JPH01291588A - Color slippage correction circuit for projection type display - Google Patents

Abstract

PURPOSE:To perform color slippage correction with a few amount of power consumption by coupling a transformer coupling means so as to permit currents with reverse polarity with each other to at least two deflecting coils as correction currents. CONSTITUTION:An amplifier 3 supplies a vertical deflecting current to vertical deflecting coils 4, 5, and 6. Here, parallel resistors 8, 9, and 10 are set at values of around ten or more times the parasitic resistances of the vertical deflecting coils 4, 5, and 6, respectively, and also, at the same values with each other. Meanwhile, a multiplier 12 performs the multiplication of an inputted saw-tooth wave signal 1 of 1V and saw-tooth wave signal 2 of 1H, and generates a color slippage correction signal, and the color slippage correction signal is inputted to an amplifier 14 via a filter 13 to compensate the frequency characteristic of a succeeding part. The amplifier 14 supplies the correction current to the primary side of a transformer 11, and also, the transformer 11 supplies the correction current supplied to the primary side from the secondary side to the vertical deflecting coils 5 and 6.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a color shift correction circuit for a projection display.

[Conventional technology]

In a projection display, three projection tubes for red, green, and blue are generally arranged horizontally together with a projection lens to project and synthesize a color image onto a single screen.

FIG. 10 is an explanatory diagram showing the relationship between a projection lens and an image projected onto a screen in a general projection display.

In FIG. 10, 100 is a projection lens, 110 is a screen, and ω is the difference between blue light and green light.

As shown in Figure 10, when projecting and combining color images, the red and blue images are projected diagonally to the screen, so based on projection geometry, vertical keystone distortion (
A trapezoidal distortion with two vertical sides having different lengths occurs, which results in color blurring.

In order to correct this color shift, for example, Japanese Patent Laid-Open No. 62-9
As described in Japanese Patent No. 2595, a deflection yoke (hereinafter referred to as D
It is abbreviated as Y. ), similar to the convergence yoke (hereinafter abbreviated as CY) for electron beam auxiliary deflection.
is mounted on the neck of the projection tube, and the output from the convergence amplifier is applied to its CY to correct color shift.

The main cause of color shift caused by such a projection optical system (projection lens, etc.) is the vertical trapezoid (hereinafter abbreviated as V-KS).
l It is an abbreviation of Keystone. ) In addition to distortion,
Horizontal linearity (hereinafter abbreviated as H-L[N.) I-L IN is Horizontal Li
It is an abbreviation for narity. ) Distortion etc.

FIG. 11 shows the positional relationship between the projection tube and DY, CY in a boat-type projection display.

In FIG. 11, 16 is a projection tube, and 17 is a DY.

18 is cy, 19 is an electron gun.

DY17. The deflection sensitivity of CYlB can be expressed as the deflection distance of the electron beam with respect to a unit of electromagnetic energy, and is proportional to the effective magnetic path length (in the length direction of the neck portion) of each yoke.

On the other hand, the effective magnetic path length of CYIB is as shown in Figure 11.
It is about 1/2 of that of DY17.

The reason for this is the dimensional restriction to prevent the adverse effect of CYlB on the electron lens portion of the electron gun 19 adjacent to the left side of CYlB.

Therefore, the deflection sensitivity of CYlB is about 1/2 worse than that of DY17.

[Problem to be solved by the invention]

As mentioned above, the deflection sensitivity of CY is about 1/2 worse than that of DY, and in conventional technology, color shift correction is performed using CY with such poor deflection sensitivity. There is a problem in that a large amount of power is consumed for this purpose.

The purpose of the present invention is to solve the problems of the prior art described above,
An object of the present invention is to provide a color shift correction circuit that can perform color shift correction with low power consumption.

[Means to solve the problem]

In order to achieve the above object, the present invention includes a color shift correction circuit that includes a color shift correction signal generation means for generating and outputting a color shift correction signal, and a color shift correction signal from the primary color shift correction signal generation means. an amplifying means for amplifying and outputting the amplifying means; an output signal from the amplifying means is input; and among the plurality of deflection coils,
transformer coupling means for flowing a correction current corresponding to the output signal through at least two deflection coils; in particular, the transformer coupling means causes currents of opposite polarity to flow through at least two deflection coils as the correction current; I made it so that it is combined so that it flows.

