JPH097079A - Fire sensor for housing - Google Patents

Abstract

PURPOSE: To confirm a power supply display with moderate visibility in a neither too light nor tool dark state without being affected by ambient illumination. CONSTITUTION: The fire sensor for housing which is equipped with a power supply display part 16 which shows that the sensor is supplied with electric power and in operation, and generates an alarm by deciding fire occurrence when the detected quantity of a predetermined physical quantity exceeds a predetermined threshold is provided with an ambient illumination detection part DP which detects the lightness in the ambient environment where the sensor is installed and a light intensity adjustment part DP which increases the light intensity of the power supply display part as the detected illumination of the ambient illumination detection part increases. Further, the power supply display part 16 is constituted including a serial connection between a display element DL and a photodetecting element DP which makes a current flow easier accompanying increase of the quantity of received light.

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a residential fire detector provided with an energizing display indicating that it is energized and is operating.

[0002]

2. Description of the Related Art A fire detector for a house is installed on a ceiling or a wall in a dwelling unit, detects a predetermined physical quantity such as smoke density or heat, and when the detected quantity exceeds a predetermined threshold value. It is supposed to notify you that a fire has occurred.

By the way, FIG. 3 is a circuit block diagram showing a conventional residential fire detector. As shown in FIG. 3, the conventional residential fire detector 1 includes a power supply circuit 10, a constant voltage circuit 11, a smoke detection circuit 12, an electronic buzzer circuit 13, a timer circuit 14, and a control circuit 15. An energization lamp circuit 16 corresponding to an energization display unit is provided.

The power supply circuit 10 is a commercial power supply (AC100
V) is used to generate a required DC voltage, which is supplied to each internal circuit as a driving power supply. The constant voltage circuit 11 is for supplying power to a circuit that requires stable voltage supply with little fluctuation in voltage, and stabilizes and outputs the DC voltage generated and output by the power supply circuit 10 with high accuracy.

The smoke detection circuit 12 has, for example, a light-emitting portion (not shown) and a light-receiving axis in a darkroom space surrounded by a so-called labyrinth that has a breathability but blocks outside light from entering. The light receiving axis of the part (not shown) is arranged substantially orthogonally,
When smoke particles that have entered the dark space diffusely reflect the light from the light emitting unit so that the light is incident on the light receiving unit, and the light receiving unit receives the diffused light above a predetermined threshold value,
Outputs a fire occurrence signal.

When the electronic buzzer 13 is energized, the electronic buzzer sounds an alarm sound to notify the occurrence of a fire. When the switch S is turned on, the timer circuit 14 outputs the forced ringing signal only for 5 seconds. When receiving the fire occurrence signal from the smoke detection circuit 12 or the forced ringing signal from the timer circuit 14, the control circuit 15 energizes the electronic buzzer 13 to ring the electronic buzzer 13.

The energizing lamp circuit 16 is composed of a current limiting resistor R and a light emitting diode D _L corresponding to a display element connected in series. The current-carrying lamp circuit 16 sends a current to the light emitting diode D _L to cause it to emit light, and the current home fire detector is supplied with power. If a fire occurs, it is in an operation state in which an alarm can be sounded. I am informed.

The energizing lamp circuit 16 is connected between the output of the constant voltage circuit 11 and the ground. That is, a constant voltage is always applied to the series circuit of the current limiting resistor R and the light emitting diode D _L. That is, the current flowing through the light emitting diode D _L is always constant. Also,
Intensity of light emitting from the LED D _L (brightness) is proportional to the current flowing through the light emitting diode D _L. Therefore, the light intensity (brightness) emitted from the light emitting diode D _L is always constant.

[0009]

However, in many cases, the above-mentioned residential fire detector is mainly installed on the ceiling of a bedroom or the like. Therefore, when the energized display unit is bright and bright, there are people who are worried that they cannot sleep, and when the energized display unit is low and dark, they lose their brightness in a bright room and the energized display unit There is a problem that it is difficult to confirm the display state (lighting state).

The present invention has been made in order to solve the above problems, and an object of the present invention is not to be influenced by ambient illuminance and to be always bright and not too dark. It is to provide an excellent residential fire detector that can confirm

[0011]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides a power-on display section for indicating that the power is on and is operating. A residential fire detector that reports that a fire has occurred when the detected physical quantity exceeds a predetermined threshold.The ambient illuminance detector detects the brightness of the surrounding environment and the detection of the ambient illuminance detector. A luminosity adjusting unit for increasing the luminosity of the energization display unit as the illuminance increases is provided.

According to the second aspect of the present invention, the device is provided with an energization display section that indicates that the device is energized and is in operation, and when a detected amount of a predetermined physical quantity exceeds a predetermined threshold value, it is reported that a fire has occurred. In the residential fire detector described above, the current-carrying display unit is configured to include a series connection of a display element and a light-receiving element that facilitates the flow of current as the amount of received light increases.

