JPH0425485B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to an infrared detector for detecting, for example, the temperature of a detected part using infrared rays.

(b) Prior Art Recently, an infrared detector as shown in FIG. 1 has been proposed.

1 is a pyroelectric infrared detector made of lithium tantalate (LiTaO ₃ ) single crystal, which has front and back electrodes 2 and 3 and generates a charge according to the amount of change in incident infrared rays; 4 is made of phosphor bronze, etc. A metal support, 5 a conductive adhesive, 6 a shield body for shielding the infrared detector 1 from external noise, and an opening 7 facing the detector 1 is bored in its front surface.

Reference numeral 8 denotes a storage body consisting of a metal cap 9 and a header 10, and the support base 4 is fixed on the header 10 inside the storage body. Reference numeral 11 is a ground terminal that is directly implanted in the header 10 and is electrically connected to the back electrode 3 via the support base 4 and adhesive 5; A signal terminal 13 is electrically connected to the surface electrode 2 and is used to take out the electric charge generated in the detection object 1 to the outside. A signal terminal 13 is provided on the front surface of the cap 9 to allow infrared rays to enter the detection object 1 from the surface electrode 2 side. The provided opening 14 is an infrared transmission filter that closes the opening.

15 is arranged in the storage body 8, and the opening 1
3 is an intermittent means for intermittent infrared rays from a detected portion outside the storage body 8 that passes through the infrared rays. In the disconnection means, 16 and 17 are planar first and second opposing bodies arranged in parallel to each other in the incident area of the infrared rays to the detection body 1, that is, between the detection body 1 and the opening 13. be. As shown in FIGS. 2a and 2b, these first and second opposing bodies 16 and 17 are made of an infrared opaque material such as aluminum, and are arranged in a fan-shaped linear shape in a direction substantially parallel to the plane of the paper (FIG. 1). A plurality of extended first infrared non-transmissive parts 18, 18... and second infrared non-transmissive parts 19, 19... are formed, and between each of the first infrared non-transparent parts 18, 18... A first infrared transmitting section 20, 20... and a second infrared transmitting section 21, 21... are formed between each of the two infrared non-transmitting sections 19, 19.... The non-transmissive parts 18, 18, . . . and 19, ₁₉ , . _. . and the transparent parts 20, 20, .

Reference numeral 22 denotes a first vibrating body for vibrating the first opposing body 16, and behind the vibrating body (FIG. 1) there is a second vibrating body for vibrating the second opposing body 17 as shown in FIG. A vibrating body 23 is arranged. The configurations of the first and second vibrating bodies 22 and 23 are as follows. That is, a conductor made of phosphor bronze, stainless steel, etc. serves as the central electrode 24, and on both sides of the electrode 24, polarized piezoelectric materials 25 made of barium titanate, lead zirconate titanate, etc. are placed in the direction of polarization (arrow). P) are arranged to be the same, and a surface electrode 26 made of silver or the like is formed on one surface of the piezoelectric body 25. 1st and 2nd above
The opposing bodies 16 and 17 are the first and second vibrating bodies 22,
Insulating first and second bases 27 and 28 are placed on the right end of 23.
It is attached via.

29 and 30 are insulating layers 3 on the header 10, respectively.
1 and the first and second vibrating bodies 2
2, 23, and are electrically connected to the surface electrodes 26, 26 of each vibrating body 22, 23.
The center electrode 24 of the first vibrating body 22 and the second fixing base 30 are connected to the first vibrating terminal, and the first vibrating terminal is connected to the first vibrating terminal 24 and the second fixing base 30. 2. The first fixed base 2 is attached to the second vibration terminal 33.
9 and the center electrode 24 of the second vibrating body 23 are connected.

A constant voltage of -20V is applied to the first vibration terminal 32, and a voltage of ±20V is applied to the second vibration terminal 33.
A voltage of 10V is applied alternately and periodically.

