JPS58117595A - Driving of fluorescent display unit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fluorescent display device and a method for driving a fluorescent display device that reduces power consumption by a significant percentage.

In general, most of the power consumed by the filament of a fluorescent display device comprising multiple digits is consumed by the filament.
Even in so-called zero suppression, which erases the display of zero in the upper significant digits, current is passed through the filament.
Power consumption is large regardless of the number of digits displayed. In particular, when battery drive is used, the life of the battery is significantly shortened.

Figures 1(f), 1←) and 1f') respectively show the filament driving method of a conventional multi-digit fluorescent display tube, and as an example, four fluorescent displays displaying four-digit numbers. This is the case when a tube is provided and its filaments are connected in series, in parallel, and in series and parallel. In the figure, 1a to 1d are fluorescent display tubes, 2a to 2d are filament electrodes of the fluorescent display tubes 111 to 1d, and 31 to 3d are the fluorescent display tubes 111.
~ldO grid electrode, 4a~4dij: this firefly yt,
Plate electrodes of the display tubes la to ld; 5 is a filament power source; 6 is a drive power source II, 71 for the fluorescent display tubes 11 to 1d;
8 is the filament power switch, usually the filament electrode 5
Although it is provided on the primary side of the transformer, for convenience of explanation, it will be described below as a filament power switch 8.

~Next, the display operation of the fluorescent display device having the above configuration will be briefly explained. First, filament power switch 8
When closed, the filament electrodes 21-2d of the fluorescent display tubes 111-1d are heated, and the fluorescent display tubes 13-1d are brought into operation. Therefore, by applying sequential pulses for selecting digits to the grid electrodes 38 to 3d, and applying signals of the display pattern for each digit to the plate electrodes 4a to 4d, the sequential pulses for selecting digits and the display turn signal are synchronized to provide a predetermined value. Predetermined characters can be displayed on the digits by dynamic lighting.

However, due to the power, in the driving method of the multi-digit fluorescent field display tube with the above configuration, the filament electrode is heated to the rated temperature even in the so-called non-lit digits, regardless of the number of displayed digits Kti, and the grid electrode is heated to the rated temperature. Since pulses are applied sequentially, power consumption of the filament electrode and grid electrode naturally occur. Therefore, the magnitude relationship of power consumption at each electrode of the firefly display tube can be shown as follows.

Filament electrode power consumption>Clid electrode power consumption>Plate electrode power consumptionThe sum of the power consumption of each electrode is the total power consumption of the fluorescent display tube. Here, most of the total power consumption is filament electrode power consumption), and the only power consumption that does not occur in non-lit digits is plate electrode power consumption.

In this way, multi-digit fluorescent display tubes, especially fluorescent display tubes with a large number of digits, have the disadvantage that the power consumption is close to the total power consumption, regardless of the number of lit digits. there were.

Therefore, the object of the present invention is to heat only the filament electrodes of the lit digits to the rated temperature, and not heat the filament electrodes of the non-lit digits, or to operate them at a preheating temperature lower than the rated temperature. Provided is a method for driving a fluorescent display device that can reduce power consumption in the fluorescent display device by eliminating or reducing the power consumption of filament electrodes and grid electrodes. It is.

In order to achieve such a target sound, the present invention heats the first filament electrode to the rated temperature in conjunction with the power switch of the fluorescent display device, and the other filament electrodes drive the plate electrode. Heating is performed to a rated temperature by an AND signal of a display signal and a digit selection signal for driving the grid, and will be explained in detail below using an example.

Figure 2 shows an embodiment 11 of the method for driving a fluorescent display device according to the present invention, in which n fluorescent display tubes 18 to 1n for displaying n-digit numbers or characters are provided. It is. In the figure, 58 is a preheating filament power source for preheating each filament electrode of the fluorescent display tubes 1b to 1n from the second digit to the first digit, and 5b is a heating filament power source for preheating. The sum of the voltage of the heating filament power source 5a and the heating filament power source 5b becomes the rated voltage of the filament. This preheating filament power supply 58 is a power supply with a voltage sufficiently lower than this rated voltage. 9a and 9b are fluorescent display tubes 1a to 1n
A grid driving transistor 10 is a group of n-1 flip-flops that each inverts "on" at each digit pulse of their digit pulse generator and maintains the on state until a clear signal is applied. 1
1 is a filament switch circuit for selecting the filament of the fluorescent display tubes 1b to 1n from the second digit onward; 12 is a clear signal terminal to which a clear signal for clearing the flip-flop circuit group 10t is given when updating the display; A digit pulse generator for selectively driving the fluorescent display tubes 11 to 1n, 14 a segment decoder, 15 a segment driver, 16a to tse resistors, IT a resistor, 18 Zener diodes, and 19a to 19n-1 20 is an or game), and 21b to 21m are AND gates.

