JP2018013656A - Projection type display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a projection type display device that achieves optimization of luminosity and increase in contrast in accordance with a picture signal and environment light without being affected by constraint on a quality.SOLUTION: An illumination optical device, which comprises: a light source that is capable of adjusting an amount of light; a variable diaphragm that is capable of shading a light flux emitted from the light source; and a light bulb that modulates the light flux of the light source, has: luminance information detection means that detects luminance information on an input picture signal; environment light detection means that detect luminosity of a surrounding environment; aperture ratio control means that controls an aperture ratio of the variable diaphragm; and light emitting-amount control means that controls an amount of light to be emitted from the light source. The aperture ratio control means is configured to adjust the amount of light so that a control range of the amount of light emitting is minimum on the basis of the luminance information, and when the environment light is indicative of a dark value, the light emitting-amount control means is configured to control the amount of light emitting so that the amount of light emitting is a prescribed value.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a projection display device, and more particularly to a projection display device that performs dimming control in order to achieve brightness optimization and contrast improvement.

  Conventionally, in a projection display device that projects an image by modulating light flux from a light source, the amount of projection light may be adjusted according to the image signal in order to optimize brightness, improve contrast, or suppress black float. It was. In the case of performing such light amount adjustment, as the adjusting unit, a dimming unit that adjusts the light amount of the light source or a light blocking unit that blocks and reduces the light flux has been used.

  In Patent Document 1, when adjusting the amount of light based on a video signal, either one of the light control means and the light shielding means is used in combination. There has been disclosed a projection-type image display device in which the range of brightness that can be adjusted is widened by combining the light control means and the light shielding means, and further improvement of contrast and suppression of black float are realized.

  In Patent Document 2, the adjustment light quantity is set from the video signal, the dimming range is set from the usage information, and the adjustment of the light quantity exceeding the dimming range is prohibited, which is suitable for the type of video and the brightness of the surrounding environment. An illumination device that can provide a large amount of projected light is disclosed.

Japanese Patent No. 4011091 Japanese Patent No. 3661692

  However, the light amount adjustment combining the light control means and the light shielding means in Patent Document 1 is effective when the projection environment is dark, but when the projection environment is bright, if the adjustment is made in the same way as the dark environment, the contrast is rather low due to insufficient brightness. You may feel a drop in

  Further, in Patent Document 2, it is possible to suppress the influence due to excessive adjustment, but wide light amount adjustment as in Patent Document 1 becomes difficult. Further, when the dimming means is used in accordance with the video signal, it is difficult to manage the temperature of the light source for continuously changing video signals (movies, television programs, etc.). When it is difficult to control the temperature of the light source, the dimming range is further limited due to the quality restrictions against temperature changes in light sources such as high-pressure lamps and solid light sources.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a projection display device that achieves brightness optimization according to a video signal and ambient light while satisfying quality constraints. Another object is to suppress black float by improving contrast. Furthermore, another object is to facilitate temperature management and further reduce power consumption.

In order to achieve the above object, a projection display device according to the present invention includes:
A projection display device comprising: a light source capable of adjusting a light amount; a variable aperture capable of blocking a light beam emitted from the light source; and a light valve that modulates the light beam of the light source; Brightness information detection means for detecting the ambient light, ambient light detection means for detecting the brightness of the surrounding environment, aperture ratio control means for controlling the aperture ratio of the variable diaphragm, and the emitted light quantity for controlling the light quantity emitted from the light source Control means, and the aperture ratio control means adjusts the light amount based on the luminance information so that the control range of the emitted light amount is minimized, and when the ambient light shows a dark value, The emitted light quantity control means controls the emitted light quantity to be a predetermined value.

  The first effect of the present invention can provide a projection display device that realizes optimization of brightness according to a video signal and ambient light without being restricted in quality. The second effect is to improve the contrast, thereby suppressing black float. Furthermore, the third effect is that power consumption can be reduced while suppressing temperature changes.

