Optomechanical illumination system

Abstract

This application provides an optomechanical illumination system, including a laser source, a first spatial light modulator, a second spatial light modulator, a first beam splitter and combiner, and a second beam splitter and combiner. The laser source emits three primary colors of light, including a first color, a second color, and a third color. The third color has a higher optical power than the first color and the second color, and includes first polarized light and second polarized light. The first beam splitter and combiner guides the first polarized light to the first spatial light modulator for modulation, guides the second polarized light to the second spatial light modulator for modulation, and also guides the first and second colors of light to either the first or second spatial light modulator for modulation. The second beam splitter and combiner combines the modulated light beams before emission. The optomechanical illumination system provided in this application achieves optical power balance across a wide color gamut, while also balancing thermal load and increasing the output light of the projection.

Description

Technical Field

[0001] This application relates to the field of projection technology, specifically to an optomechanical lighting system. Background Technology

[0002] Commonly used spatial light modulators are broadly classified into two categories: transmissive and reflective. Transmissive spatial light modulators, such as LCDs (Liquid Crystal Displays), utilize the photoelectric effect of liquid crystal molecules. An external electric field alters the refractive properties of the liquid crystal molecules on the LCD panel, thereby achieving grayscale levels. Reflective spatial light modulators mainly fall into two categories: DMDs (Digital Micromirror Devices) and LCOSs (Liquid Crystal on Silicon). A DMD can be described as a semiconductor switch, consisting of 500,000 to 1,300,000 micromirrors aggregated on a CMOS (Complementary Metal Oxide Semiconductor) silicon substrate. Each micromirror represents a pixel, and the grayscale level of the pixel is controlled by the flipping sequence of the micromirrors. Normal micromirror flipping is divided into crossover time and switch time, representing the state transition time of the micromirror and the minimum interval between two consecutive state transitions, respectively. Figure 1 shows the flipping timing of DMD lenses in related technologies. In a single DMD system, the timing time interval shown in Figure 1 can achieve 8-bit grayscale for RGB three colors. However, in a dual DMD system or a triple DMD system, more image grayscale can be achieved.

[0003] The uniform illumination incident on a spatial light modulator is modulated to form an image. High brightness of the image can be achieved by increasing the light power incident on the spatial light modulator per unit time. However, the thermal load from the illumination limits further increases in the light power on the spatial light modulator. For example, in a DMD, uniform illumination hitting a micromirror generates heat due to mirror reflection. Furthermore, to ensure full pixel coverage, some overfill is inevitable (laser projection systems typically reserve some energy of the light illuminating the projection chip to avoid dark bands; this energy extends beyond the chip's edge, and the ratio of the energy exceeding the chip's edge to the total light energy is called overfill. Theoretically, the light source's utilization is highest when it completely covers the projection chip, but in practice, some overfill is reserved. However, a larger overfill results in lower utilization of the light source used for imaging; too small an overfill leads to dark bands). This portion of light is almost entirely converted into heat.

[0004] Related technologies reduce the thermal load from illumination by improving the quality of the light spot incident on the spatial light modulator, reducing overfill, or designing structures that facilitate heat dissipation to ensure the heat dissipation capacity of the DMD. However, these methods are complex in structure and expensive.

[0005] For projection systems with multiple spatial light modulators, such as dual DMD projection systems, balancing the thermal load on each spatial light modulator is also a way to increase the optical power incident on the spatial light modulator per unit time. Figure 2 This is a schematic diagram of a dual-DMD projection system 100 in related technologies. In the dual-DMD projection system 100, on one hand, a first laser group 111 generates blue excitation light to excite a wavelength conversion device 120 to generate yellow fluorescence. This yellow fluorescence is then split by a beam splitter 130 to generate red and green light, which are distributed to the first DMD 141 and the second DMD 142, respectively. On the other hand, the second laser group 112 provides blue laser light to sequentially fill the gap in the first DMD 141, achieving thermal power balance of the dual spatial light modulator under specific color gamut requirements. However, the optical power of different colors of light varies greatly under different color gamuts. For example, in a laser-fluorescent light source, the wavelength range of green light is 490nm-580nm, and its optical efficiency is 509lm / W, while in a laser light source, the wavelength of green light is 525nm, and its optical efficiency reaches 541.8lm / W. Therefore, the optical efficiency of the three colors of light differs greatly under different color gamuts, and the optical power of the three colors of light required to synthesize white light will also differ. Due to the broad-spectrum characteristics of fluorescence, the dual-DMD projection system 100 has a narrower color gamut, making it difficult to adapt to different color gamut requirements. Furthermore, the dual-DMD projection system 100 cannot dynamically adjust the balancing light power. Summary of the Invention

[0006] The purpose of this application is to provide an optomechanical illumination system to solve the above-mentioned problems. The embodiments of this application achieve the above objective through the following technical solutions.

[0007] This application provides an optomechanical illumination system, including a light source module, a first spatial light modulator, a second spatial light modulator, a first light splitter and combiner, and a second light splitter and combiner. The light source module emits three primary colors of light, including a first color light, a second color light, and a third color light. The light power of the third color light is greater than the light power of the first color light and greater than the light power of the second color light. The third color light includes first polarized light and second polarized light. The first light splitter and combiner guides the first polarized light to the first spatial light modulator for modulation and guides the second polarized light to the second spatial light modulator for modulation. The first light splitter and combiner also guides the first color light to either the first or second spatial light modulator for modulation and guides the second color light to either the first or second spatial light modulator for modulation. The second light splitter and combiner combines the first color light, the second color light, the first polarized light, and the second polarized light modulated by the first and second spatial light modulators before emitting the combined light.

[0008] In one embodiment, the light source module is also used to adjust the ratio of the first polarized light to the second polarized light.

[0009] In one embodiment, the light source module includes a first laser, a second laser, a third laser, and a polarization converter. The first laser is used to emit a first color light; the second laser is used to emit a second color light; the third laser is used to emit a third color light; and the polarization converter is used to convert the polarization state of the third color light to obtain first polarized light and second polarized light, and to adjust the ratio between the first polarized light and the second polarized light.

