A method, apparatus and projection device for local dimming and thermal load balancing

Abstract

Embodiments of the present application disclose a local dimming heat load balancing method, device and projection equipment. The method comprises the following steps: obtaining a first display image displayed by a first spatial light modulator based on a preset image when the projection equipment is locally dimmed; obtaining a first heat load of the first spatial light modulator according to the first display image; adjusting output power of the first spatial light modulator if the first heat load is higher than a first heat resistance capacity of the first spatial light modulator; obtaining a first target image for displaying on the first spatial light modulator according to the adjusted output power of the first spatial light modulator; and obtaining a second target image for displaying on a second spatial light modulator according to the preset image and the first target image. By using the above method, the heat load on the spatial light modulator when the projection equipment is locally dimmed can be effectively balanced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of projection display, and more particularly to a local dimming heat load balancing method and device and projection equipment. BACKGROUND

[0002] At present, high dynamic contrast is one of the main pursuits of a new generation of display equipment. For a projection display device, a scheme for improving the dynamic contrast of the device is to modulate through two or more spatial light modulators in series to reduce the dark field brightness and improve the dynamic contrast of the device. However, since the spatial light modulator is usually smaller than the projected picture, there is a problem that the heat effect of the device is obvious due to the large light flux of the spatial light modulator, thereby restricting the projection performance of the projection device. SUMMARY

[0003] The present application provides a local dimming heat load balancing method, device and projection equipment to improve the above problem.

[0004] In a first aspect, an embodiment of the present application provides a local dimming heat load balancing method applied to a projection device including a first spatial light modulator and a second spatial light modulator. The method includes: obtaining a first display image displayed by the first spatial light modulator based on a preset image when the projection device is locally dimmed; obtaining a first heat load of the first spatial light modulator according to the first display image; adjusting an output power of the first spatial light modulator if the first heat load is higher than a first heat resistance of the first spatial light modulator; obtaining a first target image for displaying on the first spatial light modulator after the output power is adjusted according to the adjusted output power of the first spatial light modulator; and obtaining a second target image for displaying on the second spatial light modulator according to the preset image and the first target image.

[0005] In a second aspect, the embodiments of the present application further provide a device for local dimming and thermal load balancing. The device comprises an initial image acquisition module, a thermal load acquisition module, a thermal load balancing module, a first target image acquisition module, and a second target image acquisition module. The initial image acquisition module is configured to acquire a first display image displayed by the first spatial light modulator based on a preset image when the projection device is locally dimmed. The thermal load acquisition module is configured to obtain a first thermal load of the first spatial light modulator according to the first display image. The thermal load balancing module is configured to adjust an output power of the first spatial light modulator if the first thermal load is higher than a first heat resistance of the first spatial light modulator. The first target image acquisition module is configured to obtain a first target image for displaying on the first spatial light modulator after the output power is adjusted according to the adjusted output power of the first spatial light modulator. The second target image acquisition module is configured to obtain a second target image for displaying on the second spatial light modulator according to the preset image and the first target image.

[0006] In a third aspect, the embodiments of the present application further provide a projection device. The projection device comprises a first spatial light modulator, a second spatial light modulator, a display, one or more processors, a memory, and one or more application programs. The first spatial light modulator and the second spatial light modulator are connected in series and configured to locally dim. The display is configured to display a preset image. The one or more application programs are stored in the memory and configured to be executed by the one or more processors. The one or more programs are configured to be executed to implement the method of the first aspect.

[0007] In a fourth aspect, the embodiments of the present application further provide a computer readable storage medium. The computer readable storage medium stores program codes. The program codes can be invoked by a processor to execute the method of the first aspect.

[0008] The technical scheme provided by the application is applied to a projection device comprising a first spatial light modulator and a second spatial light modulator, and the first display image displayed by the first spatial light modulator based on a preset image is obtained when local dimming of the projection device is acquired; the first thermal load of the first spatial light modulator is obtained according to the first display image; if the first thermal load is higher than the first heat resistance of the first spatial light modulator, the output power of the first spatial light modulator is adjusted; the first target image for display on the first spatial light modulator after adjustment of the output power is obtained according to the adjusted output power of the first spatial light modulator; and the second target image for display on the second spatial light modulator is obtained according to the preset image and the first target image. Therefore, by using the above method of the application, the output power of the first spatial light modulator for local dimming of the projection device is improved, the thermal load on the spatial light modulator during local dimming of the projection device is effectively balanced, and the high dynamic contrast of the projection device is achieved while avoiding the projection performance of the projection device being obviously restricted by the thermal effect of the spatial light modulator. BRIEF DESCRIPTION OF DRAWINGS

[0009] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative effort.

[0010] Figure 1 A flowchart of a local dimming thermal load balancing method according to an embodiment of the present application is shown;

[0011] Figure 2 A flowchart of obtaining the preset output power value and the preset light source reduction ratio value of a local dimming thermal load balancing method according to an embodiment of the present application is shown;

[0012] Figure 3 A structural diagram of a local dimming thermal load balancing device according to an embodiment of the present application is shown;

[0013] Figure 4 A structural block diagram of a projection device according to an embodiment of the present application is shown;

[0014] Figure 5 A structural block diagram of a computer readable storage medium according to an embodiment of the present application is shown. DETAILED DESCRIPTION

[0015] In the following, the technical solutions in the embodiments of the present application will be described clearly and completely in conjunction with the drawings in the embodiments of the present application, so that those skilled in the art can better understand the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application.

