WO2022017269A1

WO2022017269A1 - Projection system

Info

Publication number: WO2022017269A1
Application number: PCT/CN2021/106702
Authority: WO
Inventors: 龚晨晟; 赵鹏; 陈晨; 余新; 胡飞; 李屹
Original assignee: 深圳光峰科技股份有限公司
Priority date: 2020-07-21
Filing date: 2021-07-16
Publication date: 2022-01-27
Also published as: CN113960864A

Abstract

The present invention provides a projection system, comprising a laser light source, a beam splitting wheel, a fluorescent wheel, and an optical processing system. The beam splitting wheel comprises a partial beam splitting area and a guide area, the partial beam splitting area is used for splitting excitation light emitted by the laser light source into first excitation light and second excitation light, and the guide area is used for guiding the excitation light emitted by the laser light source to exit along a second optical path; the fluorescent wheel is used for converting the second excitation light from the second optical path into first excited light and converting the excitation light emitted by the laser light source into second excited light; and the optical processing system comprises a beam splitting member, a first spatial light modulator, and a second spatial light modulator. The first spatial light modulator and the second spatial light modulator of the projection system provided in the present invention can operate at full time, and the beam splitting of the excitation light by the partial beam splitting area reduces the power for displaying the excitation light, and improves the display bit depth of the projection system.

Description

Projection system

technical field

The present invention relates to the field of optical technology, in particular, to a projection system.

Background technique

Bit depth, also known as color depth, refers to the number of bits required to represent the grayscale information of a pixel in a grayscale image. The larger the bit depth, the more bits required, the smaller the difference between adjacent grayscale values, the less obvious the numerical sampling of analog information, and the more natural and smooth the transition of grayscale differences in the image.

However, the bit depth of the existing dual spatial light modulator display system cannot meet the increasing demands of projection display, and needs to be improved.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a projection system to solve the technical problem of increasing the bit depth of the projection system. The embodiments of the present invention achieve the above objects through the following technical solutions.

The invention provides a projection system including a laser light source, a light splitter wheel, a fluorescent wheel and a light processing system. A laser light source is used to emit excitation light. The beam splitter wheel includes a partial beam splitting area and a guide area. The partial beam splitting area is used to divide the excitation light emitted by the laser light source into a first excitation light and a second excitation light. The first excitation light exits along the first optical path, and the second excitation light exits along the second excitation light. The light path exits, and the guide area is used to guide the excitation light emitted by the laser light source to exit along the second optical path. The fluorescent wheel is used to convert the second excitation light from the second optical path into the first received laser light, and to convert the excitation light emitted from the laser light source into the second received laser light, and to convert the first received laser light into the third received laser light or The fourth received laser light or the mixed light of the third received laser light and the fourth received laser light. The light processing system includes a light splitting element, a first spatial light modulator and a second spatial light modulator, the light splitting element is used to guide the first excitation light from the first optical path to the first spatial light modulator, and the third received laser light or the second spatial light modulator. The fourth received laser light is directed to the first spatial light modulator or the second spatial light modulator, and the second received laser light is directed to the first spatial light modulator and the second spatial light modulator.

In one embodiment, the second received laser light and the first received laser light are of different colors, and the beam splitter is further used to divide the second received laser light into a third received laser light and a fourth received laser light, and guide the third received laser light to the first received laser light a spatial light modulator, and guides the fourth received laser light to the second spatial light modulator; the first spatial light modulator is used to modulate the first excitation light and the third received laser light, and the second spatial light modulator is used to modulate the fourth received laser light .

In one embodiment, the second received laser light and the first received laser light are of the same color, and the spectroscope is also used to divide the first received laser light and the second received laser light into a third received laser light and a fourth received laser light, and the third The received laser light is guided to the first spatial light modulator, and the fourth received laser light is guided to the second spatial light modulator; the first spatial light modulator is used to modulate the first excitation light and the third received laser light, and the second spatial light modulator uses for modulating the fourth received laser light.

In one embodiment, the projection system further includes a beam splitter wheel controller and a fluorescence wheel controller, the beam split wheel controller is used to control the rotation of the beam splitter wheel, the fluorescence wheel controller is used to control the rotation of the fluorescence wheel, and the beam splitter wheel and the fluorescence wheel are phase-synchronized .

In one embodiment, the projection system further includes a first modulation controller and a second modulation controller, the first modulation controller is used to control the first spatial light modulator, and the second modulation controller is used to control the second spatial light modulator , the first modulation controller, the second modulation controller, the light splitting wheel and the fluorescent wheel are phase-synchronized.

In one embodiment, the fluorescent wheel includes a concentrically arranged light conversion area and a light guide area, the light guide area surrounds the light conversion area, and the light conversion area is used to convert the second excitation light and the excitation light emitted from the laser light source into the first excitation light respectively. The first received laser light and the second received laser light, and the light guide area is used to guide both the first received laser light and the second received laser light to the light splitting element.

In one embodiment, the light conversion area includes a first light conversion area and a second light conversion area, the first light conversion area is used for converting the second excitation light into the first received laser light, and the second light conversion area is used for converting the second excitation light into the first received light. The excitation light emitted by the laser light source is converted into a second received laser light. The light guide area includes a first light guide area and a second light guide area. The first light guide area corresponds to the first light conversion area and is used to guide the first received laser light. To the light splitting element, the second light guide area corresponds to the second light conversion area for guiding the second received laser light to the light splitting element.

In an embodiment, the central angle corresponding to the first light conversion area is equal to the central angle corresponding to the partial light splitting area.

In one embodiment, the transmittance of the partial beam splitting area is equal to the reflectivity of the partial beam splitting area.

In one embodiment, the transmittance of the partial beam splitting area is greater than the reflectivity of the partial beam splitting area.

In one embodiment, the transmittance of the partial beam splitting area is less than the reflectivity of the partial beam splitting area.

In one embodiment, the projection system further includes a lens, and the light processing system further includes a light combining device, the light combining device is used for modulating the light emitted from the first spatial light modulator and modulating the output light from the second spatial light modulator. The light is combined and incident on the lens, which is used for projection.

In one embodiment, the projection system further includes a relay system, the relay system includes a first dichroic plate, a light homogenizer and a relay lens assembly, and the first dichroic plate is used for reflecting and transmitting the first excitation light The first received laser light and the second received laser light, and the light homogenizer is located between the first dichroic plate and the relay lens assembly, and the relay lens assembly is used to converge the first excitation light, the first received laser light and the second received laser light to the beam splitter.

In one embodiment, the projection system further includes a guide component, the guide component includes a second dichroic plate and a reflection component, the second dichroic plate and the reflection component are both located in the second optical path, and the second dichroic plate is used for The second excitation light and the excitation light emitted from the laser light source are guided to the fluorescent wheel, and the first received laser light and the second received laser light are guided to the reflection component, and the reflection component is used to guide the first received laser light and the second received laser light to the first received laser light and the second received laser light. A dichroic chip.

Compared with the prior art, the first spatial light modulator and the second spatial light modulator of the projection system provided by the present invention can work for full time, and the excitation light for display is reduced due to the splitting of the excitation light by part of the light splitting area. The power of the light increases the display bit depth of the projection system.

These and other aspects of the invention will be more clearly understood from the description of the following embodiments.

Description of drawings

In order to illustrate the technical solutions in this embodiment more clearly, the following briefly introduces the accompanying drawings used in the description of the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For those skilled in the art, other drawings can also be obtained from these drawings without creative effort.

FIG. 1 is a comparison diagram of the effects of grayscale images corresponding to different bit depths in the prior art.

FIG. 2 is a DMD binary PMW timing modulation method and a modulation example in the prior art.

FIG. 3 is a schematic diagram of the working principle of a DLP display system in the prior art.

FIG. 4 is a dynamic control curve of a single DMD lens in the prior art in the overturned or immobile state.

FIG. 5 is a schematic structural diagram of a dual spatial light modulator display system in the prior art.

FIG. 6 is a schematic structural diagram of a projection system provided by an embodiment of the present invention.

FIG. 7 is a schematic structural diagram of a beam splitter wheel provided by an embodiment of the present invention.

FIG. 8 is a schematic structural diagram of a fluorescent wheel provided by an embodiment of the present invention.

detailed description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative work, all belong to the scope of protection of this application.

In order to better understand the application, the following briefly describes the related technologies involved in the implementation of the application:

Bit depth, also known as color depth, refers to the number of bits required to represent the grayscale information of a pixel in a grayscale image. The larger the bit depth, the more bits required, the smaller the difference between adjacent grayscale values, the less obvious the numerical sampling of analog information, and the more natural and smooth the transition of grayscale differences in the image. Please refer to Figure 1, which shows the comparison of the effect of grayscale images corresponding to different bit depths, such as error! Reference source not found. As shown in figure a in the middle, the grayscale image with a display bit depth of 1 has only 2 ¹ = 2 states, namely bright and dark; as shown in figure b in Figure 1, the image pixel with a display bit depth of 8 can have 2 ⁸ = 256 grayscale states, i.e.

Among them, _Im is the maximum brightness that can be displayed, and the grayscale mode image at this time has 256 possible gray values, which can display more details on the screen. Optionally, another concept related to bit depth is called the least significant bit (LSB), which corresponds to the grayscale difference between two adjacent grayscales in the display. For a grayscale display with a bit depth of n, LSB corresponding luminance I _m / 2 ^n.

DMD (Digital Micromirror Device, digital micromirror chip) realizes the adjustment of the grayscale of a single pixel by regulating the time duty cycle of the on state of a single micromirror. Assuming that DMD can realize 15-bit RGB display within one frame (1/60=16.67ms), and the three RGB color timings are evenly distributed, that is, one color sub-frame can realize 5-bit grayscale display. ^{2 5} = 32 flips in each color lighting time, and the time required to complete each flip is

Corresponds to the time when the LSB is flipped. As shown in FIG. 2 , in an implementation manner, the time corresponding to the LSB+1 bit may be doubled, and the time corresponding to the higher bit may be doubled sequentially. It is worth noting that each flip of the DMD's micromirror can be independently controlled.

In the existing DLP (digital light processing, digital light processing) display system, as shown in Figure 3, uniform and stable light is irradiated on the DMD, by controlling the time that a single mirror in the previous frame of the DMD is in the "on" state The gray value of the corresponding pixel is controlled by the ratio, and the minimum gray value that can be achieved depends on the operation time corresponding to the LSB. The time required for a single lens to flip from one state to another is called the crossover time, which is about a few microseconds, and varies slightly with different processes and structures. As shown in Figure 4, the time that can be switched between two consecutive states is called the switching time, which is about 15 to 20 microseconds. The faster the state switching speed of the DMD micromirror is, that is, the smaller the proportion of time that the minimum grayscale value LSB is in the "on" state, the lower the corresponding brightness. Therefore, the proportion of a single switching time (switching time) in the time required to display a frame of grayscale image determines the brightness of the LSB.