[0010] In one embodiment, the light source module includes a first laser, a second laser, a first polarized laser, and a second polarized laser. The first laser is used to emit a first color of light; the second laser is used to emit a second color of light; the first polarized laser is used to emit first polarized light; and the second polarized laser emits second polarized light.

[0011] In one embodiment, the light source module further includes a polarizing reflector and a polarizing beam combiner; the polarizing reflector is used to guide the first polarized light to the polarizing beam combiner, or to guide the second polarized light to the polarizing beam combiner; the polarizing beam combiner is used to combine the first polarized light and the second polarized light to form a third color light.

[0012] In one embodiment, the first color light is red light, the second color light is blue light, the third color light is green light, the first polarized light is green P-polarized light, and the second polarized light is green S-polarized light; the first light splitter and combiner is used to guide the red light and green S-polarized light to the first spatial light modulator for modulation, and to guide the blue light and green P-polarized light to the second spatial light modulator for modulation.

[0013] In one embodiment, the optomechanical illumination system further includes a first dichroic filter and a second dichroic filter, wherein the first dichroic filter is disposed on the beam-splitting surface of the first beam splitter and beam combiner, and the second dichroic filter is disposed on the beam-splitting surface of the second beam splitter and beam combiner.

[0014] In one embodiment, the first color light is green light, the second color light is blue light, the third color light is red light, the first polarized light is red P-polarized light, and the second dipolarized light is red S-polarized light; the first light splitter and combiner is used to guide the green light, blue light, and red S-polarized light to the first spatial light modulator for modulation, and to guide the red P-polarized light to the second spatial light modulator for modulation.

[0015] In one embodiment, the optomechanical illumination system further includes a first polarizing bandpass filter and a second polarizing bandpass filter, wherein the first polarizing bandpass filter is disposed on the beam-splitting surface of the first beam splitter and beam combiner, and the second polarizing bandpass filter is disposed on the beam-splitting surface of the second beam splitter and beam combiner.

[0016] In one embodiment, the optomechanical illumination system further includes a reflecting lens, a light homogenizing device, and a relay lens group; the reflecting lens is used to guide the three primary colors of light emitted by the light source module to the light homogenizing device, the light homogenizing device is used to homogenize the three primary colors of light emitted by the reflecting lens, and the relay lens group is used to relay the three primary colors of light emitted by the light homogenizing device to the first light splitting and combining device.

[0017] Compared to existing technologies, the optomechanical illumination system provided in this application uses the three primary colors of light emitted by the light source module as projection light. By splitting the third color light with the highest optical power into first polarized light and second polarized light, the first light splitting and combining device can evenly distribute the first color light, second color light, first polarized light and second polarized light to two spatial light modulators for modulation. This achieves optical power balance of the dual spatial light modulators under a wide color gamut. While balancing the thermal load of the dual spatial light modulators, it also allows the dual spatial light modulators to work at full load under ideal conditions, increasing the light output of the projection and achieving high brightness of the image. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 is a timing diagram of the flipping of DMD lenses in related technologies.

[0020] Figure 2 This is a schematic diagram of the structure of a dual DMD projection system in related technologies.

[0021] Figure 3 It is a comparison image of images with different bit depths in related technologies.

[0022] Figure 4 It is a color time sequence diagram of single DMD and dual DMD in related technologies.

[0023] Figure 5 It is the CIE 1931 color gamut diagram in related technologies.

[0024] Figure 6 It is a coordinate graph of the visual effect function of different wavelengths of colored light in related technologies.

[0025] Figure 7 This is a schematic diagram of the structure of the optomechanical illumination system provided in the embodiments of this application.

[0026] Figure 8 This is a graph showing the relationship between the sum of blue and green laser power and the ratio of red laser power to the wavelength of red laser in related technologies.

[0027] Figure 9 yes Figure 7 The P-polarized gating spectrum of the dichroic filter provided in the illustrated embodiment.

[0028] Figure 10 yes Figure 7 The S-polarized gating spectrum of the dichroic filter provided in the illustrated embodiment.

[0029] Figure 11 yes Figure 7 The color timing diagram of the single DMD and optomechanical illumination system provided in the illustrated embodiment.

[0030] Figure 12 yes Figure 7 The diagram shows a structural schematic of an optomechanical illumination system provided in another embodiment of the shown example.

[0031] Figure 13 This is a schematic diagram of the structure of an optomechanical illumination system provided in another embodiment of this application.

[0032] Figure 14 These are the color coordinates of the three primary colors as specified in the Rec. 2020 color gamut in related technologies.

[0033] Figure 15 yes Figure 13 The polarization bandpass filter spectrum provided in the illustrated embodiment.

[0034] Figure 16 yes Figure 13 The color timing diagram of the single DMD and optomechanical illumination system provided in the illustrated embodiment.

[0035] Figure 17 yes Figure 13 The diagram shows a structural schematic of an optomechanical illumination system provided in another embodiment of the shown example. Detailed Implementation

[0036] To facilitate understanding of the embodiments of this application, a more comprehensive description of the embodiments of this application will be provided below with reference to the accompanying drawings. Preferred embodiments of this application are shown in the drawings. However, this application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of this application.

[0037] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the embodiments of this application is for the purpose of describing particular implementations only and is not intended to be limiting of this application.

[0038] To address the issue that dual spatial light modulator projection systems in related technologies struggle to meet the requirements of different color gamuts, the applicant has creatively proposed an optomechanical illumination system. This system uses three primary colors of light emitted from a light source module as projection light. When there are differences in the optical power of the three primary colors, a beam splitter and combiner can be used to split the light with the highest optical power and distribute it evenly with the other two colors to two spatial light modulators for modulation. This achieves optical power balance of the dual spatial light modulators across a wide color gamut. While balancing the thermal load of the dual spatial light modulators, it also allows the spatial light modulators to operate at full capacity under ideal conditions, increasing the light output of the projection and achieving high brightness of the image.

