JPS5831271Y2 - Light source for dimmable smoke detector - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a light source for a dimming type smoke detector, and in particular, the light source can obtain parallel light: a line of luminous flux.

It was devised as such.

Dimming type smoke detectors utilize the fact that when smoke generated during a fire enters the light flux from the light source through the smoke detection space to the receiver, the intensity of the light flux is attenuated. It is a fire detector, and as shown in FIG.
The light is reflected multiple times by the reflecting mirrors 2 and 3 placed across the smoke sensing space, and then enters the light receiving section 4, or the light source section 1 and the light receiving section 4 are connected to a certain smoke sensing space. The light beams are arranged facing each other at a distance, and the optical path length of the light beam is made long, so that a large amount of signal can be obtained due to dimming.

Conventional dimming type smoke detectors use lamps or light emitting diodes as light sources, but since they are not point sources, they do not become parallel light rays due to the lens, for example,
In the case of the light emitting diode 6 shown in the figure, there is primary light emitted from the chip 61 and secondary light emitted from the transparent cover 62 that covers it.
When the lens is focused on the cover 62, a projection phenomenon that appears as a shadow is shown, and when the lens is focused on the cover 62, an enlarged ring-shaped projection phenomenon is shown, and parallel lines cannot be obtained. This method has drawbacks such as the inability to extract a sufficient amount of signal for smoke detection.

This invention is a light source for dimming type smoke detectors that was devised to solve these conventional problems, and as shown in the cross-sectional view of Figure 2, it is an opaque body with openings at both ends. One opening of the case 7 is covered with an insulator 71 equipped with a light emitting diode 6, and one opening of the case 7 is covered with a lens 8.
A translucent plate 9 made of cloudy or cloudy glass, synthetic resin, or the like is arranged near the focal point of the lens 8 in the middle of the case 7 .

The luminous flux 5 from the light source section 1 of this invention configured in this way
Since the light from the light emitting diode 6 is once transferred to the semi-transparent plate 9, the lens 8 has neither the primary light nor the secondary light as explained in the conventional example above, and the semi-transparent plate 9 is the focal point of the lens 8. Since the light enters the inside of the lens, the lines become almost parallel lines, and the projected light can be uniform with almost no unevenness in brightness and darkness, and a relatively high amount of light can be obtained.

Note that if a condenser 91 is provided between the light emitting diode 6 and the semitransparent plate 9 to collect the light from the light emitting diode 6 and reach the semitransparent plate 9, an even higher amount of light can be expected. .

As explained above, when the parallel light beams 5 obtained by the light source section of this invention are adopted as the light source section 1 of a dimming type smoke detector as shown in FIG. Even after multiple reflections, or even when the light source section 1 and the light receiving section 4 are separated for a certain period of time and placed facing each other, a high and even amount of light can be obtained. The amount of light attenuation based on the penetration into the light beam 5 can be increased, and as a result, a large amount of signal for smoke detection can be obtained, which simplifies the electrical processing circuit and makes it easier to set the optical axis during assembly and manufacturing. The light source for dimming type smoke detectors of this invention has excellent effects in the disaster prevention industry.

[Brief explanation of drawings]

FIG. 1 is a schematic explanatory diagram of a dimming type smoke detector, and FIG. 2 is an enlarged sectional view of the light source for the dimming type smoke detector of this invention. 1... Light source part, 4... Light receiving part, 5...
... Luminous flux, 6 ... Light emitting diode, 7 ...
... Opaque case, 8 ... Lens, 9
... Semi-transparent plate, 91 ... Light condenser.

Claims (1)

[Scope of utility model registration request] A light source section of a dimming type smoke and fire detector comprising a light source section and a light receiving section disposed through a smoke sensing space, the light source section being provided at one end of an opaque case with a light source and a lens at the other end, A dimming light source for smoke detection, characterized in that a translucent plate made of cloudy or cloudy glass or synthetic resin is provided inside the opaque case near the focal point of the lens.