JP3223333B2 - Drive circuit for fluorescent display tube - Google Patents

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 method.

[0002]

2. Description of the Related Art In general, 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 a configuration of a grid and an anode of the fluorescent display tube. In the figure, A ₁ , A ₂ ,..., A _N are anodes, G ₁ , G ₂ ,.
G _N is the grid. In such a configuration, the anodes A ₁ , A ₂ ,... A _N sequentially emit light by sequentially scanning timing signals as shown in FIG. 4 from the right grid G ₁ to the left grid G _N. Is done.

[0003]

However, in the fluorescent display tube constructed as described above, when scanning is sequentially performed from the right grid or the left grid, characters displayed due to interference between the grid scan frequency and the filament driving frequency. Or, a figure may fluctuate, or a flickering phenomenon may appear in which the displayed character or figure appears to wave slowly from right to left or from left to right.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to prevent a display from fluctuating or flickering due to interference between a grid scan frequency and a filament driving frequency. And a driving circuit for the fluorescent display tube.

[0005]

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

[0006]

According to the present invention, the grid is scanned in a non-sequential manner, thereby reducing the occurrence of display fluctuation or flicker.

[0007]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a block diagram showing a configuration of an embodiment of a driving circuit for a fluorescent display tube according to the present invention. In FIG. 1, reference numeral 1 denotes a plurality of anodes A on which phosphor emitting portions are formed, a plurality of grids G covering the plurality of anodes A, and a filament for emitting thermoelectrons disposed above the plurality of grids G. A fluorescent display tube F arranged in a vacuum vessel, a filament driving circuit 2 for supplying a predetermined voltage to the filament F of the fluorescent display tube 1, and a non-sequential scanning of the grid G of the fluorescent display tube 1 A scan signal circuit for storing data in the scan order, a grid circuit 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 the grid signal in response to the grid signal An anode circuit that outputs a G display signal to the anode A.

Next, the operation of the driving circuit for the fluorescent display tube thus constructed will be described with reference to the grid timing signal shown in FIG. And if 64 the number N of grid G as shown in FIG. 3, the first signal S from the scan signal circuit 3 for storing data of non-sequential scan order to scan the grid G to the grid G ₁ for example through the grid circuit 4 And then grid G ₆₀ , grid G ₃₂ , grid G
_3, performs non-sequential scan by outputting a non-sequential scan signal in the order of the grid G _64. Next, when the 64 grids G are applied with signals in a non-sequential manner, 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, a character or a figure is displayed.

As another embodiment of the grid scanning method, a method of applying a scan signal for every eight grids will be described. First, a signal is applied to the grid G _1,
Scan in the order of grid G ₉ , grid G ₁₇ , grid G ₂₅ , grid G ₃₃ , grid G ₄₁ , grid G ₄₉ , grid G ₅₇ , and then grid G ₂ + 8n (n = 0,
1,..., 7) and scan the grid G ₃ +
8n, grid G ₄ + 8n, grid G ₅ + 8n, grid G ₆ + 8n, grid G ₇ + 8n, grids G ₈ + 8n
And then 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 interference between the grid scanning frequency and the filament driving frequency, thereby improving the display quality of the fluorescent display tube. An extremely excellent effect can be obtained.

[Brief description of the drawings]

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

FIG. 2 is a timing chart 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 the fluorescent display tube.

FIG. 4 is a timing chart showing a conventional scanning method of 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

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G09G 3/30 301

Claims (1)

(57) [Claims] 1. A plurality of anodes each having a phosphor light-emitting portion formed thereon, a plurality of grids covering the anodes, and a filament for emitting thermoelectrons disposed above the plurality of grids. In a vacuum vessel, the plurality of anodes are commonly connected to the plurality of grids and are led out of the tube, and the plurality of grids are individually drawn out of the fluorescent display tube. A scan signal circuit unit that stores data of the 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; An anode circuit section for outputting a display signal of the grid to an anode, and a driving circuit for a fluorescent display tube.