CN113970873A

CN113970873A - Optical machine illumination system

Info

Publication number: CN113970873A
Application number: CN202010725509.8A
Authority: CN
Inventors: 赵鹏; 许擎栋; 胡飞; 李屹
Original assignee: Appotronics Corp Ltd
Current assignee: Shenzhen Appotronics Corp Ltd
Priority date: 2020-07-24
Filing date: 2020-07-24
Publication date: 2022-01-25
Also published as: WO2022017277A1

Abstract

The embodiment of the application provides an optical machine illumination system, which comprises a laser light source, a first spatial light modulator, a second spatial light modulator, a first light splitting and combining device and a second light splitting and combining device; the laser light source is used for emitting three primary color lights, the three primary color lights comprise a first color light, a second color light and a third color light, the light power of the third color light is greater than that of the first color light and greater than that of the second color light, and the third color light comprises a first polarized light and a second polarized light; the first light splitting and combining device is used for guiding the first polarized light to the first spatial light modulator for modulation, guiding the second polarized light to the second spatial light modulator for modulation, and guiding the first color light and the second color light to the first spatial light modulator or the second spatial light modulator for modulation; the second light splitting and combining device is used for combining the modulated light beams and emitting the combined light. The light machine illumination system that this application embodiment provided has realized the light power balance under the wide colour gamut, balances the heat load simultaneously, promotes the projected light yield.

Description

Optical machine illumination system

Technical Field

The application relates to the technical field of projection, in particular to an optical machine illumination system.

Background

Conventional spatial light modulators are generally classified into two types, including transmissive and reflective, and transmissive spatial light modulators such as LCD (Liquid Crystal Display) change the refractive characteristics of Liquid Crystal molecules on an LCD panel by an external electric field with the aid of the photoelectric effect of the Liquid Crystal molecules, thereby realizing the gray scale of a picture. Reflective spatial light modulators mainly include two major types, DMD (Digital Micromirror Device) and LCOS (Liquid Crystal on Silicon). The DMD can be described as a Semiconductor switch, which is formed by gathering 50 to 130 ten thousand micromirrors on a CMOS (Complementary Metal Oxide Semiconductor) silicon substrate, each micromirror representing a pixel, and controlling the gray scale of the pixel by the flip timing of the micromirror. The flip of the normal micromirror is divided into a crossover time and a switch time, which respectively represent the micromirror state transition time and the minimum interval time for the switching of two consecutive states. Referring to fig. 1, which shows the flip timing of the DMD mirror in the related art, in a single DMD system, the timing interval shown in fig. 1 can realize 8-bit gray scales for three RGB colors, while in a dual DMD system or a triple DMD system, more image gray scales can be realized.

The uniform illumination incident to the spatial light modulator is modulated to form a picture, and the high brightness of the picture can be realized by improving the light power incident to the spatial light modulator in unit time. However, the thermal load due to illumination limits the further increase of optical power on the spatial light modulator. In a DMD, uniform light strikes a micromirror, on one hand, specular reflection generates a part of heat, and on the other hand, in order to make the light cover a full pixel, there is necessarily a certain overlap fill (a laser projection system usually reserves a part of energy for the light irradiated on a projection chip, so that the light irradiated on the chip will exceed a part of the edge of the chip, and the ratio of the light energy exceeding the chip to the total energy of the light is called overlap fill in the field.

In the related art, the overfill is reduced by improving the quality of light spots incident on the spatial light modulator, or the heat dissipation capability of the DMD is ensured by designing a structure which is beneficial to heat dissipation, so that the heat load brought by illumination is reduced. However, these methods are complicated in structure and high in cost.

The method aims at a projection system with multiple spatial light modulators, such as a double DMD projection system, balances the heat load on each spatial light modulator, and is also a method for improving the light power incident on the spatial light modulators in unit time. Fig. 2 is a schematic structural diagram of a dual DMD projection system 100 in the related art, in the dual DMD projection system 100, on one hand, a first laser group 111 generates blue excitation light for exciting a wavelength conversion device 120 to generate yellow fluorescence, which is split by a light splitting device 130 to generate red light and green light, which are respectively distributed to a first DMD141 and a second DMD142, and on the other hand, a second laser group 112 provides blue laser to fill the first DMD141 according to a time sequence, so that the thermal power consumption balance of the dual spatial light modulator can be realized under a specific color gamut requirement. However, there is a great difference in the optical power of different color lights in different color domains, for example, in the laser fluorescent light source, the green light wavelength range is 490nm-580nm, and the luminous efficiency is 509lm/W, while in the laser light source, the green light wavelength is 525nm, and the luminous efficiency reaches 541.8 lm/W. Therefore, the luminous efficiency of three color lights is very different under different color gamut, and the light power of the three color lights required for synthesizing white light is also different. Due to the wide spectrum characteristic of fluorescence, the color gamut of the dual DMD projection system 100 is narrower, and it is difficult to adapt to the requirements of different color gamuts. Meanwhile, the dual DMD projection system 100 cannot achieve dynamic adjustment while balancing the optical power.

Disclosure of Invention

An object of the present application is to provide an optical machine illumination system to solve the above problems. The embodiment of the application realizes the aim through the following technical scheme.

The embodiment of the application provides an optical machine illumination system, which comprises a light source module, a first spatial light modulator, a second spatial light modulator, a first light splitting and combining device and a second light splitting and combining device; the light source module is used for emitting three primary color lights, the three primary color lights comprise a first color light, a second color light and a third color light, the light power of the third color light is greater than that of the first color light and greater than that of the second color light, and the third color light comprises a first polarized light and a second polarized light; the first light splitting and combining device is used for guiding the first polarized light to the first spatial light modulator for modulation and guiding the second polarized light to the second spatial light modulator for modulation, and is also used for guiding the first color light to the first spatial light modulator or the second spatial light modulator for modulation and guiding the second color light to the first spatial light modulator or the second spatial light modulator for modulation; the second light splitting and combining device is used for combining the first color light, the second color light, the first polarized light and the second polarized light modulated by the first spatial light modulator and the second spatial light modulator and emitting the combined light.

