JPH06319097A - Display element driving device - Google Patents

Abstract

PURPOSE:To compensate the drop-out of a chrominance signal also in addition to a luminance signal. CONSTITUTION:During the detection period of a drop-out in an RF video signal (RF luminance signal) by a drop-out detector, a gate driver 11 turns off a thin film transistor(TR) 25 on a display part corresponding to the RF video signal so as to interrupt the supply of a video signal (original chrominance signal) to a corresponding capacitor 26. Consequently the video signal (original chrominance signal) stored in the capacitor 26 is not updated and the video signal one field stored in the capacitor 26 is displayed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display element driving apparatus suitable for use in a monitor integrated recording / reproducing apparatus in which a recording / reproducing apparatus such as a VTR or a still video camera is integrated with a monitor.

[0002]

2. Description of the Related Art A conventional monitor-integrated recording / reproducing apparatus in which a VTR and a monitor are integrated is constructed, for example, as shown in FIG. In FIG. 6, RF signals reproduced from a recording medium (not shown) such as a tape by two heads (not shown) provided on the rotary transformer 1 are supplied to preamplifiers 2a and 2b, respectively, and amplified. Then, it is supplied to the channel switcher 3. The channel switcher 3 switches the outputs of the preamplifiers 2a and 2b at a predetermined timing to generate a series of RF reproduction video signals. The high-pass filter 4 separates the RF luminance signal from this RF reproduced video signal and supplies it to the dropout compensation circuit 5. The dropout compensation circuit 5 is set to 1 when a dropout occurs.
This is a circuit for compensating with the RF luminance signal before H, and is configured as shown in FIG. 7, for example. That is, the RF video signal (R
The F luminance signal) is supplied to the fixed contact a of the changeover switch 35 and the dropout detector 34. The output of the change-over switch 35 is supplied to the 1H delay line 33 including a glass delay line and the limiter 6. The 1H delay line 33 delays the output (RF brightness signal) of the changeover switch 35 by 1H and fixes the fixed contact b of the changeover switch 35.
Supply to.

The dropout detector 34 monitors the RF luminance signal supplied from the high-pass filter 4, and when no dropout is detected in the RF luminance signal, switches the changeover switch 35 to the fixed contact a side as shown in the figure. Then, the RF luminance signal which is not delayed is output to the limiter 6 as it is, and when the dropout is detected, the changeover switch 35 is switched to the fixed contact b side (1H delay line 33 side) while the dropout is detected. The limiter 6 is made to output the RF luminance signal of 1H before. The dropout-compensated RF luminance signal is supplied to the FM demodulator 7, where it is demodulated into a video signal. After demodulation, the de-emphasis circuit 8 performs de-emphasis, and the low-pass filter 9 and the noise reduction circuit 30 remove noise. afterwards,
The adder 36 adds the reproduced signal reproduced by a circuit (not shown). The output circuit 31 uses the addition signal of the reproduction luminance signal and the reproduction color signal as an NTSC video composite signal, for example, in the LCD monitor unit 32.
Output to. The LCD monitor unit 32 drives predetermined pixels based on the output from the output circuit 31 to display an image.

[0004]

Thus, the dropout compensation has been conventionally performed, but since the delay line is relatively large and expensive, there is a problem of space and cost increase.

Further, the dropout compensation using the delay line is usually performed only for the RF luminance signal and not for the RF chrominance signal in view of the performance of the delay line and the cost.

The present invention has been made in view of the above problems, and an object of the present invention is to perform dropout compensation without using a delay line and also perform color signal dropout compensation.

[0007]

In order to achieve this object, a display element driving apparatus of the present invention comprises a plurality of capacitors for storing video signals and a plurality of display elements for displaying the video signals stored in the capacitors. Display means having a plurality of switching elements for supplying a video signal to the capacitor, a first driver for supplying a video signal to the capacitor through the switching element, and a switching pulse for generating a scanning pulse to turn the switching element on and off. A second driver for controlling and a dropout detecting means for detecting a dropout of the video signal, and when the dropout detecting means detects the dropout of the video signal, the second driver controls the switching element. Thus, the operation of supplying the video signal to the capacitor is stopped.

[0008]

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

1 and 2 are block diagrams showing the configuration of an embodiment of a display element driving apparatus according to the present invention. In the figure, the same components as those in FIG. 6 or 7 are designated by the same reference numerals, and a duplicate description will be omitted.

FIG. 1 differs from FIG. 6 in the configurations of the dropout detection circuit 10 and the LCD monitor section 19.
The dropout detection circuit 10 is configured as shown in FIG. That is, the RF video signal (RF luminance signal) supplied from the high-pass filter 4 is supplied to the limiter 6 as it is and to the dropout detector 34. Then, in the dropout detection circuit 10, the 1H delay line 33 and the changeover switch 35 shown in FIG.
Is not used, the dropout detector 34 is
When a dropout is detected in the F luminance signal, the dropout control signal is supplied to the gate driver drive signal generation circuit 17 of the LCD monitor unit 19 described below.

The LCD monitor section 19 is constructed as shown in FIG. In addition, the TFT in the LCD monitor unit 19
The (thin film transistor) LCD 15 is configured as shown in FIG.

In FIG. 3, the composite video signal output from the output circuit 31 is supplied to the source driver drive signal generation circuit 16 and the gate driver drive signal generation circuit 17.

The source driver drive signal generation circuit 16 includes
The primary color signals (R, G, B) are generated from the input video signal, and the timing signal is generated from the horizontal cycle signal and the vertical cycle signal included in the video signal to generate these primary color signals (R, G). , B) and the timing signal to the source driver 13, respectively. Based on these primary color signals (R, G, B) and timing signals, the source driver 13 is a thin film transistor of the TFTLCD 15 in which the primary color signals for one horizontal scanning are arranged in a horizontal direction via the source bus 14 at a predetermined timing. Output to 25 sources.

The gate driver drive signal generation circuit 17 includes
A gate enable signal is generated, a timing signal is generated based on a horizontal period signal and a vertical period signal included in the input video signal, and these gate enable signal and timing signal are output to the gate driver 11, respectively. The gate driver 11 receives the gate enable signal from the gate driver drive signal generation circuit 17. Based on the timing signal from the gate driver drive signal generation circuit 17, scanning pulses are applied to the respective gate buses 12-1, 12-2, ..., 1 as shown in FIGS.
2-n are sequentially supplied. A gate bus 12-i (i is a corresponding one of 1 to n) is connected to the gate of each thin film transistor 25 constituting the TFTLCD 15 as shown in the figure, and a source bus is connected to the source of each thin film transistor 25. 14 is connected, and further, the drain of each thin film transistor 25 has a capacitor 26 and a display element 2
7 is connected.

As the display element 27, a liquid crystal display element is used here. Therefore, a scan pulse is sent from the gate driver 11 to a certain gate bus 12-i (i is 1 to n).
Of the source bus 14 connected to the gate bus 12-i of the thin film transistor 25 is turned on.
The primary color signals from are accumulated, and the image for one horizontal scanning is displayed on the display element 27. Such an operation is repeated by sequentially supplying the scanning pulse to each gate bus 12-i (i = 1 to n), and an image corresponding to the video signal is displayed. The thin film transistor 2
After 5 is turned off, the video signal stored in the capacitor 26 is output to the display element 27 and an image corresponding to the video signal is displayed.

In the gate driver drive signal generation circuit 17 of the LCD monitor unit 19, when a dropout is detected in the RF video signal (RF luminance signal), the dropout detector 34 of the dropout detection circuit 10 to FIG.
A dropout control signal as shown in (e) is supplied. Then, the gate driver drive signal generation circuit 17
The output of the gate enable signal to the gate driver 11 is stopped while the dropout control signal is being input. As a result, the gate driver 11 is shown in FIG.
While the dropout detector 34 is detecting the dropout of the RF video signal (RF luminance signal) as shown in FIG. 2, the gate bus of the display unit corresponding to the RF video signal, here, for example, the gate bus 12-3 is displayed. The output of the scanning pulse is forcibly prohibited as shown by the dotted line in FIG.

Therefore, during the period in which the dropout of the RF luminance signal is detected, the primary color signal accumulated one field before is not updated as it is in the capacitor 26 where a new primary color signal is originally accumulated. And the primary color signal of one field before stored in the capacitor 26 is displayed by the display element 27.

As described above, during the period in which the dropout is detected, the video signal stored in the capacitor 26 is not updated, and the video signal one field before is displayed to compensate for the dropout. I'm trying to do. By utilizing the video signal of one field before stored in the capacitor 26, it is not necessary to use the conventional 1H delay line 33 shown in FIG. , G, B signals) are stored, the dropout compensation also has color components.

In the above embodiment, the capacitor 26 and the display element 27 are separate, but when a liquid crystal display element is used as the display element 27, the display element 27 itself substantially has a capacitor component. Therefore, the capacitor 26 need not be added.

The present invention is not limited to this embodiment, and various applications and modifications are conceivable without departing from the gist of the present invention.

[0021]

As described above, according to the display element driving apparatus of the present invention, the operation of controlling the switching element to supply the video signal to the capacitor while the dropout is detected by the dropout detecting means. Since the video signal stored in the capacitor is stopped and the video signal stored in the capacitor is not updated, it is possible to perform dropout compensation by the video signal before the predetermined field.

Further, since the video signal stored in the capacitor is used as it is, there is no loss of color from the image by the compensated video signal.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a display element driving device according to the present invention.

2 is a block diagram showing an embodiment of the dropout detection circuit 10 of FIG.

3 is a block diagram showing an embodiment of the LCD monitor unit 19 of FIG.

FIG. 4 is a circuit diagram showing an embodiment of the TFTLCD 15 shown in FIG.

FIG. 5 is a timing chart for explaining a moving body of the present invention.

FIG. 6 is a block diagram showing an example of a conventional display element driving device.

FIG. 7 is a block diagram showing an example of the dropout compensation circuit 5 of FIG.

[Explanation of symbols]

 10 Dropout Compensation Circuit 11 Gate Driver 12 Gate Bus 13 Source Driver 14 Source Bus 15 TFTLCD 16 Source Driver Drive Signal Generation Circuit 17 Gate Driver Drive Signal Generation Circuit 19 LCD Monitor Section 25 Thin Film Transistor 26 Capacitor 27 Display Element 34 Dropout Detector

Claims (2)

[Claims] 1. Display means having a plurality of capacitors for storing a video signal, a plurality of display elements for displaying the video signal stored in the capacitor, and a plurality of switching elements for supplying the video signal to the capacitor. A first driver that supplies the video signal to the capacitor through the switching element, a second driver that generates a scan pulse to turn on and off the switching element, and a dropout of the video signal is detected. And a dropout detecting unit for detecting the dropout of the video signal, the second driver controls the switching element to supply the video signal to the capacitor. A display element drive device characterized by stopping operation. 2. The display element drive device according to claim 1, wherein the display element is a liquid crystal display element, and the capacitor is equivalently provided to the liquid crystal display element.