JP3234095B2 - Liquid crystal display - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display using a television signal processing circuit for outputting an interpolation scanning line.

[0002]

2. Description of the Related Art Interlaced scanning is used in NTSC televisions. Therefore, one frame is formed by two fields. One field is composed of 262.5 scanning lines, and 1/60
Sent every second. Therefore, one frame is 52
It consists of five scanning lines and is sent every 1/30 second.

In the case of moving images such as sports,
Since the images of the two fields are different from each other, it is difficult to see the screen of the frame obtained by combining them.

Therefore, in the television signal processing circuit disclosed in Japanese Patent Application Laid-Open No. 63-171886, the number of scanning lines is doubled by interpolation, thereby obtaining a high-quality image.

This television signal processing circuit includes delay memories 14 to 16 as shown in FIG. The television signal (for example, the luminance signal Y) input to the input terminal 12 is delayed by 262H and 263H (H is a horizontal scanning cycle) in the delay memories 14 and 15, respectively.

For this reason, at the time when the television signal S3 corresponding to the pixel P in the third field is input to the input terminal 12, the delay memory 15 stores, as shown in FIG. And outputs a television signal S1 corresponding to the pixel P of the delay memory 14
Outputs a television signal S2 corresponding to a pixel on the scanning line n in the second field.

[0007] The subtraction circuit 19 outputs the difference (S1-S3) between the television signals S1 and S3. Coefficient circuit 20
Outputs a motion coefficient k representing the degree of motion of the video based on the difference (S1-S3). Here, 0 ≦ k ≦ 1.

The delay memory 16 stores the television signal S
2 is delayed by 1H. That is, in the delay memory 16, the television signal S2 'on the scanning line l (= n-1)
Is obtained. The adding circuit 17 outputs the sum (S2 + S2 ') of the television signals S2 and S2'. Coefficient circuit 1
8 outputs their average value a based on the sum (S2 + S2 ').

[0009] Multiplication circuits 21 and 22 and addition circuit 23
Outputs a luminance signal Y represented by the following equation in order to form a pixel Q on the pseudo scanning line m between the scanning lines 1 and n in the second field.

Y = kb + (1-k) a where b is the television signal S1 of the first field.
(Or, the television signal S3 of the third field)
It is.

According to this calculation, in the case of an image having a lot of motion, the weight of the adjacent scanning lines 1 and n in the same field is increased in the luminance signal Y, and in the case of an image having a little motion, the scanning lines of the preceding and succeeding fields are made. Weight increases.

The television signal S2 from the delay memory 14 and the television signal for interpolation from the adder circuit 23 are sent to a switch circuit 26 via time axis conversion circuits 24 and 25, respectively. Output alternately. Thereby, a high-quality image is obtained. The time axis conversion circuits 24 and 25 compress the horizontal scanning period H by half.

[0013]

However, in the above-mentioned conventional configuration, the delay memory 16 for delaying 1H,
Since the addition circuit 17 and the coefficient circuit 18 for obtaining the average value a are required, there is a problem that the cost is increased.

Further, in the case of a color television signal, there is a problem that a high quality image may not be obtained.

That is, since a color television signal uses an I signal and a Q signal (or an RY signal and a BY signal) as color signals in addition to the luminance signal Y, an edge portion of an image is used. In a fine pattern portion, the original luminance signal Y is mixed into the Q signal separated from the color television signal, or a part of the Q signal is mixed into the luminance signal Y. That is, the polarity inversion of the Q signal is not performed correctly. Therefore, even a still image may be regarded as having a motion. Therefore, even for a still image, interpolation may be performed using adjacent scanning lines 1 and n in the same field. As a result, the image quality deteriorates.

[0016]

A liquid crystal display device according to the present invention.
In order to solve the above problems ,
LCD monitor drive circuit and three television signal processors
A liquid crystal display device comprising a
The signal processing circuit compares the current television signal with the television signal one frame before to determine whether there is any image movement, and the determination means has determined that there is image movement. At this time, as the television signal of the interpolation scanning line, two adjacent signals in the current field are used.
When one of the television signals of one scanning line is selected and the determination means determines that there is no motion of the image, the television signal of the scanning line one field period before is selected as the television signal of the interpolation scanning line. and a switch circuit
And which, the determination means includes a first field memory for one field period delays the television signal, the first
Motion detection for detecting a motion of an image by comparing the current television signal with the output of the second field memory, which delays the output of the field memory by one field period, and compares the current television signal with the output of the second field memory. A determination circuit that determines whether or not there is image movement based on the detection signal and outputs a determination signal to the switch circuit. The determination circuit includes a detection signal from the motion detection circuit and a reference signal. comparing an adder for outputting a signal obtained by adding the value Th _1, a subtractor for outputting them by subtracting signals, the signal with a respective reference value Th ₂ and an output signal from the subtractor from the adder and an arithmetic circuit for outputting said judgment signal by, and the three
Television signal processing circuit for each of the RGB signals
To determine if there is any image movement
The method is characterized in that an interpolation scanning line is created for each of the signals and sent to the driving circuit .

[0017]

According to the configuration of the liquid crystal display device , a television signal of an interpolation scanning line can be easily obtained depending on whether or not there is a motion of an image. Moreover, when there is motion in the image, one of the television signals of the two scanning lines before and after the interpolation scanning line is selected as the television signal of the interpolation scanning line. The calculation circuit required is not required. This makes it possible to obtain high quality images at low cost. According to the determination circuit, even if the detection signal from the motion detection circuit includes a noise component or a jitter component, an accurate determination signal can be obtained by appropriately determining the reference values Th ₁ and Th _2. Can be.

Further, according to the configuration of the liquid crystal display device,
Since three television signal processing circuits are used, R
An interpolation scanning line can be easily obtained for each of the GB signals. In addition, since it is determined whether or not there is any image movement for each of the RGB signals, it is possible to make an accurate determination. Thus, a liquid crystal display device capable of displaying a high-quality color image at low cost can be realized.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS.

As shown in FIG. 1, the liquid crystal display device of this embodiment includes a television signal processing circuit 1 and a liquid crystal monitor 1.
0, and a drive circuit 9 for driving a liquid crystal monitor 10 based on the output of the television signal processing circuit 1.

The above-described television signal processing circuit 1 includes field memories 2 and 3 (first and second field memories), a motion detection circuit 6 which detects a motion of a video and outputs a detection signal 6a, A determination circuit 7 (determination means) for determining whether or not there is a motion based on a detection signal 6a of the detection circuit 6; line memories 4 and 5; and the line memory 4 or 5 is selected according to the determination result of the determination circuit 7 And a switch circuit 8 for outputting as a television signal of the interpolation scanning line.

Here, the interpolated scanning line is a scanning line reconstructed from the original scanning line depending on whether or not there is image movement.

An NTSC television signal is input to a field memory 2, a line memory 4, and a motion detection circuit 6 via an input terminal 11.

The line memory 4 functions to delay the television signal by 1H.

The field memory 2 stores a television signal of one field and outputs the television signal to store the television signal in one field period (= 1/60).
(Seconds). Field memory 2
Output is a field memory 3 and a line memory 5
Entered as

The line memory 5 functions similarly to the line memory 4. Therefore, the line memory 5
A television signal delayed by one field period from the output of the line memory 4 is output.

The field memory 3 functions similarly to the field memory 2.

Therefore, as shown in FIG. 2, when the television signal S3 corresponding to the pixel P in the third field is input to the input terminal 11, the field memory 3
Outputs a television signal S1 corresponding to the pixel P in the first field just one frame before.

The motion detection circuit 6 includes a field memory 3
By adding or subtracting the television signal S1 from the input terminal 11 and the television signal S3 from the input terminal 11, a detection signal 6a indicating the degree of image movement is output.
The determination circuit 7 determines whether or not there is an image movement based on the detection signal 6a, and outputs a determination signal 7a.

The switch circuit 8 selects the output of the line memory 4 or the output of the line memory 5 in accordance with the judgment signal 7a from the judgment circuit 7, and outputs it to the drive circuit 9 as a television signal of an interpolation scanning line. .

When the determination circuit 7 determines that the pixel P (FIG. 2) on the scanning line 1 in the third field has a change (ie, has a motion), the signal of the pixel Q on the interpolation scanning line m , The output of the line memory 4, that is, the television signal S3 corresponding to the pixel P on the scanning line 1 of the third field (the same field) is selected.

On the other hand, when the judgment circuit 7 judges that there is no change in the pixel P (that is, there is no movement), the output of the line memory 5, that is, the signal of the pixel Q on the interpolation scanning line m, The television signal S2 corresponding to the pixel Q on the scanning line m 'of two fields (the immediately preceding field)
Select

For the sake of simplicity, as shown in FIG. 3A, the scanning line 1 of the first field is composed of pixels P1 to P3, and the scanning line m 'of the second field is composed of pixels Q1 to Q3.
And the scanning line 1 of the third field is composed of pixels P1 to P3
And consist of Here, the scanning lines l and m 'are adjacent on the frame.