Next, the operation of the method for driving the fluorescent display device having the above configuration will be explained. First, when the power switch (not shown) of the fluorescent display device is turned on, the filament electrode 2a of the fluorescent display tube 111 of the first digit matches the voltage of the preheating filament power supply 5a and the heating filament power supply σ-5b. Since a high voltage is applied, it is heated to the rated temperature. on the other hand,
The second to nth digit filament electrodes 2a to 2n are heated to a preheating temperature by a preheating filament power source 5a. Next, when a display instruction signal to the first digit is inputted by a keyboard switch (not shown) of the fluorescent display device,
Digit pulse generator 13 operates. Therefore, the first digit pulse output from the digit pulse generator 13 makes the shift grid driving transistor 9a conductive, and the grid electrode 3a is driven. On the other hand, since the characters or honorific information to be displayed are applied to the plate %i4m via the segment decoder 14 and segment driver 15, the fluorescent display tube 1 m F
(The desired number or character is displayed.

Next, when a display instruction signal is input to the second digit (by using a keyboard switch (not shown) to display characters at the 2V1 position), the digit pulse piegenerator 13 is activated and the 2411th character is displayed. Due to the pulse, the grid driving transistor 9b becomes conductive 9, and the grid electrode 3
b is driven. On the other hand, the character or numerical information to be displayed is passed through the segment decoder 14 and segment driver 15 to the second digit plate of the fluorescent display tube 1b.
At the same time as the display signal is applied to the segment driver 15, the display signal output from the segment driver 15 is applied to the ant game via the OR gate 20.
It is input to one input terminal of 21b to 21n. Therefore, since the digit selection signal output from the digit pulse generator 13 is input to the other input terminal of the AND gate 21b, the AND gate 21b receives the logical product t of these two signals, and its output signal is 7. Lipflop group 1
Enter 0.

Therefore, the flip-flop group 10 operates, and only the second digit filament switch (not shown) of the filament switch 110 becomes conductive due to its output signal.

Therefore, this first digit filament electrode 2b is heated at a rated voltage that is the sum of the voltage of the preheating filament temperature 5a and the voltage of the heating filament power source 5b. Therefore, since character or numerical information to be displayed is applied to the plate electrode 4b via the segment decoder 14 and the segment driver 15, the second digit fluorescent display tube 1
Predetermined characters or numbers are displayed in b.

Hereinafter, in the same manner, the digit pulse generator 13
The grid driving transistors 9c to 9n are sequentially turned on by the pulses from the 3rd digit to the (n-1) digit, thereby driving the desired fluorescent display tubes 1C to 1 and the grid electrodes 30 to 3n, and also driving the 7 lip-flop groups. 10 and the selected fluorescent display tube 1C-1 through the filament switch circuit 11.
n filament electrodes 2C to 2n can be heated.

Here, the tree flop group 10 is selected by the logical product of the χ selection signal and the display signal so that the filament electrode of the lit digit is heated to the rated value, and in the selected state, the display clear signal is sent to the clear terminal 12. It will remain in that state until it is input.

As mentioned above, since the lighting digits are selected, the filament electrode is not heated at the rated value in the non-lighting digits, and the grid signal for digit selection is the K11 selection pulse for all digits, regardless of whether they are lit or not. However, since the filament temperature has not reached the rated temperature, the grid current will naturally be very low. Therefore, both the filament electrode power consumption and the grid electrode power consumption in the non-lit digits are extremely low, and the segment electrode power consumption increases to zero in the non-lit digits. The power consumption of the color display tube becomes extremely low. i9. The reason why only the filament electrode in the first digit is always set to the rated heating temperature is because some characters are always displayed in the first digit, so if only the first digit is always heated at the rated temperature, , the switch circuit component for the first filament electrode can be omitted.

