摘要:
Each lens of a multi-segment lens is a Fresnel lens in which a second surface, being the reverse side surface of a first surface, has a plurality of lens surfaces. At least one of the plurality of lens surfaces is configured from a part of a side surface of an elliptical cone having a central axis oblique to a normal line of the first surface. Any normal line intersecting with the lens surface configured from the part of the side surface of the elliptical cone among normal lines of respective points on the first surface is non-parallel to a central axis of the elliptical cone corresponding to the lens surface with which the any normal line intersects.
摘要:
A fire alarm system, determining existence or nonexistence of a fire by using an ultrasound wave, comprises a sound wave generator and a sound wave detector to detect sound waves propagated through two propagation paths having different lengths each other. The system comprises a calculation means for calculating a pressure ratio between a first sound pressure, which is a sound pressure of a sound wave propagated through a first propagation path, and a second sound pressure, which is a sound pressure of a sound wave propagated through a second propagation path, and a smoke density estimator. The smoke density estimator calculates a change ratio between the pressure ratio calculated by the calculation means and a predetermined standard pressure ratio, and determines a smoke density from the change ratio based on a predetermined relational expression describing the relation between the change ratio and the smoke density, and determines existence of a fire when the smoke density exceeds a predetermined threshold.
摘要:
An infrared flame detector of the present invention has an infrared radiation receiving element accommodated in a package. In the infrared radiation receiving element, a set of two pyroelectric elements are arranged side by side and connected in anti-series on a pyroelectric element forming substrate. An infrared optical filter includes a filter forming substrate made of an infrared radiation transmitting material, a set of two narrowband transmission filter sections formed at positions respectively corresponding to positions of the pyroelectric elements on a first surface of the filter forming substrate and configured to transmit infrared radiation of a first selective wavelength and infrared radiation of a second selective wavelength, and a broadband blocking filter section formed on a second surface of the filter forming substrate and configured to absorb infrared radiation of a wavelength longer than an upper limit of an infrared reflection band.
摘要:
A semiconductor substrate is anodized to be shaped into an optical lens. Prior to being anodized, the substrate is finished with an anode pattern on its bottom surface so as to be consolidated into a unitary structure in which the anode pattern is precisely reproduced on the substrate. The anodization utilizes an electrolytic solution which etches out oxidized portion as soon as it is formed as a result of the anodization, to thereby develop a porous layer in a pattern in match with the anode pattern. The anode pattern brings about an in-plane distribution of varying electric field intensity by which the porous layer develops into a shape complementary to a desired lens profile. Upon completion of the anodization, the semiconductor substrate is shaped into the lens by etching out the porous layer and the anode pattern from the substrate.
摘要:
An infrared detector includes a circuit block carrying an infrared sensor element and electronic components. The circuit block is composed of a dielectric resin layer and a first substrate formed with a circuit pattern and mounting the electronic components. The dielectric resin layer is formed in its top with a recess which defines around its periphery with a shoulder for supporting opposite ends of the infrared sensor. The first substrate is integrated to the lower end of the dielectric resin layer with at least one of the electronic components being molded into the dielectric resin layer to make the circuit block of a unified mold structure. Thus, a part or all of the electronic components are molded into the dielectric layer to realize the circuit block of a simple and low profile structure, while retaining an advantage of keeping the infrared sensor element sufficiently away from the electronic components and an associated electronic circuit, thereby assuring to give the infrared detector which is simple in construction, economical in cost, and reliable in the infrared detection.
摘要:
The present invention provides a smoke sensor of sound wave type that excels in responsiveness and has a low probability of false detection. The smoke sensor has a sound wave generating unit that provides an ultrasound wave to a monitoring space, a sound wave receiving unit that receives the ultrasound wave from the sound wave generating unit via the monitoring space, and a signal processing unit that detects an abnormality of the monitoring space by using an output of the sound wave receiving unit. The signal processing unit includes a smoke density estimation unit that estimates a smoke density in the monitoring space on the basis of a difference between the output of the sound wave receiving unit and a standard value, and a smoke density determination unit that determines the abnormality of the monitoring space by comparing the smoke density estimated by the smoke density estimation unit with a predetermined threshold.
摘要:
A semiconductor substrate with anode pattern is anodized to be shaped into an optical lens. The anodization utilizes an electrolytic solution which etches out oxidized portion as soon as it is formed as a result of the anodization, to thereby develop a porous layer in a pattern in match with the anode pattern. After being removed of the porous layer, the substrate is treated to smooth out minute projections remaining in the top surface of the substrate, thereby obtaining the lens of good transmissivity.
摘要:
An infrared detector includes a circuit block carrying an infrared sensor element and electronic components. The circuit block is composed of a dielectric resin layer and a first substrate formed with a circuit pattern and mounting the electronic components. The dielectric resin layer is formed in its top with a recess which defines around its periphery with a shoulder for supporting opposite ends of the infrared sensor. The first substrate is integrated to the lower end of the dielectric resin layer with at least one of the electronic components being molded into the dielectric resin layer to make the circuit block of a unified mold structure. Thus, a part or all of the electronic components are molded into the dielectric layer to realize the circuit block of a simple and low profile structure, while retaining an advantage of keeping the infrared sensor element sufficiently away from the electronic components and an associated electronic circuit, thereby assuring to give the infrared detector which is simple in construction, economical in cost, and reliable in the infrared detection.
摘要:
An improved fire alarm system capable of reliably detecting the presence of fire caused by different sources. The fire alarm system detects a smoke density (S) as well as a temperature difference (&Dgr;T) within a predetermined time interval, and has primary criteria of (i) whether the smoke density (S) exceeds a smoke threshold [e.g., S>5%/m]; (ii) whether the temperature difference (&Dgr;T) exceeds a temperature difference threshold [e.g., &Dgr;T≧18 C]; and (iii) whether a combination of S and &Dgr;T satisfies an inequality [e.g. 2S+&Dgr;T≧12] which is based upon a decreasing function of &Dgr;T with an increase of S. The detected smoke density and the temperature difference are examined with reference to the primary criteria so as to provide a fire warning signal indicating a possible fire presence when anyone of the above primary criteria is satisfied.