[0016] At present, high dynamic range (HDR) is one of the main pursuits of the new generation of display devices, and one of the connotations of high dynamic range is that the dark field of the display device needs to be low enough, and the display bit depth needs to be high enough. In the prior art, the control algorithm of local dimming has many goals, such as trying to lower the brightness of local illumination light to reduce the dark field. Therefore, the way of reducing the dark field brightness to achieve high dynamic range through local dimming is very common. For projection display, the scheme of reducing the dark field brightness and improving the dynamic range of the device can be to modulate through two or more spatial light modulators (SLMs) in series. After the illumination light passes through the first SLM, it becomes a local dimming illumination light, which can effectively reduce the illumination light of the dark field. Under the premise that the modulation capability of the second SLM does not change, the decrease of the illumination light brightness can improve the brightness of the dark field, and the use of double spatial light modulators can also effectively improve the equivalent bit depth of the display device. In the field of display and television, local dimming is realized by multiple LED beads, and since the light flux density is not high and the heat effect is not obvious. However, for projection display, since the SLM is usually smaller than the projection picture, the light flux of the SLM is very large, especially the first SLM, which usually bears a lot of heat. For example, the non-image light of 3LCD and LCOS is almost all absorbed by the panel or polarizing plate; although DMD can emit most of the energy of non-image light, there is still a phenomenon that the dark field temperature load is not negligible. The heat dissipation capacity of the device is usually a key factor affecting the performance of the device system. In the projection device using local dimming of spatial light modulator, if the heat on the spatial light modulator is difficult to dissipate, the spatial light modulator may be damaged by overheating, thereby affecting the performance of the whole projection device. Therefore, when using spatial light modulator for local dimming of projection device, there is a problem that the projection performance of the projection device is restricted due to the obvious heat effect of the spatial light modulator.

[0017] Therefore, in order to alleviate the above problems, the embodiment of the present application provides a local dimming heat load balancing method. By using the above method of the present application, on the basis of realizing high dynamic contrast of the projection device, the first display image displayed by the first spatial light modulator based on the preset image is obtained when the local dimming of the projection device is realized. The first heat load of the first spatial light modulator is obtained according to the first display image. If the first heat load is higher than the first heat resistance of the first spatial light modulator, the output power of the first spatial light modulator is adjusted. The first target image for displaying on the first spatial light modulator after adjusting the output power is obtained according to the adjusted output power of the first spatial light modulator. The second target image for displaying on the second spatial light modulator is obtained according to the preset image and the first target image, so as to effectively balance the heat load of the spatial light modulator for local dimming of the projection device, enhance the quality of the projection device display picture, and improve the projection performance of the projection device.

[0018] The embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0019] Please refer to Figure 1 The embodiment of the present application provides a local dimming heat load balancing method, which is applied to a projection device including a first spatial light modulator and a second spatial light modulator. The method can include steps S110 to S150.

[0020] Step S110: obtaining a first display image displayed by the first spatial light modulator based on a preset image when the local dimming of the projection device is realized.

[0021] In the embodiment of the present application, the projection device can include a first spatial light modulator, a second spatial light modulator, a light source and a display screen. The local dimming of the projection device can be that when the illumination light emitted by the light source is incident on the first spatial light modulator, the first spatial light modulator modulates the illumination light into a special distribution of local illumination illumination light, which can effectively reduce the illumination light brightness of the dark field. At the same time, the first spatial light modulator transfers the local illumination illumination light to the second spatial light modulator, and the second spatial light modulator modulates the illumination light modulated once by the first spatial light modulator again. After two times of modulation, the brightness of the illumination light is reduced, the brightness of the dark field of the projection device is improved, and the dynamic contrast of the projection device is improved.

[0022] Specifically, the spatial light modulator can be a transmissive spatial light modulator, a reflective spatial light modulator, a liquid crystal spatial light modulator, or the like. The first spatial light modulator and the second spatial light modulator can be of the same type or different types. For example, the first spatial light modulator is an LCD panel, and the second spatial light modulator is an RGB LCD panel or an RGBW LCD panel. The first spatial light modulator and the second spatial light modulator can both be DMDs. The LCD, LCOS (reflective liquid crystal display), absorbs most of the heat of certain specific polarizations, so the heat load is completely superimposed on the LCD or LCOS. The DMD digital micromirror reflects the unwanted light out of the DMD, and although it does not absorb non-image light, the heat absorption is also improved. Therefore, when using 3LCD, LCOS, and DMD to locally dim the projection device, the heat effect is obvious, which restricts the projection performance of the projection device.

