A pyroelectric sensor with ambient light detection function

Abstract

A pyroelectric sensor with an ambient light detection function comprises a tube cap and a substrate. The tube cap is provided with a first window and an infrared filter is installed on the window. The tube cap is packaged and fixed on a tube base and a cavity is formed between the tube base. The substrate is arranged on the tube base and located in the cavity. A field effect tube and a pyroelectric sensitive element are both arranged in the cavity. The field effect tube is installed on the substrate. The pyroelectric sensitive element is installed above the field effect tube. A plurality of pins are installed below the tube base. The drain and source of the field effect tube are respectively connected to the corresponding pins. The two ends of the pyroelectric sensitive element are respectively connected to the gate of the field effect tube and the pin ground. A second window is provided on the tube cap and an ambient light filter is installed on the window. A photosensitive element is installed in the cavity. An optical path is provided between the photosensitive element and the ambient light filter. An isolation cover is provided on the outer cover of the optical path. The photosensitive element is connected to the corresponding pin or to a photosensitive element matching circuit. The photosensitive element matching circuit is further connected to the corresponding pin.

Description

Technical Field

[0001] The invention belongs to the technical field of sensors, and in particular relates to a pyroelectric sensor with an ambient light detection function. Background Art

[0002] With the development of smart home technology, pyroelectric sensors and ambient light sensors are often used together. Pyroelectric sensors are used to detect human movement, and ambient light sensors are used to detect the intensity of ambient light. The two are combined to determine whether there are people in the environment and the intensity of ambient light.

[0003] A conventional pyroelectric sensor generally comprises a field effect tube 1', a sensitive element 2', a tube cap 3', a tube base 4', an infrared filter 5', and a substrate 6'. The tube cap 3' has a window and an infrared filter 5 is mounted on the window. The structure is as follows: Figure 1 shown.

[0004] An ambient light sensor refers to a sensor such as a photoresistor, a photodiode, a phototransistor or a photosensitive integrated sensor that can detect the intensity of ambient light.

[0005] A common application scenario is smart lighting, and its control block diagram is as follows Figure 2 As shown, it includes a pyroelectric sensor, an ambient light sensor, a control unit, and an execution unit. The pyroelectric sensor is used to detect whether there is a person and output a signal to the control unit; the ambient light sensor detects the light intensity of the working surface and outputs a signal to the control unit. The control unit controls the execution unit whether to turn on the lamp or adjust the luminous intensity of the lamp according to the algorithm.

[0006] Figure 2 In the present invention, pyroelectric sensors and ambient light sensors are two independent products, which need to be packaged and applied separately. The production and application are relatively complicated and the cost is also high. Summary of the invention

[0007] In order to solve the above problems existing in the prior art, the present invention provides a pyroelectric sensor with an ambient light detection function, which improves product reliability, simplifies product structure, is easy to produce and apply, and has low cost.

[0008] The technical solution adopted by the present invention is:

[0009] A pyroelectric sensor with an ambient light detection function comprises a photosensitive element, a photosensitive element matching circuit, an ambient light filter, a field effect tube, a pyroelectric sensitive element, a tube cap, a tube seat, an infrared filter, and a substrate. The tube cap is provided with a first window and an infrared filter is installed on the window. The tube cap is packaged and fixed on the tube seat to form a cavity between the tube seat and the tube seat. The substrate is arranged on the tube seat and located in the cavity. The field effect tube and the pyroelectric sensitive element are both arranged in the cavity. The field effect tube is installed on the substrate. The pyroelectric sensitive element is installed above the field effect tube. A plurality of pins are installed under the tube seat, the drain and source of the field effect tube are connected to the corresponding pins respectively, and the two ends of the pyroelectric sensitive element are connected to the gate and pin of the field effect tube respectively. The feature is that: a second window is opened on the tube cap and an ambient light filter is installed on the window, a photosensitive element is installed in the cavity, an optical path is provided between the photosensitive element and the ambient light filter, an isolation cover is provided on the optical path cover, the photosensitive element is connected to the corresponding pin, or connected to the photosensitive element matching circuit, and the photosensitive element matching circuit is connected to the corresponding pin. The present invention is to seal the pyroelectric sensitive element and the photosensitive element in a packaging cavity, and the two sensitive elements have different detection objects. The pyroelectric sensitive element detects the infrared signal radiated by the human body, with a wavelength of 5-10um, which uses the thermal effect of light; the photosensitive element detects the visible light in the environment, with a wavelength of 0.3-0.8um, which uses the quantum effect of light. And an independent optical path is formed for the two sensitive elements through the isolation cover to ensure the accuracy of detection and avoid the influence of interference light.

