CN111147831A

CN111147831A - Projection system and projection control method

Info

Publication number: CN111147831A
Application number: CN201811298825.0A
Authority: CN
Inventors: 胡飞; 陈晨; 郭祖强; 李屹
Original assignee: Appotronics Corp Ltd
Current assignee: Shenzhen Appotronics Corp Ltd
Priority date: 2018-11-02
Filing date: 2018-11-02
Publication date: 2020-05-12
Also published as: WO2020088163A1

Abstract

The invention relates to a projection system and a projection control method, and relates to the technical field of projection display. Wherein, projection system includes: the illumination light modulator is used for modulating the received incident light beams according to the brightness distribution information of the image to be projected so as to obtain illumination light beams, and the brightness of at least one area of each illumination light beam is smaller than that of the area corresponding to the incident light beam; and the silicon-based liquid crystal spatial light modulator is used for modulating the illumination light beam according to the image information of the image to be projected so as to obtain the image light to be projected. The invention can prolong the service life of the projection system.

Description

Projection system and projection control method

Technical Field

The invention relates to the technical field of projection display, in particular to a projection system and a projection control method.

Background

A Liquid Crystal on Silicon (LCoS) chip Display technology is a micro-Display technology combining a semiconductor technology and a Liquid Crystal Display (LCD) technology.

However, since the liquid crystal and Polyimide (PI) alignment layers in the chip of the liquid crystal-on-silicon spatial light modulator may generate radicals under strong illumination conditions, the interaction of the radicals changes the surface energy of the polyimide and causes the orientation of the liquid crystal not to meet the pre-design conditions of the device, thereby causing the loss of the spatial light modulation function of the liquid crystal-on-silicon spatial light modulator, causing the life of the liquid crystal-on-silicon spatial light modulator to be shortened, and further causing the product life of the whole projection system to be shortened.

Disclosure of Invention

In order to solve the problem that the service life of a silicon-based liquid crystal spatial light modulator is short in the existing projection system based on the silicon-based liquid crystal spatial light modulator technology, the invention provides a projection system and a projection control method so as to prolong the service life of the silicon-based liquid crystal spatial light modulator.

A first aspect of the invention provides a projection system comprising light source means for forming an incident light beam, the projection system further comprising: the illumination light modulator is used for modulating the received incident light beams according to the brightness distribution information of the image to be projected so as to obtain illumination light beams, and the brightness of at least one area of each illumination light beam is smaller than that of the area corresponding to the incident light beam;

and the silicon-based liquid crystal spatial light modulator is used for modulating the illumination light beam according to the image information of the image to be projected so as to obtain the image light to be projected.

A second aspect of the present invention provides a projection control method applied to a projection system including a light source device for forming an incident light beam, the method comprising:

controlling an illumination light modulator to modulate a received incident light beam according to brightness distribution information of an image to be projected so as to obtain an illumination light beam, wherein the brightness of at least one area of the illumination light beam is smaller than that of an area corresponding to the incident light beam;

and controlling the silicon-based liquid crystal spatial light modulator to modulate the illumination light beam according to the image information of the image to be projected so as to obtain the image light to be projected.

Compared with the prior art, in the projection system, the provided illumination light modulator modulates according to the brightness distribution information of an image to be projected to obtain the illumination light beam, and the brightness of at least one area of the illumination light beam is smaller than that of the area corresponding to the incident light beam, so that the reduction of the light intensity of the incident light beam is realized, and the first-stage modulation is completed. And then, the provided silicon-based liquid crystal spatial light modulator modulates the illumination light beam according to the image information of the image to be projected to obtain the image light to be projected, and completes the secondary modulation. The illumination light beams are illumination light obtained by relatively weakening the light intensity of the incident light beams, so that the intensity of light received by the silicon-based liquid crystal spatial light modulator can be reduced, and the service life of the silicon-based liquid crystal spatial light modulator can be prolonged.

Further, since the illumination light beam emitted from the illumination light modulator can be dynamically adjusted, imaging of a high dynamic range image can be realized.

Drawings

Fig. 1 is a flowchart of a projection control method according to an embodiment of the present invention.

FIG. 2 is a schematic view of a projection system according to an embodiment of the invention.

FIG. 3 is a schematic view of a projection system according to an embodiment of the invention.

Fig. 4-6 are schematic structural diagrams of the color wheel according to various specific application examples provided by the present invention.

Fig. 7 is a schematic diagram of an image to be projected according to the present invention.

FIG. 8 is an illumination light pattern of FIG. 7 modulated by an illumination light modulator to produce an image to be projected.

Fig. 9 is an effect diagram of image light to be projected obtained by compensation-modulating an illumination light beam corresponding to the illumination light modulation pattern in fig. 8.

FIG. 10 is a schematic view of a projection system according to another embodiment of the present invention.

