CN113138522B

CN113138522B - Light source modulation system, method and light source system

Info

Publication number: CN113138522B
Application number: CN202010050162.1A
Authority: CN
Inventors: 赵鹏; 吴超; 余新; 李屹
Original assignee: Appotronics Corp Ltd
Current assignee: Shenzhen Appotronics Corp Ltd
Priority date: 2020-01-17
Filing date: 2020-01-17
Publication date: 2023-08-04
Anticipated expiration: 2040-01-17
Also published as: WO2021143441A1; CN113138522A

Abstract

The application discloses a light source modulation system which comprises a first spatial light modulator, a light splitting element, a second spatial light modulator and a light combining element; the first spatial light modulator is used for modulating incident light source light to form first image light and generating OFF light; the light splitting element is configured to separate the first image light from the optical path of the OFF light, guide the first image light to the light combining element, and guide the OFF light to the second spatial light modulator; the second spatial light modulator modulates the OFF light to form second image light; the light combining element combines the first image light and the second image light. The OFF light generated by the first spatial light modulator is fully utilized, so that the image brightness is improved. Based on the light source modulation system, the application also discloses a light source modulation method, which can further improve the light energy utilization rate and the image brightness.

Description

Light source modulation system, method and light source system

Technical Field

The present disclosure relates to the field of projection technologies, and in particular, to a light source modulation system, a light source modulation method, and a light source system.

Background

There are two main methods for increasing the brightness of the projection screen, one is to directly increase the brightness of the light source itself, and the other is to increase the light utilization efficiency.

Directly increasing the brightness of the light sources themselves, including increasing the number of light sources, or increasing the brightness of individual light sources by increasing the current through the light sources, etc. However, the solution of directly increasing the brightness of the light source can increase the cost of the projector, and also increase the heat generated by the whole projector, resulting in an increase of heat dissipation pressure. Meanwhile, the increase of the brightness of the light source often leads to the increase of the optical expansion of the light source, and the optical expansion is limited by components such as a light machine, a modulator and the like in actual use, so that the upper limit also exists for increasing the brightness of the light source.

The light utilization efficiency is increased, and the light is roughly divided into two types, one is a light recycling scheme, and the rest of OFF light generated when an image is generated by a modulator is utilized to reuse the light energy, so that the light energy utilization efficiency is increased. The other is a light steering technology, light energy is rearranged according to brightness distribution of an image by using a pre-modulator, the light energy is converged in a highlight area in the image, and the utilization efficiency of the light energy is improved, so that a projection effect with higher brightness is achieved. However, the light steering technology relies on an additional pre-modulator, which increases the cost, and the current mainstream light steering technology is implemented by using a phase spatial light modulator, but the device is not mature at present and is not commercially applied on a large scale.

Disclosure of Invention

The application mainly provides a light source modulation system, a light source modulation method and a light source system, so that OFF light is recycled to increase light energy utilization efficiency and improve projection picture brightness.

In order to solve the technical problems, in one aspect, the present application provides a light source modulation system, including a first spatial light modulator, a light splitting element, a second spatial light modulator, and a light combining element; the first spatial light modulator is used for modulating incident light source light to form first image light and generating OFF light; the light splitting element is configured to separate the first image light from the optical path of the OFF light, guide the first image light to the light combining element, and guide the OFF light to the second spatial light modulator; the second spatial light modulator modulates the OFF light to form second image light; the light combining element combines the first image light and the second image light.

In one embodiment, the light source further comprises a light homogenizing element, wherein the light homogenizing element is arranged on a light path between the light splitting element and the second spatial light modulator and is used for homogenizing OFF light generated by the first spatial light modulator.

In one embodiment, the first spatial light modulator is an LCD panel with an analyzer removed; the second spatial light modulator is one of DMD, LCD, LCOS.

In one embodiment, the light splitting element and the light combining element multiplex the same PBS prism.

Further, the light modulation system further comprises a modulation function input module for controlling the modulation functions of the first spatial light modulator and the second spatial light modulator so as to minimize OFF light generated by the second spatial light modulator.

In another aspect, the present application further provides a light source modulation method, including: step S1: modulating light source light incident to the first spatial light modulator according to an image signal to generate first image light and OFF light; step S2: modulating OFF light incident to the second spatial light modulator according to the image signal to generate second image light; step S3: and combining the first image light and the second image light and outputting the combined light.