[0010] Furthermore, the isolation cover includes an upper light-blocking column and a lower light-blocking column, the photosensitive element is mounted on the substrate, the lower light-blocking column cover is arranged outside the photosensitive element, the upper light-blocking column is mounted between the lower light-blocking column and the upper surface of the tube cap, and a light-guiding column is mounted inside the upper light-blocking column. In the present invention, external light is introduced to the surface of the photosensitive element through the ambient light filter, the light-guiding column, the lower light-blocking column and the upper light-blocking column, and the light-guiding column fully emits the external light, so that the external light is confined in the lower light-blocking column and the upper light-blocking column, and is completely isolated from the infrared signal incident from the first window.

[0011] Furthermore, the upper light blocking column and the lower light blocking column are concentrically arranged and connected to form an integrated structure.

[0012] Alternatively, the isolation cover is a packaging cavity, the photosensitive element is installed in the packaging cavity, the packaging cavity is installed on the tube cap, the upper surface of which exposes the second window or is flush with the second window, and the ambient light filter is installed on the upper surface of the packaging cavity. In the present invention, the external light directly reaches the surface of the photosensitive element through the ambient light filter, the external light is confined in the packaging cavity, and is completely isolated from the infrared signal incident from the first window.

[0013] Furthermore, the packaging cavity is made of a material that is opaque to visible light.

[0014] Furthermore, the packaging cavity is installed on the substrate through a column and is connected to the tube cap.

[0015] Furthermore, the photosensitive element is a photoresistor, a photodiode, a phototransistor or a photosensitive integrated sensor.

[0016] Furthermore, an impedance matching resistor is connected in parallel to the pyroelectric sensitive element.

[0017] The beneficial effects of the present invention are: it has two windows for infrared radiation detection and ambient light detection, and at the same time, the pyroelectric sensitive element and the photoelectric sensitive element are sealed in the same packaging structure, and signal isolation is effectively realized to ensure detection accuracy. It can simultaneously detect the infrared signal of the human body and the intensity of ambient light, and can be directly connected to the control unit. It has the characteristics of simplified product structure, convenient production and application, low cost, high reliability, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is the structure diagram of the traditional pyroelectric infrared sensor;

[0019] Figure 2 This is the control block diagram of the existing intelligent lighting fixtures;

[0020] Figure 3 It is the integrated control block diagram of pyroelectric infrared sensor and ambient light sensor;

[0021] Figure 4 It is a structural schematic diagram of a first embodiment of the present invention;

[0022] Figure 5 It is a structural schematic diagram of a second embodiment of the present invention;

[0023] Figure 6 This is a schematic diagram of the installation of the first embodiment of the present invention;

[0024] Figure 7 This is a schematic diagram of the installation of the second embodiment of the present invention;

[0025] Figure 8 It is the equivalent circuit diagram of the present invention.

[0026] In the figure: 1-field effect transistor; 2-sensitive element; 3-tube cap; 4-tube socket; 5-infrared filter; 6-substrate; 7-ambient light filter; 8-photosensitive element; 9-internal lead; 10-lower light blocking column; 11-light guiding column; 12-upper light blocking column; 13-packaging cavity; 14-photosensitive element output pin; 15-impedance matching resistor; 16-pin ground; 17-source pin; 18-drain pin; 19-tube socket for sealing the component. DETAILED DESCRIPTION

[0027] The present invention is further described below in conjunction with specific embodiments, but the present invention is not limited to these specific embodiments. Those skilled in the art should recognize that the present invention covers all possible alternatives, improvements and equivalents within the scope of the claims.

