JPH11108754A - Infrared human body detecting sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a human body detecting sensor which is resistant to the change of environment by the incidence of sunlight and allows the precise detection of a human body without complicating the structure of a judgment circuit for judging whether the human body is present or not. SOLUTION: This detecting sensor is provided with an optical system 1 for converging infrared rays, an infrared detecting element 2 in which at least one set of elements 21 (21a, 21b) mutually differed in polarity for detecting the infrared dose converged by the optical system 1 is arranged, and a judging circuit 4 for determining the total sum of the output voltage outputted from each element 21 in the infrared detecting element 2 and outputting a detection signal when it exceeds a predetermined judgment range.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an infrared type human body detecting sensor for detecting infrared rays emitted from a human body by an infrared detecting element and detecting movement of a human.

[0002]

2. Description of the Related Art There are pyroelectric elements, thermopiles, bolometers, thermistors, and the like as elements for detecting a human body by a change in heat radiated by the human body.

A pyroelectric element (hereinafter, this infrared detecting element is referred to as A
The C-type infrared detection element is a non-contact type temperature sensor that detects a change in the amount of heat generated when a human body enters. On the other hand, infrared detecting elements such as thermopiles and thermistors (hereinafter, these infrared detecting elements are referred to as DC-type infrared detecting elements) are non-contact type temperature sensors that detect the amount of heat radiated from a human body. Therefore, the AC-type infrared detection element does not output a signal if the change in the amount of heat is not detected even if a human body is present. Even if there is, it outputs a signal based on the amount of heat radiated from the human body.

Next, a configuration and a detection method of an infrared human body detection sensor using a DC type infrared detection element will be described with reference to FIG.

[0005] An infrared human body detection sensor using this DC type infrared detection element is mounted on a ceiling or the like of a passage as shown in FIG.

The optical system 1 comprises a lens or a mirror. The optical system 1 is used to form a plurality of detection areas, which are detection fields of a human body, from the infrared type human body detection sensor to the floor. Become.

The infrared detecting element 2 is a DC type infrared detecting element having either positive or negative polarity, and whose output value varies with a temperature change in the detection area.
It is configured using one to four element elements 21 (see FIG. 3B). When a human body enters the detection area, infrared rays radiated from the human body are focused on the element element 21 via the lens. When infrared rays are detected by the infrared detecting element 2, the output value rises or falls according to the polarity.

The output value output by the collected infrared light is amplified by a signal amplifier 3 composed of an amplifier and the like. It should be noted that unnecessary signal components are removed from the amplified signal components using a filter or the like in consideration of the incident infrared rays and the frequency characteristics of the infrared detection element 2 in order to suppress disturbance noise and obtain an effective output. You may make it.

The determination circuit 4 determines the presence or absence of a human body based on the output voltage obtained by the signal amplifier 3. As a determination method, a threshold value is determined in advance, and when the output voltage exceeds the threshold value, it is determined that a human body exists. When it is determined that a human body is present, a detection signal is output from the determination circuit.

[0010]

In the infrared type human body detection sensor having the above-mentioned structure, as shown in FIG.
If the output voltage of the signal amplifying unit 3 becomes higher than a predetermined threshold value when sunlight enters the detection area or when there is a temperature change due to wind, an air conditioner, or the like, the infrared detecting element 2
, A detection signal may be output in spite of the absence of a human body (see FIG. 5B). However, it is very difficult to determine the difference between the temperature change due to the incidence of sunlight or the like and the temperature change due to the human body, and the determination circuit 4 has a problem that it becomes complicated. I was

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to determine whether a human body is present and is resistant to environmental changes due to the incidence of sunlight. It is an object of the present invention to provide a human body detection sensor that can accurately detect a human body without making the determination circuit complicated.

[0012]

According to the first aspect of the present invention,
An optical system for condensing infrared light, an infrared detecting element including at least one set of element elements having different polarities for detecting the amount of infrared light condensed by the optical system, and each of the element elements in the infrared detecting element And a determination circuit that outputs a detection signal if the sum of the output voltages output from the control signal exceeds a predetermined determination range.

According to a second aspect of the present invention, in the infrared type human body detection sensor according to the first aspect, when a human body crosses a detection area formed by the optical system and the element element, the detection is blocked by the human body. The area of the region is substantially equal to or smaller than the size of the human body.

According to a third aspect of the present invention, in the infrared type human body detection sensor according to the first or second aspect, an interval between the adjacent detection areas on the floor is larger than a width of a human. It is a feature.

According to a fourth aspect of the present invention, in the infrared type human body detection sensor according to the first to third aspects, the first determination range includes the first determination range and is wider than the first determination range. A second determination range having a range width is determined in advance, and the elapsed time from when the sum of the output voltages output from the respective element elements exceeds the first determination range to when the sum exceeds the second determination range Is measured and compared with a predetermined time set in advance, and if the elapsed time is within the predetermined time, a detection signal is output from the determination circuit.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to FIGS. FIGS. 1A and 1B are diagrams showing a configuration of an infrared human body detection sensor, FIG. 1A is a block diagram thereof, FIG. 1B is a diagram showing an arrangement of element elements of an infrared detection element, and FIG. FIG. 4 is a diagram illustrating a relationship between time when a light beam enters and an output voltage. 2A and 2B are diagrams illustrating a relationship between time and an output voltage, FIG. 2A is a diagram illustrating a time when a human body moves, and FIG. 2B is a diagram illustrating a time when an environmental temperature changes.

The infrared type human body detection sensor comprises an optical system 1 such as a lens, an infrared detection element 2, a signal amplifier 3 including an amplifier and the like, and a determination circuit 4. FIG.
In FIG. 7, the same reference numerals are given to the same parts as those of the infrared type human body detection sensor shown in FIG. 3 described in the related art, and the detailed description thereof will be omitted.

The infrared detecting element 2 is constituted by a DC type infrared detecting element, and is constituted by arranging one or a plurality of pairs of an element element 21a having a positive polarity and an element element 21b having a negative polarity. (See FIG. 1B). The amount of change in the value output by the paired element element 21 has substantially the same absolute value for the same input.

The judgment circuit 4 calculates the sum of the output voltages output from the infrared detecting element 2 and outputs a detection signal when the sum is larger or smaller than a value in a predetermined range (hereinafter referred to as a judgment range). Is what you do.

According to the infrared type human body detection sensor having this configuration, when a human body enters, it does not enter the detection areas formed by the element elements 21 having different polarities at the same time. A detection signal is output from the determination circuit 4 when the value deviates from the determined determination range.

On the other hand, when the temperature of the environment changes due to the incidence of sunlight, an air conditioner, or the like, as shown in FIG. 1C, signals are output from all the element elements 21 and the polarities are different from each other. Since the outputs of the element elements 21 cancel each other, it is possible to prevent an erroneous detection signal from being output assuming that a human body exists even though the human body does not exist.

If the area of the detection area that crosses when the human body moves is made smaller than the width or height of a person, the amount of infrared light that enters the infrared detection element 2 per unit area increases. It is possible to reduce the time until a human body is detected. Further, if the distance between the detection regions having different polarities is made larger than that of a human, the human body is simultaneously present in both the detection regions, and the outputs of the element elements 21 having different polarities do not cancel each other. .

Further, in the judgment circuit 4, a first judgment range and a second judgment range including the first judgment range and having a wider range than the first judgment range are determined in advance. The elapsed time t from when the sum of the output voltages output from the detection element 2 exceeds the first determination range to when the sum exceeds the second determination range is measured and compared with a predetermined time T that is set in advance. Alternatively, if the elapsed time t is within the predetermined time T, it may be determined that a human body exists (see FIG. 2). This makes it possible to detect a human body with higher accuracy by making use of the fact that the temperature change caused by a change in the environment is more gradual than the temperature change caused by the movement of the human body.

[0024]

As described above, according to the first aspect of the present invention, at least the optical system for collecting infrared rays and the element elements having different polarities for detecting the amount of infrared rays collected by the optical system are provided. Since one set of infrared detection elements and a determination circuit that calculates the sum of the output voltages output from the element elements in the infrared detection element and outputs a detection signal when the detection voltage exceeds a predetermined determination range,
When the environment changes due to the incidence of sunlight, etc., since the output voltages are offset by the element elements having different polarities, the device is resistant to the environment change due to the incidence of sunlight,
In addition, a human body detection sensor that can accurately detect a human body without requiring a complicated configuration of a determination circuit that determines whether a human body exists is provided because a complicated determination standard is not required. It has the effect that it can be done.

