JP2549297B2 - Infrared sensor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an infrared detector capable of detecting the directionality of an intruding human body.

(Prior Art) USP Nos. 3,355,589 and 3,839,640 are related to the conventional method for compensating the fluctuation of the atmospheric temperature of the infrared detector.
Although many materials are found, it does not have a plurality of sensing elements having independent output terminals.

U.S. is also well known as an infrared detector for video.
SP No. 4,214,165 is too expensive as a device for detecting the intrusion direction of the human body, which is the subject of the present invention, and is not suitable for service.

Furthermore, there is also a public utility model publication No. 152930 (1986) regarding a configuration in which infrared sensing light is reflected or blocked by a part of the infrared sensing element to inhibit the sensing effect of the element. Since it is not intended to detect the direction of an intruder, the sensitive parts are all located in the central part that is completely contrary to the case.

In this case, a temperature compensating element, which is not intended to sense infrared rays, is arranged in the central portion.

(Problems to be Solved by the Invention) In the present case, the infrared detector is intended to detect the intrusion direction of the human body and make an appropriate response according to the directionality.

For example, we installed this infrared detector at the store to generate a chorus sound for visitors (intrusion) and "Thank you very much" for returning customers (intrusion). It is used for the purpose of corresponding a response depending on the moving direction of the human body so as to generate a consonant sound.

(Means for Solving the Problem) In order to detect the moving direction of the human body more accurately on the wafer W of the infrared detecting element that must be housed in a limited space because it is built in the infrared detector. In the present invention, a temperature compensating element C, which is less affected by the incident light of infrared rays, is provided in the central portion of the wafer whose displacement is small, while infrared sensitive elements S ₁ , S ₂ ... S ₄ (S _N ). On the outer peripheral part with the maximum displacement, as shown in Fig. 1 (a) and (b) respectively.
They are arranged as shown in the front view in (c) and (d).

(Function) Among these, (b) is the two sensing elements S ₁ of the infrared detector.
It is suitable to be installed at a position where S and S ₂ are horizontal, such as a wall or a pillar of a person's doorway.

That is, when the movement of the person is from left to right as viewed in the drawing, the respective sensitive elements S ₁ and S ₂ are gates G ₁ and G ₂ entwined with the independent output terminals of (a) in FIG. Connected to.

As a result, first, after a human body detection signal is obtained from the output terminal connected to S ₁ , a signal is obtained from the output terminal connected to S ₂ after a minute time.

The direction of movement of the human body is known by recognizing which signal comes first among the two signals having the temporal deviation.

Since the reflection type mirror or lens for condensing light may be used alone or in common, the order of the output signals may not be arranged in the direction coincident with the moving direction. The purpose can be achieved by learning the arrangement and giving a response signal suitable for the direction.

(Embodiment) Similarly, FIGS. 1 (a), (c), and (d) show the sensing elements S ₁ , S ₂ , which are suitable for being installed on the ceiling of the space where a person moves.
This is the arrangement of S ₃ and S ₄ .

In principle, the description is omitted because it is the same as the type (b) described above.

FIG. 2 shows all one or many pyroelectric wafers W.
FIG. 3 is a vertical cross-sectional view of an infrared detection element configured from.

Electrodes for temperature compensating elements are arranged at the center of one wafer W, and infrared sensitive elements are positioned outside both of them to provide the output signals to the respective gates G ₁ and G ₂ .

The difference between these figures (a) and (b) is that the former is a process for reflecting or (and) blocking infrared energy on the upper side of an independent central compensating electrode, and the latter is a common electrode. Part of the above is processed in the same manner as the former.

Further, FIGS. 2 (c) and 2 (d) show the electrical connection relationship between the infrared sensitive element S _N composed of a plurality of wafers W and the temperature compensating element C.

The arrows inside the wafer indicate the direction of their polarization.

All of these directions show typical directions, and if the simultaneity is maintained in each direction, the reverse polarity does not cause any problem.

All of the electrical connections of the sensitive element and the temperature compensating element are arranged in series with opposite polarities in the drawings, but the objects can be almost the same even if they are connected in parallel.

That is, the difference between the series and the parallel is only a slight difference between the sensitivity level and the noise level, and it has a temperature compensation function that is a feature of the present invention and has a moving directionality, but is compared with an image sensor. Therefore, there is no problem with items such as being extremely inexpensive.

(Effects of the Invention) Since the infrared detectors according to the present invention are arranged at the positions where the distance between the sensing elements is maximum, the direction of movement of the human body can be detected with higher accuracy, and the sensing elements of those elements can be detected. Since the temperature compensating element is arranged in the central portion of the, the interference between the infrared sensitive elements facing each other is suppressed, and the direction of movement of the human body can be detected more clearly.

Because of these features, many infrared detectors that can be set in a store where the temperature changes relatively indoors or where the response is different depending on the moving direction of the human body, such as the entrance, It is industrially valuable because it can be applied.

[Brief description of drawings]

1 (a), (b), (c), and (d) are model front views of the positional relationship between the sensitive elements S ₁ , S ₂ ... _SN and the temperature compensating element C of the infrared detector of the present invention. It is shown in. 2 (a) and 2 (b), the sensing elements S ₁ and S ₂ and the temperature compensating element C are arranged on one wafer W, (c) is independent, and (d) is compensation. It is a sectional view showing a state in which only the device C is common.

Claims (1)

(57) [Claims] 1. An infrared sensor characterized in that a temperature compensating element is arranged at the center of a plurality of infrared sensitive elements having independent output terminals.