[0039] The dual spatial light modulator projection system provided in this application can be applied to cinema projectors, educational projectors, laser TVs, micro projectors, and engineering projectors, etc., and this application does not specifically limit it.

[0040] The following is a brief explanation of the technical terms used in the embodiments of this invention:

[0041] The bit depth represents the number of bits required to display the grayscale information of a pixel in a grayscale image. The larger the bit depth, the smaller the difference between adjacent grayscale values, and the closer the digital image is to a normal display. Figure 3 The image shown is a comparison of images with different bit depths in related technologies. It is evident that a higher bit depth significantly enhances the detail and richness of the image. Therefore, increasing bit depth is a crucial indicator in the display industry and a pursuit of future high-end displays.

[0042] Display bit depth represents the number of gray levels. For example, an 8-bit image means it has 2^30 gray levels. 8= 256 gray levels. Different gray levels can be achieved by adjusting the duty cycle of the spatial light modulator over time. For example, for a DMD, achieving white light in a certain color gamut requires... Figure 4 Please refer to the color timing diagrams for single DMD and dual DMD shown below. Figure 4 The idle intervals in the color timing diagram are spokes in the timing sequence, set to reduce color breakup (also known as "rainbow effect" or "color separation") in some laser phosphor projection systems. The spoke phenomenon refers to the situation where, when using a phosphor color wheel or filter wheel with multiple color schemes, light shines on the boundary between two colors, resulting in impure colors (e.g., when red and blue are simultaneously illuminated, both red and blue light are emitted, while red light is emitted as an outgoing emission). Current solutions involve not emitting light during that time period, resulting in a completely black segment when the entire image is sampled. From... Figure 4 It is known that, at the same frame rate, a dual spatial light modulator system, after proper light splitting, can provide a greater proportion of color time. Therefore, compared to a single spatial light modulator, the dual spatial light modulator provided in this application can increase the display bit depth of the image, improve intra-frame contrast, produce a brighter picture, and provide a better display effect. Furthermore, compared to other multi-spatial light modulator projection systems, such as three-spatial light modulator systems, the dual spatial light modulator projection system has a simpler overall structure, uses fewer components, and has a lower cost.

[0043] Figure 5 This refers to the CIE 1931 color gamut diagram in related technologies; please refer to [link / reference]. Figure 5 As shown, the color gamut of human vision can be referenced in the CIE 1931 color gamut diagram. Normally, projection or display images use RGB primary colors, and the corresponding colors can be output by configuring the proportions of these RGB primary colors. When the color coordinates of the RGB primary colors are different, the color gamut range covered by the monitor or projector will also be different. The edges of the CIE 1931 color gamut diagram are composed of monochromatic light with wavelengths continuously varying from 380nm to 780nm; the closer to the center, the wider the spectral lines become. The commonly used Rec.709 color gamut covers less than half of the overall color gamut, while the Rec.2020 color gamut, which uses monochromatic light as the RGB primary colors, covers nearly 90% of the overall color gamut.

[0044] Figure 6 This is a coordinate graph of the visual effect function of different wavelengths of light in related technologies. Please refer to [link / reference]. Figure 6 As shown, different wavelength ranges of colored light have different luminous efficacy. When considering the luminous efficacy of monochromatic light, the luminous flux of the monochromatic light is obtained by multiplying the luminous efficacy value at that wavelength by its optical power. If the colored light has a certain spectral line, it is necessary to integrate the product of the optical power spectral line and the luminous efficacy of the colored light, as shown in the following formula (1):

[0045] (1)

[0046] Based on the color coordinates of the three primary colors required for a specific color gamut, the lumen ratio of the corresponding RGB three primary colors constituting D65 white light can be calculated using formulas (2) and (3). .

[0047] (2)

[0048] (3)

[0049] In formulas (2) and (3), x and y are known color coordinates, and Y... i The lumen ratio to be solved can be obtained by formula (2) and formula (3).

[0050] The required optical power is calculated based on a specific color gamut. Generally, green light has high visual efficacy, therefore its corresponding optical power is relatively large, requiring spectral splitting. However, in certain color gamuts, red light has a higher proportion and its optical power is the highest; the optimal approach is to split the red light. In this case, if a dual spatial light modulator projection system 100 (see details...) is used... Figure 2 The technical solution of the above will inevitably result in uneven distribution of optical power on the dual spatial light modulator. The optomechanical illumination system provided in this application embodiment can dynamically adjust the beam splitting strategy for different color gamuts, such as splitting green light in some color gamuts or red light in some color gamuts, thereby achieving optical power balance of the dual spatial light modulator under different color gamuts.

[0051] Currently, there are relatively few methods for using beam splitting strategies to balance optical power in dual spatial light modulators. One related technology proposes a multi-primary-color dual-DMD laser projection display device. This device emits laser light through laser source modules I and II. Laser source module I includes a red laser source denoted as R. A Red laser source denoted as R B The green laser source is denoted as G. B Laser source module II includes a blue laser source, denoted as B. A Blue laser source denoted as B B The green laser source is denoted as G. A This multi-color dual-DMD laser projection display device uses a multi-color laser light source and a dual-DMD structure, which improves the color gamut coverage. However, no technical problem of unbalanced optical power output from the dual spatial light modulator was found.

[0052] In another related technology, a dual-DMD-based imaging system was proposed. This system uses a microprocessor to analyze the received current image and determine if saturation regions exist. If saturation regions are found, the microprocessor performs temporal-domain dimming on the first DMD. The microprocessor then analyzes the image acquired after temporal dimming to determine if saturation regions still exist. If saturation regions still exist, the microprocessor performs spatial-domain dimming on the second DMD. This combines temporal and spatial dimming using two DMDs, ensuring image quality and expanding the dynamic range. However, the core of this imaging system lies in achieving high dynamic range images with dual spatial light modulators, and no technical problem of power imbalance in dual spatial light modulators has been found. Furthermore, its application scenario is not within the scope of three-primary-color laser projection.

[0053] Figure 7 This is a schematic diagram of the optomechanical illumination system provided in the embodiments of this application. Please refer to it. Figure 7 As shown, the optomechanical illumination system 200 includes a light source module 210, a first spatial light modulator 221, a second spatial light modulator 222, a first light splitter and combiner 231, and a second light splitter and combiner 232.

[0054] The light source module 210 can be a laser light source, used to emit three primary colors of light, including a first color, a second color, and a third color. The light power of the third color is greater than that of the first color and also greater than that of the second color. The third color includes first polarized light and second polarized light. In some embodiments, the light source module 210 can also be an LED (Light Emitting Diode) light source, which can also emit three primary colors of light.

[0055] Among them, the three primary colors refer to the basic light that can be used to synthesize other colors of light. They can be monochromatic light, such as red, green and blue light commonly used in this field. The third color light is polarized light, which can be represented by the vector sum of S-polarized light and P-polarized light. The first polarized light can be one of P-polarized light and S-polarized light, and the second polarized light can be the other of P-polarized light and S-polarized light.

[0056] The first spatial light modulator 221 and the second spatial light modulator 222 can be DMD, LCOS, LCD or other devices that implement spatial light modulation.

[0057] The first light-splitting and combining device 231 is used to guide first polarized light to the first spatial light modulator 221 for modulation, and to guide second polarized light to the second spatial light modulator 222 for modulation. The first light-splitting and combining device 231 is also used to guide first color light to the first spatial light modulator 221 or the second spatial light modulator 222 for modulation, and to guide second color light to the first spatial light modulator 221 or the second spatial light modulator 222 for modulation.

[0058] The second light-splitting and light-combining device 232 is used to combine the first color light, the second color light, the first polarized light, and the second polarized light modulated by the first spatial light modulator 221 and the second spatial light modulator 222, and then emit them.

[0059] During implementation, the ratio between the first polarized light and the second polarized light can be preset according to the optical power ratio between the first color light, the second color light and the third color light. Since the first polarized light is guided to the first spatial light modulator 221 for modulation and the second polarized light is guided to the second spatial light modulator 222 for modulation, the first color light and the second color light can be selectively guided to the first spatial light modulator 221 or the second spatial light modulator 222 for modulation, so as to balance the optical power of the first spatial light modulator 221 and the second spatial light modulator 222.

[0060] For example, when the optical power difference between the first color light, the second color light, and the third color light is small, and the optical power of the first color light is greater than that of the second color light, the ratio between the first polarized light and the second polarized light can be preset so that the sum of the optical power of the first polarized light and the first color light is equal to or nearly equal to the sum of the optical power of the second polarized light and the second color light. In this case, the first polarized light and the first color light are guided to the first spatial light modulator 221 for modulation, and the second polarized light and the second color light are guided to the second spatial light modulator 222 for modulation, so as to achieve the optical power balance between the first spatial light modulator 221 and the second spatial light modulator 222.

[0061] When the optical power of the third color light is much greater than that of the first color light and the second color light, the ratio between the first polarized light and the second polarized light can be set so that the sum of the optical power of the first polarized light, the first color light and the second color light is equal to or nearly equal to the optical power of the second polarized light. At this time, the first polarized light, the first color light and the second color light are guided to the first spatial light modulator 221 for modulation, and the second polarized light is guided to the second spatial light modulator 222 for modulation, so as to achieve the optical power balance between the first spatial light modulator 221 and the second spatial light modulator 222.

[0062] In this embodiment, the light source module 210 is also used to adjust the ratio between the first polarized light and the second polarized light. Adjusting the ratio between the first polarized light and the second polarized light refers to adjusting the duty cycle between them, so that the optomechanical illumination system 200 can be flexibly applied to various color gamuts, achieving optical power balance between the first spatial light modulator 221 and the second spatial light modulator 222 under different color gamuts.

[0063] The optomechanical illumination system 200 uses tri-color light as the projection light. Because the color coordinates of monochromatic light are distributed along the boundaries of the color gamut, a wide color gamut can be achieved. It should be noted that a wide color gamut, such as the Rec. 2020 color gamut (see details...), is a different concept. Figure 5 The color gamut standard has very strict requirements, and the corresponding optical performance of the three primary colors is not high. Especially in the red band, due to the low electro-optical efficiency of red lasers and the need for temperature control, some tradeoffs are required to meet practical engineering needs.

[0064] Please combine them together Figure 6 and Figure 7 As shown, the luminous efficacy of red light with a wavelength of 630nm, which meets the Rec. 2020 color gamut standard, is not high. However, slightly offset red light, such as red light with a wavelength of 620nm, has a luminous efficacy that is more than 40% higher than that of red light with a wavelength of 630nm. Considering cost factors, using red lasers or red fluorescent light with higher luminous efficacy (e.g., with a wavelength of 620nm) without deviating too far from the high color gamut apex is a wise and effective choice. In such cases, the optical power of the three primary colors is often no longer dominated by red light (the optical power of red light is higher than the sum of the optical power of blue and green light).

[0065] Figure 8 This is a graph showing the relationship between the sum of blue and green laser power and the ratio of red laser power to the wavelength of red laser in related technologies. Please refer to it as well. Figure 7 and Figure 8 As shown, in the red light wavelength range of 610nm~630nm, when the wavelength of red light is less than 627nm, the sum of the optical power of blue and green light is greater than that of red light. Even if red light with a wavelength of 610nm is used, as can be seen from the CIE 1931 color gamut diagram, the reduction in its color gamut coverage is very limited. Therefore, lower wavelength red light with higher optical efficiency can be selected, and this choice also makes the sum of the optical power of blue and green light greater than that of red laser light.

[0066] As an example, the optomechanical illumination system 200 can split green light to achieve optical power balance of the dual spatial light modulator, making the technical solution of this application more universal. For example, when the wavelengths of the RGB three primary colors constituting D65 white light are selected as 620nm, 550nm and 455nm respectively, the optical power ratio of the RGB three primary colors is... In this case, the light power of green light is greater than that of red light, and also greater than that of blue light. The green light can be reasonably split by the first light splitting and combining device 231 to meet the requirement of balanced light power.