In one embodiment, the light source module is further configured to adjust a ratio of the first polarized light to the second polarized light.

In one embodiment, the light source module comprises a first laser, a second laser, a third laser and a polarized light converter, wherein the first laser is used for emitting first color light; the second laser is used for emitting second color light; the third laser is used for emitting third color light; the polarized light converter is used for converting the polarization state of the third color light to obtain first polarized light and second polarized light and adjusting the proportion between the first polarized light and the second polarized light.

In one embodiment, the light source module comprises a first laser, a second laser, a first polarized light laser and a second polarized light laser, wherein the first laser is used for emitting first color light; the second laser is used for emitting second color light; the first polarized light laser is used for emitting first polarized light; the second polarized light laser emits second polarized light.

In one embodiment, the light source module further comprises a polarized light reflector and a polarized light combining device; the polarized light reflector is used for guiding the first polarized light to the polarized light combining device or guiding the second polarized light to the polarized light combining device; the polarized light combining device is used for combining the first polarized light and the second polarized light to form third colored light.

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 splitting and combining device is used for guiding the red light and the green S polarized light to the first spatial light modulator for modulation, and guiding the blue light and the green P polarized light to the second spatial light modulator for modulation.

In one embodiment, the optical-mechanical illumination system further includes a first dichroic filter and a second dichroic filter, the first dichroic filter is disposed on the splitting surface of the first dichroic combiner, and the second dichroic filter is disposed on the splitting surface of the second dichroic combiner.

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 polarized light is red S-polarized light; the first light splitting and combining device is used for guiding the green light, the blue light and the red S polarized light to the first spatial light modulator for modulation, and guiding the red P polarized light to the second spatial light modulator for modulation.

In an embodiment, the optical-mechanical illumination system further includes a first polarization band pass filter and a second polarization band pass filter, the first polarization band pass filter is disposed on the splitting surface of the first beam splitting and combining device, and the second polarization band pass filter is disposed on the splitting surface of the second beam splitting and combining device.

In one embodiment, the light engine illumination system further comprises a reflection lens, a dodging device and a relay lens group; the reflecting lens is used for guiding the tricolor light emitted by the light source module to the dodging device, the dodging device is used for dodging the tricolor light emitted by the reflecting lens, and the relay lens group is used for relaying the tricolor light emitted by the dodging device to the first light splitting and combining device.

Compared with the prior art, the ray apparatus lighting system that this application embodiment provided adopts the three primary colors light that light source module sent as projection light, and divide into first polarized light and second polarized light through the third colored light with the optical power is the highest, make first beam splitting and light combining device can be with first colored light, the second colored light, first polarized light and the balanced distribution of second polarized light are modulated to two spatial light modulators, realize the light power balance of two spatial light modulators under the wide colour gamut, when balancing two spatial light modulator heat load, make two spatial light modulators can be full-load work under the ideal condition, promote the light yield of projection, realize the high brightness of picture.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

Fig. 1 is a timing diagram illustrating the inversion of a DMD mirror in the related art.

Fig. 2 is a schematic diagram of a dual DMD projection system in the related art.

Fig. 3 is a comparison diagram of different bit depth pictures in the related art.

FIG. 4 is a timing diagram of color light with a single DMD and a dual DMD in the related art.

Fig. 5 is a CIE 1931 color gamut diagram in the related art.

Fig. 6 is a graph of visual effect functions of color lights of different wavelengths in the related art.

Fig. 7 is a schematic structural diagram of an optical bench illumination system according to an embodiment of the present application.

Fig. 8 is a graph of the ratio of blue-green laser power and red laser power to red laser wavelength in the related art.

FIG. 9 is a P-polarized light-gated spectrum of a dichroic filter provided by the embodiment shown in FIG. 7.

FIG. 10 is the S-polarized light-gating spectrum of the dichroic filter provided by the embodiment shown in FIG. 7.

Fig. 11 is a timing diagram of color light for a single DMD and opto-mechanical illumination system provided by the embodiment shown in fig. 7.

Fig. 12 is a schematic structural diagram of an optical engine illumination system provided in another embodiment of the embodiment shown in fig. 7.

Fig. 13 is a schematic structural diagram of an optical bench lighting system according to another embodiment of the present application.

Fig. 14 is a three primary color coordinate specified by the rec.2020 color gamut in the related art.

FIG. 15 is a spectrum of a polarizing bandpass filter provided by the embodiment shown in FIG. 13.

Fig. 16 is a timing diagram of color light for the single DMD and opto-mechanical illumination system provided by the embodiment shown in fig. 13.

Fig. 17 is a schematic structural diagram of an optical engine illumination system provided in another embodiment of the embodiment shown in fig. 13.

Detailed Description

To facilitate an understanding of the embodiments of the present application, the embodiments of the present application will be described more fully below with reference to the accompanying drawings. Preferred embodiments of the present application are given in the accompanying drawings. This application may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

Unless defined otherwise, 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 herein in the examples of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

Aiming at the problems that a double-spatial-light-modulator projection system in the related art cannot meet the requirements of different color gamuts and the like easily, the applicant creatively provides an optical machine illumination system, wherein three primary colors of light emitted by a light source module are used as projection light, when the light power of the three primary colors of light is different, the color light with the highest light power can be split by a light splitting and combining device and is distributed to two spatial light modulators to be modulated in a balanced manner with the other two color lights, the light power balance of the double-spatial-light-modulator can be realized under the wide color gamut, the spatial light modulators can work fully under the ideal condition while the heat load of the double-spatial-light-modulator is balanced, the light output of projection is improved, and the high brightness of pictures is realized.