[0023] The preset image is an image expected to be displayed on the screen of the projection device. The preset image can be obtained from an associated electronic device or a cloud through wireless communication technology, or obtained from an associated device through SPI (serial communication interface). The local dimming is completed under the condition that the screen of the projection device displays the preset image. That is, when the projection device is locally dimmed and the heat load of the spatial light modulator balancing the local dimming of the projection device is balanced, the image displayed on the screen of the projection device is the preset image.

[0024] When the projection device is locally dimmed, the screen of the projection device displays the preset image, the first spatial light modulator displays a first display image based on the preset image, and the second spatial light modulator displays a second display image based on the preset image. The first display image and the second display image are the initial solution when the local dimming is performed. The first display image can be obtained by capturing the image displayed on the first spatial light modulator through a camera, and the second display image can be obtained by capturing the image displayed on the second spatial light modulator through a camera.

[0025] In step S120, the first heat load of the first spatial light modulator is obtained based on the first display image.

[0026] In the embodiment of the present application, after the first display image based on the preset image display by the first spatial light modulator when the projection device locally adjusts the light, the first exit power of the first spatial light modulator can be obtained according to the image reflected by the first spatial light modulator, that is, the brightness and color of the first display image are converted into energy, so as to obtain the first exit power of the first spatial light modulator.

[0027] In the embodiment of the present application, the first heat load of the first spatial light modulator can be obtained according to the first display image, which can be obtained according to an absorption power calculation formula of the spatial light modulator, wherein the absorption power calculation formula is:

[0028] H = (1-η)W in +a(ηW in -W out ),

[0029] wherein H represents the absorption power of the spatial light modulator; W in represents the incident power of the illumination light; W out represents the exit power of the spatial light modulator; η represents the transmittance of the spatial light modulator; and a represents the absorption rate of the spatial light modulator. Specifically, η represents the ratio of the exit power of the white field of the spatial light modulator to the incident power of the illumination light when the incident power of the illumination light is a certain value; a represents the absorption rate of the spatial light modulator, that is, the ratio of the increment of the energy absorbed when the spatial light modulator displays black to the increment of the energy absorbed when the spatial light modulator displays white to the increment of the output energy of the white field of the spatial light modulator to the output energy of the black field of the spatial light modulator. (1-η)W in represents the energy that is not transmitted through the spatial light modulator; a(ηW in -W out represents the energy that is incident on the spatial light modulator but does not exit.

[0030] The incident power of the illumination light emitted by the light source of the projection device, the first exit power of the first spatial light modulator, the first absorption rate and the first transmittance are calculated by using the absorption power calculation formula, so as to obtain the first heat load of the first spatial light modulator, wherein the absorption power calculation formula is:

[0031] H1 = (1-η1)W in +a1(η1W in -W out,1 ),

[0032] wherein H1 represents the first heat load of the first spatial light modulator; η1 represents the first transmittance of the first spatial light modulator; a1 represents the first absorption rate of the first spatial light modulator; W out,1a first exit power of the first spatial light modulator.

[0033] In some embodiments, if the first spatial light modulator and the second spatial light modulator are of different types, and the second heat resistance of the second spatial light modulator is less than the first heat resistance of the first spatial light modulator, when the local dimming of the projection device is acquired, the first spatial light modulator displays a first display image based on a preset image, and the second spatial light modulator displays a second display image based on a preset image; the first heat load of the first spatial light modulator is obtained according to the first display image, and the second heat load of the second spatial light modulator is obtained according to the second display image; if the second heat load is higher than the second heat resistance of the second spatial light modulator, the brightness of the light source incident on the first spatial light modulator can be adjusted.

[0034] The second heat load can be obtained by using an absorption power calculation formula to calculate the incident power of the illumination light emitted by the light source of the projection device, the second exit power of the second spatial light modulator, the second absorption rate, and the second transmittance, to obtain the second heat load of the second spatial light modulator, where the absorption power calculation formula is:

[0035] H2=(1-η2)W out,1 +a2(η2W out,1 -W out,2 ),

[0036] where H2 is the second heat load of the second spatial light modulator, η2 is the second transmittance of the second spatial light modulator, a2 is the second absorption rate of the second spatial light modulator, w2 is the second heat resistance of the second spatial light modulator, W0 is the maximum output power of the light source, and W is the second exit power of the second spatial light modulator. out,2

[0037] In the embodiments of the present application, the second heat resistance of the second spatial light modulator is the maximum power that can be absorbed by the spatial light modulator, and if the second heat load is higher than the second heat resistance of the second spatial light modulator, the heat load on the second spatial light modulator needs to be adjusted to prevent the second spatial light modulator from being burned out due to excessive heat load. Specifically, the brightness of the light source incident on the first spatial light modulator can be adjusted, so that the heat loads of the first spatial light modulator and the second spatial light modulator are both reduced, and the components of the projection device can be prevented from being burned out.

[0038] Step S130: If the first heat load is higher than the first heat resistance of the first spatial light modulator, the output power of the first spatial light modulator is adjusted.

