light emitted by the second light source 102 may also be guided out through the light combining component 300.

[0063] like Figure 5 As shown, the beam splitter component 400, such as a beam splitter, is used to transmit the first laser emitted by the first laser light source 101 to the wavelength conversion device 200. At a first moment, the wavelength conversion area of ​​the wavelength conversion device 200 generates a stimulated light under the irradiation of the first laser. The stimulated light is reflected back to the beam splitter component 400 through the wavelength conversion device 200, and is reflected to the light combining component 300 through the beam splitter component 400, and finally guided out through the light combining component 300. At a second moment, the light guiding area of ​​the wavelength conversion device 200, such as the reflection area, reflects the first laser to form a first light, and then the first light is guided out through the light combining component 300. In this embodiment, the beam splitter component 400 can be a beam splitter including a first area A and a second area B, such as Fig. 9As shown, the first region A transmits the light in the wavelength band of the first laser, and the second region B reflects the light in the wavelength band of the first light and the stimulated light, wherein the first region A can be a through hole or a coating region on the reflector, and the first laser emitted by the first laser light source 101 is transmitted to the wavelength conversion device 200 through the first region A, and the stimulated light and the first light reflected by the wavelength conversion device 200 are reflected to the light combining component 300 through the second region B. Preferably, the first region A allows the light in the wavelength band of the first laser to pass through and reflects the light in the wavelength band of the stimulated light, such as the first region A is coated with a blue-transmitting and green-reflecting film layer, and the second region B is coated with a total reflection film, so that the blue light can both penetrate and reflect on the same element (i.e., the light splitting component 400), realizing the function of combining blue light with fluorescence, and reducing the damage of the reflected fluorescence, and filtering out the first laser that is not excited in the fluorescence, such as blue light, to reduce the problem of residual blue light. Furthermore, the first region A may be disposed away from the center of the beam splitter, and the sizes of the first region A and the second region B are not particularly limited. The area of ​​the first region A may be larger than the second region B, or smaller than or equal to the second region B.

[0064] In some embodiments, the emitted laser may include only the first light, and the first laser may be changed in propagation direction by the light guiding region of the wavelength conversion device 200 to form the first light, such as Figure 4-5 As shown, the first light may be formed without passing through the light guiding area of ​​the wavelength conversion device 200, such as Figure 6 In some other embodiments, continue to refer to Figure 4-5 The light source assembly 100 further includes a second light source 102, which is used to emit a second light. The light combining assembly 300 is used to guide the first light, the second light, and the stimulated light to be emitted from the same direction. The second light source 102 can be a laser light source, an LED light source, or other types of light sources, or a mixed light source of a laser light source and an LED light source. When the second light source 102 includes a laser light source, such as a red laser light source, the emitted laser includes the laser light emitted by the second light source 102 and the first light. When the second light source 102 includes an LED light source, the illumination light emitted by the optical system includes three types of light: laser light, LED light, and fluorescent light.

[0065] Further, the number of wavelength conversion areas and light guide areas included in the wavelength conversion device 200 is n. Assuming that the rotation speed of the wavelength conversion device 200 is m rpm, then n×m=q, where q is the picture refresh rate, in units of HZ, n is greater than or equal to 1, and m is greater than 0. For example, if the rotation speed of the wavelength conversion device 200 is 120 rpm, then n=1, and the picture refresh rate of the projection device is 120HZ. If n=2, the picture refresh rate of the projection device is 240HZ. When the rotation speed of the wavelength conversion device 200 remains unchanged, different image quality requirements can be met by setting the number of wavelength conversion areas and light guide areas. It should be understood that in some other embodiments, the wavelength conversion device 200 may only include the wavelength conversion area but not the light guide area. If the wavelength conversion area includes multiple color conversion areas, the number of each color conversion area also satisfies the above relationship, which will not be repeated here.