When such a voltage of +10V is applied, the outer piezoelectric body 25 of the first vibrating body 22 contracts and the inner piezoelectric body 25 expands, so that the first vibrating body 22
is bent in the direction of arrow a. Moreover, the second vibrating body 23
In this case, the inner piezoelectric body 25 expands and the outer piezoelectric body 25 contracts, so that the second vibrating body 23 bends in the direction of arrow b.

On the other hand, when a voltage of -10V is applied to the second vibrating terminal 33, the first and second vibrating bodies 22 and 23 bend in directions b and a, respectively, contrary to the above description.

As a result, the first and second vibrating bodies 22, 23
vibrate periodically in opposite directions, and based on such vibrations, the first infrared transmitting portion 2 of the first opposing body 16
0, 20... and the first infrared non-transmissive portions 18, 18...
and the second infrared opaque portion 19,1 of the second opposing body 17.
9... and the second infrared transmitting sections 21, 21... overlap each other, and the infrared transmitting sections 20, 20..., 2
1, 21... and infrared non-transmissive parts 18, 18
..., 19, 19... are repeated alternately, that is, the infrared rays from the external detected part that has passed through the opening 13 are intermittently incident on the detection object 1, and therefore the detection object 1 is The amount of incident infrared rays changes, generating a charge depending on the temperature of the detected part.

By the way, it is most preferable that the first and second vibrating bodies 22 and 23 have a completely symmetrical structure with respect to the center electrode 24. That is, in the case of such a structure, the average coefficient of thermal expansion of the respective structures on both sides of the center electrode 24 is the same, so that even if the ambient temperature changes, the first and second vibrating bodies 22, 23 Since it expands and contracts in the same way, it will not bend undesirably. In such a state where there is no deflection, when the first and second vibrating bodies 22 and 23 vibrate, the above-mentioned two
The two superimpositions are reliably repeated, and infrared rays are reliably switched on and off, thereby generating a desired charge from the detection object 1 in accordance with the temperature of the detected part, allowing highly accurate temperature measurement.

However, it is actually extremely difficult to obtain a completely symmetrical structure as described above. For example, it is difficult to match the thickness of the piezoelectric body 25 and the surface electrode 26 on both sides of the center electrode 24 with high accuracy. The average coefficients of thermal expansion of the structures will be different, and in this case, the first and second vibrating bodies 22 and 23 will undesirably flex due to changes in ambient temperature.

Therefore, in the above-mentioned infrared detector, the first,
Even if the second vibrating bodies 22 and 23 are deflected due to changes in ambient temperature, the mutual relationship between the first and second opposing bodies 16 and 17 does not change much compared to the case where there is no deflection as described above. The two vibrating bodies 22 and 23 are selected so that they bend to the same extent in the same direction a or b as the ambient temperature changes. However,
The first and second vibrating bodies 22, 23 due to changes in ambient temperature
In this deflection, the mutual relationship of the first and second opposing bodies 16, 17 actually shifts as shown in detail in FIG.

That is, since the first and second fixed bases 29 and 30 serving as fulcrums of the first and second vibrating bodies 22 and 23 are spaced apart on the header 10, the first and second vibrating bodies 22 and 23 When the first and second opposing bodies 16, 17 are deflected by a dimension l when referring to their center lines C and C', for example, if the deflection occurs in the direction a from the position indicated by the solid line to the position indicated by the broken line due to a change in ambient temperature.

In a state where such a deviation occurs, the above-mentioned two superpositions cannot be reliably performed when the first and second vibrating bodies 22 and 23 vibrate, so the infrared rays cannot be intermittent reliably. Detected object 1
Therefore, a desired charge corresponding to the temperature of the detected part is not generated, and accurate temperature measurement cannot be performed.

(C) Object of the Invention The object of the present invention is to ensure that infrared rays are intermittent, so that, for example, in temperature measurement, such temperature measurement can be performed with high accuracy.

