JPH0984036A - Projection display device, multi-display device using it and multi-display system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To adjust luminance and a white balance by a projection display device itself. SOLUTION: A luminance adjustment circuit 9 and white balance adjustment circuits 10R, 10G, 10B are adjusted by a proper means to apply initial adjustment of luminance and a white balance. Then a pattern generating means 6 is used to display an adjustment pattern on a transparent screen 3 and it is picked up by a video camera 4 and a luminance level of a pupil image of projection lenses 2R, 2G, 2B appearing on the transparent screen 3 from the output is stored in a storage device 15. In the case of read-adjustment of the luminance and the white balance, similarly the luminance level of the pupil image of the projection lenses 2R, 2G, 2B is detected and the detection level is compared with a reference luminance level stored in the storage device 15 by a control circuit 16 to control a luminance adjustment circuit 9 and white balance adjustment circuits 10R, 10G, 10B depending on the arithmetic result.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection display device, and more particularly to a projection display device which automatically adjusts brightness and white balance.

[0002]

2. Description of the Related Art In a projection display device, for example, a rear projection type projection display device using a cathode ray tube, as shown in FIG. 18, a cathode ray tube 1R for displaying images of red, green, and blue light beams is used. , 1G, 1B and a projection lens 2 provided for each of these cathode ray tubes 1R, 1G, 1B
It is composed of R, 2G, 2B and a transmissive screen 3. The projected images of the red, green and blue cathode ray tubes 1R, 1G and 1B are magnified by the projection lenses 2R, 2G and 2B, respectively, and projected on the transmission screen 3 so as to form an image on the emission side of the transmission screen 3. , By this, the color image is enlarged and displayed there.

In such a projection type display device, there is known an automatic adjustment technique such as white balance for adjusting the ratio of the light amounts of red, green and blue images. It is disclosed in Japanese Patent No. 15692.

In such a technique, an optical transmission / reflector for reflecting a part of the image light emitted from the projection / magnification display device is provided between the projection / magnification display device and the screen, and the reflected light is not imaged or formed. The image formed on the optical transmission / reflector is imaged by the image sensor to calculate the error value for each color, and the white balance, brightness, and convergence of the projection display device are automatically corrected according to the error value. To do.

[0005]

By the way, in the above-mentioned prior art, when a typical CCD camera is used as the image pickup device, noise is increased under low illuminance conditions, so that white balance and luminance can be accurately adjusted. In order to be able to adjust the above, it is necessary to increase the reflectance of the above optical transmission / reflector. However, when the reflectance of the optical transmission / reflector is increased, the amount of transmitted light is reduced, the image appearing on the viewing side of the transmissive screen becomes darker, and there is a problem that the image quality deteriorates such as uneven brightness. It was

Further, in the above-mentioned prior art, what is reflected by the above-mentioned optical transmission / reflector is not only a part of the image light emitted from the above-mentioned projection magnifying display device but also the image of the projection magnifying display device itself. Since it is also reflected, it is difficult to adjust the white balance and brightness by extracting only the image light reflected by the optical transmission / reflector in the portion where the virtual image of the projection magnification display device itself is observed in the image sensor. There was a problem.

Further, conventionally, the deterioration of the adjustment accuracy due to the influence of the incident light from the outside of the projection display apparatus, that is, the outside light is not taken into consideration, and the automatic adjustment is performed depending on the intensity and the color of the outside light at the time of the adjustment. There is also a problem that the brightness and white balance of the adjusted projection display device change.

An object of the present invention is to solve such a problem and to eliminate the above-mentioned optical transmission / reflector so that the white balance and the brightness can be automatically adjusted with high accuracy and in a short time. Another object of the present invention is to provide a projection display device capable of reducing the influence of external light, and a device and system using the same.

[0009]

In order to achieve the above object, the present invention provides a transmissive screen which reflects a part of irradiation light, and a pattern generation for generating an image pattern for adjustment on the transmissive screen. Means, a projection magnifying device for projecting image light by the projection lens, detection means for detecting the amount of light of the pupil image of the projection lens specularly reflected by the transmissive screen, and red, green, and blue of the projection magnifying device, respectively. Luminance adjusting means for simultaneously adjusting the output light amount of the
White balance adjusting means for adjusting the output light amount of each blue, control means for controlling the brightness adjusting means and the white balance adjusting means, and reference brightness levels or brightness of red, green and blue components of the pupil image of the projection lens. First storage means for storing a ratio, the reference brightness level stored in the first storage device, and the brightness levels of the red, green, and blue components of the pupil image of the projection lens detected by the detection element. And a comparison calculation means for comparing and calculating
The control means controls the brightness adjusting means and the white balance adjusting means according to the comparison result of the comparison calculating means.

Further, according to the present invention, a second storage means for storing an output brightness level of the detecting means when the projection enlarging device does not emit image light, and the transmission type screen by the pattern generating means. The subtraction means for subtracting the brightness level stored in the second storage means from the brightness level detected from the output of the detection means when the image pattern for adjustment is displayed is provided. The output is supplied to the first storage means and the comparison calculation means.

[0011]

According to the present invention, for example, after the initial adjustment is completed at the time of factory shipment, as an initial setting, an image pattern for adjustment is displayed on the transmissive screen by the pattern generating means, and the pupil image of the projection lens at that time is displayed. The brightness level is detected by the detection means and stored as the reference brightness level in the first storage means. In the readjustment after the initial setting, the image pattern for adjustment of the pattern generating means is again displayed on the transmissive screen, and the brightness level of the pupil image of the projection lens at that time is detected by the detecting means. The reference brightness level stored in the first storage means is subjected to comparison calculation, and the control means controls the brightness adjustment means and the white balance adjustment means according to the comparison calculation result. As a result, the brightness and white balance of the projection display device are automatically adjusted to those at the time of initial setting.

Further, the output brightness level of the detecting means in a state where the image light is not emitted from the projection enlarging device is due to external light, which is stored in the second storage device and is set at the time of initial setting. At the time of readjustment, the brightness level stored in the second storage means is subtracted from the output brightness level of the detection means by the subtraction means, so that the initial setting and the automatic adjustment of brightness and white balance affect external light. Instead, high-precision automatic adjustment becomes possible.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a first embodiment of a projection type display device according to the present invention.
1B is a cathode ray tube for displaying red (R), green (G), and blue (B) images, 2R, 2G, and 2R are cathode ray tubes 1R,
Projection lenses for each of 1G and 1B, 3 is a transmissive screen, 4
Is a video camera, 5R, 5G and 5B are virtual images of the pupils of the projection lenses 2R, 2G and 2B appearing on the projection screen 3 (hereinafter referred to as projection lens pupil images), 6 is a pattern generator, 7 is a switch, and 8 is a signal. A processing circuit, 9 is a brightness adjustment circuit, 10R, 10G and 10B are white balance adjustment circuits, 1
1 is an input terminal of a video signal, 12 is a drive adjustment circuit, 1
3 is a cutoff adjustment circuit, 14 is an A / D converter, 15 is a storage device, 16 is a control circuit, 17 is a frame memory, 1
Reference numeral 8 is a projection display device.

In this embodiment, a projection magnifying device is composed of three RGB cathode ray tubes and a projection lens, and an image of the cathode ray tube magnified by the projection lenses is projected on the projection type screen from its rear side. This is an example of a rear projection display device of the RGB three-tube projection system.

In FIG. 1, a projection display device 1
In 8, the video signal is input from the outside through the input terminal 11, and the pattern generator 6 outputs the video signal such as the adjustment pattern. The video signal from the outside and the video signal from the pattern generator 6 are switched and selected by the switch 7, and subjected to predetermined processing and separation into color signals by the signal processing circuit 8 and then supplied to the brightness adjusting circuit 9. To be done. The brightness adjustment circuit 9 is controlled by the control circuit 16 for brightness adjustment. For example, by adjusting the DC (direct current) level of the video signal from the signal processing circuit 8 to adjust the brightness, the CRT 1R, The amounts of red, green, and blue lights emitted from 1G and 1B are adjusted simultaneously.

A color signal R output from the brightness adjusting circuit 9,
G and B are respectively supplied to the corresponding white balance adjusting circuits 10R, 10G, and 10B provided for the respective cathode ray tubes 1R, 1G, and 1B, and white balance adjustment for adjusting the light amount of each of the cathode ray tubes 1R, 1G, and 1B. Is done. The white balance adjusting circuits 10R, 10G, and 10B include a drive adjusting circuit 12 for adjusting a white balance of high brightness and a cutoff adjusting circuit 13 for adjusting a white balance of low brightness in a cathode ray tube projection display device. Composed of.

The white balance adjusting circuits 10R and 10
Each cathode ray tube 1R, 1 by the output signal of G, 10B
G, 1B are driven, and the red image, green image, and blue image projected on each are magnified by the projection lenses 2R, 2G, 2B and projected on the projection screen 3 from the rear side.

The projection screen 3, for example, as shown in FIG. 2, is constructed by laminating a Fresnel lens 17 and a lenticular lens 18, and the cathode ray tubes 1R, 1
The image light emitted from the projection magnifying device composed of G, 1B and the projection lenses 2R, 2G, 2B is transmitted to form an image.

By the way, in the projection display device of the conventional RGB three-tube projection system, the incident light is specularly reflected on the image light incident side of the transmissive screen 3 and the projection lens pupil images 5R, 5 are formed.
G and 5B appear.

In this embodiment, the projection lens pupil image 5
In order to eliminate R, 5G and 5B and to perform brightness adjustment and white balance adjustment with high accuracy, the following device is provided together with the pattern generator 6.

That is, in order to obtain the information of the projection lens pupil images 5R, 5G, 5B, a video camera 4 for picking up the transmissive screen 3 (other image pickup elements may be used), and an output signal of the video camera 4 is converted into a digital signal. A / D conversion circuit 14 for converting into a frame, a frame memory 17 for storing the output signal of the A / D conversion circuit 14, and the brightness levels of the red, green, and blue signal components of the projection lens pupil images 5R, 5G, 5B as reference brightness. Necessary data is taken out from the storage device 15 to be stored as a level and the frame memory 17 and operated, and compared and operated with the reference luminance level stored in the storage device 15. Based on the result, the white balance adjusting circuit 10R, 10G, 10B or a control circuit 16 for controlling the brightness adjusting circuit 9 is provided.

The method of adjusting the brightness and white balance in this embodiment will be described below.

First, initialization is performed before the main adjustment is performed. This initial setting is performed after the initial adjustment, that is, after the adjustment of the white balance and the brightness level as viewed from the image light emission side of the transmissive screen 3 which is performed at the time of factory shipment. This initial adjustment may be performed manually by providing a variable resistor or the like in the brightness adjusting circuit 9 and the white balance adjusting circuits 10R, 10G, 10B, or by using a remote controller or the like. In addition, the transmissive screen 3
A video camera is installed in front of the projector, and the brightness adjustment circuit 9 and the white balance adjustment circuits 10R, 10G, and 10B are controlled by using the white balance adjustment function of the video camera. The balance may be initially adjusted.

The state at the time when the above-described initial adjustment of the brightness and white balance is completed is set as an initial state, and the initial setting is performed in this initial state.

In this initial setting, the switch 7 is switched to the pattern generating means 6 side. This pattern generation means 6
Is, for example, 10R, 1 for high brightness white balance adjustment.
A white raster signal of 0G, 10B0% brightness is output. The white raster signal is processed by the signal processing circuit 8, the brightness adjusting circuit 9 and the white balance adjusting circuits 10R, 10G, 10B and converted into an appropriate video signal, and each cathode ray tube 1R, 1G,
The image of white raster is projected on the transmissive screen 3 by being supplied to 1B.

Generally, the transmissive screen 3 transmits most of the incident image light. However, although it is a few%, there is reflection on the image light incident side of the transmissive screen 3, for example, the plane on the incident side of the Fresnel lens 18 or the inside of the convex lens surface, and the image is projected on the image light incident side of the transmissive screen 3. Lens pupil images 5R, 5G, 5B are produced.

The video camera 4 takes an image of the projection screen 3 displaying the image of the white raster from the image light incident side. The output signal of the video camera 4 is A / D conversion means 14
After being converted into a digital signal by the frame memory 17
Stored in. The control circuit 16 uses the frame memory 1
From the digital signal stored in 7, the projection lens pupil image 5
The brightness levels of the signal components of R, 5G, and 5B are extracted,
These luminance levels or their level ratio (luminance ratio)
Is stored in the storage device 15 as the reference luminance level of each of the projection lens pupil images 5R, 5G, 5B.

With the above, the initial setting operation is completed, and the switch 7
To the input terminal 11 side. As a result, the image of the image signal from the input terminal 11 is enlarged and displayed on the transmissive screen 3 with the brightness and white balance adjusted.

Thereafter, when the white balance is readjusted, the switch 7 is switched to the pattern generating means 6 side again. The pattern generating means 6 operates in the same manner as at the time of initial setting.
A white raster signal of 0% brightness is output, and as a result, a white raster image is displayed on the transmissive screen 3 as described above. This image is picked up by the video camera 4, the output signal of the video camera 4 is converted into a digital signal by the A / D conversion means 14, and the digital signal is stored in the frame memory 17.

The control circuit 16 selects from among the digital signals stored in the frame memory 17 the projection lens pupil image 5R,
The luminance levels of 5G and 5B are extracted, and this luminance level or luminance ratio is compared with the reference luminance level or luminance ratio stored in the storage device 15 at the time of initialization. As a result, if they match, the adjustment ends. If they do not match, the control circuit 16 controls the white balance adjusting circuits 10R, 10G, and 10B according to the comparison result.

Here, as an example of this control method, when the white balance is adjusted by controlling only the white balance adjusting circuits 10R, 10G, and 10B, for example, the storage device 15 stores red, green, and blue luminances. The ratio is stored, and the brightness ratio and the red of the projection lens pupil images 5R, 5G, 5B at the time of readjustment,
By comparing the brightness ratios of green and blue and lowering the brightness levels of other colors with the brightness level of the color having the lowest brightness level as a reference, the brightness levels of other colors are matched. , The white balance at the time of initial setting can be reproduced.

Regarding the brightness, when adjusting this, the reference brightness levels of red, green, and blue are stored in the storage device 15, and these reference brightness levels and the projection lens pupil images 5R, 5G, 5B5 at the time of readjustment are stored. By comparing the brightness levels of red, green, and blue, and adjusting the white balance adjustment circuits 10R, 10G, and 10B so that the brightness levels match, the white balance and brightness level at the initial setting are reproduced. can do.

As described above, the white balance adjusting circuits 10R, 10
Although the adjustment of the brightness and the white balance using G and 10B has been described, the brightness is adjusted by the brightness adjustment circuit 9,
In addition, the white balance is adjusted by the white balance adjusting circuits 10R and 10R.
You may make it adjust by G, 10B. In this case, the storage device 15 stores the reference brightness levels of the projection lens pupil images 5R, 5G, 5B, and the white levels are stored until the brightness levels of the projection lens pupil images 5R, 5G, 5B at the time of initial setting and readjustment are extracted. This is the same as the adjustment only in the balance adjustment circuits 10R, 10G, and 10B. In this adjustment example, the projection lens pupil image 5
After extracting the brightness levels of R, 5G, and 5B from the frame memory 17, for example, if all the brightness levels of the extracted brightness levels are lower or higher than the reference brightness level stored in the storage device 15, The brightness adjusting circuit 9 adjusts the voltage amplitude or DC level of the entire video signal so that one of these brightness levels matches the reference brightness level. Then, the white balance adjustment circuit 10R,
The light quantities of red, green and blue images from the cathode ray tubes 1R, 1G and 1B are individually adjusted by 10G and 10B.

Each of the brightness levels of the projection lens pupil images 5R, 5G, 5B extracted from the frame memory 17 through the above adjustments corresponds to the projection lens pupil images 5R, 5R stored in the storage device 15.
Continue until each of the reference brightness levels of G and 5B is met. When this adjustment is completed, the projection display device 18 reproduces the brightness and white balance at the initial setting.

The example in which the pattern generator 6 outputs a white raster image signal having 100% luminance to perform white balance adjustment has been described above. However, a low luminance white raster signal of about 15% is used to obtain a low luminance signal. You can also adjust the white balance. It is also possible to provide a gamma correction circuit or the like on any part of the path from the signal processing circuit 9 to the cathode ray tubes 1R, 1G, and 1B to adjust the white balance at the intermediate brightness level.

As described above, in this embodiment, the brightness and white balance are automatically adjusted in the projection display device 18, and no external adjustment is required.

Generally, in a projection display device, the luminance level decreases with the passage of time due to deterioration of the cathode-ray tube, etc. Therefore, if the highest luminance level possible in the projection display device is set at the time of initial setting, readjustment is performed again. Sometimes it becomes impossible to reproduce this initial brightness level. A second embodiment of the projection display apparatus according to the present invention which solves this problem will be described below. The configuration of the projection display device in this case is the same as that in FIG.

FIG. 3 is a characteristic diagram showing an example of changes in the luminance of the projection display apparatus over time. The luminance level of the projection display apparatus when time is displayed on the horizontal axis and 100% white raster image is displayed on the vertical axis. Are taken respectively.

Generally, in a projection display device, as shown in FIG. 3, assuming that the brightness in the initial state is a, the brightness gradually decreases due to deterioration of the cathode ray tube over time, and T1 time The brightness becomes a ′ later, and the brightness further decreases as time passes.

For such a decrease in brightness, the brightness can be increased by increasing the cathode current of the cathode ray tube, but the cathode current is limited. Therefore, in the second embodiment, in order to adjust such a decrease in brightness, the cathode current is set to be lower than the limit value in advance during the initial adjustment.

FIG. 4 is a diagram showing the cathode current necessary to maintain the projection display apparatus at a constant brightness in this manner. The horizontal axis represents time and the vertical axis represents the cathode current. The maximum allowable value of cathode current is used.

In FIG. 4, in order to maintain the brightness during installation adjustment, the cathode current is increased and the brightness cannot be adjusted at time T2 when the required maximum allowable value b is reached. Therefore, the cathode current limit value is set to b, the limit value is set to b ′ which is smaller than b during the initial adjustment, and the cathode current is increased at each adjustment, and the brightness adjustment is continued until the cathode current reaches the limit value b.

When the cathode current is adjusted in this way, as shown in FIG. 5, the brightness is constant from the initial adjustment, and the deterioration of the cathode ray tube depends on the product of the cathode current and time. The time until the replacement is increased from T1 to T2, and the brightness a ′ can be maintained after the time T1 and after the time T2. Since the brightness a'cannot be maintained after the time T2 elapses, the CRT is replaced or used with the brightness lowered.

In the second embodiment, the brightness in the initial adjustment state of the projection display device is maintained and the life of the cathode ray tube is extended. It should be noted that means for adjusting the brightness from outside the projection display device is provided so that the user can perform the initial setting of the brightness after the factory shipment, and the information from the video camera 4 at that time is set as described above. It may be stored in the storage device 15 and automatically adjusted to the initially set brightness.

When the cathode current reaches the maximum allowable value b, the brightness control can no longer be performed. FIG. 6 is a block diagram showing a third embodiment of the projection type display device according to the present invention, which is provided with a display means for displaying the fact.
Reference numeral 1 is a display means, and the portions corresponding to those in FIG.

In FIG. 6, cathode ray tubes 1R, 1G, 1
When the brightness level of the projection lens pupil image does not reach the reference brightness level stored in the storage device 15 even if the cathode current of B is set to the maximum allowable value b, the control circuit 16 informs the display means 21 to that effect. Display information. As a result, the user can easily know that the brightness level can no longer be automatically adjusted, and can take measures such as replacement of the cathode ray tube.

As the display means 21, for example, L
ED or other suitable display means can be used,
In addition, an image signal such as a mark indicating that, for example,
Input from the signal processing circuit 8 etc., and the transmissive screen 3
It may be displayed above.

This embodiment is also effective for a projection display device that does not adjust the brightness level or white balance.

FIG. 7 is a block diagram showing the essential parts of a fourth embodiment of the projection display apparatus according to the present invention, in which 22 is a liquid crystal projector, 23 is a light source, 24 and 25 are dichroic mirrors, and 26 to 29 are. Mirror, 30R, 30G,
Reference numeral 30B is a transmissive liquid crystal panel for red, green, and blue images, 31, 32 are dichroic mirrors, 33 is a projection lens, and 34 is a projection lens pupil image of the projection lens 33 due to reflection of the transmissive screen 3. The same reference numerals are given to the portions corresponding to, and redundant description will be omitted.

The fourth embodiment is a three-panel liquid crystal projector in which each color image is obtained by a liquid crystal panel.

In FIG. 7, the liquid crystal projector 22 uses liquid crystal panels 30R, 30G and 30B, and the light source 2
White light emitted from the dichroic mirror 24,
25 is split into red, green, and blue color lights respectively, red light is reflected by mirrors 26, 27 and reflected on a liquid crystal panel 30R for red images, and blue light is reflected by mirrors 28, 29 on a liquid crystal panel 30B for blue images. And the green light is directly applied to the liquid crystal panel 30G of the green image.

These liquid crystal panels 30R, 30G, 30B
1 are respectively supplied with the color signals R, G, B processed by the signal processing circuit 8, the brightness adjusting circuit 9, and the white balance adjusting circuits 10R, 10G, 10B shown in FIG. 1, and the red color is displayed on the liquid crystal panel 30R. The component image, the green component image is displayed on the liquid crystal panel 30G, and the blue component image is displayed on the liquid crystal panel 30B. Therefore, in the liquid crystal panel 30R, the red light from the mirror 27 is modulated and transmitted by the image of the red component, in the liquid crystal panel 30B, the blue light from the mirror 29 is modulated and transmitted by the image of the blue component, and in the liquid crystal panel 30G. The green light from the dichroic mirrors 24 and 25 is modulated by the image of the green component and transmitted. The image light transmitted through the liquid crystal panels 30R, 30G and 30B is reflected or transmitted through the dichroic mirrors 31 and 32 to be combined, and a color image is obtained, and the projection lens 33
Is enlarged and projected on the transmissive screen 3.

In such a configuration, as in the first embodiment shown in FIG. 1, a white image is displayed on the transmissive screen 3 and the video image is picked up by the video camera 4, whereby the projection lens 33 has a projection lens. Each color component of the pupil image 34 is obtained, and white balance and brightness are automatically adjusted.

In this embodiment, the projection lens pupil image 3
4 is one white image, but by using a color video camera as the video camera 4, the light of the white image can be easily split into red, green, and blue lights, and the respective brightness levels can be extracted. You can

As described above, according to this embodiment, the white balance and the brightness of the liquid crystal projector device can be automatically adjusted, and the display means 21 is provided as in the third embodiment shown in FIG. By providing the light source 23, it is possible to notify the user of the replacement time of the light source 23.

FIG. 8 is a constitutional view showing a fifth embodiment of the projection display apparatus according to the present invention, in which reference numeral 35 is a photoelectric conversion element, and the portions corresponding to those in FIG. The description is omitted. In the following, unless otherwise specified, the three cathode ray tubes 1R, 1G, and 1B are collectively referred to as the cathode ray tube 1, and similarly, the projection lens pupil image 5R,
The projection lens pupil image 5 and the white balance adjustment circuits 10R, 10G, and 10B are also collectively referred to as the white balance adjustment circuit 10.

In FIG. 8, in this embodiment, a photoelectric conversion element 35 such as a color sensor is used in place of the video camera 4 in the first embodiment shown in FIG. The projection lens pupil image 5 on the screen 3 is detected.

The photoelectric conversion element 35 is provided on the optical path of the reflected light from the transmissive screen 3, and the red, green, and blue reflected light of the projection lens pupil image 5 due to the regular reflection of the transmissive screen 3 is photoelectrically converted. The signals are detected by the element 35, converted into corresponding voltage signals, converted into digital data by the A / D converter 14, and supplied to the storage device 15 and the control circuit 16.

Here, the red, green, and
The reference luminance level of the blue digital data is output from the A / D converter 14, and the adjustment of the luminance and white balance is performed with the red, green, and blue digital data output from the A / D converter 14. The operation is performed by comparing with the reference luminance level stored in the storage device 15, and other operations are the same as those in the first embodiment shown in FIG.

Therefore, in this embodiment, the frame memory 17 of the first embodiment shown in FIG. 1 is not necessary, and the brightness level of the projection lens pupil image 5 is extracted from the frame memory 17 accordingly. This eliminates the need for work, reduces the circuit scale, and enables cost reduction.

In this embodiment, the projection lens pupil image 5
Although the photoelectric conversion element 35 is used as the detection means, a photoelectric conversion element and a lens may be used instead, and the same effect can be obtained. In this case, the photoelectric conversion element 35 outputs the integrated values of the brightness levels of red, green, and blue of the projection lens pupil image, and the A / D converter 14 converts the integrated values of the brightness levels into digital data. To be done. The brightness and white balance is adjusted by digital data of the integrated values of red, green and blue output from the A / D converter 14 and the storage device 15.
Of the same reference luminance level data is compared.

When the photoelectric conversion element and the lens are used as described above, the circuit scale and the like can be reduced and the cost can be reduced as described above, and the transmissive screen can be used as compared with the case where only the photoelectric conversion element is used. It is possible to collect a large amount of reflected light from the light source 3, and thus it is possible to adjust the brightness and white balance with higher accuracy.

FIG. 9 is a block diagram showing the essential parts of a sixth embodiment of the projection display apparatus according to the present invention.
R, 36G, and 36B are photoelectric conversion elements for detecting red light, green light, and blue light, respectively, and parts corresponding to those in the above drawings are designated by the same reference numerals and redundant description will be omitted.

In the embodiment shown in FIG. 8, one photoelectric conversion element 35 is used, but in this sixth embodiment, as shown in FIG. 9, three photoelectric conversion elements 36R for detecting different color lights are used. ，
36G and 36B are used, and although not shown, an A / D converter that digitizes the output signal is provided for each of the photoelectric conversion elements 36R, 36G, and 36B. The other structure is similar to that of the fifth embodiment shown in FIG.

In FIG. 9, photoelectric conversion elements 36R and 36R are provided.
G and 36B are arranged at positions where reflected light from the same position on the transmissive screen 3 is detected.
6R detects the amount of specularly reflected light of the projection lens pupil on the transmissive screen 3 of the cathode ray tube 1R that emits red image light, and the photoelectric conversion element 36G emits green image light on the transmissive screen 3 of the cathode ray tube 1G. The amount of specular reflection light of the projection lens pupil is detected, and the photoelectric conversion element 36B detects the amount of specular reflection light of the projection lens pupil on the transmissive screen 3 of the cathode ray tube 1B that emits red image light.

In the sixth embodiment, since the reflected light from the projection lens pupil is at the same position on the transmissive screen 3, it is assumed that the image displayed on the transmissive screen 3 has uneven brightness and uneven color. Is not affected by the positional deviation of the reflected light of each projection lens pupil.

Therefore, for example, by disposing a reference surface light source or the like at the position of the transmissive screen 3 and storing the output levels of the photoelectric conversion elements 36R, 36G, and 36B at that time in the storage device 15 as reference luminance levels, Can be set,
This reference brightness level enables the initial adjustment of the projection display device.

Although the photoelectric conversion elements 36R, 36G and 36B are used in the sixth embodiment, it is obvious that the photoelectric conversion elements 36R, 36G and 36B may be combined with a lens. is there.

Further, in this embodiment, in addition to the adjustment of the brightness and the white balance, the unevenness of the brightness and the unevenness of the color are corrected as the uniformity of the screen of the transmissive screen 3.
Image quality can be improved.

FIG. 10 is a constitutional view showing a seventh embodiment of the projection type display apparatus according to the present invention which is capable of correcting the unevenness in brightness and the unevenness in color, and 5a, 5b, 5c and 5d.
Is a projection lens pupil image, 14a, 14b, 14c and 14d are A / D converters, 15a, 15b, 15c and 15d are storage devices, and 35a, 35b, 35c and 35d are image pickup elements (photoelectric conversion elements may be used), 37 Is a brightness unevenness / color unevenness correction circuit, 38 is an LUT (look-up table), and 39 is L
This is a PF (low-pass filter), and the portions corresponding to those in the above drawings are denoted by the same reference numerals and redundant description will be omitted.

In the figure, the luminance unevenness / color unevenness correction circuit 37 is composed of, for example, an LUT 38 and an LPF 39 provided for each cathode ray tube of each color image. The projection lens pupil images 5a, 5b, 5c, 5d are image pickup devices 35a, 35
Observed at b, 35c, and 35d, respectively. Image sensor 35
Output signals of a, 35b, 35c and 35d are converted into digital data by A / D converters 14a, 14b, 14c and 14d, respectively, and projected lens pupil images 5a, 5b, 5c and 5d.
Storage device 15 as the brightness levels of the red, green, and blue components of
a, 15b, 15c, 15d.

FIG. 11A shows a projection display device 1
8B shows an example of the luminance in the horizontal direction of the screen of FIG.
Also shows an example of the brightness of each color.

In the projection type display device 18, FIG.
As shown in FIG. 11A, generally, the central part is bright and the peripheral part is dark, and since three CRTs of red, green, and blue are arranged in a horizontal row, FIG. As shown in FIG. 3, for example, a color shift occurs in which the blue light amount is strong on the left side of the screen and the red light amount is strong on the right side, resulting in uneven brightness and uneven color on the screen.

As a method of correcting these, for example, the screen is divided into several areas and a plurality of LUTs for correction are used.
A method is known in which each area is corrected using the data. Such initial adjustment of unevenness in brightness and unevenness in color is performed visually from the image light emission side of the transmissive screen 3 or by using the video camera 4, as in the case of adjusting the above-mentioned brightness and white balance. To do. When the states of the uneven brightness and the uneven color change from the time of the initial adjustment, readjustment becomes necessary.

Hereinafter, the correction of the unevenness in brightness and the unevenness in color in the seventh embodiment will be described. The initial setting method and the method for detecting the brightness levels of red, green and blue of each projection lens pupil image are shown in FIG.
Since it is the same as the embodiment shown in FIG. 8 and FIG.

In FIG. 10, as in the previous embodiment, the output of the pattern generating means 6 is used to display a white image on the transmissive screen 3, and the image pickup devices 35a, 35b, 35 are displayed.
The output signals of c and 35d are converted into A / D converters 14a and 14b,
The brightness levels of the red, green, and blue components of the projection lens pupil images 5a, 5b, 5c, 5d obtained by digitizing 14c, 14d and the red, green, blue stored in the storage devices 15a, 15b, 15c, 15d. The control circuit 16 compares the reference brightness level of the component. When there is uneven brightness or uneven color,
One of all these comparisons is inconsistent,
LUT for control circuit 16 that does not match
The data of 38 are updated in the same direction. In this way, uneven brightness and uneven color are corrected.

The image pickup devices 35a, 35b, 35c,
A photoelectric conversion element may be used instead of 35d, and
These photoelectric conversion elements are composed of three photoelectric conversion elements that detect red, green, and blue light, respectively. By arranging the photoelectric conversion elements as shown in FIG. 9, the initial setting and the same operation as described in FIG. 9 are performed. You can also make initial adjustments.

FIG. 12 is a block diagram showing a first embodiment of a multi-display device according to the present invention using a plurality of the projection type display devices described above.
b, 11c, 11d are input terminals, 18a, 18b, 18
c and 18d are the projection display device described above, 4
Reference numeral 0 is an input terminal for a video signal, and 41 is an expansion distributor.

In this embodiment, four projection display devices are used, but any number may be combined.

In FIG. 12, the projection display devices 18a, 18b, 18c and 18d are arranged vertically and horizontally in two columns to form one multi-display device. Here, the projection display device 18a is arranged in the upper left portion, the projection display device 18b is arranged in the upper right portion, the projection display device 18c is arranged in the lower left portion, and the projection display device 18d is arranged in the lower right portion. To do.

The video signal input from the input terminal 40 is supplied to the enlargement distributor 41 so that the video signal represented by the video signal is divided into four parts, ie, an upper left part, an upper right part, a lower left part and a lower right part. , Divided, the upper left part is input terminal 1
1a to the projection display device 18a, the upper right part from the input terminal 11b to the projection display device 18b,
The lower left portion is supplied from the input terminal 11c to the projection display device 18c, and the lower right portion is supplied from the input terminal 11d to the projection display device 18d. As a result, these projection display devices 18a, 18b, 18c, 1
The image of the image signal from the input terminal 40 is enlarged and displayed on one entire screen including four transmissive screens of 8d.

The brightness and white balance of such a multi-display device are determined by the projection display device 18
After assembling and installing the a, 18b, 18c, and 18d, they are initially adjusted so as to coincide with each other. This initial adjustment may be done manually while visually checking,
It may be performed by capturing the transmitted image light of the entire screen of the multi-display device with a video camera.

Then, the state at the time of this initial adjustment is set to the initial state, and the transmission of each projection type display device 18a, 18b, 18c, 18d imaged by the video camera at this time is made the same as in the embodiment shown in FIG. The projection display devices 18a, 18b, 1 have the brightness level of the projection lens pupil image reflected on the mold screen as the reference brightness level.
The data is stored in the storage device for each of 8c and 18d.

In the subsequent readjustment, for each projection display device 18a, 18b, 18c, 18d, the reference brightness level and the brightness level of the projection lens pupil image reflected on the transmissive screen imaged by the video camera at the time of readjustment are set. Is calculated and the control circuit controls the white balance adjusting circuit and the brightness adjusting circuit to adjust the brightness and white balance to the same state as the initial state. Therefore, there is no variation in color or brightness among the projection display devices 18a, 18b, 18c, 18d, and a uniform and high-quality image can be obtained.

The adjustment of the brightness and the color is complicated and takes a very long time to adjust in the conventional multi-display device using a plurality of projection display devices. When the display device is used, the brightness and color can be adjusted with high accuracy in a short time.

Needless to say, even if the liquid crystal projector device shown in FIG. 7 is combined to form the multi-display device shown in FIG. 12, the white balance and brightness can be automatically adjusted with high precision and in a short time. .

In this embodiment, a video camera is used for explanation, but a combination of a color sensor or a photoelectric conversion element and a lens may be used, and the arrangement of each photoelectric conversion element is shown in FIG. As shown, the initial setting and initial adjustment may be performed.

Further, the display means 21 may be provided as in the embodiment shown in FIG. 6 to notify the user of the replacement time of the cathode ray tube or the liquid crystal panel.

FIG. 13 is a block diagram showing a second embodiment of a multi-display device according to the present invention provided with such display means, in which 42a, 42b, 42c and 42d are output terminals, 43 and 44 are communication means. Reference numeral 45 is a display means, and the parts corresponding to those in FIG.

In the figure, the projection display device 1
8a, 18b, 18c, and 18d, the information indicating the replacement time of the cathode ray tube or the liquid crystal panel obtained by the control circuit described above is supplied to the communication means 43 from the output terminals 42a, 42b, 42c, and 42d, respectively. Is transmitted to the communication means 44 at a place distant from and is supplied to the display means 45. The communication means 43, 44 are connected, for example, via a telephone line or the like.

From the above structure, for example, the communication means 4
4 and the display means 45 are arranged at a distributor or a manufacturer so that the customer's projection display device 18
The seller, manufacturer, etc. can easily know the deterioration condition of the CRT of a, 18b, 18c, 18d and the replacement time of the CRT, and the service can be provided by notifying the non-specialist user of this time accurately. Useful for etc.

This applies not only to the multi-display device but also to the display device composed of one projection display device described above.

FIG. 14 is a block diagram showing an eighth embodiment of the projection display apparatus according to the present invention, in which 46 is a switch, 47 is subtraction means, and 48 is a frame memory.
The parts corresponding to those in the above drawings are designated by the same reference numerals and duplicate description will be omitted.

In this embodiment, the influence of external light is removed to detect the luminance more accurately than in the above-described embodiments, and improve the precision of adjusting the luminance and white balance.

In the figure, similar to the embodiment shown in FIG. 1, initial setting and readjustment are performed, but before that, the brightness level of outside light is detected. Therefore, the control circuit 16 switches the switch 46 to the frame memory 48 side. At this time, the cathode ray tubes 1R, 1G, and 1B are set in a state in which no image light is projected, and the video camera 4 images the transmissive screen 3 on which no image is displayed. The output signal of the video camera 4 is converted into digital data by the A / D converter 14 and stored in the frame memory 48 via the switch 46. This digital data is data representing the brightness level of the external light with which the transmissive screen 3 is irradiated.

Next, the control circuit 16 switches the switch 46 to the subtracting means 47 side. At this time, the control circuit 16 switches the switch 7 to the side of the pattern generating means 6 to display a white image on the transmissive screen 3 by the white raster signal from the pattern generating means 6 as in the previous embodiment. The video camera 4 captures the white image. Video camera 4
Output signal is converted into digital data by the A / D converter 14 and is supplied to the subtracting means 47 via the switch 46 to subtract the digital data stored in the frame memory 48. The output data of the subtracting means 47 is stored in the frame memory 17. Therefore, the digital data stored in the frame memory 17 is the brightness level data from which the brightness level of the external light is removed.

When the above operation is completed, the control circuit 16 detects the brightness levels of the red, green and blue components of the projection lens pupil image from the digital data of the frame memory 17, and stores them in the storage device 15 as the reference brightness level. The initial setting is performed to prepare for subsequent readjustment.

When the brightness and white balance are to be readjusted thereafter, the cathode ray tubes 1R, 1G and 1B are not operated and the brightness level data of the external light is taken into the frame memory 48 as described above, and this data is stored. make use of,
The subtracting means 47 corrects the luminance level of the external light included in the data from the video camera 4 for capturing the white image displayed on the transmissive screen 3, and supplies it to the frame memory 17.

As described above, in this embodiment, the external light component can be removed and the brightness level of the projection lens pupil image can be detected with higher accuracy, so that the accuracy of adjusting the brightness and the white balance can be improved. improves. Further, since it is not affected by external light when adjusting the projection display device, it is not restricted by the installation position or the adjustment time zone.

FIG. 15 is a block diagram showing the ninth embodiment of the projection display apparatus according to the present invention, in which 49 is a storage device, and the portions corresponding to those in FIG. Is omitted.

Also in this embodiment, the influence of external light can be eliminated.

In FIG. 15, cathode ray tubes 1R, 1G,
The video camera 4 captures an image of the transmissive screen 3 while 1B is not projecting the image light on the transmissive screen 3.
Detects the brightness level of external light. The output signal of the video camera 4 is converted into digital data by the A / D converter 14 and then stored in the frame memory 17. The control circuit 16 extracts or calculates the brightness level of external light at the position of the projection lens pupil image from the brightness data of the frame memory 17 at this time, and stores it in the storage device 49.

Then, the initial setting operation is performed. That is,
The control circuit 16 switches the switch 7 to the side of the pattern generating means 6 to display a white image on the transmissive screen 3 by the white raster signal from the pattern generating means 6 as in the previous embodiment. The video camera 4 captures the white image. The output signal of the video camera 4 is converted into digital data by the A / D converter 14 and stored in the frame memory 17. The control circuit 16 extracts or calculates the brightness level of the projection lens pupil image from the digital data of the frame memory 17, subtracts the brightness level of the external light stored in the storage device 49 from the result, and stores the subtraction result. It is stored in the device 15.

When the brightness and white balance are readjusted, the brightness level of the external light is detected again as described above, and the storage device 4
9 is stored. Next, the data of the white image on the transmissive screen 3 is stored in the frame memory 17, the control circuit 16 extracts or calculates the brightness level of the projection lens pupil image from the data, and the result is stored in the storage device 49. The brightness level of the external light is subtracted, and the subtraction result is compared with the reference brightness level stored in the storage device 15 to adjust the brightness level and the white balance.

In this embodiment, the same effect as that of the embodiment shown in FIG. 14 is obtained, a storage device 49 having a capacity smaller than that of the frame memory 48 shown in FIG. 14 is used, and the switch 46 shown in FIG. Because it is unnecessary,
The circuit scale and cost can be further reduced.

Note that in the embodiment shown in FIGS. 14 and 15, instead of the video camera 4, another image pickup device or a photoelectric conversion means such as a photodiode or a color sensor can be used.

The configuration, the adjustment of the brightness level and the white balance, the brightness detection method, and the like have been mainly described above regarding the embodiments of the projection display apparatus and the multi-display apparatus according to the present invention. An embodiment of the projection display device according to the present invention, which is effective as a presentation system used for displaying images at conferences and presentations, will be described.

FIG. 16 is a block diagram showing one of such embodiments, in which 50 is a computer, 51 is an image processing circuit,
52 is an interface circuit (hereinafter referred to as I / F),
Reference numeral 53 is a light emission pointing device such as a laser pointer, and 54 is a transmitted light of a spot light.

Here, the brightness and white balance adjusting means and the brightness detecting means described in the previous embodiment are omitted.

In the figure, the video signal output from the computer 50 is supplied from the input terminal 11 to the projection display device 18, and the video of this video signal is displayed on the transmissive screen 3. When the transmissive screen 3 is irradiated with spot light from the image light emission side by the light emission indicating device 53 such as a laser pointer, the spot light passes through the transmissive screen 3 and the transmitted light 54 of the spot light is generated at the image light incident side. To be observed. The video camera 4 images the entire surface of the transmissive screen 3, and the output signal of the video camera 4 is digitized by the A / D converter 14 and supplied to the image processing circuit 51. In this image processing circuit 51,
The brightness of the transmitted light 54 of the spot light or the position on the transparent screen 3 is detected from the output data of the A / D converter 14, and the detection result is converted into an appropriate signal as an input signal of the computer 50 by the I / F 52. Computer 50
Is supplied to.

Next, the operation of this embodiment will be described in detail.

The computer 50 supplies a video signal to the projection display device 18 as a signal source. In the projection display device 18, the supplied video signal is processed by the signal processing circuit 8, the brightness adjusting circuit 9 and the like and supplied to the cathode ray tube 1. As a result, the image based on the image signal from the computer 50 is enlarged and projected on the transmissive screen 3.

The viewer is observing the displayed image on the image light emission side of the transmissive screen 3, and irradiates a spot light from the light emission instructing device 53 to a desired position in the image. At this time, the video camera 4 is capturing an image of the entire transmissive screen 3, and the output signal of the video camera 4 is supplied to the image processing circuit 51. Image processing circuit 51
Then, the transmitted light 5 of the spot light appearing on the image light incident side of the transmissive screen 3 from the output signal of the video camera 4 is transmitted.
4 is detected, its position is recognized, and its coordinate data and the like are sent to the computer 50 via the I / F 52. The I / F 52 is connected to, for example, the mouse interface of the computer 50, and the supplied coordinate data is supplied to the computer 50 as indicating the position designated by the mouse. That is, the spot light of the light emission indicating device 53 functions as a mouse.

Here, for example, the light emission instructing device 53 can selectively output the spot light in two steps, for example, the spot light of the low brightness level and the spot light of the high brightness level, and outputs the spot light of the low brightness level. In this case, when the mouse is clicked, the state is the same as when the mouse is not clicked, and when the spot light of high brightness level is output, the state is the same as when the mouse is clicked. Further, in the image processing circuit 51,
The brightness level of the transmitted light 54 of the spot light is detected to identify whether the spot light is in the high brightness level or the low brightness level, and the above coordinate data is computerized for the spot light of the high brightness level. I will send it to 50.

In such an embodiment, when adjusting the brightness and white balance, a switch (not shown) is switched to adjust the output of the A / D converter 14 as in the above-described embodiment. You can use it.

As described above, in this embodiment, when a viewer gives a presentation, for example, the light emission indicating device 53 can be used instead of the mouse, and the computer 50 can be easily operated during the presentation.

The computer 50 may be, for example, a personal computer or a workstation, or a word processor.

Further, the light emission instructing device 53 can not only switch the spot light between the two brightness levels but can also identify the visible light and the infrared light or the red light and the blue light by the image processing circuit 51. It may be a combination of lights. Furthermore, a shadow of a hand or the like is used instead of the light emission indicating device 53,
The shape of the shadow may be identified.

FIG. 17 is a block diagram showing another embodiment effective as a presentation system and the like, and 55 is a synthesizing circuit. The parts corresponding to those in FIG. .

In the figure, the synthesizing circuit 55 synthesizes the video signal output from the signal processing circuit 8 and the output signal of the image processing circuit 51, and supplies it to the luminance adjusting circuit 9 as one video signal. Here, the image processing circuit 51 accumulates the position data of the transmitted light 54 of the spot light of the light emission instructing device 53 detected from the output data of the A / D converter 14, and represents the locus of the transmitted light 54 from these position data. A video signal is formed and supplied to the synthesizing circuit 55, whereby the trajectory of the transmitted light 54 is displayed on the transmissive screen 3.

In this way, in this embodiment, the light emission instructing device 53 can overwrite an arbitrary image on the image displayed on the transmissive screen 3 with the spot light of the light emission instructing device 53.

[0123]

As described above, according to the present invention,
Even if the white balance or brightness changes from the initial adjustment state such as when shipped from the factory due to changes over time, the white balance and brightness will be automatically reproduced to the same as the initial adjustment state. Is automatic, so it can be performed quickly and accurately.

Further, according to the present invention, even if a multi-display device is formed by combining a plurality of projection display devices, the brightness and white balance in the initial adjustment can be kept constant. It is possible to obtain high-quality images without variations in the brightness and color of each projection display.

[Brief description of drawings]

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

FIG. 2 is a diagram showing a configuration example of a transmissive screen in FIG.

FIG. 3 is a diagram showing an example of changes over time in the brightness level of the projection display apparatus.

FIG. 4 is a characteristic diagram showing temporal adjustment of cathode current in the second embodiment of the projection display apparatus according to the present invention.

5 is a diagram showing a characteristic of a luminance level with respect to a change in cathode current shown in FIG.

FIG. 6 is a configuration diagram showing a third embodiment of the projection display device according to the present invention.

FIG. 7 is a configuration diagram showing a fourth embodiment of the projection display device according to the present invention.

FIG. 8 is a configuration diagram showing a fifth embodiment of the projection display device according to the present invention.

FIG. 9 is a configuration diagram showing a main part of a sixth embodiment of the projection display apparatus according to the present invention.

FIG. 10 is a seventh projection display device according to the present invention.
It is a block diagram which shows the Example of.

FIG. 11 is a diagram showing an example of characteristics of luminance unevenness and color unevenness on the screen of the projection display apparatus.

FIG. 12 is a configuration diagram showing an embodiment of a multi-display device according to the present invention.

FIG. 13 is a configuration diagram showing another embodiment of the multi-display device according to the present invention.

FIG. 14 is an eighth projection display device according to the present invention.
It is a block diagram which shows the Example of.

FIG. 15 is a ninth projection display device according to the present invention.
It is a block diagram which shows the Example of.

FIG. 16 is a configuration diagram showing a tenth embodiment of a projection display device according to the present invention, which is effective as a presentation system.

FIG. 17 is a configuration diagram showing an eleventh embodiment of a projection display device according to the present invention which is effective as a presentation system.

FIG. 18 is a diagram showing a basic configuration of a rear projection display device.

[Explanation of symbols]

 1, 1R, 1G, 1B CRT 2, 2R, 2G, 2B Projection lens 3 Transmissive screen 4 Video camera 5, 5R, 5G, 5B, 5a to 5d Projection lens pupil image 6 Pattern generation means 7 Switch 8 Signal processing circuit 9 Brightness adjusting circuit 10, 10R, 10G, 10B White balance adjusting circuit 11, 11a to 11d Video signal input terminal 12 Drive adjusting circuit 13 Cutoff adjusting circuit 14 A / D converter 15, 15a to 15d Storage device 16 Control circuit 17 Frame memory 18, 18a to 18d Projection display device 19 Fresnel lens 20 Lenticular lens 21 Display means 22 Liquid crystal projector 23 Light source 24, 25 Dichroic mirror 26 to 29 Mirror 30R, 30G, 30B Liquid crystal panel 31, 32 Dichroic mirror 33 Projection lens 34 Projection lens Pupil image 35, 35a to 35d Photoelectric conversion element 36R, 36G, 36B Photoelectric conversion element 37 Luminance unevenness correction circuit 38 LUT 39 LPF 40 Video signal input terminal 41 Enlargement distributor 43, 44 Communication means 45 Display means 46 switch 47 subtraction means 48 frame memory 49 storage device 50 computer 51 image processing circuit 53 light emission indicator 54 spot light of light emission indicator 55 combining means

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Gozo Sato, 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa, Ltd. Hitachi, Ltd. multimedia system development headquarters (72) Inventor Komei Yoshida, Totsuka-ku, Yokohama-shi, Kanagawa 292, Machi, Hitachi Ltd., Multimedia Systems Development Headquarters (72) Inventor Ryuichi Someya, 292, Yoshida-cho, Totsuka-ku, Yokohama, Kanagawa Prefecture, Hitachi, Ltd. Multimedia Systems Development HQ (72) Inventor, Fumio Haruna Kanagawa 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Ltd. Hitachi, Ltd. multimedia system development headquarters

Claims (8)

[Claims] 1. A projection display device comprising: a transmissive screen that reflects a part of irradiation light; and a projection unit that projects image light onto the transmissive screen by using a projection lens. Adjusting means for adjusting at least one of balance and brightness, control means for controlling the adjusting means, pattern generating means for displaying an image pattern for adjustment on the projection screen, and image for adjusting A first for detecting a pupil image of the projection lens specularly reflected by the transmissive screen when a pattern is displayed
And the brightness levels or brightness ratios of the red, green and blue components of the pupil image of the projection lens detected by the first detection means are compared with the initially set reference brightness level or reference brightness ratio. A projection display device, comprising: a comparison calculation means, wherein the control means controls the adjustment means using a comparison calculation result of the comparison calculation means. 2. The first storage unit according to claim 1, further comprising a first storage unit, wherein the image pattern for adjustment is detected by the first detection unit when it is displayed on the transmissive screen during initial setting. The brightness levels or brightness ratios of the red, green, and blue components of the pupil image of the projection lens are stored in the storage means as the reference brightness levels or reference brightness ratios, and at the time of readjustment, the comparison calculation means causes the comparison image to be adjusted. The brightness levels or brightness ratios of the red, green, and blue components of the pupil image of the projection lens detected by the first detection means when the pattern is displayed on the transmissive screen are stored in the storage means. A projection display apparatus, characterized in that a reference brightness level or a reference brightness ratio is compared and calculated, and the control means controls the adjusting means in accordance with a comparison calculation result of the comparison calculation means. 3. The plurality of second detection means for detecting pupil images of the projection lens in different areas on the transmissive screen according to claim 1 or 2, and the adjustment image pattern is the transmissive image pattern. A plurality of second storage means in which the brightness level or the brightness ratio of the pupil image of the projection lens detected by each of the second detection means when displayed on the screen is previously stored as a reference brightness level or a reference brightness ratio. And a correction unit for correcting unevenness in brightness or color on the transmissive screen, the comparison calculation unit performing the second detection when the image pattern for adjustment is displayed on the transmissive screen. And comparing the brightness level or brightness ratio of the pupil image of the projection lens detected by each of the means with the reference brightness level or reference brightness ratio corresponding to each stored in the second storage means. Projection display device in which the control means according to the comparison result and controlling said correcting means. 4. The projector according to claim 1, 2 or 3, wherein the projection means emits image light of red, green and blue respectively and projects the image light onto the transmissive screen, and the first detection means includes red and green. , Three photoelectric conversion elements for detecting the amount of blue light, each of the photoelectric conversion elements being red, green, and blue generated on the image light incident side of the transmissive screen on which the image pattern for adjustment is displayed. A projection display device characterized by detecting the brightness level at the same position of the pupil image of the projection lens. 5. The first device according to claim 1, 2, 3 or 4, wherein the projection means does not emit image light.
Third storage means for storing the output brightness level of the detection means, and the third storage means based on the output brightness level of the first detection means when the image pattern for adjustment is displayed on the transmissive screen. Means for subtracting the brightness level stored in the means, and the red, green, and
Detect the standard brightness level or standard brightness ratio of the blue component,
A projection display device, wherein the comparison calculation means performs comparison calculation with the reference luminance level or the reference luminance ratio. 6. The cathode ray tube and the projection lens according to claim 1, 2, 3, 4 or 5, wherein the cathode current is adjusted to compensate for a decrease in luminance due to deterioration of performance of the cathode ray tube over time. When the compensation by adjusting the cathode current is at a limit, information indicating that is displayed on the display means, the projection display device. 7. A multi-display device comprising a plurality of projection display devices according to claim 1, 2, 3, 4, 5 or 6. 8. A multi-display system using a plurality of projection display devices according to claim 1, 2, 3, 4 or 5, wherein said projection means comprises a cathode ray tube and said projection lens. For each of the projection display devices, means for generating information indicating that luminance deterioration due to deterioration of performance over time is compensated by adjusting the cathode current, and compensation for luminance deterioration by adjusting the cathode current is limited. A multi-display system characterized in that a communication means for communicating the information from each of the projection display devices is provided and the information sent from the communication means is displayed on the display means.