JPH0785387A - Display device and gas alarm equipment - Google Patents

Abstract

PURPOSE:To obtain a display device whereby current quantity required as a whole display device is reduced and minituarization and power saving are easily attained and to obtain a gas alarm equipment with such a characteristic. CONSTITUTION:Plural light emitting display equipments LED 1, LED 2, LED 3 and LED 4 and a driving circuit ICI respectively controlling the light emitting driving and driving stop of the plural light emitting display equipments in accordance with an input signal level are provided and whole wave rectification obtained from a DC circuit 5 with a whole wave recttifying circuit BD is adopted as the power source of the driving circuit ICI in the display device. In the device, the plural light emitting display equipments LED 1-LED 4 are divided into two groups so as to constitute a first light emitting display equipment group and the second light emitting display group and a pair of half wave rectifying circuit C1 and C2 respectively supplying half-wave rectificatin which is obtained by respectively half-wave-rectifying DC obtained from a pair of FC input parts O as against the whole wave rectifying circuit BD to the first and second light emitting display equipment groups are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a plurality of light emitting displays,
A drive circuit for separately controlling light emission drive and drive stop of the plurality of light emitting displays according to the level of an input signal is provided, and full-wave rectification obtained from an AC circuit via a full-wave rectification circuit is used as a power source of the drive circuit. The present invention relates to a display device and a gas alarm device that employs the display device having such a configuration.

[0002]

2. Description of the Related Art Various display devices for displaying an input signal level by light emission have been developed, but at present, for the purpose of easy viewing and subdivision of level display, the luminous intensity is increased in order to make the display clear. Attempts have been made to increase the number of display devices. FIG. 3 shows a circuit of a conventional display device (circuit within a broken line in the figure) 100 and a gas alarm device (the circuit of the whole diagram) 101 which employs the display device 100. This circuit includes a detection unit 103 for detection and buzzer operation.
And a display unit 104 which is the display device 100, and operates by receiving electric power from an AC power supply 105.
That is, the detection unit 103 includes a transformer T, a detection sensor S,
A comparator IC2 and a buzzer B are provided, and when the output of the detection sensor S is higher than a set value, the buzzer B operates and issues an alarm. Further, the output from the detection sensor S is sent to the level meter integrated circuit IC1 as a drive circuit in the display unit 104, and is used for level display. on the other hand,
The configuration of the display unit 104 is such that the light emitting diodes LED1 to LED4, which are a plurality of light emitting indicators, are driven to emit light and stopped in accordance with the level of the input signal input to the level meter integrated circuit IC1. The level of the input signal is displayed. The operation configuration will be described in more detail. This circuit uses a bridge diode BD, which is a full-wave rectifier circuit, for converting an alternating current of a predetermined voltage obtained by the transformer T.
The full-wave rectification is performed as a power source. This power source is a power source for the level meter integrated circuit IC1, and is also used as a power source for lighting the light emitting diodes LED1 to LED4. Since this power source is direct current (smoothed full-wave rectification), a constant current is consumed while the level meter integrated circuit IC1 is operating to light any of the light emitting diodes LED1 to LED4, and the light emitting diode is As the number of LEDs 1-4 lit increases, a larger current is required.

[0003]

In this configuration,
As described above, a large amount of current is required to increase the brightness or increase the number of light-emitting displays for the purpose of making the display easier to see and subdividing the display. Therefore, in general, the current consumed by the light emitting display is larger than that of the level meter integrated circuit IC.
There is a problem in that the consumed current becomes excessively large, which causes a problem, and the transformer, the capacitor, and the like have to be relatively large. Therefore, it is difficult to adopt this configuration particularly in a gas alarm device or the like that needs to be downsized.

Therefore, an object of the present invention is to obtain a display device in which the amount of current required for the display device as a whole can be made small, and miniaturization and power saving can be easily achieved. To obtain a gas alarm with characteristics.