Further, the light source modulation method further includes, after step S2: step S21: obtaining the OFF luminance of light incident on the second spatial light modulator in the current pixel; step S22: judging whether the sum of the brightness of the first image and the brightness of the second image is larger than the OFF brightness incident on a second spatial light modulator; step S23: if the sum of the first image brightness and the second image brightness is greater than or equal to the OFF brightness incident on the second spatial light modulator, updating the second image brightness to the OFF brightness incident on the second spatial light modulator, and updating the first image brightness to the difference between the sum of the first image brightness and the second image brightness and the OFF brightness incident on the second spatial light modulator; step S24: if the sum of the first image brightness and the second image brightness is smaller than the OFF brightness incident to the second spatial light modulator, updating the second image brightness to the sum of the first image brightness and the second image brightness, and updating the first image brightness to zero; step S25: calculating an OFF light increment generated by the first spatial light modulator at the moment; step S26: calculating the OFF light increment incident to the second spatial light modulator according to the OFF light increment generated by the first spatial light modulator; step S27: modulating the OFF light increment incident to the second spatial light modulator according to an image signal to obtain incremental brightness; step S28: and updating the brightness of the second image to be the sum of the brightness of the second image and the increment brightness.

In one embodiment, further, step S29: judging whether a preset condition is met or not; if yes, repeating steps S21-S28.

In one embodiment, the preset condition includes: and the OFF light output by the second spatial light modulator is larger than a preset value.

In another embodiment, after the step S28, the method further includes: steps S21-S28 are repeated once.

Processing each sub-pixel in the image frame according to the method described above: calculating a first modulation function of a first spatial light modulator according to the first image brightness, and calculating a second modulation function of a second spatial light modulator according to the second image brightness; the first spatial light modulator modulates light source light according to the first modulation function, and the second spatial light modulator modulates light incident to the second spatial light modulator according to the second modulation function.

On the other hand, the application also provides a light source system which comprises a multicolor light source, wherein the light source with at least one color in the multicolor light source is modulated by adopting the light source modulation system and the light source modulation method.

In one embodiment, the polychromatic light source is a red, green and blue light source.

The beneficial effects of this application are: by adopting the dual-spatial light modulator light source modulation system provided by the application, the OFF light output by the first spatial light modulator is utilized again, the light energy utilization efficiency is improved, better picture display brightness can be realized on the premise of the same light source brightness, and meanwhile, because the OFF light is utilized for display, the heat generated by the OFF light is reduced, and the heat dissipation pressure of the whole machine is lightened.

In addition, by adopting the light source modulation method, on the basis of the light source modulation system, the OFF light generated by the second spatial light modulator can be reduced, and the light energy utilization rate is further improved.

Drawings

For a clearer description of embodiments of the present application or of the solutions of the prior art, the drawings that are required to be used in the description of the embodiments or of the prior art will be briefly described, it being apparent that the drawings in the description below are only some embodiments of the present application, and that other drawings may be obtained, without inventive effort, by a person skilled in the art from these drawings, in which:

FIG. 1 is a schematic illustration of the optical path of OFF light split for different spatial light modulators in the present application;

FIG. 2 is a schematic block diagram of the optical path of the light source modulation system of the present application;

FIG. 3 is a schematic diagram of an optical path of a first spatial light modulator, which is an LCD, and a second spatial light modulator, which is a DMD, in an embodiment of the present application;

FIG. 4 is a schematic diagram of an optical path of multiplexing a PBS when the first and second spatial light modulators are LCDs in an embodiment of the present application;

FIG. 5 is a schematic view of the light path of a light source system in one embodiment of the present application;

FIG. 6 is a schematic view of the light path of a light source system according to another embodiment of the present application;

FIG. 7 is a flow chart of a light source modulation method in a first embodiment of the present application;

FIG. 8 is a flow chart of a light source modulation method in a second embodiment of the present application;

9a/9b are exemplary diagrams of light source modulation in the present application;

fig. 10 is a schematic view of the brightness effect of an image using the light source modulation method of the present application.

Detailed Description

The following description of the technical solutions in the embodiments of the present application will be made clearly and completely with reference to the accompanying drawings in the embodiments of the present application, and it is apparent that the described embodiments are only some embodiments of the present application, not all embodiments. All other embodiments, which can be made by one of ordinary skill in the art without undue burden from the present disclosure, are within the scope of the present disclosure.

Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the present application. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Those of skill in the art will explicitly and implicitly appreciate that the embodiments described herein may be combined with other embodiments.

A spatial light modulator refers to an electro-optical device that can modulate a light beam, and is widely used in projection systems, and mainly includes three types, DMD, LCD, and Lcos. When using a spatial light modulator to generate a picture, the spatial light modulator modulates the incident uniform illumination light, so that the luminance portion of the generated picture enters a subsequent projection system, and the rest, called OFF light, is absorbed by the modulator or reflected in other directions to be absorbed by the light dump, as shown in fig. 1.

Fig. 1 (a) is a schematic diagram of an LCD device, 101 is a polarizer, specific beam polarization is provided, the polarization state of incident light 104 after passing through is guaranteed to meet the requirements of a subsequent device, 103 is a liquid crystal layer, the polarization state of the incident light 104 can be controlled differently by adding different voltages to the liquid crystal layer, so as to obtain two components of a beam 106 and a beam 105, the two components of the beam have different polarization states, 102 is an analyzer, the beam 106 with specific polarization can be filtered out to form image light, and the beam 105 filtered out by the analyzer, that is, OFF light corresponding to the LCD device, can be led out by removing the analyzer 102.