[0039] ​In the embodiment of the present application, the first heat tolerance of the first spatial light modulator is the maximum power that the spatial light modulator can absorb. If the first heat load is higher than the first heat tolerance of the first spatial light modulator, i.e. H1> w1, where H1= (1- η1) W in + a1(η1W in -W out,1 ), w1 represents the first heat tolerance of the first spatial light modulator. In order to prevent the first spatial light modulator from being burned out due to the excessive heat load, the heat load on the first spatial light modulator needs to be adjusted. The adjustment of the heat load on the first spatial light modulator can be adjusting the brightness of the light source incident on the first spatial light modulator, or increasing the output power of the first spatial light modulator.

[0040] Specifically, if the brightness of the light source incident on the first spatial light modulator is adjusted, the energy of the entire projection device will be reduced. If the output power of the first spatial light modulator is increased, i.e. the first spatial light modulator does not block too much light, it displays more white and less black, and the light is transferred to the second spatial light modulator. In this way, the heat load on the first spatial light modulator can be transferred to the second spatial light modulator, the heat load of the spatial light modulator in the local dimming of the projection device is balanced, and the brightness of the projection device is increased.

[0041] For example, the embodiment of the present application is applied to spatial light modulators with high absorption rate, 3LCD and LCOS. The non-image light of 3LCD and LCOS is almost entirely absorbed by the panel or polarizing plate, so the absorption rate is high. 3LCD is a system that divides the input white light into red, green and blue light. A panel is placed before the light is divided to modulate the white light. In this way, the red, green and blue light after the light is divided will receive the modulation. By taking the panel placed before the light is divided as the first spatial light modulator, and the panel with the highest heat load on the RGB panel (red panel, green panel, blue panel) as the second spatial light modulator, the first heat load on the first spatial light modulator is obtained, and it is determined whether the first heat load is higher than the first heat tolerance of the spatial light modulator. If it is higher, the output power of the first spatial light modulator or the brightness of the light source incident on the first spatial light modulator can be reduced to balance the heat load of the local dimming system of the 3LCD.

[0042] In some embodiments, if the first heat load is higher than the first heat tolerance of the first spatial light modulator, the heat load balance of the projection device when locally adjusting light can be achieved by increasing the output power of the first spatial light modulator, or by reducing the brightness of the light source incident on the first spatial light modulator, or by increasing the output power of the first spatial light modulator and adjusting the brightness of the light source incident on the first spatial light modulator. The output power of the first spatial light modulator is not unlimited, because the first spatial light modulator itself absorbs heat, and a portion of the heat is absorbed by the first spatial light modulator regardless of the image displayed by the first spatial light modulator. Therefore, the reduction of the heat load of the first spatial light modulator by changing the image displayed by the first spatial light modulator is limited. If the first heat load of the first spatial light modulator is much higher than the first heat tolerance of the first spatial light modulator, the first heat load of the first spatial light modulator needs to be reduced by reducing the brightness of the light source incident on the first spatial light modulator. However, the brightness of the light source incident on the first spatial light modulator should also be limited, which should ensure the projection capability of the projection device, i.e., ensure that the preset image is displayed on the screen of the projection device.

[0043] Specifically, the adjustment of the output power of the first spatial light modulator can be to adjust the color or brightness of the first display image displayed by the first spatial light modulator based on the preset image according to a preset output power value, so as to adjust the output power of the first spatial light modulator, and further transfer a portion of the first heat load of the first spatial light modulator to the second spatial light modulator, so as to balance the heat load on the spatial light modulators when the projection device locally adjusts light. The adjustment of the brightness of the light source incident on the first spatial light modulator can be to adjust the brightness of the light source incident on the first spatial light modulator by reducing the voltage or current of the projection device according to a preset light source reduction ratio value.

[0044] Please refer to Figure 2 In the embodiments of the present application, the preset output power value and the preset light source reduction ratio value can be obtained through the processes of steps S132 to S136.

[0045] Step S132: Obtain the first display image displayed by the first spatial light modulator based on the preset image and the second display image displayed by the second spatial light modulator based on the preset image when the projection device locally adjusts light.

[0046] Specifically, the way of obtaining the first display image displayed by the first spatial light modulator based on the preset image and the second display image displayed by the second spatial light modulator based on the preset image when the projection device locally adjusts light can be to use a camera to capture.

[0047] Step S134: determining the first exit power of the first spatial light modulator and the second exit power of the second spatial light modulator according to the first display image and the second display image.

[0048] Specifically, the first exit power of the first spatial light modulator and the second exit power of the second spatial light modulator can be determined according to the first display image and the second display image by converting the brightness and color of the first display image into energy to obtain the first exit power of the first spatial light modulator, and converting the brightness and color of the second display image into energy to obtain the second exit power of the second spatial light modulator.

[0049] Step S136: obtaining the preset output power value and the preset light source reduction ratio value according to the first transmittance, the first absorptance, the first heat resistance and the first exit power of the first spatial light modulator, the second transmittance, the second absorptance, the second heat resistance and the second exit power of the second spatial light modulator, and the maximum output power of the light source.