Optionally, for a single DMD RGB three-color projection display system, if the frame rate is 60Hz, the average time corresponding to each color is

Assuming that the minimum gray value LSB is 20us, at this time, the number of switching times that can be achieved for the primary color light in each frame of the DMD is 5560us÷20us=278>255, so the maximum can be achieved about 2 ⁸ -1 = 255 switching times, so for a single DMD In the projection display system, the bit depth corresponding to each color of RGB is generally 8 bits.

Two-chip DLP projection systems usually use a phosphor wheel to complete the temporal separation of colors. Use the fluorescence with the green band in the fluorescence spectrum and the green color correction sheet to obtain the green primary color light, and use the fluorescence with the red wavelength band in the fluorescence spectrum with the red color correction sheet to obtain the red light. The principle of dividing different color areas in the fluorescent wheel is usually that if the spatial light modulator is kept in a fully open state, the light exiting the lens can be mixed into white within one rotation of the fluorescent wheel.

The existing dual spatial light modulator projection display system is shown in FIG. 5 , the blue laser emitted by the laser 102 is divided into transmitted and reflected light beams in sequence after passing through the beam splitter wheel 400, and the transmitted part passes through the anti-blue lens 301 and the uniform light component 303. , After the relay lens group 304, after passing through the beam splitting prism 305, the TIR (Total Internal Reflection, total internal reflection) prism 306 enters the spatial light modulator 501, and finally passes through the prism 308 to combine the light and then projects from the lens 309 on the screen; the reflection part The yellow fluorescence is excited by the collection lens group 302 and incident on the fluorescence wheel 401. The yellow fluorescence passes through the collection lens group 302, two yellow-transmitting blue plates 301, the uniform light assembly 303, and the relay lens group 304, and then exits through the beam splitting prism 305. The red primary color light and the green primary color light are incident on the spatial light modulator 501 by the TIR prism 306, and the green primary color light is incident on the spatial light modulator 502 by the TIR prism 307, and finally combined by the prism 308 and projected on the screen from the lens 309 .

A blue laser with a wavelength of 455 nm can be used as the blue primary color light, and the excited laser light excited by it is the red and green primary color light. If the laser light generated by exciting a typical yellow phosphor is separated at 590nm to obtain the green primary color light in the short-band part and the red primary color light in the long-band part, the color coordinates of the RGB primary color light are R: (0.649,0.350 ), G: (0.325, 0.630), B: (0.151, 0.023). When the recommended white point with coordinates (0.313, 0.329) is generated by the combination, the luminance ratios of the three primary colors are R: 19.6%, G: 77.5%, and B: 2.9%, respectively. Since both the green primary color light and the red primary color light are excited by the blue laser and generated by the laser, there is a proportional relationship between the luminous flux of the blue laser and the excited red and green received laser light. It is assumed that a blue laser with a luminous flux of 1 lumen can be excited to produce 0.78 lumens of red received laser light. Laser and 3.82 lumens green subject to laser. Then it is calculated that the angles corresponding to the blue transparent area and the anti-blue area of the light splitter wheel 400 are 37° and 323°, respectively.

If the display frame rate is 60Hz, and the minimum turn-on time of the spatial light modulator is 15us, corresponding to the least significant bit LSB, the number of grayscale states that can display green primary color light is (323°)/(360°)×1/60s× 1/15us+1=998, but for white balance consideration, the total turn-on time of green light in each frame cannot exceed

Therefore, the actual number of grayscale states that can be displayed is 11.9ms/15us+1=797>2 ⁹ , and a 9-bit bit depth can be realized. The number of grayscale states that can display blue primary color light is (37°)/(360°)×1/60s×1/15us+1=115>2 ⁶ , which can achieve 6-bit bit depth. It can be seen that each primary color light can achieve The bit depth is average and cannot present more image details.

Optionally, in the dual-chip DLP projection display system, a light splitter wheel can be used to separate the blue light and yellow light in the time domain, and then the red and green light is divided into two spatial light modulators by the red and green light splitting film for processing. . Assuming that the luminous fluxes of the RGB monochromatic lights when their respective time duty ratios are 100% are Φ _R , Φ _G , and Φ _B , respectively, using the principle of additive color mixing, it can be obtained that the ratio of lumens when the RGB primary color light is mixed into the specified white light is ρ _R , Φ G , and Φ B , respectively. ρ _G , ρ _B . _{Then the total angles θ B} and θ _Y of each primary color light on the beam splitter wheel can be calculated using the following formula (where t _R , t _G , and t _B are the time durations for displaying RGB color light when white light is synthesized):

Among them, if the B primary color light and the R primary color light are controlled by the same spatial light modulator, the calculation formula can be:

If the B primary color light and the G primary color light are controlled by the same spatial light modulator, the calculation formula can be:

The embodiments of the present application will be described in detail below with reference to the accompanying drawings.