Fig. 1 (b) is a schematic diagram of a DMD device, 11 is a DMD,112 is a TIR prism commonly used with DMDs, incident light 114 enters from the side of TIR, image light 115 generated by the DMD exits from the front of TIR, OFF light 116 forms a certain angle with the image light, and OFF light processing is typically performed using an optical dump device 113.

Fig. 1 (c) is a schematic diagram of an LCOS device, 12 is an LCOS device, 132 is a PBS prism commonly used in conjunction with an LCOS, and incident light 133 has a p-polarization state, so that after entering the LCOS through the PBS, the incident light is changed in polarization state by the LCOS, and p-polarized 135 and s-polarized 134 are generated, and the 134 light is reflected by the PBS and becomes image light, while 135 is OFF light, and is transmitted back from the PBS to the incident light direction, when the incident light is perpendicular to the LCOS, the OFF light is opposite to the incident light direction, and is coincident in position, so that separation is difficult, and therefore, in order to spatially separate the OFF light from the incident light, the incident light and the LCOS can be set at an angle.

Referring to fig. 2, a schematic block diagram of an optical path of the light source modulation system in the present application is shown. The light source modulation system includes a first spatial light modulator 201, a light splitting element 202, a light homogenizing element 203, a second spatial light modulator 204, and a light combining element 205. The uniform light source light is incident on the first spatial modulator 201, and the first spatial modulator 201 modulates the light source light according to its modulation function, generating first image light and OFF light. The light splitting element 202 is disposed on the light emitting path of the first spatial light modulator, and is configured to separate the light path of the first image light from the light path of the OFF light, and guide the first image light to the light combining element 205 alone or in combination with other devices, and guide the OFF light to the light path where the second spatial light modulator 204 is located. The second spatial light modulator modulates the incident OFF light according to its modulation function to form second image light. The first image light and the second image light are output to the lens for projection imaging after being combined by the light combining element 205.

Preferably, the OFF light first passes through the light homogenizing element 203 to be homogenized when entering the second spatial light modulator 204.

Compared with the prior art, the scheme of directly discarding the OFF generated by the first spatial light modulator is adopted, the OFF generated by the first spatial light modulator is guided to the second spatial light modulator to be modulated to generate the second image light, and then the second image light is output after being combined with the first image light generated by the first spatial light modulator, so that the light energy utilization rate can be improved to a greater extent, and the image brightness can be improved.

Since the second spatial light modulator generates OFF light when modulating the second image light, those skilled in the art will easily recognize that a scheme of adding one more spatial light modulator to modulate and reuse the OFF light generated by the second spatial light modulator is added according to the inventive concept of the present application. The proposal does not exceed the inventive conception of the present application and belongs to the patent protection scope of the present application.

Referring to fig. 3, an optical path diagram of a light source modulation system according to an embodiment of the present application is shown. In this embodiment, the first spatial light modulator 301 is an LCD with an analyzer removed and the second spatial light modulator is a DMD. In this embodiment, the second spatial light modulator may be an LCD device or an LCOS device.

The light source modulation system includes an LCD301 with an analyzer removed, a polarizing beam splitter 302, a light homogenizing element 303, a DMD304, a polarizing beam splitter 305, and a reflecting sheet 306. After the light source light is incident on the LCD301 and modulated, the first image light 308 with P (or S) polarization state and the OFF light 309 with S (or P) polarization state are output, the OFF light 309 is homogenized by the homogenizing element 303 and then is incident on the DMD304, the DMD304 modulates the OFF light and then outputs the second image light 311, and since the DMD modulates the OFF light and does not change the polarization state, the second image light 311 has the S (or P) polarization state perpendicular to the polarization state of the first image light 308. The first image light 308 and the second image light 311 with mutually perpendicular polarization states are output after being combined by the polarization combining sheet 305.

In the present embodiment, light splitting and light combining may be performed by other methods than polarization light splitting.

Referring to fig. 4, an optical path diagram of a light source modulation system according to another embodiment of the present application is shown. The light source modulation system comprises an LCD401 with an analyzer removed, an LCD402, a polarization beam-splitting sheet PBS403, a reflecting sheet 4041/4042/4043, lenses 4051/4052 and fly's eye lenses 406. The uniform light source light 411 is incident on the LCD401 and modulated to generate a first image light 413 and an OFF light 412, the polarized light combining beam splitter 403 reflects the first image light 413 to transmit the OFF light 412, the OFF light 412 is collimated and converged by the lens 4051 and then reflected by the reflecting sheet 4043 to the fly eye lens 406, the fly eye lens 406 homogenizes the OFF light 412 and outputs the homogenized OFF light to the reflecting sheet 4042, the reflecting sheet 4042 outputs the homogenized OFF light to the lens 4052, the lens 4052 collimates and converges the OFF light and then reflects the collimated OFF light to the LCD402 via the reflecting sheet 4041, and the LCD402 modulates the OFF light. Since the LCD panel in the normal state can change the polarization state of the incident light, a half-wave plate can be added on the light path of the OFF light incident on the polarization beam splitter PBS403 to change the polarization state of the OFF light, so that the OFF light can pass through the polarization beam splitter PBS403, and the half-wave plate can be added on the incident light path of the LCD402 or on the emergent light path of the LCD 402. The second image light 414 is transmitted through the polarization beam combining beam splitter PBS403 and then combined with the first image light 413 to form a final image 415.