[0066] In the above embodiment, the first laser light source 101 may provide light sources for the first light and the stimulated light at the same time. In the prior art, the current of the first laser light source 101 within a frame display cycle is uniformly controlled. For example, a frame display cycle includes a first time period and a second time period, wherein the first time period is used to emit the stimulated light, and the second time period is used to emit the first light. Then, within a frame display cycle, if the current of the first laser light source 101 is adjusted, the current of the first laser light source 101 in the first time period and the second time period will change at the same time, that is, the current of the first laser light source 101 in the first time period and the second time period is always the same, making it difficult to balance the color gamut, color point and brightness. In the embodiment of the present invention, the optical system may further include a control unit 500, such as Fig.10 As shown, the control unit 500 is connected to the first laser light source 101, and the control unit 500 is used to separately control the current of the first laser light source 101 in the first time period and the second time period, that is, the control unit 500 can set the current of the first laser light source 101 in the first time period and the second time period respectively. For example, in a certain frame display cycle, the control unit 500 can only increase or decrease the current of the first laser light source 101 in the first time period, or only increase or decrease the current of the first laser light source 101 in the second time period, or while increasing the current of the first laser light source 101 in the first time period, reduce the current of the first laser light source 101 in the second time period, etc. That is, the current of the first laser light source 101 in the first time period and the second time period can be different, and the brightness can be made higher while ensuring a certain white balance condition. It should be noted that Fig.10 In the figure, the solid arrows represent the light in the wavelength band emitted by the first light source 101, the dotted arrows represent the light in the wavelength band emitted by the converted light, and the dashed arrows represent the light in the wavelength band emitted by the second light source 102.

[0067] Specifically, the control unit 500 can be used to adjust the current of the first laser light source 101 in the first time period and the second time period according to the adjustment signal. The adjustment signal can be a signal for the projection device to automatically switch the display mode according to the display requirements, or an adjustment signal received by the projection device, such as an adjustment instruction sent by the user to the projection device according to his own needs. The adjustment instruction can be a display mode switching instruction sent by the user or a brightness adjustment instruction sent by the user.

[0068] In some embodiments, the wavelength conversion region of the wavelength conversion device 200 includes a first color conversion region, the first time period includes a first sub-time period for emitting a first sub-excited light, and the control unit 500 is used to increase the current of the first laser light source in the first sub-time period, or reduce the current of the first laser light source in the second time period, or while increasing the current of the first laser light source in the first sub-time period, reduce the current of the first laser light source in the second time period, so as to increase the proportion of the first sub-excited light, such as the first sub-excited light is green fluorescence or yellow fluorescence, etc., containing a green primary color spectrum, that is, the optical system emits green primary color light in the first sub-time period. Correspondingly, when the adjustment signal indicates that the vertical coordinate of the white field becomes low, the current of the first laser light source in the first sub-time period is reduced and / or the current of the first laser light source in the second time period is increased, so as to reduce the proportion of the first sub-excited light. It should be noted that the adjustment signal indicating that the vertical coordinate of the white field becomes higher or lower may mean that the vertical coordinate of the white field corresponding to the display mode after switching becomes higher or lower than that of the display mode before switching, or it may mean that the vertical coordinate of the white field corresponding to the adjustment parameter in the adjustment instruction becomes higher or lower, or the adjustment signal directly indicates that the vertical coordinate of the white field becomes higher or lower.

[0069] In some other embodiments, the wavelength conversion region of the wavelength conversion device 200 includes a second color conversion region, the second color conversion region is used to generate a second sub-excited light under the irradiation of the first laser, the first time period includes a second sub-time period for emitting the second sub-excited light, and the control unit 500 is used to increase the current of the first laser light source in the second sub-time period, or reduce the current of the first laser light source in the second time period, or increase the current of the first laser light source in the second sub-time period while reducing the current of the first laser light source in the second time period, so as to increase the proportion of the second sub-excited light, such as the second sub-excited light is red fluorescence or yellow fluorescence, etc., which contains a red primary light spectrum, that is, the optical system emits red primary light in the second sub-time period. Correspondingly, when the adjustment signal indicates that the horizontal coordinate of the white field becomes low, the current of the first laser light source in the second sub-time period is reduced and / or the current of the first laser light source in the second time period is increased, and the proportion of the second sub-excited light is reduced. It should be noted that the adjustment signal indicating that the horizontal coordinate of the white field becomes higher or lower may mean that the horizontal coordinate of the white field corresponding to the display mode after switching becomes higher or lower than that of the display mode before switching, or it may mean that the horizontal coordinate of the white field corresponding to the adjustment parameter in the adjustment instruction becomes higher or lower, or the adjustment signal directly indicates that the horizontal coordinate of the white field becomes higher or lower.

[0070] The illumination light emitted by the optical system is usually composed of three primary colors of light that can be synthesized into white light, such as red primary light, green primary light and blue primary light. If the wavelength conversion area of ​​the wavelength conversion device 200 only includes the first color conversion area or the second color conversion area, that is, the converted light only contains fluorescence of one color, then a frame display cycle includes not only the first time period and the second time period, but also the third time period. The third time period is used to emit the third light, and the third light can be one of the second lights emitted by the second light source 102. Then, in the first time period and the second time period, the first laser light source 101 is turned on, and the optical system emits the converted light and the first light respectively. In the third time period, the second light source 102 is turned on, and the optical system emits the third light. The converted light, the first light and the third light can be synthesized into white light. If the second light emitted by the second light source 102 contains light of the same color as the converted light, then in the first time period, the light source emitting the same color in the second light source 102 is also turned on. For example, Fig. 9As shown, the wavelength conversion area of ​​the wavelength conversion device 200 may only include the first color conversion area that generates green fluorescence, the light guiding area is a reflection area, the first laser light source 101 is used to generate blue laser, the second light source 102 is used to generate red laser, and a frame display cycle includes the third period, the first period, and the second period in sequence. The second light source 102 is lit in the third period to emit red primary color light, and the first laser light source 101 is lit in the first period and the second period to emit green primary color light and blue primary color light respectively. It should be understood that the wavelength conversion area of ​​the wavelength conversion device 200 may also include the first color conversion area and the second color conversion area at the same time. In this case, the optical system may not include the second light source 102, and a frame display cycle may only include the first period and the second period, and the first period includes the first sub-period and the second sub-period.

[0071] Continue reading Fig.10 The optical system may further include a light processing device 600 for processing the light emitted by the light combining component 300 and providing it to a light homogenizing element (not shown in the figure). The light processing device 600 includes a first zone and a second zone. The first zone is used to pass the stimulated light, and the second zone is used to pass the emitted laser. For example, the first zone is used to transmit the stimulated light, and the second zone is used to transmit and diffuse the emitted laser. That is, the first zone can be a high-transmittance flat plate element, and the second zone is provided with a diffusion element. It should be understood that when the converted light includes multiple colors of fluorescence, the first area may include one or more different sub-areas for processing different fluorescence. When the emitted laser includes one or more lasers, the second area may also include one or more different sub-areas for processing different lasers. For example, if the emitted laser includes the first light and the third light, the second area may be a complete area or may include two different sub-areas, one for processing the first light and the other for processing the third light. The diffusion angles of the two sub-areas may also be set according to the characteristics of the first light and the third light, that is, the diffusion angles of the two sub-areas may be different. For example, if the first light is a blue laser, the converted light is a green fluorescence, and the third light is a red laser, the diffusion angle of the sub-area for processing the third light may be greater than the diffusion angle of the sub-area for processing the first light, further reducing the speckle effect. Furthermore, the first area may also include a diffusion element to diffuse the light. For example, if the second light emitted by the second light source 102 includes a green laser, the first area is also used to pass the green laser. If the first area is only used to pass the green fluorescence, the first area may not need to be provided with a diffusion element, such as a diffusion sheet. It should be noted that the first area and / or the second area of ​​the light processing device 600 may be a reflective area.

