JPS5973742A - Infrared ray detecting device - Google Patents

Abstract

PURPOSE:To maintain high accuracy in detecting infrared rays, by providing a temperature detector, which outputs a DC signal for biasing a vibrator in DC based on the detected temperature of the vibrator, providing a specified voltage applying means, which applies a specified voltage to the vibrator at a desired time, and ensuring the change in the amount of incident infrared rays to an infrared ray detecting body at a specified difference. CONSTITUTION:A numeral 58 is an oscillator comprising an astable multivibrator. A numeral 62 indicates a control part comprising a micro-computer and the like, which outputs a temperature display signal D based on a digital signal from a conveter 61 and pulses from said oscillator 58. A very large specified voltage -60V from a constant voltage applying circuit 59 is applied to a first vibrating elecrode at every 5 seconds. Then, a bimorph 30 is deflected to the direction B very largely as shown by the hysteresis characteristic every time. When -60V is applied, the bimorph 30 is deflected to the direction A along a line H with good reproducibility based on a desired bias voltage. Therefore, the deflecting amount of the bimorph 30 is sequentially corrected at every 5 seconds even though the bimorph is under the deflected state due to the decreasing trend of the bias voltage. That is, a second infrared ray transmitting part is corrected so that a first infrared ray transmitting part is completly overlapped with a first infrared ray stopping part. The decrease in the amount of infrared rays that is inputted to an infrared ray detecting body 2 is suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to an infrared detection device for detecting infrared rays from an object to be detected in order to measure the temperature of the object.

(b) Prior Art Recently, an infrared detector (1) as shown in FIG. 1 has been proposed. (2) is lithium tantalate (LiTa03)
A pyroelectric infrared detector that is made of a single crystal and generates a charge according to the amount of change in incident infrared rays; (3) and (4) are formed on a nichrome vapor-deposited film on the front and back surfaces of the infrared detector, respectively. The front and back i electrodes (5) are metal supports made of copper or phosphor bronze.
) so as to face the upper surface of the support stand (5) - C1' bipedal infrared detector (2) with conductive adhesive such as silver paste (
6) is fixed.

<7) Since the infrared detector (2) has a high resistance, the infrared detector (1) is made of aluminum in which an impedance conversion circuit (8) is arranged to make the infrared detector (1) have a low resistance!). plate, (9) is a metal kill knob (10) and header (1
A storage body consisting of 1〉, with 7 da
) on which the support stand (5) and the substrate (7) are fixed. (12) is a ground terminal directly implanted in the /\anda (11), and this terminal is electrically connected to the back electrode (4) via the support base (5) and adhesive (6). It is connected to the. (13) and (14) are the above header (
11) first and second lead terminals implanted through insulating materials (15) and (16); (17) is the surface electrode (3);
The lead wires (18) and (19) connect the impedance conversion circuit (8) and the first and second lead terminals (13) and (14). The connection is a single lead wire.

(20> is an opening formed in the camp (lO) to allow infrared rays to enter the infrared detector (2) from the surface electrode (3) side, and (21) is an infrared transmitting body that closes the opening. The transmitting body is made of 11 silicon or gel manila plates several 100 μm thick that have a high transmittance to infrared rays having a wavelength of 2 to 15 μm.

(22) is a shield body made of aluminum or the like and covers the infrared detector (2) and the impedance conversion circuit (8), and (23) is the part of the shield body located above the detector (2). It is a drilled opening.

(24> is a planar first opposing body attached to the opening,
As shown in FIG. 2a, the first opposing body includes an aluminum ram,
It is made of a material that does not transmit infrared rays, such as gold or silver, and extends in a fan-shaped line in a direction parallel to the paper (Figure 1). a plurality of first infrared non-transmissive parts (25>, (25), , ).

and such first infrared opaque portion (25), (25)19.
The first infrared transmitting portion (26), located between each of (2)
6) is completely formed. Then, the first infrared opaque portion (25), (25)1. The widths W1 and W2 of , respectively, are 1
00 μm, 120 μm, and the first infrared transmitting portion (26
〉, (26)5. The widths Wl and W2' are the above W1 and W
It has the same dimensions as 2. (27) is the first opposing body (24
), and the second opposing body has the first infrared non-transmissive portions (25), (25) as shown in FIG. )1. A plurality of second infrared non-transmissive parts (28), (28
), .

and a second infrared non-transmissive part (28), (28>, ,
a second infrared transmitting section (29) located between each of the
(29)11. is formed. And”-2 2nd
Widths Wl, W of the infrared opaque parts (28), (28),
2 and the second infrared transmitting portion (29), (29),
, the widths Wl' and W2' of the first infrared non-transmissive portion (
25), (25)10. widths Wl, W2 and the first infrared transmitting portions (26), (26),.

The dimensions are the same as the widths Wl' and W2'.

(30〉 is a vibration f formed by laminating two piezoelectric plates made of ferroelectric material or a metal plate and a piezoelectric plate made of ferroelectric material, that is, a bimorph, and the bimorph has a straight body shape and its length P, width w1 thickness a (Fig. 3) are respectively 30
m+, 5nwn, Q, 5m1i. Examples of the piezoelectric plate include quartz crystal, Rochelle salt, halium titanate, and the like. The -F bimorph (30) is elongated in the direction perpendicular to the direction of the infrared radiation, that is, in the horizontal direction, and its left end (30') is attached to the insulating stand (31) provided on the header (11). The second opposing body (27) (1) is installed on the right end (30"). The three lead terminals (34) and (35) are first and second vibrating electrodes formed on both sides of the left end (30') of the bimorph (30), as shown in FIG. The two vibrating electrodes are connected to the third lead end -r (32') and the header (11), respectively.
(Connected to the ground terminal (12>). <36) is a support made of resin such as Teflon, and the support
A skin (37) is carved to slidably support the free end (27') of the second opposing body (27).

The first vibrating electrode (34) is supplied with a predetermined alternating current voltage, that is, the periodic pulse voltage 4, through the third lead terminal (32).
If such a pulse is not applied, the second infrared non-transmissive portion (28) of the second opposing body (27) <28>191. ” bipedal first opposing body (24
) in the first infrared transmission μ part (26〉, (26), ), which is completely heavy JE, (located in the sublined region J of FIG. 2C).

When the pulses C and G are applied, the above high-
[-Luno (30) is bent in the incoming direction, and the second infrared non-transmissive part 〈28), (28)1. is the first infrared opaque part (25)
, (25), which completely overlaps and is located in the dot area 1 of FIG. 2C). Therefore, by periodically applying pulses to the first vibrating electrode (34), the bimorph (30) periodically vibrates in directions A, B, and the infrared detector (2) detects infrared rays. Infrared rays from an object to be detected externally enter the detector (1) periodically. When such incidence is made, the infrared meter incident on the infrared detector (2) changes periodically, so the infrared detector (2) generates a charge corresponding to the amount of change. This charge is based on the temperature difference between the temperature of the object to be detected and the room temperature (temperature of the second opposing object (27)).

Fig. 4 shows the circuit of the infrared detection device including the above-mentioned infrared detector (1), and the impedance conversion circuit (8) in the infrared detector (1) has a high input resistance (38) of 10'0 to 1011Ω, FET (field effect transistor) (39) and an output resistor (40) of approximately 10Ω.

The infrared detector (1) is connected to the first lead end r-(
13), a DC voltage is supplied to the bimorph (30
), an AC signal e as shown in FIG. 5a is output from the second lead terminal (14) with an amplitude corresponding to the temperature difference between the temperature of the object to be detected and the room temperature. 41) is a room temperature diode that measures room temperature and outputs a DC signal according to the room temperature;
(42) is an oscillator consisting of an astable multi-by-break, which oscillates a pulse f with a voltage V of 1 to 30 V, preferably 14 V, at a frequency of 20 Hz, as shown in Figure 5; a drive circuit that outputs periodic pulses that cause the bimorph (30) to vibrate;
(44>, (45), (46) are DC amplifiers, (47>
is a Noirtor amplifier, and (48) is a synchronous detector, which synchronizes the AC signal e from the infrared detector (1) with the pulse f from the oscillator (42), and detects the detected object. When the temperature is higher than room temperature, a positive DC signal is output according to the temperature difference, and when the temperature of the object to be detected is lower than room temperature, a negative DC signal is output according to the temperature difference.

That is, the output AC No. 18 e of the infrared detector (1) is a positive half cycle e+ when the temperature of the object to be detected is higher than room temperature.
coincides with the pulse f, and when the temperature of the object to be detected is lower than room temperature, the negative half cycle e- coincides with the pulse r. and,
When the coincidence between the pulse f and the positive half cycle C+ is 1'L, the synchronous detector (48) outputs a positive DC signal corresponding to the temperature difference between the detected object and the room temperature, and the pulse r and negative (
When a match is established with II half-nicle e-, a negative DC signal corresponding to the temperature difference between the object to be detected and the room temperature is output.

(49) is a synthesis circuit that adds together the DC signal from the synchronous detector (48) and the DC signal corresponding to the room temperature of the room temperature diode (41). It outputs a zero signal corresponding to the temperature.(50) is the 4th/-th output terminal f which outputs the temperature signal to decline to the desired circuit.