[0067] In this embodiment, the first color light is red, the second color light is blue, and the third color light is green. The first polarized light is green P-polarized light, and the second polarized light is green S-polarized light. That is, green light has the highest optical power and is polarized light, including green P-polarized light and green S-polarized light with adjustable ratios. The first light splitter and combiner 231 is used to guide the red light and green S-polarized light to the first spatial light modulator 221 for modulation, and to guide the blue light and green P-polarized light to the second spatial light modulator 222 for modulation. This allows for optical power balance of the two spatial light modulators within the color gamut where green light has the highest optical power.

[0068] In this embodiment, a dichroic filter can be used to split green light. The optomechanical illumination system 200 also includes a first dichroic filter 233 and a second dichroic filter 234. The first dichroic filter 233 is disposed on the beam-splitting surface of the first beam-splitting and beam-combining device 231, and the second dichroic filter 234 is disposed on the beam-splitting surface of the second beam-splitting and beam-combining device 232. The first dichroic filter 233 has a wavelength gated difference for green P-polarized light and green S-polarized light. Based on this characteristic, a green light wavelength that matches the first dichroic filter 233 can be selected, so that the first dichroic filter 233 can reflect red light and green S-polarized light to the first spatial light modulator 221 for modulation, and transmit blue light and green P-polarized light to the second spatial light modulator 222 for modulation.

[0069] Figure 9 and Figure 10 These are the gated spectra of P-polarized light and S-polarized light from the dichroic filters provided in this application embodiment. The first dichroic filter 233 and the second dichroic filter 234 can be employed with... Figure 9 and Figure 10 The dichroic filters shown in the spectrum have a cutoff wavelength of 550 nm for the first dichroic filter 233 and the second dichroic filter 234, and their gating thresholds have a gap of about 5 nm, which is suitable for adding green light with a wavelength of 550 nm.

[0070] When using 550nm green P-polarized light, the first dichroic filter 233 and the second dichroic filter 234 transmit the green P-polarized light. When using 550nm green S-polarized light, the first dichroic filter 233 and the second dichroic filter 234 reflect the green S-polarized light. Simultaneously, the first dichroic filter 233 and the second dichroic filter 234 highly transmit light below the cutoff wavelength and highly reflect light above the cutoff wavelength. Therefore, the first dichroic filter 233 can transmit blue light to the second spatial light modulator 222 and reflect red light to the first spatial light modulator 221. By adjusting the ratio between the first polarized light and the second polarized light, the first polarized light, the second polarized light, the first color light, and the second color light can be evenly distributed to the first spatial light modulator 221 and the second spatial light modulator 222 for modulation.

[0071] In one embodiment, the ratio between the first polarized light and the second polarized light can be adjusted by a polarization converter. In this embodiment, the light source module 210 can be a laser light source, and the light source module 210 includes a first laser 2111, a second laser 2112, a third laser 2113, and a polarization converter 2114.

[0072] The first laser 2111 is used to emit a first color light (e.g., red light), the second laser 2112 is used to emit a second color light (e.g., blue light), the third laser 2113 is used to emit a third color light (e.g., green light), and the polarization converter 2114 is used to convert the polarization state of the third color light to obtain a first polarized light (e.g., green P-polarized light) and a second polarized light (e.g., green S-polarized light), and to adjust the ratio between the first polarized light and the second polarized light.

[0073] The polarization converter 2114, also known as a PCS (polarization conversion system), can be composed of a PBS (Polarized Beam Splitter) array and a half-wave plate. Taking green light as the third color as an example, the green light passes through the PBS array to obtain green S-polarized light and green P-polarized light. The half-wave plate is placed on the exit surface of the green S-polarized light, which can convert the green S-polarized light into green P-polarized light. The ratio between the green S-polarized light and the green P-polarized light can be adjusted.

[0074] It should be noted that the first dichroic filter 233, the second dichroic filter 234 and the wavelength of green light are compatible. When the third color light is red light or blue light or green light of some other wavelengths, those skilled in the art can choose other dichroic filters, polarizing bandpass filters or other beam splitting components that can meet the requirements, as long as they can achieve a balanced distribution of the three primary colors and achieve the optical power balance of the dual spatial light modulator.

[0075] Figure 11 This is a color timing diagram of a single DMD and optomechanical illumination system provided in an embodiment of this application. In some implementations, the duty cycle between green P-polarized light and green S-polarized light can be controlled to be 0.74:0.26. This allows the first spatial light modulator 221 to distribute red light and green light (i.e., green S-polarized light) with a power ratio of 0.26, and the second spatial light modulator 222 to distribute blue light and green light (i.e., green P-polarized light) with a power ratio of 0.74. In this color gamut (where the power of green light is greater than that of red light, and the power of green light is greater than that of blue light), the optical power balance of the dual spatial light modulators can be achieved.

[0076] Please refer to Figure 7 In this embodiment, the light source module 210 may further include three collimating lenses 2115. The three collimating lenses 2115 are respectively disposed in the output optical paths of the first laser 2111, the second laser 2112 and the third laser 2113, and are used to collimate the first color light, the second color light and the third color light before emission. Compared with before collimation, the divergence angle of the collimated beam is greatly compressed, thereby reducing the loss of the beam during propagation.

[0077] The optomechanical illumination system 200 also includes a reflecting lens 251, a light homogenizing device 252, and a relay lens group 253. The reflecting lens 251 is used to guide the three primary colors of light emitted by the light source module 210 to the light homogenizing device 252, the light homogenizing device 252 is used to homogenize the three primary colors of light emitted by the reflecting lens 251, and the relay lens group 253 is used to relay the three primary colors of light emitted by the light homogenizing device 252 to the first light splitting and combining device 231.

[0078] The reflecting lens 251 is used to change the optical path of the three primary colors of light, so that all three primary colors of light can be incident on the homogenizing device 252 for homogenization. The reflecting lens 251 may include a first reflecting sub-lens 2511 and a second reflecting sub-lens 2512. The first reflecting sub-lens 2511 is used to reflect blue light to the homogenizing device 252 and transmit red light to the homogenizing device 252. The second reflecting sub-lens 2512 is used to reflect green light to the homogenizing device 252 and transmit red and blue light to the homogenizing device 252, ensuring that all three primary colors of light can be incident on the homogenizing device 252. It should be noted that the embodiments of this application do not limit the number and type of optical elements included in the reflecting lens 251 for changing the optical path. All optical path conversion components used to receive the three primary colors of light and transmit the three primary colors of light to the homogenizing device 252 are within the protection scope of this application.

[0079] The light homogenizer 252 can homogenize the three primary colors of light, thereby avoiding problems such as excessive local impact causing burns and uneven brightness in the output image. The light homogenizer 252 can be any one of a light bar, a compound eye lens, or a light cone.

[0080] The relay lens group 253 is used to collect and converge the three primary color light emitted by the light homogenizing device 252 and then provide it to the first light splitting and combining device 231. The relay lens group 253 can be formed by a combination of multiple collecting lenses, such as convex lenses and concave lenses.

[0081] The optomechanical illumination system 200 also includes a first total internal reflection prism 261 and a second total internal reflection prism 262. The first total internal reflection prism 261 reflects the light beam emitted by the first light splitter / combiner 231 to the first spatial light modulator 221 for modulation, and then emits it to the second light splitter / combiner 232. The second total internal reflection prism 262 reflects the light beam emitted by the first light splitter / combiner 231 to the second spatial light modulator 222 for modulation, and then emits it to the second light splitter / combiner 232.

[0082] The first total internal reflection prism 261 and the second total internal reflection prism 262 can be composed of two triangular prisms. When light is incident on the first total internal reflection prism 261 and the second total internal reflection prism 262, total internal reflection occurs, thereby allowing more light to enter the first spatial light modulator 221 and the second spatial light modulator 222, which can improve the light collection capability of the optomechanical illumination system 200.

[0083] The optomechanical illumination system 200 also includes a lens 263, which is used to receive the combined light emitted from the second beam splitter and combiner 232 to ultimately form an image.

[0084] Figure 12 This is a schematic diagram of the structure of an optomechanical illumination system provided in another embodiment of this application. Please refer to [link / reference]. Figure 12 As shown, in another embodiment, the ratio between the first polarized light and the second polarized light can be adjusted by laser modules with different polarization states.

[0085] In this embodiment, the light source module 210 can be a laser light source, and the light source module 210 includes a first laser 2121, a second laser 2122, a first polarized laser 2123, and a second polarized laser 2124.

[0086] The first laser 2121 is used to emit a first color light (e.g., red light), the second laser 2122 is used to emit a second color light (e.g., blue light), the first polarized laser 2123 is used to emit a first polarized light (e.g., green P-polarized light), and the second polarized laser 2124 is used to emit a second polarized light (e.g., green S-polarized light). The ratio between the first polarized light and the second polarized light can be adjusted by controlling the duty cycle of the first polarized laser 2123 and the second polarized laser 2124.

[0087] In this embodiment, the light source module 210 further includes a polarizing reflector 2125 and a polarizing beam combiner 2126. The polarizing reflector 2125 guides first polarized light to the polarizing beam combiner 2126, or guides second polarized light to the polarizing beam combiner 2126. The polarizing beam combiner 2126 combines the first and second polarized light to form a third color light. As an example, the polarizing beam combiner 2126 is disposed in the optical path of the first polarized laser 2123, and the polarizing reflector 2125 is disposed in the optical path of the second polarized laser 2124. The polarizing reflector 2125 guides the second polarized light to the polarizing beam combiner 2126.

[0088] The polarizing mirror 2125 is used to change the optical path of the first polarized light or the second polarized light, so that the first polarized light and the second polarized light can be incident on the polarizing light combining device 2126 for light combining. The polarizing mirror 2125 can be a plane mirror or a curved surface mirror, which can be set according to actual needs.

[0089] The polarized light combining device 2126 is provided with a third dichroic filter 2128. The third dichroic filter 2128 can be a dichroic filter that is the same as the first dichroic filter 233, so that the third color light formed by combining the first polarized light and the second polarized light by the third dichroic filter 2128 can be split by the first dichroic filter 233 to form the first polarized light and the second polarized light.

[0090] It should be noted that the first polarized light emitted by the first polarized laser 2123 and the second polarized light emitted by the second polarized laser 2124 can be directly incident on the homogenizing device 252 for beam combining, or they can be combined by the polarized light combining device 2126 and then incident on the homogenizing device 252. The specific form is not limited.

[0091] In this embodiment, the light source module 210 further includes four collimating lenses 2127. The four collimating lenses 2127 are respectively disposed on the output light paths of the first laser 2121, the second laser 2122, the first polarized laser 2123, and the second polarized laser 2124, and are used to collimate the first color light, the second color light, the first polarized light, and the second polarized light before emitting them to form a collimated beam.

[0092] The optomechanical illumination system 200 provided in this application embodiment can set the ratio between green P-polarized light and green S-polarized light through a polarization converter 2114 or a first polarization laser 2123 and a second polarization laser 2124 with different polarization states. A dichroic filter is set in the first light splitter and combiner 231 to reflect red light and green S-polarized light to the first spatial light modulator 221 for modulation, and transmit blue light and green P-polarized light to the second spatial light modulator 222 for modulation. The optical power balance of the dual spatial light modulators can be achieved in a color gamut where the optical power of green light is greater than that of red light and blue light.

[0093] Figure 13 This is a schematic diagram of the structure of an optomechanical illumination system provided in another embodiment of this application. Please refer to [link / reference]. Figure 13 As shown, the optomechanical illumination system 300 provided in this embodiment can also achieve optical power balance of the dual spatial light modulator in a color gamut where the optical power of red light is greater than that of green and blue light (e.g., the Rec. 2020 color gamut).

[0094] In this embodiment, the first color light is green, the second color light is blue, the third color light is red, the first polarized light is red P-polarized light, and the second polarized light is red S-polarized light. That is, red light has the highest optical power, and red light is polarized light, including red P-polarized light and red S-polarized light with adjustable ratios.