[0072] Optionally, a filter layer may be further provided in the first area of ​​the light processing device 600. For example, the first area may be a filter (such as a dichroic film coated on a transparent substrate), or one side may be coated with a dichroic film and the other side may be a diffuser or a double-layer structure in which a diffuser and a filter are superimposed. The filter layer is used to transmit the converted light and at least reflect the light in the wavelength band where the first laser is located. For example, the converted light is green fluorescence and the first laser is blue laser, then the filter layer transmits the green fluorescence and reflects the blue laser, that is, the filter layer can filter out the unexcited blue laser in the green fluorescence. At the same time, the first light (that is, the blue laser) is transmitted through the second area of ​​the light processing device 600, so that the optical path of the first laser reflected by the filter layer is different from the optical path of the first light transmitted through the second area. Then, by setting the filter layer, the optical path of the unexcited first laser in the converted light can be separated from the optical path of the first light, thereby filtering out the residual first laser in the converted light and improving the color gamut. Furthermore, the filter layer in the first area can not only reflect the light in the wavelength band of the first laser, but also reflect the light in a preset wavelength band in the converted light, such as the light with a longer wavelength in the green fluorescence, to make the green color purer.

[0073] In some embodiments, the wavelength conversion device 200 and the light processing device 600 are integrated into one device. Figure 11-Figure 14 As shown, the wavelength conversion device and the light processing device are arranged circumferentially or radially, see Fig.11 The wavelength conversion device and the light processing device are arranged along the circumferential direction, the first color conversion area PW1 of the wavelength conversion device and the first area DW1 of the light processing device are arranged symmetrically, and the light guiding area W2 of the wavelength conversion device and the second area DW2 of the light processing device are arranged symmetrically. Figure 12-14 The wavelength conversion area and the light guiding area of ​​the wavelength conversion device are arranged along the circumferential direction, the wavelength conversion device and the light processing device are arranged along the radial direction, and the wavelength conversion area of ​​the wavelength conversion device may only include the first color conversion area PW1 (such as Figure 12-13 ), and may also include a first color conversion region PW1 and a second color conversion region PW3 (as shown in FIG. Fig.14 The optical processing device may include only the first area DW1 and the second area DW2 (as shown); Fig.12 As shown), at least one of the first area DW1 and the second area DW2 is used to process two kinds of light, and the light processing device may also include a first area DW1, a second area DW2 and a third area DW3 (as shown Figure 13-14 As shown), each zone is used to process one type of light. Figure 12-14 In the illustrated embodiment, the light processing device is located at the outer circle of the wavelength conversion device. It should be noted that the light processing device may also be located at the inner circle of the wavelength conversion device.

[0074] The following further describes the example in which the first laser light source 101 is a blue laser light source, the second light source 102 is a red laser light source, the wavelength conversion area of ​​the wavelength conversion device 200 is a green phosphor area, and the light guiding area is a reflection area.

[0075] like Fig.15 As shown, the blue laser emitted by the first laser light source 101 is transmitted to the wavelength conversion device 200 through the first area of ​​the beam splitter component 400. The green phosphor area and the reflection area of ​​the wavelength conversion device 200 are alternately located in the optical path of the blue laser. The green phosphor area generates green fluorescence under the irradiation of the blue laser. The green fluorescence is reflected back to the beam splitter component 400 through the wavelength conversion device 200, and is reflected to the light processing device 600 through the beam splitter component 400 and the light combining component 300 in turn, and is transmitted to the uniform light element 700 through the first area of ​​the light processing device 600; the reflection area reflects the first laser to form the first light, and the first light is reflected to the light processing device 600 through the second area of ​​the beam splitter component 400 and the light combining component 300 in turn, and is transmitted to the uniform light element 700 through the second area of ​​the light processing device 600. It should be noted that Fig.15 In the figure, the solid arrows represent the light in the wavelength band emitted by the first light source 101, the dotted arrows represent the light in the wavelength band emitted by the converted light, and the dashed arrows represent the light in the wavelength band emitted by the second light source 102.

[0076] In some embodiments, the light combining component 300 includes a first light combining element 301 and a second light combining element 302, wherein the first light combining element 301 is used to transmit the first light and reflect the stimulated light, and the second light combining element 302 is used to reflect the first light, so that the angles at which each light enters the light homogenizing element 700 are symmetrical, such as making the optical axes of the first light and the stimulated light coincide with the optical axis of the light homogenizing element 700, ensuring that the angles at which the first light and the stimulated light enter the light homogenizing element 700 are symmetrical, thereby improving the light homogenizing effect. Furthermore, the second light combining element 302 is also used to transmit the second light emitted by the second light source 102. In this embodiment, the first light combining element 301 may be a dichroic element that transmits red, blue and reflects green, and the second light combining element 302 may be a dichroic element that transmits red and reflects blue. The sizes of the first light combining element 301 and the second light combining element 302 may be the same or different.