[0028] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "clockwise", "counterclockwise" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, the meaning of "multiple" is two or more, unless otherwise clearly defined.

[0029] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0030] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0031] Embodiment 1

[0032] See also Figure 4 , Figure 8The present embodiment provides a pyroelectric sensor with an ambient light detection function, comprising a field effect tube 1, a pyroelectric sensitive element 2, a tube cap 3, a tube base 4, an infrared filter 5, and a substrate 6. The tube cap 3 is provided with a first window and an infrared filter 5 is installed on the window. The tube cap 3 is packaged and fixed on the tube base 4 to form a cavity between the tube base 4. The substrate 6 is arranged on the tube base 4 and located in the cavity. The field effect tube 1 and the pyroelectric sensitive element 2 are both arranged in the cavity. The field effect tube 1 is installed on the substrate 6. The pyroelectric sensitive element 2 is installed above the field effect tube 1. A drain pin 18, a source pin 17, and a pin ground 1 are installed below the tube base 4. 6. A photosensitive element output pin 14. The drain and source of the field effect tube 1 are connected to the corresponding drain pin 18 and source pin 17 respectively. The two ends of the pyroelectric sensitive element 2 are connected to the gate of the field effect tube 1 and the pin ground 16 respectively. The pyroelectric sensitive element 2 is connected in parallel with an impedance matching resistor 15. A second window is provided on the cap 3 and an ambient light filter 7 is installed on the window. A photosensitive element 8 is installed in the cavity. An optical path is provided between the photosensitive element 8 and the ambient light filter 7. An isolation cover is provided on the optical path cover. The two ends of the photosensitive element 8 are connected to the pin ground 16 of the pyroelectric sensitive element 2 and the photosensitive element output pin 14 respectively. The present invention seals the pyroelectric sensitive element 2 and the photosensitive element 8 in a packaging cavity. The two sensitive elements detect different objects. The pyroelectric sensitive element detects infrared signals radiated by the human body with a wavelength of 5-10um, which uses the thermal effect of light; the photosensitive element detects visible light in the environment with a wavelength of 0.3-0.8um, which uses the quantum effect of light. An independent light path is formed for the two sensitive elements through an isolation cover to ensure the accuracy of detection and avoid the influence of interference light.

[0033] The isolation cover of this embodiment includes an upper light-blocking column 12 and a lower light-blocking column 10, the photosensitive element 8 is mounted on the substrate 6, the lower light-blocking column 10 is covered outside the photosensitive element 8, the upper light-blocking column 12 is mounted between the lower light-blocking column 10 and the upper surface of the tube cap 3, the upper light-blocking column 12 and the lower light-blocking column 10 are concentrically arranged and connected into an integral structure, and a light-guiding column 11 is installed in the upper light-blocking column 12. The external light of the present invention is introduced into the surface of the photosensitive element 8 through the ambient light filter 7, the light-guiding column 11, the lower light-blocking column 10 and the upper light-blocking column 12, and the light-guiding column 11 fully emits the external light, so that the external light is confined in the lower light-blocking column 10 and the upper light-blocking column 12, and is completely isolated from the infrared signal incident from the first window.

[0034] The photosensitive element 8 described in this embodiment is a photoresistor, a photodiode, a phototransistor or a photosensitive integrated sensor, and can also be a product that has been packaged. The installation and wiring methods can be adjusted accordingly according to different product forms. The photosensitive element 8 can be connected to the corresponding pin, or it can be connected to the photosensitive element matching circuit, and the photosensitive element matching circuit is connected to the corresponding pin. The photosensitive element matching circuit is a processing circuit adapted to the photosensitive element, which realizes functions such as signal conversion and amplification. Taking the photosensitive diode as an example, its matching circuit is an integrated circuit including an IV amplifier circuit and a voltage amplifier circuit. The photosensitive diode is connected to the input end of the integrated circuit, and the output of the integrated circuit is connected to the corresponding pin. The current signal generated by the photosensitive diode is converted into a voltage signal by the IV amplifier circuit, and then amplified to a certain amplitude by the voltage amplifier circuit for output.