first embodiment

Referring to FIG. 6 and FIG. 7 , the present invention provides a projection system 1 , which includes a laser light source 10 , a beam splitter wheel 20 , a fluorescent wheel 30 and a light processing system 40 . The laser light source 10 is used to emit excitation light. The beam splitter wheel 20 includes a partial beam splitting area 21 and a guide area 23. The partial beam splitting area 21 is used to divide the excitation light emitted by the laser light source 10 into a first excitation light and a second excitation light. The excitation light exits along the second optical path, and the guide area 23 is used to guide the excitation light exiting from the laser light source to exit along the second optical path. The fluorescent wheel 30 is used for converting the second excitation light from the second optical path into the first received laser light, and for converting the excitation light emitted from the laser light source into the second received laser light, wherein the first received laser light can pass the filter of the fluorescent wheel 30 . The light area is divided into the third received light beam or the fourth received light beam, or the mixed light of the third received light beam and the fourth received light beam. The light processing system 40 includes a light splitting element 42, a first spatial light modulator 43 and a second spatial light modulator 44, the light splitting element 42 is used for guiding the first excitation light from the first optical path to the first spatial light modulator 43, The beam splitter 42 is used to guide the third or fourth received laser light filtered from the first received laser light to the first spatial light modulator 43 or the second spatial light modulator 44, and divide the second received laser light into the The third received laser light of the first spatial light modulator 43 and the fourth received laser light entering the second spatial light modulator 44, or the second received laser light is divided into the fourth received laser light entering the first spatial light modulator 43 and the fourth received laser light entering the first spatial light modulator 43. The third received laser light of the two spatial light modulators 44 . It can be understood that, if the third received laser light enters the first spatial light modulator 43, then the fourth received laser light enters the second spatial light modulator 44; if the third received laser light enters the second spatial light modulator 44, at this time The fourth received laser light enters the first spatial light modulator 43 .

Specifically, the laser light source 10 may include a laser, and the laser may be a single laser, a laser chip or a laser diode, etc., or other laser emitting devices. It can be understood that the laser light source 10 can also include two, three or more lasers, the multiple lasers can be arranged in an array to increase the light intensity of the lasers, and the multiple lasers can also be arranged non-uniformly.

In this embodiment, the laser light source 10 may be a blue light source, and the corresponding excitation light is a blue laser. Since the cost of blue light sources is lower, the use of blue light sources can reduce costs. The blue laser is used as the primary color light and as the excitation light to excite the other two primary color lights of red light and green light, so that it can be mixed into white light and emitted.

In this embodiment, the beam splitter wheel 20 is annular, and the middle of the beam splitter wheel 20 may be an invalid area, which may be provided with glass or other materials. The surrounding area is the functional area. In other embodiments, the beam splitter wheel 20 may also be one of a circle, a rectangle, an ellipse or a trapezoid.

In this embodiment, the transmittance of the partial light-splitting area 21 is equal to the reflectance of the partial light-splitting area 21. Specifically, the partial light-splitting area 21 has a thin film with a blue light transmittance of 50% and a reflectance of 50%. The form of pasting or plating is provided in part of the light splitting area 21 . That is, the excitation light is divided into the first excitation light and the second excitation light emitted along different optical paths by the partial beam splitting area 21 . The first excitation light can be used as blue primary color light, which is modulated by the first spatial light modulator 43 and then emitted; the second excitation light is used to excite the received laser light. Due to the setting of the partial light splitting area 21, the light power of the blue primary color used for display becomes weak. For the consideration of white balance, the timing ratio of the partial light splitting area 21 on the light splitting wheel 20 can be increased to increase the corresponding The proportion of the blue transparent timing sequence is increased, thereby improving the modulation bit depth of the projection system 1 .

The guide area 23 has a blue light reflection film, and the blue light reflection film can also be provided on the guide area 23 in the form of pasting or plating. The guide area 23 is used to reflect the excitation light emitted by the laser light source to the fluorescent wheel 30 .

In this embodiment, the angle corresponding to the partial light splitting area 21 and the guiding area 23 can be obtained by calculation. As an example, a blue laser with a wavelength of 455 nm is used as the blue primary color light, and the received laser light excited by it is the red and green primary color light. The short-band part is green primary color light, and the long-band part is red primary color light, then the color coordinates of RGB primary color light are R: (0.649, 0.350), G: (0.325, 0.630), B: (0.151, 0.023) ). When the recommended white point with coordinates (0.313, 0.329) is generated by the combination, the luminance ratios of the three primary colors are R: 19.6%, G: 77.5%, and B: 2.9%, respectively. Since both the green primary color light and the red primary color light are generated by the blue laser excitation and received laser light, there is a proportional relationship between the luminous flux of the blue laser and the excited red and green received laser light. The measurement data show that a blue laser with a luminous flux of 1 lumen can excite 0.78 lumens of red laser light and 3.82 lumens of green received laser light. Considering the white balance, the angles of the light splitting area 21 and the anti-blue guide area 23 on the light splitter wheel 20 can be calculated to be 67.5° and 292.5°, respectively.

Specifically, the angle calculation method of the partial beam splitting area 21 and the guide area 23 of the beam splitting wheel 20 is as follows:

first by

where i=R,G,B

Calculate the RGB display time ratio. In the formula ρ _R : ρ _G : ρ _B =19.6%: 77.5%: 2.9%

Φ _R : Φ _G : Φ _B =0.78lm: 3.82lm: 1lm

Calculated t _R : t _G : t _B =52.01%: 41.99%: 6%

If the red primary color light and the blue primary color light are processed by the first spatial light modulator 43, and the green primary color light is processed by the second spatial light modulator 44, since half of the blue excitation light in part of the light splitting area 21 is used for blue primary color light display, half blue The excitation light excites the fluorescence for the green primary color light display, because the above time can be converted into:

t _R : t _G : t _B = 52.01%: 35.99%: 12%

At this time, the angle of the semi-transparent and semi-reflective area is

The angle of the anti-blue area is 292.5°;

If the green primary color light and the blue primary color light are processed by the first spatial light modulator 43, and the red primary color light is processed by the second spatial light modulator 44, since half of the blue excitation light in part of the light splitting area 21 is used for blue primary color light display, half blue The excitation light excites fluorescence for red primary color light display, because the above time can be converted into:

t _R : t _G : t _B = 46.01%: 41.99%: 12%

At this time, the angle of the semi-transparent and semi-reflective area is

The angle of the anti-blue area is 280°;

