JPH11234591A - Television receiver - Google Patents

Abstract

(57) [Summary] As the horizontal scanning frequency increases, the power consumption of the horizontal deflection circuit increases, and the deflection circuit becomes expensive, such as requiring an expensive transistor. A deflection control circuit (13) is provided for expanding a horizontal blanking period of a video signal and slowly returning the line within the expanded period. Further, with the expansion of the horizontal blanking period, the wide conversion circuit 8 increases the number of samples of the video signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a television receiver. The invention is particularly applicable to PCs (personal computers).
The present invention is suitable for use in a television receiver that performs horizontal deflection at a higher speed than a current standard television signal such as a signal or an HDTV signal, that is, displays a video signal having a high horizontal deflection frequency.

[0002]

2. Description of the Related Art Generally, as a driving method of a CRT (cathode ray tube) in a television receiver, deflection by a sawtooth wave is performed. For example, considering horizontal scanning,
By scanning the horizontal effective area during the rising period of the sawtooth wave,
The display is from left to right on the screen. on the other hand,
The fall period is a retrace period for horizontal scanning to return from the right end to the left end on the screen. At this time, image blanking is performed so that the returning scanning line is not displayed. This horizontal blanking period is set to about 20% of the horizontal scanning period.

[0003]

In recent years, the size of the screen of a television receiver has been increasing, and the screen size has been expanding due to widespread use of a wide aspect display. There is an increasing demand for a television receiver having a small depth (thin) in addition to a large screen. On the other hand, current standard television signals are also converted from interlaced scans to progressive scans and displayed for the purpose of suppressing line flicker interference and the like. Also, video signals having a higher horizontal scanning frequency than conventional television signals, such as high-vision signals and PC signals, are increasing, and the horizontal deflection frequency tends to be higher. For this reason, the power consumption of the horizontal deflection circuit is increased and an expensive transistor is required. Therefore, the cost of the deflection circuit, especially the horizontal deflection circuit, has become a major issue.

An object of the present invention is to solve the above-mentioned problems and to provide a television receiver at a low cost.

[0005]

In order to achieve the above object, a television receiver according to the present invention comprises a blanking period extending means for extending a horizontal video blanking period of a video signal; A deflecting means for expanding the retrace period within the period, and a display means driven by the deflecting means and displaying a video signal from the blanking period expanding means are provided. With such a configuration of the television receiver, it is possible to reduce the time change of the deflection current and reduce the power consumption of the deflection circuit.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIG. FIG. 1 is a block diagram showing one embodiment of a television receiver according to the present invention. In the figure, 1
Is a television signal input terminal, 2 is an HDTV signal input terminal, 3 is a PC signal input terminal, 4, 7 are switches, 5 is I
/ P (interlace / progressive) conversion circuit,
6, 9 are memories, 8 is a wide conversion circuit, 10 is a wide aspect CRT, 11 is a synchronization separation circuit, 12 is a synchronization generation circuit, 13 is a deflection control circuit, and 14 is an operation of the system according to a video signal to be displayed. It is a system controller that controls.

In the following embodiment, an example is described in which an NTSC signal is received as a television signal input.
Further, a case where a high-vision signal is received as an HDTV signal will be described as an example. The NTSC signal, the HDTV signal, and the PC signal input to the input terminals 1, 2, 3 are selected by the switch 4, and any one of the signals is output. First, a case where an NTSC signal is selected and displayed will be described. The NTSC signal is selected by the switch 4 and supplied to the motion adaptive I / P conversion circuit 5. Here, the NTCS signal is converted from interlaced scanning to sequential scanning. The motion adaptive I / P conversion circuit 5 is specifically described in, for example, Japanese Patent Application Laid-Open No. 2-81588, and a detailed description thereof will be omitted. The memory 6 is for storing the NTSC signal for one field before one field, and the signal from the memory 6 is used by the I / P conversion circuit 5 to create an interpolation scanning line for a still image. The switch 7 is switched so as to select an input or an output of the I / P conversion circuit 5. The television signal supplied to the wide conversion circuit 8 is converted from a standard aspect to a wide aspect by changing a writing frequency to the memory 9 and a reading frequency from the memory 9, and passes through a video amplification circuit (not shown). , Wide aspect CRT (cathode ray tube) 1
0 is supplied. In the synchronization separation circuit 11, a horizontal synchronization signal and a vertical synchronization signal are extracted from the NTSC signal selected by the switch 4 and supplied to the synchronization generation circuit 12.
The synchronization generation circuit 12 generates various pulses for driving the television receiver based on the horizontal synchronization signal and the vertical synchronization signal. A reset pulse, a gate pulse indicating the start and end of writing to the memory 6, and the like are supplied from the synchronization generation circuit 12 to the memory 6. Also, the I / P conversion circuit 5 is supplied with a pulse or the like for doubling the scan speed after the interpolation operation (interpolation operation such as intra-field interpolation and inter-field interpolation). A reset pulse and the like are supplied from the synchronization generation circuit 12 to the memory 9, and a write gate pulse, a read gate pulse and the like are supplied to the wide conversion circuit 8. Further, horizontal and vertical synchronization signals are supplied from the synchronization generation circuit 12 to the deflection control circuit 13, and horizontal and vertical deflection currents are supplied to the deflection coil 15. The system controller 14 controls the circuits so that the television receiver operates with control as a whole. For example, the switches 4 and 7 are controlled in accordance with the situation of which of the signals input to the terminals 1, 2, and 3 is selected by a signal from a remote controller (not shown).