[Effect]

-a, if you try to flow current from two different power sources into one load, the current from one power source will also flow into the other power source, and the power consumption in both power sources will decrease. However, in the present invention, as described above, the transformer coupling means is configured to couple at least two deflection coils so as to flow currents of opposite polarity as correction currents, so that the deflection The correction current does not flow into the deflection current supply means that supplies the deflection current to the coil. Further, since the deflection current supply means causes the deflection current to flow in the same phase to the deflection coil, the negative deflection current does not flow into the amplification means via the transformer coupling means. Therefore, power consumption in the deflection current supply means and the amplification means does not increase.

Furthermore, according to the present invention, the DY deflection coil, which has a deflection sensitivity that is about twice as good as that of the CY deflection coil, can correct the color shift between the three primary colors caused by the projection optical system. The power consumed for correction can be reduced by almost half compared to conventional methods.

〔Example〕

FIG. 1 shows a first embodiment of the present invention. This embodiment is a color shift correction circuit for correcting the V-KS distortion described above.

In Figure 1, 1 is an IV (one vertical scanning period) sawtooth wave signal, 2 is an IH (one horizontal scanning period) sawtooth wave signal, 3 is a negative feedback amplifier for vertical deflection, and 4, 5, and 6 are green, respectively. (G) Vertical deflection coil of deflection yoke (DY) for emergency use, red (R) color, blue (B) emergency use, 7 is deflection current detection resistor for negative feedback, 8° 9.10 is for green and red, respectively. , DY parallel resistor for blue (in particular, 9.10 is for differential application of color shift correction signal), 11 is a transformer, 12 is a multiplier, 13 is a filter, 14 is a negative feedback amplifier for color shift correction , 15 is a correction current detection resistor, and 20 is an output signal of the multiplier 12.

Next, the operation of this embodiment will be explained.

The 1-inch sawtooth signal l input to the amplifier 3 and the multiplier 12 and the IH sawtooth signal manually input to the multiplier 12 are well-known signals generated and used in conventional general projection displays. belongs to.

Amplifier 3 transmits vertical deflection current to vertical deflection coil 4°5.6
At the same time, a negative feedback operation is performed so that the waveform of the vertical deflection current detected by the detection resistor 7 becomes similar to the waveform of the input sawtooth wave signal 1. Here, the parallel resistances 8, 9.10 are the vertical deflection coils 4, 5, respectively.
．． The values are set to be approximately 10 times or more than the parasitic resistance of No. 6 and equal to each other.

On the other hand, the multiplier 12 multiplies the manually input sawtooth wave signal 1 by the IH sawtooth signal 2 to generate a color shift correction signal. Here, the frequency component of this color shift correction signal consists of a high frequency horizontal scanning period component and its sidebands. Next, this color shift correction signal is sent to an amplifier 14 via a filter 13 for compensating the frequency characteristics of the subsequent section.
is input.

The amplifier 14 supplies the correction current to the primary side (first side) of the transformer 11.
At the same time, negative feedback is performed so that the waveform of the correction current detected by the detection resistor 15 becomes similar to the waveform of the color shift correction signal inputted from the filter 13.

The transformer 11 also transfers the correction current supplied to the primary side from the secondary side (the upper side in FIG. 1) to the vertical deflection filter 5.
6.

Here, since the vertical deflection current supplied from the amplifier 3 flows through the vertical deflection coils 4 and 5.6 in the same phase, no current flows through the primary side of the transformer 11, and therefore no current flows into the amplifier 14. Don't flush.

On the other hand, since the correction current supplied from the amplifier 14 via the transformer 11 flows through the vertical deflection coils 5 and 6 in opposite phases, no current flows to the amplifier 3.

That is, there is independence between amplifiers 13 and 14.

Orthogonality is maintained (that is, there is no signal leakage).