(d) Structure of the Invention In order to achieve the above object, the infrared detector of the present invention comprises: an infrared detecting body that generates an electric charge according to the amount of change in incident infrared light; an infrared transmitting part disposed in the infrared incident area to the detecting body; first and second opposing bodies both having an infrared non-transmissive part; a state in which the infrared transparent part and the infrared non-transmissive part of the first opposing body overlap with the infrared non-transmissive part and the infrared transmissive part of the second opposing body, respectively; ,
First and second vibrations that vibrate the first and second opposing bodies, respectively, in order to alternately repeat a state in which the infrared transmitting parts and the non-infrared transmitting parts of the first and second opposing bodies overlap each other. comprising a body, the first;
The first and second vibrating bodies are arranged such that the surfaces perpendicular to the vibration directions of the second vibrating bodies are located on the same plane.

(e) Embodiment An infrared detector according to an embodiment of the present invention will be described below with reference to FIGS. 5 and 6. Incidentally, the same parts as in the conventional example are denoted by the same reference numerals, and the explanation thereof will be omitted.

Reference numerals 34 and 35 denote first and second vibrating bodies for periodically vibrating the first and second opposing bodies 16 and 17 attached to the lower and upper ends of the right side, respectively;
The second vibrating body is similar to the conventional one except that its piezoelectric body 25 is polarized in the P and P' directions, respectively.
36 is a plane perpendicular to the vibration directions a and b of the first and second vibrating bodies 34 and 35, respectively, so that A and B are located on the same plane. 25, and the first vibration terminal 32 has first and second vibration terminals.
The center electrodes 24 of the vibrating bodies 34 and 35 are connected, and the second vibration terminal 33 is connected to the fixing base 36.

Thus, a constant voltage of -20V is applied to the first vibration terminal 32, and a voltage of ±10V is applied to the second vibration terminal 33.
voltages are applied alternately.

When a voltage of +10V is applied, the first and second vibrating bodies 34 and 35 bend in directions a and b, respectively, and when a voltage of -10V is applied, the first and second vibrating bodies 34 and 35 bend in directions b and a, respectively. As a result, the first and second vibrating bodies 34 and 35 vibrate periodically as in the conventional case,
Infrared intermittent is performed.

Here, since the fulcrums of the first and second vibrating bodies 34 and 35 are on the same straight line at the fixed base 36 and are vertically overlapped, the first and second vibrating bodies 34 and 35
Even if the first and second facing bodies 16 and 17 are bent due to a change in ambient temperature, this will not cause any misalignment between the first and second opposing bodies 16 and 17.

Therefore, in a state where such deflection occurs, when the first and second vibrating bodies 34 and 35 vibrate, infrared rays are reliably interrupted, and a desired charge is emitted from the detecting body 1 according to the temperature of the detected part. is generated.

(f) Effects of the Invention As is clear from the above explanation, according to the present invention, infrared rays can be reliably interrupted even if the ambient temperature changes, so that it can be performed with high accuracy, for example, in temperature measurement. I can do it.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of a recently proposed infrared detector, Figures 2a and b are plan views of the first and second opposing bodies of the detector, respectively, and Figure 3 shows the same detector as in Figure 1. FIG. 4 is a plan view of the main part as seen from the direction of the arrow; FIG. 4 is a plan view of the main part for explaining the operation of the disconnection means of the detector; FIG. 5 is a sectional view of the infrared detector according to the embodiment of the present invention; FIG. is a plan view of the main part of the same detector as seen from the direction of the arrow. 1... Pyroelectric infrared detector, 16, 17... First and second opposing bodies, 34, 35... First and second vibrating bodies.

Claims (1)

[Claims] 1. An infrared detecting body that generates a charge according to the amount of change in incident infrared rays, first and second opposing bodies that are arranged in an infrared incident area to the detecting body and have both an infrared transmitting part and an infrared non-transmitting part, and the first opposing body. a state in which the infrared transparent part and the infrared non-transparent part of the body and the infrared non-transparent part and the infrared transparent part of the second opposing body overlap, respectively;
First and second vibrations that vibrate the first and second opposing bodies, respectively, in order to alternately repeat a state in which the infrared transmitting parts and the non-infrared transmitting parts of the first and second opposing bodies overlap each other. comprising a body, the first;
An infrared detector characterized in that the first and second vibrating bodies are arranged so that surfaces perpendicular to the vibration directions of the second vibrating bodies are located on the same plane.