[0077] Optionally, the optical system further includes a beam reduction lens group 103, which is located between the light source assembly 100 and the light splitting assembly 400. The beam reduction lens group 103 may include one or more lenses, which function to compress the light spot of the first laser. Further, the optical system further includes a diffusion element 104, which is located between the light source assembly 100 and the light splitting assembly 400, which functions to homogenize the light spot of the first laser, reduce the power density of the first laser irradiated to the wavelength conversion area, and the first laser processed by the beam reduction lens group 103 and the diffusion element 104 is incident on the wavelength conversion device 200 through the first area of ​​the light splitting assembly 400, thereby improving the light efficiency of the first laser. Among them, the diffusion element 104 can be located between the beam reduction lens group 103 and the light splitting assembly 400, or between the multiple lenses included in the beam reduction lens group 103. Compared with the diffusion element 104 being located between the light splitting assembly 400 and the wavelength conversion device 200, it can avoid the converted light from passing through the diffusion element, thereby reducing the loss of the converted light. It should be understood that the diffusion element 104 can also be replaced by a light homogenizing element such as a microlens array.

[0078] Optionally, the optical system further includes a collimating lens group 105, which is located between the wavelength conversion device 200 and the light source assembly 100, and is used to collimate the converted light emitted from the wavelength conversion region of the wavelength conversion device 200, and the main light of the first laser emitted from the first laser light source 101 does not coincide with the optical axis of the collimating lens group 105. The optical system may also include a relay lens 106 to improve the efficiency of the converted light entering the light homogenizing element 700 and reduce the spot size. The collimating lens group 105 may include one or more lenses. Furthermore, the first region of the light splitting component 400 is set away from the optical axis of the collimating lens group 105, so that the main light of the first laser emitted from the first laser light source 101 does not coincide with the optical axis of the collimating lens group 105, thereby separating the optical paths of the first laser incident to the wavelength conversion device 200 and the first light emitted from the wavelength conversion device 200, thereby improving the utilization rate of the first laser.

[0079] Optionally, the optical system also includes a filter element 107 and a driving element (not shown in the figure), and the filter element 107 is used to filter out the light of a preset wavelength band in the converted light to improve the purity of the converted light. The driving element is used to drive the filter element 107 so that the filter element 107 is located in the optical path of the converted light before the light combining component 300 or the filter element 107 is not in the optical path, so as to realize the function of switching between high and low color gamuts, and balance between brightness and color gamuts. When a high color gamut mode is required, the driving element drives the filter element 107 to move, rotate or swing to the area where the light passes, so that the converted light is purer; when a low color gamut mode is required, the driving element drives the filter element 107 to move, rotate or swing to a place where the light does not pass, and at this time the filter element 107 does not play an optical role.

[0080] In this embodiment, when the filter element 107 is located in the optical path of the first sub-excited light (such as green fluorescence), the green fluorescence is filtered by the filter element 107 and the filter layer in the first area of ​​the light processing device 600, which can greatly improve the purity of the green light and achieve the function of high color gamut. At this time, the color coordinates (Gx, Gy) of the first sub-excited light in the white field can meet the following conditions:

[0081] 0.23≤Gx≤0.29;0.65≤Gy≤0.74.

[0082] It should be understood that when the converted light includes sub-converted light of multiple colors, the filter element 107 may process only the sub-converted light of one color, or may process the sub-converted light of multiple colors, and in this case the filter element 107 may include one or more sub-areas.

[0083] Optionally, the optical system further includes a diffusion element 201, which is used to disperse and homogenize the light spot of the red laser emitted by the second light source 102. Further, the optical system further includes a shaping lens group 108, which is used to shape the red laser light.

