Dust sensor for eliminating stray light by using light receiving element
By adopting a series or anti-parallel light receiving element structure in the dust sensor, combined with an amplifier circuit and a single-chip microcomputer controller, the problems of stray light detection accuracy and stability of the dust sensor are solved, and the stray light is electrically eliminated and the effective working range of the amplifier circuit is expanded.
Patent Information
- Application Number
- CN202510918113.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-03
- Publication Date
- 2025-09-12
AI Technical Summary
When existing dust sensors detect the concentration of particulate matter in the air, stray light has an adverse effect on their performance, resulting in reduced detection sensitivity and increased noise, and existing measures are difficult to completely eliminate stray light.
A dust sensor containing first and second light receiving elements is used, which are connected in series or in reverse parallel. The second light receiving element is used to subtract the signal component from the stray light. The stray light is electrically eliminated by combining an amplifying circuit and a single-chip controller.
Effectively eliminate the influence of stray light on detection precision and accuracy, expand the working range of the amplification circuit, and improve the stability and detection effect of the sensor.
Smart Images
Figure CN120629073A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a dust sensor, in particular to a dust sensor which utilizes a light receiving element to eliminate stray light. Background Art
[0002] Dust sensors detect dust by illuminating the detection area through which dust or smoke (hereinafter referred to as "dust") passes and detecting the scattered light caused by the dust. When dust sensors detect the concentration of particulate matter in the air, stray light (non-target light sources or unexpected light signals, including ambient light sources, internal optical reflections, and non-monochromatic light sources) will have multiple adverse effects on their performance.
[0003] Stray light, acting as background noise, can drown out weak target signals (such as scattered light from low dust concentrations), reducing the sensor's ability to detect fine particles. When the stray light intensity is comparable to the target signal, the linear relationship between the sensor output and particle concentration is disrupted, resulting in reduced dust sensor sensitivity and increased noise. Long-term stray light interference can cause "light saturation" in photodetectors, increasing output signal volatility or uncertainty.
[0004] Therefore, to improve the detection precision, accuracy, and stability of dust sensors, it's necessary to eliminate the adverse effects of stray light on dust detection. Shielding the detection area from external light—using optical structures to block light—is one common and effective measure. Other approaches include adding filters to light-emitting elements or using laser diodes instead of conventional diodes to reduce the spectral width. These measures are merely attempts to reduce stray light, but they cannot completely eliminate it. Summary of the Invention
[0005] In view of the shortcomings of the existing technology, the present invention proposes a dust sensor that uses a light receiving element to eliminate stray light, taking a different approach and aiming to eliminate the signal generated by the influence of stray light by using electrical and physical methods.
[0006] A dust sensor containing a light receiving element for eliminating stray light comprises a light emitting element, a light receiving element, an amplifier circuit for amplifying a photocurrent signal generated in a general light receiving element, and a single-chip microcomputer controller. The single-chip microcomputer controller is provided with an I / O control interface connected to a driving circuit of the light emitting element. The amplifier circuit outputs a signal connected to the single-chip microcomputer controller. The light receiving element comprises a first light receiving element for receiving light and a second light receiving element for subtracting a signal component from unnecessary stray light. The second light receiving element is connected in series or in reverse parallel with the first light receiving element. The two ends of the first light receiving element are respectively connected to the differential signal input ends of a first-stage amplifier of the amplifier circuit.
[0007] This dust sensor detects dust by illuminating a detection area where dust or smoke (hereinafter referred to as "dust") passes and detecting the scattered light caused by the dust. The photocurrent signal generated by the first light-receiving element receiving the light is amplified, and the second light-receiving element is used to subtract the stray light signal component from the unwanted stray light. By providing a second light-receiving element to subtract the signal component caused by unwanted stray light, the signal component can be accurately subtracted with a waveform that is substantially identical to that of the first light-receiving element, objectively expanding the operating range of the amplifier circuit and preventing any shortfalls in the operating range.
[0008] In the dust sensor, the first light receiving element and the second light receiving element are connected in series, wherein the cathode of the first light receiving element is connected to the anode of the second light receiving element, and the cathode of the second light receiving element is connected to the power supply terminal.
[0009] In the dust sensor, the first light receiving element and the second light receiving element are connected in series, wherein the anode of the first light receiving element is connected to the cathode of the second light receiving element, and the anode of the second light receiving element is connected to the power supply terminal.
[0010] In the dust sensor, a first light receiving element and a second light receiving element are connected in anti-parallel, with the cathode of the first light receiving element connected to the anode of the second light receiving element, and the anode of the first light receiving element connected to the cathode of the second light receiving element. By connecting the two light receiving elements in anti-parallel, a bias voltage for the second light receiving element is not required, and no additional bias voltage is required.
[0011] The dust sensor, the first light receiving element and the second light receiving element are arranged in the detection area: the second light receiving element is arranged near the first light receiving element, receives approximately the same amount of stray light, and is arranged so that the scattered light of dust hitting the first light receiving element is greater than the scattered light of dust hitting the second light receiving element, thereby offsetting the influence of stray light.
[0012] 1. The dust sensor of the present invention utilizes a light receiving element to eliminate stray light. By providing a second light receiving element for subtracting the signal component caused by unnecessary stray light, the signal component can be accurately subtracted using a waveform substantially identical to that of the first light receiving element. Therefore, the influence of stray light on the detection precision and accuracy of the dust sensor can be effectively eliminated. At the same time, the dust sensor objectively has the effect of expanding the operating range of the amplifier circuit and suppressing the insufficient operating range of the amplifier circuit.
[0013] 2. In the dust sensor of the present invention, the cathode of the first light receiving element is connected to the anode of the second light receiving element, or the anode of the first light receiving element is connected to the cathode of the second light receiving element. By connecting the anode and cathode of each of the first and second light receiving elements, light receiving current can be easily subtracted.
[0014] 3. In the dust sensor of the present invention, the cathode of the first light receiving element is connected to the anode of the second light receiving element, and the anode of the first light receiving element is connected to the cathode of the second light receiving element. By connecting the two light receiving elements in antiparallel, a bias voltage for the second light receiving element is not required, and no additional bias voltage is required.
[0015] 4. The dust sensor of the present invention has a first light-receiving element and a second light-receiving element arranged so that the second light-receiving element is positioned adjacent to the first light-receiving element and is arranged so that light scattered by dust impinging on the first light-receiving element is greater than light scattered by dust impinging on the second light-receiving element. By positioning the first and second light-receiving elements adjacent to each other, they receive approximately the same amount of stray light, thereby canceling out stray light. Furthermore, this arrangement, which creates a structural difference in the amount of incident dust-scattered light, enables detection of stray light without deducting dust-scattered light. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Figure 1 FIG2 is a schematic structural diagram of a dust sensor embodiment 1 of the present invention; Figure 2 FIG2 is a schematic structural diagram of a dust sensor embodiment 2 of the present invention; Figure 3 FIG2 is a schematic structural diagram of a dust sensor embodiment 3 of the present invention; Figure 4 The figure shows a schematic diagram of the configuration structure of the light receiving element of the dust sensor of the present invention; Figure 5 Shown is a signal timing diagram of the dust sensor of the present invention and the principle of subtracting stray light components. DETAILED DESCRIPTION
[0017] In order to make the technical concept and advantages of the invention more clearly understood, the technical solution of the present invention is further described in detail below with reference to the accompanying drawings. It should be understood that the following embodiments are only used to explain and illustrate the preferred embodiments of the present invention and should not be regarded as and do not constitute a limitation on the scope of patent protection claimed by the present invention.
[0018] like Figure 1-Figure 3As shown, the present invention proposes a dust sensor containing a light receiving element for eliminating stray light, including a light emitting element, a light receiving element, an amplifier circuit for amplifying a photocurrent signal generated in a general light receiving element, and a single-chip microcomputer controller. The single-chip microcomputer controller is provided with an I / O control interface connected to the driving circuit of the light emitting element, and the output signal of the amplifier circuit is connected to the single-chip microcomputer controller. The light receiving element includes a first light receiving element for receiving light and a second light receiving element for subtracting a signal component from unnecessary stray light. The second light receiving element is connected in series or in reverse parallel with the first light receiving element; wherein the two ends of the first light receiving element are respectively connected to the differential signal input end of the first-stage amplifier of the amplifier circuit.
[0019] This dust sensor detects dust by illuminating a detection area through which dust or smoke (hereinafter referred to as "dust") passes with light and detecting scattered light caused by the dust. The photocurrent signal generated in the first light receiving element that receives the light is amplified, and the second light receiving element is used to subtract the stray light signal component from the unnecessary stray light.
[0020] By setting up a second light receiving element for subtracting the signal component caused by unnecessary stray light, the signal component can be accurately subtracted with a waveform roughly the same as the waveform of the first light receiving element, thereby having the effect of expanding the operating range of the amplifier circuit and suppressing the insufficient operating range of the amplifier circuit. Example
[0021] See also Figure 1 In the dust sensor of this embodiment, the first light receiving element and the second light receiving element are connected in series, wherein the cathode of the first light receiving element is connected to the anode of the second light receiving element, and the cathode of the second light receiving element is connected to the power supply terminal. Example
[0022] See also Figure 2 In the dust sensor of this embodiment, a light receiving element and a second light receiving element are connected in series, wherein the anode of the first light receiving element is connected to the cathode of the second light receiving element, and the anode of the second light receiving element is connected to the power supply terminal.
[0023] In the foregoing two embodiments, the light receiving current can be subtracted relatively easily by connecting the anode and cathode of each of the first and second light receiving elements. Example
[0024] See also Figure 3 In the dust sensor of this embodiment, the first light receiving element and the second light receiving element are connected in reverse parallel, wherein the cathode of the first light receiving element is connected to the anode of the second light receiving element, and the anode of the first light receiving element is connected to the cathode of the second light receiving element.
[0025] By connecting the two light receiving elements in anti-parallel, a bias voltage for the second light receiving element is unnecessary, and an additional bias voltage is not required.
[0026] Figure 4 The figure shows a schematic diagram of the configuration of the light receiving elements of the dust sensor of the present invention; the arrangement of the first light receiving element and the second light receiving element in the detection area: the second light receiving element is arranged near the first light receiving element, and is arranged so that the scattered light of the dust incident on the first light receiving element is greater than the scattered light of the dust incident on the second light receiving element.
[0027] By placing the first and second light-receiving elements near each other, receiving approximately the same amount of stray light, and arranging them so that the scattered light from dust impinging on the first light-receiving element is greater than the scattered light from dust impinging on the second light-receiving element, the second light-receiving element, which is used to subtract the signal component caused by unwanted stray light, can accurately subtract the signal component with a waveform approximately identical to that of the first light-receiving element. This effectively eliminates the impact of stray light on the dust sensor's detection precision and accuracy. Furthermore, by creating a structural difference in the amount of incident dust-scattered light, stray light can be detected without subtracting it. This also objectively expands the operating range of the amplifier circuit and mitigates any shortfalls in the operating range.
[0028] like Figure 5 As shown in FIG, the signal timing diagram of the dust sensor of the present invention illustrates that the present invention can effectively eliminate the influence of the stray light component on the measurement result of the dust sensor, thereby improving the accuracy and stability of the detection result.
Claims
1. A dust sensor that eliminates stray light using a light-receiving element, comprising a light-emitting element, a light-receiving element, an amplifier circuit for amplifying the photocurrent signal generated by the light-receiving element, and a single-chip microcomputer controller. The single-chip microcomputer controller includes an I / O control interface connected to a drive circuit for the light-emitting element, and the amplifier circuit outputs a signal that is connected to the single-chip microcomputer controller. The sensor is characterized by: The light receiving element includes a first light receiving element for receiving light and detecting dust passing through the detection area; The light receiving element includes a second light receiving element that receives light and is used to subtract a stray light signal component from unnecessary stray light.
2. The dust sensor according to claim 1, wherein: The second light receiving element is connected in series with the first light receiving element; wherein both ends of the first light receiving element are respectively connected to the differential signal input ends of the first stage amplifier of the amplifying circuit.
3. The dust sensor according to claim 2, characterized in that: The first light receiving element and the second light receiving element are connected in series, wherein the cathode of the first light receiving element is connected to the anode of the second light receiving element, and the cathode of the second light receiving element is connected to the power supply terminal.
4. The dust sensor according to claim 2, wherein: The first light receiving element and the second light receiving element are connected in series, wherein the anode of the first light receiving element is connected to the cathode of the second light receiving element, and the anode of the second light receiving element is connected to the power supply terminal.
5. The dust sensor according to claim 2, 3 or 4, characterized in that: The first light receiving element and the second light receiving element are arranged in the detection area: the second light receiving element is arranged near the first light receiving element and is arranged so that the scattered light of dust incident on the first light receiving element is larger than the scattered light of dust incident on the second light receiving element.
6. The dust sensor according to claim 1, wherein: The second light receiving element is connected in reverse parallel to the first light receiving element; wherein two ends of the first light receiving element are respectively connected to the differential signal input ends of the first stage amplifier of the amplification circuit.
7. The dust sensor according to claim 6, characterized in that: The first and second light receiving elements are connected in antiparallel, with the cathode of the first light receiving element connected to the anode of the second light receiving element and the anode of the first light receiving element connected to the cathode of the second light receiving element.
8. The dust sensor according to claim 1, 6 or 7, characterized in that: The first light receiving element and the second light receiving element are arranged in the detection area: the second light receiving element is arranged near the first light receiving element and is arranged so that the scattered light of dust incident on the first light receiving element is larger than the scattered light of dust incident on the second light receiving element.