JPH0550754B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for driving a fluorescent display tube that displays characters, figures, etc. using dots.

[Conventional technology]

Conventionally, dot matrix type fluorescent display tubes have been used to display characters, graphics, and the like. In this dot matrix type fluorescent display tube, a plurality of filaments, a grid, and an anode coated with a phosphor are arranged through a space, and in particular, as shown in _{FIG .} Anode (A ₁
~A _n ) are arranged so that they are orthogonal.

For example, the grid driver 1 scans the grid (G ₁ to _o ) and sequentially controls thermionic electrons from the filament (not shown), while the anode driver 2 displays the anodes (A ₁ to _{A n} ). A method has been used to obtain a desired display by controlling selection based on data.

[Problem that the invention seeks to solve]

However, in the conventional fluorescent display tube configured in this way, in order to configure a dot display screen of, for example, n rows x m columns, a grid (G ₁
~G _o ) and m anode control lines are required as external connection terminals to control the anodes (A ₁ ~A _n ), respectively. Drive elements for selectively controlling the control lines are also required as many as the number of control lines.
Therefore, the structure of the fluorescent display tube and the external connection method become complicated, resulting in an increase in manufacturing cost and an increase in the size of the device.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for driving a fluorescent display tube that eliminates the above drawbacks and reduces the number of control lines and driving elements.

[Means for Solving the Problems] In the method for driving a fluorescent display tube of the present invention, a plurality of filaments, grids, and anodes are disposed in a vacuum container with space therebetween, and at least the grids and the anodes are substantially separated from each other. Thermionic emission is carried out from the filaments of a fluorescent display tube arranged at right angles,
A method for driving a fluorescent display tube in which the anode is scanned in a time-division manner and a grid is selectively controlled by display data in correspondence with the scanning of the anode to obtain a desired display, the anode being coated with a phosphor. a plurality of first anodes arranged in parallel to each other, and a plurality of second anodes arranged in parallel to each other in the same direction as the first anode through the resistance layer from the first anode.
anode, and a plurality of first anodes are arranged correspondingly to each second anode,
The first anodes at the corresponding positions of the second anodes are commonly connected, and the commonly connected first anodes and second anodes are selectively controlled to perform time-division scanning.

〔Example〕

Next, embodiments of the present invention will be described using the drawings.

1 and 2 are a block diagram and a sectional view of a fluorescent display tube according to an embodiment of the present invention.

In FIGS. 1 and 2, a plurality of filaments F and grids G are in a vacuum container (not shown).
(G ₁ , G ₂ . . . G _o ) and anodes are arranged at regular intervals at right angles to the grid, and the anodes are m·l first anodes A1 having a narrow width coated with a phosphor. (NO11 _{, 12, ... ml), and m second anodes A 2 (} A ₂ -1, A ₂
-2, ..., A ₂ -m). Note that 20 is a glass substrate.

And each of the second anodes A2 has l first anodes.
Arrange the anodes A ₁ relatively, and each second anode
The first anodes A ₁ at corresponding positions on A ₂ are connected in common. That is, the second anode
The first anodes A1 of the corresponding NOs (11, ₂₁ , 31,..., _m1 ) arranged on A2-1 _, A2-2..., _A2 - _m are commonly connected. . Similarly,
NO(12,22,32,...,m2),(13,
23, 33, . . . , m ₃ ), etc., are _commonly connected.

Therefore, the control line of the first anode A1 connected to the first anode driver 21 is equal to the number l of first anodes arranged on one second anode. Also, since the number of control lines of the second anode connected to the second anode driver 22 is m, the number of control lines of the entire anode is m+l, which is lower than the number of control lines of the anode required in the conventional structure, m·l. This will be extremely rare. For example, when m=l, the number of control lines required in the conventional structure is ^m2 , but in this embodiment, it is only 2m.
Specifically, the number of control lines required in the conventional structure, which was 256, can now be reduced to 2256 = 32, and the number of driving elements required in the anode driver can be reduced accordingly. Therefore, the circuit design and manufacturing process are simplified, the cost is reduced, and the fluorescent display tube can be made smaller.