[0095] In some high-end display scenarios, the Rec. 2020 color gamut is a necessity. According to the ITU-R Recommendation BT.2020 standard, the Rec. 2020 color gamut uses the RGB primary color coordinates as follows: Figure 14 As shown.

[0096] As can be seen from the CIE 1931 color gamut diagram, the three primary colors of the Rec. 2020 color gamut are monochromatic light. In order to achieve the Rec. 2020 color gamut standard, we consider using a laser light source as the three primary color light source, so that the optomechanical illumination system 200 can achieve the optical power balance of the dual spatial light modulator under the Rec. 2020 color gamut.

[0097] According to formulas (2) and (3) and Figure 6 The luminous power output of the RGB three primary colors corresponding to the Rec. 2020 color gamut can be calculated as follows: The white light corresponding to this optical power output is D65. It can be observed that within the Rec. 2020 color gamut, red light dominates in power, meaning its power is greater than that of green light, and also greater than that of blue light. In this situation, the first embodiment's method of splitting green light cannot achieve power balance in the dual spatial light modulator. For the Rec. 2020 color gamut, red light can be split.

[0098] The optomechanical illumination system 300 converts red light into a polarization state and sets the ratio between red P-polarized light and red S-polarized light. Then, through the first light splitting and combining device 331, green light, blue light, and red S-polarized light can be reflected to the first spatial light modulator 321 for modulation, and red P-polarized light can be transmitted to the second spatial light modulator 322 for modulation. This allows for the achievement of optical power balance between the two spatial light modulators within the Rec. 2020 color gamut.

[0099] In this embodiment, the optomechanical illumination system 300 further includes a first polarizing bandpass filter 333 and a second polarizing bandpass filter 334. The first polarizing bandpass filter 333 is disposed on the beam-splitting surface of the first beam splitter and combiner 331, and the second polarizing bandpass filter 334 is disposed on the beam-splitting surface of the second beam splitter and combiner 332.

[0100] The first polarizing bandpass filter 333 and the second polarizing bandpass filter 334 have different band specifications. As an example, the first polarizing bandpass filter 333 and the second polarizing bandpass filter 334 can be selected from... Figure 15 The polarizing bandpass filter shown.

[0101] Please refer to the following: Figure 13 and Figure 15 As shown, the center wavelength of the first polarizing bandpass filter 333 and the second polarizing bandpass filter 334 can be 639 nm. Red P-polarized light can pass through the first polarizing bandpass filter 333 and the second polarizing bandpass filter 334 and be incident on the second spatial light modulator 322 for modulation. Red S-polarized light, green light, and blue light are reflected to the second spatial light modulator 322 for modulation. By adjusting the ratio between red P-polarized light and red S-polarized light, the optical power balance of the dual spatial light modulators can be achieved. Of course, the optomechanical illumination system 300 can also use a dichroic filter or other beam-splitting components that can meet the requirements to split the red light.

[0102] In one embodiment, the ratio between red P-polarized light and red S-polarized light can be adjusted by a polarization converter. The polarization converter can convert the red light with the highest optical power into the required polarization state. Then, according to the gating control of the polarization converter, the duty cycle between red P-polarized light and red S-polarized light can be adjusted.

[0103] In this embodiment, the laser source 310 includes a first laser 3111, a second laser 3112, a third laser 3113, and a polarization converter 3114. The first laser 3111 emits a first color light (e.g., green light), the second laser 3112 emits a second color light (e.g., blue light), and the third laser 3113 emits a third color light (e.g., red light). The polarization converter 3114 converts the polarization state of the third color light to obtain a first polarized light (e.g., red P-polarized light) and a second polarized light (e.g., red S-polarized light), and adjusts the ratio between the first polarized light and the second polarized light.

[0104] The laser source 310 also includes three collimating lenses 3115, which are respectively disposed in the output optical paths of the first laser 3111, the second laser 3112 and the third laser 3113, and are used to collimate the first color light, the second color light and the third color light before emitting them to form a collimated beam.

[0105] Other details regarding the laser source 310 can be found in the descriptions above, and will not be repeated here. Additionally, for structural features of other parts of the optomechanical illumination system 300 provided in the second embodiment of this application, please refer to the descriptions above.

[0106] Figure 16 In another embodiment of this application, a color timing diagram of a single DMD and optomechanical illumination system is provided. In some implementations, the duty cycle of red P-polarized light and red S-polarized light can be adjusted to 0.956:0.044, thereby allocating blue light, green light, and red light (i.e., red S-polarized light) with a power ratio of 0.044 in the first spatial light modulator 321, and red light (i.e., red P-polarized light) with a power ratio of 0.956 in the second spatial light modulator 322. This can achieve optical power balance of the dual spatial light modulators in the Rec. 2020 color gamut.

[0107] Figure 17 This is a schematic diagram of the structure of an optomechanical illumination system provided in another embodiment of this application. Please refer to [link / reference]. Figure 17 As shown, in another embodiment, the ratio between red P-polarized light and red S-polarized light can be adjusted by laser modules with different polarization states.

[0108] In this embodiment, the laser source 310 includes a first laser 3121, a second laser 3122, a first polarized laser 3123, and a second polarized laser 3124. The first laser 3121 emits a first color light (e.g., green light), the second laser 3122 emits a second color light (e.g., blue light), the first polarized laser 3123 emits first polarized light (e.g., red P-polarized light), and the second polarized laser 3124 emits second polarized light (e.g., red S-polarized light). Therefore, the ratio between the first polarized light and the second polarized light can be adjusted by controlling the duty cycle of the first polarized laser 3123 and the second polarized laser 3124.

[0109] The laser source 310 also includes a polarizing mirror 3125 and a polarizing beam combiner 3126. The polarizing mirror 3125 guides first polarized light to the polarizing beam combiner 3126, or guides second polarized light to the polarizing beam combiner 3126. The polarizing beam combiner 3126 combines the first and second polarized light to form a third color light. As an example, the polarizing beam combiner 3126 is disposed in the optical path of the first polarized laser 3123, and the polarizing mirror 3125 is disposed in the optical path of the second polarized laser 3124, with the polarizing mirror 3125 guiding the second polarized light to the polarizing beam combiner 3126.