1 is a block diagram illustrating a schematic configuration of a projection display device according to Embodiment 1. FIG. The figure which shows the ratio of the incident light quantity with respect to the aperture ratio of the variable aperture_diaphragm | restriction which concerns on Example 1. FIG. 7 is a flowchart illustrating control of light amount adjustment according to the first embodiment. The figure which shows control of the light quantity adjustment which concerns on Example 1. FIG. The figure which shows the example of the adjustment value with respect to ambient light and an average luminance level which concerns on Example 1. FIG. FIG. 6 is a block diagram illustrating a schematic configuration of a projection display apparatus according to a second embodiment. 7 is a flowchart illustrating control of light amount adjustment according to the second embodiment. The figure which shows the relationship of the time-dependent change of the emitted time which concerns on Example 2, and emitted light quantity The figure which shows the correction method of the time-dependent change of the light quantity according to the environmental light which concerns on Example 2. FIG. FIG. 6 is a block diagram illustrating a schematic configuration of a projection display apparatus according to a third embodiment. 10 is a flowchart showing dimming control of a solid-state light source according to the third embodiment. The figure regarding the light quantity adjustment at the time of the multiple projection which concerns on Example 4. FIG. FIG. 6 is a block diagram illustrating a schematic configuration of a projection display apparatus according to a fourth embodiment.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The present invention is applicable to projection display devices such as liquid crystal projectors and DLP (Digital Light Processing) projectors.

  Hereinafter, a projection display apparatus according to a first embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 is a block diagram of a projection display device 1 according to the first embodiment of the present invention.

  The configuration of the projection display device 1 is shown below. Image analysis unit 110 as luminance information detection unit, environmental light sensor 120 as environmental light detection unit, aperture control unit 130 as aperture ratio control unit, lamp control unit 140 as emitted light amount control unit, aperture drive unit 150, lamp A drive unit 160 and a projection unit 170 are provided.

  The video analysis unit 110 includes a terminal for inputting various video signals such as an HDMI (registered trademark) signal, a DVI signal, and a component signal, and a receiver IC for receiving a video signal input through these terminals. Is provided. Further, the video analysis unit 110 adjusts the format of the video signal, and calculates a feature amount (hereinafter, luminance information) indicating the brightness of the video signal. The calculated luminance information is output to the aperture controller 130. Further, as the luminance information to be used, for example, the following three types can be considered.

  First, an average luminance level of a video signal will be described as first luminance information. For example, when the brightness of each pixel of the video signal is indicated as 256 levels of luminance data, a value obtained by averaging the luminance data of the pixels included in one frame of the video signal is set as the average luminance level of the video signal.

  Next, the maximum luminance level of the video signal will be described as the second luminance information. For example, when the luminance data is represented as a 256-level luminance distribution (hereinafter, luminance histogram), the brightest value in the luminance histogram is the maximum gradation of the video signal.

  Furthermore, the divided luminance level of the video signal will be described as the third luminance information. For example, when a pixel included in one frame of the video signal is divided into blocks, the average luminance level of each block is calculated, and the maximum value and the minimum value are set as the divided luminance level of the video signal.

  Note that the luminance information acquisition range is not limited to all pixels included in one frame, but may be acquired from the center, a part of the screen, or the like. In the present embodiment, the description will be made using the average luminance level. However, the above method is merely an example, and the scope of the present invention is not limited to them.

  The ambient light sensor 120 detects the illuminance (hereinafter, ambient light) of the surrounding environment of the projection display device 1. The ambient light sensor 120 is provided on the surface of the projection display device 1. The installation position of the ambient light sensor 120 is not limited to this, and may be installed around the projection display device. The detected ambient light is output to the lamp controller 140.

  Based on the average luminance level given from the video analysis unit 110, the aperture control unit 130 drives the aperture so that the aperture ratio increases when the video signal is bright and the aperture ratio decreases when the video signal is dark. An aperture ratio is designated in the part 150.

  Based on the ambient light provided from the ambient light sensor 120, the lamp controller 140 increases the supply power in a bright environment and reduces the supply power in a dark environment. In 160, supply power is designated. The control based on the ambient light given from the ambient light sensor 120 may be replaced by a user operation.

  The diaphragm driving unit 150 and the lamp driving unit 160 drive the variable diaphragm 173 and the lamp 174 based on the designated values.

  The projection unit 170 includes a projection optical system 171, a liquid crystal panel 172, a variable diaphragm 173, and a lamp 174. A light beam emitted from the lamp 174 passes through the variable diaphragm 173, is modulated by the liquid crystal panel 172, and passes through the projection optical system 171. Through the screen 9.

