CN117037412A - Smoke detector - Google Patents

Abstract

A smoke detector includes a substrate, a light source, and a light sensor. The light source and the light sensor are adjacently arranged on the substrate. An asymmetric structure is configured on the substrate to shift the illumination area of the light source toward the position of the light sensor to increase the ratio of the smoke reflected light to the reference light intensity.

Description

Smoke detector

Technical Field

The present invention relates to a smoke detector, and more particularly to a smoke detector that reduces false alarm rates and is adaptable to different specifications.

Background

In current photoelectric smoke detectors, the light sensor does not receive any reflected light from the light source when no smoke is present, and only when smoke enters the smoke detector does the light sensor receive reflected or scattered light from the light source. Meanwhile, the inner side surface of the smoke detector is plated with a light absorption material so as to prevent the light sensor from generating internal reflection when no smoke enters. However, when the amount of dust accumulated in the smoke detector is sufficiently large, light is reflected inside the smoke detector and received by the photosensor, resulting in a false alarm.

The action mechanism of the scattering type smoke detector is to start an alarm when the scattered light intensity generated by the smoke to the light source is larger than a single alarm threshold value.

However, because of the different types of flame that produce smoke and light interactions, such as smoldering ash smoke, that produce several times more scattered light than burning black smoke, setting a single alarm threshold will make the smoke detector too sensitive to certain types of smoke to easily produce false alarms (false alarm) while being insensitive to other smoke to delay alarm timing.

In addition, the environment typically has many sources of interference, such as moisture, water vapor, oil smoke, cigarettes, dust, insects, etc., that can alter the reflected light signal intensity to cause false alarms. These factors make the false alarm rate of smoke detectors currently on the market still high and can only reduce false alarms in a negative way, e.g. avoiding installation of smoke detectors in places with too many sources of interference (e.g. kitchen, bathroom, garage etc.) to reduce the probability of false alarms, but there is no complete and effective solution.

Disclosure of Invention

In view of this, the present invention provides a smoke detector that can effectively reduce the incidence of false alarms and can accommodate different specifications.

The present invention provides a smoke detector including a light sensor that is capable of detecting reference light energy when no smoke enters a detection space of the smoke detector as a reference for determining the occurrence of a fire.

The invention also provides a smoke detector which can avoid the light sensor from detecting the reflected light of accumulated dust, so as to reduce false alarm rate.

The invention also provides a smoke detector capable of automatically adjusting a plurality of condition thresholds according to the detection result of the light sensor so as to reduce false alarm rate.

The invention also provides a smoke detector in which the illumination range of the light source is offset towards the light sensor to increase the intensity of scattered light.

The invention provides a smoke detector comprising a substrate, a light source, a light sensor and an annular wall. The light source and the light sensor are disposed on the upper surface of the substrate. The annular wall is arranged on the upper surface of the substrate and surrounds the light source, and is used for enabling the illumination range of the light source to be offset towards the light sensor.

The invention also provides a smoke detector comprising a substrate, a light source, a light sensor and a light guide element. The light source and the light sensor are disposed on the upper surface of the substrate. The light guide element is used for shifting the illumination range of the light source towards the light sensor.

The invention also provides a smoke detector comprising a substrate, a light sensor, a secondary substrate and a light source. The light sensor is disposed on the upper surface of the substrate. The secondary substrate is configured on the upper surface of the substrate and is electrically connected with the substrate, and the first surface of the secondary substrate is inclined towards the light sensor. The light source is configured on the first surface of the secondary substrate.

To make the above and other objects, features and advantages of the present invention more apparent, the following detailed description will be made in conjunction with the accompanying drawings. In the description of the present invention, the same members are denoted by the same reference numerals, and the description thereof will be given earlier.

Drawings

Fig. 1A is a perspective view of a housing of a smoke detector according to a first embodiment of the invention;

fig. 1B is a cross-sectional view of a smoke detector according to a first embodiment of the invention;

FIG. 1C is another cross-sectional view of a smoke detector according to a first embodiment of the invention;

fig. 2 is a perspective view of a housing of a smoke detector according to a second embodiment of the invention;

FIG. 3 is a cross-sectional view of a smoke detector according to a second embodiment of the invention, wherein the housing is taken along line A-A' in FIG. 2;

fig. 4 is a side view of a variation of the smoke detector of the second embodiment of the invention;

fig. 5A is a schematic diagram of a detection element of a smoke detector of a third embodiment of the invention;

fig. 5B is a cross-sectional view of a smoke detector according to a third embodiment of the invention;

FIG. 6 is a schematic diagram of a smoke detector with multiple sets of preset condition thresholds versus different profiles of detection signals and different smoke types according to an embodiment of the present invention;

FIGS. 7A-7C are schematic diagrams of detection signals of different smoke species detected by a smoke detector according to embodiments of the present invention;

FIGS. 8A-8C are schematic diagrams of detection signals of different detection objects detected by a smoke detector according to embodiments of the present invention;

FIG. 9 is a schematic diagram of the operation of a smoke detector according to an embodiment of the invention, showing the smoke detector having a variable detection frequency;

FIGS. 10A and 10B are schematic diagrams illustrating light transmission within a smoke detector according to embodiments of the present invention;

FIG. 11 is a graph showing the relationship between the intensity of scattered light detected by a smoke detector according to an embodiment of the present invention and various light source shielding ratios and light source assembly shifts;

fig. 12 and 13 are cross-sectional views of a smoke detector according to a fourth embodiment of the invention;

fig. 14A to 14C are cross-sectional views of a smoke detector according to a fifth embodiment of the present invention; and

Fig. 15A and 15B are cross-sectional views of a smoke detector according to a sixth embodiment of the present invention.

Description of the reference numerals

1200. 1300, 1400, 1500 smoke detector

1001. Detection element

1010. Substrate board

1011. Light source

1013. Light sensor

1003. Cover body

1201. 1301, 1401 and 1501 first side wall

1203. 1303, 1403, 1503 second side walls

1405. 1405', 1505 lenses

1407. 1407' reflector

1507. Secondary substrate

Detailed Description

The smoke detector of the embodiment of the invention is provided with a processor, and the built-in classifier can identify different smoke types and dust types and change the condition threshold value for giving out an alarm according to the detection result so as to reduce the occurrence rate of false alarms. In addition, the smoke detector of the embodiment of the invention is provided with the protruding structure to shield scattered light and reflected light of accumulated dust and/or is provided with a plurality of light sources to identify the types of the interferents. The interfering substances include, for example, smoke, dust, water vapor, accumulated dust, and the like.

Referring to fig. 1A to 1C, fig. 1A is a perspective view of a housing 12 of a smoke detector 100 according to a first embodiment of the present invention; fig. 1B is a cross-sectional view of a smoke detector 100 according to a first embodiment of the invention; fig. 1C is another cross-sectional view of the smoke detector 100 of the first embodiment of the invention, showing smoke entering the detection space of the smoke detector 100 to increase the amount of reflection.

The smoke detector 100 includes a detection element 11 and a cover 12, and the cover 12 covers the detection element 11 such that the detection element 11 is located in an internal space (as a detection space) of the cover 12. For example, the detection element 11 is provided on the base 10 having an area larger than or equal to the cover 12, and one surface of the base 10 is combined with the cover 12 and the other surface is fixed to a wall surface or ceiling where the smoke detector 100 is required to be provided. The material of the base 10 is not particularly limited, and may be plastic, glass, wood, or the like.

The cover 12 includes a reflective surface 120 and a side wall 121, where the side wall 121 extends from an edge of the reflective surface 120 or a region near the edge, for example, fig. 1B and 1C show that the side wall 121 extends from the reflective surface 120 perpendicularly toward the arrangement direction of the detection element 11, but the invention is not limited to the side wall 121 being perpendicular to the reflective surface 120, for example, may have an inclination angle. The side wall 121 has apertures in order to allow air (and smoke if present) to enter the interior space of the smoke detector 100. For example, fig. 1A shows an embodiment in which the sidewall 121 includes a plurality of spaced apart pillars (pilar) extending from the edge of the light reflecting surface 120, with the spacing between the pillars being the aperture. In order to prevent external light from entering the internal space of the smoke detector 100 to affect the detection capability, the side wall 121 is preferably configured such that the internal space is not directly visible from the outside of the housing 12, but the shape of the column is not limited to that shown in fig. 1A. The reflective surface 120 is used for reflecting the light emitted by the light source 111.

In another embodiment, the sidewall 121 extends from the base 10 (e.g., below in fig. 1B and 1C), and the cover 12 is a flat plate without a sidewall. The cover 12 closes the detection space of the smoke detector 100 by being coupled to the top of the side wall 121 of the base 10.

In another embodiment, the base 10 and the cover 12 each have a sidewall 121 and correspond to each other. The housing 12 closes the detection space of the smoke detector 100 by combining the base 10 and the top of the side wall 121 of the housing 12. The cover 12 may be bonded to the base 10 by an adhesive or a locking member, and is not particularly limited.

The detecting element 11 includes a light source 111, a light sensor 113, and a processor 13 electrically connected to the light source 111 and the light sensor 113. A light blocking wall is preferably provided between the light source 111 and the light sensor 113.

The smoke detector of embodiments of the invention is configured such that the light sensor is still able to receive a reference light intensity to generate a reference detection signal Sdr when no smoke enters its interior space. The light source 111 preferably uses a non-coherent light source, such as a light emitting diode. The light source 111 is configured to emit a main beam (main beam) ELm toward the reflective surface 120 to generate a main reflected beam (main reflected beam) RLm reflected from the reflective surface 120, wherein the main beam ELm refers to light within an emission angle of the light source 111. In other embodiments, if the light source 111 is provided with an optical element for diffusing the emission angle of the light source 111, a laser diode may be used for the light source 111.

The photosensor 113 is, for example, a CMOS image sensor, a photodiode (photo diode), or a single photon breakdown diode (SPAD), which detects reflected light (including at least a portion of the main reflected light beam RLm) reflected from the light reflecting surface 120 at a predetermined frequency to generate a detection signal. For example, the photosensor 113 is disposed on the optical path of the main reflected light beam RLm or a region close to the optical path, but is not limited thereto.

The processor 13 is for example a Microprocessor (MCU) or an Application Specific Integrated Circuit (ASIC). The processor 13 receives a reference detection signal Sdr (shown in fig. 1B) generated by the photosensor 113 when no smoke enters or intercepts the main reflected light beam RLm and receives a current detection signal Sdc (shown in fig. 1C) generated by the photosensor 113 when smoke enters or intercepts the main reflected light beam RLm. In one embodiment, the magnitude of the reference detection signal Sdr is determined according to the spatial relationship among the light source 111, the light sensor 113, the side wall 121 and the reflecting surface 120, and the reflection coefficient of the reflecting surface 120.

The processor 13 determines whether to issue an alarm according to the signal ratio of the current detection signal Sdc to the reference detection signal Sdr, for example, sdc/Sdr or (Sdc-Sdr)/Sdr. As shown in fig. 1C, when smoke 80 enters the interior space (intervening the path of the main reflected light beam RLm), the light sensor 113 will simultaneously detect reflected light RLm1 (reflected by the reflecting surface 120) and RLm2 (reflected by the smoke 80), so that Sdc > Sdr, where Sdc is mainly generated by the sum of RLm1 and RLm2 of fig. 1C, and Sdr is mainly generated by RLm of fig. 1B. For example, when the signal ratio (or normalized intensity) of the Sdc/Sdr or (Sdc-Sdr)/Sdr exceeds a predetermined value, such as TH2 shown in fig. 9, the processor 13 controls the speaker or a host (not shown) to which the speaker is coupled to emit an alarm. For example, the smoke detector 100 itself or the host computer has a speaker. The normalized intensity of FIG. 9 is calculated as Sdc/Sdr.

In more detail, in the first embodiment, when the light source 111 and the light sensor 113 are disposed at the same height in the inner space, the light source 111 and the light sensor 113 are symmetrically disposed at two sides of the reflecting position, such as the left and right sides of fig. 1B, with respect to the reflecting position of the reflecting surface 120. It can be appreciated that when the reflective surface 120 is not parallel to the plane of the same height, the light source 111 and the light sensor 113 are asymmetrically disposed at two sides of the reflective position. For example, the photosensor 11 is disposed in a region where reflected light is strongest.

In another embodiment, the photosensor 113 is disposed near (but not near) the area receiving the strongest reflected light to avoid too high reference detection signal Sdr to reduce the sensitivity of the photosensor 113. As described above, the current detection signal Sdc is greater than the reference detection signal Sdr, and the intensity of the reference detection signal Sdr is preferably not the maximum detectable value of the light sensor 113.

Referring to fig. 2 to 4, fig. 2 is a perspective view of a housing 32 of a smoke detector 300 according to a second embodiment of the present invention; fig. 3 is a cross-sectional view of a smoke detector 300 according to a second embodiment of the invention, wherein the housing 32 is a cross-section along line A-A' in fig. 2; fig. 4 is a schematic diagram of a modification of the smoke detector 300 according to the second embodiment of the present invention.

The smoke detector 300 also includes a detection element 31 and a cover 32, and the cover 32 covers the detection element 31 so that the detection element 31 is located in the internal space (as a detection space) of the smoke detector 300. Similarly, the detection element 31 is provided on a base 30 having an area greater than or equal to that of the housing 32, and the base 30 may be combined with the housing 32 and fixed to a wall or ceiling on which the smoke detector 300 is to be provided. Similarly, the material of the base 30 is not particularly limited.

In the second embodiment, the configuration of the detecting element 31 is the same as the detecting element 11 of the first embodiment, and only different numbers are used for designation. The light sensor 313 is configured to receive reflected light RL1 of the emission light beam EL of the light source 311 to generate a detection signal Sd. The second embodiment differs from the first embodiment in the structure of the cover 32.

The cover 32 includes a bottom 320 and a sidewall 321, and the sidewall 321, like the sidewall 121 of the first embodiment, extends from the edge of the bottom 320 and has a hole. For example, the sidewall 121 includes a plurality of spaced apart pillars extending from the edge of the bottom surface 320. Similar to the first embodiment, according to different embodiments, the side wall 321 is disposed on the base 30, or disposed on both the bottom surface 320 and the base 30.

In the second embodiment, the bottom surface 320 further has a plurality of protrusions 323 extending from the bottom surface 320, and the plurality of protrusions 323 are used to block the reflected light RL2 reflected by the bottom surface 320 (or the dust 90 if there is accumulation). As shown in fig. 3, the light sensor 313 mainly receives reflected light RL1 from the upper surfaces of the plurality of protrusions 323 to generate a detection signal Sd. Therefore, even if the bottom surface 320 accumulates the dust 90, most of the reflected light RL2 reflected by the dust 90 is blocked by the plurality of protrusions 323 from being received by the light sensor 313. Therefore, whether dust 90 is accumulated on the bottom surface 320 does not affect the reference value of the detection signal Sd (i.e., the reference detection signal).

As described above, the present invention determines whether to issue an alarm according to the signal ratio of the current value of the detection signal Sd (i.e., the current detection signal) to the reference value of the detection signal Sdr (similar to fig. 1B when no smoke enters the detection space), such as Sd/Sdr or (Sd-Sdr)/Sdr. According to the configuration of the second embodiment, since the reference value of the detection signal Sdr is not affected by the accumulated dust 90, the false alarm rate can be effectively reduced.

It should be noted that, although fig. 2 shows the plurality of protrusions 323 as being elongated parallel to each other, this is only for illustrating, not limiting the present invention. In other embodiments, the plurality of protrusions 323 may be cylinders, triangular cylinders, rectangular cylinders, or a combination thereof, which are separated from each other and are staggered, without particular limitation, as long as the reflected light RL2 can be shielded. The height of the plurality of protrusions 323 may be determined according to the lateral distance between the light source 311 and the light sensor 313 and the longitudinal height of the detection space, and is not particularly limited as long as the plurality of protrusions 323 can shield the reflected light RL2.

In addition, although fig. 3 shows the plurality of elongated protrusions 323 extending over the entire bottom surface 320, the present invention is not limited thereto. In other embodiments, the plurality of protrusions 323 may be disposed only in the illumination range of the main light path of the light source 311. In another embodiment, elongated protrusions 323 parallel to each other are provided in the illumination range of the main light path of the light source 311, and elongated protrusions 323 having different extending directions are provided in other areas of the bottom surface 320.

Referring to fig. 3 again, in one embodiment, the light source 311 and the light sensor 313 are disposed opposite to the bottom surface 320, and the plurality of protrusions 323 are used for shielding the reflected light RL2 of the light beam EL emitted by the light source 311 reflected by the bottom surface 320. As described above, when the dust 90 is accumulated on the bottom surface 320, the reflected light RL2 is reflected by the dust 90. When the plurality of protrusions 323 are elongated, the elongated extending direction is perpendicular to the direction of the lateral component (e.g., the left-right direction in fig. 3) of the emitted light beam EL of the light source 311, so as to effectively block the reflected light RL2.

Referring to fig. 4, a side view of a variation of a smoke detector 400 according to a second embodiment of the invention is shown. In another embodiment, the cover 32 further includes a reflective surface 422 disposed on the inner surface of the sidewall 421, and the light source 411 and the light sensor 413 are also disposed on the inner surface of the sidewall 421 and located opposite to the reflective surface 422. Similar to the first embodiment, the side wall 421 extends upwardly from the housing or downwardly from the base depending on the application. In the present embodiment, the reflective surface 422 is not located on the bottom surface 420 of the cover, and the material of the reflective surface 422 is not particularly limited as long as the reflective surface can reflect the light beam EL emitted from the light source 411.

More specifically, in the present embodiment, the light source 411 does not project the emission light beam EL toward the plurality of projections 423. Since the light sensor 413 receives more or less reflected light from the bottom surface 420 (in the case where the protrusion 423 is not provided) in operation, the reference value of the detection signal is increased when the bottom surface 420 accumulates the dust 90. Therefore, the present embodiment also reduces the influence of the accumulated dust 90 on the reference value of the detection signal Sd by providing the plurality of projections 423 on the bottom surface 420 to reduce the false alarm rate. The plurality of protrusions 423 are identical to the plurality of protrusions 323 of fig. 3, and thus are not described herein.

More specifically, the difference between fig. 4 and fig. 3 is the arrangement of the light source and the light sensor, and the arrangement of fig. 4 is such that the emitted light beam EL and the reflected light RL1 are transmitted over the plurality of protrusions 423. It will be appreciated that the smoke detector 400 of fig. 4 also includes a processor electrically connected to the light sensor 413 to process the detection signal from the light sensor 413.

Referring to fig. 5A and 5B, fig. 5A is a schematic diagram of a detecting element 51 of a smoke detector 500 according to a third embodiment of the invention; fig. 5B is a cross-sectional view of a smoke detector 500 according to a third embodiment of the invention. The smoke detector 500 also includes a detecting element 51 and a cover 52, wherein the cover 52 can be combined with the base 50 to form a detecting space, and the description thereof is omitted herein.

It should be noted that, although fig. 5B shows the cover 52 being identical to the cover 12 of the first embodiment, in other embodiments, the cover 52 may be identical to the cover 32 of the second embodiment, and is not particularly limited. In more detail, the third embodiment is different from the first and second embodiments described above mainly in the element configuration of the detection element 51.

The detection element 51 includes a light sensor 513, a processor 53, and a first light source 511 (or 512) and a second light source 511 '(or 512'). Similar to the first embodiment, the light sensor 513 may be a CMOS image sensor, a photodiode, or a SPAD, without particular limitation. The light sensor 513 is used to detect scattered light and reflected light from the housing 52, smoke 80 or suspended dust 90' when the different light sources are on to generate a detection signal, such as a light intensity signal.

