Patent ID: 12188865

DETAILED DESCRIPTION OF THE EMBODIMENT

It should be noted that, wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.

One objective of the present disclosure is to provide a smoke detector that increases a variation ratio of light intensity caused by smoke entering the smoke detector by reducing reference light intensity to accordingly improve detection sensitivity and reduce a false alarm rate. The present disclosure further provides a miniaturized optical machine and a manufacturing method thereof.

Please refer toFIGS.2A and2B, they are schematic diagrams of light propagation in a smoke detector200according to some embodiments of the present disclosure.FIG.2Ashows that the smoke detector200includes an optical machine21and a cover23, wherein the cover23has a suitable structure without particular limitations as long as the cover23blocks ambient light to enter the cover23but allows air to go into an inner space thereof.

A light source211of the optical machine21emits light to illuminate an inner surface of the cover23and particles (e.g., smoke) therein. It is assumed that each spot of the inner surface has identical reflection light intensity10S (which is detected by a light sensor213), and particles at different locations have different reflection light intensity, e.g., shown as 0 S, 1 S, 3 S, 7 S and 8 S, but not limited thereto. In this case, a total reflection light intensity of particles is 19 S, and a total reflection light intensity from the inner surface is 50 S (i.e. reference light intensity herein), and thus a ratio therebetween is 0.38.FIG.2Bshows that the smoke detector200is further arranged with a light blocking member22which blocks a part of emission angle of the light source21such that only a part of emission angle generates reflection light. In this case, a total reflection light intensity of particles is 15 S, and a total reflection light intensity from the inner surface is 20 S, and thus a ratio therebetween is 0.75. That is, by arranging the light blocking member22, the ratio between the reflection light intensity of smoke with respect to the reference light intensity is significantly increased, to accordingly improve detection sensitivity of the smoke detector.

Please refer toFIGS.3and4A,FIG.3is a cross sectional view of an optical machine300of a smoke detector according to a first embodiment of the present disclosure; andFIG.4Ais a top view of an optical machine300of a smoke detector according to a first embodiment of the present disclosure. As shown inFIGS.2A and2B, the optical machine300is arranged inside a cover of the smoke detector for detecting reference light intensity at normal time and detecting increment of detected light intensity with existence of smoke.

The optical machine300includes a substrate310, a first light source311, a light sensor313and a light blocking member32. In one aspect, the optical structure300further includes a side wall315arranged on the substrate310and surrounding the light sensor313and the first light source311. The light blocking member32is preferably attached to a top surface of the side wall315such that the first light source311and the light sensor313are located inside inner spaces formed by the substrate310, the side wall315and the light blocking member32. Preferably, the inner space in which the light source311is located and the inner space in which the light sensor313is located are separated by the side wall315such that light emitted by the light source311is not directly (i.e. without reflection) received by the light sensor313.

The substrate31is a printed circuit board or a flexible board without particular limitations as long as the substrate31is electrically coupled with the first light source311and the light sensor313, and transmits electric signals and power required thereby.

The light sensor313is a CMOS image sensor or a single photon avalanche diode (SPAD). The light sensor313is arranged on the substrate310, such as via wire bonding, but not limited to. In other aspects, the light sensor313is electrically coupled and fixed on the substrate310using other known ways.

The first light source311is a light emitting diode or a laser diode, and has a first emission angle EA, e.g., referring toFIG.5. The first light source311is arranged on the substrate310such as via wire bonding, but not limited to. In other aspects, the first light source311is electrically coupled and fixed on the substrate310using other known ways.FIG.4Ashows that the first light source311and the light sensor313are arranged on the substrate310in a first direction (shown as left-right direction).

It should be mentioned that the first light source311and the light sensor313are not limited to be arranged parallel to upper and lower edges of the substrate310.

The light blocking member32is made of opaque materials such as plastic, rubber, wood, metal or a combination thereof without particular limitations. The light blocking member32has a first opening321upon the first light source311, and blocks a part of (shown as right part) of a first emission angle EA of the first light source311far away from the light sensor313, i.e. the first opening321exposing a part of (shown as left part) the first emission angle EA of the first light source311close to the light sensor313. In this way, a part of emission light of the first light source311is blocked as shown inFIG.2Bto reduce detected reference light intensity of the light sensor313.

The light blocking member32further has a second opening322upon the light sensor313. In one aspect, the second opening322exposes the whole light sensor313. In another aspect, the light blocking member32blocks a part of (shown as left part) of the light sensor313far away from the first light source311, i.e. the second opening322exposing a part of (shown as right part) the light sensor313close to the first light source311, so as to further reduce the detected reference light intensity of the light sensor313.

Please refer toFIG.5again, it shows that when the light blocking member32blocks different areas of the first light source311, reflection light intensity of the smoke90is changed. In one aspect, an opening edge32E of the first opening321far away from the light sensor313is aligned with a first edge E1of the first light source311far away from the light sensor313. It is seen fromFIG.5that a part of the first emission angle EA of the first light source311is blocked by the light blocking member32. In another aspect, the opening edge32E of the first opening321far away from the light sensor313is aligned with a central line of the first light source311, and an effective emission angle changes to EA1. In an alternative aspect, the opening edge32E of the first opening321far away from the light sensor313is aligned with a second edge E2of the first light source311close to the light sensor313, and an effective emission angle changes to EA2.

In an alternative aspect, the opening edge32E of the first opening321far away from the light sensor313is arranged between a first edge E1of the first light source311and a central line of the first light source311. The opening edge32E is closer to the first edge E1and farther from the central line, e.g., the light blocking member32blocking less than 25% of the first light source311. The purpose of arranging the first opening321in this way is to keep enough reference light intensity when there is no smoke in the cover, e.g., the cover23shown inFIGS.2A and2B. If the reference light intensity is too weak, scattered light intensity (i.e. reflected by smoke90) can fluctuate significantly in different operating conditions.

In the present disclosure, an area of the first light source311to be blocked by the light blocking member32is previously determined by parameters including, for example, light emission intensity, arranged environment of the smoke detector, reflectivity of an inner surface of the smoke detector and required sensitivity.

Please refer toFIG.4B, it is another top view of an optical machine300′ of a smoke detector according to a first embodiment of the present disclosure. In this aspect, the optical machine300′ further includes a second light source315having a second emission angle (also referring toFIG.5).FIG.4Bshows that the first light source311, the light sensor322and the second light source315are arranged on the substrate310along the first direction, and the light sensor322is between the first light source311and the second light source315. Preferably, the first light source311and the second light source315emit light of different wavelengths. For example, emission light of the first light source311has a wavelength of 460 nm, and emission light of the second light source315has a wavelength of 880 nm, but not limited thereto. One objective of arranging light sources of different wavelengths at two opposite sides of the light sensor is referred to U.S. patent application Ser. No. 17/320,222, entitled “smoke detector” filed on May 14, 2021, and assigned to the same assignee of the present application, and the full disclosure of which is incorporated herein by reference.

In this aspect, the light blocking member32further has a third opening323upon the second light source315, and light blocking member32blocks a part of (shown as left part) a second emission angle of the second light source315far away from the light sensor313, i.e. the third opening323exposing a part of (shown as right part) the second emission angle of the second light source315close to the light sensor313. In this aspect, the second opening322preferably exposes the whole light sensor322. In other aspects, the optical machine300′ is further arranged with a third light source317, which emits a light wavelength, e.g., 525 nm, different from the first light source311and the second light source315, but the present disclosure is not limited to.

It should be mentioned that althoughFIG.4Bshows that the third light source317and the first light source311are at the same side of the light source313, the present disclosure is not limited thereto. In other aspects, the third light source317is located at the same side of the light sensor313with the second light source315, i.e. left side.

It should be mentioned that althoughFIG.4Bshows that the third light source317and the first light source311shares the first opening321, the present disclosure is not limited thereto. In other aspects, the light blocking member32further has an individual opening corresponding to the third light source317and separated from the first opening321, i.e. each light source corresponding to a respective opening. In the present disclosure, the light blocking member32covers a part of an emission angle, referring toFIG.5, of every light source.

The smoke detect300has a larger size when a light blocking member32is used to be attached to the side wall315. The present disclosure further provides an optical machine that can reduce a total size of the smoke detector.

Please refer toFIG.6E, it is a cross sectional view of an optical machine600of a smoke detector according to a second embodiment of the present disclosure. The optical machine600also includes a substrate610, a light source611and a light sensor613, which are respectively identical to the above substrate310, light source311and light sensor313, and thus details thereof are not repeated herein. The difference between the second embodiment and the first embodiment is that the optical machine600does not use a light blocking member to cover upon the optical machine600so as to reduce the size.

The optical machine600has a transparent gel64for encapsulating the light sensor613, the light source611and a part of surface of the substrate610, and has a first tilted surface64S1extending from a first side of the transparent gel64close to the light source611to above the light source611. An angle (with respect to a surface of the substrate610) of the first tilted surface64S1is between 15 degrees and 80 degrees, but not limited thereto. The transparent gel64is made of any suitable transparent material (especially transparent to emission light of the light source611) without particular limitations, and maintains solid state under room temperature.

The optical machine600further has a first light blocking layer643formed on the first side and the first tilted surface64S1of the transparent gel64so as to block a part of an emission angle of the light source300far away from the light sensor613. In this embodiment, the first light blocking layer643is a metal layer formed on the surface of the transparent gel64by, for example, sputtering, evaporation or coating. The metal is light reflective material or light absorption material. The light reflective material is selected from Al, Ag and Au, but not limited to. The light absorption material is selected from Cr, but not limited to. The thickness of the metal layer is, for example, between 0.5 μm and 10 μm.

Depending on how much the light source611is desired to be blocked (referring toFIG.5), an angle and a length of the first tilted surface64S1is determined. Furthermore, depending on how much the light source611is desired to be blocked, it is able to determine whether to extend the first light blocking layer643to an upper surface of the transparent gel64. For example, if it is desired to form the effective emission angle EA2, the first light blocking layer64is extended from the first tilted surface64S1to cover a part of an upper surface of the transparent gel64above the light source611.

To prevent emission light of the light source611from directly propagating to the light sensor613, the optical machine600further includes a light blocking wall641in the transparent gel64, and between the light source611and the light sensor613. The light blocking wall641is formed by filling opaque material inside a vertical trench of the transparent gel64, wherein the material of the light blocking wall641is not particularly limited as long as the emission light of the light source611is blocked. In one aspect, a width at an upper part of the light blocking wall641is larger than that at a lower part of the light blocking wall641to improve the light blocking effect.

To further reduce detected reference light intensity of the light sensor613, the optical machine600further includes a second light blocking layer645formed on a second side of the transparent gel64close to the light sensor613and on a part of the upper surface of the transparent gel64upon the light sensor613. For example, the transparent gel64further has a second tilted surface64S2extending from the second side to above the light sensor613, and the second light blocking sensor645is formed on the second tilted surface64S2. An angle (with respect to the surface of substrate610) of the second tilted surface64S2is between 15 degrees and 80 degrees, which is identical to or different from that of the first tilted surface64S1without particular limitations.

It should be mentioned that although the above embodiments are illustrated in the way that the light blocking layer is formed on the first side and the second side of the transparent gel64, the present disclosure is not limited thereto. In other aspects, the light blocking layer is formed at all side surfaces of the transparent gel64.