In the fluorescent display tube configured in this way,
It is possible to display n rows and m.l columns, that is, n.times.m.l dots, and the driving method thereof will be described below.

In FIG. 1, the data signal 24 to be displayed
is applied from the clock pulse generation circuit 25 to the data signal control circuit 26 along with clock pulses C and P. The control signal from the data signal control circuit 26 is input to the grid driver 23, and the grid driver 23 applies a grid voltage V _G corresponding to the data signal 24 to the grid G (G ₁ , G ₂ ...G _o ). .

On the other hand, the clock pulses C and P from the clock pulse generating circuit 25 are input to the scanning signal control circuit 27, and the scanning control signal from the scanning signal control circuit 27 is applied to the first anode driver 21 and the second anode driver 22.

The switching circuit that constitutes the first anode driver 21 and the second anode driver 22 is
It constitutes an AND circuit (logical product), and this AND
The circuit selects only the first anode A ₁ in the portion where the first anode A 1 _and the second anode A ₂ are simultaneously selected. Then, the matrix intersection with the grid to which the grid voltage V _G is applied is selected and emits light.

The selection of the first anode _A1 will be explained below using the circuit diagram shown in FIG.

In FIG. 3, one end of the first anode A ₁ is connected to a switch constituting the first anode driver 21.
S ₁ , S ₂ ..., Sl is open when selected and grounded when not selected, and the other end is connected to resistor R.
It is connected to one end of the second anode A2 via. The other end of the second anode A ₂ is connected to switches SW ₁ , SW ₂ , . . . that constitute the second anode driver 22.
Connected to the anode power supply terminal by SWm.
When selected, it is applied from the anode voltage _VO , and when not selected, it is open.

In the anode driver circuit configured in this way, when selecting the first anode of NO13, for example, only switch S ₃ of the first anode driver 21 is turned OFF, and only switch SW ₁ of the second anode driver 22 is turned ON. do it.
By this scanning, the anode voltage V _O is selectively applied to the first anode A1 of NO13.

In reality, the voltage of the selected first anode A1 is lower than V _O due to a voltage drop due to the beam current from the filament of the fluorescent display tube and the resistor R, but when the anode voltage V _O is corrected in advance. There is no problem if you set it a little higher.

〔Effect of the invention〕

As explained in detail above, according to the present invention,
The anode is composed of a first anode and a second anode, and a plurality of first anodes are arranged on the second anode via a resistance layer, and the corresponding first anode on each second anode is common. This connection reduces the number of anode control lines and their driving elements, and by selectively controlling the first and second anodes, a method for driving a fluorescent display tube that performs time-division scanning can be obtained, which is highly effective.

[Brief explanation of the drawing]

1 to 3 are block diagrams, cross-sectional views, and equivalent circuit diagrams of a fluorescent display tube according to an embodiment of the present invention,
FIG. 4 is a block diagram for explaining a conventional fluorescent display tube. DESCRIPTION OF SYMBOLS 1... Grid driver, 2... Anode driver, 20... Glass substrate, 21... First anode driver, 22... Second anode driver, 23... Grid driver, 24... Data signal, 25... ...Clock pulse generation circuit, 2
6...Data signal control circuit, 27...Scanning signal control circuit, A1...First anode, A2...Second anode, C/P...Clock pulse.

Claims (1)

[Claims] 1. Emitting thermionic electrons from the filament of a fluorescent display tube in which a plurality of filaments, grids, and anodes are disposed in a vacuum vessel with spaces between them, and at least the grids and anodes are arranged substantially at right angles to each other. A method for driving a fluorescent display tube in which a desired display is obtained by scanning the anode in a time-divisional manner and selectively controlling the grid according to display data in correspondence with the scanning of the anode. a plurality of first anodes coated with a phosphor and arranged in parallel to each other;
a plurality of second anodes arranged parallel to each other in the same direction as the first anode through a resistance layer, and each of the second anodes includes a plurality of the first anodes; are arranged in a corresponding manner, the respective first anodes at the corresponding positions of the respective second anodes are commonly connected, and the commonly connected first anodes and the second anodes are selectively controlled to perform time-division scanning. A method for driving a fluorescent display tube characterized by: