WO2022002189A1

WO2022002189A1 - Light source and projection apparatus

Info

Publication number: WO2022002189A1
Application number: PCT/CN2021/103950
Authority: WO
Inventors: 陈晨; 龚晨晟; 胡飞; 余新; 李屹
Original assignee: 深圳光峰科技股份有限公司
Priority date: 2020-07-03
Filing date: 2021-07-01
Publication date: 2022-01-06
Also published as: CN113885281A

Abstract

Disclosed in the embodiments of the present application are a light source and a projection apparatus. The light source comprises a laser light source and a color wheel; the color wheel comprises at least two partitions; different partitions are irradiated by the laser light source and then generate light of different primary colors, or different partitions are used for changing the direction of the light path of the laser light source; and the proportion of each partition is relatively balanced, and is set to be a preset proportion and used for improving a display frame rate. The light source provided by the present embodiment sets the proportion of the partition of the color wheel to be a relatively balanced preset proportion, so that the light of the primary colors corresponding to different partitions is combined and then can meet a preset color balancing standard, and thus, the time duty ratio of the light of each primary color can be more balanced when a white field is displayed, thereby achieving the improvement of the display frame rate while keeping a display effect.

Description

Light source and projection device

technical field

The present application relates to the technical field of laser display, and more particularly, to a light source and a projection device.

Background technique

In recent years, people's requirements for the effect of projection display have been continuously improved, and laser light sources have been widely used in the display field (such as projection field). In the field, laser light sources have gradually replaced light bulbs and LED light sources. Among them, the light source that uses a laser light source to excite phosphors to generate the required light (such as blue laser excitation of red and green phosphors to generate white light) has become the mainstream of applications due to its advantages of high light efficiency, good stability and low cost. However, in the laser projection display, the display frame rate will gradually decrease as the display continues, thereby affecting the display effect of the projection image.

As a method, the display frame rate can be increased by increasing the rotation speed of the color wheel or using a multi-segment color wheel. However, when the display frame rate is increased by these methods, if the rotation speed of the color wheel is increased, the display of a single primary color light in each frame will be reduced. The time will decrease accordingly, which may result in a decrease in the color bit depth, which in turn affects the display effect of the projected image. However, if a multi-segment color wheel is used to increase the display frame rate, when the color wheel division increases, the division angle of each primary color light will decrease accordingly, which may lead to problems such as increased synchronization accuracy requirements of the color wheel and reduced light efficiency, thereby reducing projection. The display effect of the screen.

SUMMARY OF THE INVENTION

In view of the above problems, the present application proposes a light source and a projection device to improve the above problems.

In a first aspect, an embodiment of the present application provides a light source, the light source includes: a laser light source; and a color wheel, the color wheel includes at least two subsections, and different subsections are illuminated by the laser light source to generate different primary color lights , the proportion of the partitions is relatively balanced, and is set to a preset proportion for improving the display frame rate.

In a second aspect, an embodiment of the present application provides a projection device, where the projection device adopts the light source described in the first aspect.

The application provides a light source and a projection device, the light source includes: a laser light source; a color wheel, the color wheel includes at least two subsections, and different subsections are irradiated by the laser light source to generate different primary color lights or different subsections For changing the light path direction of the laser light source, the proportion of the partitions is relatively balanced, and is set to a preset proportion to improve the display frame rate. In the light source provided in this embodiment, by setting the division ratio of the color wheel to a relatively balanced preset ratio, the primary color lights corresponding to different divisions can be synthesized to meet the preset color balance standard, and each primary color light can meet the preset color balance standard when displaying white point. The time duty cycle can be more balanced, thereby improving the display frame rate while maintaining the display effect.

Description of drawings

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

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

FIG. 2 shows an example diagram of an application environment of the light source proposed by the embodiment of the present application.

FIG. 3 shows an example diagram of the distribution of blue laser current and color wheel timing in the prior art.

FIG. 4 shows an example diagram of the distribution of blue laser current and color wheel timing in the present application.

FIG. 5 shows a front view of the red, green and blue wheels proposed by the embodiment of the present application.

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 making creative efforts shall fall within the scope of protection of this application.