Description of the main elements

Projection system

100, 200, 300

Illumination light modulator 11

Liquid crystal on silicon

spatial light modulator

12, 209, 309

Yellow-transmitting and blue-reflecting

mirror

201, 301

Phosphor color wheel

202, 302

Thin film transistor liquid crystal chip 203

First mirror

204, 306

Polarizers 205, 305

Second reflecting mirror 206

Light combiners 207, 307

Lens relay lenses

210, 310

Polarization splitting prism 208

First polarization beam splitter prism 303

Second polarization beam splitter prism 308

Low resolution liquid crystal on silicon spatial light modulator 304

The following detailed description will further illustrate the invention in conjunction with the above-described figures.

Detailed Description

Referring to fig. 1, fig. 1 is a flowchart of a projection control method according to a preferred embodiment of the invention, which can be applied to a projection system or a device including the projection system, such as a liquid crystal on silicon micro laser projection, a liquid crystal on silicon laser television, and the like. It should be noted that the projection control method according to the embodiment of the present invention is not limited to the steps and the sequence in the flowchart shown in fig. 1. Steps in the illustrated flowcharts may be added, removed, or changed in order according to various needs.

As shown in fig. 1, the projection control method of the present embodiment may include the steps of:

step 101: and controlling an illumination light modulator to modulate the received incident light beam according to the brightness distribution information of the image to be projected so as to obtain an illumination light beam, wherein the brightness of at least one area of the illumination light beam is smaller than that of the area corresponding to the incident light beam.

In this embodiment, the incident light beam is formed by a light source device of the projection apparatus. The illumination light modulator determines modulation data from image information of an image to be projected, which may include an illumination light modulation pattern. The illumination light modulation pattern may be a pattern in which brightness distribution information of an image to be projected is loaded on a preset pattern. The preset pattern may include a dark region and a non-dark region, each image region obtained by the image to be projected in a preset division manner corresponds to each non-dark region in the preset pattern, and if a luminance value of the image region in the image to be projected is lower than a preset luminance value, the non-dark region corresponding to the image region is converted into the dark region to obtain the illumination light modulation pattern.

It is understood that the effect of transforming the non-dark regions corresponding to the image region into the dark regions is that the brightness of at least one region of the illumination beam is less than the brightness of the corresponding region of the incident beam, and the number of transformed regions is the same as the number of regions less than the brightness of the incident beam region.

In this embodiment, the brightness distribution information of the image to be projected may be obtained by performing brightness statistics on each image region based on each image region obtained by dividing the image to be projected in a preset dividing manner, where the brightness statistics manner may include obtaining a brightness average value in each image region, or obtaining a maximum brightness value in each image region, or obtaining a minimum brightness value in each image region.

In this embodiment, the preset dividing manner may include: 1) under the preset resolution of the image to be projected, one pixel point is an image area; 2) and dividing the image to be projected by the positions of the pixel points under the preset resolution, wherein an image block formed by a plurality of adjacent pixel points is an image area.

Corresponding to a preset division mode 1), wherein one non-dark area of the preset pattern corresponds to one pixel point; corresponding to the preset division mode 2), one non-dark area of the preset pattern corresponds to one image block. Therefore, when the brightness value of the pixel point or the image block is lower than the preset brightness value, the non-dark area corresponding to the pixel point or the image block can be converted into the dark area, and a Local dimming (Local dimming) effect is realized, so that the preset pattern obtains the illumination light modulation pattern due to the loading of the brightness information of the image to be projected, that is, the image information described by the pixel point/the image block corresponding to the original non-dark area is removed, and correspondingly, the emergent light corresponding to the part is eliminated, so that the light intensity of the illumination light beam irradiated to the silicon-based liquid crystal spatial light modulator is reduced, and the service life of the subsequent silicon-based liquid crystal spatial light modulator is further prolonged.

In this embodiment, the illumination light modulator may be any one of the following:

thin Film Transistor Liquid Crystal chips (FTF-LCDs), High Temperature polysilicon Liquid Crystal chips (HTPS LCDs), reflective low-resolution Silicon-based Liquid Crystal spatial light modulators (LCoS), and reflective Digital micromirror modulators (DMDs). The thin film transistor liquid crystal chip and the high-temperature polycrystalline silicon liquid crystal display chip are both transmission-type light modulators.

Step 102: and controlling the silicon-based liquid crystal spatial light modulator to modulate the illumination light beam according to the image information of the image to be projected so as to obtain the image light to be projected.

In this embodiment, the image information of the image to be projected is a description of information reflecting the image, so that the liquid crystal on silicon spatial light modulator can modulate the received illumination light with the corresponding color into the image light with the corresponding color according to the information, specifically, a modulation signal adapted to the liquid crystal on silicon spatial light modulator can be obtained according to the image information of the image to be projected, and the orientation of the liquid crystal in the liquid crystal on silicon spatial light modulator is controlled according to the modulation signal, so as to control the polarization state of the light beam which is irradiated on the reflective layer of the liquid crystal on silicon spatial light modulator and reflected by the illumination light beam, thereby generating the pixilated image light.

It can be understood that the image light to be projected is a projection picture which can be presented on the corresponding light receiving surface through the projection lens, and the image content of the image to be projected is consistent.

