JPS6243191B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for driving a fluorescent display tube capable of analog display using digital signals.

The display tubes used for displaying numbers, which are generally used in calculators, etc., are designed to display digital signals using digital signals, and this is also a characteristic compared to mechanical displays. was.

However, over the years, we have become accustomed to mechanical, primarily analog displays, and there is some resistance to converting everything to digital displays.

In fact, there is a strong demand for analog displays, such as car speedometers that are checked conceptually while driving, and other displays that are generally difficult to read due to rapid quantitative fluctuations.

The present invention relates to a system that provides a substantially high-quality analog display by incorporating analog elements into a method for driving a fluorescent display tube, which has an improved structure suitable for converting the display tube into an analog display.

The present invention will be explained below using the drawings.

FIG. 1 is an explanatory diagram of an example of a conventional segment type fluorescent display tube, in which an electrode or filament F as a triode, a plurality of grids G ₁ , G ₂ , . . . , and a plurality of anodes A ₁ , A ₂ , . (Each anode A ₁ , A ₂ , . . . is composed of seven segments arranged in a sun-shaped pattern) is assembled on a substrate 2,
It is held in a vacuum container by covering it with a cover glass 1 and vacuum sealing the periphery.

The terminals of each electrode, as shown by the filament terminal 3, the grid terminal 4, and the anode terminal 5, are led out to the outside and are controlled by externally applied voltages.

In this case, the plurality of anodes A ₁ , A ₂ , .
G ₁ , G ₂ , . . . are arranged to face the anodes A ₁ , A ₂ , . . . respectively, and are formed in a mesh shape. Further, a filament F is stretched such that a grid is inserted between the filament F and the anode, and functions as an electron source.

First, a filament voltage is applied to both ends of the filament terminal to heat it so that it can emit thermoelectrons, and the electron flow is drawn out or suppressed depending on the potential applied to the space charge control grid on the front side. Furthermore, the electrons that have reached the grid are selectively accelerated by the anodes A ₁ , A ₂ , . . . and collided with the surface of the phosphor to emit light, thereby displaying numbers.

FIG. 2 is an example of the electrode structure of a fluorescent display tube that has been implemented for conventional analog display.
For convenience of explanation, a cover glass is not shown. That is, in the example of a bar graph, a single grid G and a plurality of anodes A ₁ , A ₂ , . . . , AN arranged in a bar shape are arranged in one example. The filament works in the same way as described above (positive voltage is applied to multiple grits, and when positive voltage is sequentially applied to the anodes to be lit, the display length expands and contracts in an analog manner, and for the time being analog However, since no light is emitted between the anodes, the display is still changing digitally, and is not a continuous analog display in the truest sense.

The present invention provides a method for driving a fluorescent display tube to obtain high quality analog display.

FIG. 3 shows an embodiment of a fluorescent display tube to which the driving method of the present invention is applied. As in FIG. 2, the cover glass is not shown for simplicity. The filament F is exactly the same as in Fig. 2, but in the present invention, the anode has a continuous structure, and the grid is G ₁ ,
G ₂ ,..., GN, and each anode grid is connected to grid terminal 4-1 so that it can be driven independently.
~4-N is provided. To display an analog display using a fluorescent display tube with this structure, first apply a positive voltage to the anode, and then sequentially apply positive voltage to the grid where the light should be lit, and the display length will change accordingly. It expands and contracts in an analog manner to obtain an analog display. It goes without saying that the surface of the anode A that is bombarded by electrons, that is, the grid side, is coated with a phosphor. Further, the anode terminal 5 is adapted to mechanically hold the anode A and to electrically apply a voltage from the outer end of the display tube envelope.

The relationship between the voltage applied to the grid and the brightness obtained at this time is shown in FIG. In other words, there is a gap between the grid and the anode, so a positive voltage is applied to the grid.
The brightness between G ₁ and grid G ₂ is continuous, and furthermore, between grid G ₂ and grid G ₃ to which no positive voltage is applied, a continuous change in potential distribution is obtained, and the emission brightness of the anode is Since the brightness is also obtained in a form that has a correlation with the potential distribution, the brightness also changes continuously, improving display quality close to analog display.

Also, in this case, if the potential of the grid of the light-emitting/non-light-emitting converter is analogously adjusted to the intermediate potential, the brightness distribution in the case of VG ₂ < VG ₁ as shown in Figure 4 will be obtained, and the continuity of the analog display edge will be reduced. is further improved.

On the other hand, in order to improve the continuity of brightness in terms of shape, for example, as shown in Figure 5, the angle θ between the alignment angle of each grid and the direction of expansion/contraction of the bar graph display (indicated by the arrow) is set to an acute angle. , it is also possible to make the tip of the display expansion/contraction tapered (fifth)
figure).

As explained above, according to the present invention, a method for driving an analog display tube with improved continuity can be obtained.
High-quality analog display becomes possible.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of an example of a conventional numeric display tube, showing the prerequisite content and clarifying the basis of the explanation. Figure 2 is a front view of an example of a bar graph with the cover glass removed, showing the conventional technology;
The figure is a front view of an example of a bar graph realized by the present invention, with the cover glass removed. Figure 4 shows _the voltage _and brightness distribution when _the present invention is used, and clearly shows the effect. Figure b is a conceptual diagram showing the arrangement relationship, Figure b is a diagram showing the grid voltage and spatial potential distribution, and Figure c is a diagram showing the luminance distribution. FIG. 5 is a front view of another embodiment of the present invention with the cover glass removed. 1... Cover glass, 2... Substrate, 3... Filament terminal, 4, 4-1, 4-2,..., 4-N
... Grid terminal, 5, 5-1, 5-2, ... 5-
N...Anode terminal, F...Filament, G,
G ₁ , G ₂ ..., GN...grid, A, A ₁ , A ₂ , ...
AN...Anode, VG ₁ ... Potential of grid G ₁ , VG ₂
... Potential of grid G ₂ , VG ₃ ... Potential of grid G ₃ .

Claims (1)

[Claims] 1. A continuous anode display element having a filament and a phosphor formed on an insulating substrate opposite thereto, and a number of grids located between the filament and the anode display element and extending across the anode display element. In the method for driving a fluorescent display tube, a positive voltage is applied to the continuous anode display elements, and the potential of each grid is digitally controlled to continuously display a display figure. How to drive a light display tube.