According to the second aspect of the present invention, there is provided the first aspect.
In the infrared human body detection sensor described above, when the human body crosses the detection area formed by the optical system and the element element, the area of the detection area blocked by the human body is substantially equal to or smaller than the size of the human body. With this configuration, the amount of infrared light incident on the infrared detection element per unit area increases, so that it is possible to reduce the time required for detecting a human body. In addition, if the area of the detection region blocked by the human body is substantially the same as the size of the human body, the human body exists in the detection regions having different polarities at the same time, and the outputs of the element elements having different polarities cancel each other. Can be avoided.

In the invention according to claim 3, claim 1 is
Or in the infrared human body detection sensor according to claim 2,
Since the interval between adjacent detection areas on the floor is set to be larger than the width of a human, the human body is simultaneously present in the detection areas having different polarities, and the outputs of the element elements having different polarities are mutually canceled. This makes it possible to avoid a situation in which a detection signal is not output despite the presence of a human body.

According to the fourth aspect of the present invention, the first aspect is provided.
The infrared human body detection sensor according to claim 3,
A first determination range and a second determination range including the first determination range and having a wider range than the first determination range are determined in advance, and the sum of output voltages output from the element elements is determined. Exceeds the first judgment range,
The elapsed time until exceeding the judgment range is measured and compared with a predetermined time set in advance.If the elapsed time is within the predetermined time, a detection signal is output from the judgment circuit, so that the movement of the human body By utilizing the fact that the temperature change caused by the change in the environment is more gradual than the temperature change caused by the change in the environment, it is possible to perform a human body detection that is more resistant to the change in the environment.

[Brief description of the drawings]

FIGS. 1A and 1B are diagrams showing a configuration of an infrared human body detection sensor, FIG. 1A is a block diagram thereof, FIG. 1B is a diagram showing an arrangement of element elements of an infrared detection element, and FIG.
FIG. 4 is a diagram illustrating a relationship between a time when sunlight enters and an output voltage.

FIG. 2 is a diagram illustrating a relationship between time and an output voltage;
(A) is a figure showing the time of a human body movement, (b) is a figure showing the time of environmental temperature change.

3A and 3B are diagrams illustrating a configuration of a conventional infrared human body detection sensor, in which FIG. 3A is a block diagram, and FIG. 3B is a diagram illustrating an arrangement of element elements of an infrared detection element.
(C) is a diagram illustrating a relationship between a time when a human body enters and an output voltage.

FIG. 4 is a perspective view illustrating a relationship between an installation position of an infrared human body detection sensor and a detection area.

5A is a perspective view showing a relationship between an installation position and a detection area of a conventional infrared human body detection sensor and showing a state where sunlight enters, and FIG. 5B is a perspective view showing a state where sunlight enters; FIG. 5 is a diagram showing a relationship between the time and the output voltage.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Optical system 2 Infrared detecting element 21 Element element 4 Judgment circuit

Claims (4)

[Claims] 1. An infrared detecting element comprising: an optical system for collecting infrared light; at least one set of element elements having different polarities for detecting the amount of infrared light collected by the optical system; and the infrared detecting element. A detection circuit for obtaining a sum of output voltages output from the respective element elements and outputting a detection signal if the output voltage exceeds a predetermined determination range. 2. When a human body crosses a detection area formed by the optical system and the element element, the area of the detection area blocked by the human body is substantially equal to or smaller than the size of the human body. The infrared human body detection sensor according to claim 1, wherein 3. The infrared human body detection sensor according to claim 1, wherein an interval between the adjacent detection areas on the floor is larger than a width of a human. 4. A first determination range and a second determination range that includes the first determination range and has a wider range than the first determination range are determined in advance, and output from each of the element elements is determined. The elapsed time from when the sum of the output voltages exceeds the first determination range to when the sum exceeds the second determination range is measured and compared with a predetermined time set in advance. 4. An infrared human body detection sensor according to claim 1, wherein a detection signal is output from said determination circuit.