The projection system with the double spatial light modulators provided by the embodiment of the application can be applied to cinema projectors, education projectors, laser televisions, micro projectors, engineering projectors and the like, and the application does not specifically limit the application.

First, a brief description will be made of terms involved in the embodiments of the present invention:

the display bit depth (bit depth) is the number of bits required for representing the gray information of a certain pixel in a gray image, and when the bit depth is larger, the difference between adjacent gray values is smaller, and the picture displayed by the digital image is closer to the display under the normal condition. Fig. 3 is a comparison graph of pictures with different bit depths in the related art, and it can be seen that the larger the bit depth is, the more the fineness and richness of the image picture can be greatly improved. Therefore, the improvement of the bit depth is a very important index in the display industry and is also a pursuit of high-end display in the future.

The display bit depth represents the number of gray levels, e.g. 8 bit depth picture, representing gray levels having 2⁸256 gray levels. For example, for a DMD, a color timing chart of a single DMD and a double DMD shown in fig. 4 is required to realize white light in a certain color gamut, please refer to fig. 4, where an idle interval in the color timing chart is spoke (spoke) in a timing chart set for reducing color break up (also referred to as "rainbow effect" or "color separation") in some laser fluorescent projection systems. The spoke phenomenon is that when a fluorescent color wheel or a color filter wheel with various color schemes is adopted, and light irradiates at a junction of two colors, the situation of impure colors can occur (for example, the junction of red and blue colors is irradiated simultaneously, red light and blue light can be emitted simultaneously, and red light of an emergent product is emitted) The current solution is to not emit a picture during the time period at that location, so that a completely black picture appears when the entire image is sampled. It can be known from fig. 4 that, at the same frame rate, the dual spatial light modulator system can provide more color time ratios after performing reasonable light splitting, so that the dual spatial light modulator provided by the present application can increase the display bit depth of an image, improve the contrast in a frame, have a higher brightness picture, and provide a better display effect compared with a single spatial light modulator. In addition, compared with other projection systems with multiple spatial light modulators, such as the projection system of a three-spatial light modulator system, the double-spatial light modulator projection system has the advantages of simpler overall structure, fewer used devices and lower cost.

Fig. 5 is a CIE 1931 color gamut diagram in the related art, and please refer to fig. 5, in which the color gamut of the human eye can refer to the CIE 1931 color gamut diagram. Under normal conditions, projection or display pictures adopt RGB tricolor light, and corresponding colors can be output by configuring the proportion of the RGB tricolor light. When the color coordinates selected for the RGB tricolor light are different, the display or projection will contain a different range of color gamut. The edge of the CIE 1931 color gamut diagram is composed of monochromatic light with continuously changing wavelengths of 380nm-780nm, and the closer to the center, the wider the spectral line of the spectrum. The coverage of the current common Rec.709 color gamut is less than half of the whole color gamut, while the coverage of the Rec.2020 color gamut adopting monochromatic light as RGB primary colors is close to nine times of the whole color gamut.

Fig. 6 is a graph of visual effect functions of color lights with different wavelengths in the related art, please refer to fig. 6, where color lights with different wavelength ranges have different visual effects, when the visual effects of monochromatic lights are considered, the luminous flux of the monochromatic light is obtained by multiplying the effective value at the wavelength by the light power, and if the color light has a certain spectral line, the product of the luminous power spectral line and the visual effect of the color light needs to be integrated, as shown in the following equation (1):

L＝∫P_λ·V_λdλ (1)

according to the color coordinates of the tricolor light required by a specific color gamut, the corresponding D65 white light can be calculated according to the formula (2) and the formula (3)The lumen ratio of RGB tricolor light is L_R:L_G:L_B＝Y_R:Y_G:Y_B。

In the formula (2) and the formula (3), x and Y are known color coordinates, and Y is a color coordinate_iFor the lumen ratio to be solved, the lumen ratio of the RGB tricolor light can be solved according to the formula (2) and the formula (3).

The required light power is calculated according to the specific color gamut, and in general, since the visual efficiency of green light is high, the corresponding light power is large, and the green light needs to be split. In some color gamut situations, the red light has a high percentage and the optical power is the largest, and the optimal way is to split the red light. In this case, if the solution of the projection system 100 with dual spatial light modulators (see fig. 2 for details) is adopted, it will inevitably cause the light power to be distributed unevenly on the dual spatial light modulators. The optical machine illumination system provided by the embodiment of the application can dynamically adjust the light splitting strategy according to different color gamuts, for example, light splitting is performed on green light in certain color gamuts, or light splitting is performed on red light in certain color gamuts, so that the light power balance of the double spatial light modulators in different color gamuts can be realized.

Currently, there are relatively few approaches to adopt a light splitting strategy for dual spatial light modulators to balance the optical power. In a related technology, a multi-primary color double-DMD laser projection display device is provided, which emits laser light through laser light source modules I and II, wherein the laser light source module I comprises a red light laser light source and is recorded as R_ARed laser light source is denoted as R_BGreen laser light source G_B(ii) a The laser light source module II comprises a blue light laser light source and is marked as B_AAnd the blue laser light source is marked as B_BGreen laser light sourceIs marked as G_A. The multi-primary-color double-DMD laser projection display device adopts a multi-primary-color laser light source and a double-DMD structure, so that the coverage rate of a color gamut is improved, but the technical problem that the optical power output by a double-spatial light modulator is unbalanced is not found.

