JPH0313707Y2 - - Google Patents

Description

[Detailed Description of the Invention] (a) Field of Industrial Application The present invention relates to an infrared sensor for detecting the temperature of a detected part using infrared rays, for example.

(b) Prior Art In FIGS. 1a and 1b, a recent infrared sensor 1 has a built-in infrared detector, for example, of a pyroelectric type. Such an infrared detector has a characteristic of generating electric charge based on the amount of change in the amount of incident infrared rays, and the detection accuracy of the infrared detector improves as the amount of incident infrared rays changes more periodically. It is necessary to periodically change the infrared rays incident on the object to be detected, and for this purpose, a metal chopper 3 that is driven to rotate periodically by a synchronous motor 2 is arranged in front of the infrared sensor 1. Therefore, when the infrared rays from the detected part and the infrared rays from the chopper 3 are alternately and periodically incident on the infrared detecting body by such rotation of the chopper 3, the amount of incident infrared rays becomes periodically incident on the infrared detecting body. and generates an electric charge. Such charges are used to measure the temperature of the detected part.

However, in the above configuration, the motor 2 and the chopper 3 have a considerably large shape, and there are problems in terms of space.

Therefore, an infrared sensor 4 as shown in FIGS. 2 and 3 has been devised. Such an infrared sensor 4
The length, width, and height of the external dimensions are approximately
It has a small rectangular parallelepiped shape with dimensions of 60, 20, and 15 mm, and has a built-in novel chopper mechanism, thus eliminating the need for the motor 2 and chopper 3 as described above, and solving the space problem.

The specific structure of the infrared sensor 4 will be explained below.

Inside a sensor case 8 consisting of a metal header 5 and a cap 7 having an infrared transmitting section 6,
a pyroelectric infrared detector 10 that is surrounded by a shield body 9 and generates an electric charge based on the amount of change in incident infrared rays;
A chopper mechanism is provided to change the infrared rays incident on the detection object. The tippa mechanism is
A pair of piezoelectric vibrating bodies 11, 12 and a pair of opposing bodies 13, 14 fixed to the free ends of each of the vibrating bodies
It is made up of A plurality of slits 15, 15, . . . of the same shape and size are formed in the opposing bodies 13, 14, respectively, to allow infrared rays to pass therethrough.

The vibrating bodies 11 and 12 periodically vibrate in directions opposite to each other (direction A or B), and as a result, the relative positional relationship of the opposing bodies 13 and 14 changes periodically. A state in which the slits 15, 15, . . . of each of the slits 13, 14 are overlapped and opened, and a state in which the slits 15, 15, . . . are not overlapped and closed, are periodically repeated. Then, in the superimposed state, the infrared rays from the detected part are transmitted to the infrared transmitting part 6 of the case 8 and both opposing bodies 13 and 1.
4 and enters the infrared detector 10 through the slits 15, 15, .
0, the amount of incident infrared rays changes periodically and generates a charge for measuring the temperature of the detected part, for example.

Now, in the infrared sensor 4, the opposing bodies 13, 14 are non-perpendicular to the vibration direction (A, B direction) of the vibrating bodies 11, 12.
2, that is, the upper surfaces 11' and 12', with an adhesive.

However, the upper surfaces 11' of the vibrating bodies 11 and 12,
12' is made narrow so that a sufficient amount of adhesive cannot be applied, and therefore, in the case of the sensor 4, sufficient adhesive strength cannot be obtained to reliably adhesively fix the opposing bodies 13 and 14. Nakatsuta.

(c) Purpose of the invention The purpose of the present invention is to obtain an infrared sensor that can securely bond and fix the opposing body to the vibrating body with sufficient adhesive strength.

(d) Structure of the present invention In order to achieve the above object, the structure of the present invention includes an infrared detector that generates an electric charge according to the amount of change in incident infrared rays, and a plurality of infrared passing parts and infrared non-passing parts. A pair of opposing bodies located in the infrared incident area of the infrared detector, and a vibrating body that vibrates at least one of the opposing bodies to periodically change the opening/closing degree of the infrared passing portion of the pair of opposing bodies. In the infrared sensor, the vibrating body is composed of a central electrode having a notch, piezoelectric bodies placed on both sides of the central electrode, and surface electrodes placed on each outer side of the piezoelectric body. In addition, a recess surrounded by the notch of the central electrode and the piezoelectric body is formed on a non-vertical surface that is not perpendicular to the vibration direction, and the opposing body is formed on the non-vertical surface, and an adhesive collected in the recess is formed on the non-vertical surface. It is characterized by being fixed with adhesive.

(e) Embodiment FIGS. 4 to 14 show an infrared sensor 16 according to an embodiment of the present invention. The external dimensions of the sensor are length,
The width and height are 24, 16, and 15 mm, respectively, and the sensor 16
has been sufficiently miniaturized.

First, the sensor case 17 is made of metal cap 1.
8 and a header 19. The cap 18 is closed with an infrared-transmissive silicon plate 20 and is formed with an external infrared ray entrance opening 21 having a diameter of 3.5 mm for guiding external infrared rays emitted by the object to be detected into the case 17. Further, the first to fifth terminals 22a to 22e are implanted in the header 19 via an insulator, and the sixth terminal 22f is directly implanted. Furthermore, the seventh and eighth dummy
Terminals 22g and 22h are implanted.

Therefore, the header 19 is installed inside the case 17.
An alumina main substrate 23 is bonded thereon with an epoxy-based insulating adhesive 24. in this case,
The main board 23 has the first to eighth terminal holes 25a to 25.
h, and the first to eighth terminals 22a to 22h are fitted into these terminal holes 25a to 25h, respectively. Further, first to seventh electrodes 26a to 26g are patterned on the upper surface of the main substrate 23 by screen printing and sintering silver palladium. The first to sixth terminals 22a to 22f are soldered to these first to sixth electrodes 26a to 26f, respectively. The seventh and eighth terminals 22g and 22h are further soldered connected to the sixth electrode 26f.

Then, the main board 23 is placed inside the case 17.
On the top, there is an infrared detection section 27 and a chopper mechanism section 28.
etc. are configured in a hybrid manner, making it more compact.

First, the infrared detecting section 27 will be described. It has front and back electrodes 29 and 30, and is made of a pyroelectric lithium tantalate LiTaO ₃ single crystal of approximately 1.5 mm square that generates electric charge based on the amount of change in incident infrared rays. A type infrared detector 31 is provided, and the detector is adhesively fixed onto a metal support 32 made of phosphor bronze with a conductive adhesive 33 such as silver base. and,
The support base 32 is also attached to the wide portion 26 of the sixth electrode 26f using a conductive adhesive 34 such as silver base.
f', thereby attaching the adhesives 33, 34 to the back electrode 30, the support base 32, and the sixth electrode 26f.
The surface electrode 29 is electrically connected to the sixth terminal 22f via the seventh electrode 26.
It is electrically connected to g.

Further, along with the infrared detector 31, a resistor chip 35 and an FET 36 are provided. Such a resistor chip 35 is particularly constructed as shown in FIG. 11, in which an alumina piece 37 is used, and by screen printing silver palladium on both ends of one side of the piece and sintering it, a pair of resistor electrodes 38a, 38b is formed, and a resistance of 10 ¹⁰ to 10 ¹¹ Ω is formed across the electrodes.
A resistive layer 39 is formed by screen printing.
The resistance chip 35 has both resistance electrodes 38
a and 38b are fixed on the main substrate 23 by adhering them to the sixth and seventh electrodes 26f and 26g using cream solder. Furthermore, the above FET3
6, connect the source S, drain D, and gate G to the first, second, and seventh electrodes 2 using the same cream solder.
It is fixed on the substrate 23 by adhering to 6a, 26b, and 26g.

The infrared detector 31, resistor chip 35, and FET 36 are covered with a metal shield 40 made of phosphor bronze or tin and whose inner surface is coated with black fade paint. The shield body has a triangular roof shape and includes lower pieces 40a, 40a and claws 40.
b, 40b. Thus, the lower pieces 40a, 40a of the shield body 40 are connected to the main board 23.
The claws 40b, 4 engage with the long sides 23a, 23a of the
0b is a notch 23b formed in the main board 23
The shield body 40 is soldered to the sixth electrode 26f while being engaged with the engagement hole 23c, thereby fixing the shield body 40 on the main board 23. An infrared passing hole 41 with a diameter of about 1.8 mm is formed on the upper surface of the shield body 40, just above the infrared detecting body 31.

Next, to explain the chopper mechanism section 28, an alumina fixing plate 42 is provided. The fixing plate has notches 44a, 4 formed at the corners of the main board 23, with engaging pieces 43a, 43b at both ends of the lower part.
4b, and is vertically adhesively fixed to the main substrate 23 with an epoxy-based insulating adhesive 45. In addition, a pair of notches 46a, 46 with a length of 4 mm and a width of 0.5 mm are provided on the upper part of the fixing plate 42, for example.
b are formed at an interval of 5 mm from each other, and two electrodes 47a and 47b are patterned on one side of the fixed plate 42 by screen printing and sintering silver palladium in the same manner as the main substrate 23. has been done. This electrode 47b has the above-mentioned notch 4
The electrode 47a has a pattern surrounding the notches 6a and 46b, and the electrode 47a has a pattern located between the notches 46a and 46b.
a and 47b are the third and fourth parts on the main board 23, respectively.
It is soldered connected to electrodes 26c and 26d.

A pair of vibrating bodies 48, 49 having lengths, heights, and thicknesses of, for example, 18, 4, and 0.5 mm, respectively, are arranged in the notches 46a, 46b so as to be perpendicular to the fixing plate 42. The vibrating bodies 48 and 49 are fixed with an epoxy-based insulating adhesive. In the vibrating bodies 48 and 49, as shown in detail in FIGS. 6 and 10, there are central electrodes 50a and 50b made of phosphor bronze, etc., and piezoelectric bodies 51a and 50b are provided on both sides of each central electrode. 51b and 52
a, 52b are provided, and these piezoelectric bodies 51a, 5
Surface electrodes 53a, 53b and 54a, 54 made of silver or the like are provided on the outer surfaces of 1b, 52a, 52b.
b is formed. The piezoelectric bodies 51a, 51b
and 52a, 52b are polarized in the same direction for each of the vibrating bodies 48, 49 and in opposite directions between the vibrating bodies 48, 49 (polarization direction P in FIG. 6).
Then, the surface electrodes 53a, 53b and 54
a and 54b are both electrodes 47 of the fixed plate 42.
b with cream solder, and the central electrode 50
a, 50b have branch pieces 55a, 55b extending from the ends of the vibrating bodies 48, 49. The branch piece is bent toward the electrode 47a side of the fixing plate 42 and connected to the electrode 47a with cream solder.

Thus, on the free end sides of the vibrating bodies 48, 49, non-perpendicular surfaces of the vibrating bodies 48, 49 that are non-perpendicular to the vibration direction of the vibrating bodies 48, 49, that is, upper surfaces 48', 4
9', a pair of opposing bodies 56, 57 which face the external infrared ray entrance 21 closely with an interval of about 1.1 mm.
Sumikittu so that they are parallel to each other.
They are adhesively fixed using an acrylic insulating adhesive 56', 57' such as SG210M (trade name of Sumitomo Chemical Co., Ltd.). In this case, the opposing bodies 56, 57 have adhesive pieces 56a, 57a with a width w of about 2 mm, while the adhesive parts of the upper surfaces 48', 49' have:
The center electrodes 50a, 50b are cut out and have a recess 58
a, 58b are formed. Such a recess 58a,
In 58b, the length l is 10 to 200% of the width w.
0.2 to 4 mm is appropriate, and more specifically, 2.7 mm is preferable. Further, the depth d is suitably 0.05 to 1 mm, more preferably 0.17 mm. Then, the adhesives 56', 57' accumulate in the recesses 58a, 58b, and a large amount of adhesives 56', 57' are present between the opposing bodies 56, 57 and the vibrating bodies 48, 49. Therefore, the adhesion and fixing strength of the opposing bodies 56 and 57 is sufficient.

Next, the opposing bodies 56 and 57 are made of an infrared opaque material such as aluminum, and are shown in FIG.
As shown in detail in FIG. 1B, infrared passing portions 59 and 60 are formed as a plurality of slits extending in a fan-shaped line, and infrared non-passing portions 61 and 62 are located between each of the passing portions. ing. Both of these passing portions 59, 60 and non-passing portions 61, 62 have the same size and shape.

On the main board 23 in the case 17, the infrared detector 27 and the chopper mechanism section 2 are provided.
In addition to 8, a temperature measuring diode 65 for measuring the temperature inside the case 17, which is equal to the temperature of the opposing bodies 56 and 57, is incorporated. The diode 65 is placed in an upright state, and its anode and cathode are connected to the fifth and sixth electrodes 26e and 26e on the main substrate 23, respectively.
It is soldered connected to 26f.

Next, the specific operation of the sensor 16 will be explained.

The vibrating bodies 48 and 49 vibrate based on the voltages applied to the third and fourth terminals 22c and 22d. That is, a DC constant voltage of about +5 volts is applied to the fourth terminal 22d, while the third terminal 22d
Voltages of approximately +35 and -25 volts are applied alternately and periodically (frequency 3 to 5 Hz) to c. Then, the fixing plate 4 is attached to the third and fourth terminals 22c and 22d.
Center electrodes 50a, 50b of the vibrating bodies 48, 49 connected via electrodes 47a, 47b on 2
and surface electrodes 53a, 53b and 54a, 54b
Regarding the state where the center electrodes 50a, 50b are 30 volts higher than the surface electrodes 53a, 53b and 54a, 54b (hereinafter referred to as the H state) and 30
The state in which the voltage is lowered by only the volt (hereinafter referred to as the L state) is alternately repeated at a frequency of 3 to 5 Hz as shown in FIG. In the case of the H state, the piezoelectric bodies 51a and 52a of the vibrating bodies 48 and 49 contract, and the piezoelectric bodies 51b and 52b expand, so that both vibrating bodies 4
8 and 49 are bent in the S and S' directions (Fig. 6), respectively. On the other hand, in the case of the L state, both vibrators 48 and 49 are bent in the S'S direction, contrary to the above. As a result, the vibrating bodies 48 and 49 periodically vibrate in opposite directions.