  The projection optical system 171 can perform zooming, shifting, focusing, and the like optically by operating the lens unit with a motor.

  The liquid crystal panel 172 is a light valve that modulates a light beam. As the incident angle of the incident light beam increases, black floating occurs and the contrast decreases.

  The variable diaphragm 173 is installed between the light source 174 and the liquid crystal panel 172, and can adjust the amount of light incident on the liquid crystal panel 172 by increasing or decreasing the aperture ratio of the diaphragm.

  The aperture ratio of the diaphragm is driven by the diaphragm driver 150.

  FIG. 2 shows the ratio of the amount of light incident on the liquid crystal panel 172 when the aperture ratio of the variable diaphragm 173 changes from 0 to 100%.

  According to the figure, the amount of incident light also decreases as the aperture ratio of the diaphragm decreases. Further, the reduction of the aperture ratio can reduce the incident angle at which the passing light beam enters the liquid crystal panel 172. Therefore, by changing the aperture ratio of the variable diaphragm 173, not only the brightness of the projected image can be adjusted, but also the suppression of black float can be realized.

  The lamp 174 can adjust the amount of light emitted from the lamp 174 by increasing or decreasing the supplied power. The supply power is adjusted by the lamp driving unit 160. Further, when the lamp 174 is a high-pressure lamp such as a high-pressure mercury lamp, if the lamp 174 is driven for a certain period of time in a low power state, blackening or flickering occurs due to a temperature drop inside the high-pressure lamp, resulting in a decrease in life and image quality. . However, when dimming by reducing the supplied power within the constraints on quality, the power consumption can be reduced, and therefore the dimming control of the high-pressure lamp needs to be performed within the constraints.

  FIG. 3 shows a flowchart of control of the variable diaphragm 173 and the lamp 174 performed by the diaphragm controller 130 and the lamp controller 140. The flow shown in FIG. 3 is assumed to be started every certain time (for example, 100 milliseconds). FIG. 4 is a diagram showing the control performed in this flow. According to the figure, in a bright environment, the control of the video signal is performed using the dimming of the lamp 174 to the minimum and mainly using the aperture ratio control of the variable diaphragm 173. On the other hand, in the case of a dark environment, the light amount is first lowered to a predetermined value with respect to the ambient light by using the dimming of the lamp 174. The control for the video signal is performed in the same manner as in a bright environment below the predetermined value.

  This flow will be described in the order of control according to ambient light and control according to luminance information.

  First, in this flow, in order to control the lamp with respect to the ambient light, the ambient light given from the ambient light sensor 120 is acquired in S110.

  Subsequently, in S120, as shown in FIG. 5A, the lamp control unit 140 instructs the lamp driving unit 160 to increase the supply power in a bright environment and decrease the supply power in a dark environment. For example, when the ambient light is 200 lx, the lamp control unit 140 specifies the supply power 280 W to the lamp driving unit 160. In addition, regarding the restrictions on the quality of the high-pressure lamp, when the supply power is specified according to the environmental light as described above, the dimming control only needs to be performed for the environmental light even in the dimming range within the restrictions. Sufficient dimming is possible, and the effect of reducing power consumption is obtained in a dark environment.

  Subsequently, in S130, it is determined whether or not the supplied power is a specified value, and the lamp is controlled in S140.

  The lamp control in S140 determines whether or not to increase the supply power in S141, and increases or decreases the supply power in S142 and S143.

  In addition, since the ambient light is less frequently changed than the video signal, the control frequency of the lamp 174 is reduced, and temperature management is facilitated.

  According to the above flow, the brightness of the projected image is adjusted with respect to the brightness of the surrounding environment, and the control range and control frequency of the lamp are limited.

  Subsequently, in this flow, in order to control the variable aperture and the lamp with respect to the luminance information, the average luminance level given by the video analysis unit 110 is acquired in S150.

