JPH08251614A - Video projector - Google Patents

Abstract

PURPOSE: To provide a video projector capable of executing stable correction even when the correction and correction value of each projection unit are increased by independently controlling a color luminance correcting circuit arranged in each projection unit by a respectively different correction value. CONSTITUTION: Signals for correcting color irregularity and luminance irregularity are generated from a correction signal generating circuit GN and the correction signals are superposed to video signals supplied to respective projection tubes P1 to P6 in respective projection units 2A, 2B to correct the color and luminance irregularity of the video signals. A control part 17 independently controls the correction values of respective circuits 1A, 1B so as to differentiate the correction values. Thereby the color and luminance irregularity can be corrected in each of plural projection units 2A, 2B, and even when the correction values are increased, stable correction can be attained without insisting on excess load to the projection tubes.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video projector which forms a multi-screen by combining a plurality of projection units.

[0002]

2. Description of the Related Art Conventionally, a video projector that constitutes a multi-screen is used by combining a plurality of projection units to form one large screen and enlarging and displaying an image on the screen. Different images can be displayed on.

FIG. 3 shows a multi-screen constructed by combining nine such conventional projection units D1 to D9. When multiple projection units are combined to form a single screen, the image of each projection unit may have uneven brightness.
There is uneven color, and if it is displayed as it is, the image quality deteriorates. That is, the uneven brightness has a characteristic that the projection lens arranged in each projection tube darkens the periphery of the screen with respect to the center of the screen, and as shown by the diagonal lines in FIG. 3, the brightness of the periphery of the screen by each projection unit decreases. It can be seen that the connection between the projection units is poor and the image quality is significantly degraded.
As for color unevenness, red, green, and
Since the projection tubes for projecting the lights of the three primary colors of blue and the respective projection lenses are juxtaposed in the horizontal direction with respect to the screen, the projection distances on the left and right of the screen are different, and the hues on the left and right of the screen are observed differently. It In a multi-screen in which a plurality of projection units are combined, the difference in color becomes more noticeable at the boundary between the screens.

For this reason, when displaying an image on a multi-screen, R which is a video signal of the three primary colors of each projection unit.
It is required to correct unevenness in color and unevenness in luminance for (red), G (green), and B (blue) signals before projection. Conventionally, for uneven brightness, R, G, and B signals are superimposed with parabolic waves synchronized with horizontal and vertical synchronizing signals to correct a decrease in brightness at the peripheral portion of the screen of each projection unit. The sawtooth wave synchronized with the horizontal synchronizing signal is superimposed on the B signal to correct the color unevenness on the left and right of the screen.

A method of such correction will be described with reference to FIG. FIG. 4A is an example of R, G, and B input video signals before correction, and the upper end of the signal has a flat shape in the 1H period. 4B-4D show corrected R, G,
Each video signal of B is shown. The R signal shown in FIG. 4B is
The parabolic wave is superposed and the sawtooth wave is superposed to form a waveform having an upward slope. The G signal shown in FIG. 4C has a waveform in which only the parabolic wave is superimposed and the central portion is curved and lowered, and the B signal shown in FIG. 4D is superposed with the parabolic wave and the sawtooth wave, and goes up to the left. The waveform has a slope of.

That is, the uneven brightness on the left and right of the screen is corrected by the parabolic wave component superimposed on the R, G, B signals, and R, B
The uneven color is corrected by the sawtooth wave component superimposed on the. For the G signal, since the G projection tube is arranged in the center, correction of color unevenness is unnecessary, and the sawtooth wave is not superimposed.

Further, as shown in FIG. 4E, it is possible to correct uneven brightness in the upper and lower parts of the screen by superimposing a parabola wave having a vertical period (1 V) on each of the R, G and B video signals. .

When the nine screens are formed as shown in FIG. 3 described above, each screen is displayed by a video projector having three projection tubes of red, green and blue as one unit. The same correction as above is required for the six projection tube type video projector.

