JPH0666929B2 - Variable aspect ratio drive device for flat panel CRT - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable aspect ratio driving device for a flat panel CRT using a line cathode.

2. Description of the Related Art As a configuration of a conventional flat panel CRT, as shown in FIG. 4, a fluorescent surface 1 is divided by a plurality of line cathodes 2 into a screen at equal intervals. Reference numeral 3 is a back scanning electrode for line-sequentially scanning the electron beam emitted from each of the line cathodes K _{1 to} K ₁₅ in the vertical direction, and reference numeral 4 is a horizontal deflection electrode for deflecting the electron beam in the horizontal direction. Reference numerals 5 and 6 are G ₁ and G ₂ electrodes for controlling the electron beam.

Drive device for flat panel CRT constructed as above
It will be described with reference to the drawings. FIG. 5a shows a 1H television signal to be displayed horizontally on the fluorescent surface 1. It is assumed that the horizontal width dimension l _H2 of the drawing shown in FIG. 4 is divided by 15 cathodes. For example, when l _H2 has an aspect ratio of 5: 3, 4:
When a signal with an aspect ratio of 3 is input as the signal shown in FIG. 5a, a signal expanded in the time axis is necessary to simultaneously horizontally scan each line cathode in the same 1H time, and its waveform is shown in FIG. It is shown in b. At this time, the area to be displayed is the part corresponding to the horizontal width dimension l _H1 , so the new K ₂ and K ₁₄
The 1H signal is part of the effective light emission period.

Problems to be Solved by the Invention However, in the above configuration, as described above, the timing of starting the signal of K ₂ does not coincide with the phase of H blanking. In other words, it is necessary to make a delay of the black level period ts, and after the original signal is written in the line memory, the read timing for creating the signal shown in FIG. Was.

In view of the above point, the present invention has an object to configure a flat panel CRT so that even when signals with different aspect ratios are displayed, the signal format is the same as when a normal full screen is displayed.

Means for Solving the Problems The present invention provides a drive device for a flat plate CRT including a plurality of line cathodes, electrodes for controlling an electron beam from the line cathodes, and a horizontal deflection electrode for each of the line cathodes. , The number of line cathodes in two different aspect ratios,
The aspect variable drive device is characterized in that the divided area is configured so as to exactly match the amplitude width of the screen.

Operation According to the present invention, since the number of divisions of the screen by the line cathode is selected to be an integral multiple of the number of divisions derived from the two aspect ratios, the present invention can easily change the horizontal display area. it can.

First Embodiment FIG. 1 is a structural drawing for explaining a driving device for a flat panel CRT according to a first embodiment of the present invention. In FIG. 1, the same parts as those of the conventional structure are designated by the same reference numerals. In Fig. 1, the entire screen consists of N = 10 cathodes that can display an aspect ratio of 5: 3. When a signal with an aspect ratio of 4: 3 is used, K ₁ and K ₁₀ are selected. Blanking and l _{H1 in} the figure
Used with the dimensions.

The operation of this embodiment configured as described above will be described with reference to FIG. Figure 2d shows the standard operation when a signal with a 5: 3 aspect ratio is used. A 1H television signal is equally divided into 10 cathodes, time-axis extended, and simultaneously read from K ₁ to K _10. . Corresponding to each of the picture element blocks 1 to 10, the cathode signal is in agreement with the H blanking phase. next,
When a 4: 3 aspect signal is received, as shown in Fig. 2b,
Again, all signals are equally divided to create a 1H signal that can be read simultaneously. At this time, as shown in the figure, divided into eight 'to 8' 1 to, K ₁ and K ₁₀ would be a constant signal state until completely black level or blanking level. By operating in this way, the original signal of 4: 3 is exactly displayed in the part indicated by l _H1 in FIG. 1, and the signals of 8 blocks from K ₂ to K ₉ are divided into the same phase and the same phase. It becomes a signal of, and it becomes the same operation mode as when it is 5: 3, and it can be seen that the circuit processing method can be done only by the blanking control of the cathodes on both sides and the aspect conversion can be easily performed.

FIG. 3 shows a second embodiment of the present invention, in which the cathode for blanking display is changed when the aspect ratio is 4: 3 even though the number of divisions is the same. In the case of compatibility of 5: 3 and 4: 3, the minimum number of divisions is 10, but the integer multiples of 20, 30 are no different from the basic idea of the present invention.

In the embodiment shown in FIG. 3b, the cathodes of K ₁ and K _{2 which} are not displayed can be modulated independently of the electrodes of the main display, so that another image display of, for example, 5: 3 can be performed simultaneously. Conventionally, since electrodes on a part of boundaries are partially modulated, such a driving method requires a complicated circuit.

EFFECTS OF THE INVENTION As described above, according to the present invention, the aspect can be changed very easily by changing the horizontal amplitude and the power consumption can be increased without increasing the power consumption. This is the traditional
It is electrically stable compared to the case where the horizontal width of the deflection current is changed on the CRT to display the aspect variable.

The high-definition television that is being developed recently is aimed at wide aspect ratio, so the screen size is designed to be 5: 3, for example, when considering the conventional 4: 3 compatibility display. Needless to say, horizontal adjustment is necessary. In a general CRT, it is common to use a standard size for a 4: 3 screen and set the vertical amplitude to 5: 3, but this is a high quality that aims for a wider and higher definition image. In the TV mode, the screen becomes small and the wide feeling is reduced, but according to the present invention, the aspect variable can be ideally performed.

Of course, in Fig. 1, the mode of aspect 1: 1
It is self-evident that the divided areas can be made exactly the same.

[Brief description of drawings]

FIG. 1 is a block diagram of a variable aspect ratio driving device for a flat panel CRT in one embodiment of the present invention, FIG. 2 is an operation waveform diagram for explaining the same, and FIG. 3 is a flat plate in another embodiment of the present invention. CRT aspect ratio variable drive device configuration diagram, Figure 4 is a conventional flat plate CRT aspect ratio variable drive device configuration diagram,
FIG. 5 is a waveform diagram for explaining the apparatus. 1 ... Fluorescent surface, 2 ... Line cathode, 3 ... Rear scanning electrode, 4 ... Horizontal deflection electrode.

Claims (2)

[Claims] 1. A plurality of line cathodes for vertically dividing a screen, and electrodes for controlling an electron beam from each line cathode.
A rear scanning electrode for line-sequentially scanning the electron beam, a horizontal deflection electrode for horizontally deflecting and scanning the electron beam, and a fluorescent surface are provided, and the number of the line cathodes displays images with different aspect ratios. Sometimes, the aspect ratio variable drive device of the flat panel CRT is configured so that the number of divided areas is exactly the same. 2. When an aspect with a small horizontal amplitude is displayed, different video signals are output in an area corresponding to a line cathode that does not display anything. Aspect ratio variable drive device of the flat panel CRT according to the item.