Generally, if you try to flow current from two different power sources into one load, the current from one power source will also flow into the other power source, increasing the power consumption of both power sources. However, in this embodiment, as described above, the vertical deflection current supplied from amplifier 3 is
4 and the correction current supplied from amplifier 14 also does not flow into amplifier 3.
There is no increase in power consumption.

Furthermore, according to this embodiment, color shift correction can be performed using the DY vertical deflection coil, which has a deflection sensitivity that is approximately twice as superior as that of CY, so that the power consumed for color shift correction can be reduced compared to conventional methods. can be reduced to almost half.

Now, as a final explanation of this embodiment, the configuration of the filter 13 will be briefly described.

A correction current flowing from the amplifier 14 to the primary side (lower side in FIG. 1) of the transformer 11 is set to 1. If the correction currents flowing through the vertical deflection coils 5 and 6 due to this are Is and L, then
The following formula holds true.

Here, p = jω (complex angular frequency) M = mutual inductance L2 of transformer 11 = secondary inductance R of transformer 11, = resistance value L of parallel resistors 9 and 10, = vertical deflection coil 4, 5.6 The inductance of the equation (■) above is transformed into τ p ...... ■ The second term on the right side of the above equation (■), that is, 1/(1+1
/τp) means frequency characteristics.

FIG. 2 is a circuit diagram showing an example of the filter 13 shown in FIG. 1.

In FIG. 2, 82 and 83 are resistors, 84 are capacitors, and 85 is an operational amplifier.

The above frequency characteristics can be obtained by constructing the filter 13 in FIG. 1 using an operational amplifier 85 as shown in FIG.
2.83 resistance value respectively R1゜R2, capacitor 8
When the capacitance value of 4 is C2, R,=R,,Rz ct
Compensation is achieved by selecting the time constant so that = τ.

Now, in the case of a vertical scanning frequency of 607, actual constant examples are shown below. In addition, Ro is vertical deflection coil 4, 5.6
The resistance value of the parasitic resistance R3 is the resistance value of the detection resistor 15.

LD = 2mH, Ro = 4Ω, Ro = 100Ω.

Lz = 5 mH, M = 500 uH, 'R+ = Rz
=1 kΩ, Cz=120nF.

R1=5Ω This completes the explanation of the first embodiment of the present invention, and next, the second embodiment of the present invention is shown in FIG.

In FIG. 3, the same components as in FIG. 1 are given the same reference numerals. In addition, 2'' is a signal obtained by differentiating the IH sawtooth signal 2 shown in FIG. 1, 21 is a filter, 22.23 is a prinidad resistor for voltage detection, and 24 is a DC blocking capacitor.

In the embodiment shown in FIG. 1 described above, the amplifier 14 performs a negative feedback operation so that the waveform of its output current (i.e., correction current) becomes similar to the waveform of the input color shift correction signal, which is a so-called current feedback method. In contrast, in this embodiment, the amplifier 14 performs a negative feedback operation so that the waveform of its output voltage (i.e., correction voltage) becomes similar to the waveform of the input color shift correction signal. It uses a so-called voltage feedback method.

That is, in this embodiment, the operation of the amplifier 14 is as follows.
While applying a correction voltage to the primary side of the transformer 11,
A negative feedback operation is performed so that the waveform of the correction voltage detected by the bleeder resistors 22 and 23 becomes similar to the waveform of the color shift correction signal inputted from the filter 21.

Furthermore, in this embodiment, if the output voltage (ie, correction voltage) of the amplifier 14 is El, then the correction current IS+I6 flowing through the vertical deflection coil 5.6 due to this is expressed by the following equation.

・・・・・・■ Here, n=) Turns ratio of lance 11 L=) Equivalent inductance looking into lance 11 from the primary side, which is equal to Lo/(2n”) C= of capacitor 24 The first term of the numerator on the right side of the capacitance value 2〇 above, that is, n /
p L o is the integral factor of the inductance of the vertical deflection coil, which is expressed by the multiplier 12 as shown in FIG.
By setting one of the input signals to the pulsed signal 2° obtained by differentiating the IH sawtooth signal 1 shown in Fig. 1,
be compensated.

On the other hand, the second term of the right-hand denominator in equation ■, that is, 1/P''
LC is f"(D 4M wo1 horizontal scanning layer"A(L
If it is chosen sufficiently larger than H), it can be ignored.

Also, the second term of the numerator on the right side in formula (■), that is, 1/(1
+R, /PL) has a different time constant value, but the above formula ■
It is the same as the second term on the right side of , that is, 1/(1+1/τp). Therefore, compensation can be achieved by providing the filter 21 with the same configuration as that shown in FIG.

Note that other operations in this embodiment are the same as those in the embodiment shown in FIG. 1, so a description thereof will be omitted.

Therefore, in this embodiment as well, the same effects as in the embodiment shown in FIG. 1 described above can be obtained.

This completes the explanation of the embodiment shown in FIG.

Next, as a third embodiment of the present invention, the above-mentioned H-LI
A color shift correction circuit that corrects N distortion will be explained.

FIG. 4 shows a third embodiment of the invention.

In FIG. 4, 25 is a horizontal drive pulse, 26 is a horizontal output transistor, 27 is a damper diode, 2 is a resonant capacitor, 29, 30, and 31 are DY horizontal deflection coils for green, red, and blue colors, respectively. 32 is a power supply choke coil, 33 is a DC blocking bypass capacitor, 34 is a deflection current detection resistor, 35 is a multiplier, 36 is a maximum value detector, 37 is a changeover switch, 38 is a negative feedback amplifier,
39 is a transformer, and 40 is a correction current detection resistor. Note that the components other than 35 to 40 belong to well-known horizontal deflection output circuit technology.

Further, FIG. 5 is a waveform diagram showing signal waveforms of main parts in FIG. 4.

In FIG. 5, a, b, c, and d respectively indicate signal waveforms with the same symbols in FIG. 4, and BL is a horizontal retrace period.

Now, the operation of this embodiment will be explained.

Horizontal output transistor 26 receives horizontal drive pulse 25
and accordingly, O in the latter part of the horizontal scanning period.
It becomes N state. Further, the resonance capacitor ff128 resonates with the inductance component of the horizontal deflection coils 29, 30, 31 during the horizontal retrace period, and generates a flyback pulse as shown in FIG. .31
A sawtooth wave horizontal deflection current flows.

Therefore, this horizontal deflection current is detected by the detection resistor 34, and
A sawtooth signal as shown in FIG. 5 is obtained, and the multiplier 35
Enter. The multiplier 35 squares the input sawtooth signal and outputs a parabolic signal as shown in FIG.

The maximum value detector 36 is composed of, for example, a diode and a capacitor, detects the maximum value of the input parabolic signal, and inputs it to the other input of the changeover switch 37 .

The switching of the changeover switch 37 is controlled by the input pulsed signal 2'' shown in FIG.
Turn the switch to the α side only during the horizontal retrace period, and turn the switch to the β side during other periods.

Therefore, as an output, a signal having a waveform as shown by the solid line in FIG. 5d is obtained. The signal output from the changeover switch 37 is input to the amplifier 38 as a color shift correction signal.

The amplifier 38 supplies the correction current to the primary side (fourth side) of the transformer 39.
At the same time, a negative feedback operation is performed so that the waveform of the correction current detected by the detection resistor 40 becomes similar to the waveform of the color shift correction signal inputted from the changeover switch 37.

Here, the reason why a signal whose horizontal retrace period portion is flattened, as shown by the solid line in FIG. 5d, is used as the color shift correction signal is as follows.

That is, if a signal showing a steep waveform change, such as the one shown in FIG. Current will be input. However, since the transformer 39 is an inductive load,
This is because when a current exhibiting such a steep waveform change is input, an excessive voltage is required, and therefore a high power supply voltage is required for the amplifier 38, resulting in excessive power consumption. .

Next, the transformer 39 causes a correction current of opposite polarity to flow through the horizontal deflection coils 30, 31 in the same manner as in the embodiment of FIG. 1 described above. In the case of the embodiment shown in Fig. 1 described above, three vertical deflection coils were connected in series, but in this embodiment, three horizontal deflection coils are connected in parallel, so a dual circuit is used. ing.

Further, the horizontal deflection current described above is transmitted to the horizontal deflection coil 29,
39 and 31 in the same phase, no potential difference is generated across the secondary side of the transformer 39.

Therefore, in this embodiment as well, the same effects as in the embodiment shown in FIG. 1 described above can be obtained.

In this embodiment, an example of actual constants is shown below when the projection type demi-spray is an ultra-high-definition display with a horizontal scanning frequency of about 64 kHz.

Note that the wrinkles are the inductance of the horizontal deflection 29, 30, and 31, C1 is the capacitance value of the resonant capacitor 28, C8 is the capacitance value of the bypass capacitor 33, Ll is the inductance of the primary side of the transformer 39, and L2 is the secondary side of the transformer 39. The side inductance Ro is the resistance value of the detection resistor 40.

Lo = 200pH, C, = 4mtIF.

Cs = 0.4uF, L+ = 20μH.

Lz = 2mH, Ro = 0.5Ω Also, in this embodiment, by placing a filter having the same configuration as in Fig. 2 on the input side of the amplifier 38, the influence of the parasitic loss of DY can be reduced as described above. Compensation can be done using a similar method.

Furthermore, as a modification of this embodiment, it is obvious that an example in which a voltage feedback system is adopted for the amplifier 38 is also possible, similar to the relationship between the embodiment of FIG. 3 and the embodiment of FIG.

In the above, the method of differentially driving the red and blue DYs has been described for the three embodiments.

Furthermore, it is also possible to differentially drive the green and red DYs by adding a similar circuit.

Alternatively, it is also possible to adopt a method in which two sets of DYs, DY for green and red and DY for green and blue, are differentially driven.

The above explains V-KS distortion, H-LI, which are the main causes of color shift caused by the projection optical system (projection lens, etc.).
This concludes the explanation of the color shift correction circuit that corrects N distortion.

Incidentally, in addition to the above-mentioned ■-KS distortion and H-LIN distortion, the causes of color shift include directional variations in the projection optical system or directional variations in the electron gun inside the projection tube.
There is a type of distortion in which the three primary colors are shifted parallel to each other. In the conventional technology, in order to correct such distortion, C
A method was used in which a correction current such as a direct current was passed through Y. However, as described above, since CY has poor deflection sensitivity, a large amount of power consumption is required to correct it.

Therefore, as a fourth embodiment of the present invention, a color shift correction circuit that can correct not only the above-mentioned H-LIN distortion but also distortion in which the three primary colors are shifted parallel to each other in the horizontal direction will be described. Give an explanation.

FIG. 6 shows a fourth embodiment of the present invention.

In FIG. 6, the same components as in FIG. 4 are given the same reference numerals. In addition, 41, 42, 43 are chiller coils, 44 is a circular power supply for horizontal parallel movement of the green screen, 4
5 is a first color shift correction signal, 46 is a second color shift correction signal, 47.48 is a low frequency amplifier, 49.52 is a negative feedback amplifier, 50.53 is a transformer, 51.54 is a subtracter, 5
5.56 is a DC blocking capacitor.

Now, the operation of this embodiment will be explained.

In this embodiment, a method is adopted in which two sets of DYs, DY for green and red, and DY for green and blue, are differentially driven.

The amplifier 49 receives a first color shift correction signal 45, such as a signal for horizontally moving the red screen with respect to the green screen and a signal for correcting H-LIN distortion. , a signal for horizontally translating the blue screen with respect to the green screen, a signal for correcting H-LIN distortion, etc. are input as the second color shift correction signal 45, respectively.

Therefore, the amplifier 49 supplies the correction current to the amplifier 47 and the primary side of the transformer 50, and makes the waveform of the output voltage of the subtracter 51 similar to the waveform of the first color shift correction signal 45. Negative feedback works.

Similarly, the amplifier 52 supplies a correction current to the amplifier 48 and the primary side of the transformer 53, and the waveform of the output voltage of the subtractor 54 becomes similar to the waveform of the second color shift correction signal 46. Negative feedback will work.

On the other hand, the variable power supply 44 is used for parallel movement of the green screen in the horizontal direction, and controls the current flowing through the horizontal deflection coil 29 of the green DY.