[0050] Specifically, the first transmittance, the first absorptance, the first heat resistance and the first exit power of the first spatial light modulator and the maximum output power of the light source are brought into the first spatial light modulator's absorption power calculation formula to obtain a first inequality; the second transmittance, the second absorptance, the second heat resistance and the second exit power of the second spatial light modulator and the maximum output power of the light source are brought into the second spatial light modulator's absorption power calculation formula to obtain a second inequality; the first inequality, the second inequality, a third inequality that the preset light source reduction ratio value is greater than 0 and less than or equal to 1, and a fourth inequality that the preset output power value is greater than 0 and less than or equal to the energy not exited by the first spatial light modulator form a target inequality group, and the value range of the preset output power value and the value range of the preset light source reduction ratio value are obtained by solving the target inequality group. The target inequality group includes:

[0051]

[0052] wherein η1 is the first transmittance of the first spatial light modulator, η2 is the second transmittance of the second spatial light modulator, a1 is the first absorptance of the first spatial light modulator, a2 is the second absorptance of the second spatial light modulator, w1 is the first heat resistance of the first spatial light modulator, w2 is the second heat resistance of the second spatial light modulator, W0 is the maximum output power of the light source, W out,1 is the first exit power of the first spatial light modulator, W out,2is a second exit power of the second spatial light modulator, k is the preset light source reduction ratio value, and AW is the preset output power value.

[0053] Specifically, the first inequality indicates that the first thermal load of the first spatial light modulator is less than or equal to the first heat resistance capability of the first spatial light modulator; the second inequality indicates that the second thermal load of the second spatial light modulator is less than or equal to the heat resistance capability of the second spatial light modulator; the third inequality indicates that the preset light source reduction ratio value is greater than 0 and less than or equal to 1; and the fourth inequality indicates that the preset output power value is greater than 0 and less than or equal to the energy not exited by the first spatial light modulator. Solving the inequality group composed of the first inequality, the second inequality, the third inequality, and the fourth inequality obtains the value range of the preset light source reduction ratio value k and the value range of the preset output power value AW, and according to the value range of the preset output power value, the largest preset output power value AW is taken, the output power of the first spatial light modulator is increased by AW based on the first exit power W out,1 of the first spatial light modulator, or according to the value range of the preset output power value, the largest preset output power value AW is taken, the output power of the first spatial light modulator is increased by AW based on the first exit power of the first spatial light modulator, and according to the value range of the preset light source reduction ratio value, the smallest preset light source reduction ratio value k is taken, the brightness of the light source is reduced to kW0 based on the maximum output power W0 of the light source. out,1 of the first spatial light modulator, or according to the value range of the preset output power value, the largest preset output power value AW is taken, the output power of the first spatial light modulator is increased by AW based on the first exit power of the first spatial light modulator, and according to the value range of the preset light source reduction ratio value, the smallest preset light source reduction ratio value k is taken, the brightness of the light source is reduced to kW0 based on the maximum output power W0 of the light source.

[0054] The preset output power value and the preset light source reduction ratio value can be obtained according to the process of steps S132 to S136, pre-stored in the storage unit of the projection device, or obtained from the associated cloud or electronic device through wireless communication technology, or obtained from the associated electronic device through SPI (serial communication interface).

[0055] Step S140: obtaining a first target image for display on the first spatial light modulator according to the adjusted output power of the first spatial light modulator.

[0056] In the embodiments of the present application, the first target image for display on the first spatial light modulator after adjusting the output power of the first spatial light modulator is obtained according to the adjusted output power of the first spatial light modulator. Specifically, the output power of the first spatial light modulator can be increased by AW, and the adjusted output power value of the first spatial light modulator, the first exit power, the first absorption rate, the first display image, and the maximum output power of the light source are brought into a first target calculation formula to obtain the first target image for display on the first spatial light modulator after adjusting the output power, wherein the first target calculation formula includes:

[0057]

[0058] wherein I1 is the first display image displayed by the first spatial light modulator based on the preset image; I1' is the first target image for display on the first spatial light modulator after adjusting the output power; AW is the adjusted output power value of the first spatial light modulator; W out,1 is the first exit power of the first spatial light modulator; η1 is the first absorption rate of the first spatial light modulator; W0 is the maximum input power of the light source.

[0059] Step S150: obtaining a second target image for display on the second spatial light modulator according to the preset image and the first target image.

[0060] In the embodiments of the present application, the second target image for display on the second spatial light modulator can be obtained according to the first display image and the second display image before obtaining the first heat load of the first spatial light modulator according to the first display image, when the local dimming of the projection device is acquired, the first display image displayed by the first spatial light modulator based on the preset image and the second display image displayed by the second spatial light modulator based on the preset image; according to the first display image and the second display image, a transfer relationship from the first display image to the second display image is obtained; and according to the transfer relationship, the first target image, and the preset image, the second target image for display on the second spatial light modulator is obtained.

[0061] Specifically, the transfer relationship can be obtained according to a first pixel in the first display image and a second pixel in the second display image, and the transfer relationship formula of the first pixel and the second pixel is:

[0062] I 21 = T(I1),

[0063] wherein I1 is the first display image, I 21 is the distribution image of the output light of the first spatial light modulator on the second spatial light modulator.