As shown in FIG. 3B, the motion detecting circuit 6 and the judging circuit 7 determine the pixels P1 to P3 of the scanning line 1 in the third field and the pixels P1 to P3 of the scanning line 1 in the first field.
3 respectively, pixel P1 is the same (ie, no motion), pixel P2 is different (ie, motion),
It is assumed that the pixel P3 is determined to be the same (that is, no motion).

In this case, the switch circuit 8 includes the pixel Q1,
An interpolation scanning line m composed of the pixel P2 and the pixel Q3 is output.
That is, when there is motion, the pixel Q2 in the second field
Is used, the pixel P2 of the third field (the same field) is used.

The drive circuit 9 drives the liquid crystal monitor 10 based on the output of the switch circuit 8, that is, the output of the television signal processing circuit 1.

As described above, according to the television signal processing circuit 1 of the present embodiment, the television signal of the interpolation scanning line m can be easily obtained according to whether or not there is a motion of the image. Moreover, when there is motion in the image, the television signal of the scanning line 1 before the interpolation scanning line m is selected as the television signal of the interpolation scanning line m. The calculation circuit required is not required.
This makes it possible to obtain high quality images at low cost.

The above determination circuit 7 is, for example,
As shown in FIG. 4, the detection signal 6a from the motion detection circuit 6
And the reference value Th ₁ and the adder 71 which outputs a signal 71a obtained by adding a subtractor 72 which outputs a signal 72a obtained by subtracting them, the output signals 72a from the subtractor 72 and the signal 71a from the adder 71 and a calculation circuit 73 which outputs a determination signal 7a indicating whether motion of an image not there by comparing preparative with the reference value Th _2, respectively.

[0039] (where, B indicates a binary number), for example 100B detection signal 6a from the motion detection circuit 6 and then, when the reference value Th ₁ and 010B, the signal 71a 1
10B, and the signal 72a becomes 010B.

The arithmetic circuit 73, for example, if the value ≧ reference value Th ₂ signal 72a, and outputs a determination signal 7a of the low level (no motion), if the value of the signal 72a <reference value Th _2, A high-level (moving) determination signal 7a is output. Further, determination may be performed in consideration of the result of comparison between signal 71a and the reference value Th _2.

According to the determination circuit 7, the motion detection circuit 6
Even detection signal 6a includes a noise component and the jitter component from, by determining the reference value Th _1, Th ₂ appropriately, it is possible to obtain an accurate determination signal 7a.

In the television signal processing circuit 1 of the present embodiment, when there is a motion in an image, pixels in different areas in the same field are used for interpolation. For this reason, the resolution decreases. However, since the resolution of eyes is lower than that of moving eyes, the reduction in resolution due to the above interpolation does not substantially hinder. Rather, since the pixel one field before is not used for interpolation, the edge of the moved portion does not have a comb-like shape, and a high-quality image can be obtained.

As described above, by using the television signal processing circuit 1 of this embodiment, it is possible to realize a liquid crystal display device capable of obtaining a high quality image with a simple configuration. The television signal processing circuit 1 is a CRT (cathode tube).
It can be widely applied to image display devices such as.

Further, as shown in FIG. 5, the provision of three television signal processing circuits 1 described above allows
An accurate interpolation scanning line m can be obtained for each of the signals. This is because it is determined whether or not there is an image movement for each of the RGB signals, so that the influence of mixing of the color signal and the luminance signal on the determination is basically eliminated, and accurate determination can be performed. Because you can. Thereby, a high-quality color image can be displayed.

Further, two television signal processing circuits 1 and 1 are provided for receiving television signals shifted by one field from each other, and interpolated scanning lines m from the television signal processing circuits 1 and 1 are alternately provided. , And sending the signal to the drive circuit 9, non-interlaced display can be performed on the liquid crystal monitor 10. Thereby, a higher quality image with less flicker can be obtained.

[0046]

As described above, the liquid crystal display device according to the present invention comprises a liquid crystal monitor, a liquid crystal monitor driving circuit,
DISPLAY DEVICE HAVING TWO TELEVISION SIGNAL PROCESSING CIRCUITS
Wherein each of the television signal processing circuits compares a current television signal with a television signal one frame before to determine whether or not there is image movement, and there is image movement. When the determination means determines that the television signal of the two adjacent scanning lines in the current field is selected as the television signal of the interpolation scanning line, and the determination means determines that there is no image movement. , As the television signal of the interpolation scanning line, 1
A configuration in which a switch circuit for selecting the television signal field period previous scanline. Further, the determination means includes a first field memory for delaying the television signal for one field period, a second field memory for delaying the output of the first field memory for one field period, and a current television signal. A motion detection circuit for detecting a motion of the image by comparing the output of the second field memory and outputting a detection signal, and a switch circuit for judging whether or not there is motion of the image based on the detection signal, And a determination circuit for outputting the result to the control circuit. Then, the determination circuit includes an adder for outputting a detection signal and the reference value Th ₁ and the signal obtained by adding from the motion detection circuit, a subtractor for outputting them by subtracting signals, the signal from the adder a configuration in which an arithmetic circuit for outputting said judgment signal by comparing the output signal from the subtractor with a reference value Th _2, respectively.

