Smoke detector

Abstract

A smoke detector includes a substrate, a light source, and a light sensor. The light source and the light sensor are adjacently disposed on the substrate. An asymmetric structure is disposed on the substrate to offset an illumination area of the light source toward a position of the light sensor to improve a ratio of smoke reflected light to reference light intensity.

Description

Technical Field

[0001] This invention relates to a smoke detector, and more particularly to a smoke detector that can reduce false alarm rates and is applicable to different specifications. Background Technology

[0002] In current photoelectric smoke detectors, the light sensor does not receive any reflected light from the light source when there is no smoke. It only receives reflected or scattered light when smoke enters the detector. Furthermore, the inner surface of the smoke detector is coated with a light-absorbing material to prevent internal reflection from the light sensor when no smoke is present. However, when a sufficient amount of dust accumulates inside the smoke detector, light can be reflected internally and received by the light sensor, causing a false alarm.

[0003] The operating mechanism of a scattering smoke detector is that an alarm is triggered when the intensity of the scattered light produced by the smoke on the light source exceeds a single alarm threshold.

[0004] However, since the interaction between smoke and light produced by different types of flames is different—for example, smoldering ash smoke can produce several times more scattered light than burning black smoke—setting a single alarm threshold will make smoke detectors too sensitive to certain types of smoke, thus easily generating false alarms, while not sensitive enough to other types of smoke, thus delaying the alarm timing.

[0005] In addition, the environment typically contains many sources of interference, such as humidity, water vapor, cooking fumes, cigarette smoke, dust, and insects, all of which can alter the intensity of reflected light signals and cause false alarms. These factors contribute to the relatively high false alarm rate of smoke detectors currently on the market, and the only way to reduce false alarms is through passive means, such as avoiding installing smoke detectors in places with too many interference sources (e.g., kitchens, bathrooms, garages), but there is no complete and effective solution. Summary of the Invention

[0006] In view of this, the present invention provides a smoke detector that can effectively reduce the false alarm rate and is adaptable to different specifications.

[0007] The present invention provides a smoke detector including a light sensor, which can still detect reference light energy as a reference for judging the occurrence of a fire when no smoke enters the detection space of the smoke detector.

[0008] The present invention also provides a smoke detector that can avoid the light reflected from accumulated dust being detected by the optical sensor, thereby reducing the false alarm rate.

[0009] The present invention also provides a smoke detector that can automatically adjust multiple condition thresholds based on the detection results of an optical sensor to reduce the false alarm rate.

[0010] The present invention also provides a smoke detector in which the illumination range of the light source is offset toward the light sensor to increase the intensity of scattered light.

[0011] This invention provides a smoke detector comprising a substrate, a light source, a light sensor, and a surrounding wall. The light source and the light sensor are disposed on the upper surface of the substrate. The surrounding wall is disposed on the upper surface of the substrate and surrounds the light source, thereby shifting the illumination range of the light source toward the light sensor.

[0012] The present 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 to shift the illumination range of the light source toward the light sensor.

[0013] The present 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 disposed on the upper surface of the substrate and electrically connected to the substrate, and a first surface of the secondary substrate is inclined toward the light sensor. The light source is disposed on the first surface of the secondary substrate.

[0014] To make the above and other objects, features and advantages of the present invention more apparent, a detailed description will be provided below with reference to the accompanying drawings. Furthermore, in the description of the present invention, the same components are denoted by the same reference numerals, which will be stated herein as well. Attached Figure Description

[0015] Figure 1A This is a perspective view of the smoke detector housing according to the first embodiment of the present invention;

[0016] Figure 1B This is a cross-sectional view of the smoke detector according to the first embodiment of the present invention;

[0017] Figure 1C This is another cross-sectional view of the smoke detector according to the first embodiment of the present invention;

[0018] Figure 2 This is a perspective view of the smoke detector housing according to the second embodiment of the present invention;

[0019] Figure 3 This is a cross-sectional view of a smoke detector according to a second embodiment of the present invention, wherein the cover is Figure 2 A cross section along line A-A';

[0020] Figure 4 This is a side view of a modified example of the smoke detector according to the second embodiment of the present invention;

[0021] Figure 5AThis is a schematic diagram of the detection element of the smoke detector according to the third embodiment of the present invention;

[0022] Figure 5B This is a cross-sectional view of a smoke detector according to a third embodiment of the present invention;

[0023] Figure 6 This is a schematic diagram of the different contours of the detection signal and different types of smoke relative to multiple preset condition thresholds of the smoke detector in an embodiment of the present invention;

[0024] Figures 7A-7C This is a schematic diagram of the detection signals of different types of smoke detected by the smoke detector in an embodiment of the present invention;

[0025] Figures 8A-8C This is a schematic diagram of the detection signals of different detectors detected by the smoke detector in an embodiment of the present invention;

[0026] Figure 9 This is a schematic diagram of the operation of a smoke detector according to an embodiment of the present invention, showing that the smoke detector has a variable detection frequency;

[0027] Figure 10A and Figure 10B This is a schematic diagram of light transmission within a smoke detector according to an embodiment of the present invention;

[0028] Figure 11 This is a graph showing the relationship between the intensity of the detected scattered light from the smoke detector in this embodiment of the invention and different light source shading ratios and light source assembly offsets;

[0029] Figure 12 and Figure 13 This is a cross-sectional view of the smoke detector according to the fourth embodiment of the present invention;

[0030] Figures 14A to 14C This is a cross-sectional view of the smoke detector according to the fifth embodiment of the present invention; and

[0031] Figure 15A and Figure 15B This is a cross-sectional view of the smoke detector according to the sixth embodiment of the present invention.

[0032] Explanation of reference numerals in the attached figures

[0033] 1200, 1300, 1400, 1500 smoke detectors

[0034] 1001 Detection Element

[0035] 1010 base plate

[0036] 1011 Light Source

[0037] 1013 Light Sensor

[0038] 1003 Cover

[0039] 1201, 1301, 1401, 1501 First side wall

[0040] 1203, 1303, 1403, 1503 Second side wall

[0041] 1405, 1405', 1505 lenses

[0042] 1407, 1407' Reflectors

[0043] 1507 sub-substrate Detailed Implementation

[0044] The smoke detector of this invention includes a processor with a built-in classifier that can identify different types of smoke and dust and adjust the alarm threshold based on the detection results to reduce the false alarm rate. Furthermore, the smoke detector of this invention utilizes protruding structures to shield the scattered and reflected light from accumulated dust, and / or employs multiple light sources to identify the types of interfering substances. These interfering substances include, for example, smoke, dust, water vapor, and accumulated dust.