Taking the red primary color light and the blue primary color light processed by the first spatial light modulator 43 and the green primary color light processed by the second spatial light modulator 44 as an example, if the display frame rate is 60 Hz, and the shortest turn-on time of the spatial light modulator is 15~20us, corresponding to the least significant bit LSB, at this time, the number of grayscale states that can display blue primary color light is (67.5°)/(360°)×1/60s×1/15us+1=209>2 ⁷ , which can be A 7-bit bit depth is achieved, which is greater than the 6-bit bit depth of the dual spatial light modulator projection display system in the prior art. Assuming that the transmittance and reflectivity of the partial light splitting area 21 to the blue excitation light are both 50%, when the intensity of the green primary color light corresponding to the guiding area 23 is 1, the minimum brightness corresponding to the displayed least significant bit can be

Then the green primary color light intensity corresponding to the partial light splitting area 21 is 0.5I, and the minimum brightness corresponding to the least significant bit can be

Since I _m2 <I _m1 _{, I m2} can be selected as the minimum brightness corresponding to the LSB for calculation. For the consideration of white balance, the maximum intensity of green primary color light is 0.8I=1789I _m2 . Then the set of green grayscales actually encoded and displayed is {0,I _m2 ,I _m2 ,3I _m2 ,...1789I _m2 }, and 1790>2 ¹⁰ means that the maximum bit depth that can be displayed is 10 bits, which is larger than the double space in the prior art 6-bit depth of light modulator projection display system. It should be noted that the calculation of the bit depth corresponding to the red primary color light is the same as that of the green primary color light, and will not be listed again.

It can be seen that by setting the partial light splitting area 21 as a transflective structure, the amount of blue light as the excitation light increases, which further increases the amount of green light or red light generated by wavelength conversion of the excitation light. During the period, the increased green light or red light can be modulated and output by another spatial light modulator, and the modulation of green light or red light can be further increased, so that the bit depth of green light or red light can be increased; The transflective structure will reduce the brightness of the blue primary color light used for display, so that the timing ratio of the blue primary color light in the case of exiting the preset white point must increase, that is, the total duration of the blue segment in each frame time increases, and then can The number of gray-scale states for displaying blue primary color light is increased, so the bit depth of blue light is also increased. Therefore, part of the light-splitting area 21 of the light-splitting wheel 20 in this embodiment is a transflective structure, which can increase the bit depths of red light, green light and blue light at the same time, thereby improving the display bit depth of the projection system.

6 and 8 , the phases of the fluorescence wheel 30 and the spectroscope wheel 20 are synchronized, wherein the phase synchronization means that the rotation speed of the spectroscope wheel 20 and the fluorescence wheel 30 are the same and their positions correspond during the rotation. The fluorescent wheel 30 includes a light conversion area 32 and a light guide area 34 that are concentrically arranged. The light guide area 34 surrounds the light conversion area 32, and the light guide area 34 is also located on the side of the light conversion area 32 away from the beam splitter wheel 20. In this embodiment, the light guide area 34 can be attached to the light conversion area 32. Bonding by welding or bonding. In other embodiments, the light guide region 34 may also be integrated with the light conversion region 32 .

The light conversion area 32 is used for converting the second excitation light and the excitation light emitted from the laser light source into the first received laser light and the second received laser light, respectively. Specifically, the light conversion area 32 includes a first light conversion area 322 and a second light conversion area 324, the first light conversion area 322 is used for converting the second excitation light into the first received laser light, and the second light conversion area 324 is used for The excitation light emitted by the laser light source is converted into the second received laser light. In this embodiment, both the first light conversion area 322 and the second light conversion area 324 are coated with yellow phosphor powder, so the first received laser light and the second received laser light are the same color light (yellow received laser light), it can be understood that In other embodiments, the first light conversion area 322 and the second light conversion area 324 may be provided with phosphors of different colors, and emit laser light of different colors. The central angle corresponding to the first light conversion area 322 is equal to the central angle corresponding to the partial beam splitting area 21, so that the second partial laser can be accurately incident on the first light conversion area 322 of the fluorescent wheel 30, and the excitation of the laser light source can be guaranteed. The light can be accurately incident to the second light conversion area 324 of the fluorescent wheel 30 .

The light guide region 34 is used for filtering the first received laser light to emit the third received laser light and the second received laser light. Specifically, the light guide area 34 includes a first light guide area 341 and a second light guide area 343, wherein the first light guide area 341 corresponds to the first light conversion area 322, and the first light guide area 341 is used to The laser light is modified into the third laser light or the fourth laser light or the mixed light of the third laser light and the fourth laser light, and is guided to the light splitting element 42; the second light guide area 343 corresponds to the second light conversion area 324, and is The second laser light is guided to the beam splitter 42 . In this embodiment, the first light guide area 341 is used to convert the first received laser light into the fourth received laser light. Specifically, the first light guide area 341 is provided with a green light bandpass filter, and the passband is 480nm～ 590nm, that is, only green light in yellow light is allowed to pass through, and the fourth laser light is green light. In one embodiment, the first light guide area 341 is used to convert the first received laser light into the third received laser light. Specifically, the first light guide area 341 may be provided with a red light bandpass filter, and the third received laser light The laser is red subject to laser light. In another embodiment, the first light guide area 341 is used to convert the first received laser light into a mixed light of the third received laser light and the fourth received laser light, that is, the yellow received laser light. At this time, the first light guide area 341 It can be provided with a yellow light bandpass filter or transparent glass. In this embodiment, the central angle corresponding to the first light guide area 341 is equal to the central angle corresponding to some of the light splitting areas 21 , so that the first received laser light can be accurately incident on the first light guide area 341 , and the second received laser light can be accurately incident to the second light guide region 343 . The second light guide area 343 is provided with a transparent glass, that is, the yellow light is allowed to pass through, that is, the second laser light passes through the transparent glass of the second light guide area 343 and then enters the beam splitter 42 .

The beam splitter 42 is also used to divide the second received laser light into a third received laser light and a fourth received laser light, guide the third received laser light to the first spatial light modulator 43, and guide the fourth received laser light to the second spatial light modulation device 44.

In this embodiment, the first spatial light modulator 43 is used to modulate the first excitation light and the third received light, and the second spatial light modulator 44 is used to modulate the fourth received light.

The projection system 1 further includes a beam splitter wheel controller 50 , a phosphor wheel controller 60 , a first modulation controller 70 and a second modulation controller 80 . The splitter wheel controller 50 can be electrically connected with the splitter wheel 20 to control the rotation of the splitter wheel 20; the fluorescence wheel controller 60 can be electrically connected with the fluorescence wheel 30 to control the rotation of the fluorescence wheel 30; the first modulation control The controller 70 may be electrically connected to the first spatial light modulator 43 for controlling the first spatial light modulator 43; the second modulation controller 80 may be electrically connected to the second spatial light modulator 44 for controlling the second spatial light modulator 44 Spatial Light Modulator 44 . The phases of the first modulation controller 70 , the second modulation controller 80 , the beam splitter wheel 20 and the fluorescence wheel 30 can be controlled by the beam splitter wheel controller 50 , the fluorescence wheel controller 60 , the first modulation controller 70 and the second modulation controller 80 Synchronize.

Please refer to FIG. 6 , FIG. 7 and FIG. 8 , in this embodiment, the projection system 1 further includes a relay system 90 , and the relay system 90 is used for condensing the first excitation light, the fourth received laser light and the second received laser light to The beam splitter 42 can reduce the energy loss during light transmission.

The relay system 90 is located on the first optical path and the second optical path at the same time, and includes a first dichroic plate 91 , a light homogenizer 93 and a relay lens assembly 95 . Wherein, the first dichroic plate 91 is used to reflect the first excitation light and transmit the fourth received laser light and the second received laser light. In this embodiment, the first dichroic plate 91 is a translucent yellow and inverse blue film. In other embodiments, dichroic sheets with different performances may be provided according to different light source devices. The light homogenizer 93 is located between the first dichroic plate 91 and the relay lens assembly 95, and the light homogenizer 93 may be a single fly-eye lens or a fly-eye lens group. The relay lens assembly 95 is used for condensing the first excitation light, the fourth received laser light and the second received laser light to the beam splitter 42 .

The projection system 1 also includes a guide assembly 100 including a second dichroic plate 110 and a reflection assembly 120 . The second dichroic plate 110 and the reflection component 120 are both located in the second optical path. The second dichroic plate 110 is used to guide the second excitation light and the excitation light emitted by the laser light source to the fluorescent wheel 30 and to receive the first laser light. and the second received laser light is directed to the reflective assembly 120 . In this embodiment, the second dichroic sheet 110 is a translucent blue-to-yellow dichroic sheet. The reflection component 120 is used to guide the fourth received laser light and the second received laser light to the first dichroic plate 91 . The reflection assembly 120 includes a first reflection member 121 , a second reflection member 122 and a third reflection member 123 . The first reflector 121 and the second reflector 122 are located on two sides of the fluorescent wheel 30, respectively, and the second reflector 122 and the third reflector 123 are located on the same side of the fluorescent wheel 30 and are opposite to each other. The first reflector 121 is used to reflect the first laser light reflected by the second dichroic sheet 110 to the first light guide area 341 , and to reflect the second laser light to the second light guide area 343 ; the second reflector 122 Used to reflect the fourth received laser light emitted from the first light guide region 341 and the second received laser light emitted from the second light guide region 343 to the third reflection member 123 ; the third reflection member 123 is used to emit the second reflection member 122 The fourth and second laser beams are reflected to the first dichroic plate 91 .

In this embodiment, the guide assembly 100 further includes a collecting lens group 130 and a condensing lens 140 . The collection lens group 130 is located between the second dichroic plate and the light conversion area 32, and is used for condensing the second excitation light transmitted through the second dichroic plate 110 to the light conversion area 32 and excites the generated first received laser light converges to the second dichroic sheet 110 . It is also used to condense the excitation light emitted by the laser light source passing through the second dichroic plate 110 to the light conversion region 32 and to condense the second received laser light generated by excitation to the second dichroic plate 110 . The condensing lens 140 is located between the first reflection member 121 and the light guide area 34 , and is used for condensing the first received laser light to the first light guide area 341 and also for condensing the second received laser light to the second light guide area 343 .

In this embodiment, the light processing system 40 further includes a first total internal reflection prism 45 , a second total internal reflection prism 46 and a light combining device 47 . The first total internal reflection prism 45 is adjacent to the first spatial light modulator 43, and is used for reflecting the third received laser light and the first excitation light emitted by the beam splitter 42 to the first spatial light modulator 43, and the first spatial light modulator 43. The third received laser light and the first excitation light modulated by the spatial light modulator 43 are reflected to the light combining device 47 . The second total internal reflection prism 46 is adjacent to the second spatial light modulator 44 and is used for reflecting the fourth received laser light output from the beam splitter 42 to the second spatial light modulator 44 and modulating the second spatial light modulator 44 The fourth received laser light is reflected to the light combining device 47 . The light combining device 47 is used to combine the first excitation light and the third received laser light modulated and output from the first spatial light modulator 43 and the fourth received laser light modulated and output from the second spatial light modulator 44, and combine them. The light behind the light is emitted to the projection screen. In this embodiment, the light combining device 47 is a light combining prism.