[0064] The second target image for display on the second spatial light modulator can be obtained by calculating the first target image using the transfer relationship formula, to obtain a distribution image of the output light of the first spatial light modulator on the second spatial light modulator after adjusting the output power of the first spatial light modulator, and the transfer relationship formula is:

[0065] I 21 '=T(I1'),

[0066] wherein, I 21 ' is the distribution image of the output light of the first spatial light modulator on the second spatial light modulator after adjusting the output power of the first spatial light modulator, and I1' is the first target image.

[0067] The second target image for display on the second spatial light modulator can be obtained by calculating the first target image using the transfer relationship formula, to obtain a distribution image of the output light of the first spatial light modulator on the second spatial light modulator after adjusting the output power of the first spatial light modulator, and the transfer relationship formula is:

[0068] I2'=I0 / I 21 ',

[0069] wherein, I 21 ' is the distribution image of the output light of the first spatial light modulator on the second spatial light modulator after adjusting the output power of the first spatial light modulator, and I2' is the second target image, and I0 is the preset image.

[0070] The technical scheme of the present application, when using a double-piece spatial light modulator to realize high dynamic contrast of a projection device, a first display image displayed by the first spatial light modulator based on a preset image is obtained when the projection device is locally dimmed; a first heat load of the first spatial light modulator is obtained according to the first display image; if the first heat load is higher than a first heat resistance of the first spatial light modulator, the output power of the first spatial light modulator is adjusted; a first target image for display on the first spatial light modulator after adjusting the output power is obtained according to the adjusted output power of the first spatial light modulator; and a second target image for display on the second spatial light modulator is obtained according to the preset image and the first target image. Therefore, by using the above-mentioned method of the present application, the heat load of the projection device is balanced when the projection device is locally dimmed, so as to enhance the picture quality of the projection device, avoid the heat effect from significantly restricting the system performance of the projection device, and further improve the projection capability of the projection device.

[0071] Please refer toFigure 3 Another embodiment of the present application provides a device for local dimming and thermal load balancing, the device 300 comprising: an initial image acquisition module 310, a thermal load acquisition module 320, a thermal load balancing module 330, a first target image acquisition module 340, and a second target image acquisition module 350. The initial image acquisition module 310 is configured to acquire a first display image displayed by the first spatial light modulator based on a preset image when the projection device is locally dimmed. The thermal load acquisition module 320 is configured to obtain a first thermal load of the first spatial light modulator according to the first display image. The thermal load balancing module 330 is configured to adjust the output power of the first spatial light modulator if the first thermal load is higher than a first heat resistance of the first spatial light modulator. The first target image acquisition module 340 is configured to obtain a first target image for display on the first spatial light modulator after the output power is adjusted according to the adjusted output power of the first spatial light modulator. The second target image acquisition module 350 is configured to obtain a second target image for display on the second spatial light modulator according to the preset image and the first target image.

[0072] As an implementation, the initial image acquisition module 310 comprises a camera. When the projection device is locally dimmed, the camera acquires a first display image displayed by the first spatial light modulator based on a preset image and a second display image displayed by the second spatial light modulator based on the preset image. According to the first display image and the second display image, a transfer relationship between the first display image and the second display image is obtained as follows:

[0073] I 21 = T(I1),

[0074] wherein I1 is the first display image, I 21 is a distribution image of the output light of the first spatial light modulator on the second spatial light modulator.

[0075] The thermal load acquisition module 320 obtains a first exit power of the first spatial light modulator according to the color and brightness of the first display image acquired by the camera, and obtains a second exit power of the second spatial light modulator according to the color and brightness of the second display image. The first transmittance, the first absorptivity, and the first exit power of the first spatial light modulator and the maximum output power of the light source are brought into an absorption power calculation formula of the first spatial light modulator to calculate the first thermal load of the first spatial light modulator. The absorption power calculation formula of the first spatial light modulator comprises:

[0076] H1= (1- η1) W in + a1(η1W in -Wout,1 ),

[0077] wherein H1 represents the first heat load of the first spatial light modulator; η1 represents the first transmittance of the first spatial light modulator; a1 represents the first absorptance of the first spatial light modulator; W out,1 represents the first exit power of the first spatial light modulator.

[0078] The heat load balancing module 330 adjusts the output power of the first spatial light modulator according to the preset output power value stored in the heat load balancing module when the first heat load of the first spatial light modulator is higher than the first heat resistance of the first spatial light modulator.

[0079] The first target image acquisition module 340 obtains the first target image for display on the first spatial light modulator after the output power is adjusted according to the adjusted output power of the first spatial light modulator; specifically, the adjusted output power value, the first exit power, the first absorptance, the first display image of the first spatial light modulator and the maximum output power of the light source are brought into the first target calculation formula to obtain the first target image for display on the first spatial light modulator after the output power is adjusted, and the first target calculation formula is:

[0080]

[0081] wherein I1 is the first display image of the first spatial light modulator based on the preset image display; I1' is the first target image for display on the first spatial light modulator after the output power is adjusted; ΔW is the adjusted output power value of the first spatial light modulator; W out,1 is the first exit power of the first spatial light modulator; η1 is the first absorptance of the first spatial light modulator; W0 is the maximum input power of the light source.

