JPS6047640B2 - alarm display device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an alarm display device using a liquid crystal panel, and more particularly to an alarm display device that has a simple configuration and performs divided display and flicker display at the time of an alarm.

Generally, when displaying an alarm by dividing the alarm into multiple sections, an alarm display as shown in FIG. 1 is used. This alarm indicator has partition plates 2a and 2b provided inside the case 1 to form a plurality of divided areas, and separate lamps 3a, 3b, and 3c are housed inside these areas and divided into separate areas. The structure is such that it can be displayed, and a glass or lens is attached to the entire front part of the case 1, and colored plates (not shown) are arranged in each divided area as necessary.
Although not shown, when an object in the process is normal, a lamp corresponding to that object is turned on, and when the object is abnormal, the lamp is displayed with a score.
Note that these alarm indicators are usually used in digital equipment such as computers, and the lighting and dosing of the lamps 3a are performed by a driver circuit. Therefore, in the alarm display device using the alarm display shown in FIG.
, 3b, 3c, when they turn on or blink, a large transient current or current consumption flows, so the drive circuit of the lamps 3a, 3b, etc. that are connected to digital devices such as computers (
(not shown) has no choice but to have a complicated configuration.

Furthermore, magnetic noise is generated from the transformer when a transient current flows, and this can cause digital circuits to malfunction. Further, in the case of divided display, lamps 3a, 3b, . . . are required as many as the number of divided areas, and when redundancy is provided, two lamps are required for one division, that is, twice as many lamps as the divided areas. In addition to this, there is the inconvenience that partition plates 2a and 2b must be provided to prevent light from leaking into adjacent areas. The present invention has been made in view of the above-mentioned circumstances, and provides an alarm display device that eliminates the blinking driving method of lamps, eliminates the generation of transient currents and magnetic noise, and also enables divided display without providing divided areas. We have something to offer.

That is, in the device of the present invention, a liquid crystal panel having a plurality of divided electrodes is arranged on the front surface of the lamp, and signals of different frequencies are applied to the electrodes so that the liquid crystal appears to be lit continuously or in dimming. .

An embodiment of the present invention will be described below with reference to the drawings. FIG. 2 is a diagram showing an example of an alarm indicator, in which one light source 12 (for example, a light bulb) is housed inside the case 11 without a partition plate, and a liquid crystal panel 13 is mounted on the front of the case 11. It is placed. As is well known, this liquid crystal panel 13 has two glass plates 13a, 13a'', and one of the glass plates 13a has an electrode 13b as shown in FIG.
For example, three divided electrodes 13c, 13C'', 13C'' are placed on one of the glasses 13a'', and the glass 13a, 13a'' has fluidity like a liquid and is optically conductive. encapsulates anisotropy. Furthermore, this liquid crystal panel 13 has electrodes 13b and 13c.
, 13C″, 13″, glass 13a, 13a″
polarizing plates 14a, 14b, which have a light color filter function;
14b'', 14b'''' are arranged.In the case of the above-mentioned alarm indicator, first, power is supplied to the light source 12 to keep it lit at all times.

In this state, the electrode 13b and any electrode 13b,
13b'', 13b'' is supplied with alternating current voltage. Then, the direction of the liquid crystal molecules changes and the amount of light emitted from the light source 12 changes, and this light passes through the polarizing plates 14a, 14b, 14b'', 14b'''' attached to both sides of the glass, and the liquid crystal panel 13. This alarm indicator displays as if the electrode 13b is lit.
, 13c, 13C'', 13C'' can be turned on continuously by applying alternating voltage to 13C''; if the alternating current voltage is suddenly cut off, the lights will go out; if a low frequency alternating voltage is applied, the lights will flicker and turn on and off. can be made.

For this reason, in the past, various problems were caused by transient current when the lamp blinked, but in the alarm display shown in Fig. 2, an alternating current of several volts is applied to the liquid crystal panel 13 without blinking the light source. Since control is performed by applying voltage, there is no transient current, and current consumption is small, so the drive circuit can be simplified and malfunctions of digital circuits can be eliminated. In particular, in the case where the alarm is driven by a microcomputer, the electrodes 13b, 13c,
If configured with semiconductor switches such as FETs, C-MO
It becomes possible to drive directly with S-1C. Also,
When performing split display, conventionally a partition plate is provided to prevent light from leaking into the adjacent split area, but with this device, split display can be performed without the need for a partition plate.

Next, an example of the alarm display device will be described with reference to FIG.

In the figure, 21H is a first AC power supply that generates a high frequency AC voltage, and 21L is a second AC power supply that generates a low frequency AC voltage.
One end is commonly connected to the electrode 13b of the liquid crystal panel 13,
In addition, the other ends of the power supplies 21H and 21L are FET analog switches 22Ha to 22Hc and 22L1 to 22L, respectively.
It is connected to electrodes 13b, 13c, 13C'', and 13C'' via. 23 is an analog switch 22Ha~22
This is a signal generator that generates a digital signal to control on/off the HC, 22L1 to 22L.

The operation of the apparatus shown in FIG. 4 will be explained below. First, when the process system is normal, a signal is output from the signal generator 22 to turn on the analog switches 22Ha to 22HC. As a result, the high frequency AC voltage generated from the first AC power supply 21H is transferred to the analog switches 22Ha to 22Hc.
Power supplies 13b, 13c, 13C'' for the liquid crystal panel 13 through
, 13C'''', and the liquid crystal panel 13 is continuously lit and displayed. Note that depending on the abnormal location, the electrodes 13c, 1
It goes without saying that 3C'' and 13C'' can be selected arbitrarily. Analog switch 22Ha~22Hc, 22L1~
When all of 22LC are off, electrodes 13b, 13c,
Power supplies 21H and 21L are not applied to 13C'' and 13C''.

Next, if there is an abnormality in the process system, the signal generator 23 outputs a signal to turn off the analog switches 22Ha to 22HC and turn on some or all of the analog switches 22La to 22LC. 21L passes through analog switches 22La to 22L to electrodes 13b and 13.
c, 13C″, 13C″, and the second AC power supply 21
The liquid crystal panel 13 creates a flickering state by the low frequency AC voltage L.

- This liquid crystal panel 13 will perform a blinking display. If another low-frequency AC power source is provided for flicker, it is possible to display alarms such as a first alarm and a second alarm depending on the degree of severity. Next, FIG. 5 is a diagram showing another example of an alarm indicator, which uses a flat light source such as a fluorescent lamp instead of a light bulb, and further includes a large number of electrodes 13b, 13c, 13C″, ・・
This is a multi-point alarm indicator by connecting multiple units.

Therefore, in this case as well, the fluorescent light source 11 is kept on at all times as in FIG. 2, and there is no need to provide partition plates or the like for the divided areas. As described in detail above, according to the present invention, AC voltage is supplied only to the electrodes of the liquid crystal panel when power is supplied to the light source and the light source is continuously lit. As a result, malfunctions of the digital circuit can be prevented, and current consumption is reduced, making it possible to simplify the drive circuit.

Further, even when displaying a plurality of divided areas, the electrodes of the liquid crystal panel can be divided and provided, and there is no need to arrange partition plates or to have a structure in which lamps are housed in each divided area. Furthermore, if two lamps are connected in parallel and housed in a case, one lamp can be checked with the other lamp without the need for a particular lamp check circuit. Furthermore, with the configuration of the device of the present invention, a normal fluorescent lamp can be used, which not only saves power but also allows the device to function as a multi-point alarm.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the schematic configuration of a conventional alarm display device;
The figure is a schematic configuration diagram of an alarm indicator applied to the device according to the present invention, Figure 3 is a diagram showing the electrode arrangement of the liquid crystal panel shown in Figure 2, and Figure 4 is a configuration showing one embodiment of the alarm indicator. Figure, 5th
The figure is a perspective view showing another example of the alarm indicator. 12... Light source, 13... Liquid crystal panel,
13a, 13a''...Glass, 13b, 13b
"13c, 13C"...Electrode, 14a, 14b,
14b''...Polarizing plate, 21H, 21L...
・・AC power supply, 22Ha~2"Hc, 22La~22L
c...Analog switch, 23...Signal generator.

Claims (1)

[Scope of Claims] 1. An alarm display having a light source inside and disposing a liquid crystal panel with electrodes divided into a plurality of parts on the front surface, and first and second alarm indicators that generate high-frequency and low-frequency alternating current voltages. an AC power source, and a signal that generates a signal for supplying the high frequency AC voltage of the first AC power source to the electrode during normal times and for causing the low frequency AC voltage of the second AC power source to be supplied to the electrodes during abnormal times. An alarm display device comprising: a generator. 2. The alarm display device according to claim 1, wherein two light sources are connected in parallel so that one light source performs a heat insulation check on the other light source. 3. The alarm display device according to claim 1, wherein the second AC power source is two AC power sources that generate different low-frequency AC voltages, and is selected and used depending on the severity of the abnormality.