  Subsequently, in S160, the aperture controller 130 controls the aperture ratio so that the emission light amount adjustment range of the lamp controller 140 is minimized. As shown in FIG. 5B, the aperture driving unit 150 is designated so that the aperture ratio increases when the average brightness level is high and the aperture ratio decreases when the average brightness level is low. For example, when the average luminance level is 70, the aperture control unit 130 specifies an aperture ratio of 53% for the aperture drive unit 150. Also, by reducing the aperture ratio for dark images, the angle of incidence on the liquid crystal panel 172 can be reduced, and black float can be suppressed. Contrast can be improved while adjusting to an arbitrary brightness. An effect is obtained.

  Subsequently, in S170, it is determined whether or not the aperture ratio is a specified value. In S180, the variable aperture is controlled.

  In the variable aperture control in S180, it is determined whether to increase the aperture ratio in S181, and the aperture ratio is increased or decreased in S182 and S183.

  When the aperture ratio is decreased in S183, the aperture ratio is decreased at a constant rate (for example, 1%) so as not to be aware of the change in the aperture ratio. Further, the supply power is controlled in S190 as necessary.

  According to the above flow, there is an effect that the brightness of the projected image is adjusted with respect to the brightness of the video signal, and the advantage of using the variable aperture for light amount adjustment is enhanced.

  Hereinafter, a projection display device according to a second embodiment of the present invention will be described with reference to FIGS.

  By adopting the following configuration, it is possible to obtain effects such as optimization of brightness and improvement of contrast with respect to deterioration over time of the light source. The same parts as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 6 is a block diagram of the projection display device 2 according to the second embodiment of the present invention.

  The difference between the projection display device 2 and the projection display device 1 is that the video analysis unit 110 is the video analysis unit 210, the ambient light sensor 120 is the ambient light sensor 220, the aperture control unit 130 is the aperture control device 230, and the lamp control. The unit 140 is replaced with a lamp control unit 240, and includes an emitted light amount detection unit 280 as an emitted light amount detection unit.

  The video analysis unit 210 outputs the calculated brightness information to the lamp control unit 240 in addition to the function of the video analysis unit 110.

  The ambient light sensor 220 outputs the detected ambient light to the aperture controller 230 in addition to the function of the ambient light sensor 120.

  The emitted light amount detection unit 280 detects the amount of light emitted from the lamp 174 in order to acquire information on deterioration of the lamp 174 over time. The emitted light quantity detector 280 is provided inside the projection display device 2. Further, the installation position of the emitted light quantity detection unit 280 is not limited to this, and may be installed around the projection display device. Furthermore, the emitted light quantity detection unit 280 is a timer that measures the emission time, and may calculate the emitted light quantity from the measured emission time. The detected amount of emitted light is output to the aperture controller 230 and the lamp controller 240.

  The aperture control unit 230 provides an aperture ratio to the aperture driving unit 150 based on the average luminance level given from the video analysis unit 210, the ambient light given from the ambient light sensor 220, and the outgoing luminance given from the outgoing light quantity detection unit 280. Is specified.

  The lamp control unit 240 supplies power to the lamp driving unit 160 based on the average luminance level given from the video analysis unit 210, the ambient light given from the ambient light sensor 220, and the emitted light amount given from the emitted light amount detection unit 280. Is specified.

  FIG. 7 shows a flowchart of control of the variable diaphragm 173 and the lamp 174 performed by the diaphragm controller 230 and the lamp controller 240.

  The flow shown in FIG. 7 is assumed to start every certain time (for example, 100 milliseconds). This flow will be described in the order of control according to ambient light and changes with time, and control according to luminance information.

  First, in this flow, the ambient light provided from the ambient light sensor 220 is acquired in S210 in order to control the lamp with respect to ambient light and a change with time.

  Subsequently, in S211, the emitted light quantity given from the emitted light quantity detection unit 280 is acquired.

  Subsequently, in S212, as shown in FIG. 8, it is determined whether or not the acquired amount of emitted light is greater than or equal to a predetermined value (for example, 95%).

  If the condition is satisfied, the average luminance level given by the video analysis unit 110 in S213 is acquired, and the lamp control unit 240 increases the supply power in a bright environment and decreases the supply power in a dark environment. The drive unit 160 is designated. However, when the average luminance level is a sufficiently bright image such as 196 or more in 256 stages, the eco control is designated to the lamp driving unit 160.

  If the condition is not satisfied, the amount of emitted light is set in accordance with the ambient light in S221, and the decrease in the amount of light due to changes with time is adjusted in accordance with the ambient light in S222 as shown in FIGS. It is determined whether or not correction can be performed using light control.

  If the condition is satisfied, in S223, as shown in FIG. 9 (a), supply power that corrects the light amount reduced due to the change with time is specified to the lamp driving unit 160.

  If the condition is not satisfied, in S224, a value that maximizes the aperture ratio of the variable diaphragm 173 without specifying the supply power in order to prioritize the luminance as shown in FIG. 9B. Is designated to the aperture driving unit 150. Therefore, as shown in FIG. 9A, when the light amount decrease due to light control is larger than the light amount decrease due to change over time, it is possible to project without being affected by the change over time.

  Even when the above conditions are not satisfied, brightness optimization is realized by switching to eco control or luminance priority control.

  Subsequently, in S231, it is determined whether or not the supplied power is a specified value, and the lamp is controlled in S240. The lamp control in S240 determines whether or not to increase the supply power in S241, and increases the supply power in S242.

  In S243, it is determined whether or not eco-control is designated. If eco-control is designated, in S244, the user can reduce the supplied power at a speed that does not feel a change due to dimming. Therefore, it is possible to reduce power consumption without making eco-control aware.

  If eco-control is not designated, normal supply power reduction processing is performed in S245.

  Subsequently, in this flow, in order to control the variable aperture and the lamp with respect to the luminance information, in S251, the aperture controller 230 controls the aperture ratio so that the emission light amount adjustment range of the lamp controller 240 is minimized. I do. When the average luminance level is high, the aperture ratio increases, and when the average luminance level is low, the aperture driving unit 150 is specified so that the aperture ratio decreases.

  Subsequently, in S252, it is determined whether or not the aperture ratio is a specified value. In S280, the variable aperture is controlled, and in S290, the lamp is controlled.

  According to the above flow, the light amount is adjusted according to the temporal change of the light amount in addition to the ambient light, and the power consumption is reduced when not corrected, and the brightness is projected with priority when it cannot be corrected. Can provide light intensity adjustment.

  Hereinafter, a projection display apparatus according to a third embodiment of the present invention will be described with reference to FIGS.

  By adopting the following configuration, even when the light source is a solid light source, an effect of minimizing temperature change can be obtained. The same parts as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 10 is a block diagram of a projection display device 3 according to the third embodiment of the present invention.

  The difference between the projection display device 3 and the projection display device 1 is that the lamp control unit 140 is replaced with a solid light source control unit 340, the lamp drive unit 160 is replaced with a solid light source drive unit 360, and the lamp 174 is replaced with a solid light source 374. Temperature sensor 381 is provided.

  The temperature sensor 381 is provided to detect the temperature of the solid light source 374, and the detected temperature of each solid light source is output to the solid light source control unit 340.

  In addition to the function of the lamp control unit 140, the solid light source control unit 340 specifies supply power to the solid light source driving unit 360 based on the temperature given from the temperature sensor 381. In addition, the solid light source driving unit 360 drives the solid light source 374 according to the designated value.

  In addition to the function of the lamp 174, the solid-state light source 374 has a feature that the lifetime is longer than that of the lamp light source. However, when dimming control or the like is performed, the lifetime, which is an advantage, is shortened at high temperatures. is necessary.

  FIG. 11 shows a flowchart of the control of the solid light source 374 according to the ambient light performed by the solid light source control unit 340.

  In addition to the flow performed by the ambient light lamp control unit 140, this flow performs control for temperature management of the solid light source.

  First, in S341, the light source temperature given from the temperature sensor 381 is acquired.

  Subsequently, in S342, it is determined whether or not the light source temperature is within a predetermined value. If the light source temperature is outside the predetermined value, the solid light source is not controlled.

  When the light source temperature is within the predetermined value, increase / decrease in supply power is determined in S343, and supply power is designated in S344 and S345.

  Since the light source temperature also changes as the supply power is greatly changed, the supply power is designated in several stages. For example, when changing from 360 W to 400 W, specify 4 W at a time. In addition, since ambient light does not change continuously like a video signal, the temperature can be kept within a predetermined range even when a plurality of solid state light sources are provided.

  According to the above flow, there is an effect that control and temperature management are facilitated by performing dimming control based on the light source temperature only for environmental light having a low change frequency.

  Hereinafter, a projection display apparatus according to a fourth embodiment of the present invention will be described with reference to FIGS.

  By adopting the following configuration, it is possible to provide optimum brightness even when a projected image is superimposed on a plurality of projection display devices and projected as one image. The same parts as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted.

  When the projection is performed by each of the plurality of projection type display devices as shown in FIG. 12A, there is no problem even if the light amount is adjusted according to the video, but one projection video as shown in FIG. When the projection is performed, a difference in brightness occurs when the amount of light is adjusted according to the image. In particular, if there is a difference in brightness between the left and right, the superimposing portion will noticeably affect the image quality.

  Therefore, in order to prevent a difference in brightness when projecting in a superimposed manner, a control that does not cause a difference in brightness between the left and right projection images as shown in FIG. 12B will be described.

  FIG. 13 is a block diagram of a projection display device 4 according to the fourth embodiment of the present invention.

  The difference between the projection type display device 4 and the projection type display device 1 is that the aperture control unit 130 is replaced with an aperture control unit 430 and includes a correction determination unit 482.

  The correction determination unit 482 sets correction (for example, edge blending) for the superimposed portion to be displayed as one projection image as illustrated in FIG. 12C with respect to the superimposed portion as illustrated in FIG. Or when it is canceled, the information is notified to the aperture control unit 430.

  When the correction is set, the aperture control unit 430 designates an aperture ratio that is the maximum value for the aperture driving unit 150, and prohibits the aperture control until the correction is canceled.

  As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to these embodiment, A various deformation | transformation and change are possible within the range of the summary.

DESCRIPTION OF SYMBOLS 1 Projection type display apparatus, 110 Image | video analysis part, 120 Ambient light sensor,
130 Aperture control unit, 140 Lamp control unit, 172 LCD panel, 173 Variable aperture,
174 lamp

Claims (7)

A light source with adjustable light intensity;
A variable stop capable of blocking the light beam emitted from the light source;
A light valve that modulates the luminous flux of the light source;
A projection display device comprising:
Luminance information detecting means for detecting luminance information of the input video signal;
Ambient light detection means for detecting the brightness of the surrounding environment;
An aperture ratio control means for controlling an aperture ratio of the variable diaphragm;
An emitted light amount control means for controlling the amount of light emitted from the light source,
The aperture ratio control means is based on the luminance information.
While adjusting the light amount so that the control range of the emitted light amount is minimized,
When the ambient light shows a dark value, the emitted light amount control means,
A projection-type display device, wherein the amount of emitted light is controlled to be a predetermined value. An emitted light amount detecting means for detecting the emitted light amount of the light source;
The emitted light quantity control means has an emitted light quantity value detected by the emitted light quantity detector.
When it is larger than the emitted light quantity value controlled by the emitted light quantity control means,
The projection display device according to claim 1, wherein the amount of emitted light is increased so as to compensate for a change in the amount of light source with time. The aperture ratio control means includes
The emitted light quantity value detected by the emitted light quantity detection means is
When it is smaller than the emitted light quantity value set by the emitted light quantity control means,
3. The projection display device according to claim 2, wherein the aperture ratio is fixed to a maximum value or controlled within a range in which a light shielding amount is reduced. The emitted light quantity value detected by the emitted light quantity detection means is larger than a predetermined value,
The ambient light detected by the ambient light detection means shows a value brighter than a predetermined value,
When the brightness detected by the brightness information detecting means is greater than a predetermined value,
4. The projection type display device according to claim 2, wherein the emitted light quantity control means reduces the emitted light quantity value in a stepwise manner. The projection type display device according to any one of claims 2 to 4, wherein the emitted light quantity detection means calculates an emitted light quantity value based on a lighting time of the light source. Temperature detecting means for detecting the temperature of the light source;
When the light source is a plurality of solid light sources,
According to the temperature detected by the temperature detection means, the change of the emitted light amount value,
The projection display device according to claim 1, wherein the projection display device is controlled so as to maintain a predetermined temperature. The aperture ratio control means controls the aperture ratio to be a maximum value when the projection display apparatus projects one image superimposed on a projection image of another projection display apparatus. The projection display device according to claim 1.