In this embodiment, the illumination light modulator is controlled to perform modulation according to the brightness distribution information of the image to be projected to obtain the illumination light beam, and the brightness of at least one area of the illumination light beam is smaller than the brightness of the area corresponding to the incident light beam, so as to reduce the light intensity of the incident light beam, thereby completing the first-stage modulation. And then, controlling the silicon-based liquid crystal spatial light modulator to modulate the illumination light beam according to the image information of the image to be projected so as to obtain the image light to be projected, and finishing the secondary modulation. The illumination light beams are illumination light obtained by relatively weakening the light intensity of the incident light beams, so that the intensity of light received by the silicon-based liquid crystal spatial light modulator can be reduced, and the service life of the silicon-based liquid crystal spatial light modulator can be prolonged.

Further, since the illumination light beam emitted from the illumination light modulator can be dynamically adjusted, an image display of a high dynamic range image can be supported.

In this embodiment, in order to restore the image to be projected to a certain extent in brightness of the image light to be projected after the secondary modulation, a compensation modulation pattern of the liquid crystal on silicon spatial light modulator may be determined according to the modulation data of the illumination light modulator, and the liquid crystal on silicon spatial light modulator performs compensation modulation on the illumination light beam according to the compensation modulation pattern so as to make the light quantity of the image light to be projected equal to the light quantity of the incident light beam.

In this embodiment, the compensation modulation data includes modulating the light amount of the image light to be projected by changing the on-time of the liquid crystal on silicon spatial light modulator.

Referring to fig. 2, fig. 2 is a schematic view of a projection system according to an embodiment of the invention. As shown in fig. 2, the projection system 100 includes an illumination light modulator 11 and a liquid crystal on silicon spatial light modulator 12, where the illumination light modulator 11 modulates an incident light beam according to brightness distribution information of an image to be projected to obtain a corresponding illumination light beam after receiving the incident light beam, and the brightness of at least one area of the illumination light beam is smaller than the brightness of an area corresponding to the incident light beam.

The brightness distribution information of the image to be projected is information obtained by performing brightness statistics on each image region obtained by the image to be projected according to a preset dividing mode, and specifically, the corresponding information can be obtained through the preset dividing mode and the brightness statistics mode, which is not described herein again.

It will be appreciated that the illumination light modulator 11 determines modulation data, which may comprise an illumination light modulation pattern, from the image information of the image to be projected. The illumination light modulation pattern may be a pattern in which brightness distribution information of an image to be projected is loaded on a preset pattern. The preset pattern may include a dark region and a non-dark region, each image region obtained by the image to be projected in a preset division manner corresponds to each non-dark region in the preset pattern, and if a luminance value of the image region in the image to be projected is lower than a preset luminance value, the non-dark region corresponding to the image region is converted into the dark region to obtain the illumination light modulation pattern. And under the condition that no information is loaded, corresponding each non-dark area in the preset pattern to each image area in the image to be projected. Thus, when loading the luminance information of the image to be projected: if the brightness value in the image area is lower than the preset brightness value, converting the non-dark area in the preset pattern corresponding to the image area into a dark area. It should be understood that in the specific modulation, the above processing can be performed on a plurality of image areas at the same time, and the processing speed should be greater than the frame rate of the image to be projected. Here, the preset brightness value may be adjusted according to the situation and the requirement.

It is understood that the incident light beam is preferably a three-primary-color light beam, which may be any one of three primary-color light beams, and may be a laser beam directly generated by a laser, a fluorescent light beam emitted after a fluorescent powder layer is excited, or a light beam emitted by a light emitting diode. For three primary color light beams, the projection system in this embodiment may include two illumination light modulators or three illumination light modulators, each of which may modulate one or two primary color light beams to generate a corresponding color illumination light beam.

In this embodiment, the illumination light beam emitted from the illumination light modulator 11 is received by the liquid crystal on silicon spatial light modulator 12, and the liquid crystal on silicon spatial light modulator 12 modulates the illumination light beam according to the image information of the image to be projected, so as to obtain the image light to be projected.

It is understood that the projection system 100 of this embodiment may include a single-chip liquid crystal on silicon spatial light modulator, and may also include a multi-chip liquid crystal on silicon spatial light modulator. Under the condition that a single-chip silicon-based liquid crystal spatial light modulator modulates the illumination light beams of three primary colors, the illumination light beams of all colors can be modulated according to time sequence to obtain image light to be projected of corresponding colors output according to the time sequence, and after the image light is projected, a color image can be synthesized on senses by utilizing the persistence of vision effect of human eyes. Of course, the liquid crystal on silicon spatial light modulator 12 may modulate only the illumination light beam of one primary color, so that the projection system may be provided with three liquid crystal on silicon spatial light modulators to modulate the corresponding illumination light beams, for example, one liquid crystal on silicon spatial light modulator modulates the blue illumination light, and the other two liquid crystal on silicon spatial light modulators modulate the red illumination light and the green illumination light, that is, the illumination light beam of one color is modulated by one liquid crystal on silicon spatial light modulator.