In recent years, as projection technology has been widely used in various applications such as movie playback, conferences and publicity, people's requirements for the effect of projection display are also increasing. Light source, because laser light source has the advantages of high energy density and small etendue, in the field of high-brightness light source, laser light source has gradually replaced light bulbs and LED light sources. Among them, the light source that uses a laser light source to excite phosphors to generate the required light (such as blue laser excitation of red and green phosphors to generate white light) has become the mainstream of applications due to its advantages of high light efficiency, good stability and low cost. However, in the laser projection display, the display frame rate will gradually decrease as the display continues, thereby affecting the display effect of the projection image.

Therefore, in order to improve the above problems, the inventor proposes a light source provided by the present application. By setting the division ratio of the color wheel to a relatively balanced preset ratio, the primary color light corresponding to different divisions can be synthesized to satisfy the preset ratio. The color balance standard, and the time duty ratio of each primary color light can be more balanced when displaying a white point, so as to improve the display frame rate while maintaining the display effect.

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 Fig. 1, which shows a comparison chart of the effects of grayscale images corresponding to different bit depths. As shown in Fig. 1, a grayscale image with a bit depth of 1 only has 2 ¹ =2 states, namely bright and dark; An image pixel with a display bit depth of 8 can have 2 ⁸ =256 grayscale states, namely

where _Im is the maximum brightness that can be displayed. 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) adjusts 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 LSB (least significant bit) is flipped. As a way, the time corresponding to the LSB+1 bit may be doubled, and the time corresponding to the higher bit may be doubled in turn. It is worth noting that each flip of the DMD micromirror can be independently controlled, that is, each flip of the DMD bit plane is independent, which is used to match the high refresh rate of the lighting to reduce the color breakup phenomenon. Very important.

In the existing DLP (digital light processing) display system, uniform and stable light is illuminated on the DMD (digital micromirror device), and the corresponding mirror is controlled by controlling the proportion of the time that a single mirror is in the "on" state in the previous frame of the DMD. The gray value of the pixel, 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, with slight differences in different processes and structures. The time that can be switched between two consecutive states is called the switching time, which is about 20 microseconds. 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

^{About 2 8} -1 = 255 switching times can be achieved, so for a single DMD projection display system, the bit depth corresponding to each color of RGB is generally 8 bits.

The blue light laser used in the light source of the projector generally has a lifespan of about 20,000 hours. Under normal operation conditions, the aging of the laser is generally gradual degradation, that is, during the working process, the material is exposed to a large amount of electrons. After the holes are combined, the non-luminescent centers gradually increase, and the cavity surface of the resonator gradually ages. Another common laser damage mechanism is catastrophic optical damage (COD: catastrophic optical damage). The material is melted or recrystallized to further enhance the light absorption, thereby forming a process of positive feedback, which eventually causes the mirror surface of the laser resonator to fail and cause damage to the laser. Unlike gradual aging, COD is much more rapid, manifesting as a sudden decrease in brightness. The laser luminous flux threshold for COD is related to the pulse length of the laser, (Chin AK, et al, (2013) Catastrophic optical damage in high-power, broad-area laser diodes. In: Ueda O., Pearton S.(eds) Materials and reliability handbook for semiconductor optical and electron devices. Springer, New York, NY). In the pulse operation mode, the time duty cycle of the on state is less than 1, and the average heat generation power is lower than the heat generation power of the same optical power in the CW mode, so it can withstand stronger optical power. That is to say, in the pulse working mode, the brightness of the illumination of the laser light source can be improved compared with the CW working mode.

In laser projectors, the pulse duration of the current is generally in the order of milliseconds (ms) (compared to the general microsecond or even nanosecond order, which is called long pulse here), so if it is only a few times (about 5 times) ) increase the driving current, the COD phenomenon is not obvious, that is, the optical power output under the reference current set by the laser does not reach the level of COD phenomenon, and the laser damage is more caused by the gradual aging process. In this case, the inventors of the present application found that the brightness of the laser can be increased in a short time by means of an overdrive pulse current. It should be noted that, overdrive here means that the driving current used exceeds the maximum absolute operating current parameter of the laser (Absolute maximum ratings of operating current).