In this embodiment, the light splitting of the first image light and the OFF light and the light combining of the first image light and the second image light are multiplexed into the same PBS prism, so that the light source volume can be reduced.

It should be noted that, the LCD401 in the present embodiment may be replaced by a spatial light modulator that outputs polarized image light and OFF light, such as LCOS; the LCD402 may be replaced with any other form of spatial light modulator. Fly eye lens 406 may be replaced with other light homogenizing devices such as square bars.

Referring to fig. 5, an optical path diagram of a light source system according to an embodiment of the present application is shown. In the present figure, the colored arrow lines indicate the light of the corresponding light sources, and are not considered as limiting the light paths. In this embodiment, the input light source light is white light, that is, a polychromatic light source mixed with red, yellow and blue. The light source system includes a first color separation film 501, a second color separation film 502, a blue spatial light modulator 503, a green spatial light modulator 504, lenses 5051/5052, a reflective sheet 5061/5062/5063, a color separation cube 507, and a light modulation system 508.

The white light source is incident on the first light-splitting sheet 501, the first light-splitting sheet reflects blue light and transmits yellow light, the reflected blue light enters the blue light spatial light modulator 503, and the blue light is modulated and then output through the color-splitting cube device 507. The yellow light transmitted by the first dichroic sheet 501 includes red light and green light components, and the second dichroic sheet reflects green light and transmits red light, and the reflected green light is modulated by the green light spatial light modulator 504 and then output through the dichroic cube 507. The red light transmitted by the second beam splitter 502 is converged by the lens 5051, reflected by the reflecting sheets 5061 and 5062, converged by the lens 5052, reflected by the lens 5063, and then enters the light modulation system 508 to be modulated. The light modulation system 508 is a light modulator system in the embodiment of the present application, the first image light generated by modulating the incident red light by the first spatial light modulator 5081 is reflected by the PBS cube 5082 to the color separation cube device 507 and output, the OFF light generated by the first spatial light modulator 5081 is transmitted by the PBS cube 5082 and then enters the second spatial light modulator 5083 through a subsequent light path, the second spatial light modulator 5083 modulates the OFF light and outputs the second image light, and the second image light is transmitted by the PBS cube 5082 and then output through the color separation cube device 507.

The first spatial light modulator is an LCD with an analyzer removed, the second spatial light modulator is an LCD, and a half-wave plate is added to the path of OFF light incident on PBS cube 5082 to change its polarization state. It should be noted that the first spatial light modulator and/or the second spatial light modulator may be replaced by other types of modulators without the inventive effort to adapt the optical path.

In this embodiment, by adopting the light source modulation system in the present application for the red light path, the light energy utilization rate of red light can be improved, and the brightness of red light can be improved. The light source modulation system can also be adopted in the light paths of other colors.

Referring to fig. 6, a schematic light path diagram of a light source system according to another embodiment of the present application is shown. In the present figure, the colored arrow lines indicate the light of the corresponding light sources, and are not considered as limiting the light paths. In this embodiment, the input light source light is white light, that is, a polychromatic light source mixed with red, yellow and blue.

The light source system includes a first light splitter 601, a second light splitter 602, a first polarization beam splitter prism 603, a 1/2 wave plate 604, a first lens 611, a fly-eye lens 608, a second lens 612, a second polarization beam splitter prism 609, an LCD610 with an analyzer removed, a PBS cube 613, an LCD614, a blue spatial light modulator 605, a green spatial light modulator 606, and a dichroic cube 607.

