JPS586193B2 - Kasaikantiki - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fire detector, and particularly to an oscillating temperature sensing element having a structure in which a temperature sensor, such as vO2, whose resistance value changes rapidly depending on temperature is integrally connected to an oscillating element.

Conventionally, with this type of fire detector, it is usually impossible to determine whether or not the detector is operating normally in the event of an abnormality.Therefore, during testing, an abnormal condition was created and the sensor was examined.

The present invention eliminates the above-mentioned drawbacks, and allows the fire detector to detect a fire by switching the oscillation element during normal oscillation when there is an abnormality, thereby making inspections easier. .

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

Fig. 1 shows the fire detector of the present invention. 1 is a silicon n-type substrate, 2 is a P+ layer doped with P-type impurities on a part of the substrate 1, and 3 is an n-type silicon substrate on P+2. n+1 and 4 doped with impurities at a high concentration are placed on other parts of the n-type substrate 1.
5 is a P+ layer doped with a P type impurity on the other surface of the n1 substrate.

These 1, 2, 3, 4, and 5 constitute an oscillation element A.

Oxide films (Si02) 11 and 12 are attached to both sides of A, and a temperature sensor 6 such as VO2 is attached as a thin film on the Si02 film 11, and an element that integrates element A and the temperature sensor is used as an oscillation temperature sensing element. shall be.

Furthermore, the Si02 film 11 is partially exposed, and an electrode 7 is placed on the n+3 layer, an electrode 8 that is commonly used for the n+4 layer and the sensor 6, an electrode 9 is placed on the P+5 layer, and another electrode 10 is placed on the sensor 6 layer. Add.

13 is an output resistor for taking out the output.

A power supply Vls is applied between the electrodes 8 and T, and a power supply V2 is applied between the electrodes 9 and 10.

Note that the v2 power supply may not be provided, and the temperature sensor 6 may be attached on the Si02 film 12.

Next, the operation of the device of the present invention will be explained. In the configuration shown in FIG. 1, when the temperature is low and the temperature sensor 6 has a high resistance, the potential of the P+5 layer increases due to the injection of holes from the outside, and
When the P+5 layer is higher than the P+5 layer, P+5, n1, P+
2, n+3 cyrisk structure conducts, output resistance 13
A current flows through.

Then, the potential of the P+5 layer decreases to approximately the potential of the n+3 layer.

Since the resistance value of the temperature sensor 6 is so high that it is less than the holding current of Cyrisk, holes are not likely to come out from the P+5 layer, and when electrons from n+3 enter the P+5 layer, the potential of the P+5 layer decreases. Once this occurs, the electrical current in the Cyrisk structure will cease.

However, the nl-P+2 junction remains forward biased until these carriers are exhausted due to the accumulation of excess carriers in the P+2 layer.
Since the transistor structure of ``4, n1, P+2, and n+3 is in a saturated state, a saturation current ``8'' flows when the resistance of the element 13 is R.

When these excess carriers disappear, the current stops completely.

The potential of the P+5 layer remains low, but it gradually rises due to the injection of holes from the outside, and the potential of the P+5 layer remains low.
When the potential of the layer rises above the potential of the 01 layer, the cyrisk structure switches again.

By repeating the above, the oscillation element A oscillates, and the output resistance 1
The oscillation output shown in FIG. 2a can be obtained as the output voltage of 3.

Next, when the temperature rises, the resistance value of the temperature sensor 6 decreases rapidly, and therefore the cyrisk structure P+5, n1, P+2
, n+3 are turned on, the current exceeds the holding current, and the SIRISK continues to conduct.

Then, this silicate current and the saturation current I5 due to the transistor structure continue to flow, and the output resistor 13 is in a state where approximately the voltage of the power supply (1) is applied.

This situation is shown in FIG. 2b.

That is, when the temperature is low, an oscillation output is produced, and when the temperature is high, a large switched current flows.

(Refer to Figure 2 C) As shown in Fig. 2, the present invention integrates the oscillation element and temperature sensor into a thin film, resulting in a very compact and simple configuration.Also, since they are integrated, reliability is improved. Furthermore, the thermal response becomes faster.

During normal operation, an oscillation output is produced, and when the temperature rises, a large current flows through the device, making it easy to check the operation during normal operation.

In other words, since oscillation output is normally output, operation can be checked by observing the oscillation output, and if there is a failure, oscillation is not output, so it is possible to determine whether there is a failure or not, making maintenance extremely easy. has.

[Brief explanation of the drawing]

FIG. 1 shows a fire detector of the present invention, and FIGS. 2a, b, and C are explanatory diagrams for explaining the operation of the device of the present invention. 1... Board, 2... P1, 3...
...n+ layer, 4...n10 layer, 5...P
Ten layers, 6...Temperature sensor, 7, 8, 9, 10...
... Electrode, 11.12 ... Si02 film,
v1, v2... Power supply.

Claims (1)

[Claims] 1. An impurity layer 2 of a conductivity type opposite to that of the substrate is provided on a part of one side of a conductivity type semiconductor substrate 1, and the substrate 1 is further provided on the impurity layer 2.
An impurity layer 3 of the same conductivity type as that of the substrate 1 is provided on another part of one side of the substrate 1, and an impurity layer 5 of the opposite conductivity type to that of the substrate 1 is provided on the opposite side of the substrate 1. An oxide film is attached to the surface of the oscillation element, and a thin film temperature sensor 6 is placed on the oxide film.
A fire detector with a .