[0045] Please refer to Figures 1A to 1C As shown, Figure 1A This is a perspective view of the cover 12 of the smoke detector 100 according to the first embodiment of the present invention; Figure 1B This is a cross-sectional view of the smoke detector 100 according to the first embodiment of the present invention; Figure 1C This is another cross-sectional view of the smoke detector 100 according to the first embodiment of the present invention, which shows that smoke enters the detection space of the smoke detector 100 and increases the amount of reflectivity.

[0046] The smoke detector 100 includes a detection element 11 and a cover 12, which covers the detection element 11 so that the detection element 11 is located within the interior space of the cover 12 (serving as the detection space). For example, the detection element 11 is disposed on a base 10 with an area greater than or equal to that of the cover 12, one side of which is attached to the cover 12 and the other side is fixed to the wall or ceiling where the smoke detector 100 is to be installed. The material of the base 10 is not specifically limited, and can be, for example, plastic, glass, wood, etc.

[0047] The enclosure 12 includes a reflective surface 120 and a sidewall 121, the sidewall 121 extending from or near the edge of the reflective surface 120, for example... Figure 1B and Figure 1CThe sidewall 121 extends perpendicularly from the reflective surface 120 in the configuration direction toward the detection element 11, but the present invention does not limit the sidewall 121 to be perpendicular to the reflective surface 120; for example, it may have an angle. To allow air (and smoke if present) to enter the interior space of the smoke detector 100, the sidewall 121 has perforations. For example, Figure 1A The sidewall 121 includes a plurality of pillars extending from the edge of the reflective surface 120, separated from each other, with the spacing between the pillars serving as apertures. To prevent external light from entering the interior space of the smoke detector 100 and affecting its detection capability, the sidewall 121 is preferably configured so that the interior space is not directly visible from the outside of the enclosure 12, but the shape of the pillars is not limited to this configuration. Figure 1A As shown. The reflective surface 120 is used to reflect the emitted light from the light source 111.

[0048] In another embodiment, the sidewall 121 extends from the base 10 (e.g. Figure 1B and Figure 1C Below the base 10, the cover 12 is a flat plate without side walls. The cover 12 is attached to the top of the side wall 121 of the base 10 to enclose the detection space of the smoke detector 100.

[0049] In another embodiment, the base 10 and the cover 12 each have sidewalls 121 and are opposite to each other. The cover 12 encloses the detection space of the smoke detector 100 by combining the top of the sidewalls 121 of the base 10 and the cover 12. The cover 12 can be attached to the base 10 by adhesive or fasteners, and there are no particular limitations.

[0050] The detection element 11 includes a light source 111, a light sensor 113, and a processor 13, which are 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.

[0051] The smoke detector of this embodiment is configured such that, even when no smoke enters its interior space, the light sensor can still receive a reference light intensity to generate a reference detection signal Sdr. The light source 111 preferably uses a non-coherent light source, such as a light-emitting diode (LED). The light source 111 emits a main beam ELm toward the reflective surface 120 to generate a main reflected beam RLm reflected from the reflective surface 120, where the main beam ELm refers to the light within the emission angle of the light source 111. In other embodiments, if the light source 111 is equipped with optical elements to diffuse the emission angle of the light source 111, the light source 111 may also use a laser diode.

[0052] The light sensor 113 is, for example, a CMOS image sensor, a photodiode, or a single-photon breakdown diode (SPAD), which detects reflected light (including at least a portion of the main reflected beam RLm) from the reflective surface 120 at a predetermined frequency to generate a detection signal. For example, the light sensor 113 is disposed in or near the optical path of the main reflected beam RLm, but is not limited thereto.

[0053] Processor 13 is, for example, a microprocessor (MCU) or an application-specific integrated circuit (ASIC). Processor 13 receives a reference detection signal Sdr generated by time sensor 113 when no smoke enters or obstructs the main reflected beam RLm (e.g., ...). Figure 1B (as shown) and receives the current detection signal Sdc generated by the time sensor 113 when smoke enters or blocks the main reflected beam RLm (as shown). Figure 1C (As shown). In one embodiment, the magnitude of the reference detection signal Sdr is determined based on the spatial relationship between the light source 111, the light sensor 113, the sidewall 121 and the reflective surface 120, and the reflectivity of the reflective surface 120.

[0054] The processor 13 determines whether to issue an alarm based on the ratio of the current detection signal Sdc to the reference detection signal Sdr, such as Sdc / Sdr or (Sdc-Sdr) / Sdr. Figure 1C As shown, when smoke 80 enters the internal space (intervening in the path of the main reflected beam RLm), the light sensor 113 simultaneously detects the reflected light RLm1 (reflected by the reflecting surface 120) and RLm2 (reflected by smoke 80), resulting in Sdc > Sdr, where Sdc is mainly... Figure 1C It is generated by the sum of RLm1 and RLm2, and Sdr is mainly generated by the sum of RLm1 and RLm2. Figure 1B The RLm is generated. For example, when the signal ratio (or normalized strength) of Sdc / Sdr or (Sdc-Sdr) / Sdr exceeds a predetermined value, for example... Figure 9 As shown in TH2, processor 13 controls a speaker or a host computer (not shown) to emit an alarm sound. For example, smoke detector 100 itself or the host computer has a speaker. Figure 9 The normalized strength is calculated as Sdc / Sdr.

[0055] More specifically, in the first embodiment, when the light source 111 and the light sensor 113 are positioned at approximately the same height in the internal space, the light source 111 and the light sensor 113 are symmetrically arranged on both sides of the reflection position relative to the reflection surface 120, for example... Figure 1BThe left and right sides. It can be understood 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 arranged on both sides of the reflection position. For example, the light sensor 11 is arranged in the area where the reflected light is strongest.

[0056] In another embodiment, the light sensor 113 is positioned near (but not at) the region receiving the strongest reflected light to avoid the reference detection signal Sdr being too high and reducing the sensitivity of the light sensor 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.

[0057] Please refer to Figures 2 to 4 As shown, Figure 2 This is a perspective view of the cover 32 of the smoke detector 300 according to the second embodiment of the present invention; Figure 3 This is a cross-sectional view of the smoke detector 300 according to the second embodiment of the present invention, wherein the cover 32 is Figure 2 A cross section along line A-A'; Figure 4 This is a schematic diagram of a modified example of the smoke detector 300 according to the second embodiment of the present invention.

[0058] The smoke detector 300 also includes a detection element 31 and a cover 32, which covers the detection element 31 so that the detection element 31 is located in the internal space of the smoke detector 300 (as the detection space). Similarly, the detection element 31 is disposed on a base 30 with an area greater than or equal to that of the cover 32, and the base 30 can be combined with the cover 32 and fixed to the wall or ceiling where the smoke detector 300 is to be installed. Likewise, there are no specific limitations on the material of the base 30.

[0059] In the second embodiment, the configuration of the detection element 31 is the same as that of the detection element 11 in the first embodiment, only different numbers are used for identification. The light sensor 313 is used to receive the reflected light RL1 of the emitted light beam EL of the light source 311 to generate a detection signal Sd. The difference between the second embodiment and the first embodiment lies in the structure of the cover 32.

[0060] The cover 32 includes a bottom surface 320 and side walls 321, which are identical to the side wall 121 in the first embodiment, extending from the edge of the bottom surface 320 and having openings. For example, the side wall 121 includes a plurality of separate columns extending from the edge of the bottom surface 320. Similar to the first embodiment, depending on the implementation, the side wall 321 is disposed on the base 30, or simultaneously on the bottom surface 320 and the base 30.

[0061] In the second embodiment, the bottom surface 320 also has a plurality of protrusions 323 extending from the bottom surface 320, the plurality of protrusions 323 being used to block reflected light RL2 reflected from the bottom surface 320 (or dust 90, if accumulated). Figure 3 As shown, the light sensor 313 primarily receives reflected light RL1 from the upper surfaces of the multiple protrusions 323 to generate a detection signal Sd. Therefore, even if dust 90 accumulates on the bottom surface 320, most of the reflected light RL2 reflected by the dust 90 is blocked by the multiple protrusions 323 and will not be received by the light sensor 313. Therefore, whether or not dust 90 accumulates on the bottom surface 320 does not affect the reference value (i.e., the reference detection signal) of the detection signal Sd.

[0062] As mentioned above, this invention is based on the current value of the detection signal Sd (i.e., the current detection signal) and the reference value of the detection signal Sdr (…). Figure 1B The signal ratio (similar to when no smoke enters the detection space), such as Sd / Sdr or (Sd-Sdr) / Sdr, is used to determine whether to issue an alarm. According to the configuration of the second embodiment, since the reference value of the detection signal Sdr is not affected by accumulated dust 90, the false alarm rate can be effectively reduced.

[0063] It must be noted that, although Figure 2 The multiple protrusions 323 shown are elongated and parallel to each other, and are for illustrative purposes only and not for limiting the invention. In other embodiments, the multiple protrusions 323 may be cylinders, triangular prisms, rectangular prisms, or combinations thereof that are separated from each other and arranged in an alternating manner, without any particular limitation, as long as they can block the reflected light RL2. In addition, the height of the multiple protrusions 323 can 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, as long as the multiple protrusions 323 can block the reflected light RL2, without any particular limitation.

[0064] In addition, although Figure 3 The invention displays multiple elongated protrusions 323 extending across the entire bottom surface 320, but this is not a limitation. In other embodiments, the multiple protrusions 323 may be configured only within the illumination range of the main optical path of the light source 311. In yet another embodiment, parallel elongated protrusions 323 are provided within the illumination range of the main optical path of the light source 311, while elongated protrusions 323 extending in different directions are provided in other areas of the bottom surface 320.

[0065] Please refer to again Figure 3As shown, in one embodiment, the light source 311 and the light sensor 313 are disposed opposite the bottom surface 320, and a plurality of protrusions 323 are used to shield the bottom surface 320 from reflecting the reflected light RL2 of the emitted light beam EL of the light source 311. As previously mentioned, when dust 90 accumulates on the bottom surface 320, the reflected light RL2 is reflected by the dust 90. When the plurality of protrusions 323 are elongated, the direction of extension of the elongation is opposite to the direction of the transverse component of the emitted light beam EL of the light source 311 (e.g., the direction of the transverse component). Figure 3 (Vertical in the left and right directions) to effectively block reflected light RL2.

[0066] Please refer to Figure 4 The image shows a side view of a modified example of the smoke detector 400 according to the second embodiment of the present invention. In another embodiment, the housing 32 further includes a reflective surface 422 disposed on the inner surface of the side wall 421, and the light source 411 and the light sensor 413 are also disposed on the inner surface of the side wall 421 and located opposite the reflective surface 422. Similar to the first embodiment, depending on the application, the side wall 421 extends upward from the housing or downward from the base. In this embodiment, the reflective surface 422 is not located on the bottom surface 420 of the housing, and the material of the reflective surface 422 is not specifically limited, as long as it can reflect the emitted light beam EL of the light source 411.

[0067] More specifically, in this embodiment, the light source 411 does not project the emitted light beam EL toward the plurality of protrusions 423. Since the light sensor 413 receives reflected light from the bottom surface 420 (without the protrusions 423) to varying degrees during operation, the accumulation of dust 90 on the bottom surface 420 increases the reference value of the detection signal. Therefore, this embodiment also reduces the impact of accumulated dust 90 on the reference value of the detection signal Sd by providing multiple protrusions 423 on the bottom surface 420, thereby reducing the false alarm rate. The multiple protrusions 423 and... Figure 3 The multiple protrusions 323 are the same, so they will not be described in detail here.

[0068] To elaborate further, Figure 4 and Figure 3 The difference lies in the placement of the light source and the light sensor. Figure 4 This configuration allows the emitted beam EL and the reflected beam RL1 to propagate above multiple protrusions 423. It is understood that... Figure 4 The smoke detector 400 also includes a processor electrically connected to the light sensor 413 to process the detection signal from the light sensor 413.

[0069] Please refer to Figure 5A and Figure 5B As shown, Figure 5A This is a schematic diagram of the detection element 51 of the smoke detector 500 according to the third embodiment of the present invention; Figure 5BThis is a cross-sectional view of a smoke detector 500 according to a third embodiment of the present invention. The smoke detector 500 also includes a detection element 51 and a cover 52, wherein the cover 52 can also be combined with the base 50 to form a detection space, as has been described above, and will not be described again here.

[0070] It must be noted that, although Figure 5B The display cover 52 is the same as the cover 12 in the first embodiment. In other embodiments, the cover 52 may also be the same as the cover 32 in the second embodiment, without any specific limitation. More specifically, the difference between the third embodiment and the first and second embodiments described above lies mainly in the component configuration of the detection element 51.

[0071] The detection element 51 includes a light sensor 513, a processor 53, a first light source 511 (or 512), and a second light source 511' (or 512'). Similar to the first embodiment, the light sensor 513 can be a CMOS image sensor, a photodiode, or a SPAD, without specific limitations. The light sensor 513 is used to detect scattered and reflected light from the enclosure 52, smoke 80, or suspended dust 90' when different light sources are lit to generate a detection signal, such as a light intensity signal.

[0072] 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 are not limited to this wavelength. The first light source 511 and the second light source 511' can be co-modulated or non-co-modulated light sources, without specific limitations, and are respectively disposed on opposite sides of the light sensor 513, and preferably at the same distance from the light sensor 513, for example... Figure 5A The first light source 511 is positioned to the left of the light sensor 513, while the second light source 511' is positioned to the right of the light sensor 513. Preferably, a light-blocking wall is disposed between the light sensor 513 and the light sources 511 and 511'.

[0073] The processor 53, such as a microprocessor or an application-specific integrated circuit, is used to receive 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 at different times, so 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 Sd1.

[0074] The processor 53 distinguishes between smoke 80 and suspended dust 90' based on the similarity between the first detection signal Sd1 and the second detection signal Sd2. For example, when the difference or standard deviation between the first detection signal Sd1 and the second detection signal Sd2 is smaller than a 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 dissimilar to each other.

[0075] For example, refer to Figure 5B As shown, when the first light source 511 and the second light source 511' are lit sequentially, the processor 53 sequentially receives the first detection signal Sd1 and the second detection signal Sd2. When smoke 80 enters the internal space (i.e., the detection space) of the smoke detector 500, the smoke 80 is usually uniformly distributed within the enclosure 52. Therefore, the intensities of the first reflected light RL1 and the second reflected light RL2 are approximately the same, resulting in the normalized intensities (Sd1-Sdr1) / Sdr1 and (Sd2-Sdr2) / Sdr2 (or Sd1 / Sdr1 and Sd2 / Sdr2) being approximately the same. Here, Sdr1 is the first detection signal (or the first reference detection signal) when no smoke or dust enters the detection space, and Sdr2 is the second detection signal (or the second reference detection signal) when no smoke or dust enters the detection space. Intensity normalization of the detection signals is used to eliminate the effect of light emission attenuation of the light sources 511 and 511'.

[0076] However, when dust 90' enters the enclosure 52, due to the wind direction and small quantity, the dust 90' may not be evenly distributed within the enclosure 52. Therefore, the intensities of the first reflected light RL1 and the second reflected light RL2 are different, resulting in different first detection signals Sd1 and second detection signals Sd2. Therefore, the processor 53 can distinguish the interference caused by suspended dust 90' and reduce the false alarm rate by arranging light sources of the same wavelength on different sides of the light sensor 513. In this way, the processor 53 can identify the intensity changes of smoke 80 and suspended dust 90'.

[0077] It must be noted that, although Figure 5A Displays 511 and 511' are symmetrical about the light sensor 513 (both are spaced d apart), and 512 and 512' are symmetrical about the light sensor 513 (both are spaced d apart), but the present invention is not limited thereto. In other embodiments, 511' is positioned at the location of 512' or 511 is positioned at the location of 512, that is, with Figure 5A The horizontal direction is not parallel.

[0078] Furthermore, in the third embodiment, light sources of different wavelengths can be configured on the same side of the light sensor 513. For example, a third light source 512 can be configured on the same side of the light sensor 513 as the first light source 511, or a third light source 512' can be configured on the same side of the light sensor 513 as the second light source 511', or two third light sources 512 and 512' can be configured on opposite sides of the light sensor 513. The wavelength of the light emitted by the third light source 512 (or 512') is different from the wavelength of the light emitted by the first light source 511 and the second light source 511'. In this embodiment, the processor 53 also receives a third detection signal Sd3 from the light sensor 513 when the third light source 512 and / or 512' emits light (not simultaneously with the first light source 511 and the second light source 511'). The processor 53 determines the type of smoke or dust based on the characteristic value relationship between the normalized intensity (Sd1-Sdr1) / Sdr1 (or normalized intensity (Sd2-Sdr2) / Sdr2) and the normalized intensity (Sd3-Sdr3) / Sdr3, where Sdr3 is the third detection signal (or the third reference detection signal) when no smoke or dust enters the detection space.

[0079] For example, refer to Figures 7A to 7C As shown, although the 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 changes (or trends) in the light intensity of the first detection signal Sd1 and the third detection signal Sd3 are similar. Therefore, the processor 53 can identify whether the interfering object is smoke 80 based on the characteristic values ​​of the detection signals Sd1 and Sd3. The characteristic values ​​include, but are not limited to, the normalized intensity values ​​of the first detection signal Sd1 and the third detection signal Sd3, the moving average over time, the slope, the standard deviation, the peak spacing, and the type of filter used.

[0080] Therefore, when the light intensity changes of the first detection signal Sd1 and the third detection signal Sd3 are different (or their characteristic values ​​are different), the processor 53 determines that the interfering object is suspended dust 90' due to low similarity; while when the light intensity changes of the first detection signal Sd1 and the third detection signal Sd3 are approximately the same (or their characteristic values ​​are the same), the processor 53 determines that smoke 80 has entered the internal space due to high similarity. In this way, the smoke detector 500 can eliminate the interference caused by dust 90', thereby reducing the false alarm rate.

[0081] In the above judgment method, if the third light source 512' is configured next to the second light source 511', the processor 53 compares the feature values ​​of the second detection signal Sd2 and the third detection signal Sd3 to distinguish between smoke and suspended dust.

[0082] Furthermore, the processors (including 13, 33, and 53) of the smoke detectors (including 100, 300, 400, and 500) in various embodiments of the present invention are also used to select a set of condition thresholds from multiple sets of preset condition thresholds based on the profile of the current detection signal generated by the optical sensor (including 113, 313, 413, and 513) or the aforementioned feature values, and compare them with the current detection signal to determine whether to issue an alarm.

[0083] For example, refer to Figure 6 As shown, it displays the contours (contours 1 to 4) of different detection signals and different smoke types (type 1 to type 4), each with a preset set of conditional 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 for different feature values. In this invention, the smoke detector issues an alarm when each set of conditional thresholds is simultaneously satisfied.

[0084] In one embodiment, when the smoke detector of this invention contains only a single wavelength light source, the processor determines the light source based on the current detection signal, for example... Figures 7A to 7C Sd3 is used to set or select a set of conditional thresholds currently in use. For example, when the processor determines that the slope of the current normalization intensity (Sd3-Sdr3) / Sdr3 or Sd3 / Sdr3 is greater than B1, the relative... Figure 6 A set of preset threshold conditions for contour 1 are selected; therefore, when the current normalized intensity (Sd3-Sdr3) / Sdr3 or the intensity of Sd3 / Sdr3 is greater than A1, the smoke detector issues an alarm. However, before issuing an alarm during detection, when the processor further determines that the slope of the current normalized intensity (Sd3-Sdr3) / Sdr3 or Sd3 / Sdr3 is greater than B2 (e.g., B2>B1), the relative... Figure 6 A set of preset threshold conditions for contour 2 is selected; therefore, when the current normalized intensity (Sd3-Sdr3) / Sdr3 or the intensity of Sd3 / Sdr3 is greater than A2, the smoke detector issues an alarm. In other words, during operation, when the processor determines that the contour of the detection signal changes over time, the smoke detector of this embodiment actively selects from multiple sets (e.g., Figure 6 (Displayed as 4 groups, but not limited to) Select another group of condition thresholds from the preset condition thresholds. In this way, the condition thresholds can be dynamically changed according to the actual situation to reduce the false alarm rate.

[0085] It must be noted that, although Figure 6 The invention can display multiple sets of preset threshold conditions, but it is not limited to this. In other embodiments, the smoke detector may have multiple preset threshold condition ranges (i.e., including upper and lower thresholds) built-in (in memory).

[0086] In one embodiment, when the smoke detector of this invention includes two light sources with different wavelengths (i.e., different dominant wavelengths), each set of preset condition thresholds may further include the signal ratio (or characteristic ratio) of the detection signals of the different wavelengths. For example, when the processor determines that the slope of the current normalized intensity (Sd3-Sdr3) / Sdr3 or Sd3 / Sdr3 is greater than B1, an alarm will only be issued when the intensity of the current normalized intensity (Sd3-Sdr3) / Sdr3 or Sd3 / Sdr3 is greater than A1 and the signal ratio (or characteristic ratio) of the detection signals of the two wavelengths (e.g., Sd3 and Sd1) or the normalized intensity is less than C1.

[0087] It should be noted that there is no specific limit to the number of condition thresholds in a set of preset condition thresholds.

[0088] In this invention, multiple sets of preset threshold conditions are stored in the processor's memory, for example. Users can also change the multiple sets of preset threshold conditions as needed, for example, by selecting different sets of preset threshold conditions relative to different national standards (e.g., including UL268 and UL217 in the United States; EN1464 and EN54 in Europe, but not limited to) and different setting environments (e.g., indoor or outdoor). More specifically, the smoke detector of this invention has multiple sets of selectable or changeable preset threshold conditions built into it to correspond to different operating environments.

[0089] In addition, such as Figures 7A to 7C As shown, because the smoke produced by paper fire, wood fire, and foam fire is different, the detection signals will also be different, leading to differences in the relationship between the aforementioned feature values. The processor in this embodiment of the invention can also select different sets of condition thresholds from multiple preset condition thresholds based on different smoke types. For example, the processor in this embodiment of the invention has a built-in classifier, 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, and Sd3), it first classifies the current smoke type based on the feature value of one detection signal or the relationship between the feature values ​​of two detection signals. Then, the processor selects the smoke type (e.g., ... Figure 6 The set of preset condition thresholds corresponding to categories 1 to 4 shown. Figures 7A to 7C In the diagram, the vertical axis represents the normalized intensity value of the detected signal. For example, the processor first calculates the average signal value over a predetermined period (e.g., 10 seconds) at the start of operation as a reference value. Then, it divides the current detected signal value during operation by this reference value minus 1 (as the normalized intensity value), thus obtaining the normalized intensity value. Figures 7A to 7C The detection signals from Sd1 to Sd3.

[0090] Figure 6In the context of "period 1 to period 4", it refers to a time interval, indicating that all preset condition thresholds must be met within the predetermined time interval before an alarm will be issued.

[0091] It must be noted that, although Figure 6 The invention displays a set of preset threshold conditions corresponding to the smoke type and the contour of the detection signal, but this is not limited to this. In other embodiments, the smoke type and the contour of the detection signal may correspond to completely different sets of preset threshold conditions. That is, the smoke type and the contour of the detection signal determine different sets of threshold conditions.

[0092] In addition to identifying different types of smoke, the smoke detector in this embodiment of the invention can also distinguish whether the smoke is produced by a flame, thus altering the detection signal. For example... Figures 8A to 8C As shown, the contours (or intensity changes) of the detection signals caused by smoke, dust, and water vapor are all different. The processor in this embodiment of the invention identifies signal changes in the detection signal (e.g., Figure 9 When the signal profile is greater than TH1, the built-in classifier first determines whether the profile of the signal change is caused by a flame. For example, if the classifier identifies that the profile of the detected signal is caused by dust, water vapor, or other non-flame-related factors, the processor does not compare the characteristics of the detected signal with any set of preset condition thresholds to avoid issuing false alarms. If the classifier identifies that the profile of the detected signal is caused by a flame, the processor then selects a set of preset condition thresholds suitable for the current situation (determined by the characteristic value of the current detected signal) and compares them with subsequent detection values ​​to determine whether to issue an alarm.

[0093] Furthermore, the smoke detectors (including 100, 300, 400, and 500) of this invention can also change the detection frequency according to the current detection signal to shorten the reaction time. For example, see reference. Figure 9 As shown, initially (when the detection signal does not change significantly), the smoke detector's optical sensor generates a detection signal at a first detection frequency. When the processor determines that the normalized intensity value of the detection signal is greater than or equal to a first threshold TH1, indicating a possible fire, the processor controls the optical sensor to increase to a second detection frequency (while simultaneously increasing the flashing rate of the light source). An alarm is only issued when the processor determines that the normalized intensity value of the detection signal is greater than or equal to a second threshold TH2.

[0094] It must be noted that, although Figure 9 The condition for issuing an alarm is described as the normalized intensity value exceeding the second threshold TH2, but the present invention is not limited to this. In other embodiments, the condition for issuing an alarm may be as follows: Figure 6 The condition is established only if all the preset threshold conditions shown are met.

[0095] Similarly, the first threshold TH1 can be replaced by a set of preset threshold conditions, rather than a single condition. At the same time, the first threshold TH1 and the second threshold TH2 can also be dynamically and actively changed according to specifications, the current detection signal, and the type of smoke, as mentioned above, rather than requiring user adjustment or being fixed values.

[0096] It must be stated that, Figures 7A-7C , Figures 8A-8C and Figure 9 The detection signal mentioned in the relevant description can be the detection signal mentioned in the first to third embodiments described above. In other words, the processors in the first to third embodiments can all select a set of preset condition thresholds, identify interfering objects, and / or adjust the sampling frequency based on the current detection signal.

[0097] In this invention description, "particle" refers to a substance that floats in the air, while "dust" refers to a substance that accumulates at the bottom of the enclosure, for ease of explanation.

[0098] In this invention description, the normalized intensity value can be as follows: Figure 9 The result is calculated based on (current detection value / reference detection value), or as shown below. Figures 8A-8C and Figure 9 The result is calculated based on (current detection value / reference detection value) - 1.

[0099] In this invention, in order to distinguish between smoke, dust, and particulate matter, when determining the type of smoke and deciding whether to issue a warning, the processor first normalizes the current detection signal with a reference detection signal to eliminate the influence of light source attenuation.

[0100] As described above, optical smoke detectors can be configured to issue an alarm based on the ratio of the current detection signal Sdc to the reference detection signal Sdr, for example, (Sdc-Sdr) / Sdr, where (Sdc-Sdr) can be referred to as the scattered light intensity. However, the reference detection signal Sdr can change with variations in ambient temperature and component assembly position, leading to false alarms. By increasing the ratio of the current detection signal Sdc to the reference detection signal Sdr, the incidence of false alarms can be reduced.

[0101] Please refer to Figure 10A and Figure 10B This is a schematic diagram of light transmission within a smoke detector 1000 according to certain embodiments of the invention. Figure 10A The smoke detector 1000 includes an optomechanical structure 1001 and a housing 1003.

[0102] The optomechanical structure 1001 emits light from the light source 1011, illuminating the internal space of the enclosure 1003 and the suspended particles (e.g., smoke, represented by dots not on the inner surface) within the enclosure 1003. It is assumed that the reflected light intensity at each point on the inner surface is 10S (detected by the light sensor 1013), and that suspended particles at different locations have different reflected light intensities, for example, shown as 0S, 1S, 3S, 7S, and 8S, but not limited to these. In this case, the ratio of the total reflected light intensity 19S (or scattered light intensity) of the suspended particles to the total reflected light intensity 50S of the inner surface (i.e., the reference light intensity used to generate the detection signal) is 0.38. Figure 10B The smoke detector 1000 is further equipped with a light-blocking component 1002, which blocks part of the emission angle of the light source 1011, so that only a portion of the interior of the enclosure 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 is 0.75. That is, by configuring the light-blocking component 1002, the ratio of smoke reflected light intensity to reference light intensity can be significantly increased, thereby improving the detection sensitivity of the smoke detector 1000.

[0103] However, the proportion by which the light-blocking component 1002 blocks the light source 1011 is not without limitations. Since both the reference light intensity and the scattered light intensity are used to determine whether to issue an alarm, if the reference light intensity is too low, the scattered light intensity will also vary significantly with different conditions.

[0104] For example, refer to Figure 11 As shown, it displays the fluctuation of scattered light intensity caused by different offset positions of the light source 1011 (e.g., b=0 indicates no offset; b=negative indicates offset closer to the light sensor 1013; b=positive indicates offset farther from the light sensor 1013) under different shading ratios a (e.g., a=0 indicates no shading; a=1 indicates complete shading) of the light source 1011. Figure 11 The vertical axis represents light intensity. From Figure 11 It can be seen that when the shading ratio of the light source 1011 is between 10% and 40% (i.e., a = 0.1 to 0.4), the intensity of scattered light is less affected by the different positional offsets of the light source 1011. Figure 11 In this context, the preferred shading ratio is 25%, that is... Figure 10B The middle light-blocking component 1002 blocks the right 1 / 4 of the light source 1001.

[0105] The purpose of configuring the light-blocking element 1002 is to reduce the intensity of the reference light. However, it can be noted that the same purpose can also be achieved by increasing the intensity of the scattered light. The optical smoke detectors of other embodiments of the present invention described below can also achieve the same effect as configuring the light-blocking element 1002, namely, increasing (Sdc-Sdr) / Sdr. In the accompanying drawings of the following embodiments, the processor that performs the above functions is omitted.

[0106] Please refer to Figure 12 and Figure 13 The diagram shows a cross-sectional view of smoke detectors 1200 and 1300 according to a fourth embodiment of the present invention. Smoke detectors 1200 and 1300 include an optomechanical structure 1001 and a housing 1003, wherein the housing 1003 has been described above and will not be repeated here.

[0107] The optomechanical structure 1001 includes a substrate 1010, a light source 1011, and a photosensor 1013, wherein the light source 1011 and the photosensor 1013 are disposed on the upper surface of the substrate 1010. The substrate 1010 can be a printed circuit board (PCB) or a flexible substrate, and there is no specific limitation. The light source 1011 and the photosensor 1013 are the same as the light source 111 and the photosensor 113 in the above embodiment, and therefore will not be described again here.

[0108] 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 photosensor 113. The ring wall is made of an opaque material and is used to define the illumination range of the light source 1011 and the light receiving range of the photosensor 113. The ring wall prevents the light emitted by the light source 1011 from being directly transmitted to the photosensor 113. In this embodiment, the ring wall is also configured to offset the illumination range of the light source 1011 toward the photosensor 1013. For example, the right wall of the cover 1003 in the figure is not illuminated by the light source 1011, so as to reduce the intensity of the reference light (e.g., shown as R) and increase the intensity of the reflected light (i.e., the scattered light intensity, e.g., shown as S) of the smoke 90.

[0109] In this embodiment, the inner wall surface of the ring wall is a reflective surface, for example, formed by coating a metal surface onto the inner wall surface or by polishing the inner wall surface, but it is not limited to this, and the reflective surface can also be formed in other ways.

[0110] Figure 12 In the middle, the upper surface of the ring wall perpendicular to the substrate 1010 surrounding the light source 1011. The first part 1201 of the ring wall surrounding the light source 1011, away from the light sensor 1013. Figure 12 The right side of the light source 1011 is higher than the second part 1203 in the ring wall near the light sensor 1013. Figure 12 The reference light R directed toward the right side wall of the enclosure 1003 is reflected by the first portion 1201 to increase the intensity of the smoke-reflected light S irradiating 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 first portion 1201 is located on the left side of the light source 1011, so that the reference light R directed toward the right side wall of the enclosure 1003 is reflected by the first portion 1201 to increase the intensity of the smoke-reflected light S irradiating the smoke 90. Figure 12There is no specific limitation on the thickness in the left and right directions. The height of the ring wall connecting the first part 1201 and the second part 1203 can be configured to be the same as the height of the second part 1203, or to increase sequentially from the second part 1203 toward the first part 1201, without any specific limitation.

[0111] Figure 13 In the middle, the ring wall surrounding the light source 1011 also includes a first part 1301 that is far away from the light sensor 1013. Figure 12 The right side of the light source 1011 and the second part 1303 near the light sensor 1013 Figure 12 (Left side of the light source 1011). In order to achieve the same Figure 12 With a similar effect, the first part 1301 is tilted toward the light sensor 1013, and its tilt angle is shown as a2. Figure 13 The second part 1303 is also tilted toward the light sensor 1013, and its tilt angle is shown as a1. Figure 13 In this embodiment, the tilt angle α2 may be equal to or different from α1, without specific limitations. For example, α1 and α2 may be greater than 0 degrees and less than 90 degrees, or α1 and α2 may be 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 is not tilted toward the photosensor 1013, while only the first portion 1301 is tilted toward the photosensor 1013. The annular wall connecting the first portion 1301 and the second portion 1303 may be configured to be perpendicular to the upper surface of the substrate 1010 and not tilted, and its inner wall surface may or may not be provided with a reflective surface.

[0112] In addition, although Figure 13 The first portion 1301 and the second portion 1303 are shown to be approximately the same height, but the invention is not limited thereto. In other embodiments, the first portion 1301 is higher than (or longer than) the second portion 1303, similarly. Figure 12 As shown, but with a tilt angle.

[0113] It must be noted that, although the above Figure 12 and Figure 13 The inner wall surface of the ring wall surrounding the display light source 1011 is a reflective surface (or a mirror surface) to increase the intensity of the smoke reflected light S, but the invention is not limited thereto. In other embodiments, the inner wall surface of the ring wall may not be a reflective surface formed by additional treatment.

[0114] Please refer to Figures 14A to 14C The diagram shows a cross-sectional view of smoke detectors 1400, 1400', and 1400" according to a fifth embodiment of the present invention. Smoke detectors 1400, 1400', and 1400" also include 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 since they have already been described above, they will not be repeated here.

[0115] The difference between the fifth embodiment and the fourth embodiment described above is that the fifth embodiment shifts the illumination range of the light source 1011 toward the light sensor 1013 by configuring a light guide element. For the sake of simplicity, [the accompanying drawings are omitted]. Figures 14A to 14C The cover 1003 has been omitted.

[0116] Figure 14A In this light guide element, a lens 1405 and a reflector 1407 are included. The lens 1405 is made of, for example, plastic or glass. The optical axis of the lens 1405 is tilted towards the light sensor 1013 at an angle θ, which is preferably greater than 20 degrees and less than 45 degrees. The reflector 1407 is disposed on the 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 conjunction with the tilt of the lens 1405, a first reflective portion of the reflector 1407 away from the light sensor 1013 ( Figure 14A The right side of the light source 1011 is higher than the second reflective part of the reflector 1407 near the light sensor 1013. Figure 14A (Left side of the light source 1011). Meanwhile, a light guide element is disposed on the upper surface of the substrate 1010 and covers the light source 1011.

[0117] Figure 14B In this embodiment, the light guide element includes a lens 1405' and a reflector 1407'. In this embodiment, a ring wall is disposed on the upper surface of the substrate 1010, surrounding the light source 1011 and the light sensor 1013. As described above, the purpose of the ring wall is to control the illumination range of the light source 1011 and the light-receiving range of the light sensor 1013. Figure 14B In this configuration, the light guide element is positioned on the ring wall surrounding the light source 1011, and the optical axis of the lens 1405' is also tilted at an angle θ toward the light sensor 1013, thus achieving the same effect as... Figure 14A A similar effect is achieved by reducing the light intensity directed towards the right side wall of the enclosure (omitted and not shown) and increasing the light intensity directed towards the light sensor 1013. It must be noted that the shape of the ring wall is not limited to... Figure 14B As shown.

[0118] It must be noted that, although Figure 14B The left side of lens 1405' does not have a reflector 1407', but the present invention is not limited thereto. If the thickness of lens 1405' is large or the tilt angle θ is small, a reflector 1407' can still be arranged on the left side of lens 1405', similar to... Figure 14A .

[0119] also, Figure 14A The implementation method can be compared with Figure 12 Combined, for example, shown in Figure 14C . Figure 14CIn this embodiment, the smoke detector 1400 includes a light guide element disposed on the upper surface of the substrate 1010 and located within the annular wall. In this embodiment, the side edge of the lens 1405 may not have a reflector; instead, a reflective surface may be disposed on the inner wall surface of the annular wall surrounding the light source 1011. Similarly... Figure 12 The first part 1401 in the ring wall, away from the light sensor 1013 Figure 14C The right side of the light source 1011 is higher than the second part 1403 in the ring wall near the light sensor 1013. Figure 14C (Left side of the central light source 1011). Additionally... Figure 14C Further cooperation is also possible Figure 13 The implementation method combines the two, that is, the first part 1401 of the ring wall is tilted toward the light sensor 1013. As for the second part 1403 of the ring wall, as described in the fourth embodiment above, it can be kept perpendicular to the upper surface of the substrate 1010 or tilted toward the light sensor 1013.

[0120] Please refer to Figures 15A to 15B The image shown is a cross-sectional view of smoke detectors 1500 and 1500' according to the sixth embodiment of the present invention. Smoke detectors 1500 and 1500' also include a substrate 1010, a light source 1011, and a light sensor 1013, which have already been described above and will not be repeated here.

[0121] The sixth embodiment involves further disposing of a secondary substrate 1507 on the upper surface of the substrate 1010. The secondary substrate 1507 is electrically connected to the substrate 1010 and its first surface (i.e., the upper surface) is tilted towards the light sensor 1013 at an angle θ, which is preferably greater than 20 degrees and less than 45 degrees.

[0122] It must be noted that, although Figure 15A The cross-section of the secondary substrate 1507 is triangular, but the present invention is not limited thereto. The cross-section of the secondary substrate 1507 can be other shapes, as long as its upper surface is inclined toward the photosensor 1013.

[0123] The secondary substrate 1507 can be a printed circuit board or a flexible substrate, without any specific restrictions, as long as the light source 1011 can be coupled to the substrate 1010.

[0124] like Figure 15A As shown, by placing the light source 1011 on the first surface of the sub-substrate 1507, the same effect as the fourth and fifth embodiments described above can be achieved.

[0125] also, Figure 15A The implementation method can be compared with Figure 12 The implementation methods are combined, such as Figure 15B As shown. Figure 15BIn the smoke detector 1500', a ring wall is disposed on the upper surface of the substrate 1010 and surrounds the sub-substrate 1507 and the light source 1011. The purpose of the ring wall has been explained above. The first portion 1501 of the ring wall surrounding the light source 1011 is located away from the light sensor 1013. Figure 15B The right side of the intermediate substrate 1507 is higher than the second part 1503 in the ring wall near the light sensor 1013. Figure 15B (Left side of the intermediate substrate 1507), and at least the inner wall surface of the first part 1501 is a reflective surface.

[0126] also, Figure 15A The implementation method can also be combined with Figure 14A The implementation method is combined as follows. That is, the smoke detector 1500' also includes a lens 1505 covering the light source 1011, and the optical axis of the lens 1505 is tilted towards the light sensor 1013 at an angle θ2, which is preferably greater than 10 degrees and less than 20 degrees. Meanwhile, the tilt angle θ1 of the first surface of the secondary substrate 1507 is less than... Figure 15A The tilt angle θ, for example, greater than 10 degrees and less than 15 degrees. In other words, Figure 15B In this process, the tilt angle θ1 of the sub-substrate 1507 and the tilt angle θ2 of the lens 1505 are simultaneously utilized to achieve... Figure 15A The effect of tilt angle θ of the sub-substrate 1507.

[0127] In summary, the smoke detectors of the fourth to sixth embodiments described above can be combined and configured, and are not limited to specific configurations. Figure 14C and Figure 15B As shown.

[0128] In summary, known smoke detectors, due to their reliance on a single threshold, are unsuitable for diverse environments. For example, the amount of interfering objects differs between indoor and outdoor environments, and different types of smoke generate different detection signals, leading to a high false alarm rate. Therefore, this invention provides a smoke detector with a low false alarm rate (see reference). Figure 1B , Figures 3 to 4 and Figures 5A to 5B (etc.), which can adjust multiple condition thresholds used relative to different specifications or current detection results, effectively reducing the false alarm rate. In addition, the smoke detector of the present invention is structurally provided with a light guide structure, including a ring wall, a lens and / or a sub-substrate, to shift the illumination range of the light source toward the direction of the light sensor, so as to further reduce the false alarm rate.

[0129] While the present invention has been disclosed through the foregoing examples, it is not intended to limit the invention. Anyone skilled in the art to which this invention pertains can make various modifications and alterations without departing from the spirit and scope of the invention. Therefore, the scope of protection of this invention shall be determined by the appended claims.

Claims

1. A smoke detector comprising: substrate; A light source disposed on the upper surface of the substrate; A light sensor disposed on the upper surface of the substrate; as well as A ring wall, disposed on the upper surface of the substrate and surrounding the light source, is used to offset the illumination range of the light source toward the photosensor. Wherein, the first portion of the ring wall farther from the light sensor is higher than the second portion of the ring wall closer to the light sensor, and The inner wall surface of the ring wall is a reflective surface to increase the intensity of scattered light, which is the difference between the current detection signal and the reference detection signal.

2. The smoke detector according to claim 1, wherein, The ring wall is perpendicular to the upper surface.

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

4. The smoke detector according to claim 1, wherein, The first portion of the ring wall that is away from the light sensor is tilted toward the light sensor.

5. The smoke detector according to claim 4, wherein, The second portion of the ring wall near the light sensor is perpendicular to the upper surface.

6. The smoke detector according to claim 4, wherein, The second portion of the ring wall near the light sensor is tilted toward the light sensor.

7. The smoke detector according to claim 6, wherein, The first part and the second part have the same tilt angle.

8. The smoke detector according to claim 6, wherein, The tilt angles of the first part and the second part are different.

9. The smoke detector according to claim 6, wherein, The first part is higher than the second part.

10. A smoke detector comprising: substrate; A light source disposed on the upper surface of the substrate; A light sensor disposed on the upper surface of the substrate; and A light guide element for shifting the illumination range of the light source toward the light sensor, and comprising: A lens, the optical axis of which is tilted toward the light sensor; and A reflector is disposed on the side edge of the lens, and a first reflective portion of the reflector that is far from the light sensor is higher than a second reflective portion of the reflector that is close to the light sensor to increase the intensity of scattered light, which is the difference between the current detection signal and the reference detection signal.

11. The smoke detector according to claim 10, wherein, The tilt angle of the optical axis of the lens is greater than 20 degrees and less than 45 degrees.

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

13. 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 disposed on the ring wall.

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 disposed on the upper surface of the substrate and located within the annular wall. The inner wall surface of the ring wall is a reflective surface, and The first portion of the ring wall that is farther away from the light sensor is higher than the second portion of the ring wall that is closer to the light sensor.

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 disposed on the upper surface of the substrate and located within the annular wall. The inner wall surface of the ring wall is a reflective surface, and The first portion of the ring wall that is away from the light sensor is tilted toward the light sensor.

16. A smoke detector comprising: substrate; A light sensor disposed on the upper surface of the substrate; A secondary substrate is disposed on the upper surface of the substrate and electrically connected to the substrate, wherein the first surface of the secondary substrate is inclined toward the photosensitive sensor; as well as A light source disposed on the first surface of the secondary substrate; as well as A ring wall, disposed on the upper surface of the substrate and surrounding the sub-substrate. Wherein, the first portion of the ring wall farther from the light sensor is higher than the second portion of the ring wall closer to the light sensor, and The inner wall surface of the ring wall is a reflective surface to increase the intensity of scattered light, which is the difference between the current detection signal and the reference detection signal.

17. The smoke detector according to claim 16, wherein, The tilt angle of the first surface of the sub-substrate is greater than 20 degrees and less than 45 degrees.

18. The smoke detector of claim 16, further comprising: A lens, the optical axis of which is tilted toward the light sensor, wherein, The tilt angle of the first surface of the secondary substrate is greater than 10 degrees and less than 15 degrees, and The tilt angle of the optical axis of the lens is greater than 10 degrees and less than 20 degrees.

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