The projection system further includes a lens 200, and the lens 200 is adjacent to the light combining device 47, and is used for projecting and displaying the light combined and emitted from the light combining device 47.

In this embodiment, the first optical path is the path of light passing through the first dichroic plate 91, the relay system 90 to the beam splitter 42; the second optical path is the light passing through the second dichroic plate 110, the collection lens group 130 , the light conversion area 32 of the fluorescent wheel 30 , the collection lens group 130 , the second dichroic plate 110 , the first reflector 121 , and the condensing lens 140 . The light guide area 34 of the fluorescent wheel 30 , the second reflector 122 , the third reflector 123 , the first dichroic plate 91 , the relay system 90 and the transmission path of the beam splitter 42 .

To sum up, the first spatial light modulator 43 and the second spatial light modulator 44 of the projection system 1 provided by the present invention can work for full time, and by setting part of the light splitting area 21 as a semi-transparent and semi-reflective structure, the excitation light can be used as the excitation light. The amount of blue light increases, which further increases the amount of green or red light generated by wavelength conversion of the excitation light. During the modulation period of the blue primary color light, the increased green or red light can be modulated and emitted by another spatial light modulator. Further increase the modulation of green light or red light, so that the bit depth of green light or red light increases; in addition, setting part of the light splitting area 21 as a transflective structure will reduce the brightness of the blue primary color light used for display, so that in the output preset In the case of white field, the proportion of blue primary color light sequence must be increased, that is, the total duration of the blue segment in each frame time increases, and then the number of grayscale states that can display blue primary color light increases, so the bit depth of blue light is also improved. The display bit depth of the projection system 1 is improved.

Second Embodiment

Referring to FIG. 7 , the difference from the first embodiment is that the transmittance T of the partial light splitting area 21 in this embodiment is greater than the reflectance R of the partial light splitting area 21 , that is, T>R. Since the brightness of the blue primary color light used for display decreases, the proportion of the total duration of the blue segment in each frame time increases, and the number of grayscale states that can display the blue primary color light will still increase. For green light, the minimum brightness corresponding to the least significant bit displayed in the guide area 23 is I _m1 , the green light intensity in the partial light splitting area 21 is R*I, and the minimum brightness corresponding to the least significant bit may be min(I _m2 ) =R×I _m1 , the “on” duration corresponding to the least significant bit of the green light can be increased in the partial light splitting area 21 of the light splitting wheel 20, so that I _m2 =0.5I _m1 , the grayscale set with the same increment interval can still be obtained {0,I _m2 ,I _m2 ,3I _m2 ,…NI _m2 }, increase the display bit depth of green light. The same is true for red light.

Third Embodiment

Referring to FIG. 7 , the difference from the first embodiment is that the transmittance T of the partial beam splitting area 21 in this embodiment is smaller than the R reflectance of the partial beam splitting area 21 , that is, T<R. Since the brightness of the blue primary color light used for display decreases, the total duration of the blue segment in each frame time increases, and the number of grayscale states capable of displaying the blue primary color light will still increase. For green light, the minimum brightness corresponding to the least significant bit displayed in the guide area 23 is I _m1 , the green light intensity in the partial light splitting area 21 is R*I, and the minimum brightness corresponding to the least significant bit may be min(I _m2 ) =R×I _m1 , the “on” duration corresponding to the least significant bit of the green light can be increased in the lead area 23 of the beam splitter wheel 20, so that I _m1 =2I _m2 , the grayscale set {0 with the same increment interval can still be obtained ,I _m2 ,I _m2 ,3I _m2 ,…NI _m2 }, increase the display bit depth of green light. The same is true for red light.

Fourth Embodiment

Referring to FIG. 8 , the difference from the first embodiment is that the first light conversion area 322 and the second light conversion area 324 provided in this embodiment are coated with phosphors of different colors. Specifically, the first light conversion area 322 is coated with phosphors of different colors. There is green light phosphor powder or red light phosphor powder, and the second light conversion area 324 is coated with yellow light phosphor powder. At this time, the first received laser light converted by the first light conversion region 322 is green fluorescence or red fluorescence, and the second received laser light is yellow fluorescence of a different color from the first received laser light. The beam splitter 42 is also used to convert the second laser beam into a third beam receiver and a fourth beam receiver. It should be noted that in this embodiment, the third beam receiver divided by the beam splitter 42 is red light, and the fourth beam receiver is red light. For red light, the third received laser light is guided to the first spatial light modulator 43, and the fourth received laser light is guided to the second spatial light modulator 44; in addition, the beam splitter 42 is also used to guide the first excitation light to the second spatial light modulator 44. a spatial light modulator 43 for guiding the first received laser light to the second spatial light modulator 44; the first spatial light modulator 43 is used to modulate the first excitation light and the third received laser light, and the second spatial light modulator 44 uses for modulating the first received laser light and the fourth received laser light. For the sake of white balance, the proportion of the three primary colors of RGB has changed, and the luminous flux of the blue laser has a proportional relationship with the excited red and green fluorescence. For similar reasons, the light source structure 1 provided in this embodiment can still improve the display bit depth, which will not be described here.

Fifth Embodiment

Referring to FIG. 6 , the difference from the first embodiment is that the fourth received laser light of the light source structure 1 provided in this embodiment is guided to the first spatial light modulator 43 to be modulated and then emitted, and the third received laser light is guided to the second received laser light. The spatial light modulator 44 is modulated and then emitted. The light source structure 1 provided in this embodiment can still improve the display bit depth.