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

Please refer to FIG. 2 , which is an example diagram of an application environment of the light source proposed by the embodiment of the present application. As shown in FIG. 2 , the light source provided in this embodiment may include a laser light source 202 , a color wheel 301 , and a power control module 203 . Wherein, the laser light source 202 can be a blue laser, and in some possible implementations, the laser light source 202 can also be a light emitting diode, a laser diode or other solid-state light source; the color wheel 301 can include at least two partitions, and the color wheel 301 is a dichroic color wheel The wheel, optionally, is used to change the direction of the light path of the laser light source after different sections are irradiated by the laser light source 202 . In other embodiments, the color wheel can also be a fluorescent color wheel, and different sub-areas can be set to generate different primary color lights.

For example, as an embodiment, the color wheel may be a yellow-blue color wheel, and in this manner, at least two subsections of the color wheel may include a yellow subsection and a blue subsection. Among them, the yellow subregion can transmit blue light after being irradiated by a laser light source, and then excite the fluorescent color wheel in the following optical path to generate yellow light, and the blue subregion can generate blue primary color light after being irradiated by a laser light source. After being irradiated by the laser light source 202, the different subregions are used to change the light path direction of the laser light source. As another embodiment, the color wheel may be a red, green, and blue wheel, and in this manner, at least two subsections of the color wheel may include a red subsection, a green subsection, and a blue subsection. Among them, the red subregion can generate red primary color light after being irradiated by laser, the green subregion can generate green primary color light after being irradiated by laser, and the blue subregion can generate blue primary color light after being irradiated by laser. In practical applications, the above-mentioned functions can be realized by arranging different wavelength conversion materials on at least two color sections of the color wheel.

It should be noted that, in the embodiment of the present application, at least two subsections of the color wheel may be divided into two types of subsections, and the two types of subsections may be a first subsection and a second subsection. Wherein, the first partition is the corresponding angle (the angle corresponding to the first partition can be understood as the total angle of the same partition on the color wheel) compared with the first target angle (it can be understood as the angle of the same partition on the color wheel in the prior art) total angle) increased partitions. Optionally, if the current partition corresponding to the laser light source is the first partition, compared with the luminous flux of the laser light source corresponding to the partition corresponding to the color wheel in the prior art, in order to achieve white balance, specifically, the power supply control module can be used according to the entire The control signal sent by the control module of the projection device modulates the current of the laser light source in real time, thereby changing the luminous flux of the laser light source in the corresponding section, that is, reducing the luminous flux of the laser light source. Optionally, the second section is the corresponding angle ( The angle corresponding to the second partition can be understood as the total angle of the same partition on the color wheel) compared with the second target angle (which can be understood as the total angle of the same partition on the color wheel in the prior art) is reduced, optional Yes, if the current division corresponding to the laser light source is the second division, compared with the luminous flux of the laser light source corresponding to the division corresponding to the color wheel in the prior art, in order to achieve white balance, the luminous flux of the laser light source can be increased. Similarly, the current of the laser light source can be modulated in real time through the power control module according to the control signal sent by the control module of the entire projection equipment, and then the luminous flux of the laser light source in the corresponding section can be changed, that is, the luminous flux of the laser light source can be increased, and the color of the laser light source can be increased. The angle size of the first partition and the second partition on the wheel can be set, so that the proportion of different partitions on the color wheel can be more balanced than the original proportion of the color wheel in the prior art.

The power control module may be specifically configured to acquire the luminous flux ratio corresponding to each partition irradiated by the laser light source, and then acquire the pulse modulation parameters corresponding to the partition irradiated by the current laser light source based on the luminous flux ratio. Optionally, in this embodiment, the manner of acquiring the pulse modulation parameters corresponding to the partitions illuminated by the current laser light source based on the ratio of the luminous flux may not be limited. Wherein, if the color wheel is a yellow-blue color wheel, the luminous flux ratio can be the ratio between the luminous flux irradiated by the laser light source in the blue subregion and the luminous flux irradiated by the laser light source in the yellow subregion. If the color wheel is a red, green and blue wheel (which can also be understood as an RGB color wheel), the luminous flux ratio can be the luminous flux irradiated by the laser light source in the red partition, the luminous flux irradiated by the laser light source in the green partition, and the luminous flux irradiated by the laser light source in the blue partition The ratio between the luminous fluxes of the partitions.

Optionally, the light source proposed in the embodiments of the present application may be applied to a single-chip or two-chip DLP (Digital Light Processing, digital light processing) projection display system, and the projection display system may include a cinema machine, an educational machine, a laser TV, and Projection equipment such as engineering machines. Among them, the color wheel is usually used in the dual-chip DLP projection display system to complete the time domain separation of colors. The principle of dividing different color areas in the color wheel may be 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 color wheel.

Optionally, in the single-chip DLP projection display system, assuming that the luminous fluxes of the RGB(Y) monochromatic lights when their respective time duty cycles are 100% are Φ _R , Φ _G , Φ _B (, Φ _Y ), respectively, use According to the additive color mixing principle, it can be obtained that when the RGB(Y) primary color light is mixed into the specified white light, the lumen ratio is ρ _R , ρ _G , ρ _B (, ρ _Y ) respectively. _{Then the total angle θ R} , θ _G , θ _B (, θ _Y ) of each primary color light on the color wheel can be calculated using the following formula:

Optionally, in the dual-chip DLP projection display system, the time domain separation of blue light and yellow light can be realized by using a spectroscopic color wheel, or the blue light and yellow light can be emitted directly by a fluorescent color wheel, and then the red and green light splitting film can be used to separate the blue light and yellow light. The red and green light are split into two spatial light modulators 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 angle θ B} , θ _Y of each primary color light on the BY color wheel (which can also be understood as the yellow-blue color wheel described later) can be calculated using the following formula (where t _R , t _G , t _B are the synthetic white light respectively. time to display RGB color light):

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:

As one way, as shown in FIG. 2 , if the projection display system is a two-chip DLP projection display system, the blue laser 202 can be sequentially divided into transmitted light and reflected light by the color wheel 301 , and the reflected light is irradiated on the fluorescent color wheel 402 The yellow fluorescence can be excited, and the yellow fluorescence is collected by the light collecting device 302 and then incident on the prism 305. The yellow fluorescence can be divided into red primary color light and green primary color light by the red-transmitting and anti-green film on the prism 305; the transmitted light is directly used as the blue primary color photosynthesis. In the incoming light path, the red primary color light and the green primary color light are regulated by the same spatial light modulator 306 , and the green primary color light is regulated by the spatial light modulator 307 .

As an implementation manner, a blue laser with a wavelength of 455 nm can be used as the blue primary color light, and the fluorescence excited by it is the red and green primary color light. Optionally, if the fluorescence generated by exciting a typical yellow powder 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 can be obtained as R: (0.649 , 0.350), G: (0.325, 0.630), B: (0.151, 0.023). Optionally, when the recommended white point with coordinates (0.313, 0.329) is generated from the combination of RGB primary colors with color coordinates of R: (0.649, 0.350), G: (0.325, 0.630), and B: (0.151, 0.023) respectively , it can be obtained that the ratios of the brightness of the RGB primary color light 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 fluorescence, there is a proportional relationship between the luminous flux of the blue laser and the excited red and green fluorescence. Optionally, it is assumed that the blue laser with a luminous flux of 1lm can be excited to produce 0.78lm red Fluorescence and 3.82lm green fluorescence.

In this way, please refer to FIG. 3 , which shows an example diagram of the distribution of blue laser current and color wheel timing in the prior art. Optionally, as shown in FIG. 3 , if the laser light source keeps a constant Exciting current (I), it can be obtained that the total angles of the translucent area 3011 and the inverse blue area 3012 on the color wheel (which can be understood as the aforementioned yellow-blue spectroscopic color wheel) 301 are transmissive (B) 37° and inverse (Y) 323° respectively. °, the translucent blue area 3011 refers to the blue area, and the anti-blue area 3012 refers to the yellow area. The blue laser reflected in the anti-blue area can be used to excite the yellow phosphors on the fluorescent color wheel to emit yellow light. The blue-transmitting area directly transmits the blue laser. The anti-blue area and the blue-transmitting area reflect the blue laser and transmit the blue laser. In order to change the direction of the light path of the blue laser, in this way, when the yellow-blue light splitting color wheel is divided into N segments (N is a positive integer), if the display bit depth is 8 bits, and the double-space light The minimum turn-on time of the modulator is 16us, then the total display time of a single primary color light in each frame needs to be greater than (2 ⁸ -1)×16us=4.08ms. If the blue primary color light with the lowest time duty cycle needs to achieve 8-bit grayscale , then the period of the yellow-blue spectroscopic color wheel (T in Figure 3) can be at least

In this way, the corresponding equivalent frame rate can be expressed as:

It can be seen that when the display bit depth is maintained, the corresponding display frame rate is lower.