FIG. 5 is a block diagram of a color / luminance correction circuit using such a conventional six projection tubes. In FIG. 5, video signals of three primary colors of R, G, and B are input from input terminals T1, T2, and T3, and after being corrected by the color / luminance correction circuit 1, the first projection unit 2A and the second projection unit 2A Is output to the projection unit 2B. The correction signal output to the first projection unit 2A is amplified by the R, G, and B video output circuits 3, 4, and 5, and an image is projected from the projection tubes P1, P2, and P3, and similarly. The correction signal output to the second projection unit 2B is amplified by the video output circuits 6, 7, and 8 for R, G, and B, and an image is projected from the projection tubes P4, P5, and P6.

The correction signal generating circuit GN is a circuit for generating a signal for correcting color unevenness and brightness unevenness, and has a sawtooth wave (Hs) and a parabola wave (Hp) having a horizontal period and a parabola wave (Vp) having a vertical period. Respectively. Based on these input waveform signals, the correction signal generation circuit GN determines the sawtooth wave component signal (color correction signal) for color unevenness correction and the parabola for brightness unevenness correction described with reference to FIG. The signal of the wave component (luminance correction signal) is output and supplied to the input terminals T4 and T5 of the color / luminance correction circuit 1.

The color / brightness correction circuit 1 has a color unevenness correction signal (sawtooth wave) synchronized with a horizontal synchronization signal input from an input terminal T4 and a brightness unevenness synchronized with a horizontal and vertical synchronization signal input from an input terminal T5. Correction signal (parabolic wave)
After being added by the adders 12 and 13, R and B are output as color / luminance correction signals and input from input terminals T1 and T3.
The G signal input from the input terminal T2 is added to the signal by the adders 9 and 11, and only the luminance unevenness correction signal is added by the adder 10 to obtain a video signal whose color unevenness and luminance unevenness are corrected. It is output to the first projection unit 2A and the second projection unit 2B. The reason why only the luminance unevenness correction signal is added to the G signal is that the projection tubes P2 and P5 for the G signal are respectively arranged at the center of each unit and the distances to the left and right of the screen are almost equal and it is not necessary to correct the color unevenness. Is. The polarity of the R signal is inverted by the inverting circuit IV and input to the adder 12.

That is, for the R signal input from the input terminal T1, the polarity of the color unevenness correction signal input from the input terminal T4 is inverted by the inverting circuit IV, and the brightness unevenness correction signal input from the input terminal T5. And the color / luminance unevenness correction signal added by the adder 12 are added by the adder 9
Correct brightness unevenness. Here, the polarity of the color unevenness correction signal added to the R signal is inverted by the projection tubes P1 and P3 of the first projection unit 2A and the projection tubes P4 and P6 of the second projection unit 2B, respectively. This is because the tubes P2 and P5 are symmetrically arranged.

As for the B signal inputted from the input terminal T3, the color unevenness correction signal inputted from the input terminal T4 and the luminance unevenness correction signal inputted from the input terminal T5 are added by the adder 13 The uneven brightness correction signal is added by the adder 11 to correct the uneven color and brightness.

In this way, with respect to the uneven brightness, the uneven brightness correction signal synchronized with the horizontal and vertical synchronizing signals is superimposed on each of the video signals R, G and B to correct the decrease in the brightness in the peripheral portion of each screen to obtain the color. Regarding the unevenness, a color unevenness correction signal synchronized with the horizontal synchronizing signal is superimposed on the R and B signals to correct the color unevenness on the left and right of the screen.

[0015]

However, in the color / brightness correction circuit used in the above-described conventional video projector, if the correction amount is increased in order to improve the correction of the color / brightness unevenness, the video signal processing circuit There was a drawback that the screen became unnatural beyond the dynamic range. Further, increasing the correction amount causes an excessive correction signal to be supplied to the projection tube, which causes a problem that the focus of the projection tube deteriorates and the image quality deteriorates. Further, since the same correction signal is applied to each projection unit from one color / brightness correction circuit, it is not possible to satisfactorily correct the color / brightness unevenness for each projection unit. Therefore, in view of the above problems, the present invention can correct color unevenness and brightness unevenness for each of a plurality of projection units, and can perform stable correction without imposing an excessive burden on the projection tube even if the correction amount is increased. The purpose is to provide a projector.

[0016]

According to a first aspect of the present invention, there is provided a video projector having first and second projection units, each projection unit projecting red, green and blue light, respectively. In a video projector including the projection tube of, the video output means for supplying the video signals of red, green, and blue to the projection tubes of the first and second projection units, respectively, A correction signal generating unit that generates a signal for correcting color unevenness and brightness unevenness and a correction signal generating unit that is arranged for the first projection unit and superimposes the correction signal from the correction signal generating unit on the video signal of each projection tube A first correction means for correcting the brightness and a second correction unit arranged for the second projection unit for superposing the correction signal from the correction signal generating means on the video signal of each projection tube to correct the color and brightness. The second correction means, the first and the second Correction means constituted by a control means for controlling at and different correction amounts each independently a correction of the color and brightness due.

According to a second aspect of the present invention, in the video projector according to the first aspect, the first and second correction means enable the ratio of the correction signal to each video signal to be changed by the control means. One of the outputs of the second correction means is configured to increase the ratio of the video signal, and the other output is configured to increase the ratio of the correction signal.

According to a third aspect of the present invention, in the video projector according to the first or second aspect, each of the first and second correction means inputs the color nonuniformity correction signal and outputs it with an arbitrary amplitude. And a second multiplier, a third multiplier for inputting the luminance nonuniformity correction signal and outputting it at an arbitrary amplitude, and a first multiplier
And the output of the second multiplier is added to the first and second video signals of the red, green and blue video signals, and the output of the third multiplier is added to each of the red, green and blue video signals. And adding means for adding.

According to a fourth aspect of the present invention, in the video projector according to the first aspect, the control means controls the color / brightness correction amount applied to the first correction means and the second correction means. It is configured to switch between the color / brightness correction amounts that have been applied to each other.

According to a fifth aspect of the present invention, in the video projector according to the fourth aspect, the control means issues an instruction signal for executing switching of the correction amounts of the first and second correction means at a predetermined cycle. It is provided with a time setting means to be generated.

[0021]

In the invention according to claim 1, a signal for correcting color unevenness and brightness unevenness is generated from the correction signal generating means, and this correction signal is provided for each of the first and second projection units. The second correction means superimposes and corrects the video signal supplied to each projection tube of each projection unit. The controller independently controls the correction amounts of the first and second correction means, and controls the correction amounts of the respective correction means to be different from each other, so that each image of the first and second projection units is controlled. The corrected video signal can be output to the output means.

In the invention according to claim 2, the control means can change the ratio of each video signal and the correction signal input to the first and second correction means, and the first or second correction One of the outputs of the means can be controlled to increase the ratio of the video signal and the other output can be controlled to increase the ratio of the correction signal.

In the invention according to claim 3, the first and second correcting means are respectively constituted by the first to third multipliers and the adding means, and the color unevenness correction signal is constituted by the first and second multipliers. Is input and output with an arbitrary amplitude, and the luminance unevenness correction signal is input with the third multiplier and output with an arbitrary amplitude. Also,
The respective addition means add the outputs of the first and second multipliers to the first and second video signals of the red, green and blue video signals, and the output of the third multiplier is red. , Green, and blue video signals are added.

In the invention according to claim 4, the control means includes the correction amount of the color / luminance unevenness applied to the first correction means and the correction amount of the color / luminance unevenness applied to the second correction means. And can be controlled by switching.