[0082] The second target image acquisition unit 350 calculates the first target image by using the transfer relationship formula to obtain the distribution image of the output light of the first spatial light modulator on the second spatial light modulator after the output power of the first spatial light modulator is adjusted, and the transfer relationship formula is:

[0083] I 21 ' = T(I1'),

[0084] wherein I 21 ' is the distribution image of the output light of the first spatial light modulator on the second spatial light modulator after the output power of the first spatial light modulator is adjusted, and I1' is the first target image.

[0085] The distribution image of the output light of the first spatial light modulator on the second spatial light modulator and the preset image are calculated by using a second target calculation formula, to obtain a second target image for display on the second spatial light modulator, wherein the second target calculation formula is:

[0086] I2' = I0 / I 21 ',

[0087] wherein I 21 ' is the distribution image of the output light of the first spatial light modulator on the second spatial light modulator after adjusting the output power of the first spatial light modulator, I2' is the second target image, and I0 is the preset image.

[0088] Referring to Figure 4 Another embodiment of the present application provides a projection device 400, which comprises a first spatial light modulator 410, a second spatial light modulator 420, a display 430, one or more processors 440, a memory 450, and one or more application programs. The first spatial light modulator 410 and the second spatial light modulator 420 are connected in series, and are used for local dimming of the projection device 400; the display 430 is used for displaying images; the one or more application programs are stored in the memory 450 and are configured to be executed by the one or more processors 440, and the one or more programs are configured to perform the method for local dimming and heat load balancing.

[0089] In some embodiments, the projection device 400 further comprises a light source, which is used for incident light to the first spatial light modulator 410 and the second spatial light modulator 420.

[0090] Referring to Figure 5Some embodiments of the present application include a computer readable storage medium 500 comprising program code 510 for performing the steps of the methods according to the embodiments of the present application. For example, one or more processors in the display or an image data processor upstream of the display can implement a method of local dimming heat load balancing according to an embodiment of the present application by executing software instructions in a program memory accessible to the processor. The present application can also be provided in the form of a program product. The program product can include any medium that carries a set of computer-readable signals comprising instructions which, when executed by a data processor, cause the data processor to execute a method of the present application. The program product according to the present application can be in any of a wide variety of formats. The program product can comprise, for example, non-transitory physical media such as magnetic data storage media (including floppy diskettes, hard disk drives), optical data storage media (including CD- ROMs, DVDs), electronic data storage media (including ROMs, Flash memory), and the like. The computer-readable signals on the program product can optionally be compressed or encrypted.

[0091] Finally, it should be noted that the above-mentioned embodiments are merely used to illustrate the technical solutions of the present application, rather than limit the present application; even though the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part of the technical features; and these modifications or replacements do not drive the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for balancing thermal loads in local dimming, characterized in that: Applied to a projection device including a first spatial light modulator and a second spatial light modulator, the method includes: acquiring a first display image displayed by the first spatial light modulator based on a preset image when local dimming is performed on the projection device; obtaining a first thermal load of the first spatial light modulator according to the first display image; If the first heat load is higher than a first heat tolerance of the first spatial light modulator, adjusting the output power of the first spatial light modulator; According to the adjusted output power of the first spatial light modulator, obtaining a first target image for display on the first spatial light modulator after adjusting the output power; A second target image for display on the second spatial light modulator is obtained according to the preset image and the first target image.

2. The method according to claim 1, characterized in that The projection device further includes a light source. If the first heat load is higher than a first heat resistance of the first spatial light modulator, the method further includes: adjusting the brightness of the light source incident on the first spatial light modulator; The step of obtaining, based on the adjusted output power of the first spatial light modulator, a first target image for display on the first spatial light modulator after adjusting the output power, includes: According to the adjusted output power of the first spatial light modulator and the adjusted brightness of the light source incident to the first spatial light modulator, a first target image is obtained for display on the first spatial light modulator after adjusting the output power of the first spatial light modulator and the adjusted brightness of the light source incident to the first spatial light modulator.

3. The method according to claim 2, characterized in that If the first heat load is higher than a first heat tolerance of the first spatial light modulator, adjusting the output power of the first spatial light modulator includes: If the first heat load is higher than a first heat tolerance of the first spatial light modulator, adjusting the output power of the first spatial light modulator according to a preset output power value; The adjusting the brightness of the light source incident on the first spatial light modulator includes: The brightness of the light source incident on the first spatial light modulator is adjusted according to a preset light source reduction ratio value.

4. The method according to claim 3, characterized in that The preset output power value and the preset light source reduction ratio value are obtained in the following manner: Acquire a first display image displayed by the first spatial light modulator based on the preset image and a second display image displayed by the second spatial light modulator based on the preset image when local dimming is performed on the projection device; determining a first output power of the first spatial light modulator and a second output power of the second spatial light modulator according to the first display image and the second display image; The preset output power value and the preset light source reduction ratio value are obtained based on the first transmittance, first absorption rate, first heat resistance and first output power of the first spatial light modulator and the second transmittance, second absorption rate, second heat resistance and second output power of the second spatial light modulator and the maximum output power of the light source.