Further, each inductance of the choke coils 41, 42, and 43 is selected to have an alternating current high impedance of about 20 times the inductance of the horizontal deflection coils 29, 30, and 31, respectively. Therefore, among the correction currents supplied from the amplifiers 47 and 48, the choke coils 41 and 43 receive the high frequency current of the horizontal scanning period, that is, H-
Although only a small amount of the signal component for correcting the LIN distortion flows, a sufficient amount of DC current and low frequency current of the vertical scanning period, that is, the signal component for moving the screen in parallel in the horizontal direction, flows. Further, among the currents supplied from the variable power source 44, a DC current and a low frequency current having a vertical scanning period sufficiently flow through the choke coil 42 as well.

As a result, the DC current and the low frequency current of the vertical scanning period, that is, the signal components for horizontally translating the screen, are supplied to the horizontal deflection coils 29, 30, and 31 of the DY, respectively, and the horizontal The directional translation and the horizontal translation of the red and blue screens relative to the green screen are performed with low power loss.

Further, the transformer 50 allows the correction current supplied to the primary side to flow from the secondary side to the horizontal deflection coils 29 and 30 of the green DY and red DY so that the polarities are opposite to each other. The correction current supplied to the next side is passed from the secondary side to the horizontal deflection coils 29 and 31 of the green DY and the blue DY so that the polarities are opposite to each other.

Further, the horizontal deflection currents flow through each of the horizontal deflection coils 29, 30, 31 in the same phase as in the embodiment shown in FIG. 4 described above.

Here, two windings are wound on each of the secondary sides of the transformers 50 and 53, and half of the current flows through each winding on the side connected to the horizontal deflection coil 29 of the green DY, so this side Set the number of turns of one to twice that of the other. Further, each of the two resistors arranged between both windings is a current detection resistor, and the resistance values thereof are similarly set at a ratio of 1:2.

By doing this, each horizontal deflection coil 29.3
The horizontal deflection current flowing in phase with 0.31 is the subtractor 51.
No voltage is generated at the output of 54, and only the correction current flowing in the opposite phase generates a voltage. Therefore, the correction current can be detected by the current detection resistor of the transformer 50.53 and the subtracter 51.54, and the above-mentioned amplifier 49
．． 52 negative feedback operations can be realized. Further, the horizontal deflection currents flowing in the same phase through the horizontal deflection coils 29, 30.31 do not generate a potential difference between both ends of the secondary side of the transformer 50.53.

As explained above, according to this embodiment, not only H-LIN distortion but also distortion in which the three primary colors are shifted in parallel in the horizontal direction can be corrected by DY as color shift correction. It is possible to eliminate the need for any horizontal auxiliary deflection coil in cY.

Next, as a fifth embodiment of the present invention, the above-mentioned V-KS
A color shift correction circuit that can correct not only distortion but also distortion in which three primary colors are shifted in parallel in the vertical direction will be described.

FIG. 7 shows a fifth embodiment of the present invention.

In FIG. 7, the same components as in FIG. 1 are given the same reference numerals. In addition, 61 is a first color shift correction signal;
2 is a second color shift correction signal, 63 is a third color shift correction signal, 64 is a subtracter, 65.degree. 67 is a low frequency amplifier, 66.
68 is a choke coil, 69.73 is a negative feedback amplifier, 7
0.74 is a transformer, 71.75 is a current detection resistor, 72
．． 76 is a subtracter, 77.78 is a DC blocking capacitor,
It is.

Now, the operation of this embodiment will be explained.

In this embodiment, a method is adopted in which two sets of DYs, DY for green and red, and DY for green and blue, are differentially driven.

As the first color shift correction signal 61, a signal (a low frequency signal) for vertically translating the green screen (substantially vertically translating the entire screen of the three primary colors) is sent to the subtracter 64. , the feedback voltage of the amplifier 3 is insufficient, so to compensate for this, the amplifier 3 acts to supply the vertical deflection coils 4, 5.6 of the DY with an in-phase signal equivalent to the first color shift correction signal. Electric current flows and parallel movement of the screen of all three primary colors is achieved. Note that the first color shift correction signal 61
Even if a high frequency signal is supplied to the subtracter 6-4, the amplifier 3 does not work effectively because the amplifier 3 originally handles low frequency signals of 60 Hz.

On the other hand, the amplifier 69 receives, as the second color misregistration correction signal 62, a signal for moving the red screen in parallel in the vertical direction, a signal for correcting V-KS distortion, etc., and the amplifier 73 receives the following signals: As the third color shift correction signal 63, a signal for vertically parallel translation of the blue screen or a V-KS signal is used.
A signal for correcting distortion is input.

Therefore, the amplifier 69 supplies a correction current to the amplifier 65 and the capacitor 77, and performs a negative feedback operation so that the waveform of the output voltage of the subtracter 72 becomes similar to the waveform of the second color shift correction signal 62. . Similarly, the amplifier 73 supplies a correction current to the amplifier 67 and the capacitor 78, and
The waveform of the output voltage of the subtracter 76 is the third color shift correction signal 6
A negative feedback operation is performed so that the waveform is similar to No. 3.

The correction current supplied to the amplifier 65 is supplied to the choke coil 6
6, only the DC current and the low frequency current of the vertical scanning period (i.e., the signal component for moving the red screen in parallel in the vertical direction) are extracted, and then the vertical deflection coil 5 of the red DY is moved as indicated by the white arrow α. Flows in a positive polarity direction. This is because, as described above, a constant current always flows in the opposite direction of the white arrow α due to the negative feedback operation of the amplifier 3. As a result, only the red screen can be vertically translated in parallel to the i-color screen and the blue screen.

Similarly, from the correction current supplied to the amplifier 67, only the DC current and the low frequency current of the vertical scanning period (i.e., the signal component for vertically moving the blue screen in parallel) are extracted by the choke coil 68. Thereafter, the current flows through the vertical deflection coil 4 of the green DY and the vertical deflection coil 5 of the red DY in such a manner that the direction of the white arrow β is positive. As a result, the green screen and red screen are vertically moved parallel to the blue screen, but for example, the green screen and red screen are moved upward by a certain amount in parallel relative to the blue screen. is equivalent to moving the blue screen downward in parallel to the green screen and red screen by that amount, so this means that only the blue screen is vertically moved parallel to the green screen and red screen. can be done.

In addition, the correction current supplied to the capacitors 77 and 78 is
Only the high-frequency current of the horizontal scanning period (i.e., the signal component for correcting V-KS distortion) is there.

and are supplied to the primary sides of transformers 70 and 74, respectively. The subsequent operations can be easily inferred from the embodiment shown in FIG. 1 described above, so the explanation will be omitted.

As explained above, according to this embodiment, not only V-KS distortion but also distortion in which the three primary colors are shifted vertically and parallel to each other can be corrected by DY as color shift correction. It is possible to eliminate the need for any vertical auxiliary deflection coils in C and Y.

In addition, by using this embodiment together with the embodiment shown in FIG. (high frequency current), and in this case, CY itself can be deleted. Therefore, in addition to simply reducing power consumption, it is possible to improve focus by changing the structure of the projection tube shown in Figure 11 and moving the electron gun closer to the DY side, thereby reducing the magnification of the electron lens. I can do it.

Examples of actual constants in the embodiment of FIG. 7 are shown below. Vertical deflection coil 4, 5.6 (2mH), parallel resistance 8, 9
．． 10 (100Ω), a detection resistor 15 (2Ω), transformers 70, 74, etc. are the same as in the embodiment shown in FIG. 1 described above. In addition, the current detection resistor 71.75 is 8Ω, the choke coil 66.68 is 20mH, and the DC blocking capacitor 7
7.78 is 5 μF.

The parallel resistors 8,9,10 in FIG. 7 are three choke coils 8" electromagnetically coupled to each other in FIG.

9”, 10° can be substituted.The constant value is 30 m 1 which is approximately 5 times the total for the total of 6 mH of vertical deflection coils 4 and 5.6.
If 4 is selected, the shunt loss of the vertical deflection current, which is an in-phase component, can be suppressed to about 20%. - On the other hand, regarding the high-frequency correction current, currents of opposite polarities flow through the choke coils 9' and 10', and the magnetic fluxes cancel each other out, so that the correction current can be efficiently applied to the vertical deflection coil 5.6.

FIG. 9 shows a sixth embodiment of the present invention.

In FIG. 9, the same components as in FIGS. 7 and 8 are given the same reference numerals. In addition, 80 is a coil that constitutes a choke transformer together with choke coils 8', 9', and 10', and 81 is a choke coil.

The coil 80 is applied with upper and lower pink notification distortion correction signals output from an amplifier for correcting upper and lower binction distortions (not shown).

Here, the vertical binction distortion is a rask-shaped distortion common to the three primary colors, which is not directly related to the distortion that causes color shift related to the present invention, and is caused by excessive deflection of the four corners of the screen toward the diagonal corners. There is a distortion that appears to be

This distortion is corrected by the correction signal described above in the choke coils 8' and 9'' forming the choke transformer.

This can be corrected by passing appropriate correction currents in phase through the vertical deflection coils 4, 5.6 through the 10°.

Here, the appropriate correction current is I shown in FIG. 5d.
This is a current having a waveform obtained by multiplying the H parabolic signal and the l2 sawtooth signal 1 shown in FIG. 1 using a separate multiplier.

Further, the choke coil 81 is provided to prevent the correction current for the above-mentioned vertical binkction distortion from flowing back to the amplifier 3 side, and its capacitance value is about 12 mH.

[Effects of the Invention] According to the present invention, the color shift between the three primary colors caused by the projection optical system can be corrected by using DY, whose deflection sensitivity is about twice as good as that of CY. The power consumed for the correction can be reduced to almost half compared to the conventional method, resulting in lower costs. Furthermore, since the power consumption is approximately halved, the amount of heat generated due to power consumption is also halved, thereby reducing the internal temperature within the projection display device and improving reliability.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing a first embodiment of the present invention, FIG. 2 is a circuit diagram showing a specific example of the filter 13 in FIG. 1, and FIG. 3 is a circuit diagram showing a second embodiment of the present invention. The circuit diagram, FIG. 4 is a circuit diagram showing the third embodiment of the present invention, FIG. 5 is a waveform diagram showing the signal waveforms of the main parts in FIG. 4, and FIG.
7 is a circuit diagram showing the fifth embodiment of the present invention, and FIG. 8 is a circuit diagram showing the fifth embodiment of the present invention.
9 is a circuit diagram showing a choke coil used as a substitute for 0, and FIG. 9 is a circuit diagram showing a sixth embodiment of the present invention.
Figure O is an explanatory diagram showing the relationship between the projection lens and the image projected on the screen in a general projection display. Figure 11 - Positions of the projection tube and DY, CY in a boat fishing projection display. FIG. 3 is a side view showing the relationship. Explanation of symbols 3.14.3B, 49, 52, 69.73...Negative feedback amplifier, 4,5.6...Vertical deflection coil, 11°39
．． 50, 53, 70.74...Trans, 12°35
... Multiplier, 13.21 ... Filter, 16...
Projection tube, 17...DY, 18...CY, 29,30
．． 31... Horizontal deflection coil, 36... Maximum value detector, 37... Changeover switch. Agent Patent Attorney Akio Namiki No. 11! 1 Chopsticks 2 Figure X3 @ 1 Figure 5G d Yu) -1/te\-~! 1Itj Figure 8 Figure *9 Figure

Claims (1)

[Claims] 1. A plurality of projection tubes that emit monochromatic light, a plurality of projection lenses arranged in front of each projection tube, and a plurality of projection lenses arranged in each projection tube to emit electron beams in each projection tube. In a projection display comprising a plurality of deflection coils for deflection and a deflection circuit for passing a deflection current through each deflection coil, a color shift correction signal generating means for generating and outputting a color shift correction signal; an amplifying means for amplifying and outputting the color misregistration correction signal from the color misregistration correction signal generating means; and transformer coupling means for flowing a correction current corresponding to the output signal, and the transformer coupling means is characterized in that the transformer coupling means is coupled to at least two of the deflection coils so as to flow currents of opposite polarities as the correction current. Color shift correction circuit for projection displays.