[0005]

To achieve this object, a display device according to the present invention has a characteristic configuration in which a plurality of light emitting displays are divided into two groups, and a first light emitting display group and a second light emitting display group. A pair of half-wave rectifying circuits that form a group and half-wave rectify the alternating current from the pair of alternating-current input parts to the full-wave rectifying circuit to separately supply the half-wave rectification to the first light emitting display group and the second light emitting display group. It is equipped with a wave rectifier circuit. Further, a characteristic configuration of the gas alarm device according to the present invention is that the display device of the present invention is provided, and an output signal output corresponding to the gas concentration of the gas to be detected is an input signal input to the drive circuit. is there.
The actions and effects thereof are as follows.

[0006]

That is, in the display device and the gas alarm device of the present application, the half-wave rectification power source obtained from the half-wave rectification circuit is used as the power source of the light emitting display device. Therefore, the light emitting display is turned on every half wave, and the power consumption can be reduced to half that of the conventional one. Here, the device user is looking at an afterimage that remains when the display is turned off. Then, since the substantial lighting time of the light emitting display is shortened, the life of the display is extended, and as a result, power saving and downsizing can be achieved. In addition, since it is equipped with a pair of half-wave rectification circuits and supplies half-wave rectification to each of a plurality of light-emitting displays that are divided into two groups, the change in brightness is reduced and power consumption is reduced compared to the conventional method. Can be halved. In this case, for example, since the half-wave rectification circuit can be constructed by simply inserting the diode, this intermittent drive can be efficiently performed with a small number of parts. On the other hand, in the gas alarm equipped with the display device as described above, power saving and size reduction can be achieved.

[0007]

As a result, the amount of current required for the display device as a whole can be reduced, and miniaturization and power saving can be easily achieved. Furthermore, we were able to obtain a gas alarm with these characteristics.

[0008]

Embodiments of the display device of the present application will be described with reference to the drawings. FIG. 1 shows a circuit of a gas alarm device 2 adopting this display device 1. In FIG. 1, a portion surrounded by a dotted line is a circuit of the display device 1. This display device 1
Is a transformer T for obtaining an alternating current of a predetermined voltage from the alternating current circuit 5, and a bridge diode B for full-wave rectifying the obtained alternating current.
D, a capacitor C for smoothing the same, a level meter integrated circuit IC1 as a driving circuit, and four light emitting diodes LED1 to LED4 as a light emitting display. In this circuit, the level meter integrated circuit IC1 separately controls the light emission drive and drive stop of the four light emitting diodes LED1 to LED4 according to the level of the input signal entering the level meter integrated circuit IC1 and full-wave rectification obtained from the bridge diode BD. Is used as a power source for the level meter integrated circuit IC1.

The above is the display device 1 of the conventional configuration shown in FIG.
This circuit has the same configuration as that of 00, but in this circuit, a pair of diodes D1 and D2 are provided, and half-wave rectification obtained by these diodes D1 and D2 is supplied to the four light emitting diodes LED1 to LED4 described above. Wave rectifier circuit C
1, C2 are provided. That is, four light emitting diodes L
ED1 to ED4 are classified into a first light emitting display group and a second light emitting display group each including two light emitting diodes LED1 and 2 and light emitting diodes LED3 and 4, and a pair of AC inputs connected to a bridge diode BD. Part O and each classified light emitting diode LED1, 2 and LED3, 4
The pair of diodes D1 and D2 described above are connected to the circuit connecting
Are separately arranged. Therefore, the light emitting diode LED1
Pulse currents V2 and V3 are given to each half through diodes D1 and D2 for every 4 to 4, and the current is intermittent due to the half-wave waveform, which is about half that of the conventional circuit. FIG. 2 shows an integrated circuit IC for level meters, LEDs 1 and 2,
The voltages V1, V2, V3 supplied to the LEDs 3 and 4 are shown in time series.