The uniform light source light is incident on the first light-splitting sheet 601, the first light-splitting sheet 601 reflects blue light and transmits red light and green light, the reflected blue light enters the blue light spatial light modulator 605, and the modulated blue light is output through the color-splitting cube 607. The second dichroic plate 602 reflects green light and transmits red light, and the reflected green light is modulated by the green light spatial light modulator 606 and then output by the dichroic cube 607. Taking red light in P polarization state as an example, after the red light in P polarization state is transmitted through the second dichroic plate 602, the red light in P polarization state is incident on the first polarization splitting prism 603, the first polarization splitting prism 603 has the characteristic of transmitting P polarization light to reflect S polarization light, the red light in P polarization state is incident on the 1/2 wave plate 604,1/2 wave plate 604 after being transmitted through the first polarization splitting prism 603, the red light in P polarization state is converted into light in S polarization state, the light is collimated by the lens 611, the fly eye lens 608 is homogenized, the light is converged by the lens 612, the red light in P polarization state is incident on the second polarization splitting prism 609, the second polarization splitting prism 609 has the characteristic of reflecting S polarization light to transmit P polarization light, therefore, the incident red light in S polarization state is reflected to the LCD610, and the first image light in P polarization state and OFF light in S polarization state are generated after being modulated by the LCD610, and are both incident on the PBS cube 613 with transmitting P polarization light to reflect S polarization light. The first image light in P polarization state is transmitted through the PBS cube 613 and is output from the dichroic cube 607, the OFF light in S polarization state is reflected by the PBS cube 613 and is incident on the first polarization splitting prism 603, reflected by the first polarization splitting prism 603 and is incident on the 1/2 wave plate 604, converted into light in P polarization state, when the light is incident on the second polarization splitting prism 609, the light is transmitted through the second polarization splitting prism 609 and is incident on the LCD614, the second image light with S polarization is generated after being modulated by the LCD614, and the second image light is output with the first image light after being reflected by the dichroic cube 607.

Referring to fig. 7, a flowchart of a light source modulation method in an embodiment provided in the present application is shown. The light source modulation method comprises the following steps:

step S1: modulating light source light incident to the first spatial light modulator according to an image signal to generate first image light and OFF light;

step S2: modulating OFF light incident to the second spatial light modulator according to the image signal to generate second image light;

step S3: and combining the first image light and the second image light and outputting the combined light.

The first spatial light modulator and the second spatial light modulator modulate incident light according to image signals, so that the brightness proportion of each pixel in image light generated after the first image light and the second image light are combined can be ensured to be unchanged, and image display can not be distorted.

In step S2, if the loss of light energy by the device is not considered, all OFF light generated by the first spatial light modulator is incident on the second spatial light modulator as source light of the second spatial light modulator.

In one embodiment, the OFF light generated by the first spatial light modulator is homogenized and then enters the second spatial light modulator, and at this time, the brightness of the OFF light of each pixel entering the second spatial light modulator is the same; in another embodiment, a corresponding device is added between the first spatial light modulator and the second spatial light modulator to make the OFF brightness incident on each pixel of the second spatial light modulator different, for example, a device capable of implementing a local dimming function is added between the first spatial light modulator and the second spatial light modulator, so that the OFF light generated by the first spatial light modulator is arranged according to the brightness of the image signal when the OFF light is incident on the second spatial light modulator.

In addition, in the embodiment of the present application, light modulation is performed in units of pixels, the first spatial light modulator corresponds to the pixels of the first spatial light modulator one by one, and the light combining of the first image light generated by the first spatial light modulator and the second image light generated by the second spatial light modulator is actually the superposition of the brightness of the pixels of the first spatial light modulator and the brightness of the pixels corresponding to the second spatial light modulator.

Referring to fig. 8, a flowchart of a light source modulation method according to a second embodiment of the present application is shown.

Since the OFF light energy on the first spatial light modulator is utilized by the second spatial light modulator, there is substantially no optical energy loss without regard to device loss, but there is also an OFF light output on the second spatial light modulator, the inventive concept of this embodiment is: under the condition of ensuring that the image brightness proportion is unchanged, the brightness of the image light is provided by the second spatial light modulator as much as possible, so that the quantity of OFF light generated by the second spatial light modulator is reduced, the light energy utilization rate of a light source is utilized to the maximum extent, and the image brightness is improved.

In order to facilitate the description of the solution of this embodiment, the following description will take, as an example, the OFF light generated by the first spatial light modulator is homogenized and then is incident on the second spatial light modulator, but this is not a limitation of the present application:

step S1: modulating light source light incident to the first spatial light modulator according to an image signal to generate first image light and OFF light; the brightness of the first image light in the current pixel is L1, and the brightness of the OFF light is L2;

step S2: modulating OFF light incident to the second spatial light modulator according to the image signal to generate second image light; the brightness of the second image light in the current pixel is L3;

step S21: in the current pixel, obtaining the OFF luminance L21 incident to the second spatial light modulator;

when the OFF light generated by the first spatial light modulator is homogenized and then enters the second spatial light modulator, if the loss of light energy by the device is not considered, the OFF light brightness of the OFF light entering the second spatial light modulator=the sum of the OFF light brightness generated by all pixels of the first spatial light modulator ≡n of the pixels of the second spatial light modulator, l21= Σl2≡n.