As a way to improve the display frame rate, the proportion of each partition of the color wheel can be changed and relatively balanced, and in order to ensure the white balance, the luminous flux of the corresponding laser light source in the corresponding partition can be changed. The luminous flux is related to the optical power, and the optical power and current are Related, and further can realize the adjustment of the current of the corresponding partition of the corresponding laser light source.

Illustratively, please refer to FIG. 4 , which shows an example diagram of the distribution of blue laser current and color wheel timing in the present application. As shown in FIG. 4 , as an implementation manner, when the color wheel 301 (which can be understood as the aforementioned yellow-blue light-splitting color wheel) turns to the blue partition 3011, the luminous flux of the blue laser can be configured as Φ ₁ , and the yellow-blue light splitting can be configured as Φ 1 . When the color wheel turns to the yellow zone 3012, the luminous flux of the blue laser is configured as Φ ₂ .

In one embodiment, _{the ratio of Φ 1} and Φ ₂ can be configured as: Φ ₁ :Φ ₂ =1:8.67. In this way, the total angles of the transparent blue area and the anti-blue area on the color wheel 301 are 180° through (B) and 180° in reverse (Y), respectively. The segment ratio of partitions to yellow partitions can be 1:1. The yellow zone refers to the anti-blue zone, and the blue zone refers to the blue-transmitting zone. The blue laser reflected by the anti-blue zone can be used to excite the yellow phosphor on the fluorescent color wheel to emit yellow light, and the blue-transmitting zone directly transmits blue light. The anti-blue area and the blue-transmitting area reflect the blue laser and transmit the blue laser, which are used to change the direction of the light path of the blue laser. Optionally, the time-averaged power can be made below the limit power of the power control module.

In this case, when the yellow-blue light splitting color wheel is divided into N segments (N is a positive integer), if the display bit depth is 8 bits, and the shortest turn-on time of the double-chip spatial light modulator is 16us, Then the total display time of a single primary color light in each frame of pictures needs to be greater than (2 ⁸ -1)×16us=4.08ms. If the blue primary color light with the lowest time duty ratio needs to achieve 8-bit grayscale, the cycle of the yellow-blue color wheel T is at least

In this way, the corresponding frame rate can be expressed as:

It can be understood that when the total angle corresponding to the blue partition 3011 changes from 3011 shown in FIG. 3 to 3011 shown in FIG. 4 , the total angle corresponding to the partition increases. In this way, changing the corresponding The ratio between the luminous flux of the blue laser and the luminous flux of the yellow-blue color wheel irradiated by the laser light source and the luminous flux of the blue laser corresponding to the yellow partition is 1:8.67. In this embodiment, the total angle of penetration (B) 180° corresponding to the blue sub-area is larger than the aforementioned penetration (B) 37°, and the total angle corresponding to the yellow sub-area is opposite (Y) 180° relative to the aforementioned inverse (Y) ) 323° becomes smaller. The obtained display frame rate is 122.5H _Z > 25H _Z , that is, the display frame rate is improved. In other implementations, for the dual-chip DLP projection display system, the yellow-blue light splitting color wheel may not be set, but the fluorescent color wheel is directly used, and the yellow and blue partitions are set. The yellow partition is set with yellow phosphor powder, and the blue partition transmits blue light. Or reflect blue light, by configuring the ratio of the luminous flux of the blue laser corresponding to the blue partition irradiated by the laser light source and the luminous flux of the blue laser corresponding to the color wheel irradiated by the laser light source to the yellow partition is still 1:8.67, then the blue partition and the yellow The angles of the partitions are 180° and 180°. According to the above calculated frame rate results and the described principles, the corresponding frame rate is also increased, and this implementation also increases the display frame rate. In another embodiment, _{the ratio of Φ 1} and Φ ₂ can also be configured as: Φ ₁ :Φ ₂ =1:4. In this case, the total angle of the transparent blue area and the anti-blue area on the yellow-blue color wheel can be 114° through (B) and 246° reverse (Y), respectively. In this way, the yellow-blue color wheel The ratio of the blue partition to the yellow partition can be 0.46:1. When the yellow-blue spectroscopic color wheel is divided into N segments of transflective and transflective, if the display bit depth is 8 bits, and the shortest turn-on time of the spatial light modulator is 16us, the total display time of a single primary color light in each frame of pictures needs to be greater than (2 ⁸ -1)×16us=4.08ms. If the blue primary color light with the lowest time duty ratio needs to achieve 8-bit grayscale, the yellow-blue light separation color wheel The period T can be at least as follows:

In this way, the corresponding frame rate can be expressed as:

In order to ensure the white balance, the ratio of the luminous flux of the blue laser corresponding to the yellow-blue light splitting color wheel irradiated by the laser light source to the blue partition is 1: 4. By reducing the luminous flux of the excitation current of the laser light source corresponding to the partition with the larger total angle of the segment, increasing the luminous flux of the excitation current of the laser light source corresponding to the partition with the smaller total angle of the segment. In this embodiment, the total angle of penetration (B) 114° corresponding to the blue partition is larger than the aforementioned penetration (B) 37°, and the total angle corresponding to the yellow partition is reversed (Y) 246° relative to the aforementioned reverse (Y) ) 323° becomes smaller, and the resulting display frame rate is 77.6H _Z >25H _Z , which can improve the display frame rate. In other implementations, for the dual-chip DLP projection display system, the yellow-blue light splitting color wheel may not be set, but the fluorescent color wheel is directly used, and the yellow and blue partitions are set. The yellow partition is set with yellow phosphor powder, and the blue partition transmits blue light. Or reflect blue light, by configuring the ratio of the luminous flux of the blue laser corresponding to the blue partition irradiated by the laser light source and the luminous flux of the blue laser corresponding to the color wheel irradiated by the laser light source to the yellow partition is still 1:4, and then the blue partition and yellow The angles of the partitions are 114° and 246°. According to the frame rate results calculated above and the described principles, the corresponding frame rate is also increased, and this implementation also increases the display frame rate.

As another implementation, when the yellow-blue light-splitting color wheel is divided into N segments (N is a positive integer), if the display bit depth is increased from 8 bits to 10 bits, the shortest turn-on time of the spatial light modulator is 16us, the total display time of a single primary color light in each frame of pictures needs to be greater than (2 ¹⁰ -1)×16us=16.39ms, if the blue primary color light with the lowest time duty ratio needs to achieve 10-bit grayscale, then the yellow-blue light splitting color wheel The period T can be at least as follows:

In this way, the corresponding frame rate can be expressed as:

It can be seen that the ratio of the luminous flux of the blue laser corresponding to the yellow-blue spectroscopic color wheel irradiated by the laser light source to the blue partition is 1:8.67 , on this basis, the number of bits of the display bit depth is increased, and the obtained display frame rate is 30.5H _Z > 25H _Z , which realizes that by changing the proportion of each partition of the color wheel and relatively balanced, the display frame rate is improved, and in order to To ensure the white balance, change the luminous flux of the corresponding laser light source in the corresponding partition. The luminous flux is related to the optical power, and the optical power is related to the current, so as to adjust the current of the corresponding laser light source corresponding to the partition.

As another way, if the projection display system is a single-chip DLP projection display system, a blue laser with a wavelength of 455 nm can be used as the blue primary color light, and the fluorescence excited by it is the red and green primary color light. If the fluorescence generated by exciting a typical green powder is separated at 590nm, the short-band part is green primary color light, and the green powder is a phosphor with a green light band in the emission fluorescence spectrum, or it can be a "yellow powder" with a green light band. , excite a typical red powder to obtain the long-band part of the wavelength greater than 590nm, which is the red primary color light. The red powder is a phosphor that contains the red light band in the emission fluorescence spectrum, or it can be a "yellow powder" containing the red light band, then RGB can be obtained. The color coordinates of the primary color light are R: (0.649, 0.350), G: (0.325, 0.630), and B: (0.151, 0.023). Optionally, when the white point is recommended by the coordinates (0.313, 0.329) generated by the combination of RGB primary color light with color coordinates of R: (0.649, 0.350), G: (0.325, 0.630), and B: (0.151, 0.023), It can be obtained that the luminance ratios of the three primary colors are R: 19.6%, G: 77.5%, and B: 2.9%, respectively.

Since both green primary color light and red primary color light are generated by blue laser excitation fluorescence, there is a proportional relationship between the luminous flux of the blue laser and the excited red and green fluorescence. Optionally, it is assumed that a blue laser with a luminous flux of 1lm can be excited to produce 0.78lm red Fluorescence or 6.06lm green fluorescence, in this way, the total angles corresponding to RGB on the red, green and blue wheels can be obtained as R: 222°, G: 113°, B: 25°, respectively. When the red, green and blue wheels are divided into N segments of RGB (N is a positive integer), if the display bit depth is 8 bits, and the minimum turn-on time of the spatial light modulator is 16us, the total display time of single primary color light in each frame of picture It needs to be greater than (2 ⁸ -1)×16us=4.08ms. If the blue primary color light with the lowest time duty cycle needs to achieve 8-bit grayscale, the period of the red, green and blue wheels can be at least

In this way, the corresponding frame rate can be expressed as:

As a way to improve the display frame rate, the proportion of each partition of the color wheel can be changed and relatively balanced, and in order to ensure the white balance, the luminous flux of the corresponding laser light source of the corresponding partition can be changed. The luminous flux is related to the optical power, while the optical power and current Related, and further can realize the adjustment of the current of the corresponding partition of the corresponding laser light source.

As an implementation manner, please refer to FIG. 5 , which shows a front view of the red, green and blue wheels provided in this embodiment. As shown in FIG. 5 , the color wheel 301 is a red, green, and blue wheel, which is a fluorescent color wheel, and includes a red subsection 3013 , a green subsection 3014 and a blue subsection 3015 (the location of the specific subsections may not be limited). Alternatively, rotation may be in the red, green and blue to red when the partition 3013 is configured as a blue laser light flux Φ _1, and the red, green and blue to green rotation when the partition 3014 is configured as a blue laser light flux Φ _2, red _{The luminous flux of the blue laser is configured as Φ 3} when the green-blue wheel goes to the blue zone 3015 . Other structural parts of the projection display system are set as required.

In one embodiment, _{the ratio of Φ 1} , Φ ₂ and Φ ₃ can be configured as: Φ ₁ :Φ ₂ :Φ ₃ =8.67:4.41:1. In this way, the corresponding total angles on the RGB color wheel can be R: 120°, G: 120°, B: 120° respectively. In this way, if the color wheel in this embodiment is red, green and blue A color wheel (RGB color wheel), the ratio of the red subregion, the green subregion and the blue subregion of the color wheel can be 1:1:1. When the RGB color wheel is divided into N segments of RGB (N is a positive integer), if the display bit depth is 8 bits, and the minimum turn-on time of the spatial light modulator is 16us, the total time required to display a single primary color light in each frame of pictures Greater than (2 ⁸ -1)×16us=4.08ms, if the blue primary color light with the lowest time duty ratio needs to achieve 8-bit grayscale, the period of the RGB color wheel is at least

In this way, the frame rate corresponding to the light source can be expressed as:

It can be seen that, in order to ensure the white balance, by adjusting the luminous flux of the blue laser corresponding to the red, green and blue irradiated by the laser light source to the red partition and the luminous flux of the blue laser corresponding to the red, green and blue irradiated by the laser light source to the green partition, and the The ratio of the luminous flux of the red, green and blue irradiated by the laser light source to the blue laser corresponding to the blue partition is Φ ₁ :Φ ₂ :Φ ₃ =8.67:4.41:1, wherein the total angle corresponding to the red partition is 120° relative to the aforementioned 222° becomes smaller, the total angle 120° corresponding to the green partition becomes larger than the aforementioned 113°, and the total angle 120° corresponding to the blue partition becomes larger than the aforementioned 25°, resulting in a display frame rate of 81.7H _Z > 17H _Z, increase the display frame rate.