According to the third aspect of the present invention, the device is provided with an energization display section that indicates that the device is energized and is in operation, and when a detected amount of a predetermined physical quantity exceeds a predetermined threshold value, it is reported that a fire has occurred. In the residential fire detector, the current-carrying display unit is configured to include a series connection of a current limiting resistor and a display element, and a light receiving element for facilitating a current to flow in parallel to the current limiting resistor as the amount of received light increases. It is characterized by being connected.

According to a fourth aspect of the invention, the light receiving element is a photodiode.

According to a fifth aspect of the present invention, the light receiving element is a photoconductive element.

[0016]

With the above construction, in the invention according to claim 1, the luminous intensity adjusting section of the energization display section is provided if the detected illuminance increases in accordance with the illuminance detected by the ambient illuminance detecting section. If the luminous intensity is increased and the detected illuminance is reduced, the luminous intensity of the energization display unit can be reduced.

According to the second aspect of the invention, even if the voltage applied to the current-carrying display section is constant, the light-receiving element tends to flow a current as the amount of light received increases, so that the ambient illuminance increases. For example, the current flowing through the display element increases and the luminous intensity emitted by the display element increases.

According to the third aspect of the invention, even if the voltage applied to the current-carrying display section is constant, the light-receiving element connected in parallel with the current limiting resistor can easily flow a current as the amount of light received increases. Therefore, when the ambient illuminance increases, the current flowing through the display element increases, and the luminous intensity emitted by the display element increases. In addition, even if the surroundings become completely dark and the light receiving element is in a state in which almost no current flows, the minimum luminous intensity of the energization display section can be secured by the current flowing through the current limiting resistor.

According to the invention described in claim 4, in the photodiode, the current easily flows as the ambient illuminance increases, and the linearity with respect to the incident light is good and the wavelength sensitivity can be made close to the visible sensitivity. . Therefore, it is possible to perform rational light intensity adjustment that matches the display element with human visual recognition characteristics.

According to the invention of claim 5, the photoconductive element is such that an electric current easily flows as the ambient illuminance increases, and the linearity with respect to incident light is good and the wavelength sensitivity is close to the visible sensitivity. You can Therefore, it is possible to perform rational light intensity adjustment that matches the display element with human visual recognition characteristics.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of a fire detector for a house according to the present invention will be described in detail below with reference to FIGS. FIG.
Is a circuit block diagram showing a residential fire detector, and FIG. 2 is a perspective view showing a state where the residential fire detector is looked up from below. In FIGS. 1 and 2, the same parts as those of the residential fire detector described in the related art are designated by the same reference numerals, and detailed description of the same parts will be omitted.

The fire detector 1 for a house is installed on a ceiling surface and, as shown in FIG. 2, is provided with a box-shaped synthetic resin outer shell case 1a having a slightly rounded corner. At the center of the lower surface of the outer shell case 1a, a slightly flat and substantially cylindrical smoke detecting section 1b
Is provided. Further, in the vicinity of the peripheral edge of the lower surface of the outer shell case 1a, a sound passage hole 1c for passing a ringing sound, a lighting window 1d for taking in ambient illuminance into the internal space surrounded by the outer shell case 1a, and an energization display A display window 1e that transmits the light emitted from the unit and a drawstring 1f for ringing test are provided.

The fire detector 1 for a house is provided with various circuit parts as shown in FIG. 1 inside. That is, the power supply circuit 10
A constant voltage circuit 11, a smoke detection circuit 12, an electronic buzzer circuit 13, a timer circuit 14, a control circuit 15, and an energization lamp circuit 16 corresponding to an energization display unit.

As is clear from a comparison between FIG. 1 and FIG. 3, the residential fire detector 1 shown in FIG. 1 is different from the conventional one in that it has the following features. That is, the current limiting resistor R is connected in parallel with the photodiode D _P that facilitates the flow of current as the amount of received light increases.

The photodiode D _P is mounted on the semiconductor chip with p
When an n-junction portion is provided and light is applied to the pn-junction portion, an electron and a hole are paired, and the impedance of the pn-junction portion changes. In addition, the photodiode D
_P has good linearity with respect to incident light, and wavelength sensitivity can be made close to visible sensitivity by using sealing glass having an appropriate light transmission spectrum.

Therefore, in the residential fire detector 1 shown in FIG. 1, the photodiode D _P has a high impedance when the surroundings are dark and there is no light incident on the photodiode D _P from the lighting window 1d. Light emitting diode D
Most of the current flowing through _L is only I _R flowing through the current limiting resistor R. However, when the surrounding becomes bright and the amount of light incident on the photodiode D _P from the lighting window 1d increases, the impedance of the photodiode D _P becomes low and the current flowing through the light emitting diode D _L becomes a current limiting resistor R.
Is the sum of I _R flowing through the diode and I _DP flowing through the photodiode D _P.

That is, in the residential fire detector 1 shown in FIG. 1, the current I _DL flowing through the light emitting diode D _L is I _DL.
= (I _R + I _DP ). Moreover, the light emitting diode D _L
Since a current flows in the forward direction, the voltage applied to the light emitting diode D _L is constant at about 0.2 V, so that I _R flowing through the current limiting resistor R is constant regardless of whether the surroundings are bright or dark. And I flowing through the photodiode D _P
Only _DP increases as the surrounding area becomes brighter and decreases as it becomes darker.

That is, the light emitting diode D _L emits weak light (light of low intensity) corresponding to I _R flowing through the current limiting resistor R when the surroundings are pitch dark, and current limiting resistor R when the surroundings are bright. It is possible to emit strong light (light of high intensity) corresponding to the total current of I _R flowing through the diode and I _DP flowing through the photodiode D _P.

That is, in the fire detector 1 for a house shown in FIG. 1, when the surroundings are dark, the light is weak, and the brighter the surroundings are, the stronger the lighting is. "The power is being supplied,
If a fire occurs, it is in an operating state in which an alarm can be sounded. ”It is possible to confirm the energization display through the display window 1e.

Further, as is clear from the above description,
In other words, the photodiode D _P increases the luminous intensity of the ambient illuminance detection unit that detects the brightness of the surrounding environment and the light intensity of the light emitting diode D _L that corresponds to the display element of the energization display unit as the detected illuminance of the ambient illuminance detection unit increases. It can be said that it also has a light intensity adjusting unit.

The present invention is not limited to the above embodiment, but the photodiode is replaced by cadmium sulfide (CdS).
Or cadmium selenide (CdSe) or a solid solution of both can bring the wavelength sensitivity close to the visible sensitivity.
It goes without saying that it may be replaced with a photoconductive element whose specific resistance decreases as the amount of light received increases.

[0032]

Since the residential fire detector of the present invention is constructed as described above, the invention of claim 1 is not too bright and not too dark without being influenced by the ambient illuminance. It has an effect that it is possible to provide an excellent residential fire detector that can always check the energization operation state with proper visibility and can sleep well even when installed in the bedroom.

According to the second aspect of the present invention, since the light receiving element that makes it easier to pass an electric current as the amount of received light increases, an excellent residential fire that achieves the above effect with a simple structure and at a low cost The effect that a sensor can be provided is produced.

According to the invention of claim 3, in addition to the above effect, even if the surroundings are dark and the light receiving element is in a state in which almost no current flows, the current flowing through the current limiting resistor causes the current-carrying display. This has the effect of providing an excellent residential fire detector that can secure the minimum luminous intensity of the part.

According to the invention of claim 4 or claim 5, in addition to the above-mentioned effects, since the linearity with respect to the incident light is good and the wavelength sensitivity is close to the visible sensitivity, human visual recognition characteristics are obtained. It is possible to provide a further excellent fire detector for a home, which can perform a rational adjustment of the luminous intensity of the energization display that matches the above.

[Brief description of drawings]

FIG. 1 is a circuit block diagram showing an embodiment of a residential fire detector according to the present invention.

FIG. 2 is a perspective view showing a state in which the residential fire detector of the above embodiment is looked up from below.

FIG. 3 is a circuit block diagram showing a conventional residential fire detector.

[Explanation of symbols]

1 Residential fire detector 16 Energization display section R Current limiting resistance _DL Display element D _P Ambient illuminance detection section (light intensity adjustment section, light receiving element, photodiode, photoconductive element)

Claims (5)

[Claims] 1. A fire detector for a house, which is equipped with a power-on display section for indicating that power is being supplied and is in operation, and which issues a fire when a detected amount of a predetermined physical quantity exceeds a predetermined threshold value. A residential fire characterized by including an ambient illuminance detection unit that detects the brightness of the surrounding environment and a luminosity adjustment unit that increases the luminosity of the energization display unit as the illuminance detected by the ambient illuminance detection unit increases. sensor. 2. A residential fire detector, comprising a power-on display section for indicating that power is being supplied and is in operation, and which issues a fire alarm when a detected amount of a predetermined physical quantity exceeds a predetermined threshold value. A fire detector for a house, characterized in that the display part is configured to include a series connection of a display element and a light-receiving element for facilitating the flow of current as the amount of received light increases. 3. A fire detector for a house, comprising a power-on display section for indicating that power is being supplied and is in operation, and which reports that a fire has occurred when a detected amount of a predetermined physical quantity exceeds a predetermined threshold value. The display unit is configured to include a current-limiting resistor and a display element in series connection, and the current-limiting resistor is connected in parallel with a light-receiving element that facilitates the flow of current as the amount of light received increases. Fire detector. 4. The fire detector for a house according to claim 2, wherein the light receiving element is a photodiode. 5. The fire detector for a house according to claim 2, wherein the light receiving element is a photoconductive element.