Step S22: judging whether the sum of the first image brightness L1 and the second image brightness L3 is larger than the OFF brightness L21 incident to a second spatial light modulator;

step S23: if the sum of the first image brightness L1 and the second image brightness L3 is greater than or equal to the OFF brightness L21 of the current pixel incident on the second spatial light modulator, that is, l1+l3 is greater than or equal to L21, updating the second image brightness L3 generated by modulating the second spatial light modulator to the OFF brightness L21 of the current pixel incident on the second spatial light modulator, that is, l3=l21; and updating the first image brightness L1 generated by the modulation of the first spatial light modulator into a difference value between the sum of the first image brightness L1 and the second image brightness L3 and the OFF brightness L21 of the current pixel incident to the second spatial light modulator, namely L1=L1+L3-L21.

Step S24: if the sum of the first image brightness L1 and the second image brightness L3 is smaller than the OFF brightness L21 of the current pixel incident to the second spatial light modulator, that is, l1+l3 < L21, updating the second image brightness L3 generated by the modulation of the second spatial light modulator to be the sum of the first image brightness L1 and the second image brightness L3, that is, l3=l1+l3; the first image luminance L1 generated by the modulation of the first spatial light modulator is updated to zero.

S25: calculating the OFF light increment generated by the first spatial light modulator at the moment;

s26: calculating an OFF light increment incident to the second spatial light modulator according to the OFF light increment generated by the first spatial light modulator;

it should be noted that in this step, it is still necessary to calculate the OFF light increment generated by each pixel on the first spatial light modulator in the image frame, calculate the total OFF light increment generated by the first spatial light modulator, and then calculate the OFF light increment incident on each pixel of the second spatial light modulator;

step S27: modulating the OFF light increment incident to the second spatial light modulator according to the image signal to obtain increment brightness L22;

step S28: the second image light intensity L3 is updated to the sum of the second image light intensity L3 and the delta brightness L22, i.e., l3=l3+l22.

The present embodiment adjusts the contribution of the first spatial light modulator and the second spatial light modulator to the image brightness while maintaining the brightness of the image output by the first embodiment, calculates OFF light that the first spatial light modulator increases the output after the adjustment, obtains an OFF light increment input to the second spatial light modulator according to the OFF light that the first spatial light modulator increases the output, and remodulates the OFF light increment according to the image signal, thereby increasing the brightness of the second image light and further increasing the brightness of the output image light.

The above description describes a pixel light modulation process. Thus, unless otherwise specified, "brightness" refers to the brightness of the current pixel.

In the current pixel, if the first image light corresponding to the first spatial light modulator is zero, the pixel is in a full-closed state during the modulation period of the first spatial light modulator.

In addition, the luminance value on the right side of the equation in steps S23, S24, and S28 is the luminance value updated by the present method, and the luminance value on the left side of the equation is the luminance value before the update by the present method.

By adopting the method, the brightness value of each pixel in the first image light can be calculated, so that the first modulation function of the first spatial light modulator can be obtained, and the first spatial light modulator modulates the light source light according to the modulation function to generate the first image light. Similarly, the brightness value of each pixel on the second image light is also calculated, so that a second modulation function of the second spatial light modulator can be obtained, and the second spatial light modulator modulates the light incident on the second spatial light modulator according to the second modulation function. Here, the light incident on the second spatial light modulator may be light generated by homogenizing OFF light generated by the first spatial light modulator, or light generated by performing other processing (such as partial dimming) on OFF light generated by the first spatial light modulator.

Further, on the basis of the second embodiment, it may further include:

step S29: judging whether a preset condition is met or not; if yes, repeating steps S21-S28. If not, the light source light is directly modulated by a first modulation function obtained by calculating the brightness of each pixel of the current first spatial light modulator, and the light input to the second spatial light modulator is modulated by a second modulation function obtained by calculating the brightness of each pixel of the second spatial light modulator.

In one embodiment, the preset condition may be to determine whether the OFF light output by the second spatial light modulator is greater than a preset value. Of course, for different image signals, the OFF light output by the second spatial light modulator is not the same as in the case of maximizing the use of the light source. Therefore, the magnitude of the preset value can be obtained in advance by simple and limited repetition experiments, a table is established, and the preset value of the OFF light output by the different second spatial light modulator is set against the image signal.

In this embodiment, after the added OFF light is modulated, new image brightness is obtained, and by setting the condition for performing iterative processing, it is determined whether the iterative processing is required, so that the light energy utilization rate can be further improved.

In other embodiments, steps S21-S28 may be repeated once again after modulating the increased OFF light without determination.

The light source modulation system and the light source system in the present application may both adopt the light source modulation method in the present embodiment, so that for brevity of description, no further description is given.

Next, a light source modulation method in the present embodiment is exemplified:

since each pixel is generally modulated by an image frame in the image processing, the brightness of the pixel on the second spatial light modulator is related to not only the brightness of the image signal to be displayed but also the OFF light generated by all the pixels of the first spatial light modulator, and the following description of the modulation method in this embodiment is performed by taking 2 pixels A, B as an example:

referring to fig. 9a, let the brightness of the light source incident on the first spatial light modulator pixel A, B be 1, and the brightness of the image signal to be displayed by the pixel a and the pixel B be 0.1 and 0.7, respectively. That is, the luminance of the pixel A, B is 0.1 and 0.7 when one spatial light modulator is used.