[0110] The polarized light combining device 3126 is equipped with a third polarizing bandpass filter 3129. The third polarizing bandpass filter 3129 can be the same polarizing bandpass filter as the first polarizing bandpass filter 333, allowing the third-color light formed by the combined light from the third polarizing bandpass filter 3129 to be split by the first polarizing bandpass filter 333 into first-polarized light and second-polarized light. Other details regarding the laser source 310 can be found in the relevant descriptions in the other embodiments described above, and will not be repeated here.

[0111] The optomechanical illumination system 300 provided in the second embodiment of this application can pre-set the ratio between red P-polarized light and red S-polarized light through a polarization converter 3114 or a first polarization laser 3123 and a second polarization laser 3124. A polarization bandpass filter is set in the first light splitter and combiner 331 to transmit red P-polarized light to the second spatial light modulator 321 for modulation, and reflect red S-polarized light, green light and blue light to the second spatial light modulator 322 for modulation. The optical power balance of the dual spatial light modulators can be achieved in the Rec.2020 color gamut.

[0112] It should be noted that the optomechanical illumination system improved in this application embodiment can dynamically adjust the beam splitting scheme for different color gamuts. For example, in the first embodiment, green light has the highest optical power, and beam splitting of green light can achieve optical power balance; in the second embodiment, red light has the highest optical power, and beam splitting of red light can achieve optical power balance. Similarly, in some color gamuts, blue light has the highest optical power, and beam splitting of blue light can achieve optical power balance. The specific beam splitting strategy can be found in the above embodiments and will not be repeated here.

[0113] This application also provides a projector, including a housing (not shown) and an optical-mechanical illumination system disposed within the housing.

[0114] For detailed structural features of the optomechanical illumination system, please refer to the relevant descriptions in the above embodiments. Since this projector includes the optomechanical illumination system described above, it possesses all the beneficial effects of such a system, which will not be repeated here. The structural features of other parts of the projector are within the understanding of those skilled in the art and will not be described further here.

[0115] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. An optical mechanical illumination system, characterized in that, include: A light source module is used to emit three primary color lights, which include a first color light, a second color light, and a third color light. The light power of the third color light is greater than the light power of the first color light and greater than the light power of the second color light. The third color light includes first polarized light and second polarized light. as well as A first spatial light modulator, a second spatial light modulator, a first light splitter and combiner, and a second light splitter and combiner; The first light splitter and combiner is used to guide the first polarized light to the first spatial light modulator for modulation, and to guide the second polarized light to the second spatial light modulator for modulation. The first light splitter and combiner is also used to guide the first colored light to the first spatial light modulator or the second spatial light modulator for modulation, and to guide the second colored light to the first spatial light modulator or the second spatial light modulator for modulation. The second light splitter and combiner is used to combine the first colored light, the second colored light, the first polarized light, and the second polarized light modulated by the first spatial light modulator and the second spatial light modulator, and then emit the combined light.

2. The optomechanical illumination system according to claim 1, characterized in that, The light source module is also used to adjust the ratio of the first polarized light to the second polarized light.

3. The optomechanical illumination system according to claim 2, characterized in that, The light source module includes: A first laser is used to emit the first color light; A second laser is used to emit the second color light; A third laser, used to emit the third color light; and A polarization converter is used to convert the polarization state of the third color light to obtain the first polarized light and the second polarized light, and to adjust the ratio between the first polarized light and the second polarized light.

4. The optomechanical illumination system according to claim 2, characterized in that, The light source module includes: A first laser is used to emit the first color light; A second laser is used to emit the second color light; A first polarized laser, used to emit the first polarized light; and A second polarized laser is used to emit the second polarized light.

5. The optomechanical illumination system according to claim 4, characterized in that, The light source module further includes a polarizing reflector and a polarizing beam combiner; the polarizing reflector is used to guide the first polarized light to the polarizing beam combiner, or to guide the second polarized light to the polarizing beam combiner; the polarizing beam combiner is used to combine the first polarized light and the second polarized light to form the third color light.

6. The optomechanical illumination system according to claim 1, characterized in that, The first color light is red light, the second color light is blue light, the third color light is green light, the first polarized light is green P-polarized light, and the second polarized light is green S-polarized light; The first light splitter and combiner is used to guide the red light and the green S-polarized light to the first spatial light modulator for modulation, and to guide the blue light and the green P-polarized light to the second spatial light modulator for modulation.

7. The optomechanical illumination system according to claim 6, characterized in that, The optomechanical illumination system further includes a first dichroic filter and a second dichroic filter, wherein the first dichroic filter is disposed on the beam-splitting surface of the first beam splitter and combiner, and the second dichroic filter is disposed on the beam-splitting surface of the second beam splitter and combiner.

8. The optomechanical illumination system according to claim 1, characterized in that, The first color light is green light, the second color light is blue light, the third color light is red light, the first polarized light is red P-polarized light, and the second polarized light is red S-polarized light; The first light splitter and combiner is used to guide the green light, the blue light and the red S-polarized light to the first spatial light modulator for modulation, and to guide the red P-polarized light to the second spatial light modulator for modulation.

9. The optomechanical illumination system according to claim 8, characterized in that, The optomechanical illumination system further includes a first polarizing bandpass filter and a second polarizing bandpass filter. The first polarizing bandpass filter is disposed on the beam-splitting surface of the first beam splitter and combiner, and the second polarizing bandpass filter is disposed on the beam-splitting surface of the second beam splitter and combiner.

10. The optomechanical illumination system according to claim 1, characterized in that, The optomechanical illumination system also includes a reflecting lens, a light homogenizing device, and a relay lens group; The reflecting lens is used to guide the three primary colors of light emitted by the light source module to the light homogenizing device. The light homogenizing device is used to homogenize the three primary colors of light emitted by the reflecting lens. The relay lens group is used to relay the three primary colors of light emitted by the light homogenizing device to the first light splitting and combining device.

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