[0084] Optionally, the optical system further includes a focusing lens group 109, which is located between the light combining component 300 and the light processing device 600, and is used to focus the light emitted by the light combining component 300 into the light homogenizing element 700, so that more than 90% of the light emitted by the light combining component 300 enters the light homogenizing element 700 after passing through the focusing lens group 109 and the light processing device 600, thereby reducing light loss. In this embodiment, the light homogenizing element 700 is preferably a light rod, and the size of the light emitting surface of the light processing device matches the size of the incident end face of the light rod, so that a large-sized light processing device is not required, thereby reducing the volume of the system.

[0085] Optionally, the optical system also includes a phase conversion element 202, which is located between the light combining component 300 and the light homogenizing element 700, preferably between the light combining component 300 and the light processing device 600, and is used to change the polarization state of the light emitted by the light combining component 300, so that there are at least two different polarization states in the light beam emitted at the same time, thereby further reducing the speckle effect.

[0086] It should be noted that the corresponding transmission function in the above embodiments can be changed to reflection, and the reflection function can be changed to transmission, which will not affect the functional realization of the overall optical path, and the embodiments of the present invention will not be described in detail.

[0087] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. An optical system, characterized in that: include: The light source assembly includes a first laser light source for emitting a first laser; and a second light source for emitting a red primary color light; The wavelength conversion device comprises a wavelength conversion area and a light guiding area, wherein the wavelength conversion area is used to generate converted light under the irradiation of the first laser, and the light guiding area is a transmission area, which is used to transmit the first laser to form a first light, and then the first light is guided and emitted through the light combining component; the converted light is yellow fluorescence or green fluorescence; A dichroic element, used for transmitting the first laser and reflecting the stimulated light; A light combining component, used for guiding the converted light, the red primary light and the first light to be incident on the light processing device from the same direction; The light combining component includes a first light combining element and a second light combining element, wherein the first light combining element is used to transmit the red primary light and reflect the converted light; the second light combining element is used to reflect the first light so that the angle at which each light enters the light homogenizing element is symmetrical.

2. An optical system according to claim 1, characterized in that: Also includes: A beam reducing lens group, located between the light source assembly and the light splitting assembly, and used for compressing the light spot of the first laser; A diffusion element or a homogenizing element, located between the light source component and the light splitting component, and used to homogenize the light spot of the first laser; The first laser light processed by the beam reducing lens group and the diffusion element or the homogenization element all passes through the first area and is incident on the wavelength conversion device.

3. An optical system according to claim 1, characterized in that: Also includes: The collimating lens group is located between the wavelength conversion device and the light source assembly, and is used to collimate the converted light emitted from the wavelength conversion area, and the main light of the first laser emitted from the first laser light source does not coincide with the optical axis of the collimating lens group.

4. An optical system according to claim 1, characterized in that: Also includes: A focusing lens group is located between the light combining component and the light processing device, and is used to focus the light emitted by the light combining component into the light homogenizing element, so that more than 90% of the light emitted by the light combining component enters the light homogenizing element after passing through the focusing lens group and the light processing device.

5. An optical system according to claim 1, characterized in that: The second zone is provided with a diffusion element.

6. An optical system according to claim 1, characterized in that: The number of the wavelength conversion areas and the light guiding areas is n, the rotation speed of the wavelength conversion device is m revolutions per second, n×m=q, wherein q is the picture refresh rate in HZ, n is greater than or equal to 1, and m is greater than 0.

7. An optical system according to claim 1, characterized in that: The wavelength conversion device and the light processing device are an integrated device.

8. An optical system according to claim 1, characterized in that: The optical system comprises: A light processing device, used for processing the converted light and the first light and providing them to a light homogenizing element, the light processing device comprising a first area and a second area, the first area being used to pass the converted light, the second area being used to pass the first light, wherein the first area comprises a filter layer, the filter layer being used to transmit the converted light and at least reflect light in a wavelength band where the first laser is located, so that the optical paths of the first laser reflected by the filter layer and the first light passing through the second area are different.

9. A projection device, characterized in that: An optical system comprising any one of claims 1-7.

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