The first light source 511 and the second light source 511' emit light of the same wavelength, such as 525 nm or 850 nm, but not limited to this wavelength. The first light source 511 and the second light source 511 'may be coherent light sources or different coherent light sources, and are respectively disposed on two opposite sides of the light sensor 513 and preferably have the same distance from the light sensor 513, for example, fig. 5A shows that the first light source 511 is disposed on the left side of the light sensor 513 and the second light source 511' is disposed on the right side of the light sensor 513. Preferably, a light blocking wall is provided between the light sensor 513 and the light sources 511, 511'.

The processor 53 is, for example, a microprocessor or an asic, and is configured to receive, from the light sensor 513, a first detection signal Sd1 generated by the light sensor 513 when the first light source 511 emits light and a second detection signal Sd2 generated by the light sensor 513 when the second light source 511' emits light. In one embodiment, the first light source 511 and the second light source 511 'emit light in different periods, so that the first light source 511 does not contribute to the intensity of the second detection signal Sd2 and the second light source 511' does not contribute to the intensity of the first detection signal Sd 1.

The processor 53 separates the smoke 80 from the suspended dust 90' according to the similarity of the first detection signal Sd1 and the second detection signal Sd2. For example, when the difference or standard deviation of the first detection signal Sd1 and the second detection signal Sd2 is smaller than the predetermined threshold, the first detection signal Sd1 and the second detection signal Sd2 are similar to each other; otherwise, the first detection signal Sd1 and the second detection signal Sd2 are not similar to each other.

For example, referring to fig. 5B, when the first light source 511 and the second light source 511' are sequentially turned on, the processor 53 sequentially receives the first detection signal Sd1 and the second detection signal Sd2. When smoke 80 enters the interior space (i.e., detection space) of smoke detector 500, smoke 80 is generally uniformly distributed within housing 52, so that the intensities of first reflected light RL1 and second reflected light RL2 are substantially the same, resulting in normalized intensities (Sd 1-Sdr 1)/Sdr 1 and (Sd 2-Sdr 2)/Sdr 2 (or Sd1/Sdr1 and Sd2/Sdr 2) being also substantially the same, where Sdr1 is a first detection signal (or referred to as a first reference detection signal) when no smoke or dust enters the detection space and Sdr2 is a second detection signal (or referred to as a second reference detection signal) when no smoke or dust enters the detection space. The intensity normalization of the detection signal is used to eliminate the effect of the light emission decay of the light sources 511 and 511'.

However, when the dust 90 'enters the housing 52, the dust 90' is not necessarily uniformly distributed in the housing 52 due to the small wind direction and the small amount, so the intensities of the first reflected light RL1 and the second reflected light RL2 are different, and the first detection signal Sd1 and the second detection signal Sd2 are also different. Thus, the processor 53 can distinguish between the interference caused by the suspended dust 90' by configuring the light sources of the same wavelength on different sides of the light sensor 513 to reduce the false alarm rate. Thereby, the processor 53 recognizes the intensity variation of the smoke 80 and the suspended dust 90'.

It should be noted that although fig. 5A shows 511 and 511 'being symmetrical to the photosensor 513 (the same phase d), and 512' being symmetrical to the photosensor 513 (the same phase d), the present invention is not limited thereto. In other embodiments, 511 'is disposed at 512' or 511 is disposed at 512, i.e., not parallel to the lateral direction of fig. 5A.

In addition, in the third embodiment, light sources with different wavelengths may be disposed on the same side of the light sensor 513, for example, the third light source 512 and the first light source 511 are disposed on the same side of the light sensor 513, the third light source 512' and the second light source 511' are disposed on the same side of the light sensor 513, or the two third light sources 512 and 512' are disposed on opposite sides of the light sensor 513, respectively. The wavelength of light emitted from the third light source 512 (or 512 ') is different from the wavelengths of light emitted from the first and second light sources 511 and 511'. In the present embodiment, the processor 53 also receives the third detection signal Sd3 when the third light source 512 and/or 512 'emits light (not simultaneously emits light with the first light source 511 and the second light source 511') from the light sensor 513. The processor 53 judges the smoke or dust type based on the characteristic value relationship between the normalized intensities (Sd 1-Sd 1)/Sd 1 (or normalized intensity (Sd 2-Sd 2)/Sd 2) and normalized intensity (Sd 3-Sd 3)/Sd 3, where Sd3 is a third detection signal (or referred to as a third reference detection signal) when no smoke or dust enters the detection space.

For example, referring to fig. 7A to 7C, although the light wavelengths of the first light source 511 and the third light source 512 are different, when the smoke 80 enters the internal space of the smoke detector 500, the light intensity variation (or trend) of the first detection signal Sd1 and the third detection signal Sd3 is similar. Therefore, the processor 53 can identify whether the interfering object is the smoke 80 according to the characteristic values of the detection signals Sd1 and Sd3, wherein the characteristic values include the normalized intensity values of the first detection signal Sd1 and the third detection signal Sd3, the moving average (moving average) over time, the slope, the standard deviation, the peak interval, the type of the filter used, and the like, but are not limited thereto.

Therefore, when the light intensity changes of the first detection signal Sd1 and the third detection signal Sd3 are different (or the characteristic values are different), the processor 53 determines that the interfering object is the suspended dust 90' because of the low similarity; when the light intensity changes of the first detection signal Sd1 and the third detection signal Sd3 are substantially the same (or the feature value is the same), the processor 53 determines that the smoke 80 enters the internal space because of the high similarity. Thus, the smoke detector 500 can eliminate the interference caused by the dust 90' to reduce the false alarm rate.

In the above-mentioned determination mode, if the third light source 512 'is disposed beside the second light source 511', the processor 53 compares the characteristic values of the second detection signal Sd2 and the third detection signal Sd3 to distinguish the smoke from the suspended dust.

In addition, the processor (including 13, 33 and 53) of the smoke detector (including 100, 300, 400 and 500) according to the embodiments of the present invention is further configured to select a set of condition thresholds from a plurality of sets of preset condition thresholds according to a profile (profile) or the above characteristic value of a current detection signal generated by the light sensor (including 113, 313, 413 and 513) to compare with the current detection signal to determine whether to issue an alarm.

For example, referring to fig. 6, it shows profiles (profile 1 to profile 4) of different detection signals and different smoke types (type 1 to type 4), respectively preset with a set of condition thresholds; that is, A1 to A4 (different from each other), B1 to B4 (different from each other), and C1 to C4 (different from each other) represent thresholds of different feature values, respectively. In the present invention, the smoke detector sounds an alarm when each set of condition thresholds are met simultaneously.

In one embodiment, when the smoke detector of the present invention includes only a single wavelength light source, the processor sets or selects a set of condition thresholds currently used according to the current detection signal, such as Sd3 of fig. 7A-7C. For example, when the processor determines that the slope of the current normalized intensity (Sd 3-Sdr 3)/Sdr 3 or Sd3/Sdr3 is greater than B1, a set of preset condition thresholds are selected with respect to profile 1 in FIG. 6; thus, when the current normalized intensity (Sd 3-Sdr 3)/Sdr 3 or the intensity of Sd3/Sdr3 is greater than A1, the smoke detector sounds an alarm. However, before an alarm is given in the detection process, when the processor further determines that the slope of the current normalized intensity (Sd 3-Sdr 3)/Sdr 3 or Sd3/Sdr3 is greater than B2 (e.g., B2> B1), a set of preset condition thresholds with respect to profile 2 in fig. 6 are selected; thus, when the current normalized intensity (Sd 3-Sdr 3)/Sdr 3 or the intensity of Sd3/Sdr3 is greater than A2, the smoke detector sounds an alarm. In other words, in operation of the smoke detector according to the embodiment of the present invention, when the processor determines that the profile of the detection signal changes over time, then the processor actively selects another set of condition thresholds from a plurality of sets (e.g., 4 sets are shown in fig. 6, but not limited to) of preset condition thresholds. Thus, the condition threshold can be dynamically changed according to the actual condition so as to reduce the false alarm rate.

It should be noted that, although fig. 6 shows a plurality of sets of preset condition thresholds, the present invention is not limited thereto. In other embodiments, the smoke detector may have built-in (in memory) sets of preset condition threshold ranges (i.e., containing upper and lower thresholds).

In one embodiment, when the smoke detector according to the embodiment of the present invention includes light sources with two wavelengths (i.e., different dominant wavelengths), each set of preset condition thresholds may further include a signal ratio (or feature ratio) of detection signals with different wavelengths. For example, when the processor determines that the slope of the current normalized intensity (Sd 3-Sd 3)/Sd 3 or Sd3/Sd 3 is greater than B1, an alarm is issued when the current normalized intensity (Sd 3-Sd 3)/Sd 3 or Sd3/Sd 3 is greater than A1 while the signal ratio (or feature ratio) of the detected signals (e.g., sd3 and Sd 1) or the normalized intensity of the two wavelengths is less than C1.

It should be noted that the number of condition thresholds of the set of preset condition thresholds is not particularly limited.

In the present invention, the plurality of sets of preset condition thresholds are stored in the memory of the processor in advance, for example, the user can change the plurality of sets of preset condition thresholds according to the requirement, for example, different sets of preset condition thresholds are selected according to different national specifications (including UL268 and UL217 in the united states, EN1464 and EN54 in europe, etc., but not limited to) and different setting environments (for example, indoor or outdoor). More particularly, the smoke detector of the present invention has a plurality of sets of preset condition thresholds that can be selected or changed to correspond to different operating environments.

In addition, as shown in fig. 7A to 7C, because the smoke generated by the paper fire, the wood fire and the foam fire (foam fire) is different, the detection signals are also different, so that the relation among the characteristic values is also different. For example, the processor of the present invention has a classifier built into it, which is composed of hardware and/or firmware. When the processor receives at least one detection signal (e.g., at least one of Sd1, sd2, sd 3), the type of smoke is classified first according to the characteristic value of one detection signal or the characteristic value relationship of two detection signals. Next, the processor selects a set of preset condition thresholds corresponding to smoke categories (category 1 through category 4 as shown in fig. 6). In fig. 7A to 7C, the vertical axis is the normalized intensity value of the detection signal. For example, the processor calculates the average value of the signal during a predetermined period (e.g., 10 seconds) at the initial time of operation as a reference value, and then divides the value of the current detection signal at the time of operation by the reference value minus 1 (as a normalized intensity value), so as to obtain the detection signals of Sd1 to Sd3 of fig. 7A to 7C.

In fig. 6, period 1 to period 4 are, for example, time intervals, which indicate that all preset condition thresholds in the predetermined time interval need to be met to generate an alarm.

It should be noted that although fig. 6 shows that the smoke type and the profile of the detection signal have the corresponding preset condition threshold sets, the present invention is not limited thereto. In other embodiments, the smoke type and the profile of the detection signal may correspond to completely different sets of preset condition thresholds. That is, the fog type and the profile of the detection signal determine different sets of condition threshold sets.

In addition to identifying different smoke types, the smoke detector of the embodiments of the present invention can also distinguish whether it is a smoke change detection signal generated by a flame. For example, as shown in fig. 8A to 8C, the profiles (or intensity variations) of the detection signals caused by smoke, dust, and water vapor are different. When the processor in the embodiment of the invention recognizes that the signal change occurs in the detection signal (for example, the signal change is greater than TH1 as shown in fig. 9), the built-in classifier determines whether the contour of the signal change is caused by flame. For example, when the classifier recognizes that the profile of the detection signal is caused by dust, water vapor or other non-flame, the processor does not compare the feature of the detection signal with any one of the predetermined set of condition thresholds to avoid false alarm. When the classifier recognizes that the profile of the detection signal belongs to the flame, the processor further selects a set of preset condition thresholds suitable for the current situation (determined by the characteristic value of the current detection signal), and compares the set of preset condition thresholds with the subsequent detection values to determine whether to send out an alarm.

In addition, the smoke detector (including 100, 300, 400 and 500) according to the embodiment of the invention can change the detection frequency according to the current detection signal, so as to shorten the reaction time. For example, referring to fig. 9, in the initial (no significant change in the detection signal), the light sensor of the smoke detector generates the detection signal at the first detection frequency. When the processor judges that the normalized intensity value of the detection signal is greater than or equal to the first threshold value TH1, the processor indicates that a fire disaster is likely to happen, and the processor controls the light sensor to increase to a second detection frequency (simultaneously increases the flicker rate of the light source). And when the processor judges that the normalized intensity value of the detection signal is greater than or equal to the second threshold value TH2, an alarm is sent out.

It should be noted that, although fig. 9 illustrates the condition of issuing an alarm by the normalized intensity value exceeding the second threshold TH2, the present invention is not limited thereto. In other embodiments, the alarm may be set up after a set of preset condition thresholds as shown in fig. 6 are all met.

Similarly, the first threshold TH1 may be replaced by a set of preset condition thresholds instead of a single condition. Meanwhile, the first threshold TH1 and the second threshold TH2 can be dynamically and actively changed according to the specification, the current detection signal, the smoke type, and the like, instead of being self-adjusted or fixed by the user.

It should be noted that the detection signals mentioned in the descriptions related to fig. 7A-7C, fig. 8A-8C and fig. 9 may be the detection signals mentioned in the above-mentioned first to third embodiments. In other words, the processor in each of the first to third embodiments may select a set of preset condition thresholds, identify interfering objects, and/or adjust the sampling frequency according to the current detection signal.

In the description of the present invention, dust (part) refers to, for example, a substance floating in air, and dust (durt) refers to a substance accumulated at the bottom of the cover for convenience of description.

In the present description, the normalized intensity value may be calculated from (current detection value/reference detection value) as shown in fig. 9, or from (current detection value/reference detection value) -1 as shown in fig. 8A-8C and fig. 9A-9C.

In the description of the present invention, in order to distinguish smoke, dust and dust, when judging the smoke type and deciding whether to send out warning, the processor normalizes the current detection signal with the reference detection signal so as to eliminate the influence of light source attenuation.

As described above, the optical smoke detector may be set to determine whether or not to issue an alarm, for example, (pdc-Sdr)/Sdr, which may be referred to as scattered light intensity, based on the signal ratio of the current detection signal pdc to the reference detection signal Sdr. However, the reference detection signal Sdr may be changed with the change of the ambient temperature and the offset of the component assembly position, so as to generate a false alarm. By increasing the signal ratio of the current detection signal Sdc to the reference detection signal Sdr, the occurrence rate of false alarms can be reduced.

Referring to fig. 10A and 10B, schematic diagrams of light transmission in a smoke detector 1000 according to some embodiments of the invention are shown. Fig. 10A shows a smoke detector 1000 comprising an opto-mechanical structure 1001 and a housing 1003.

The light source 1011 of the opto-mechanical structure 1001 emits light to illuminate the interior space of the enclosure 1003 and suspended particles (e.g., smoke, represented by dots not on the interior surface) within the enclosure 1003, and assumes that the reflected light intensity at each location of the interior surface is 10S (detected by the light sensor 1013) and that the suspended particles at different locations have different reflected light intensities, shown as, for example, 0S, 1S, 3S, 7S, and 8S, but is not limited thereto. At this time, the ratio of the total reflected light intensity 19S (or referred to as scattered light intensity) of the suspended particles to the total reflected light intensity (i.e., reference light intensity for generating a detection signal) 50S of the inner surface is 0.38. Fig. 10B shows smoke detector 1000 further provided with a light barrier 1002 that masks part of the light emission angle of light source 1011 so that only a partial area inside housing 1003 can generate reflected light. At this time, the ratio of the total reflected light intensity 15S of the suspended particles to the total reflected light intensity 20S of the inner surface was 0.75. That is, by disposing the light blocking member 1002, the ratio of the smoke reflected light to the reference light intensity can be greatly increased, thereby increasing the detection sensitivity of the smoke detector 1000.

However, the proportion of the light-blocking member 1002 that blocks the light source 1011 is not unlimited. Since the reference light intensity and the scattered light intensity are used together to determine whether to send out an alarm, if the reference light intensity is too low, the scattered light intensity will also vary significantly with different conditions.

For example, referring to fig. 11, it shows the floating of scattered light intensity caused by different offset positions of the light source 1011 (e.g., b=0 for no offset, b=negative for offset near the light sensor 1013, and b=positive for offset far from the light sensor 1013) at different shading ratios a of the light source 1011 (e.g., a=0 for no shading; a=1 for complete shading). The vertical axis of fig. 11 represents the light intensity. As can be seen from fig. 11, when the shading ratio of the light source 1011 is between 10% and 40% (i.e., a=0.1 to 0.4), the scattered light intensity is less affected by the different positional shifts of the light source 1011. In fig. 11, the preferred shielding ratio is 25%, i.e., the light blocking member 1002 shields the right 1/4 of the light source 1001 in fig. 10B.

The light blocking member 1002 is configured to reduce the reference light intensity. However, it is noted that the same object can be achieved by increasing the intensity of scattered light. The same effect of similarly configuring the flag 1002, i.e., the improvement (Sdc-Sdr)/Sdr, is also achieved with the optical smoke detector of other embodiments of the present invention presented below. In the drawings of the following embodiments, a processor, which performs the above-described functions, is omitted.

Referring to fig. 12 and 13, there is shown a cross-sectional view of smoke detectors 1200 and 1300 according to a fourth embodiment of the present invention. The smoke detectors 1200 and 1300 include an opto-mechanical structure 1001 and a housing 1003, wherein the housing 1003 is described above, and thus, description thereof is omitted.

The optical-mechanical structure 1001 includes a substrate 1010, a light source 1011, and a light sensor 1013, wherein the light source 1011 and the light sensor 1013 are disposed on the upper surface of the substrate 1010. The substrate 1010 may be a Printed Circuit Board (PCB) or a flexible substrate, without particular limitation. The light source 1011 and the light sensor 1013 are the same as the light source 111 and the light sensor 113 in the above embodiment, and thus are not described here again.

The optomechanical structure 1001 further includes a ring wall disposed on the upper surface of the substrate 1010 and surrounding the light source 1011 and the light sensor 113. The annular wall is made of opaque material and is used for limiting the illumination range of the light source 1011 and the light receiving range of the light sensor 113. The annular wall prevents light from the light source 1011 from being transmitted directly to the light sensor 113. In this embodiment, the annular wall is further configured to shift the illumination range of the light source 1011 toward the light sensor 1013, for example, the right wall of the housing 1003 is not illuminated by the light source 1011 in the figure to decrease the intensity of the reference light (e.g., shown as R) and increase the intensity of the reflected light (i.e., scattered light intensity, shown as S) of the smoke 90.

In this embodiment, the inner wall surface of the annular wall is a reflective surface, for example, formed by coating a metal surface on the inner wall surface or polishing the inner wall surface, but the invention is not limited thereto, and the reflective surface may be formed in other manners.

In fig. 12, the annular wall around the light source 1011 is perpendicular to the upper surface of the substrate 1010. A first portion 1201 of the annular wall around the light source 1011 (right side of the light source 1011 in fig. 12) remote from the light sensor 1013 is higher than a second portion 1203 of the annular wall (left side of the light source 1011 in fig. 12) close to the light sensor 1013, so that the reference light R toward the right side wall of the housing 1003 is reflected by the first portion 1201 to increase the intensity of the smoke reflected light S illuminating the smoke 90. In one embodiment, the height of the first portion 1201 is more than twice the height of the second portion 1203. The thickness of the first portion 1201 in the left-right direction in fig. 12 is not particularly limited. The height of the annular wall connecting the first portion 1201 and the second portion 1203 may be configured to be equal to the second portion 1203 or to be sequentially increased from the second portion 1203 toward the first portion 1201, without particular limitation.

In fig. 13, the annular wall around the light source 1011 also includes a first portion 1301 (right side of the light source 1011 in fig. 12) away from the light sensor 1013 and a second portion 1303 (left side of the light source 1011 in fig. 12) close to the light sensor 1013. To achieve a similar effect as in fig. 12, the first portion 1301 is inclined towards the light sensor 1013, the inclination angle of which is shown as a2. Fig. 13 shows that the second portion 1303 also slopes towards the light sensor 1013, the slope angle of which is shown as a1. In fig. 13, the inclination angle a2 may be equal to or different from a1, and is not particularly limited, for example, a1 and a2 are greater than 0 degrees and less than 90 degrees, or a1 and a2 are greater than 45 degrees and less than 90 degrees. In another embodiment, the second portion 1303 is perpendicular to the upper surface of the substrate 1010 and not inclined toward the light sensor 1013, while only the first portion 1301 is inclined toward the light sensor 1013. The annular wall connecting the first portion 1301 and the second portion 1303 may be disposed perpendicular to the upper surface of the substrate 1010 without inclination, and the inner wall thereof may be disposed with or without a reflective surface.

In addition, although fig. 13 shows the first portion 1301 and the second portion 1303 being substantially equal in height, the present invention is not limited thereto. In other embodiments, the first portion 1301 is higher (or longer) than the second portion 1303, similar to that shown in fig. 12 but with an oblique angle.

It should be noted that, although fig. 12 and 13 show the inner wall surface of the annular wall around the light source 1011 as a reflective surface (or mirror surface) to increase the intensity of the smoke reflected light S, the present invention is not limited thereto. In other embodiments, the inner wall surface of the annular wall may not be a reflective surface formed by additional treatment.

Fig. 14A-14C show cross-sectional views of a smoke detector 1400, 1400', 1400″ according to a fifth embodiment of the invention. The smoke detector 1400, 1400', 1400″ also includes a substrate 1010, a light source 1011, and a light sensor 1013. The light source 1011 and the light sensor 1013 are disposed on the upper surface of the substrate 1010, and are described above, so that they will not be described again.

The fifth embodiment is different from the fourth embodiment described above in that the fifth embodiment is configured such that the illumination range of the light source 1011 is shifted toward the light sensor 1013 by configuring the light guide element. Fig. 14A to 14C omit the cover 1003 in order to simplify the drawings.

In fig. 14A, the light guiding element includes a lens 1405 and a light reflecting member 1407. The lens 1405 is made of plastic or glass, for example. The optical axis of the lens 1405 is inclined toward the photosensor 1013 by an angle θ, which is preferably greater than 20 degrees and less than 45 degrees. The reflector 1407 is disposed at a side edge of the lens 1405 to prevent light leakage from the light source 1011 from the side edge of the lens 1405. In one embodiment, in response to the inclination of lens 1405, a first light reflecting portion of light reflecting member 1407 (right side of light source 1011 in fig. 14A) away from light sensor 1013 is higher than a second light reflecting portion of light reflecting member 1407 (left side of light source 1011 in fig. 14A) close to light sensor 1013. Meanwhile, the light guide element is disposed on the upper surface of the substrate 1010 and covers the light source 1011.

In fig. 14B, the light guiding element includes a lens 1405 'and a reflector 1407'. In this embodiment, the upper surface of the substrate 1010 is provided with a ring wall surrounding the light source 1011 and the light sensor 1013. As described above, the purpose of the annular wall is to control the illumination range of the light source 1011 and the light receiving range of the light sensor 1013. In fig. 14B, the light guide element is disposed on the annular wall around the light source 1011 and the optical axis of the lens 1405' is inclined toward the light sensor 1013 by the angle θ, so that the effect similar to that of fig. 14A can be achieved, i.e., the light intensity toward the right side wall of the housing (not shown) is reduced and the light intensity toward the light sensor 1013 is increased. It should be noted that the shape of the annular wall is not limited to that shown in fig. 14B.

It should be noted that, although fig. 14B shows that the light reflecting member 1407' is not disposed on the left side of the lens 1405', the present invention is not limited thereto, and the light reflecting member 1407' may be disposed on the left side of the lens 1405' if the thickness of the lens 1405' is larger or the inclination angle θ is smaller, similar to fig. 14A.

In addition, the embodiment of fig. 14A may be combined with fig. 12, for example, as shown in fig. 14C. In fig. 14C, smoke detector 1400 "includes a light guide element disposed on the upper surface of substrate 1010 and within the annular wall. In the present embodiment, the side edge of the lens 1405 may be provided with a reflective surface instead of a reflective member, on the inner wall surface of the annular wall around the light source 1011. Similar to fig. 12, a first portion 1401 of the annular wall that is farther from the light sensor 1013 (right side of the light source 1011 in fig. 14C) is higher than a second portion 1403 of the annular wall that is closer to the light sensor 1013 (left side of the light source 1011 in fig. 14C). Fig. 14C may be further combined with the embodiment of fig. 13, i.e. tilting the first portion 1401 of the annular wall towards the light sensor 1013. As for the second portion 1403 of the annular wall, as described in the fourth embodiment above, it may be maintained perpendicular to the upper surface of the substrate 1010 or inclined toward the photo sensor 1013.

Fig. 15A to 15B are cross-sectional views of smoke detectors 1500, 1500' according to a sixth embodiment of the invention. The smoke detector 1500, 1500' also includes a substrate 1010, a light source 1011, and a light sensor 1013, which are described above, and thus will not be described again here.

The sixth embodiment is to dispose a sub-substrate 1507 on the upper surface of the substrate 1010, wherein the sub-substrate 1507 is electrically connected to the substrate 1010 and the first surface (i.e. the upper surface) of the sub-substrate 1507 is inclined towards the optical sensor 1013 by an angle θ, which is preferably greater than 20 degrees and less than 45 degrees.

Note that although fig. 15A shows the cross section of the sub-substrate 1507 as a triangle, the present invention is not limited thereto. The cross section of the sub-substrate 1507 may be other shape as long as its upper surface is inclined toward the optical sensor 1013.

The sub-substrate 1507 may be a printed circuit board or a flexible substrate, and is not particularly limited as long as the light source 1011 can be coupled to the substrate 1010.

As shown in fig. 15A, by disposing the light source 1011 on the first surface of the sub-substrate 1507, similar effects to those of the fourth and fifth embodiments described above can be achieved as well.

Further, the embodiment of fig. 15A may be combined with the embodiment of fig. 12, as shown in fig. 15B. In fig. 15B, smoke detector 1500' has a ring wall disposed on the upper surface of substrate 1010 and surrounding sub-substrate 1507 and light source 1011. The purpose of the ring wall is as described above. A first portion 1501 of the annular wall around the light source 1011 (right side of the submount 1507 in fig. 15B) away from the photosensor 1013 is higher than a second portion 1503 of the annular wall (left side of the submount 1507 in fig. 15B) near the photosensor 1013, and at least an inner wall surface of the first portion 1501 is a reflective surface.

Furthermore, the embodiment of fig. 15A may also be combined with the embodiment of fig. 14A. That is, smoke detector 1500' further includes lens 1505 enveloping light source 1011 and the optical axis of lens 1505 is tilted toward light sensor 1013 by an angle θ2, which is preferably greater than 10 degrees and less than 20 degrees. Meanwhile, the inclination angle θ1 of the first surface of the sub-substrate 1507 is smaller than the inclination angle θ of fig. 15A, for example, greater than 10 degrees and less than 15 degrees. In other words, in fig. 15B, the effect of the tilt angle θ of the sub-substrate 1507 of fig. 15A is achieved by using the tilt angle θ1 of the sub-substrate 1507 and the tilt angle θ2 of the lens 1505 at the same time.

In summary, the smoke detectors of the fourth to sixth embodiments described above may be configured in combination, and are not limited to those shown in fig. 14C and 15B.

As described above, the known smoke detectors cannot be applied to different environments, such as indoor and outdoor environments, due to the fact that only a single threshold value is used, and the different kinds of smoke can generate different detection signals, so that the false alarm rate is high. Therefore, the present invention further provides a smoke detector with low false alarm rate (refer to fig. 1B, 3-4, 5A-5B, etc.), which can adjust the multiple condition thresholds used with respect to different specifications or the current detection results, so as to effectively reduce the false alarm rate. In addition, the smoke detector of the invention is additionally provided with a light guide structure which comprises a ring wall, a lens and/or a secondary substrate, so that the illumination range of the light source is offset towards the direction of the light sensor, and the false alarm rate is further reduced.

Although the invention has been disclosed by way of the foregoing examples, it is not intended to be limiting, but rather to limit the invention to the precise form disclosed, and that various other changes and modifications may be affected therein by one skilled in the art without departing from the scope or spirit of the invention. The scope of the invention is therefore intended to be defined only by the appended claims.

Claims (20)

1. A smoke detector, the smoke detector comprising:

a substrate;

a light source disposed on an upper surface of the substrate;

a photosensor disposed on the upper surface of the substrate; and

and a ring wall disposed on the upper surface of the substrate and surrounding the light source for shifting an illumination range of the light source toward the light sensor.

2. The smoke detector of claim 1, wherein,

the inner wall surface of the annular wall is a reflecting surface,

the annular wall is perpendicular to the upper surface, and

a first portion of the annular wall distal from the light sensor is higher than a second portion of the annular wall proximal to the light sensor.

3. The smoke detector of claim 2, wherein the height of the first portion is more than twice the height of the second portion.

4. The smoke detector of claim 1, wherein,

the inner wall surface of the annular wall is a reflecting surface, and

a first portion of the annular wall remote from the light sensor is inclined toward the light sensor.

5. The smoke detector of claim 4, wherein a second portion of the annular wall proximate the light sensor is perpendicular to the upper surface.

6. The smoke detector of claim 4, wherein a second portion of the annular wall proximate the light sensor is inclined toward the light sensor.

7. The smoke detector of claim 6, wherein the first portion has the same tilt angle as the second portion.

8. The smoke detector of claim 6, wherein the first portion has a different tilt angle than the second portion.

9. The smoke detector of claim 6, wherein the first portion is higher than the second portion.

10. A smoke detector, the smoke detector comprising:

a substrate;

a light source disposed on an upper surface of the substrate;

a photosensor disposed on the upper surface of the substrate; and

and a light guide element for shifting an illumination range of the light source toward the light sensor.

11. The smoke detector of claim 10, wherein the light guiding element comprises:

a lens having an optical axis inclined toward the photosensor; and

And the light reflecting piece is arranged at the side edge of the lens, and a first light reflecting part far away from the light sensor in the light reflecting piece is higher than a second light reflecting part close to the light sensor in the light reflecting piece.

12. The smoke detector of claim 11, wherein the tilt angle of the optical axis of the lens is greater than 20 degrees and less than 45 degrees.

13. The smoke detector of claim 10, wherein the light guide element is disposed on the upper surface of the substrate.

14. The smoke detector of claim 10, further comprising:

a ring wall disposed on the upper surface of the substrate and surrounding the light source, wherein,

the light guide element is configured on the annular wall.

15. The smoke detector of claim 10, further comprising:

a ring wall disposed on the upper surface of the substrate and surrounding the light source, wherein,

the light guide element is configured on the upper surface of the substrate and is positioned in the annular wall,

The inner wall surface of the annular wall is a reflecting surface, and

a first portion of the annular wall distal from the light sensor is higher than a second portion of the annular wall proximal to the light sensor.

16. The smoke detector of claim 10, further comprising:

a ring wall disposed on the upper surface of the substrate and surrounding the light source, wherein,

the light guide element is configured on the upper surface of the substrate and is positioned in the annular wall,

the inner wall surface of the annular wall is a reflecting surface, and

a first portion of the annular wall remote from the light sensor is inclined toward the light sensor.

17. A smoke detector, the smoke detector comprising:

a substrate;

a photosensor disposed on an upper surface of the substrate;

a sub-substrate disposed on the upper surface of the substrate and electrically connected to the substrate, wherein a first surface of the sub-substrate is inclined toward the light sensor; and

and a light source disposed on the first surface of the sub-substrate.

18. The smoke detector of claim 17, wherein the tilt angle of the first surface of the secondary substrate is greater than 20 degrees and less than 45 degrees.

19. The smoke detector of claim 17, further comprising:

a lens having an optical axis inclined toward the photosensor, wherein,

the first surface of the secondary substrate has an inclination angle of more than 10 degrees and less than 15 degrees, an

The tilt angle of the optical axis of the lens is greater than 10 degrees and less than 20 degrees.

20. The smoke detector of claim 17, further comprising:

a ring wall disposed on the upper surface of the base plate and surrounding the sub-base plate, wherein,

the secondary base plate is positioned in the annular wall,

the inner wall surface of the annular wall is a reflecting surface, and

a first portion of the annular wall distal from the light sensor is higher than a second portion of the annular wall proximal to the light sensor.