Please refer toFIGS.6A to6D, they are cross sectional views of manufacturing an optical machine600of a smoke detector according to a second embodiment of the present disclosure. Firstly, a substrate610is provided, and a light source611and a light sensor613are arranged on the substrate610, as shown inFIG.6A. It is possible to manufacture multiple (e.g., shown as two herein, but not limited to) optical machines600at the same time. Next, a transparent gel64is formed on the substrate610to encapsulate the light source611, the light sensor613and a part of upper surface of the substrate610, as shown inFIG.6B. Next, cutting means in semiconductor packaging process (e.g., cutting blade) is used to cut a vertical trench641P, a first tilted surface64S1and a second tilted surface64S2, as shown inFIG.6C. Next, the cutting blade is used to separate different optical machines600, as shown inFIG.6D. Finally, opaque material is filled in the vertical trench641P to form the light blocking wall641, and a metal coating layer (used as light blocking layer) is formed at the side (all or a part of side surface), the first tilted surface64S1and the second tilted surface64S2of the transparent gel64to accomplish the optical machine600according to the second embodiment of the present disclosure. The part of the surface of the transparent gel64unwilling to form the light blocking layer is firstly formed with a mask, which is then removed after the light blocking layer is accomplished. That is, the light blocking layer is formed by photolithography process.

Please refer toFIG.7, in other aspects, the light blocking wall643is not formed by filling opaque material in the vertical trench641P of the transparent gel64but formed by coating a metal layer on the surface of the vertical trench as the light blocking layer741, e.g., formed using the same way as the first light blocking layer643and the second light blocking layer645.

In another aspect, the first light blocking layer643extends into the transparent gel64to block a part of an emission angle of the light source613far away from the light sensor613, e.g., using cutting means mentioned above. In other words, the metal coating layer for light blocking is formed on and/or inside the transparent gel64without particular limitations as long as the detected reference light intensity of the light sensor613is decreased.

In another aspect, the optical machine uses an external light source, i.e. not including a light source therein. For example referring toFIG.6E, in this aspect the optical machine includes a right half part of the right optical machine inFIG.6E. That is, the optical machine includes the substrate610, the light sensor613, the transparent gel64and the light blocking layer645. The optical sensor613is arranged on the substrate610. The transparent gel64encapsulates the light sensor613and a part of surface of the substrate610, and has a tilted surface64S2extending from the side of the transparent gel64to above the light sensor613. The light blocking layer645is formed on the side (all or a part) of the transparent gel64and the tilted surface64S2so as to block a part of an upper area of the light sensor613. In this aspect, the light blocking layer645extends only to the tilted surface64S2or further to an upper surface of the transparent gel64depending on the required reference light intensity.

The above first and second embodiments can be combined to form another embodiment of the present disclosure.

As mentioned above, the conventional smoke detector has a larger size and a high false alarm rate due to the environmental change. Accordingly, the present disclosure further provides a smoke detector (e.g.,FIGS.3to5) that improves a ratio of light intensity variation with respect to reference light intensity by reducing the reference light intensity inside a cover. In addition, the present disclosure further provides a miniaturized optical machine (e.g.,FIGS.6E and7) and a manufacturing method thereof (e.g.,FIGS.6A to6E) that use a coating layer to replace a light blocking member of the smoke detector to reduce the size thereof.

Please refer toFIG.8, it is an operational schematic diagram of an optical machine300′ of a smoke detector according to a third embodiment of the present disclosure. To further improve total intensity of scattered light from the smoke90, a tilted top surface is arranged at a light blocking wall35between the first light source311and the light sensor313. Accordingly, a range of the smoke90being illuminated by the first light source311is increased. The light blocking wall35is used to block light emitted by the first light source311to directly propagate to the light sensor313.

In this embodiment, a height H of the light blocking wall35is preferably arranged between a half of an arranged height of the light blocking member32and the same height as the arranged height of the light blocking member32. Meanwhile, an inclined angle of the top surface is determined, for example, according to the height H of the light blocking wall35as well as a transverse distance between the light blocking wall35and the first light source311.

Furthermore, it is possible to combine the third embodiment to the first embodiment and/or the second embodiment to form an alternative embodiment.

Although the disclosure has been explained in relation to its preferred embodiment, it is not used to limit the disclosure. It is to be understood that many other possible modifications and variations can be made by those skilled in the art without departing from the spirit and scope of the disclosure as hereinafter claimed.