The first spatial light modulator modulates the light source light incident on the pixel a according to the image signal, the brightness required to be displayed by the pixel a is 0.1, the corresponding first image brightness LA1 = 0.1 at the pixel a, the OFF brightness LA2 = 0.9 generated by the first spatial light modulator, the corresponding first image brightness LB1 = 0.7 at the pixel B, the OFF brightness LB2 = 0.3 generated by the first spatial light modulator, at this time, the total amount of OFF light generated by the first spatial light modulator is LA2+ LB2 = 1.2, and the OFF light generated by the first spatial light modulator is input to the second spatial light modulator after being subjected to dodging treatment, so the brightness input to the second spatial light modulator pixel A, B is LA21 = 1.2/2 = 0.6; that is, it is necessary to consider OFF light generated by each pixel in calculating the total amount of OFF light generated by the first spatial light modulator, and then calculate the total OFF light input to the second spatial light modulator, and calculate the OFF light luminance of each pixel input to the second spatial light modulator according to the resolution of the second spatial light modulator, that is, the number of pixels to be displayed.

In order to ensure that the image display color is not distorted, the second spatial light modulator also needs to modulate OFF light input to a pixel a of the second spatial light modulator according to an image signal to generate second image light, wherein the display brightness la3=0.1×0.6=0.06 at the pixel a and the brightness lb3=0.7×0.6=0.42 at the pixel B; at this time, the liquid crystal display device,

for the pixel a, the luminance thereof becomes la1+la3=0.1+0.06=0.16; for the pixel B, the luminance thereof becomes lb1+lb3=0.7+0.42=1.12.

Therefore, the use of a dual spatial light modulator to modulate the light source can increase the brightness of the output image light relative to a single spatial light modulator.

Further, please refer to fig. 9b.

The luminance of the pixel a is 0.16 less than the OFF luminance la21=0.6 input to the second spatial light modulator pixel a, and the luminance of the first image light at the pixel a la1=0 and the luminance of the second image light at the pixel a la3=la1+la3=0.16.

The luminance of the pixel B is lb1+lb3=0.7+0.42=1.12 greater than the OFF luminance lb21=0.6 input to the second spatial light modulator pixel B, and the luminance lb1=lb1+lb3-lb21=0.7+0.42-0.6=0.52 of the first image light at the pixel B and the luminance lb3=lb21=0.6 of the second image light at the pixel B input to the second spatial light modulator pixel B.

At this time, for pixel a: the first image brightness is LA1 = 0, and the second image brightness is LA3 = 0.16; for pixel B: first image light brightness lb1=0.52, second image light brightness lb3=0.6. The total brightness of the output image light is still pixel a:0.16, pixel B:1.12.

further processing is performed, at this time, for the first spatial light modulator, the total amount of OFF light output before adjustment is 1-0.1+1-0.7=1.2, and the total amount of OFF light output after adjustment is 1-0+1-0.52=1.48. Therefore, the total OFF light increment generated by the first spatial light modulator is 1.48-1.2=0.28, and after light homogenization, the OFF light increment respectively entering the pixels A and B of the second spatial light modulator is 0.28/2=0.14.

The OFF light increment is modulated according to the image signal, and since the luminance displayed at the pixel a is 0.1 and the luminance displayed at the pixel B is 0.7, the luminance increment of the pixel a is la22=0.1×0.14=0.014 and the luminance increment of the pixel B is lb22=0.7×0.14=0.098 in order to ensure that the image display is not distorted.

After updating, the brightness of the second image generated by the second spatial light modulator modulation for the pixel a is LA3 = LA3+ LA22 = 0.16+0.014 = 0.174; the second image luminance generated by the second spatial light modulator modulation for the pixel B is lb3=lb3+lb22=0.6+0.0988= 0.6988.

At this time, the output image is bright, pixel a: 0+0.174=0.174, pixel B: 0.52+0.698=1.218. The method further increases the brightness of the output image light relative to the method in fig. 9 a.

In the above manner, each pixel in the image frame is processed separately.

And updating the second modulation function according to the updated brightness of the second image light pixel, and modulating the OFF light entering the second spatial light modulator according to the updated second modulation function by the second spatial light modulator.

Further, since the luminance of the pixel A, B is changed after the above operation, the relationship between the luminance of the pixel A, B and the OFF luminance inputted to the second spatial light modulator pixel A, B can be determined again, and the above process is repeated when the preset condition is satisfied.

Referring to fig. 10, an effect diagram of the light modulation method on image brightness enhancement in the present application is shown. Wherein curve 1 is the luminance (i.e., image light output after using a single spatial light modulator) distribution curve of the original image, curve 2 is the luminance distribution curve of the image light after modulating the light source by using the dual spatial light modulation system of the present application and the light source modulation method of the first embodiment, and curve 3 is the luminance distribution curve after modulating the image by using the light source modulation method of the second embodiment of the present application. It can be seen from the figure that the light source modulation system and the light source modulation method in the first embodiment of the present application can improve the image brightness, and the light source modulation method in the second embodiment of the present application can further improve the image brightness based on the first embodiment.

It should be noted that, the light modulation methods in the present application are all described without considering the condition of the device for light energy loss, and in practical application, the adaptive modification of the light modulation methods in the present application by considering the loss of the light energy by the related device is a scheme that is easily thought by those skilled in the art, and the inventive labor is not required, and the method still belongs to the patent protection scope of the present application.

The foregoing description is only exemplary embodiments of the present application and is not intended to limit the scope of the present application, and all equivalent structures or equivalent processes using the descriptions and the drawings of the present application, or direct or indirect application in other related technical fields are included in the scope of the present application.

Claims

1. A light source modulation system is characterized by comprising a first spatial light modulator, a light splitting element, a second spatial light modulator and a light combining element;

the first spatial light modulator is used for modulating incident light source light to form first image light and generating OFF light;

the light splitting element is configured to separate the first image light from the optical path of the OFF light, guide the first image light to the light combining element, and guide the OFF light to the second spatial light modulator;

the second spatial light modulator modulates the OFF light to form second image light;

the light combining element combines the first image light and the second image light;

the system further comprises a modulation function input module, wherein the modulation function input module is used for adjusting the modulation functions of the first spatial light modulator and the second spatial light modulator so as to minimize OFF light generated by the second spatial light modulator.

2. The light source modulation system according to claim 1, further comprising a light uniformizing element provided on an optical path between the light splitting element and the second spatial light modulator for uniformizing OFF light generated by the first spatial light modulator.

3. The light source modulation system of claim 1, wherein the first spatial light modulator is an LCD panel with an analyzer removed; the second spatial light modulator is one of DMD, LCD, LCOS.

4. A light source modulation system according to claim 3, wherein the light splitting element multiplexes the same PBS prism as the light combining element.

5. A light source modulation method applied to the light source modulation system according to any one of claims 1 to 4, comprising:

6. The light source modulation method according to claim 5, further comprising, after step S2:

step S21: obtaining the OFF luminance of light incident on the second spatial light modulator in the current pixel;

step S22: judging whether the sum of the brightness of the first image and the brightness of the second image is larger than the OFF brightness incident on a second spatial light modulator;

step S23: if the sum of the first image brightness and the second image brightness is greater than or equal to the OFF brightness incident on the second spatial light modulator, updating the second image brightness to the OFF brightness incident on the second spatial light modulator, and updating the first image brightness to the difference between the sum of the first image brightness and the second image brightness and the OFF brightness incident on the second spatial light modulator;

step S24: if the sum of the first image brightness and the second image brightness is smaller than the OFF brightness incident to the second spatial light modulator, updating the second image brightness to the sum of the first image brightness and the second image brightness, and updating the first image brightness to zero;

step S25: calculating an OFF light increment generated by the first spatial light modulator at the moment;

step S26: calculating the OFF light increment incident to the second spatial light modulator according to the OFF light increment generated by the first spatial light modulator;

step S27: modulating the OFF light increment incident to the second spatial light modulator according to an image signal to obtain incremental brightness;

step S28: and updating the brightness of the second image to be the sum of the brightness of the second image and the increment brightness.

7. The light source modulation method according to claim 6, further comprising, after said step S28:

step S29: judging whether a preset condition is met or not;

if yes, repeating steps S21-S28.

8. The light source modulation method according to claim 7, wherein the preset condition includes: and the OFF light output by the second spatial light modulator is larger than a preset value.

9. The light source modulation method according to claim 6, further comprising, after said step S28: steps S21-S28 are repeated once.

10. A light source modulation method according to any one of claims 5 to 9 wherein OFF light emitted from the first spatial light modulator is homogenized and then incident on the second spatial light modulator.

11. A light source modulation method according to any one of claims 5 to 9, wherein OFF light emitted from the first spatial light modulator is locally dimmed before being incident on the second spatial light modulator.

12. A light source modulation method according to any one of claims 5-9, wherein each pixel in an image frame is processed according to the method: calculating a first modulation function of a first spatial light modulator according to the first image brightness, and calculating a second modulation function of a second spatial light modulator according to the second image brightness; the first spatial light modulator modulates light source light according to the first modulation function, and the second spatial light modulator modulates light incident to the second spatial light modulator according to the second modulation function.

13. A light source system comprising a polychromatic light source, wherein at least one of the polychromatic light sources is light source modulated by a light source modulation system according to any one of claims 1-4, a light source modulation method according to any one of claims 1-12.

14. The light source system of claim 13, wherein the polychromatic light source is a red, green and blue light source.