JP2716594B2 - Brightness adjustment circuit for fluorescent display tube and brightness adjustment method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a luminance adjusting circuit for a fluorescent display tube.

[0002]

2. Description of the Related Art FIG. 5 shows a conventional luminance adjusting circuit for a fluorescent display tube.
It is. In the figure, 1 is a matrix of red, green and blue phosphors.
The fluorescent display tubes arranged in a box have a constant high voltage applied to them.
Anode 3 is a shield electrode for controlling the amount of emitted electrons, 4
Is an X grid (scanning electrode) to which a scanning signal is applied, and 5 is
Y grid (data
, 6 is a filament that emits electrons, 7 is scanning
A driving circuit for supplying a signal to the X grid 4, and 8 is turned on / off.
A driving circuit for supplying a lamp signal to the Y grid 5;
X-grid controller to make the signal
A Y-grid controller for making a signal
₁, R_Two12 is a transistor, V_DIs
Drive voltage, V_HIs the high voltage applied to the anode 2, V_KIscut
OFF voltage, V_fIsFilament voltageIt is. Next,
explain about. The fluorescent display tube 1 is released from the filament 6.
The emitted electrons are accelerated by X and Y grids 4 and 5.
It emits light by colliding with the anode 2 and has X, Y grids 4,
5 by drive circuits 7 and 8 and controllers 9 and 10.
You can get any display by controlling
You. X, YgridThe drive circuits 7, 8 of 4, 5 are respectively
Drive voltage V according to the control signal of_DSwitchon
And supply it to the X and Y grids. Resistance 11 and Transient
The drive voltage V_DPressure
The shield electrode 3 is connected to the shield electrode drive voltage (hereinafter V_S
V)_s= V_D× R_Two/ (R₁+ R_Two). Here, the brightness of the fluorescent display tube 1 is
6 and X and Y grids 4 and 5, shield electrode 3 and positive
Because it depends on the voltage between pole 2X, Y grid
VD supplied to 4, 4 and high voltage V applied to anode 2_H
Is constant, the seal supplied to the shield electrode 3 is
Electrode drive voltage V_SOf the fluorescent display tube 1 by changing the value of
Adjust the brightness.

[0003]

Since the conventional luminance adjusting circuit for a fluorescent display tube is constructed as described above, the shield electrode driving voltage V _S supplied to the shield electrode of one fluorescent display tube is arbitrary. There is a problem that the brightness cannot be adjusted for each color in the tube because the voltage value is fixed. SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-described problems, and has as its object to obtain an apparatus that enables luminance adjustment for each color in a fluorescent display tube. Also, such a brightness adjustment method
It presents the law.

[0004]

According to a first aspect of the present invention, there is provided a brightness adjusting circuit for a fluorescent display tube, comprising a shield electrode drive voltage adjusting circuit having the same number of fluorescent electrode colors as the controller, and controlling the voltage adjusting circuit. Is a circuit in which the shield electrode drive voltage is switched in a time-division manner to provide a luminance adjustment circuit for each color. According to a second aspect of the present invention, in the luminance adjusting circuit for a fluorescent display tube, the microcomputer for controlling the driving circuit reads the set luminance data written in the nonvolatile memory to the D / A converter based on the luminance data. Switch the generated shield electrode drive voltage in a time-sharing manner,
This is a luminance adjustment circuit for each color.

[0005]

According to the first aspect of the present invention, the controller of the luminance adjusting circuit for the fluorescent display tube can adjust the shield electrode driving voltage for each color by switching each voltage adjusting circuit in a time division manner. According to the second aspect of the present invention, the microcomputer for controlling the driving circuit of the luminance adjusting circuit of the fluorescent display tube can control and adjust the shield electrode driving voltage for each color by the luminance data written in the memory.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the first invention will be described below with reference to the drawings. FIG. 1 is a circuit diagram of a luminance adjusting circuit for a fluorescent display tube according to the first invention. In the figure, 13R is a switch circuit of a voltage adjustment circuit for R (red), 13G is a switch circuit for G (green), 13B is a switch circuit for B (blue), 14 is a controller, 15 is a voltage adjustment circuit for R, 16 Is a voltage adjustment circuit for G, 17 is a voltage adjustment circuit for B, and the other devices (reference numerals 1 to 10) are the same as in the conventional example.

FIG. 2 is a diagram showing a matrix structure of the X grid 4 and the Y grid 5 of the fluorescent display tube of the present invention. From the figure, R, G, and B are two-dimensional pixel corresponding areas for each color on the phosphor screen, X
G1 to XG8 indicate eight pixel grid corresponding matrix rows of the X grid 4, and YG1 to YG8 indicate eight pixel grid corresponding matrix columns of the Y grid 5. FIG. 3 is a diagram showing the relationship between the waveform, timing, and display color of a signal applied to each electrode of the fluorescent display tube 1 of the present invention. Each XG1 of X grid 4
-XG8 time-division scanning signal waveforms applied at the timing of, Y grid 5 of each of YG1-YG8 in time on / off signal waveform applied at the timing of the _division, V _R, V _B,
V _G shows shield electrode applied voltage waveform, R, B, G is a fluorescent display color.

Next, the operation will be described. If the fluorescent display tube 1 from 1 This R, G, comprises three voltage regulating circuit 15, 16, and 17 for each of B color, switching circuits 13R each voltage regulating circuit by applying a driving voltage V _D min, 13G, 13B
There shield electrode driving voltage for each color to the shield electrode 3 when the _{ON (V R, V G,} V B) for supplying, although this voltage value is not a fixed value V _S of the conventional example. Switch circuit 1
3R, 13G, 13B are turned on by the controller 14
/ OFF control, and one of three drive voltages V _R , V _G , and V _B is supplied to the shield electrode 3. The controller 14 switches the outputs of the voltage adjusting circuits 15, 16 and 17 in a time-division manner. Since the luminance of the fluorescent display tube 1 is different for each color even when the driving voltage V _S is constant, it is switched for each color in this manner. By applying different voltage values to the shield electrode 3, it is possible to adjust the luminance for each color.

2 and 3, a signal waveform applied to each electrode of the fluorescent display tube 1 and a time division switching timing of luminance adjustment for each display color will be described. As shown in FIG.
Each of XG1-XG8 of the grid 4 (here, the number of grids is assumed to be eight for the sake of description), to which each of the YG1-YG8 of the Y grid 5 is applied a scanning signal having a duty of 1/8.
To the pixel at the intersection of the X and Y grids are applied in a time-division manner for each color. In this case, the odd columns YG1,
YG3, YG5, YG7 and even rows YG2, YG4, Y
G6, YG8 the time by V _R, V _G, V driving voltage controller 14 _B in the lighting pulse (positive) Off pulse (negative) is applied, the shield electrode 3 as a group column for each display color Applied to split. Now, assuming that the first R (red) point in the display color string is started from FIG. 3, the controller 14 selects R (red) luminance adjustment, turns on the switch circuit 13R of the voltage adjustment circuit 15, and sets the shield electrode 3 supplying a shield electrode driving voltage V _R to. At this point, the X grid 4 is scanning the XG8 area,
In the grid 5, the odd columns are at the time of applying the light-off signal, and the even columns are at the time of applying the light-up signal. Therefore, from the matrix structure diagram of FIG. 2, XG8 rows and Y even columns, YG2, YG4, YG6, YG8
R (red) luminance adjustment is performed in the intersection area of. Moving to the next operation, the controller 14 selects B (blue),
ON voltage adjusting circuit 17 supplies a shield electrode driving voltage V _B to the shield electrode 3, X grid 4 is an in scanning XG1, when Y grid 5 is an odd number column lighting signal applied, even columns and off Become. From the matrix of FIG. 2, XG
B at the intersection area of one row and YG1, YG3, YG5, YG7
The (blue) luminance adjustment is performed.

As described above, the brightness adjustment for each color is performed by the controller 14 in conjunction with the switching timings of the X grid controller 9 and the Y grid controller 10 of the fluorescent display tube 1 and the voltage adjustment circuits 15, 16,.
By processing the 17 switching timings in a time-sharing manner, it is possible to adjust the luminance for each color.

Next, an embodiment of the second invention will be described with reference to the drawings. FIG. 4 is a circuit diagram of a luminance adjusting circuit of the fluorescent display tube according to the second invention. In the figure, 20 is a drive circuit control computer, 21 is a D / A converter, 22 is a voltage conversion circuit,
Reference numeral 23 denotes a nonvolatile memory, and other devices and reference numerals are the same as those of the first embodiment. Next, the operation will be described. In the fluorescent display tube 1 shown in FIG. 4, a D / A converter 21 and a voltage conversion circuit 22 are connected to the shield electrode 3. The non-volatile memory 23 stores set brightness data for adjusting the brightness of the fluorescent display tube 1. This luminance data is data that detects the luminance of each color of the fluorescent display tube 1 and makes the luminance constant for each color. Microcomputer 20
When the power is turned on, the D / A converter reads luminance data from the non-volatile memory 23, writes the luminance data in the RAM in the microcomputer 20, and outputs the written luminance data to the D / A converter 21 according to the luminance of the display color. 21 generates a voltage corresponding to the luminance data, supplies the voltage to the voltage conversion circuit 22, and applies a shield electrode driving voltage corresponding to the luminance data to the shield electrode 3 in a time-division manner for each color, thereby adjusting the luminance of each color. do.

