JPH0310318B2 - - Google Patents

Description

[Detailed Description of the Invention] (a) Technical Field of the Invention The present invention relates to a segment numerical display device, particularly in devices that always display a negative sign, such as decibel display, water level display, and freezer compartment temperature display. In particular, the present invention relates to a segment numeric display device that automatically displays and erases a minus sign added to numerical data in conjunction with erasing the numerical data.

(b) Prior art and problems When a minus sign is displayed in a conventional 7-segment numerical data display device, points are deducted regardless of the numerical data associated with it. Therefore, when data is turned off all at once, the numbers disappear, but the negative sign remains. FIG. 1 shows an example of the prior art, in which the g segment of a minus sign display 1 is forcibly connected to a positive power source, and the g segment is lit to display a minus sign. In this case, since there is no linkage with numeric data, the minus sign remains even if the digits are turned off on the segment numeric displays 2 and 3, making the display difficult to see.

Note that 2a and 3a are display drivers.

(c) Purpose of the Invention The purpose of the present invention is to constantly monitor data, and when the data display is completely erased, the minus sign is also automatically erased, thereby eliminating the inconvenience that only the minus sign remains when the data is erased. It is to be resolved.

(d) Structure of the Invention According to the present invention, the above object is to provide a numeric display device that displays a minus sign at the same time as the digits in a plurality of segment display devices that display digits using seven segments. The display driver includes a plurality of segment displays, a segment display for displaying a minus sign, and a display driver that drives the segment display for displaying the plurality of numbers, and drives the segment display for the plurality of numbers. Among the outputs corresponding to segments of at least the least significant digit of the display driver in the display driver, the OR of the two outputs corresponding to the segment that can always be output when displaying numbers is taken, and the output of the segment display for displaying the minus sign is calculated. Connect to the segment that displays the minus sign,
This is achieved by a segment display device characterized in that a segment display signal is always output when there is a numeric input in a display driver.

(e) Examples of the invention The present invention will be explained below based on examples.

To explain the present invention using the drawings, FIG. 2 shows an embodiment of the present invention, in which 1 is a minus sign display device and its g segment is used to display a minus sign. 5 is a number point reduction state detection device. Since the upper digits of numerical data may be erased by zero suppression, the numeral point reduction state detection device 5 uses the numeric display driver 3a of the lowest digit.
connected to a specific segment of In the lowest digit numeric display 3, the segment corresponding to the lowest digit numeric display driver 3a that is in the on state lights up. For example, when the a segment driver output of the least significant digit numeric display driver 3 is turned on and becomes a positive voltage, current flows into the a segment of the major and least significant digit numeric display 4, causing the a segment to light up. In this state, the output of the a segment driver of the least significant digit numeric display driver 3a passes through the numeric point decrement state detection device 5 and current flows into the g segment of the minus sign display 1, causing the g segment to display a minus sign. indicate. On the other hand, when the least significant digit numeric display is off, a of the least significant digit numeric display driver 3a,
Both the c-segment drivers are turned off, and no current flows into the a and c segments of the least significant digit numeric display 3a, so neither the a nor c segments are displayed.
That is, the fact that the a and c segments are in the off state indicates that the least significant digit numeric display 3 is in the off state. At this time, no current flows from the a and c segment drivers of the lowest digit numeric display driver 3a to the g segment of the minus sign display 1 via the numeric point decrement state detection device 5, so the g segment does not light up. The minus sign turns off. Third
The figure shows another embodiment of the invention.

In the case of FIG. 3, the display state of all digits is monitored. For this reason, a numerical point deduction state detection device 5a is further added.

This embodiment is effective in the following cases. That is, when numerical data is transmitted and displayed for each digit, a parity check is performed on the receiving side, and if it is correct, it is displayed, and if it is incorrect, it is not displayed and a retransmission request is sent back. At this time, if a parity error occurs only in the numerical data of the least significant digit, but the other digits are correct, the 〓1'' sign will not be displayed in the example in Figure 2.However, in the example in Figure 3, 〓 1” sign is displayed.

(f) Effects of the Invention According to the present invention, when numerical data is erased, the minus sign is automatically erased in conjunction with it, so there is no unnecessary display that only the minus sign remains lit when data is erased. Since there is no need to separately apply a control signal from the outside to subtract the +/- sign, the circuit configuration can be simplified.

[Brief explanation of drawings]

Figure 1 is a conventional numerical data display configuration diagram, Figure 2
FIG. 3 is a diagram showing a segment numeral display device of the present invention. In the figure, 1 is a minus sign indicator, 5, 5
a indicates a number point reduction state detection device.

Claims (1)

[Scope of Claims] 1. In a numeric display device that displays a minus sign at the same time as the digits in a plurality of segment displays that display numbers using seven segments, the plurality of segment displays for displaying numbers, and a minus sign are provided. The display driver includes the segment display for displaying a code and the segment display for displaying the plurality of numbers, and at least the least significant digit of the display driver for driving the segment display for the plurality of numbers. Among the segment-compatible outputs of the display driver, take the OR of the two outputs corresponding to the segment that can always output when displaying numbers, and connect it to the segment that displays the minus sign of the segment display for minus sign display. A segment display device characterized in that a segment display signal is always output when there is a numerical input in a display driver.