In the invention according to claim 5, the control means may be provided with a time setting means for outputting an instruction signal for switching the correction amounts of the first and second correction means, and the control means may be switched at a predetermined cycle.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the video projector of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention. FIG. 2 shows FIG.
FIG. 7 is a waveform diagram of a luminance nonuniformity correction signal showing a change in the luminance nonuniformity correction amount in the example of FIG. The same or similar reference numerals are given to the portions corresponding to those of the conventional example in FIG.

In FIG. 1, the first or second color / luminance correction circuit 1A or 1B inputs the video signals R, G and B of the three primary colors from the input terminals T1 to T3 and the correction signal generation circuit GN to the input terminal. The color unevenness correction signal of the sawtooth wave synchronized with the horizontal synchronization signal is input via T4, and the input terminal T5
The point that the unevenness correction signal of the parabolic wave synchronized with the horizontal and vertical synchronization signals is input via the same as that of the conventional example shown in FIG.

The first color / luminance correction circuit 1A includes R and B
Adders 9 and 1 for adding a color / brightness unevenness correction signal obtained by adding a color unevenness correction signal and a brightness unevenness correction signal to the signal, respectively.
1. Adders 12 and 13 for adding a color unevenness correction signal and a brightness unevenness correction signal to output a color / brightness unevenness correction signal, an adder 10 for adding only a brightness unevenness correction signal to a G signal, and a control described later. The first and second multipliers 14 and 15 for outputting the color unevenness correction signal having the amplitude corresponding to the control signal of the unit 17 are provided, and the brightness unevenness correction signal having the amplitude corresponding to the control signal of the control unit 17 is output. The third multiplier 16 is provided. The output ends of the first and second multipliers 14 and 15 are connected to one input side of the adders 12 and 13 for inputting the color unevenness correction signal, and the output end of the third multiplier 16 is an adder. 1
It is connected to the other input side for inputting the luminance nonuniformity correction signals of 0, 12, and 13. The G signal is directly input to one input side of the adder 10 from the input terminal T2. Further, the color shading correction signals output from the first and second multipliers 14 and 15 are arranged because the projection tubes P1 and P3 of the projection unit 2A are arranged symmetrically with respect to the green projection tube P2. Output with opposite polarity.

The first and second multipliers 14 and 15 include:
A color nonuniformity correction signal is input from the correction signal generation circuit GN via an input terminal T4, and a control signal for controlling the amplitude of the color nonuniformity correction signal to a required level is input from a control unit 17 (described later). Further, the unevenness correction signal is input to the third multiplier 16 from the correction signal generation circuit GN through the input terminal T5, and the amplitude of the uneven brightness correction signal output from the control unit 17 is set to a required level. A control signal for controlling is input.

The first projection unit 2A amplifies and outputs the corrected R, G, B signals output from the adders 9, 10, 11 of the first color / luminance correction circuit 1A. Circuits 3, 4, 5 and projection tubes P1, P2, P for projecting red, green and blue respectively connected to these video output circuits.
3 has the same configuration as the conventional one.

The second color / luminance correction circuit 1B also has a first
The color / luminance correction circuit 1A has the same configuration. That is, the color / brightness correction circuit 1B adds the color / brightness unevenness correction signal obtained by adding the color unevenness correction signal and the brightness unevenness correction signal to the R and B signals, and adds the color unevenness correction signal and the brightness unevenness correction signal. Adders 21 and 22 for adding a signal to output a color / brightness unevenness correction signal, an adder 19 for adding only a brightness unevenness correction signal to the G signal, and a color unevenness having an amplitude corresponding to a control signal of the control unit 17. First and second output correction signals
And a third multiplier 25 that outputs a luminance unevenness correction signal having an amplitude according to the control signal of the control unit 17. The output terminals of the first and second multipliers 23 and 24 are connected to one input side of the adders 21 and 22 for inputting the color unevenness correction signal, and the third multiplier 25
The output terminal of is connected to the other input side of the adders 19, 21 and 22 for inputting the uneven brightness correction signal. The G signal is directly input to one input side of the adder 19 from the input terminal T2. Further, the color shading correction signals output from the first and second multipliers 23 and 24 are arranged symmetrically about the green projection tube P5 with the projection tubes P4 and P6 of the projection unit 2B being arranged symmetrically. The reverse polarity is also the same as in the first color / luminance correction circuit 1A.

Further, the first and second multipliers 23 and 2
A color nonuniformity correction signal is input to the reference numeral 4 from the correction signal generation circuit GN via the input terminal T4, and a control signal for controlling the amplitude of the color nonuniformity correction signal from the control unit 17 to a required level is input. . The multiplier 25 receives a brightness unevenness correction signal from the correction signal generation circuit GN via the input terminal T5, and a control signal for controlling the amplitude of the brightness unevenness correction signal to a required level from the control unit 17. Is entered.

Then, the second projection unit 2B is also
Video output circuits 6, 7, and 8 for amplifying the corrected R, G, and B signals output from the adders 18, 19, and 20 of the brightness correction circuit 1B, and red connected to these video output circuits, respectively. , Green, and blue projection tubes P4, P5, and P6 are configured in the same manner as the conventional one.

The above-mentioned control section 17 is composed of, for example, a CPU, and each multiplier 1 of the first color / luminance correction circuit 1A.
A DC voltage for controlling the amplitudes of the color nonuniformity correction signal and the brightness nonuniformity correction signal is sent to Nos. 4, 15 and 16 as the first control signal. Similarly, the control unit 17 sends a DC voltage for controlling the amplitude to each of the multipliers 23, 24, 25 of the second color / luminance correction circuit 1B as a second control signal. That is, according to the control signal of the control unit 17, the first and second colors
The correction amount of the brightness correction circuit can be changed. Also,
The first and second control signals are independent of the first and second control signals, respectively.
It is a control signal that can control the correction signals of the color / luminance correction circuits 1A and 1B. Further, the control amounts by the first and second control signals are set such that one is large and the other is small, and the control unit 17 can switch each control signal output to each color / luminance correction circuit 1A or 1B. . That is,
The control unit 17 can individually control the correction of the color / brightness unevenness of the first and second color / brightness correction circuits 1A and 1B, and also can control one of the color / brightness correction circuits 1A and 1B. Can be replaced with the control signal of the other color / luminance correction circuit 1B or 1A.

Reference numeral 26 is a time limit circuit as a time setting means composed of, for example, a counter or a timer, and outputs an instruction signal for exchanging the control signals to the control section 17 at predetermined time intervals. The time limit circuit 26 includes the control unit 17
If the control unit 17 is arranged outside the device or the control unit 17 is configured by a CPU, a built-in counter or timer can be used. Alternatively, each time the power switch (not shown) is turned on, the control signal of the first color / brightness correction circuit 1A and the control signal of the second / brightness correction circuit 1B of the control unit 17 may be switched. Good.

Next, the operation of the embodiment having the above construction will be described. Basic operations of the first and second color / luminance correction circuits 1A and 1B and the first and second projection units 2A and 2B. Are the same, the first color / luminance correction circuit and the first
The operation of the A projection unit 2A will be described.

The R, G and B signals which are the video signals of the three primary colors are input to the respective input terminals of the adders 9, 10 and 11 of the color / luminance correction circuit 1A via the input terminals T1, T2 and T3. To be done. On the other hand, from the correction signal generation circuit GN to the input terminal T
The color nonuniformity correction signal input via 4 is input to the multipliers 14 and 15, and is output as a color nonuniformity correction signal of a required amplitude by the control signal from the control unit 17, and one input of the adders 12 and 13 is input. Entered on the edge. On the other hand, the brightness nonuniformity correction signal input from the correction signal generation circuit GN via the input terminal T5 is input to the multiplier 16 and is output with a required amplitude by the control signal from the control unit 17, and the adders 10 and 1 are connected.
Each of 2 and 13 is input to the other input terminal.

Therefore, the R signal and the color / luminance unevenness correction signal output from the adder 12 are added by the adder 9,
The corrected R signal is amplified by the video output circuit 3 of the first projection unit 1A and a red image is projected from the projection tube P1. Further, the B signal and the color / brightness unevenness correction signal output from the adder 13 are added by the adder 11, the corrected B signal is amplified by the video output circuit 5, and a blue image is projected from the projection tube P3. It

On the other hand, G input through the input terminal T2
As for the signal, since the projection tube P2 corresponding to the G signal is arranged in the center and the distances to the left and right of the screen are almost the same as in the conventional case, it is not necessary to correct the color unevenness. Therefore, the control unit 1
By the control of 7, only the brightness unevenness correction signal of the required amplitude output from the multiplier 16 is added to the G signal by the adder 10,
The corrected G signal is amplified by the video output circuit 5,
A green image is projected from the projection tube P2.

When a predetermined time has passed,
An instruction signal for instructing switching of the control signal is output from the time limit circuit 26 to the control unit 17, and the control unit 17 can switch and output the control signal for the first and second color / luminance correction circuits 1A and 1B. it can. That is, for example, the control signal of the first color / brightness correction circuit 1A having a large correction amount is output to the second color / brightness correction circuit 1B having a small correction amount, and the second color / brightness correction circuit 1B having a small correction amount is output. Is output to the first color / luminance correction circuit 1A having a large correction amount. Therefore, the projection tubes P1 to P1 of the respective projection units 2A and 2B are
Deterioration due to burning of the phosphors of P3 and P4 to P6 is reduced, and stable correction can be maintained for a long period of time.

Next, referring to FIG. 2, a change in the brightness correction amount when the control unit 17 individually controls the first color / brightness correction circuit 1A and the second color / brightness correction circuit 1B will be described. The luminance unevenness correction signal will be described. It is assumed that the G signal shown in FIG. 2A is input to both correction circuits from the input terminal T2. When the brightness unevenness correction amount of the first color / brightness correction circuit 1A is reduced, as shown in FIG. 2B, the correction signal waveform of the adder 10 has an amplitude M corresponding to the vicinity of the central portion of the screen and a peripheral portion of the screen. The corresponding difference in amplitude S is reduced. At this time,
When the brightness unevenness correction amount of the second color / brightness correction circuit 1B is increased, the correction signal waveform of the adder 19 corresponds to the amplitude M near the center of the screen and the periphery of the screen as shown in FIG. 2C. The difference in the amplitude S becomes large, and the signal component in the peripheral portion becomes extremely large as compared with the signal component in the central portion. In addition,
Although only the G signal has been described in FIG. 2, the same correction is made for the R and B signals.

Therefore, by individually controlling the brightness of the first and second color / brightness correction circuits 1A and 1B in this manner, the output signal of one color / brightness correction circuit 1A or 1B is mainly used as a video signal. It can be used as an output, and the output signal of the other color / luminance correction circuit 1B or 1A can be mainly output as a correction signal. This makes it possible to increase the correction amount without widening the dynamic range of the video signal processing circuit as compared with the conventional correction, and without giving the excessive correction signal as in the conventional case to deteriorate the focus of the projection tube. And good correction is possible.

Further, since the control unit 17 can individually control the correction amounts of the respective color / luminance correction circuits 1A and 1B,
Depending on the content of the image or the environment in which it is used, it is also possible to switch between and display an image in which the amount of color / brightness unevenness correction is increased and a bright screen in which the amount of correction is suppressed and the overall brightness is increased.

Further, in the first and second color / brightness correction circuits 1A and 1B of this example, the respective image signals and the color unevenness correction signal and the brightness unevenness correction signal are added to the adders 9 to 13 and 1, respectively.
Although 8 to 22 are used for addition, a multiplier may be used instead of these adders for modulation with the correction signal.

In the above embodiment, the case where six projection tubes are used for one projection unit has been described, but it is needless to say that the same effect can be obtained when nine projection tubes are used. Nor.

[0046]

As described above, the first to third aspects of the present invention are described.
According to the video projector described in 3, the color / luminance correction circuit is provided for each projection unit so that they can be controlled independently and with different correction amounts. Therefore, as in the conventional case, the video signal processing including the correction circuit is performed. The advantage of being able to correct color unevenness and brightness unevenness of an image by increasing the correction amount without increasing the circuit dynamic range and without adding excessive correction signals to each projection tube to deteriorate focus. There is.

Further, according to the present invention as set forth in claim 4, since the correction amount between the projection units can be switched, an image in which the correction amount is increased and color and brightness unevenness are appropriately corrected, and the correction amount. It is possible to switch between an image in which the total brightness is reduced and the overall brightness is increased according to the content of the video or the usage environment.

Further, according to the invention of claim 5,
The correction amount of each projection tube in each projection unit is automatically switched at fixed time intervals, and correction can be applied without biasing to one of the projection tubes, so deterioration due to burn-in of the phosphor of each projection tube can be prevented. However, there is an advantage that stable correction can be maintained for a long period of time.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of a video projector of the present invention.

FIG. 2 is a waveform diagram of a brightness correction signal showing a change in the brightness correction amount in the embodiment of FIG.

FIG. 3 is a diagram showing a display state of each screen peripheral portion of a multi-screen using a plurality of conventional projection units.

FIG. 4 is a waveform diagram showing an example of a color / luminance correction signal.

[FIG. 5] Color of a conventional 6-projection tube type video projector
It is a block diagram of a brightness correction circuit.

[Explanation of symbols]

1A, 1B First and second color / luminance correction circuits (correction means) 2A, 2B First and second projection units 3-8 Video output circuits (image output means) 9-13, 18-22 Adder ( Adder means 14-16, 23-25 Multiplier 17 Control section (control means) 26 Time circuit (time setting means) GN Correction signal generation circuit (correction signal generation means) P1 to P6 Projection tubes R, G, B 3 primary colors Video signal

Claims (5)

[Claims] 1. A video projector having first and second projection units, each projection unit including three projection tubes projecting red, green, and blue light, respectively. Red on each projection tube of the second projection unit,
Image output means for supplying green and blue image signals, correction signal generation means for generating signals for correcting color unevenness and brightness unevenness of light projected from each of the projection units, and for the first projection unit First correction means for superimposing the correction signal from the correction signal generating means on the video signal of each projection tube to correct the color / luminance, and the second projection unit. Second correction means for superposing the correction signal from the correction signal generation means on the video signal of each projection tube to correct the color / luminance, and correction of the color / luminance by the first and second correction means. A video projector, comprising: a control unit for controlling each of them independently and with different correction amounts. 2. The first and second correction means enable the ratio of the correction signal to each of the video signals to be changed by the control means, and one of the outputs of the first or second correction means 2. The video projector according to claim 1, wherein the ratio of the video signal is increased, and the other of the outputs is increased in the ratio of the correction signal. 3. Each of the first and second correction means comprises:
First and second multipliers that input a color nonuniformity correction signal and output it at an arbitrary amplitude, third multipliers that input a color nonuniformity correction signal and output at an arbitrary amplitude, and the first and second The output of the second multiplier is added to the first and second video signals of the red, green and blue video signals, and the output of the third multiplier is added to the red, green and blue video signals. The video projector according to claim 1 or 2, further comprising: an adding unit that adds to the video projector. 4. The control unit controls the color / luminance correction amount applied to the first correction unit and the color / luminance correction amount applied to the second correction unit. 2. The video projector according to claim 1, wherein the switch and the switch are switched to each other. 5. The control means comprises time setting means for generating an instruction signal for executing switching of the correction amounts of the first and second correction means at a predetermined cycle. The video projector according to claim 4.