When the HDTV signal supplied to the input terminal 2 is selected by the switch 4, the HDTV signal is input to the wide conversion circuit 8 by the switch 7, bypassing the I / P conversion circuit 5. In the wide conversion circuit 8, the read frequency or the number of samples is changed with respect to the write frequency and supplied to the CRT 10.
When the PC signal supplied to the input terminal 3 is selected by the switch 4, this signal is transmitted to the I / P
The signal is supplied to the wide conversion circuit 8 bypassing the conversion circuit 5, converted to a wide aspect, and supplied to the CRT 10. As described above, the wide conversion circuit 8 is a circuit that corrects an NTSC signal having an aspect ratio of 4: 3 to 16: 9, which is an aspect ratio of a wide display.

An example of this correction will be described with reference to FIGS. 2A, 2B, 2C and 2D are front views of a CRT for explaining wide conversion and blanking enlargement according to the present invention, and FIGS. 3A, 3B and 3C. FIG. 3 is a schematic diagram for explaining wide conversion and blanking expansion according to the present invention. For example, when a standard aspect image as shown in FIG. 2A is displayed on the wide aspect CRT 10, the left and right sides are expanded and displayed on the wide aspect CRT 10 as shown in FIG. 2B. To prevent this,
The video signal to be displayed may be compressed to 3/4 times in the time direction and displayed. By doing so, a normal circle as shown in FIG. 2C is displayed on the CRT 10. To compress a video signal to be displayed to 3/4 times in the time direction, the memory 9
The reading speed may be about 4/3 times faster than the writing speed. By changing the reading speed in this way, it is possible to display a standard aspect screen on about 3/4 of the wide aspect CRT 10, as shown in FIG. Note that the number of 3/4 times is calculated from the fact that the standard aspect ratio is 4: 3, that is, 12: 9, while the wide display is 16: 9. You can see that it needs to be compressed. As a specific example of the writing frequency, 910 times the horizontal scanning frequency fh is generally used. If this value is used, the frequency required for sequentially scanning and writing in the NTSC system is about 28.6 MHz.
Therefore, about 38.2 MHz, which is 4/3 times this, can be used as the read frequency. .

In this embodiment, the blanking period is extended simultaneously with the wide conversion. In FIG. 2A, assuming that the inside of the circle is bright and the other parts are dark, and the luminance of a horizontal line passing through the center of the circle is schematically displayed, FIG.
It becomes as shown in. In FIG. 3A, 1H represents one horizontal scanning time, and HBLK represents a horizontal blanking period. Assuming that the image of the standard aspect shown in FIG. 2A is corrected and displayed on the wide aspect CRT 10 as shown in FIG. 2C, the diameter of the circle in the horizontal direction of the screen as shown in FIG. The display time of a portion (bright portion) is relatively shorter than that of another portion (dark portion).
That is, when the state of FIG. 2A is changed to the state of FIG. 2C, the diameter portion (bright portion) of the circle is reduced as shown in FIG. 3B.

A case where the horizontal blanking period is further increased from the state shown in FIG. 3B as shown in FIG. 3C will be described. Now, in FIG. 3B corresponding to FIG. 2C, assuming that the number of data in one horizontal scan is A sample and the number of data of horizontal blanking is B sample, the blanking rate α is (α = B / A ). FIG.
As shown in (c), in order to increase the blanking rate n times and not decrease the number of displayed samples, the total number of samples and the number of samples in the blanking period may be increased. Assuming that the increased number of samples is x, the total number of samples Y is obtained as follows. New blanking rate = n × α = (B + x) / Y Here, from Y = A + x, x = YA Therefore, nxα = (B + YA) / Y α) Y = B + YA−Y = (AB) / (1−nα) = (1−α) A / (1−nα) Therefore, the memory 9 is used to extend the blanking period.
The read frequency of the video signal from the (1−α) / (1−
nα) times. Standard aspect NTSC
When displaying a signal on a wide aspect CRT 10,
In general, since A = 1200 and B is about 200 samples, α = 1/6. When this is extended to about 1.5 times, (1-1 / 6) / (1-3 / 2 × 1/6) = 10
/ 9, it is only necessary to increase the reading speed by about 10%. Even if the blanking period is expanded, the number of samples to be displayed does not decrease and the display can be performed while maintaining high image quality.

FIG. 3C shows a state in which the horizontal blanking period is further expanded from the state shown in FIG. 3B. In this case, the horizontal scanning time is shortened, but the horizontal scanning range can be made the same by making the peak value of the horizontal scanning current the same. If only the horizontal scanning period is simply shortened, the image quality deteriorates. However, the image quality can be prevented from deteriorating by increasing the number of samples of the video signal, that is, the read frequency by the wide conversion circuit 8. Therefore, even if the horizontal blanking period is increased, the display itself can be equivalent to the display of FIG. 2C as shown in FIG. When the horizontal blanking period is increased as shown in FIG. 3C, the deflection current output from the deflection control circuit 13 needs to be changed. Therefore, a control signal is supplied from the system controller 14 to the deflection control circuit 13. That is, the deflection control circuit 13 can be controlled by the algorithm of the system controller 14 so that the horizontal deflection current is changed and the horizontal scanning area is not changed. Further, an adjustment knob is provided on the front of the television receiver, and by adjusting this knob, the value of the horizontal blanking period can be adjusted by changing the algorithm of the system controller 14.

As described above, if the blanking period is increased to about 1.5 times the conventional value, the retrace period can be made about 1.5 times. For this reason, the voltage induced in the horizontal deflection coil 15 is the product of the inductance L of the coil and the time change of the current. Even if it is doubled, it is possible to keep the same induced voltage. When the deflection angle is the same, the deflection current can be reduced by increasing the inductance L.
Even when displaying signals, the same low-standard parts as before,
For example, a horizontal output circuit can be applied, and the cost of the deflection circuit can be reduced.

Next, the operation when the switch 4 selects an HDTV signal (in this case, a high-vision signal) will be described. In this case, since the switch 7 selects the output side of the switch 4, the HDTV signal is supplied to the wide conversion circuit 8 bypassing the I / P conversion circuit 5. Unlike the operation described for the NTSC signal, the wide conversion circuit 8 does not convert the aspect ratio, but simply performs processing for expanding the horizontal blanking period, that is, changes the read frequency from the memory 9 to reduce the number of samples. Is increasing. Although the specific operating frequency is different from that in the case of NTSC, the calculation of the number of increased samples due to the extension of the blanking period is the same, so that detailed description is omitted. Next, when the PC signal is selected by the switch 4, the switch 7
And the NTS signal is supplied to the wide conversion circuit 8 except that the PC signal bypasses the I / P conversion circuit 5 and is supplied to the wide conversion circuit 8.
The same applies to the processing of the C signal.

As described above, in this embodiment, the power consumption of the deflection circuit can be reduced by extending the horizontal blanking period of the input video signal. Therefore,
The deflection circuit, particularly the horizontal deflection circuit, can be constituted by low-cost components, and a low-cost television receiver can be realized. In the above embodiment, the NTSC signal has been described as an example of the television signal. However, the present invention is not limited to this.
The present invention is also applicable to a case where an ECAM signal or the like is input, converted to progressive scanning, and displayed. Similarly, the description has been made by taking a HDTV signal as an example of an HDTV signal, but the present invention is not limited to this. For example, the present invention is also applicable when inputting and displaying signals of various formats as discussed in the digital broadcasting system. It goes without saying that the application is possible. As the PC signal, for example, the number of effective pixels is 64.
0x480 standard PC signal or 800x effective pixels
Although there are 600 SVGA signals and the like, the present invention can be applied to these signals.

In the above embodiment, the motion adaptive processing is performed to convert the NTSC signal into the progressive scan. However, the NTSC signal may be converted into the progressive scan by the intra-field process. Further, in the above embodiment, the case where the television signal and the PC signal are displayed on the wide aspect CRT 10 has been described. However, the present invention can be applied to the case where these signals are displayed on the standard aspect CRT. In this case, in order to increase the number of samples, a conversion circuit for converting the frequency read from the memory 9 may be provided.

Further, in the above embodiment, when the blanking period is expanded, the entire number of samples is increased by the wide conversion circuit 8 so that the number of samples to be displayed is not reduced. , But
The present invention is not limited to this, and the number of blanking samples may be increased according to the increase rate of the horizontal blanking period without changing the total number of samples. For example, when the blanking period is enlarged to about 1.5 times and displayed, the number of samples in the blanking period may be increased to 3/2 times. In this case, there is an advantage that the blanking period can be extended without increasing the read frequency from the memory 9.

[0018]

The horizontal blanking period of the video signal is extended, and the deflection control circuit is controlled so as to return slowly during the extended period. Since low power consumption can be realized, a television receiver can be provided at low cost.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention.

FIG. 2 is a front view of a CRT for explaining wide conversion and blanking enlargement according to the present invention.

FIG. 3 is a schematic diagram for explaining wide conversion and blanking enlargement according to the present invention.

[Explanation of symbols]

1, 2, 3 ... input terminal, 4, 7 ... switch, 5 ... I / P
Conversion circuit, 6, 9, memory, 8 wide conversion circuit, 10
... wide aspect CRT, 11 ... sync separation circuit, 12
... Synchronization generation circuit, 13 ... Deflection control circuit, 14 ... System controller.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Kazuhiro Kaizaki 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Inside the Visual Information Media Division, Hitachi, Ltd. (72) Inventor Mitsuo Nakajima Yoshida, Totsuka-ku, Yokohama-shi, Kanagawa 292, Hitachi, Ltd. Multimedia System Development Division, Hitachi, Ltd.

Claims (6)

[Claims] 1. A blanking period extending means for extending a horizontal video blanking period of a video signal, and a deflecting means for extending a retrace period within the extended blanking period.
A display unit driven by the deflecting unit and displaying a video signal from the blanking period expanding unit. A memory for storing the video signal; a conversion circuit for writing the video signal to the memory, reading the video signal stored in the memory, and changing a read frequency; 2. The television receiver according to claim 1, wherein the read frequency is increased with an increase in a ranking period. 3. When the blanking rate before expanding the blanking period of a video signal is α and the expansion rate of the blanking period is n, the readout frequency of the conversion circuit is approximately ( 3. The television receiver according to claim 2, wherein the ratio is 1-α) / (1-nα) times. 4. An I / P conversion circuit for converting a television signal of a standard aspect of an interlaced scanning system into a television signal of a progressive scanning system, and an aspect ratio of the television signal converted into a progressive scanning system to a wide aspect. A wide conversion circuit for converting, a deflection control circuit for extending a horizontal blanking period by extending a horizontal blanking period of a video signal, a system controller for instructing the deflection control circuit to extend a horizontal blanking period, and a wide aspect ratio. A television receiver comprising: a cathode ray tube. 5. A wide conversion circuit for converting an aspect ratio of a standard aspect PC signal into a wide aspect, a deflection control circuit for expanding a horizontal blanking period of a video signal to extend a horizontal blanking period, and said deflection control circuit. A television controller comprising: a system controller for instructing a horizontal blanking period to be extended; and a wide aspect cathode ray tube. 6. A deflection control circuit for extending a horizontal blanking period by extending a horizontal blanking period of a video signal, a system controller for instructing the deflection control circuit to extend a horizontal blanking period, and storing a high vision signal. A memory, a conversion circuit for changing a writing frequency to the memory and a reading frequency from the memory, and a wide-aspect cathode ray tube, and increasing a reading frequency of the conversion circuit with an increase in the horizontal blanking period. A television receiver characterized by the above-mentioned.