According to this, the television signal of the interpolation scanning line can be easily obtained depending on whether or not there is an image movement. In addition, when there is motion in the image, the television signal of the interpolated scanning line is used as the television signal before and after the interpolated scanning line.
Since one of the television signals of one scanning line is selected, an arithmetic circuit for calculating an average value of the two scanning lines is not required. As a result, it is possible to obtain a high-quality image at low cost. Further, according to the determination circuit, even if the detection signal from the motion detection circuit includes a noise component or a jitter component, the reference values Th ₁ , Th
By properly determining ₂ , an accurate determination signal can be obtained.

[0048] The liquid crystal display device according to the present invention, the
Three television signal processing circuits are used for RGB signal
RG
Create interpolation scan lines for each of the B signals and use them in the drive circuit
It is a configuration to send .

According to this, an interpolated scanning line can be easily obtained for each of the RGB signals. Moreover, R
Since it is determined for each of the GB signals whether or not there is an image movement, it is possible to make an accurate determination.
Thus, there is an effect that a liquid crystal display device capable of displaying a high quality color image at low cost can be realized.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic configuration of a liquid crystal display device according to the present invention.

FIG. 2 is an explanatory diagram showing an operation of a television signal processing circuit in the liquid crystal display device of FIG.

FIG. 3 is another explanatory diagram showing the operation of the television signal processing circuit in the liquid crystal display device of FIG.

FIG. 4 is a block diagram illustrating an example of a determination circuit in the liquid crystal display device of FIG.

FIG. 5 is a block diagram illustrating a schematic configuration of a liquid crystal display device using RGB signals.

FIG. 6 is a block diagram illustrating a schematic configuration of a conventional television signal processing circuit.

FIG. 7 is an explanatory diagram illustrating an operation of the television signal processing circuit in FIG. 6;

[Explanation of symbols]

REFERENCE SIGNS LIST 1 television signal processing circuit 2 field memory (determination means, first field memory) 3 field memory (determination means, second field memory) 6 motion detection circuit (determination means) 7 determination circuit (determination means) 8 switch circuit 9 Drive circuit 10 LCD monitor

Continuation of the front page (56) References JP-A-63-156487 (JP, A) JP-A-4-157886 (JP, A) JP-A-61-206385 (JP, A) JP-A-63-132584 (JP) JP-A-1-18687 (JP, A) JP-A-62-72287 (JP, A) JP-A-62-26967 (JP, A) JP-A-1-303886 (JP, A) 2-217083 (JP, A) Japanese Utility Model Application Hei 3-24788 (JP, U) Japanese Utility Model Application Hei 3-61781 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04N 7/01

Claims (1)

(57) [Claims] 1. A liquid crystal monitor and a driving circuit of the liquid crystal monitor
And a liquid crystal display having three television signal processing circuits
A television signal processing circuit comprising: a television signal processing circuit that compares a current television signal with a television signal one frame before to determine whether there is image movement; When the determining means determines that there is a video signal, one of the television signals of two adjacent scanning lines in the current field is selected as the television signal of the interpolation scanning line, and the determining means determines that there is no image movement. And a switch circuit for selecting a television signal of the scanning line one field period before as the television signal of the interpolation scanning line, wherein the determination means delays the television signal by one field period. A first field memory, a second field memory for delaying the output of the first field memory by one field period, and a current field memory. Revision signal and second
A motion detection circuit that detects the motion of the image by comparing the output of the field memory and outputs a detection signal;
A determination circuit that determines whether or not there is image motion based on the detection signal and outputs a determination signal to the switch circuit. The determination circuit includes a detection signal from the motion detection circuit and a reference value Th _1. It said by comparing Doo and an adder for outputting a signal summing them and a subtractor for outputting a signal subtraction with the signal from the adder and the respective reference value Th ₂ and an output signal from the subtracter And an arithmetic circuit for outputting the determination signal of the above.
Judge whether there is movement of the image for each
Interpolation scanning lines are created for each of the RGB signals,
A liquid crystal display device, which is sent to a road.