In another embodiment, in order to reduce the modulation frequency of the illumination light, on the basis of the above-mentioned embodiment, when the RGB color wheel is shifted to the red partition and the green partition, the luminous flux of the blue laser can be configured as Φ ₁ , and the luminous flux of the blue laser can be configured to be Φ 1 In the color division, the luminous flux of the blue laser is configured as Φ ₃ , in this way, _{the ratio of Φ 1} and Φ ₃ can be configured as: Φ ₁ :Φ ₃ =4.41:1, then, the red, green and blue irradiated by the laser light source The luminous flux of the blue laser corresponding to the color wheel turning to the red zone, the luminous flux of the blue laser corresponding to the red, green and blue irradiated by the laser light source, and the luminous flux of the blue laser corresponding to the red, green and blue turning to the blue zone irradiated by the laser light source. The ratio of luminous flux is 4.41:4.41:1. In this case, the corresponding total angles on the RGB color wheel can be R: 178°, G: 91°, B: 91°. In this way, if the color wheel is the red, green and blue wheel (RGB color wheel) ), the ratio of the red, green and blue sections of the color wheel can be 1.96:1:1. When the color wheel is divided into N segments of RGB (N is a positive integer), if the display bit depth is 8 bits, and the minimum turn-on time of the spatial light modulator is 16us, the total display time of a single primary color light in each frame of pictures needs to be greater than (2 ⁸ -1)×16us=4.08ms, if the blue primary color light with the lowest time duty ratio needs to achieve 8-bit grayscale, the period of the red, green and blue wheels can be at least

In this way, the corresponding frame rate can be expressed as:

It can be seen that, in order to ensure the white balance, by adjusting the luminous flux of the blue laser corresponding to the red, green and blue irradiated by the laser light source to the red partition and the luminous flux of the blue laser corresponding to the red, green and blue irradiated by the laser light source to the green partition, and the The ratio of the luminous flux of the red, green and blue irradiated by the laser light source to the blue laser corresponding to the blue partition is 4.41:4.41:1. Among them, the total angle corresponding to the red partition of 178° is smaller than the aforementioned 222°, the total angle corresponding to the green partition of 91° is smaller than the aforementioned 113°, and the total angle corresponding to the blue partition is 91° relative to the aforementioned 25° When the ° becomes larger, the obtained display frame rate is 62.0H _Z >17H _Z , which increases the display frame rate.

In the light source provided by the embodiment of the present application, by setting the ratio of the divisions of the color wheel to a relatively balanced preset ratio, the primary color lights corresponding to different divisions can be synthesized to meet the preset color balance standard, and each primary color can be displayed in white field. The time duty cycle of the light can be more balanced, so that the display frame rate can be increased while maintaining the display effect.

Optionally, this embodiment further provides a projection apparatus, and the projection apparatus may include the light source in the foregoing embodiments. The adjustment principle and working process of the light source of the projection device can be referred to the descriptions in the foregoing embodiments, which will not be repeated here.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand: it can still be Modifications are made to the technical solutions described in the foregoing embodiments, or some technical features thereof are equivalently replaced; and these modifications or replacements do not drive the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

A light source, characterized in that it includes:

laser light source;

A color wheel, the color wheel includes at least two sub-regions, different sub-regions are irradiated by the laser light source to generate different primary color light or different sub-regions are used to change the light path direction of the laser light source, and the proportion of the sub-regions is relatively Balanced and set to a preset ratio to increase the display frame rate.
The light source according to claim 1, wherein the different partitions are correspondingly configured with different luminous flux ratios.
The light source according to claim 2, wherein the at least two sub-regions include a yellow sub-region and a blue sub-region, and the luminous flux ratio is the luminous flux of the laser light source irradiating the blue sub-region and the The ratio between the luminous fluxes of the light source illuminating the yellow zone.
The light source according to claim 3, wherein the ratio is 1:8.67.
The light source according to claim 3, wherein the ratio is 1:4.
The light source according to claim 3, wherein the ratio of the blue sub-region to the yellow sub-region is 1:1.
The light source according to claim 3, wherein the ratio of the blue sub-region to the yellow sub-region is 0.46:1.
The light source according to claim 2, wherein the at least two partitions include a red partition, a green partition and a blue partition, and the luminous flux ratio is the luminous flux irradiated by the laser light source on the red partition and the The ratio between the luminous flux irradiated by the laser light source on the green partition and the luminous flux irradiated by the laser light source on the blue partition.
The light source according to claim 8, wherein the ratio is 8.67:4.41:1.
The light source according to claim 8, wherein the ratio is 4.41:4.41:1.
The light source according to claim 8, wherein the ratio of the red sub-regions, the green sub-regions and the blue sub-regions is 1:1:1.
The light source according to claim 8, wherein the ratio of the red subsection, the green subsection and the blue subsection is 1.96:1:1.
The light source according to any one of claims 1-12, wherein the laser light source is a blue laser.
A projection device, characterized in that, the projection device adopts the light source according to any one of claims 1-13.