JPH0483288A - Fluorescent display device - Google Patents

Abstract

PURPOSE:To attain the utilization of an efficient driver output circuit by serially inputting all grid data and all anode data to a driver. CONSTITUTION:Pattern data 9 from a character generator 2 are converted into serial data by a data selector included in a timing control part 3 and the serial data are inputted to a driver shift register part 4. Scanning data 12 from a microcomputer 1 are inputted to a shift register in the control part 3 by a scanning clock 11 and converted into serial data 15 by the data selector and the data 15 are inputted to the register part 4 by a data clock 13. After completing all the input of the pattern data 9 and the scanning data 12, these data are latched by a latch signal 14 and high voltage data 17, 18 are supplied from a driver high voltage output part 5 to the anode and the grid of a fluorescent display tube 6. Consequently, the driver output circuit can be efficiently used.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a fluorescent display device.

[Conventional technology]

Conventionally, this type of fluorescent display device, as shown in the block diagram of Figure 3, has a filament that emits thermionic electrons, a grid that sequentially selects digits, and an anode that is not coated with phosphor, all sealed in a vacuum container. It has a fluorescent display tube 6, a grid driver that sequentially scans the grid of the fluorescent display tube 6, and an anode driver that supplies pattern data to the anodes corresponding to the scanned grids. It also has a microcomputer 1 that performs interface control with external systems, memory and editing of display data, and generation of various timings for dynamically driving the fluorescent display tube 6. Upon receiving the address data 10 from the microcomputer 1, the character generator 2 inputs display pattern data 9 of 5×7 dots to the shift register and latch section 36 of the anode driver by the data clock 41, completing the data input of 35 dots. At this point in time, it is latched by the data latch signal 42, and an anode high voltage output 45 is supplied from the high voltage output section 37 to the anode of the fluorescent display tube 6. or,
The scan data 40 is supplied from the microcomputer 1 to the shift register section 38 of the grid driver, and the scan data 40 is supplied to the shift register section 38 of the grid driver by the scan clock 43 from the timing control section 35.
is input. In response to the output 46 of the shift register, a grid high voltage output 47 is supplied from the high voltage output section 39 of the grid driver so that the grid of the fluorescent display tube 6 is sequentially and selectively scanned. In this way, by applying a positive potential to the anode and the grid with respect to the potential of the filament of the fluorescent display tube, the anode corresponding to the grid lights up, and by sequentially scanning the grid, the corresponding anode of all the grids is illuminated as desired. The pattern will be displayed dynamically.

[Problem to be solved by the invention]

This conventional fluorescent display required an anode driver and a grid driver, respectively. The standard number of driver output circuits is 20.32.40.64 bits, but for example, in the case of a 12 digit x 2 line display and a 5 x 7 dot matrix, the number of output circuits is 24. If the number of anodes is 35 and the anode driver uses 40 bits and the grid driver uses 32 bits, an optimal driver configuration will be obtained. but,
The anode driver has 5 bits and the grid driver has 8 bits left over. This resulted in an increase in costs. Further, a driver with a small number of output circuits has a high unit price per bit, which also increases the cost.

[Means to solve the problem]

The present invention provides a fluorescent display tube equipped with a grid for selecting each digit of a filament cathode that emits thermoelectrons in a vacuum container, and a pattern display section consisting of a plurality of anodes coated with phosphor, and a time-sharing method for displaying the grid. a driver that sequentially scans the digits of the grid and supplies high-voltage pattern data to the anode in response to scanning of grid digits; and a microprocessor that controls the driver; means for converting anode data from a character generator that generates a character generator into serial data; and means for accumulating scan data from the microprocessor in synchronization with a scan clock and then converting the scan data into serial data. The anode data and scanning data converted into serial data are input to the shift register section of the driver consisting of a shift register, a latch, and a high voltage output section, and then latched and sent from the high voltage output section to the grid of the fluorescent display tube. and supplying high voltage data to the anode.

Further, the present invention includes means for detecting whether the scan data converted to serial data changes periodically,
The present invention is characterized in that the driver output is disabled when the scan data does not change for a period longer than a predetermined period.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram of one embodiment of the present invention. In response to the address data 8 from the microcomputer 1, the 5x7 dot pattern data 9 from the character generator 2 is converted into serial data by the data selector inside the timing control unit 3 every 7 bits, and then sent to the driver. 5 to shift register section 4
It is entered in batches. Further, scan data 12 from the microcomputer 1 is input to the shift register of the timing control unit 3 by the scan clock 11, the output of the shift register is converted to serial data 15 by the data selector, and the data clock 13 converts the scan data 12 to the shift register of the timing control unit 3. 4 is input. When all input of pattern data (3 rabbits) and 24 bits of scanning data is completed, the data is latched by the latch signal 14, and high voltage data 17 and 18 are supplied from the high voltage output section 5 of the driver to the anode grid of the fluorescent display tube 6. Then, the desired pattern will be displayed on the display section of the anode corresponding to the selected grid.

