JP2602845B2 - Television receiver - Google Patents

Description

The present invention relates to a television receiver, and more particularly to a method for scanning a television receiver using a matrix display device.

(Prior Art) In a broadcasting system such as NTSC, interlaced scanning is performed. In a television receiver using a CRT, it is not necessary to scan by distinguishing between odd and even fields. However, in a television receiver using a matrix type display device, it is necessary to alternately switch a scanning electrode group to be selected for each field corresponding to interlaced scanning.

(Problems to be Solved by the Invention) By the way, when the signal-to-noise ratio of the received signal is not sufficiently large, for example, when receiving a broadcast with a weak electric field, it is difficult to correctly distinguish the odd field from the even field. Have difficulty. In such a case, the judgment of even / odd of the field may be erroneously made, and the wrong scan electrode group may be selected.
The upper and lower sides of the image displayed every two scanning lines are switched, and the image cannot be reproduced correctly.

The present invention provides an image which is not unnatural even when it is difficult to correctly determine even / odd of a field by performing interlaced scanning and correctly reproducing a television broadcast, while receiving a broadcast with a weak electric field. It is an object of the present invention to provide a television receiver using a matrix-type display device capable of displaying an image.

[Configuration of the Invention] (Means for Solving the Problems) The television receiver of the present invention includes a plurality of scanning electrodes and a plurality of signal electrodes, and is based on a selection pulse applied to the scanning electrodes. What is claimed is: 1. A television receiver including a matrix type display device for selecting and displaying a video signal applied to a signal electrode, comprising: field determination means for determining an odd field and an even field from the video signal; and an odd field of the video signal. Switching means for selectively setting a state in which display is performed by simultaneously applying a selection pulse to two adjacent scan electrodes of the display device as a set regardless of the even field, and receiving the odd field. When it is difficult to determine whether the data is being received or an even field is being received, two adjacent scan electrodes of the display device are selected as a set and selected simultaneously. By applying a vinegar can be performed display.

(Operation) When it is difficult to determine whether an odd field is being received or an even field is being received, two adjacent scanning lines of the matrix type display device are simultaneously selected and scanned. It does not mean that the images displayed every two lines are reversed and the images cannot be reproduced correctly.
In this case, the same image is displayed on other adjacent scanning lines that should not be displayed. In the next field, an image to be displayed on the other scanning line is also displayed on another scanning line adjacent to the scanning line. That is,
An image that should be displayed on separate scanning lines is displayed on two scanning lines with both odd and even fields superimposed. However, usually, since the images of adjacent scanning lines have a large correlation, unnaturalness is not caused as much as an image which is upside down, and a natural display can be obtained visually.

(Example) Hereinafter, the present invention will be described in detail with reference to examples.

FIG. 1 is a driving waveform of a scanning electrode of a display device in a television receiver using a matrix type display device according to an embodiment of the present invention. As a display device, an active matrix type liquid crystal display element having a pixel electrode provided at the intersection of a scanning electrode and a signal electrode via a thin film transistor was used. Since such a display device is already known, detailed description will be omitted.

FIG. 1A shows a driving waveform of a scanning electrode in the case of performing normal interlaced scanning. FIG. 2B shows a driving waveform of a scanning electrode when two adjacent scanning lines of a matrix type display device are simultaneously selected and scanned regardless of an odd field and an even field.

When it is possible to determine whether the field of the received image is even or odd, as shown in FIG. 1A, for example, in the odd field, the selection pulse Sp is applied to the odd scan electrodes S1, S3, S5, S7,. Are sequentially applied. As a result, the odd-numbered scan electrodes S1, S
Images are displayed sequentially on 3, S5, S7,. Then, in the even-numbered field, the selection pulse Sp is sequentially applied to the even-numbered scan electrodes S2, S4, S6, S8, ..., and the even-numbered scan electrodes S2, S4, S6, s
Display images sequentially on 8 ,,,. In this way, predetermined interlaced scanning is performed, and the television broadcast is correctly reproduced.

On the other hand, when it is difficult to determine whether the field is even or odd,
As shown in FIG. 1B, irrespective of the odd field and the even field, in both fields, the adjacent odd-numbered scan electrodes and even-numbered scan electrodes are paired to form the scan electrodes (S1, S2), (S3, (S4), (S5, S6), (S7, S8) ...
Are sequentially applied with the selection pulse Sp. That is, two adjacent scanning electrodes are selected at the same time, and the same image is displayed on the two scanning electrodes. In the next horizontal scanning period, scanning is performed sequentially so as to select the next two adjacent scanning electrodes.

FIG. 2 is a circuit configuration block diagram of a television receiver according to one embodiment of the present invention.

40 is an antenna, 42 is a tuner, 44 is an intermediate frequency amplification circuit, 46 is a video detection circuit, 50 is a display device drive circuit, 52
Is an audio detection circuit, 54 is an audio output circuit, 2 is a display device, and 58 is a speaker. 32 is a video signal.

FIG. 3 shows the details of the display device drive circuit 50. The matrix type display device 2 uses an active matrix type liquid crystal display element as described above, and has many scanning electrodes S and many signal electrodes D. The even-numbered electrode terminals S1, S3, S5, S7,... Of the scan electrode S are provided with a first scan electrode driving circuit 10, and the even-numbered electrode terminals S2, S4,.
The second scan electrode drive circuit 20 is connected to S6, s8,. Each scan electrode drive circuit 10, 20 is provided with a shift register 12, 22.
And level conversion circuits 14 and 24. The signal electrode D is connected to the signal electrode drive circuit 30.

The video signal 32 is input to the synchronizing signal extraction circuit 60, and applies shift clocks SC, SC to the shift registers 12, 22 of each of the scan electrode driving circuits 10, 20 for each horizontal scan. The output of the synchronizing signal extraction circuit 60 is input to a field determination circuit 62, which determines whether it is possible to determine whether the field to be received is an odd field or an even field. If it is possible to determine whether the field is even or odd, it is further determined whether the odd field is being received or the even field is being received, and the scan electrode driving circuit for the odd scanning line is started at the start of receiving the odd field. Strobe signal ST to 10 shift registers 12
BO, and a strobe signal STBE to the shift register 22 of the scan electrode drive circuit 20 for even scan lines at the start of image reception of the even field. On the other hand, when it is not possible to determine whether the field is even or odd, strobe signals STBO and STBE are applied to shift registers 12 and 22 of both scan electrode driving circuits 10 and 20 at the start of each field. Note that these strobe signals STBO and STBE are signals corresponding to the pulse Sp for selecting the scan electrode S, and are sequentially propagated in the shift registers 12 and 22 by the shift clock SC. Level conversion circuits 14, 24
Converts the outputs of the shift registers 12 and 22 to a predetermined level and drives the scan electrodes S.

On the other hand, the video signal 32 is input to the signal electrode drive circuit 30 via the video amplifier 66. The signal electrode drive circuit 30 samples the video signal for one scanning line based on the output of the synchronization signal extraction circuit 60. Then, the sampled video signal is supplied to the signal electrode D in synchronization with the selection pulse Sp of the scanning electrode of each of the scanning electrode driving circuits 10 and 20.

According to the television receiver of the present invention configured as described above, when it is possible to determine whether an odd field is being received or an even field is being received, the first signal is received.
As shown in FIG. 5A, odd-numbered scan electrodes corresponding to odd-numbered fields are sequentially scanned, and then even-numbered scan electrodes corresponding to even-numbered fields are sequentially scanned to perform interlace scanning, and a predetermined image is formed. Reproduce. On the other hand, when it is difficult to determine whether an odd field is being received or an even field is being received, as shown in FIG. 1B, two adjacent scanning electrodes are simultaneously turned on regardless of the odd field and the even field. When selected, the two scanning electrodes are sequentially scanned to reproduce a predetermined image. In this case, although the resolution is inferior to that at the time of normal image reproduction, the upper and lower sides of the image are not switched for each scanning line, and a natural display is obtained.

Various methods can be considered for determining whether it is difficult to determine the odd field and the even field. For example,
The field discriminating circuit detects that the signal identifying whether the field is an odd field or an even field changes irregularly. If the signal is irregular, it can be determined that it is not possible to determine whether the field is even or odd. Furthermore, the electric field strength of the received signal is detected, and if the electric field strength is weak, it can be determined that it is not possible to determine whether the field is even or odd. In the case of only color broadcasting without black and white broadcasting, the output of a color killer circuit can be used.

In the above-described embodiment, it is determined whether or not it is difficult to determine whether the field is even or odd. Based on the determination signal, the scanning lines of the matrix display device are determined according to the odd field and the even field. The state in which interlaced scanning is performed and the state in which two adjacent scanning lines of a matrix type display device are simultaneously selected and scanned regardless of an odd field and an even field are switched. The user may select and switch by himself.

[Effect of the Invention] As described above, according to the present invention, when it is difficult to determine whether an odd field is being received or an even field is being received, two adjacent scanning lines of a matrix display device are used. Are selected at the same time and scanning is performed, so even if it is difficult to determine whether the field is even or odd when receiving an image with a weak electric field, an image in which the scanning lines are switched upside down will not be displayed and A natural display is obtained.

[Brief description of the drawings]

FIG. 1 shows a driving waveform of a scan electrode of a display device in a television receiver using a matrix type display device according to an embodiment of the present invention. FIG. 2 shows a circuit configuration block of the television receiver of one embodiment. Figure 3
FIG. 1 is a diagram illustrating a drive circuit of a display device according to an embodiment.

Claims (1)

(57) [Claims] 1. A matrix type device comprising a plurality of scanning electrodes and a plurality of signal electrodes, wherein a matrix type device selects and displays a video signal applied to the signal electrode based on a selection pulse applied to the scanning electrode. In a television receiver including: a field discriminating means for discriminating an odd field and an even field from the video signal; and when the field discriminating means discriminates an odd field and an even field, the scanning electrodes are changed to an odd field and an even field. And a state where two adjacent scanning electrodes are simultaneously selected and scanned between consecutive odd and even fields when the field discriminating means cannot discriminate between an odd field and an even field. Switching means for selectively setting the Down receiver.