An example of a display pattern used in a fluorescent display tube is shown in FIGS. 3(f) and 3(b). 4I and Hall 3 (
In the case of a fluorescent display device having the display pattern shown in (v), unless a character display instruction signal is input, the first digit is ``0''.
A demonstration will be made. In addition, in a fluorescent display device with the display pattern shown in Fig. 3 (b) K, only the cursor 22 is displayed in the first digit when the character display signal is not scanned, and the first digit is always lit. It has become a state. Next, the non-lit digit filament! The pole has a pre-biasing force [Heating improves the rise rate of the filament electrode and speeds up the response speed.
For example, when the temperature is suddenly raised to the rated temperature from an unheated state, a rush current several times the rated current flows, so it is necessary to use a filament switch circuit 11 with a large capacity. is made possible with a small capacity switch.

However, the preheating may be provided as necessary, and may be omitted if the filament response speed and rush current are not a problem. Furthermore, in the above embodiments, a fluorescent display tube in which each digit is enclosed in an independent vacuum container was explained as an example, but a fluorescent display tube in which all digits are enclosed in -9 true containers is also applicable. Of course you can do the same. In addition, although it has been shown that the signals of all segment electrodes can be obtained from the signal tube, for example, if the display pattern shown in FIG. 3 (4) is to display only "0 to 9", It is sufficient to obtain the OR signal of only the segment signal lit in common in all display patterns as shown in FIG. ), even in the case of a display pattern, the OR signal of several segments lit in common to all display patterns, or if the cursor is not always used, only the cursor signal is sufficient. can also be used with a very small number of terminals. Further, although the first digit is counted from the right end, the present invention is not limited to this, and it goes without saying that the 11th character displayed in the fluorescent display device may be considered as the first digit.

In addition, although the above explanation assumes that the filament electrodes of each digit are driven independently, it is possible to drive the filament electrodes of each digit independently.
For example, an upper row of filament electrodes for 2 or 3 digits! !
Of course, it may also be driven by looking at the camera.

As explained in detail above, the original W! AK According to the method of driving a fluorescent display device, the power consumption of the fluorescent display device is reduced, the number of filament switch parts is reduced, and the capacitance of the filament switch parts is also reduced, so that the response speed can be improved. There is an effect that a fast fluorescent display can provide.

[Brief explanation of the drawing]

Figure 1 (A), Figure 1 Middle) and Figure 1 (C) are circuit diagrams showing a conventional method of driving a multi-digit fluorescent display tube, respectively.
The figure is a block diagram showing an embodiment of the method for driving a fluorescent display device according to the present invention.
Figure (b) is a diagram showing an example of the display pattern of FIG. 2, respectively. 1a ~1t1' ” ”Iytf display tube, 28~
2d...number filament electric fi, 3a~3d a @
* 11 Grid electric power supply, 4a to 4d...Plate electrode, 511.e Fist filament power supply, 5a...Filament electric supply for preheating, Eb...Filament power supply for heating, 6... Drive power supply, T...Common line, 8...Working filament electric switch, 9a and S
b-Φ Self-e grid driving transistor, 10...
Digit pulse, 11...Filament switch circuit, 12...Clear signal terminal, 13...Digit pulse generator, 14...Segment decoder, 15...Segment driver, 16@~16
e...Resistance, 1T60.・Resistance, 18...Tsete diode, 191~19nt @ -116
Diode, 2Q*a*・orgame), 21b~
21n...and gate, 22...cursor. Patent Applicant Ise Electronics Co., Ltd. Agent Masaki Yamakawa (1 person) ・'ri (4) Figure 3 (b) Rororo Kuchiguchi

Claims (1)

[Claims] (1) Fluorescent display tube t' consisting of a plurality of plate electrodes, a grid electrode commonly provided opposite to the i-poles of the plurality of plate electrodes, and a filament electrode provided opposite to the grid electrodes. In a multi-digit fluorescent display device in which a plurality of filament electrodes are arranged in the direction of the digits, the filament electrodes in the first digit are heated to the rated temperature in conjunction with the power switch of the fluorescent display device, and the filament electrodes in the other digits are heated. A method for driving a fluorescent carp display device V,', characterized in that the device is heated to a short-circuit temperature by an AND signal of a display signal for driving a plate electrode and a digit selection signal for driving a grid. 21. The method for driving a fluorescent display device according to claim 17J, wherein the filament electrodes other than the first digit filament electrode are heated at a preheating temperature lower than the rated temperature at all times.