In addition, the vibration state of the bimorph (30〉) above is when the room temperature is maintained at the desired temperature T'C, and the room temperature is 10-1- compared to the desired temperature T'C. When the bimorph (30) goes up or down, the vibrational state of the bimorph (30) changes significantly compared to the above.That is, if the room temperature rises above the desired temperature, the bimorph (30) Even when the pulse r is not generated, it is deflected by the dimension m in the B direction,
As shown in FIG. 2d, the second infrared non-transmissive portion <28)
8>, , , are located in the shaded area J' and do not completely overlap with the first infrared transmitting portions (26), (26), , , , , and the infrared rays from the object to be detected are located in the infrared detecting object (2). ). When the pulse f is generated, the second infrared opaque portions (28), (28) 111.
is the first infrared non-transmissive part (25) located in the dot area I'.
,〈25)1. The infrared rays from the object to be detected do not completely overlap with each other, and the infrared rays from the object to be detected are not sufficiently incident on the infrared detecting object (2). As a result, the change in the incident infrared radiation of the infrared detector 2) is significantly reduced, and the output of the infrared detector (1) becomes smaller as shown in the AC signal e' in Fig. 5a, and becomes an AC signal e having the desired amplitude. Therefore, the detection accuracy of the infrared detection device is significantly reduced.

-℃・, -J- The light distribution external ray detection device further has the following configuration. 4 lead terminal, (5
3) detects the temperature of the bimorph (30) and outputs a DC voltage based on the detected temperature, and is placed near the bimorph (30) in the storage body 9). The anode of the guide F for the heimorph is connected to the fourth lead terminal (51), and the cathode is connected (grounded) to the header (11).

(54) is a differential amplifier, and the anode of the bimorph diode (53) is connected to the fourth input terminal r- of the amplifier.
It is connected via a lead terminal (51), and a variable resistor (55) is connected to the input terminal. In such a variable resistor (55), the DC voltage applied to the input terminal of the differential amplifier 54) is equal to the DC voltage applied to the input terminal when the bimorph temperature is the desired temperature T'C. A desired resistance value is set in advance so that

(56) is an inverter which inverts the output of the two-legged differential amplifier (54). The output of the inverter is 0 when the temperature of the bimorph (30) is T''C, and on the other hand, when it is higher than T''C, for example, its J:: y+,
The voltage BS based on the temperature is also output as shown in FIG. 5C. 57 is an adder constituting the drive circuit (43), and in this adder, the DC voltage BS from the inverter (56) of the pulse f from the oscillator (42) is as shown in FIG. 5d. The summed output is applied to the first vibrating electrode (34).

, -, the bimorph (30) is in a state where the DC bias is cut off at the voltage BS, and with this state as a reference, it vibrates periodically in the A and B directions based on the pulse r.Here, , the above-mentioned bimorph (30) has a dimension m (21st Ad) I knee in the A direction in the DC bias state mentioned above, and as a result, the bimorph (30) in the B direction due to the temperature increase compared to the temperature T'C. Therefore, as shown in FIG.

1) Periodically located in the point area I and the shaded area J゛,
The infrared rays incident on the infrared detector (2) are completely blocked, and the infrared detector (1) outputs a second-stream signal e as shown in FIG. 5a.

However, the bimorph (30) has a relationship between the applied voltage and the deflection [
It has a hysteresis characteristic as shown in Fig. 6 between
Depending on whether the applied voltage has increased or decreased, there will be a difference in the deflection even with the same applied voltage. However, the bending of the bimorph (30) in the incoming direction
is generated when the bias voltage BS as the applied voltage follows an increasing trend along the line H. Conversely, if the bias voltage BS follows the increasing trend along the line h1. h211. When the bimorph (30) follows a decreasing trend along the direction of , the amount of deflection of the bimorph (30) becomes larger than m. Then, in the second case as well, the second infrared non-transmissive parts (28>, (28), , , ) are the first infrared transparent parts (26), (26) 110.
25), (25), 5. Therefore, the incident infrared ray change !I!' of the infrared detector (2) decreases, and the detection accuracy of the infrared detector decreases.

(C) Embodiments The present invention has been made in view of these points, and embodiments of the present invention will be described below in detail with reference to the drawings. Incidentally, the same parts as in the conventional example are denoted by the same reference numerals (description thereof will be omitted).

In FIG. 7, (58) is an oscillator consisting of an astable multivibrator, and this oscillator periodically oscillates a pulse having a width of I×10 3 to 1 second every 5 seconds. (59) is based on a reject pulse with a very large predetermined voltage of 1 [voltage -60 V [such voltage does not appear as a bias voltage BS in the normal sensing state of the diode (53)]] with a width of 1.
×103 to 1 second and oscillates every 5 seconds, and the 60V pulse is applied to the first vibrating electrode (34) of the bimorph (30).
), a predetermined voltage application circuit (60) sends the output of the Kaga device (54) to the first vibrating electrode (34) when no pulse is generated from the oscillator (58);
When the pulse is generated, the switch circuit (61) sends the output of the predetermined voltage applying circuit (59) to the first vibrating electrode (34), and the switch circuit (61) outputs the signal appearing at the output terminal (50).
An A-D (Ana L1 Gaede, Tal) converter (62) converts into a digital signal a temperature indicating signal based on the tental signal υ from the converter and the pulse from the alternating oscillator (58). A controller (63) is a display device that displays the temperature based on the temperature display signal that is rejected.

Facing 10, an extremely large predetermined type pulse of LJ>60V from the predetermined voltage application circuit (59) causes the first vibration'
1" is applied to the pole (34) every 5 seconds, each time the bimorph (30) exhibits the hysteresis characteristic shown in FIG. 6.
After applying -60V, the pi-self (30) deflects in the direction A with good reproducibility along the line H based on the desired bias voltage. Therefore, Even if the bimorph (30) is in a deflected state due to the decreasing tendency of the knee BS, the deflection will be corrected every 5 seconds, that is, the second infrared non-transparent part (28) (28>11. is the first infrared transmitting part (26), (26), and the first infrared non-transmitting part (25)
), (25), can be corrected so as to be completely superimposed on -, and the change 11 in the incident infrared rays on the infrared detector (2) is reduced or suppressed.

, -, the control unit (62) displays the temperature on the display (63) based on the signal from the A-D converter (61) in the absence of pulses from the oscillator (58), and the oscillator (58) When the pulse from the oscillator (58) is generated manually, the temperature display is stopped and raised.In other words, when the pulse is generated from the oscillator (58), the bimorph (3o) is deflected extremely greatly in the B direction, and the infrared rays are incident on the infrared detector (2). This is because the intermittent infrared rays are no longer in the desired state, resulting in poor detection accuracy.

In the two-legged embodiment, the room temperature diode (41) and the bimorph diode (53) are each provided separately, or the detected temperature of the bimorph diode (53) is determined by the temperature inside the housing (9). Since this temperature is equal to room temperature (the temperature of the second opposing body (27)),
O1: Omit (41) -C High E Luf's Gui'' -1・
(53) can also serve as the room temperature diode 1' (41).

(d) Effects of the Invention As is clear from the explanation in ``Effects of the Invention'', the infrared detection device of the present invention can cause a person q + infrared change! An infrared detecting body that generates an electric charge in accordance with the energy of
A pair of opposing bodies vibrate when an AC signal is applied, L 3
The state in which the infrared transmitting part and the infrared non-transmitting part of the opposing body of j and the infrared transmitting part of the other opposing body are clearly visible, and the infrared transmitting part and the infrared transmitting part of the pair of opposing bodies 1-2. Detect the temperature of the vibration r-1 to alternately repeat the state in which the infrared opaque part and the infrared rays are superimposed. Based on the detected temperature, - a temperature sensor that outputs a direct current signal from the radiator, and a predetermined voltage applying means for applying a predetermined voltage to the vibrator at a desired time, so that the amount of infrared rays incident on the infrared detector reliably changes with a predetermined difference; Therefore, extremely high infrared detection accuracy can be maintained.

[Brief explanation of drawings]

Figures 1 to 6 show recent infrared detection devices.
The figure is a cross-sectional view of the infrared detector, Figures 2 a, b, c, and d are plan views of the main parts, respectively, Figure 3 is a view seen from the direction of arrow ■ in Figure 1, Figure 4 is a circuit diagram, and Figure 4 is a circuit diagram. Figure 5 a, b, c, d are the fourth
FIG. 6 is a diagram of the hysteresis characteristics of a bimorph, and FIG. 7 is a circuit diagram of an infrared detection device according to an embodiment of the present invention. (2)・Infrared detector, (9)・Storage body, (20)・
...Opening, (24)...First opposing body. (25), (25), ... first infrared non-transmissive part, (
26), (26),...first infrared transmitting section, (27)
...Second opposing body, (28), (28), ...Second infrared non-transmissive part, (29
), <29), ... second infrared transmitting section, (30).
・Bimorph, (53)・Diode for bimorph, (59)・15
r Constant voltage application circuit. l', :,”,, ′ Figure 2 mouth====Co-mine

Claims (1)

[Claims] (1) an infrared detector that generates a charge according to the amount of change in incident infrared radiation; a pair of opposing bodies that are arranged in an infrared incident region to the detector and have both an infrared transmitting part and an infrared non-transmitting part;
a state in which the infrared transmitting part and the infrared non-transmitting part of the one opposing body are superimposed on each other, and the infrared non-transmitting part and the infrared transmitting part of the other opposing body are vibrated by the application of an AC signal, and the pair of bodies are oriented A vibrator for alternately repeating a state in which infrared transmitting parts of the body and non-infrared transmitting parts overlap each other; An infrared detection device characterized by comprising: a temperature detector that outputs a DC signal for DC bias; and a predetermined voltage applying means for applying a predetermined voltage to the vibrator when desired.