[0035] The filtering characteristics of the ambient light filter 7 described in this embodiment are different according to different application scenarios and different photosensitive elements. The ambient light filter 7 can be a human eye curve spectrum characteristic, a bandpass filter characteristic, or a full-band pass characteristic based on the spectral characteristics of the internal photosensitive element. The processing circuit connected to the back end of the pyroelectric sensitive element 2 can be an analog output type composed of JFET, or a digital output type composed of a digital processing chip. The installation and connection methods can be adjusted accordingly according to different product forms.

[0036] See also Figure 3 , a pyroelectric sensor with an ambient light detection function described in the present invention can be directly connected to a control unit. The intelligent lamp using the present invention includes a pyroelectric sensor with an ambient light detection function, a control unit, and an execution unit. The pyroelectric sensor with an ambient light detection function simultaneously outputs a human body detection signal and an ambient light detection signal to the control unit. The control unit controls the execution unit whether to turn on the lamp or adjust the luminous intensity of the lamp based on an algorithm. The intelligent lamp can detect human infrared signals and ambient light signals at the same time. When detecting the human body, the infrared radiation radiated by the human body is concentrated on the pyroelectric sensitive element 2. The sensitive element will receive the temperature change of the infrared radiation of the human body, lose the charge balance, release the charge outward, and generate a signal. The central wavelength of the infrared radiation radiated by the human body is 9 to 10um, and the wavelength sensitivity detected by the sensitive element is 0.2 to 20um. In order to have a higher sensitivity to infrared radiation in the wavelength range of the human body, a window equipped with an infrared filter is opened. This infrared filter allows infrared radiation in the wavelength range of 9-10um radiated by the human body to pass through and blocks other wavelengths. When detecting external ambient light, the incident light irradiates the photosensitive element 8, and the photosensitive element 8 generates a current signal.

[0037] See also Figure 6 The steps for installing a pyroelectric sensor with an ambient light detection function described in this embodiment are as follows:

[0038] Step 1: Install the infrared filter 5 and the ambient light filter 7 on the corresponding windows of the tube cap 3 respectively, and install the light blocking column 12 and the light guiding column 11 directly below the ambient light filter 7.

[0039] Step 2: Install the lower light blocking column 10 onto the surface of the tube holder 19 of the pre-sealed component, so that the lower light blocking column 10 covers the photosensitive component 8.

[0040] Step 3: Match the structures assembled in step 1 and step 2, so that the upper light blocking column 12 and the lower light blocking column 10 are concentric, and cap the structures after matching to complete the packaging of the entire product. The product packaged in this structure can block the signal interference between the two windows.

[0041] The photosensitive element 8 is a photosensitive sensor, which is a complete sensor including a photoelectric sensor and its supporting circuits that can be used to detect the intensity of ambient light. In this embodiment, it is a phototransistor. The ambient light filter 7 is a visible light bandpass filter.

[0042] The pyroelectric sensor with ambient light detection function of the present invention integrates the structure of the pyroelectric infrared sensor and the photoelectric sensor, and realizes the independence of the optical paths of the pyroelectric detection signal and the ambient light detection signal, so that there is no interference between the signals. Compared with the traditional pyroelectric infrared sensor, the pyroelectric sensor with ambient light detection function of the present invention can save an independent photoelectric sensor component, save the consumption of packaging resources, reduce the number of pins, improve the plug-in efficiency, reduce the number of solder joints, and reduce the production cost.