FIG. 2 shows a timing control circuit 3 according to the present invention.
FIG. The display pattern data 9 output from the character generator 2 is input to the 7-bit data input section 27.
is input to the data selector 22 from. At this time, the output of the hexadecimal counter is inputted from the hexadecimal power counter input section 30 and outputted from the shift register Y as serial data.
It is input to A1 of the human data selector 26. Further, at this time, the select signal 32 is set so that the input data of A1 is output from Yl of the data selector 26. In this way, all of the 7 bits x 5 data is output from the data output section 31 of the data selector 26 and input to the data input of the shift register 4 of the driver shown in FIG. Next, scan data 1 from the microcomputer 1
2 is from the scan data input section 28 to A of the shift register 23.
The scan clock 11 is input to the scan clock input section 29 and shifted by the scan clock 11 . At this time, only one of the 24 data outputs of the shift register 23 is at the "H" level and the others are at the "L" level.The 24-base counter output from the 24-base counter input section 34 is output from the data selector 24. 25, the 24 scan data are serially converted and output from the Y output of the data selector 25 to the B1 output of the data selector 26. At this time, the select signal 32 is set so that the B1 output is output as is to the Y1 output. Therefore, all 24 scan data are inputted from the data output section 31 of the data selector 26 to the data input of the shift register 4 of the driver shown in FIG.

All anode data and scan data are now input to the shift register 4 of FIG. 1 and latched. Further, high voltage data is supplied from the high voltage output section 5 to the anode and grid of the fluorescent display tube 6.

Therefore, since the anode is 35 bits and the grid is 24 bits, a fluorescent display tube can be driven by using a driver with a total of 59 bits of output circuits, but generally one driver with 64 circuits is used. .

Therefore, 5 circuits out of 64 circuits are unused, but when compared with the conventional example, in the conventional example, 13 circuits are unused, so the cost can be reduced by this amount. Further, the serial scan data 20 from the timing control section 3 in FIG. 1 (corresponding to the serial scan data output section 33 in FIG. 2) is input to the pulse detection circuit 7, and the serial scan data 20 does not change for a certain period of time or more. In this case, the high voltage specific force of the driver can be forcibly turned off by the disable signal 21. Therefore, if some kind of malfunction occurs and the scanning data becomes abnormal, the high voltage output of the driver is always on and the grid of the fluorescent display tube is turned off. can prevent damage to the fluorescent display tube.

〔Effect of the invention〕

As explained above, in the present invention, by serially inputting all grid data and all anode data to the driver, it is possible to use an efficient output circuit of the driver, and cost reduction is possible. Furthermore, it is possible to reduce the number of drivers used, and a reduction in man-hours and an improvement in reliability can be expected. Further, in the event that a problem occurs in which voltage is constantly supplied to the grid of the fluorescent display tube, the high voltage output of the driver can be turned off to protect the fluorescent display tube.

[Brief explanation of the drawing]

FIG. 1 shows a block diamond ram according to an embodiment of the present invention;
FIG. 2 is a circuit diagram of a part of the timing control section shown in FIG. 1, and FIG. 3 is a block diagram of a conventional example. DESCRIPTION OF SYMBOLS 1... Microcomputer, 2... Character generator, 3... Timing control section (present invention), 4... Shift register section of driver, 5...
High voltage output section of driver, 6... fluorescent display tube, 7...
Pulse detection circuit, 8, 10...address data, 9.
...Display pattern data, 11...Scanning clock, 1
2...Scanning data, 13...Data clock, 14
... Latch signal, 15... Serial data, 16.
...Shift register output, 1.7.18...High voltage data, 19...Interface signal, 20...Serial scanning data, 21...Disable signal, 2
2,24゜25.26...Data selector, 23...
・Shift register, 27...7 bit data input section,
28... Scanning data input section, 29... Scanning clock input section, 30... Heptadary power counter input section, 31... Data output section, 32... Select signal, 33... Serial scanning Data output section, 34... 24-ary power counter input section, 35... Timing control section (conventional), 3
6... Shift register section of anode driver, 37...
High voltage output section of anode driver, 38... Shift register section of grid driver, 39... High voltage output section of grid driver, 40... Scanning data, 41... Data clock (anode), 42... Data latch signal, 43
...Scanning clock, 44...Anode shift register output, 45...Anode high voltage output, 46...Grid shift register output, 47...Grid high voltage output.

Claims (1)

[Claims] 1. A filament cathode that emits thermoelectrons into a vacuum container;
A fluorescent display tube includes a grid for selecting each digit and a pattern display section consisting of a plurality of anodes coated with phosphor; a driver for supplying high-voltage pattern data to a fluorescent display device, and a microprocessor for controlling the driver, and means for converting anode data from the microprocessor or a character generator that generates pattern data into serial data. and means for accumulating scan data from the microprocessor in synchronization with a scan clock and then converting the scan data into serial data, the anode data and scan data converted to serial data being transferred to a shift register. A fluorescent display device, characterized in that the high voltage data is inputted to a shift register section of the driver comprising a latch and a high voltage output section, and then latched, and the high voltage data is supplied from the high voltage output section to the grid and anode of the fluorescent display tube. 2. It has means for detecting whether the scan data converted to serial data changes periodically, and if the scan data does not change for a period longer than a predetermined period, it is determined that the driver output has been disabled. The fluorescent display device according to claim 1, characterized in that: