JPS5946826A - Infrared-ray detector - Google Patents

Abstract

PURPOSE:To interrupt exactly infrared rays made incident to an infrared-ray detecting body without being affected by room temp. (the temp. of an oscillator to increase the precision of detection, by providing a temp. detector outputting a DC signal for DC-biasing the oscillator. CONSTITUTION:A diode 56 for bimorph functioning as a temp. detector arranged in the vicinity of a bimorph 33 of an infrared-ray detector 4 is connected to a differential amplifier 57, an output of an inverter 59 is OV in such a case that the temp. of the bimorph 33 is 25 deg.C and positive DC voltage caused by raised temp. of 5 deg.C is outputted in the case of 30 deg.C, added with a pulse from the oscillator 45 by an adding device 60 and impressed to the first oscillating electrode 37. The bimorph 33 becomes the DC-biased state by DC voltage and bends to the A direction, the infrared-ray untransparent part of an opposing body 30 is situated circumferentially movably at the infrared-ray transparent part of an opposing body 27, and the infrared rays made incident to the infrared-ray detecting body 5 are intercepted perfectly.

Description

[Detailed description of the invention] (b) Industrial application fields The present invention relates to an infrared detector.

(B) Prior art and its problems In recent infrared detectors, for example, a current collecting type infrared detector is built into the infrared detector.

Such an infrared detector has the property of generating electric charge based on the amount of change in incident infrared light, and the detection accuracy of the infrared detector increases within a radius where the change in the incident infrared light level is periodic. It is necessary to periodically interrupt the infrared rays incident on the detection object, and for this purpose, as shown in Figure 1 a and b, the Mij side of the infrared detector (1) is periodically driven to rotate by a motor (2). The metal tip 3/bar (3) is fully placed.

However, such a chomba (3) is large in shape and poses a problem in terms of space.

Therefore, an infrared detector (4) as shown in FIG. 2 has been devised. In the same figure, (5) is tantalic acid') f
A pyro-IE type infrared detector, which is made of (LiTaO3) single crystal and generates a charge according to the amount of change in incident infrared rays;
6) and (7) are front and back electrodes formed on the front and back surfaces of the infrared detector using Nicroc vapor deposition films, respectively; (8) is copper;
A metal support made of phosphor bronze, on which are
The infrared detector (5) is fixed with a conductive adhesive (9) such as silver paste 1, so that the back electrode (7) is supported and faces the upper surface.

(10) is an alumina substrate on which an impedance conversion circuit (11) is arranged to make the infrared detector (4) low resistance because the infrared detector (5) has a high resistance, and (12) is a metal substrate. sexual cap (13) and header (1)
4), the header (14) inside the container.
) The support stand (8) and the substrate (10) are fixed to Jl. (15) is a ground terminal installed directly on the header (14), and this terminal is electrically connected to the back electrode (7) via the support base (8) and adhesive (9). has been done. (16) and (17) are the first and second lead terminals implanted via the insulating material 18 and (19) respectively on the solder (14); (20) is the surface electrode (
Lead wires (21) and (22) connect the impedance conversion circuit (11) and the first and second lead terminals (16> and 17).
) is connected with a single lead wire.

23) injects infrared rays into the infrared detector (5) from the surface electrode (6) side.
The opening (2J, (24)) is an infrared transmitting body that closes the opening 11, and the transmitting body has a thickness of several hundred am ) Made of 7-lead or germanium plate.

(25) is a shield body made of aluminum or nium and covers the infrared detector (5) and the in-heater conversion circuit (11); (26) is a shield body made of aluminum or nickel;
) There is an opening 111'C drilled in the part located on the L side.

(27) is a first facing body in the shape of a F-plane which has reached 11y on the opening [1,
A plurality of first infrared non-transparent parts (Fig. 2) extending in an i4-shaped line in a direction parallel to the paper surface (Fig. 2). 28), (2
8) and refuse the first infrared transmission
) - a first infrared transmitting part (29) located between each of
(29).

is formed. So-(,-1-2 first infrared non-transmissive part (28), (28), width W1, Wo ha approx. 1
ooッm, 1205 m, the first infrared transmitting section (29
), (29) width wl', W2 is 1] two pairs W1, W2
Same as = l i,! , is. (30) is a planar second opposing body disposed in parallel with the first opposing body (27), close to and opposite to the first opposing body; First infrared non-transmissive portion (28), (28),
A plurality of second infrared non-transmissive parts (3
1), (31), and the second infrared opaque portion (31)
), (31), and . The second infrared transmitting portions (32) and (32) are completely formed. and,
Widths w1 and w2 of the second infrared non-transmissive portions (31), (31), and the second infrared transmissive portions (32), (3
2) The widths Wl' and W2' of are respectively the widths W1 and W2 of the first infrared non-transmissive portions (28), (28), and the widths of the first infrared transmissive portions (29), (29), and wl,
It has the same dimensions as w2°.

(33) is a vibrator 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, which has a rectangular parallelepiped shape and has a length ρ. , width W and thickness a are each 30 mm, 5
mm, 0.5mmT. The second bimorph (33) is made longer in the direction perpendicular to the infrared incident direction, that is, in the lateral direction, so that the left end (33) is aligned with the header (14).
) is fixed to the insulating stand (34) provided at the right end (33
”), the L2 second opposing body (3o) is fully mounted. (3
5) The third lead terminal is embedded in the knob (14) via the insulating material (36), (37) and (38) are the fourth lead terminals.
As shown in the figure, the left end (33') of the above bimorph (33)
) with first and second vibrating electrodes formed on both sides of the first and second vibrating electrodes.
The second vibrating electrodes are connected to the third lead terminal (35) and the header (14) (earth end T-(15)), respectively. (39) is a support made of resin such as Teflon.
On the support stand. ]22 The free end (30) of the second opposing body (3o)
) is carved with a groove (4o) that slidably supports it.

Therefore, a predetermined alternating current voltage, that is, a periodic pulse, is applied to the second and second vibrating electrodes (37) via the third lead terminal (35), but no such pulses are applied. In this case, the second infrared non-transmissive portion (31), (31) of the second opposing body (3o) is the first opposing body (4:
The first infrared transmitting part' of (27)'<29), (29),
(located in the shaded area J of the third section C). When the above-mentioned pulse is applied, the pi-self (33) is bent in the A force plane, and the second infrared non-transmissive portions (31), (31) . . . become first infrared non-transmissive portion<2
8), (28), and (located at 144 in the ladle area ■ in Fig. 3C). Therefore, by periodically applying pulses to the ``-2 first vibrating electrode (37), the bimorph (33) vibrates in directions A and B in one cycle [1], and the infrared detector ( 5) has an infrared detector (4)
Infrared rays from an external object to be detected are periodically incident. When the infrared rays are incident on the infrared detector (5), the infrared rays incident on the infrared detector (5) change periodically.
5) generates a charge corresponding to this changing needle. 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 (30)).

FIG. 5 shows a circuit including the infrared detector (4),
Impedance conversion circuit in infrared detector (4) <11
) is a high resistance of 1010 to 1011Ω (41), FE
It is formed by a T (field effect transistor) (42) and an output resistor (43) of approximately 10Ω.

Then, direct 7! at the infrared detector (4) l:i first lead terminal (]6)! lEdengetsu-kasu 341 sa I[, 1st pie-e runo (33) no vibration time niha m2 Lee-+: end r
(17) C)? g! The amplitude L corresponding to the temperature difference between the temperature of the object to be detected and the room temperature! An alternating current signal υe as shown in FIG. 6a from V4 is output. (44) is a diode for room temperature that outputs the target L111"・3 in response to the room temperature where the room temperature δjll is not constant, and (45) is an astable;
1" Ab is like a periodic balloon!, oscillate r - 4 A) Oscillator, (46) is the 1. pulse r, (7) Drive circuit that outputs 1 + target pulse, (47), (,48)
, (49) i, i is a DC amplifier, (50) is a Noirtor amplifier, and (51) is a synchronous detector, which is an AC signal e from j infrared detection 'A: 4 (4) and '2. It is synchronized with the pulse r from the foot oscillator (45), and the temperature of the object to be detected is the room temperature, J, or if it is higher than that, 11 is adjusted according to the temperature difference.
- If'I/AL I+"j is output, and if the temperature of the object to be detected is lower than room temperature, a negative direct signal corresponding to the 4 degree difference is output (4a).

That is, the output flow of the infrared detector (4) ff4';'
e is 1' (
III 'I': Cycle e+ meets pulse r,
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 the synchronous detector (51)
When the pulse r and the positive half cycle e+ are matched, a positive DC signal corresponding to the temperature difference between the object to be detected and the room temperature is output, and the pulse r and the negative half cycle e- are matched. When it is removed, a negative DC signal corresponding to the temperature difference between the object to be detected and the room temperature is output.

(52) is a synthesis circuit that adds together the DC signal from the synchronous detector (51) and the DC signal corresponding to the room temperature of the room temperature diode (44), and this circuit adds the DC signal from the synchronous detector (51) to the room temperature diode (44). Outputs a signal according to body temperature. (53) is an output terminal for outputting the temperature signal to a desired circuit.

Here, the vibrational state of the bimorph (33) is such that the room temperature is 2.
5℃, and the room temperature is, for example, 30"C4m
If it is rising, the vibrational state of the bimorph (33) changes significantly compared to the above. That is, due to the rise in room temperature, the bimorph (33) is deflected by a dimension m in the B direction even when the pulse f is not generated, and the second infrared non-transmissive parts (31), (31),... The first infrared transmitting portion (29), (2) is located in the shaded area J.
9) The infrared rays from the object to be detected are not completely superimposed on the infrared rays detecting object (5). Then, if the pulse f is generated and no, the second infrared non-transmissive part <31), (31) is located in the Jj point area ■° and becomes the first infrared non-transparent part +a<28), 428), . They no longer overlap completely, and the infrared rays from the object to be detected reach the infrared detecting object (5). 1. +1. There will be no.

As a result, the amount of change in the required infrared rays of the infrared detector (5) is significantly reduced, and the output of the infrared detector (4) is as shown in Figure 6a.
As the AC signal e becomes small, it is no longer possible to obtain an AC signal e with the desired amplitude.
4) The detector Iff is significantly reduced.

(C) Embodiments The present invention has been made in view of the above points, and the embodiments of the present invention will be described in detail below based on the drawings.The same parts as those of the conventional example are designated by the same symbols. Explanation! Omitted.

In FIG. 7, (54) is the fourth lead terminal (56) implanted in the above-mentioned terminal (14) via an insulating material (55).
) is a temperature detector placed near the bimorph (33) in the housing (12) to detect the temperature of the bimorph (33) and output a direct current ()L based on the detected temperature. The diode for Heimorph has an anode connected to the fourth lead terminal (54) and a cathode connected (grounded) to the header (14).

Figure 8 shows a circuit including such an infrared detector (4゛),
(57) is a differential amplifier, one input terminal of the amplifier is connected via the anode of the morph diode (56) or the fourth lead terminal (54), and the input terminal is connected to a variable resistor. (58) is connected.

In such a resistor (58), the DC voltage input to the input terminal of the differential amplifier (57) is equal to the DC voltage input to the input terminal when the high temperature is #25°C. A desired resistance value is set in advance so that

(59> is an inverter that inverts the output of the differential amplifier (57).The output of the inverter is OV when the temperature of the bimorph (33) is 25°C; When the temperature is higher than 30℃, the temperature increase is 5℃.
A positive straight line 711EM based on C, ■BS is output as shown in FIG. 9C. (60) is an adder constituting the drive circuit (46), and in this adder, the DC voltage BS from the inverter (59) of the pulse r from the bipedal oscillator (45) is as shown in FIG. 9d. The summed output is applied to the first vibrating electrode (37).

In this case, the bimorph (33) is in a DC biased state with the direct AL voltage BS, and based on this state, it vibrates periodically in the A and B directions based on the r pulse r. Here, the bimorph (33) is deflected by a dimension m (Fig. 3 d) in the A direction in the DC bias state,
As a result, bimorph (
33) bending is eliminated. Therefore, bimorph (3
3) is the second infrared opaque part (31) as shown in Figure 3C.
, (31), are periodically located in the dot area 1 and the shaded area J, and the infrared rays incident on the infrared detector (5) are completely blocked, and the infrared rays as shown in Fig. 9a are detected from the infrared detector (4). An alternating current signal e (same as the alternating current signal e in FIG. 6a) is output.

In the above embodiment, the room temperature diode (44) and the bimorph diode (56>) are provided separately, but the detected temperature of the bimorph diode (56) is based on the temperature inside the storage body (12). Since this temperature is equal to the room temperature (temperature of the second opposing body <30), it is possible to omit the room temperature quiode (44) and have the bimorph diode (56) double as the room temperature diode (44). can. In this case, in order to more reliably detect the temperature between the bimorph (33) and the second opposing body (30), the bimorph diode (56) is connected to the bimorph (33) and the second opposing body as shown by the broken line in FIG. It is preferable to arrange it between the body (30) and the body (30). The anode of the bimorph diode (56) is connected not only to the negative input terminal of the differential amplifier (57) but also to the DC amplifier (49).

(D) Effects of the Invention As is clear from the above description, the present invention includes an infrared detector that generates a charge in accordance with the amount of change in incident infrared radiation, and an infrared transmitting section that is disposed in the infrared incident region of the detector. A pair of opposing bodies, both having an infrared transmissive part and an infrared non-transmissive part, vibrate upon application of an alternating signal]2.・Infrared 41
A state in which the transmitting part and the infrared transmitting part overlap each other and a state in which the infrared transmitting part and the non-external ray transmitting part of the pair of opposing bodies are superimposed are alternately repeated. )A
It is equipped with a temperature sensor which detects the temperature of the vibrator and outputs an iM current multiplier signal 4'' to apply a DC bias of 4'' to the vibrator based on the detected temperature. , the infrared detector can be miniaturized, and the incidence on the infrared detection object is -4
The infrared rays generated by the infrared rays can be reliably intermittent at 4' depending on the room temperature (temperature of the vibrator), and an alternating current signal with a desired amplitude can be output, thereby significantly improving the detection accuracy of the infrared detector.

[Brief explanation of drawings]

Figures 1a and b are side and plan views of a conventional infrared detection mechanism, Figure 2 is a sectional view of an improved conventional infrared detector, and Figures 3a, b, c, and d are views of people. Plan of the main part, No. 4
The figure is a diagram seen from the arrow ■ direction in Figure 2, Figure 5 is a circuit diagram including the infrared detector in Figure 2, and Figures 6 a and b are the 5
7 is a sectional view of an infrared detector according to an embodiment of the present invention, FIG. 8 is a circuit diagram including the infrared detector of FIG. 7, and FIG. 9 a, b, c, and d are 9 is a diagram of main signal waveforms in FIG. 8; FIG. (5)... Infrared detector, (12)... Storage body, (2
3)...Opening, (27)...First opposing body, (28)
, (28), . . . first infrared non-transmissive part, (29), (2
9),...First infrared transmitting portion, (30)・Second opposing body, (31), ri31),・Second infrared non-transmitting portion, (32)
, (32),...Second infrared transmitting section, (33)...Bimorph, (56)"...Diode for bimorph. ■ -m-~ Figure 4 FD 3) Core 6 Figure

Claims (1)

[Claims] (1) An infrared detector that generates a charge according to the amount of change in incident infrared rays, a pair of opposing bodies that are placed in the infrared incident area of the detector and have both an infrared transmitting part and an infrared non-transmissive part, and application of an alternating current signal. , and the infrared transmitting portion and the infrared non-transmitting portion of the one opposing body overlap with the infrared non-transmitting portion and the infrared transmitting portion of the other opposing body, respectively, and the infrared transmitting of the pair of opposing bodies. A vibrator for alternately repeating a state in which the parts and non-infrared transmitting parts are superimposed on each other, and a vibrator for detecting the temperature of the vibrator and applying a DC bias to the vibrator based on the detected temperature. An infrared detector characterized by being equipped with a temperature detector that outputs a signal.