Based on such vibration, the opposing body 5
6 and 57 are displaced in relative position, and both opposing bodies 5
A state in which the infrared passing portions 59 and 60 of 6 and 57 are almost overlapped and open (corresponding to the above H state)
, and a state in which they are occluded with almost no overlap (corresponding to the L state) are periodically repeated. In this case, the opposing bodies 56 and 57 are the infrared detectors 3
As a result, the infrared detector 31 detects the infrared rays from the object passing through the external infrared entrance 21 and entering the sensor case 17 and the infrared rays from the opposing bodies 56 and 57. The amount of incident infrared rays changes periodically based on the infrared rays, and therefore a signal corresponding to the electric charge corresponding to the temperature of the object to be detected, more specifically, the temperature difference between the object to be detected and the opposing bodies 56 and 57 is output. do.

A signal corresponding to the temperature of the opposing bodies 56, 57 from the temperature measuring diode 65 is then added to this signal outside the sensor 16, thereby obtaining an accurate temperature signal for the object to be detected.

(f) Effects of the invention According to the invention, an infrared detection body that generates electric charges according to the amount of change in incident infrared radiation, and a plurality of infrared transmission parts and an infrared transmission part located in the infrared incidence area of the infrared detection body. an infrared sensor comprising a pair of opposing bodies, and a vibrating body that vibrates at least one of the opposing bodies to periodically change the opening/closing degree of the infrared passing portion of the pair of opposing bodies,
The opposing body vibrated by the vibrating body is
Since the vibrating body is adhesively fixed to the non-vertical surface of the vibrating body that is not perpendicular to the vibration direction of the vibrating body using the adhesive stored in the recess formed in the non-vertical surface, the adhesive strength of the opposing body can be sufficiently increased. Therefore, the adhesive fixation described above can be performed reliably.

Further, the vibrating body is composed of a central electrode having a notch, piezoelectric bodies placed on both sides of the central electrode, and surface electrodes placed on each outer side of the piezoelectric body. A concave portion surrounded by the notch portion of the central electrode and the piezoelectric body is formed on a non-vertical surface of the vibrating body. Since the recess is thus formed by cutting out the center electrode, it can be easily formed on the non-recessed surface of the vibrating body.

[Brief explanation of the drawing]

FIGS. 1a and 1b are a side view and a plan view of a conventional infrared detection mechanism, FIGS. 2 and 3 are a sectional view and a plan view of essential parts of an improved conventional infrared sensor, respectively, and FIGS. 12 shows the structure of an infrared sensor according to an embodiment of the present invention, FIG. 4 is an exploded perspective view, FIG. 5 is a cross-sectional view seen from the side, FIG. 6 is a cross-sectional view along the - line in FIG. 5, and FIG. In Figure 5 -
8 is a sectional view taken along the - line in FIG. 5, FIG. 9 is a plan view of the main board, FIG. 10 is a perspective view of main parts, FIG.
Figures a and b are plan views of the opposing bodies, Figure 13 is a circuit diagram of the infrared sensor of the above embodiment, and Figure 14 is the first infrared sensor.
FIG. 4 is a diagram of main part signal waveforms in FIG. 3; 17...Sensor case, 18...Cap, 1
9... Header, 21... External infrared incidence port, 31
...Infrared detection body, 40...Shield body, 42...
... Fixed plate, 48, 49... Vibrating body, 56, 57...
... Opposing body, 58a, 58b... Recess, 59, 60
... Infrared passing section, 61, 62... Infrared non-passing section.

Claims (1)

[Scope of utility model registration request] an infrared detector that generates a charge according to the amount of change in incident infrared rays; a pair of opposing bodies having a plurality of infrared passing parts and infrared non-passing parts and located in an incident area of the infrared detecting body; and the pair of opposing bodies. an infrared sensor comprising a vibrating body that vibrates at least one of the opposing bodies in order to periodically change the opening/closing degree of an infrared passing section, the vibrating body having a central electrode having a notch portion, and a vibrating body that vibrates at least one of the opposing bodies in order to periodically change the degree of opening/closing of an infrared passing section; It is composed of piezoelectric bodies arranged on each surface, and surface electrodes arranged on the outer surface of each piezoelectric body, and a recessed part surrounded by the cutout part of the center electrode and the piezoelectric body is arranged in the vibration direction. An infrared sensor formed on a non-vertical surface, and characterized in that the opposing body is adhesively fixed to the non-vertical surface with an adhesive stored in the recess.