[0043] Embodiment 2

[0044] See also Figure 5 The difference between this embodiment and the first embodiment is that the isolation cover is a packaging cavity 13, the packaging cavity 13 is made of metal materials such as stainless steel, PVC doped with titanium dioxide and other non-transparent visible light materials, the photosensitive element 8 is installed in the packaging cavity 13 and connected to the corresponding external pins through the internal lead 9, the packaging cavity 13 is installed on the cap 3, the packaging cavity 13 is installed on the substrate 6 through the column and connected to the cap 3, and the upper surface thereof exposes the second window or is flush with the second window, and the ambient light filter 7 is installed on the upper surface of the packaging cavity 13. The external light of the present invention directly reaches the surface of the photosensitive element 8 through the ambient light filter 7, the external light is confined in the packaging cavity 13, and is completely isolated from the infrared signal incident from the first window.

[0045] See also Figure 7 The steps for installing a pyroelectric sensor with an ambient light detection function described in this embodiment are as follows:

[0046] Step 1: Install the photosensitive element 8 into the packaging cavity 13 of the tube cap 3 .

[0047] Step 2: Match the structure assembled in step 1 with the tube seat 19 of the pre-sealed components and cap them.

[0048] Step 3: Install the ambient light filter 7 onto the photoelectric sensor window of the tube cap 13. The product packaged in this structure can block the signal interference between the two windows.

[0049] The remaining structures and functions can refer to those described in the first embodiment.

[0050] It should be noted that the above embodiments can be freely combined as needed. The above description is only a detailed description of the preferred embodiments and principles of the present invention. For ordinary technicians in this field, according to the ideas provided by the present invention, there will be changes in the specific implementation methods, and these changes should also be regarded as the protection scope of the present invention.

Claims

1. A pyroelectric sensor with ambient light detection function, comprising a photosensitive element, a photosensitive element matching circuit, an ambient light filter, a field effect tube, a pyroelectric sensitive element, a tube cap, a tube seat, an infrared filter, and a substrate, wherein the tube cap is provided with a first window and an infrared filter is installed on the window, the tube cap is packaged and fixed on the tube seat and a cavity is formed between the tube seat, the substrate is arranged on the tube seat and located in the cavity, the field effect tube and the pyroelectric sensitive element are both arranged in the cavity, the field effect tube is installed on the substrate, the pyroelectric sensitive element is installed above the field effect tube, a plurality of pins are installed below the tube seat, the drain and source of the field effect tube are respectively connected to the corresponding pins, and the two ends of the pyroelectric sensitive element are respectively connected to the gate of the field effect tube and the pin ground, characterized in that: A second window is provided on the tube cap and an ambient light filter is installed on the window. A photosensitive element is installed in the cavity. An optical path is provided between the photosensitive element and the ambient light filter. An isolation cover is provided outside the optical path. The photosensitive element is connected to a corresponding pin or to a photosensitive element matching circuit, and the photosensitive element matching circuit is connected to the corresponding pin. The pyroelectric sensor with ambient light detection function is directly connected to the control unit, and outputs a human detection signal and an ambient light detection signal to the control unit at the same time. The control unit controls the execution unit to determine whether to turn on the lamp or adjust the luminous intensity of the lamp according to the algorithm. The isolation cover comprises an upper light-blocking column and a lower light-blocking column, the photosensitive element is mounted on a substrate, the lower light-blocking column cover is arranged outside the photosensitive element, the upper light-blocking column is mounted between the lower light-blocking column and the upper surface of the tube cap, and a light-guiding column is installed in the upper light-blocking column; the upper light-blocking column and the lower light-blocking column are concentrically arranged and connected to form an integrated structure; The isolation cover is a packaging cavity, the photosensitive element is installed in the packaging cavity, the packaging cavity is installed on the tube cap, and its upper surface exposes the second window or is flush with the second window, and the ambient light filter is installed on the upper surface of the packaging cavity; the packaging cavity is made of a material that is opaque to visible light; the packaging cavity is installed on the substrate through a column and is connected to the tube cap.

2. The pyroelectric sensor with ambient light detection function according to claim 1, characterized in that: The photosensitive element is a photoresistor, a photodiode, a phototransistor or a photosensitive integrated sensor.

3. The pyroelectric sensor with ambient light detection function according to claim 1, characterized in that: An impedance matching resistor is connected in parallel to the pyroelectric sensitive element.

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