In an expanded application example of the present embodiment, the incident light beam is a first color light beam of the three primary color light beams, and correspondingly, the illumination light modulator 11 modulates the received first color light beam to obtain a first illumination light beam. It will be appreciated that the color of the first illumination beam at this time is still the first color.

In the present extended application example, the projection system 100 may further include, in addition to the illumination light modulator 11 and the liquid crystal on silicon spatial light modulator 12, a first optical path component for guiding a second illumination light beam and a third illumination light beam of three primary color lights, and the first illumination light beam, the second illumination light beam and the third illumination light beam are respectively three primary color illumination light beams with different colors, so as to support the projection of a color image.

Further, in this expanded application example, the projection system 100 may further include a laser light source and a color wheel, where the color wheel is configured to process a laser beam emitted from the laser light source to obtain the first color beam, the second color beam, and the third color beam, and of course, the first color beam, the second color beam, and the third color beam here are three primary color lights with different colors. The color wheel may include three regions, namely a first region, a second region and a third region, where the first region, the second region and the third region are periodically disposed on a beam propagation path of laser light to generate the first color beam, the second color beam and the third color beam in a time sequence. Accordingly, the second color light beam and the third color light beam may be processed to obtain the corresponding second light beam and third light beam, for example, the polarizer may be used to perform polarization conversion processing on the second color light beam to obtain the second light beam, and similarly, the polarizer may be used to perform polarization conversion processing on the third color light beam to obtain the third light beam. Here, the first color light beam may be a blue light beam, the second color light beam may be a red light beam, and the third color light beam may be a green light beam. After the corresponding processing, the blue light beam is modulated into a blue light illumination beam with lower brightness, namely a first illumination beam; the red light beam is converted into a red light beam with linear polarization, namely a second light beam; the green light beam is converted into a green light beam having linear polarization, i.e., a third light beam.

Specifically, the first region may be a reflection region that reflects the first color light beam or a transmission region that transmits the first color light beam, and the second region may be a light conversion region of the second color light beam, and the third region may be a light conversion region of the third color light beam.

It is understood that the purpose of defining the light of three primary colors herein is to satisfy the color vision requirement in most cases, and therefore, in the practical application process, any one of three primary colors, multiple colors or other composite colors besides the three primary colors can be selected, on the basis of which, the illumination light modulator 11 and the liquid crystal on silicon spatial light modulator 12 can obtain the projection image of a specific color, and since the illumination light beam generated by the illumination light modulator 11 is a light beam with relatively reduced average brightness, the service life of the liquid crystal on silicon spatial light modulator 12 can be prolonged.

In another extended application example of the present embodiment, the incident light beam may also include a first color light beam, and the illumination light modulator 11 may be configured to modulate the received first color light beam to obtain a first illumination light beam including an illumination pattern. Compared with the previous expansion application example, the difference is that: the projection system 100 in this expanded application example may include two liquid crystal on silicon spatial light modulators, and the projection system may further include a light combiner and a second light path component for conducting a second light beam and a third light beam of three primary color lights, where the first illumination light beam, the second light beam, and the third light beam are three primary color light beams with different colors.

And the other silicon-based liquid crystal spatial light modulator is used for modulating the second light beam and the third light beam according to the image information of the image to be projected so as to obtain the monochromatic image light to be projected of the second color and the monochromatic image light to be projected of the third color in time sequence.

In another extended application example of the present embodiment, the incident light beam may also include a first color light beam, and the illumination light modulator 11 is configured to modulate the received first color light beam to obtain a first illumination light beam. Compared with the expansion application example, the difference is that: the projection system in this expanded application example includes three liquid crystal on silicon spatial light modulators, and the projection system may further include a light combiner and a third light path component for conducting a second light beam and a third light beam of the three primary color lights, where the first illumination light beam, the second light beam, and the third light beam are three primary color light beams with different colors.

The at least one silicon-based liquid crystal spatial light modulator comprises three silicon-based liquid crystal spatial light modulators, and each silicon-based liquid crystal spatial light modulator is used for modulating the corresponding first illumination light beam, the second light beam and the third light beam according to the image information of the image to be projected so as to obtain monochromatic image light to be projected of a first color, monochromatic image light to be projected of a second color and monochromatic image light to be projected of a third color. It can be understood that when monochromatic lights of all colors modulated by three LCOS spatial light modulators are subjected to light combination processing and projected to the same plane, corresponding color projection images can be synthesized.

In this embodiment, in combination with the above extended application example, it can be understood that, for a single-silicon-based liquid crystal spatial light modulator and a multi-silicon-based liquid crystal spatial light modulator, it is beneficial to prolong the service life of the silicon-based liquid crystal spatial light modulator and to correlate the number of the illumination light modulators, that is to say: when the projection system comprises the illumination light modulator and the single-silicon-based liquid crystal spatial light modulator, the light intensity of the illumination light beam obtained by modulation of the illumination light modulator can be relatively reduced, so that the service life of the single-silicon-based liquid crystal spatial light modulator is prolonged; when the projection system includes two or more illumination light modulators, if the silicon-based liquid crystal spatial light modulators corresponding to the number of the illumination light modulators are provided, and each illumination light modulator and each silicon-based liquid crystal spatial light modulator are only responsible for the modulation of the corresponding three primary color light beams, the light intensity of the illumination light beams obtained by the modulation of each illumination light modulator can be relatively reduced, thereby being beneficial to prolonging the service life of the corresponding silicon-based liquid crystal spatial light modulator.

It can be understood that, when the illumination light modulator 11 modulates the received light beam, if the preset brightness value is set to be larger, the amplitude of reduction of the light intensity of the obtained illumination light beam is larger after the brightness distribution information of the image to be projected is loaded, which is further beneficial to prolonging the service life of the liquid crystal on silicon spatial light modulator.

In this embodiment, the resolution of the illumination light modulator 11 is smaller than that of the liquid crystal on silicon spatial light modulator 12, which is beneficial to saving cost.

In the present embodiment, the temporal response of the illumination light modulator 11 is not lower than the frame rate of the image to be projected.

In this embodiment, the provided illumination light modulator performs modulation according to brightness distribution information of an image to be projected to obtain an illumination light beam, and the brightness of at least one area of the illumination light beam is smaller than the brightness of an area corresponding to the incident light beam, so as to reduce the light intensity of the incident light beam, thereby completing the first-stage modulation. And then, the provided silicon-based liquid crystal spatial light modulator modulates the illumination light beam according to the image information of the image to be projected to obtain the image light to be projected, and completes the secondary modulation. The illumination light beams are illumination light obtained by relatively weakening the light intensity of the incident light beams, so that the intensity of light received by the silicon-based liquid crystal spatial light modulator can be reduced, and the service life of the silicon-based liquid crystal spatial light modulator can be prolonged.

Referring to fig. 3, fig. 3 is a schematic view of a projection system according to an embodiment of the invention. The illumination light modulator of the present embodiment is a thin film transistor liquid crystal chip 203, and specifically, the light source device of the projection system 200 of the present embodiment may include a yellow-transmitting and blue-reflecting mirror 201, a phosphor color wheel 202, a thin film transistor liquid crystal chip 203, and a polarizer 205. It should be understood that the yellow-transparent and blue-reflective mirror 201 can be replaced by other light guiding devices, such as a blue-transparent and blue-reflective mirror, etc., with appropriate adjustment of the light path.

The light source of the light source device is a blue laser light source for emitting a blue laser beam, and the blue laser beam is reflected to the fluorescent powder color wheel 202 after being reflected by the yellow-transmitting and blue-reflecting mirror 201. The phosphor color wheel 202 may include a first region, a second region and a third region, and the phosphor color wheel 202 is configured to generate a red light beam, a green light beam and a blue light beam in time sequence under the excitation of the blue laser beam.

Fig. 4 to fig. 6 are schematic diagrams of each specific actual structure of the phosphor color wheel in the present embodiment. As shown in fig. 4, the a region in the phosphor color wheel is the first region, and the regions respectively disposed at both sides of the a region are a red light conversion region and a green light conversion region, where the red light conversion region is the second region and the green light conversion region is the third region.

When the blue laser beam irradiates the area A, the area A converts the received blue laser beam into a blue light beam; when the blue laser beam irradiates the red light conversion area, the red light conversion area converts the received blue laser beam into a red light beam; the green conversion area converts the received blue laser beam into a green beam while the blue laser is irradiated on the green conversion area.

It can be understood that, since the converted blue light beam has no linear polarization, the subsequent process needs to be performed by disposing a corresponding polarizer to perform the polarized light conversion process.

In this embodiment, the region a may also be a scattering region for performing a light scattering effect on the received blue laser beam, and the polarization characteristic of light may not be changed in the light scattering effect process.

As shown in fig. 5, the a region in the phosphor color wheel is also the first region, and the regions respectively disposed at two sides of the a region are the red light conversion region and the green light conversion region, which are different from the structure of the phosphor color wheel in fig. 4 in that: the area a is a transmission area for the blue laser beam irradiated onto the color wheel to directly pass through to obtain a blue laser beam.

As shown in fig. 6, the a region in the phosphor color wheel is the first region, and the regions respectively disposed at two sides of the a region are a red light conversion region and a green light conversion region, which are different from the phosphor color wheel structures in fig. 4 and 5 in that: the area a is a reflection area for reflecting the blue laser beam irradiated onto the fluorescence wheel to obtain the blue laser beam. It is understood that the reflection angle of the blue laser beam irradiated onto the phosphor wheel can be controlled by the angle of the reflection surface on the phosphor wheel, and thus, the arrangement position and the optical path arrangement of the phosphor wheel and other optical elements can be made more flexible.

Referring to fig. 3, the first region in the phosphor color wheel 202 in fig. 3 is a reflection region, so that the blue laser beam can be emitted to the tft liquid crystal chip 203 under the reflection action of the phosphor color wheel 202, and the tft liquid crystal chip 203 modulates the blue laser beam according to the brightness distribution information of the image to be projected to obtain the blue illumination beam. The generated blue illumination beam is reflected by the first mirror 204. Here, a microstructure for eliminating laser coherence may be further disposed in the first region, so as to reduce the influence of speckle brought by the blue laser beam on the display. Of course, the tft liquid crystal chip 203 may be replaced by a high temperature polysilicon liquid crystal chip or a digital micromirror modulator, and the resolution of the tft liquid crystal chip, the high temperature polysilicon liquid crystal chip or the digital micromirror modulator may preferably be a low resolution device, so as to reduce the cost of the projection system; the response rate of the thin film transistor liquid crystal chip, the high-temperature polysilicon liquid crystal chip or the digital micromirror modulator is higher than the frame rate of the image to be projected, and the corresponding rate of the thin film transistor liquid crystal chip, the high-temperature polysilicon liquid crystal chip or the digital micromirror modulator is as high as possible on the basis of considering relative cost so as to reduce the probability of the phenomenon of smearing of the projection image.

It is understood that when the tft-lcd chip 203 is replaced with a dmd, the reflective property of the dmd can be directly used to modulate and reflect the corresponding light beam, and the first mirror 204 can be omitted.

It can be understood that, after the blue illumination beam obtained by the reflection action of the phosphor color wheel 202, the blue illumination beam can be compensated by using a cylindrical lens to reduce the curvature influence caused by the phosphor color wheel 202.

Meanwhile, the red light beam and the green light beam generated by the phosphor color wheel 202 are transmitted by the yellow-transmitting and blue-reflecting mirror 201 and then emitted to the position of the polarizer 205, and the polarizer 205 is used for performing polarized light conversion processing on the red color light beam and the green color light beam to obtain the red light beam and the green light beam both having linear polarization. It is understood that the red color light beam and the green color light beam generated by the phosphor color wheel 202 are unpolarized light, and thus the red color light beam and the green color light beam can be converted into linearly polarized light by the polarizer 205. Thereafter, the red light beam and the green light beam are reflected by a second mirror 206 to reflect the red light beam and the green light beam to a light receiving surface side of a Polarizing Beam Splitter (PBS) 208. Here, the red light beam, the green light beam, and the blue light beam that are not subjected to the polarization conversion process are all beams having the first polarization state.

The polarization beam splitter prism 208 is disposed on a light incident surface side of the liquid crystal on silicon spatial light modulator 209, and is configured to reflect a received light beam with a first polarization state to be reflected into the liquid crystal on silicon spatial light modulator 209, and then transmit a light beam with a second polarization state obtained by performing polarization deflection modulation on the liquid crystal on silicon spatial light modulator 209. Wherein the first polarization state is S polarization state, and the second polarization state is P polarization state; of course, the first polarization state may be P polarization state, and the second polarization state may be S polarization state.

In this embodiment, the polarizer 205 may be a linear polarizer or a Polarization Conversion System (PCS) composed of a polarization splitting prism and a wide-spectrum half glass. As in the case of the polarizer 205 being a polarization conversion system, in the deflected light conversion process: after the red color light beam enters the polarization beam splitting prism, one part of the red color light beam directly transmits to the wide-spectrum half-wave plate through one light path, the other part of the red color light beam is reflected to the wide-spectrum half-wave plate through the second time in the other light path, and the light emergent direction of the red color light beam emitted to the wide-spectrum half-wave plate through one light path is parallel to the light emergent direction of the red color light beam emitted to the wide-spectrum half-wave plate through the other light path. Thereafter, the incident red light beam is deflected by 90 degrees by the broad spectrum half-wave plate, and the two portions of the red color light beam are kept parallel to obtain the red light beam.

It is understood that, if it is preferable that the linear polarization of the blue light illumination beam is matched with the incident polarization of the polarization splitting prism, it is advantageous to improve the utilization efficiency of the blue light illumination beam.

The light combiner 207 receives the red light beam and the green light beam reflected by the second reflecting mirror 206 and the blue light illumination beam reflected by the first reflecting mirror 204, so as to guide the three primary color light beams to the same optical path for transmission, and transmit the light beams to the polarization beam splitter 208 for reflection, so that the liquid crystal on silicon spatial light modulator 209 receives the corresponding light beams. The liquid crystal on silicon spatial light modulator 209 modulates the red light beam, the green light beam, and the blue light illumination beam according to the image information of the image to be projected, thereby obtaining corresponding image light to be projected. The image light to be projected can be relayed and transmitted by the lens relay lens 210 and finally emitted by the projection lens to obtain a projection picture.

It can be understood that, through the arrangement of the thin film transistor liquid crystal chip, the illumination light beam with light intensity can be relatively reduced, so that the illumination intensity of the light beam irradiating the silicon-based liquid crystal spatial light modulator can be indirectly reduced, and the service life of the silicon-based liquid crystal spatial light modulator can be prolonged.

In this embodiment, the liquid crystal on silicon spatial light modulator may have a certain difference in modulation patterns of illumination light beams of different colors in the same image frame to be projected. Since the thin film transistor liquid crystal chip is used to modulate the blue light in this embodiment, the modulation pattern corresponding to the blue light beam is a compensation pattern relatively determined according to the illumination pattern of the thin film transistor liquid crystal chip.

In this embodiment, the response frequency of the liquid crystal on silicon spatial light modulator is greater than three times the response rate of the low-resolution liquid crystal on silicon spatial light modulator, for example, when the response rate of the low-resolution liquid crystal on silicon spatial light modulator is greater than 60Hz, the response rate of the high-resolution liquid crystal on silicon spatial light modulator here is greater than 180 Hz.

In the embodiment, because the better linear polarization of the laser is utilized, a corresponding polarizer is not required to be arranged for the light path for processing the blue light beam, and the cost and the structural complexity of the projection system are favorably reduced.

Referring to fig. 7 to 9, fig. 7 is a schematic diagram of an image to be projected according to the present invention; FIG. 8 is a modulation pattern of light using an illumination light modulator to modulate the image to be projected of FIG. 7; fig. 9 is an effect diagram of image light to be projected obtained by compensation-modulating the illumination light beam corresponding to the modulation pattern in fig. 8.

The modulation pattern in fig. 8 is generated by performing brightness statistics on the image to be projected in fig. 7, and after the modulation pattern is determined, the liquid crystal on silicon spatial light modulator performs polarization deflection pixelization modulation on the light beam having the first polarization state according to the modulation pattern.

It can be understood that the brightness of the image light obtained by the modulation of the modulation pattern is usually darker than that of the image to be projected, and therefore, the image obtained by the modulation can also be subjected to compensation modulation, while in the present embodiment, the blue illumination light beam is modulated, and therefore, only the modulation pattern corresponding to the blue light can be subjected to compensation modulation.

As shown in fig. 9, the effect diagram is obtained by performing compensation modulation on the illumination beam by the silicon-based liquid crystal spatial light modulator. The image shown in fig. 9 is the superposition of the image light after the compensation modulation of the blue light and the image light formed after the modulation of the red light beam and the green light beam, and the overall visual effect of the image is brighter.

It will be appreciated that the LCOS spatial light modulator may determine a compensation modulation pattern based on the modulation data of the illumination light modulator, i.e., after determining the modulation pattern of FIG. 8, the compensation modulation pattern is relatively determined. The compensation pattern may make the resulting light quantity of the image light to be projected equal to the light quantity of the incident light beam, that is, such that: the brightness of the image light to be projected which is emitted by the silicon-based liquid crystal spatial light modulator subjected to compensation modulation is consistent with the brightness of the image light to be projected which is emitted by the silicon-based liquid crystal spatial light modulator which is not provided with the illumination light modulator for modulation and is not subjected to compensation modulation, so that the brightness is restored to the brightness of the image to be projected to a certain extent.

In this embodiment, the compensation modulation data includes modulating the light quantity of the image light to be projected by changing the on-time of the liquid crystal on silicon spatial light modulator, that is, increasing the on-time to increase the product of the displayed light flux and time, thereby increasing the light quantity.

Referring to fig. 10, fig. 10 is a schematic view of a projection system according to another embodiment of the present invention. The projection system 300 receives the blue laser beam, and reflects the blue laser beam to the phosphor color wheel 302 after being reflected by the yellow-transmitting and blue-reflecting mirror 301. The structure of the phosphor color wheel 302 may be the same as the structure of the phosphor color wheel 302 shown in fig. 3, and thus, will not be further described herein.

In this embodiment, the first region in the phosphor color wheel 302 is a reflection region, so that the blue laser beam can be emitted to the first polarization splitting prism 303 under the reflection action of the phosphor color wheel 302. The first polarization beam splitter prism 303 reflects the received blue laser beam to the low-resolution liquid crystal on silicon spatial light modulator 304, and the low-resolution liquid crystal on silicon spatial light modulator 304 modulates the blue laser beam according to the brightness distribution information of the image to be projected to obtain a blue illumination beam. Here, a microstructure for eliminating laser coherence may be further disposed in the first region, so as to reduce the influence of speckle brought by the blue laser beam on the display.

Meanwhile, the red light beam and the green light beam generated by the phosphor color wheel 302 are transmitted by the yellow-transmitting and blue-reflecting mirror 301 and then emitted to the polarizer 305, and similarly, the polarizer 305 is used for performing polarization conversion processing on the red color light beam and the green color light beam to obtain the corresponding red light beam and green light beam. The red light beam and the green light beam are reflected by the first reflecting mirror 306 to reflect the red light beam and the green illumination beam to the optical path of the light combiner 307.