The above-mentioned embodiments only represent several embodiments of the present invention, and the descriptions thereof are specific and detailed, but should not be construed as a limitation on the scope of the patent of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can also be made, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention should be subject to the appended claims.

Claims

A projection system, characterized in that, comprising:

Laser light source for emitting excitation light;

The beam splitting wheel includes a partial beam splitting area and a guide area, the partial beam splitting area is used to divide the excitation light emitted by the laser light source into a first excitation light and a second excitation light, the first excitation light is emitted along the first optical path, and the The second excitation light is emitted along the second optical path, and the guide area is used to guide the excitation light emitted by the laser light source to be emitted along the second optical path;

The fluorescent wheel is used to convert the second excitation light from the second optical path into a first received laser light, convert the excitation light emitted by the laser light source into a second received laser light, and convert the first received laser light into a second received laser light. a third received laser light or a fourth received laser light or a mixture of said third received laser light and said fourth received laser light; and

a light processing system, comprising a light splitting element, a first spatial light modulator and a second spatial light modulator, the light splitting element is used for guiding the first excitation light from the first optical path to the first spatial light modulator, and the The third received laser light or the fourth received laser light is guided to the first spatial light modulator or the second spatial light modulator, and the second received laser light is guided to the first spatial light modulation and the second spatial light modulator.
The projection system according to claim 1, wherein the second received laser light and the first received laser light are light of different colors, and the light splitting element is further configured to divide the second received laser light into a third received laser light and a fourth received laser light, the third received laser light is guided to the first spatial light modulator, and the fourth received laser light is guided to the second spatial light modulator; the first spatial light modulation The second spatial light modulator is used to modulate the first excitation light and the third received light, and the second spatial light modulator is used to modulate the fourth received light.
The projection system according to claim 1, wherein the second received laser light and the first received laser light are of the same color, and the light splitting element is further used to separate the first received laser light and the second received laser light. The received laser light is divided into a third received laser light and a fourth received laser light, the third received laser light is guided to the first spatial light modulator, and the fourth received laser light is guided to the second spatial light modulator; The first spatial light modulator is used to modulate the first excitation light and the third received light, and the second spatial light modulator is used to modulate the fourth received light.
The projection system according to claim 1, wherein the projection system further comprises a beam splitter wheel controller and a fluorescence wheel controller, the beam split wheel controller is used to control the rotation of the beam splitter wheel, and the fluorescence wheel controls the rotation of the beam splitter wheel. The device is used to control the rotation of the fluorescent wheel, and the phase of the light splitter wheel and the fluorescent wheel is synchronized.
The projection system according to claim 4, wherein the projection system further comprises a first modulation controller and a second modulation controller, the first modulation controller is used to control the first spatial light modulator, The second modulation controller is used to control the second spatial light modulator, and the first modulation controller, the second modulation controller, the light splitting wheel and the fluorescent wheel are phase-synchronized.
The projection system according to claim 1, wherein the phosphor wheel comprises a light conversion area and a light guide area arranged concentrically, the light guide area surrounds the light conversion area, and the light conversion area is used for converting The second excitation light and the excitation light emitted by the laser light source are respectively converted into the first received laser light and the second received laser light, and the light guide area is used to convert the first received laser light and the second received laser light. Both of the two received laser beams are guided to the beam splitter.
The projection system according to claim 6, wherein the light conversion area comprises a first light conversion area and a second light conversion area, and the first light conversion area is used for converting the second excitation light into The first received laser light and the second light conversion area are used to convert the excitation light emitted by the laser light source into the second received laser light, and the light guide area includes a first light guide area and a second light guide area The first light guide area corresponds to the first light conversion area for guiding the first received laser light to the beam splitter, and the second light guide area corresponds to the second light conversion area an area for guiding the second laser light to the beam splitter.
The projection system according to claim 7, wherein the central angle corresponding to the first light conversion area is equal to the central angle corresponding to the partial light splitting area.
The projection system according to claim 1, wherein the transmittance of the partial light splitting area is equal to the reflectance of the partial light splitting area.
The projection system according to claim 1, wherein the transmittance of the partial light splitting area is greater than the reflectance of the partial light splitting area.
The projection system according to claim 1, wherein the transmittance of the partial light splitting area is smaller than the reflectance of the partial light splitting area.
The projection system according to claim 1, wherein the projection system further comprises a lens, and the light processing system further comprises a light combining device, the light combining device is used for combining the light from the first spatial light modulator The modulated outgoing light and the modulated outgoing light from the second spatial light modulator are combined and incident on the lens, which is used for projection.
The projection system according to claim 1, characterized in that, the projection system further comprises a relay system, the relay system comprises a first dichroic plate, a diffuser and a relay lens assembly, the first The dichroic plate is used to reflect the first excitation light and transmit the first received laser light and the second received laser light, and the light homogenizer is located on the first dichroic plate and the relay lens assembly In between, the relay lens assembly is used for condensing the first excitation light, the first received laser light and the second received laser light to the beam splitter.
The projection system of claim 1, wherein the projection system further comprises a guide assembly comprising a second dichroic plate and a reflection assembly, the second dichroic plate and the reflection assembly The components are all located in the second optical path, and the second dichroic plate is used to guide the second excitation light and the excitation light emitted from the laser light source to the phosphor wheel, and to transmit the first laser light to the phosphor wheel. and the second received laser light are guided to the reflective assembly for guiding the first received laser light and the second received laser light to the first dichroic plate.