5. The method according to claim 4, characterized in that Obtaining the preset output power value and the preset light source reduction ratio value according to the first transmittance, first absorptivity, first heat resistance, and first output power of the first spatial light modulator, the second transmittance, second absorptivity, second heat resistance, and second output power of the second spatial light modulator, and the maximum output power of the light source, comprising: The first transmittance, first absorptivity, first heat resistance, and first output power of the first spatial light modulator, the second transmittance, second absorptivity, second heat resistance, and second output power of the second spatial light modulator, and the maximum output power of the light source are brought into the absorption power calculation formula of the spatial light modulator to calculate the preset output power value and the preset light source reduction ratio value, wherein the absorption power calculation formula includes: ， in, is the first transmittance of the first spatial light modulator, is the second transmittance of the second spatial light modulator, is the first absorptivity of the first spatial light modulator, is the second absorptivity of the second spatial light modulator, is a first heat resistance capability of the first spatial light modulator, a second heat resistance capability of the second spatial light modulator, is the maximum output power of the light source, is the first output power of the first spatial light modulator, is the second output power of the second spatial light modulator, Lower the scale value for the preset light source, is the preset output power value.

6. The method according to claim 4, characterized in that The step of obtaining, according to the adjusted output power of the first spatial light modulator, a first target image for display on the first spatial light modulator after adjusting the output power, comprises: Substitute the adjusted output power value of the first spatial light modulator, the first output power, the first absorptivity, the first display image, and the maximum output power of the light source into a first target calculation formula to obtain a first target image for display on the first spatial light modulator after the output power is adjusted, wherein the first target calculation formula includes: ， in, A first display image displayed by the first spatial light modulator based on a preset image; a first target image for display on the first spatial light modulator after adjusting the output power; is an adjusted output power value of the first spatial light modulator; is the first output power of the first spatial light modulator; is a first absorptivity of the first spatial light modulator; is the maximum input power of the light source.

7. The method according to claim 1, characterized in that Before obtaining a first thermal load of the first spatial light modulator according to the first display image, the method further includes: Acquire a first display image displayed by the first spatial light modulator based on a preset image and a second display image displayed by the second spatial light modulator based on the preset image when local dimming is performed on the projection device; obtaining a transfer relationship from the first display image to the second display image according to the first display image and the second display image; The obtaining, according to the preset image and the first target image, a second target image for display on the second spatial light modulator includes: A second target image for display on the second spatial light modulator is obtained according to the transfer relationship, the first target image and the preset image.

8. The method according to claim 7, characterized in that: The obtaining, according to the first display image and the second display image, a transfer relationship from the first display image to the second display image includes: According to a first pixel in the first display image and a second pixel in the second display image, a transfer relationship between the first pixel and the second pixel is obtained: ， in, for the first display image, It is a distribution image of the output light of the first spatial light modulator on the second spatial light modulator.

9. The method according to claim 8, characterized in that The step of obtaining a second target image for display on the second spatial light modulator according to the transfer relationship, the first target image, and the preset image includes: The first target image is calculated using the transfer relationship to obtain a distribution image of the output light of the first spatial light modulator on the second spatial light modulator after adjusting the output power of the first spatial light modulator. The transfer relationship is: ， in, After adjusting the output power of the first spatial light modulator, the distribution image of the output light of the first spatial light modulator on the second spatial light modulator is obtained. is the first target image; The distribution image of the output light of the first spatial light modulator on the second spatial light modulator and the preset image are calculated using a second target calculation formula to obtain a second target image for display on the second spatial light modulator, wherein the second target calculation formula is: ， in, is a distribution image of the output light of the first spatial light modulator on the second spatial light modulator after the output power of the first spatial light modulator is adjusted, is the second target image, is the preset image.

10. A device for balancing thermal loads in local dimming, applied to a projection device including a first spatial light modulator and a second spatial light modulator, comprising: an initial image acquisition module, configured to acquire a first display image displayed by the first spatial light modulator based on a preset image when local dimming is performed on the projection device; a thermal load acquisition module, configured to obtain a first thermal load of the first spatial light modulator according to the first display image; a thermal load balancing module, configured to adjust the output power of the first spatial light modulator if the first thermal load is higher than a first heat tolerance of the first spatial light modulator; A first target image acquisition module is configured to obtain, according to the adjusted output power of the first spatial light modulator, a first target image for display on the first spatial light modulator after adjusting the output power; The second target image acquisition module is configured to obtain a second target image for display on the second spatial light modulator according to the preset image and the first target image.

11. A projection device, characterized in that: include: a first spatial light modulator and a second spatial light modulator, wherein the first spatial light modulator and the second spatial light modulator are connected in series for local dimming; A display, configured to display a preset image; one or more processors; Memory; One or more application programs, wherein the one or more application programs are stored in the memory and configured to be executed by the one or more processors, and the one or more programs are configured to execute the method according to any one of claims 1 to 9.

12. The projection device according to claim 11, characterized in that: The projection device further includes a light source, which is used to emit light toward the first spatial light modulator and the second spatial light modulator.

13. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores program code, which can be called by a processor to execute the method according to any one of claims 1 to 9.

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