The light combiner 307 receives the red light beam and the green light beam reflected by the first reflecting mirror 306 and the blue light illumination beam emitted by the low-resolution liquid crystal on silicon spatial light modulator 304, so as to guide the three primary color light beams to the same light path for conduction, and conduct the light beam to the second polarization beam splitter 308, and then reflect the red light beam, the green light beam and the blue light beam with the first polarization state to the liquid crystal on silicon spatial light modulator 309 through the second polarization beam splitter 308. The liquid crystal on silicon spatial light modulator 309 modulates the red light beam, the green light beam, and the blue light illumination beam according to the image information of the image to be projected, so as to obtain the corresponding image to be projected, and the liquid crystal on silicon spatial light modulator 309 also modulates the polarization deflection of the received light beam, so that the emitted light beam is the light beam with the second polarization state (i.e., the image to be projected), and is transmitted by the second polarization splitting prism 308. In this embodiment, the first polarization state is S polarization state, and the second polarization state is P polarization state; of course, the first polarization state may be P polarization state, and the second polarization state may be S polarization state. Finally, the image light to be projected can be relayed and transmitted by the lens relay lens 310 and finally emitted by the projection lens to obtain a projection picture.

The above description is only an embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes, which are made by using the contents of the present specification and the accompanying drawings, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.

Claims

1. A projection system comprising a light source device for forming an incident light beam, characterized in that the projection system further comprises:

the illumination light modulator is used for modulating the received incident light beams according to the brightness distribution information of the image to be projected so as to obtain illumination light beams, and the brightness of at least one area of each illumination light beam is smaller than that of the area corresponding to the incident light beam;

2. The projection system according to claim 1, wherein the luminance distribution information of the image to be projected is information obtained by performing luminance statistics on each image region obtained by dividing the image to be projected in a predetermined manner.

3. The projection system of claim 1 wherein the liquid crystal on silicon spatial light modulator determines corresponding compensation modulation data based on the modulation data of the illumination light modulator to perform compensation modulation on the illumination light beam using the compensation modulation data.

4. The projection system of claim 3, wherein the compensating modulation data comprises modulating the amount of image light to be projected by changing an on-time of the liquid crystal on silicon spatial light modulator.

5. The projection system of claim 1, wherein the incident light beams comprise a first color light beam, a second color light beam and a third color light beam, and the first color light beam, the second color light beam and the third color light beam are respectively three primary colors of light with different colors;

the illumination light modulator is used for modulating the received first color light beam according to the brightness distribution information of the image to be projected so as to obtain a first illumination light beam;

the liquid crystal on silicon spatial light modulator is used for modulating the first illumination light beam, the second color light beam and the third color light beam respectively according to image information of an image to be projected so as to obtain the image light to be projected.

6. The projection system of claim 5, wherein the light source device further comprises a laser light source and a color wheel, the color wheel being configured to convert a laser beam emitted by the laser light source to generate the first color beam, the second color beam, and/or the third color beam.

7. The projection system of claim 6, wherein when the color wheel is used to convert the laser beam emitted from the laser light source to generate the first color beam, the second color beam, and the third color beam, the color wheel includes a first region, a second region, and a third region, and the first region, the second region, and the third region are periodically disposed on a path along which the laser beam propagates to generate the first color beam, the second color beam, and the third color beam in a time sequence;

the first region is a reflection region that reflects the first color light beam or a transmission region that transmits the first color light beam, the second region is a light conversion region of the second color light beam, and the third region is a light conversion region of the third color light beam.

8. The projection system of claim 7, wherein the laser light source emits a blue laser beam;

the first region reflects the blue laser beam; the second area converts the blue laser beam to obtain a red light beam, and the third area converts the blue laser beam to obtain a green light beam.

9. The projection system of claim 8, wherein the projection system further comprises a polarizer, the polarizer is used for carrying out polarized light conversion processing on the red light beams and the green light beams to obtain the red light beams and the green light beams which both have a first polarization state, the projection system also comprises a polarization beam splitter prism arranged on one side of the light incidence surface of the LCOS spatial light modulator, the polarization beam splitter prism is used for reflecting the received light beam with the first polarization state, transmitting the light beam with the second polarization state obtained after the polarization deflection modulation is carried out on the silicon-based liquid crystal spatial light modulator, the first polarization state is perpendicular to the polarization direction of the second polarization state, and the liquid crystal on silicon spatial light modulator performs polarization deflection modulation on the light beam with the first polarization state reflected by the deflection beam splitter prism.

10. The projection system of claim 9, further comprising a transflective blue mirror and a reflector, wherein the transflective blue mirror is disposed between the color wheel and the polarizer, and is configured to reflect the blue laser beam onto the color wheel and to conduct the red light beam and the green light beam generated by the color wheel;

the reflector is arranged between the polarizer and the silicon-based liquid crystal spatial light modulator and used for reflecting the red light beam and the green light beam to the silicon-based liquid crystal spatial light modulator.

11. The projection system of any of claims 1 to 10, wherein a resolution of the illumination light modulator is less than a resolution of the liquid crystal on silicon spatial light modulator.

12. The projection system of claim 11, wherein the response rate of the illumination light modulator is not lower than a frame rate of an image to be projected.

13. A projection control method for use in a projection system comprising a light source device for forming an incident light beam, the method comprising:

14. The projection control method according to claim 13, wherein the luminance distribution information of the image to be projected is information obtained by performing luminance statistics on each image region obtained by dividing the image to be projected in a preset division manner.