The X, Y matrix structure diagram of FIG.
Since the signal timing chart of FIG. 3 is the same as that of the second invention, the same parts as those of the first invention are omitted, and the time division of the brightness adjustment of each display color in the second invention is omitted. The switching timing will be described. Now, assuming that the first R (red) of the display color string is started from FIG. 3, the microcomputer 20 selects the luminance adjustment of R (red) from the luminance data, and the D / A converter 21 responds to the luminance R. and it outputs the data, D / a converter 21 is applied to the shield electrode through the voltage conversion circuit 22 generates a V _R corresponding to the luminance data. At this time, the X grid 4 is scanning the XG 8, and the Y grid 5 is the odd column, which corresponds to the light-off signal, and the even column, which corresponds to the light-up signal. Therefore, in the matrix of FIG. R (red) luminance adjustment is performed in the intersection area of. At the next time point, the microcomputer 20 selects B (blue),
When supplying a drive voltage V _B to the shield electrode 3 in the same manner, X grid 4 is being scanned XG1, Y grid 5 during an odd column lighting signal and the even-numbered columns becomes unlit signal.
Accordingly, from FIG. 2, the XG1 row and the YG1, YG3, YG5, Y
The brightness adjustment of B (blue) is performed in the intersection area of the G7 column.

As described above, the brightness adjustment for each color is performed by the microcomputer 20 by using the brightness data in the RAM and the X data.
Grid controller 9 and Y grid controller 10
Is controlled in a time-sharing manner, and a drive voltage corresponding to each color is applied to the shield electrode 3, so that the brightness of each color can be automatically adjusted.

Since an actual display device is composed of N fluorescent display tubes, an N-stage voltage adjustment circuit block is used in the first invention, and an N-stage D / A is used in the second invention. A converter and a voltage conversion circuit are provided for adjustment.

[0015]

As described above, according to the first aspect of the present invention, the voltage adjusting circuits for the fluorescent display tube shield electrode driving voltage are configured so as to have the same number as the colors of the phosphors. There is an effect that the luminance can be easily adjusted.
According to the second and third aspects of the present invention, the brightness adjustment of the fluorescent display tube is configured such that preset brightness data is stored in a memory, and a microcomputer controls a shield electrode driving voltage according to the brightness data. Therefore, there is an effect that finer and more accurate automatic brightness adjustment for each color can be performed.

[Brief description of the drawings]

FIG. 1 is a luminance adjustment circuit of a fluorescent display tube according to an embodiment of the first invention.

FIG. 2 is a diagram showing a matrix structure of an X grid and a Y grid.

FIG. 3 is a diagram showing the relationship between the waveforms of signals applied to the respective electrodes of the fluorescent display tube, timing, and display colors.

FIG. 4 is a luminance adjustment circuit of a fluorescent display tube according to one embodiment of the second invention.

FIG. 5 is a circuit diagram of a luminance adjusting circuit of a conventional fluorescent display tube.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fluorescent display tube 2 Anode 3 Shield electrode 4 X grid 5 Y grid 6 Filament 14 Controller 15 Voltage adjustment circuit for R 16 Voltage adjustment circuit for G 17 Voltage adjustment circuit for B 20 Drive circuit control microcomputer 21 D / A converter 23 Non-volatile In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (3)

(57) [Claims] An anode to which a phosphor of a plurality of colors is applied and to which a high voltage is applied; a scanning electrode for accelerating electrons emitted from a filament toward the anode to control light emission of an arbitrary color of the phosphor; In a fluorescent display tube provided with a grid electrode having a matrix structure composed of data electrodes and a shield electrode for controlling the amount of emitted electrons, a voltage adjusting circuit for driving the same number of shield electrodes as the color of the phosphor; Of the voltage adjustment circuits for
A brightness adjustment device for a fluorescent display tube, comprising: a sketch circuit connected to a field electrode; and a controller for switching the sketch circuit in a time-division manner. 2. An anode to which a phosphor of a plurality of colors is applied and to which a high voltage is applied, a scanning electrode for accelerating electrons emitted from the filament toward the anode and controlling light emission of an arbitrary color of the phosphor, and In a fluorescent display tube provided with a grid electrode having a matrix structure composed of data electrodes and a shield electrode for controlling the amount of emitted electrons, a nonvolatile memory in which set luminance data corresponding to the color of the phosphor is written. And the above
D / A converter that supplies arbitrary voltage to the ground electrode
If, reads the setting luminance data corresponding to the color to be displayed, and Ma <br/> Lee black computers to switch generated when the upper Symbol shield electrode driving voltage divided to the D / A converter based on the luminance data A brightness adjusting device for a fluorescent display tube, comprising: 3. A phosphor of a plurality of colors is applied and a high voltage is applied.
Anode, and the electrons emitted from the filament
To control the emission of any color of the phosphor
Of a matrix structure consisting of scanning electrodes and data electrodes
Grid electrode and shield electrode to control the amount of emitted electrons
Brightness adjustment method for adjusting the brightness of a fluorescent display tube equipped with
And the brightness data corresponding to the color to be displayed in advance.
The first procedure for storing in the memory the
A second procedure for reading the corresponding luminance data from the memory;
A luminance signal is given to the D / A converter by giving the luminance data.
Third procedure for sending the scan electrode to the shield electrode,
The second and third procedures are repeated in synchronization with the scanning of the data electrode.
Brightness of the fluorescent display tube, including a fourth procedure
Adjustment method.