In another related technology, an imaging system based on dual DMDs is provided, where the imaging system analyzes a received current image through a microprocessor to determine whether a saturated region exists in the current image, the microprocessor performs time domain dimming on a first DMD when determining that the saturated region exists in the received current image, the microprocessor analyzes the current image obtained after the time domain dimming, determines whether the saturated region still exists in the current image, and the microprocessor performs space domain dimming on a second DMD when determining that the saturated region still exists in the current image received after the time domain dimming. Therefore, time domain dimming and space domain dimming are combined by utilizing the two DMDs, the image quality is ensured, and the dynamic range of the image is expanded. However, the core point of the imaging system is to realize a high dynamic range image of the dual spatial light modulator, and the technical problem of unbalanced optical power of the dual spatial light modulator is not found, and the application scene is not in the category of three primary color laser projection.

Fig. 7 is a schematic structural diagram of an optical-mechanical illumination system according to an embodiment of the present disclosure, please refer to fig. 7, in which the optical-mechanical illumination system 200 includes a light source module 210, a first spatial light modulator 221, a second spatial light modulator 222, a first light splitting and combining device 231, and a second light splitting and combining device 232.

The light source module 210 may be a laser light source, and the light source module 210 is configured to emit three primary colors of light, where the three primary colors of light include a first color of light, a second color of light, and a third color of light, and a light power of the third color of light is greater than a light power of the first color of light and greater than a light power of the second color of light. The third color light includes the first polarized light and the second polarized light. In some embodiments, the Light source module 210 may also be a Light Emitting Diode (LED) Light source, and the LED Light source may also emit tricolor Light.

Where tricolor light refers to the base light that can be used to synthesize other colors of light, it can be monochromatic light such as red, green, and blue light commonly used in the art. The third color light is polarized light, the polarized light can be represented by a vector sum of S polarized light and P polarized light, the first polarized light can be one of the P polarized light and the S polarized light, and the second polarized light can be the other of the P polarized light and the S polarized light.

The first spatial light modulator 221 and the second spatial light modulator 222 may be a DMD, LCOS, LCD, or other device that implements spatial light modulation.

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

The second light splitting and combining device 232 is configured 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 emit the combined light.

In implementation, the ratio between the first polarized light and the second polarized light may be preset according to the ratio of the optical powers of the first color light, the second color light and the third color light, and 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 may be selectively guided to the first spatial light modulator 221 or the second spatial light modulator 222 for modulation, so that the optical powers of the first spatial light modulator 221 and the second spatial light modulator 222 are balanced.

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 the optical power of the second color light, the ratio between the first polarized light and the second polarized light may be preset so that the sum of the optical powers of the first polarized light and the first color light is equal to or nearly equal to the sum of the optical powers of the second polarized light and the second color light, at this time, the first polarized light and the first color light are selectively 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 that the optical power balance between the first spatial light modulator 221 and the second spatial light modulator 222 can be realized.

When the light power of the third color light is much greater than the light powers of the first color light and the second color light, the ratio between the first polarized light and the second polarized light may be set so that the sum of the light powers of the first polarized light, the first color light, and the second color light is equal to or nearly equal to the light 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 that the light power balance between the first spatial light modulator 221 and the second spatial light modulator 222 can be realized.

In this embodiment, the light source module 210 is further configured to adjust a 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 ratio between the first polarized light and the second polarized light, so that the optical-mechanical illumination system 200 can be flexibly applied to a plurality of different color gamuts, and the light power balance between the first spatial light modulator 221 and the second spatial light modulator 222 is realized under different color gamuts.

The optical machine illumination system 200 uses tricolor light as projection light, and since the color coordinate points of the monochromatic light are distributed on the boundary of the color gamut, a wide color gamut can be realized. It should be noted that a wide color gamut, such as the rec.2020 color gamut (see fig. 5 in detail), is a very strict color gamut standard, and the luminous efficacy of the corresponding tricolor light is not high. Especially, in the red light band, the electro-optical efficiency of the red laser is not high, and the temperature control is required, so some trade-offs (trade off) are required for the actual engineering requirements.

Referring to fig. 6 and 7 together, the luminous efficacy of 630nm red light meeting the rec.2020 color gamut standard is not high, but slightly shifted, for example, 620nm red light is increased by more than 40% compared to 630nm red light. Taking into account cost considerations, the use of a higher photopic efficiency red laser or red fluorescence (e.g., 620nm wavelength) without deviating too far from the high gamut apex is a sensible and effective choice. In this case, however, the light power of the tricolor light is often no longer predominant for red light (the light power for red light is higher than the sum of the light powers for blue and green light).

Fig. 8 is a graph showing the relationship between the ratio of the blue-green laser power to the red laser power and the red laser wavelength in the related art, and please refer to fig. 7 and 8, in the red light with the wavelength range of 610nm to 630nm, when the wavelength of the red light is less than 627nm, the sum of the blue-green light optical power is greater than the red light optical power. Even if the red light with the wavelength of 610nm is selected, the decrease of the color gamut coverage is very limited as can be seen from the CIE 1931 color gamut diagram, so that the low-wavelength red light with higher light visual effect can be selected, and the selection also leads the sum of the light power of the blue green light to be larger than that of the red laser light.

As an example, the optical-mechanical illumination system 200 may split green light to achieve light power balance of the dual spatial light modulator, so that the technical solution of the present application is more universal. For example, when the wavelengths of RGB tricolor light composing D65 white light are respectively selected from 620nm, 550nm and 455nm, the ratio of light power of RGB tricolor light is P_R:P_G:P_B1: 1.206: 0.422. In this case, the light power of the green light is greater than the light power of the red light and greater than the light power of the blue light, and the green light can be reasonably split by the first light splitting and combining device 231, so as to meet the requirement of balancing the light power.

In this 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, the second polarized light is green S-polarized light, that is, the green light has the highest optical power, and the green light is polarized light, and includes proportion-adjustable green P-polarized light and green S-polarized light. The first light splitting and combining device 231 is used for guiding the red light and the green S-polarized light to the first spatial light modulator 221 for modulation, and for guiding the blue light and the green P-polarized light to the second spatial light modulator 222 for modulation, so that the light power balance of the dual spatial light modulators can be realized in a color gamut in which the green light is the color light with the highest light power.

In this embodiment, a dichroic filter may be employed to split the green light. The optical-mechanical illumination system 200 further includes a first dichroic filter 233 and a second dichroic filter 234, the first dichroic filter 233 is disposed on the light splitting surface of the first light splitting and combining device 231, and the second dichroic filter 234 is disposed on the light splitting surface of the second light splitting and combining device 232. The first dichroic filter 233 has a difference in wavelength gating between the green P-polarized light and the green S-polarized light, and according to this feature, the green wavelength matched to the first dichroic filter 233 can be selected, so that the first dichroic filter 233 can reflect the red light and the green S-polarized light to the first spatial light modulator 221 for modulation, and transmit the blue light and the green P-polarized light to the second spatial light modulator 222 for modulation.

Fig. 9 and 10 are gate spectra of P-polarized light and S-polarized light of the dichroic filter provided in the embodiment of the present application, the first dichroic filter 233 and the second dichroic filter 234 may employ dichroic filters having the gate spectra shown in fig. 9 and 10, the cut-off wavelength of the first dichroic filter 233 and the second dichroic filter 234 may be 550nm, and a gap of about 5nm exists in their gate threshold, and this gap is suitable for adding green light having a wavelength of 550 nm.

When green P-polarized light of 550nm is used, the first dichroic filter 233 and the second dichroic filter 234 transmit the green P-polarized light. When green S-polarized light of 550nm is used, the first dichroic filter 233 and the second dichroic filter 234 reflect the green S-polarized light. Meanwhile, the first dichroic filter 233 and the second dichroic filter 234 highly transmit light lower than the cutoff wavelength and highly reflect light higher than the cutoff wavelength. The first dichroic filter 233 may 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 distributed to the first spatial light modulator 221 and the second spatial light modulator 222 in an equalized manner for modulation.

In one embodiment, the ratio between the first polarized light and the second polarized light may be adjusted by a polarized light converter. In this embodiment, the light source module 210 may 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 polarized light converter 2114.

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

The polarization converter 2114, also called pcs (polarization conversion system), may be composed of a PBS (Polarized Beam Splitter) array and a half-wave plate. Taking the third color light as green light 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 disposed on the exit surface of the green S polarized light, the green S polarized light can be converted into the green P polarized light, and the ratio between the green S polarized light and the green P polarized light can be adjusted.

It should be noted that, the wavelengths of the first dichroic filter 233, the second dichroic filter 234 and the green light are adapted, and when the third color light is red light or blue light or green light with some other wavelengths, a person skilled in the art may select some other dichroic filters, polarization band pass filters, or other light splitting components that can achieve the requirements, as long as balanced distribution of the three primary color lights can be achieved, and the light power balance of the dual spatial light modulator is achieved.

Fig. 11 is a color light timing diagram of a single DMD and opto-mechanical illumination system provided in this embodiment, in some embodiments, the duty ratio between the green P-polarized light and the green S-polarized light may be controlled to be 0.74:0.26, so that the first spatial light modulator 221 distributes the green light with the red light power ratio of 0.26 (i.e., green S-polarized light), and the second spatial light modulator 222 distributes the green light with the blue light power ratio of 0.74 (i.e., green P-polarized light), and the light power balance of the dual spatial light modulators may be achieved in this color gamut (the power of the green light is greater than the light power of the red light, and the power of the green light is greater than the light power of the blue light).

Still referring to fig. 7, in this embodiment, the light source module 210 may further include three collimating lenses 2115, where the three collimating lenses 2115 are respectively disposed on the emitting light 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, and compared with before collimation, the divergence angle of the collimated light beam is greatly compressed, so as to reduce loss of the light beam during the propagation process.

The optical engine illumination system 200 further includes a reflective lens 251, a dodging device 252 and a relay lens group 253. The reflection lens 251 is used for guiding the tricolor light emitted by the light source module 210 to the dodging device 252, the dodging device 252 is used for dodging the tricolor light emitted by the reflection lens 251, and the relay lens group 253 is used for relaying the tricolor light emitted by the dodging device 252 to the first light splitting and combining device 231.

The reflective lens 251 is used for changing the optical path of the tricolor light, so that the tricolor light can be incident to the light uniformizing device 252 for light uniformization. The reflective lens 251 may include a first reflective sub-lens 2511 and a second reflective sub-lens 2512, the first reflective sub-lens 2511 being configured to reflect blue light to the light unifying device 252 and transmit red light to the light unifying device 252. The second reflection sub-lens 2512 is used for reflecting the green light to the dodging device 252 and transmitting the red light and the blue light to the dodging device 252, so that the tricolor light can be ensured to be incident to the dodging device 252. It should be noted that the number and kinds of optical elements included in the reflection lens 251 for changing the optical path are not limited in the embodiments of the present application, and all optical path conversion components for receiving the tricolor light and transmitting the tricolor light to the dodging device 252 belong to the protection scope of the present application.

The light homogenizing device 252 can homogenize the tricolor light, thereby avoiding burning caused by excessive local impact and uneven brightness of the output image. The light homogenizing device 252 may be any one of a light rod, a fly-eye lens, and a light cone.

The relay lens group 253 is used for collecting and converging the tricolor light emitted by the dodging device 252 and providing the tricolor light to the first light splitting and combining device 231, and the relay lens group 253 can be formed by combining a plurality of collecting lenses, such as convex lenses and concave lenses.

The opto-mechanical illumination system 200 also includes a first total internal reflection prism 261 and a second total internal reflection prism 262. The first tir prism 261 is configured to reflect the light beam emitted by the first beam splitting and combining device 231 to the first spatial light modulator 221 for modulation, and then emit the light beam to the second beam splitting and combining device 232. The second tir prism 262 is used for reflecting the light beam emitted from the first beam splitting and combining device 231 to the second spatial light modulator 222 for modulation, and then emitting the light beam to the second beam splitting and combining device 232.

The first total internal reflection prism 261 and the second total internal reflection prism 262 may be formed by splicing two triangular prism prisms, and light is incident to the first total internal reflection prism 261 and the second total internal reflection prism 262 to be totally reflected, so that more light enters the first spatial light modulator 221 and the second spatial light modulator 222, and the light collection capability of the optical engine illumination system 200 may be improved.

The optical-mechanical illumination system 200 further includes a lens 263, where the lens 263 is configured to receive the combined light emitted from the second light splitting and combining device 232 to finally form an image.

Fig. 12 is a schematic structural diagram of an optical-mechanical illumination system according to another embodiment of the present application, please refer to fig. 12, in another embodiment, a ratio between a first polarized light and a second polarized light can be adjusted by laser modules with different polarization states.

In this embodiment, the light source module 210 may 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.

First laser 2121 is configured to emit a first color light (e.g., red light), second laser 2122 is configured to emit a second color light (e.g., blue light), first polarized laser 2123 is configured to emit a first polarized light (e.g., green P-polarized light), and second polarized laser 2124 is configured to emit a second polarized light (e.g., green S-polarized light), and a ratio between the first polarized light and the second polarized light can be adjusted by controlling a duty ratio of on/off of first polarized laser 2123 and second polarized laser 2124.

In this embodiment, the light source module 210 further includes a polarized light reflector 2125 and a polarized light combining device 2126. The polarizing light reflector 2125 is used for guiding the first polarized light to the polarizing light combining device 2126 or guiding the second polarized light to the polarizing light combining device 2126. The polarization light combining device 2126 is configured to combine the first polarization light and the second polarization light to form a third color light. As an example, the polarization beam combiner 2126 is disposed on the optical path of the first polarization laser 2123, the polarization beam reflector 2125 is disposed on the optical path of the second polarization laser 2124, and the polarization beam reflector 2125 is configured to guide the second polarization beam to the polarization beam combiner 2126.

The polarized light reflector 2125 is configured to change an 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 to the polarized light combining device 2126 for combining. The polarizing light reflector 2125 may be a plane reflector or a curved reflector, and may be specifically configured according to actual needs.

The combined polarization light device 2126 is provided with a third dichroic filter 2128, and the third dichroic filter 2128 may be a dichroic filter consistent with the first dichroic filter 233, so that the third dichroic filter 2128 combines the first polarized light and the second polarized light to form a third color light, which is split by the first dichroic filter 233 to form the first polarized light and the second polarized light.

The first polarized light emitted by the first polarized light laser 2123 and the second polarized light emitted by the second polarized light laser 2124 may be directly incident to the light uniformizing device 252 for light combination, or may be combined by the polarized light combining device 2126 and then incident to the light uniformizing device 252, and the specific form is not limited.

In this embodiment, the light source module 210 further includes four collimating lenses 2127, and the four collimating lenses 2127 are respectively disposed on the light emitting paths of the first laser 2121, the second laser 2122, the first polarized laser 2123, and the second polarized laser 2124, and are configured to collimate the first color light, the second color light, the first polarized light, and the second polarized light and then emit the first color light, the second color light, the first polarized light, and the second polarized light to form a collimated light beam.

The light machine illumination system 200 provided in the embodiment of the present application can set the ratio between the green P-polarized light and the green S-polarized light by the polarized light converter 2114 or the first polarized light laser 2123 and the second polarized light laser 2124 in different polarization states, and set the dichroic filter in the first light splitting and combining device 231 to reflect the red light and the green S-polarized light to the first spatial light modulator 221 for modulation, transmit the blue light and the green P-polarized light to the second spatial light modulator 222 for modulation, and can realize the light power balance of the dual spatial light modulators in the color gamut where the light power of the green light is greater than the light power of the red light and the blue light.

Fig. 13 is a schematic structural diagram of an optical-mechanical illumination system according to another embodiment of the present application, please refer to fig. 13, and the optical-mechanical illumination system 300 according to this embodiment can also achieve optical power balance of the dual spatial light modulator in a color gamut (e.g., a rec.2020 color gamut) in which the optical power of red light is greater than the optical power of green light and blue light.

In this 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 polarized light is red S-polarized light. That is, the light power of the red light is the highest, and the red light is polarized light, and includes red P-polarized light and red S-polarized light with adjustable proportion.

At some high end display scenarios, the rec.2020 gamut is just needed. The color coordinates of the three primary colors of RGB used by the rec.2020 color gamut are shown in fig. 14 according to the specification of the ITU-R Recommendation bt.2020 standard.

As can be known from the CIE 1931 color gamut diagram, the three primary colors of the rec.2020 color gamut are monochromatic lights, and in order to implement the rec.2020 color gamut standard, a laser light source is considered to be used as the light source of the three primary colors, so that the optical-mechanical lighting system 200 can implement the light power balance of the dual spatial light modulator in the rec.2020 color gamut.

The light power output of the RGB tricolor light corresponding to the rec.2020 color gamut can be calculated as P according to the formula (2) and the formula (3) and fig. 6_R:P_G:P_BThe optical power output corresponds to a white light of D65, 1: 0.8399: 0.0713. It can be found that in the rec.2020 color gamut, the optical power of red light dominates, i.e. the optical power of red light is larger than the optical power of green light and larger than the optical power of blue light. In this case, the division of green light in the first embodiment does not achieve the optical power balance of the dual spatial light modulator. Red light may be split for the rec.2020 color gamut.

The optical-mechanical illumination system 300 converts red light into a polarization state, sets a ratio between red P-polarized light and red S-polarized light, and then the first light splitting and combining device 331 can reflect green light, blue light, and red S-polarized light to the first spatial light modulator 321 for modulation, and transmit red P-polarized light to the second spatial light modulator 322 for modulation, so that light power balance of the dual spatial light modulators can be realized in the color gamut of rec.2020.

In this embodiment, the optical illumination system 300 further includes a first polarization bandpass filter 333 and a second polarization bandpass filter 334, the first polarization bandpass filter 333 is disposed on the splitting surface of the first beam splitting and combining device 331, and the second polarization bandpass filter 334 is disposed on the splitting surface of the second beam splitting and combining device 332.

The first and second polarization bandpass filters 333 and 334 have different wavelength band specifications, and as an example, the first and second polarization bandpass filters 333 and 334 may be selected from the polarization bandpass filters shown in fig. 15.

As shown in fig. 13 and fig. 15, the central wavelength of the first polarization bandpass filter 333 and the second polarization bandpass filter 334 may be 639nm, the red P-polarized light may be transmitted through the first polarization bandpass filter 333 and the second polarization bandpass filter 334 to enter the second spatial light modulator 322 for modulation, the red S-polarized light, the green light, and the blue light are reflected to the second spatial light modulator 322 for modulation, and the optical power balance of the dual spatial light modulators may be achieved by adjusting the ratio between the red P-polarized light and the red S-polarized light. Of course, the opto-mechanical illumination system 300 may also employ dichroic filters or other light-splitting components to split the red light as desired.

In one embodiment, the ratio between the red P-polarized light and the red S-polarized light may be adjusted by a polarized light converter, the red light with the highest optical power may be converted into the required polarized light by the polarized light converter, and then the duty ratio between the red P-polarized light and the red S-polarized light may be adjusted according to the gate control of the polarized light converter.

In the present embodiment, the laser light source 310 includes a first laser 3111, a second laser 3112, a third laser 3113, and a polarized light converter 3114. The first laser 3111 is configured to emit a first color light (e.g., green light), the second laser 3112 is configured to emit a second color light (e.g., blue light), the third laser 3113 is configured to emit a third color light (e.g., red light), and the polarization converter 3114 is configured to convert the third color light into a polarization state to obtain a first polarized light (e.g., red P-polarized light) and a second polarized light (e.g., red S-polarized light), and is configured to adjust a ratio between the first polarized light and the second polarized light.

The laser light source 310 further includes three collimating lenses 3115, where the three collimating lenses 3115 are respectively disposed on the emitting light paths of the first laser 3111, the second laser 3112 and the third laser 3113, and are configured to collimate the first color light, the second color light and the third color light and then emit the collimated light beams.

For other contents of the laser light source 310, reference may be made to the related descriptions in the above embodiments, and further description is omitted here. In addition, please refer to the related description of the above embodiments regarding the structural features of other parts of the optical engine illumination system 300 provided in the second embodiment of the present application.

Fig. 16 is a color light timing diagram of a single DMD and opto-mechanical lighting system according to another embodiment of the present application, in some embodiments, the duty ratio of red P-polarized light and red S-polarized light can be adjusted to 0.956:0.044, so that blue light, green light, and red light with a light power ratio of 0.044 (i.e., red S-polarized light) are distributed to the first spatial light modulator 321, and red light with a light power ratio of 0.956 (i.e., red P-polarized light) is distributed to the second spatial light modulator 322, so that the light power balance of the dual spatial light modulators can be realized in the rec.2020 color gamut.

Fig. 17 is a schematic structural diagram of an optical-mechanical illumination system according to another embodiment of the present application, please refer to fig. 17, in which a ratio between red P-polarized light and red S-polarized light can be adjusted by laser modules with different polarization states.

In this embodiment, laser light source 310 includes a first laser 3121, a second laser 3122, a first polarized light laser 3123, and a second polarized light laser 3124. First laser 3121 is configured to emit light of a first color (e.g., green), second laser 3122 is configured to emit light of a second color (e.g., blue), first polarized laser 3123 is configured to emit light of a first polarization (e.g., red P-polarized light), and second polarized laser 3124 is configured to emit light of a second polarization (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 on-off duty ratio of the first polarized light laser 3123 and the second polarized light laser 3124.

The laser light source 310 further includes a polarized light reflector 3125 and a polarized light combining device 3126. The polarizing light reflector 3125 is configured to direct the first polarized light to the polarization beam combining device 3126, or to direct the second polarized light to the polarization beam combining device 3126. The polarization beam combining device 3126 is configured to combine the first polarization beam and the second polarization beam to form a third color beam. As an example, the polarization beam combining device 3126 is disposed on an optical path of the first polarization laser 3123, the polarization light reflector 3125 is disposed on an optical path of the second polarization laser 3124, and the polarization light reflector 3125 is configured to guide the second polarization light to the polarization beam combining device 3126.

The polarized light combining device 3126 is provided with a third polarization bandpass filter 3129, the third polarization bandpass filter 3129 may be a polarization bandpass filter consistent with the first polarization bandpass filter 333, so that the third color light formed by combining the light of the third polarization bandpass filter 3129 may be split by the first polarization bandpass filter 333 to form the first polarized light and the second polarized light. For other contents of the laser light source 310, reference may be made to the related descriptions in the above other embodiments, and further description is omitted here.

The optical-mechanical illumination system 300 provided in the second embodiment of the present application may preset a ratio between the red P-polarized light and the red S-polarized light by the polarized light converter 3114 or the first polarized light laser 3123 and the second polarized light laser 3124, and the polarization band pass filter is disposed on the first light splitting and combining device 331, so that the red P-polarized light may be transmitted to the second spatial light modulator 321 for modulation, and the red S-polarized light, the green light, and the blue light may be reflected to the second spatial light modulator 322 for modulation, and the optical power balance of the dual spatial light modulators may be realized in the color gamut of rec.2020.

It should be noted that the improved optical machine illumination system in the embodiment of the present application may dynamically adjust the light splitting scheme for different color gamuts, for example, in the first embodiment, the light power of green light is the highest, and light splitting may be performed on green light to achieve light power balance; in the second embodiment, the optical power of the red light is the highest, and the red light can be split to realize the optical power balance. Similarly, in some color gamut, the optical power of the blue light is the highest, and the blue light may be split to achieve optical power balance, and the specific splitting strategy may refer to the content of the above embodiment, and is not described herein again.

The embodiment of the application also provides a projector, which comprises a shell (not shown) and an optical machine illumination system, wherein the optical machine illumination system is arranged in the shell.

Please refer to the related description of the above embodiments for the detailed structural features of the optical-mechanical illumination system. Since the projector includes the optical-mechanical illumination system in the above embodiment, all the advantages of the optical-mechanical illumination system are provided, and are not described herein again. The structural features of the other parts of the projector are within the understanding of those skilled in the art and will not be described in detail herein.

The above-mentioned embodiments only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present application. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

1. An opto-mechanical lighting system, comprising:

the light source module is used for emitting three primary color lights, wherein the three primary color lights comprise a first color light, a second color light and a third color light, the light power of the third color light is greater than that of the first color light and greater than that of the second color light, and the third color light comprises a first polarized light and a second polarized light; and

the system comprises a first spatial light modulator, a second spatial light modulator, a first light splitting and combining device and a second light splitting and combining device;

the first light splitting and combining device is used for guiding the first polarized light to the first spatial light modulator for modulation and guiding the second polarized light to the second spatial light modulator for modulation, and the first light splitting and combining device is also used for guiding the first color light to the first spatial light modulator or the second spatial light modulator for modulation and guiding the second color light to the first spatial light modulator or the second spatial light modulator for modulation; the second light splitting and combining device is used for combining the first color light, the second color light, the first polarized light and the second polarized light modulated by the first spatial light modulator and the second spatial light modulator and emitting the combined light.

2. The opto-mechanical illumination system of claim 1, wherein the light source module is further configured to adjust a ratio of the first polarized light to the second polarized light.

3. The opto-mechanical illumination system of claim 2, wherein the light source module comprises:

the first laser is used for emitting the first color light;

the second laser is used for emitting the second color light;

a third laser for emitting the third color light; and

and the polarized light converter is used for converting the polarization state of the third color light to obtain the first polarized light and the second polarized light and adjusting the proportion between the first polarized light and the second polarized light.

4. The opto-mechanical illumination system of claim 2, wherein the light source module comprises:

the first laser is used for emitting the first color light;

the second laser is used for emitting the second color light;

the first polarized light laser is used for emitting the first polarized light; and

and the second polarized light laser is used for emitting the second polarized light.

5. The opto-mechanical illumination system of claim 4, wherein the light source module further comprises a polarizing mirror and a polarizing combiner; the polarized light reflector is used for guiding the first polarized light to the polarized light combining device or guiding the second polarized light to the polarized light combining device; the polarized light combining device is used for combining the first polarized light and the second polarized light to form the third colored light.

6. The opto-mechanical illumination system of claim 1, wherein 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 splitting and combining device is used for guiding the red light and the green S polarized light to the first spatial light modulator for modulation, and guiding the blue light and the green P polarized light to the second spatial light modulator for modulation.

7. The opto-mechanical illumination system of claim 6, further comprising a first dichroic filter disposed at the splitting plane of the first dichroic combiner and a second dichroic filter disposed at the splitting plane of the second dichroic combiner.

8. The opto-mechanical illumination system of claim 1, wherein 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 splitting and combining device is used for guiding the green light, the blue light and the red S polarized light to the first spatial light modulator for modulation, and guiding the red P polarized light to the second spatial light modulator for modulation.

9. The optical-mechanical illumination system of claim 8, further comprising a first polarization band pass filter and a second polarization band pass filter, wherein the first polarization band pass filter is disposed on the splitting surface of the first beam splitting and combining device, and the second polarization band pass filter is disposed on the splitting surface of the second beam splitting and combining device.

10. The opto-mechanical illumination system of claim 1, further comprising a reflective lens, a light homogenizer, and a relay lens group;

the reflection lens is used for guiding the tricolor light emitted by the light source module to the dodging device, the dodging device is used for dodging the tricolor light emitted by the reflection lens, and the relay lens group is used for relaying the tricolor light emitted by the dodging device to the first light splitting and combining device.