Next, the circuit of the gas alarm device 2 having the display device 1 will be described. This circuit is obtained by adding the detection circuit 3 to the circuit of the display device 1 described above. That is, the detection circuit 3 is provided with the detection sensor S, the comparator IC2, and the buzzer B, and when the sensor output is higher than the set value, the buzzer B operates and issues an alarm. Then, the output from the detection sensor S is sent to the level meter integrated circuit IC1 that constitutes the drive circuit in the display unit 4, and the level is displayed by the light emitting diodes LED1 to LED4.

As described above, the display device 1 of the present application
Is a device which supplies electric power alternately when two or more light-emitting displays (light-emitting diodes) operate, which reduces the change in brightness and halves the electric power as compared with the conventional method. Currently, there are many examples of using integrated circuits ICs for level meters in audio products and the like, but the number of light emitting displays increases to achieve level division, and a large amount of current is required to achieve high brightness. It is said that Therefore, in order to reduce this current, as in the present application, it is possible to adopt half-wave rectification as the power source of the light emitting display and use the afterimage of human eyes for intermittent driving, which leads to power saving and downsizing. It is valid. Here, in the case of the configuration of the present application, this intermittent operation can be efficiently performed with a small number of parts, and the substantial lighting time of the light emitting display is shortened, so that the life of this display is extended.

In the above-mentioned embodiment, the light emitting diode is used as the light emitting display, the bridge diode is used as the full-wave rectifying circuit, the integrated circuit is used as the driving circuit, and the diode is used as the half-wave rectifying circuit. It is also possible to employ a filament lamp as a light emitting display, a rectifying circuit with four diodes as a full-wave rectifying circuit, a driving circuit composed of discrete components as a driving circuit, and a rectifying circuit with two diodes as a half-wave rectifying circuit. . Further, in the above embodiment, the light emitting display provided with four light emitting diodes is shown, but this number can be arbitrarily selected. For example, about 2 to 10 are suitable for proper display. Here, when the number of light emitting indicators is an odd number, the light emitting indicators may be divided into two consecutive natural number groups. Further, in the above embodiment, the selection method of the first light emitting display group and the second light emitting display group is arbitrary, but the first and second light emitting display groups are alternately selected in order from the one having the lowest input signal. In this case, since the light emitting display is turned on almost alternately, it is possible to secure sufficient visibility while reducing the current consumption. It should be noted that reference numerals are added to the claims for convenience of comparison with the drawings, but the present invention is not limited to the configurations of the accompanying drawings by the entry.

[Brief description of drawings]

FIG. 1 is a diagram showing a circuit of a gas alarm device adopting a display device of the present application.

FIG. 2 is a time chart showing a voltage state in each circuit.

FIG. 3 is a diagram showing a circuit configuration of a gas alarm device adopting a conventional display device.

[Explanation of symbols]

 1 display device 5 AC circuit C1 half-wave rectification circuit C2 half-wave rectification circuit BD full-wave rectification circuit LED1 light-emitting display LED2 light-emitting display LED3 light-emitting display LED4 light-emitting display O AC input section

Claims (2)

[Claims] 1. A plurality of light emitting indicators and a drive circuit (IC1) for individually controlling the light emission drive and the drive stop of the plurality of light emitting indicators according to the level of an input signal are provided. A display device using full-wave rectification obtained through a wave rectification circuit (BD) as a power source for the drive circuit (IC1), wherein the plurality of light-emitting displays are divided into two groups, and a first light-emitting display group is provided. And a second light emitting display group, and the first and second light emitting display groups and the second light emitting display are configured by half-wave rectifying alternating current from the pair of alternating current input portions (O) to the full-wave rectifying circuit (BD). A display device provided with a pair of half-wave rectification circuits (C1) and (C2) for individually supplying the half-wave rectification to the device group. 2. A gas alarm device comprising the display device according to claim 1, wherein the output signal output corresponding to the gas concentration of the gas to be detected is input to the drive circuit (IC1). Gas alarm that is a signal.