JPH06180560A - Driving circuit for fluorescent display tube - Google Patents

Abstract

PURPOSE:To prevent the fluctuation or flicker of display by the interference of a grid scan frequency and a filament driving frequency. CONSTITUTION:This driving circuit is constituted by having a fluorescent display tube 1 which is formed by housing an anode A, a grid G and a filament F into a vacuum container, a filament driving circuit 2 which supplies a prescribed voltage to the filament F, a scan signal circuit 3 which stores the data of the non-sequential scan sequence of the grid G, a grid circuit 4 which outputs a non-sequential scan signal to the grid G in correspondence to the output signal of the scan signal circuit 3 and an anode circuit 5 which outputs the display signal of the grid G to the anode A in correspondence to the grid signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving circuit for a fluorescent display tube driven by a dynamic driving system.

[0002]

2. Description of the Related Art Generally, in dynamic driving of a fluorescent display tube, a grid is usually scanned sequentially from a right end grid or a left end grid. FIG. 3 is a plan view showing the configuration of the grid and the anode of the fluorescent display tube. In the figure, A ₁ , A ₂ , ... _AN are anodes, G ₁ , G ₂ ,.
G _N is a grid. In such a configuration, the anode A _1, A ₂ by sequentially scanning timing signal as shown in FIG. 4 from the right side of the grid G ₁ to the left of the grid G _N, progressive emission display · · · A _N To be done.

[0003]

However, in a fluorescent display tube having such a structure, when scanning is sequentially performed from the right grid or the left grid, the characters displayed by the interference between the grid scan frequency and the filament driving frequency are displayed. Alternatively, the figure may shake, or the displayed characters or figures may appear to flicker slowly from right to left or from left to right.

Therefore, the present invention has been made to solve the above-mentioned conventional problems, and an object thereof is to prevent the occurrence of display fluctuation or flickering due to the interference between the grid scan frequency and the filament driving frequency. Another object of the present invention is to provide a driving circuit of a fluorescent display tube capable of performing the above.

[0005]

In order to achieve such an object, the present invention corresponds to a scan signal circuit section for storing data in a non-sequential scan order of a grid and an output signal of the scan signal circuit section. And a grid circuit section for outputting a non-sequential scan signal to the grid, and an anode circuit section for outputting a grid display signal to the anode in response to the grid signal.

[0006]

In the present invention, non-sequential scanning of the grid reduces the occurrence of display fluctuation or flickering.

[0007]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a block diagram showing the configuration of an embodiment of a drive circuit for a fluorescent display tube according to the present invention. In FIG. 1, reference numeral 1 denotes a plurality of anodes A having a phosphor light emitting portion, a plurality of grids G covering the plurality of anodes A, and a thermoelectron emission filament arranged above the plurality of grids G. A fluorescent display tube F is arranged in a vacuum container, 2 is a filament drive circuit for supplying a predetermined voltage to the filament F of the fluorescent display tube 1, and 3 is a non-sequential scan for the grid G of the fluorescent display tube 1. A scan signal circuit 4 for storing data in the scan order, a grid circuit 4 for outputting a non-sequential scan signal to a grid G in response to a signal output from the scan signal circuit 3, and a grid circuit 5 for this grid signal. It is an anode circuit that outputs a G display signal to the anode A.

Next, the operation of the driving circuit for the thus-configured fluorescent display tube will be described with reference to the grid timing signal shown in FIG. As shown in FIG. 3, assuming that the number N of the grids G is 64, the signal S is first sent from the scan signal circuit 3 storing the data of the non-sequential scan order for scanning the grid G to the grid G ₁ via the grid circuit 4, for example. Applied, then grid G ₆₀ , grid G ₃₂ , grid G
₃ , the non-sequential scan signal is output in the order of the grid G ₆₄ to perform non-sequential scan. Next, when 64 grids G are non-sequentially applied with signals, scanning is repeated in the above order. At the same time, by applying a signal from the anode circuit 5 to the anode A in synchronization with the scan signal of the grid G, characters or figures are displayed.

As another embodiment of the grid scanning method, a method of applying a scan signal for every eight grids will be described. First, apply a signal to the grid G ₁ ,
The grid G ₉ , the grid G ₁₇ , the grid G ₂₅ , the grid G ₃₃ , the grid G ₄₁ , the grid G ₄₉ , and the grid G ₅₇ are scanned in this order, and then the grid G ₂ + 8n (n = 0,
1, ..., 7) Scan and continue to grid G ₃ +
8n, grid G ₄ + 8n, grid G ₅ + 8n, grid G ₆ + 8n, grid G ₇ + 8n, grid G ₈ + 8n
Scan in the order of and repeat this.

[0010]

As described above, according to the present invention,
By performing non-sequential scanning of the grid, it is possible to prevent the display from fluctuating or flickering due to the interference between the grid scanning frequency and the filament driving frequency. Therefore, it is possible to improve the display quality of the fluorescent display tube. An extremely excellent effect can be obtained.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of a driving circuit of a fluorescent display tube according to the present invention.

FIG. 2 is a timing diagram showing a method of scanning a grid by a driving circuit of a fluorescent display tube according to the present invention.

FIG. 3 is a plan view showing a relationship between a grid and an anode of a fluorescent display tube.

FIG. 4 is a timing diagram illustrating a conventional method of scanning a fluorescent display tube grid.

[Explanation of symbols]

1 VFD 2 filament drive circuit 3 scans the signal circuit 4 grid circuit 5 the anode circuit A ₁ to A _N anode G ₁ ~G _N grid

Claims (1)

[Claims] 1. A plurality of anodes having a phosphor light emitting portion formed thereon, a plurality of grids covering the anodes, and a filament for thermionic emission arranged above the plurality of grids. In the vacuum display, the plurality of anodes are commonly connected to the plurality of grids and led out of the tube in a vacuum container, and the plurality of grids are individually led out of the tube. A scan signal circuit unit that stores data in a non-sequential scan order of the grid; a grid circuit unit that outputs a non-sequential scan signal to the grid in response to an output signal of the scan signal circuit unit; And an anode circuit section for outputting the display signal of the grid to the anode.