JPH06249710A - Infrared detector - Google Patents

Abstract

PURPOSE:To provide an infrared detector suitable for mass production in which manufacturing cost is reduced while enhancing assembling performance. CONSTITUTION:The infrared detector 1 comprises a substrate 2 having a surface formed with a conductive pattern 3, a pyroelectric element 5 provided with a surface electrode 5a and a rear surface electrode, and at least two chip capacitors 6 provided with terminal electrodes 6a, 6b connected with the conductive pattern 3 on the substrate 2 and the rear surface electrode of the pyroelectric element 5 and supporting the pyroelectric element 5 while floating above the substrate 2. This structure facilitates connection between the pyroelectric element 5 and the conductive pattern 3 on the substrate 2, reduces manufacturing cost and the number of manufacturing steps, and enhances mass productivity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an infrared detector suitable as a human body detection sensor or a multi-element sensor for advanced information processing.

[0002]

2. Description of the Related Art In a pyroelectric element, a surface electrode for absorbing infrared rays is formed on the surface of a pyroelectric element made of ceramics or the like, and a back electrode for extracting a detection signal is formed on the back surface of the pyroelectric element. It will be done. When infrared rays radiated from the human body or the like are absorbed by the pyroelectric element, the pyroelectric effect raises the temperature of the pyroelectric element, changes the spontaneous polarization inside, and induces charges on the surface. Then, due to such a pyroelectric effect, a voltage and a current according to the amount of change of the incident infrared ray can be obtained.

As a conventional infrared detector, a semi-cylindrical support member made of an insulating material supports a pyroelectric element in a floating state from a substrate, and a detection signal of the pyroelectric element is provided in a space between the pyroelectric element and the substrate. It is known that circuit elements to be processed are arranged to improve the packaging density (Japanese Utility Model Publication No. 57-201938).
In addition, the pyroelectric element is supported by the conductive supporting member in a state of being floated from the substrate, and the output signal of the pyroelectric element is guided to the conductive pattern provided on the substrate through the conductive supporting member. A detector is also known (Actual Kaihei 2-14
No. 0427).

[0004]

[Problems to be Solved by the Invention]
Since the infrared detector disclosed in Japanese Patent Publication No. 57-201938 supports the pyroelectric element in a state of being floated from the substrate by using the supporting member, the circuit element exists in the space between the pyroelectric element and the substrate. However, the supporting member functions only as a supporting member, and there is a problem that the mounting density of circuit components is insufficient.

Further, since the supporting member has a semi-cylindrical shape, there is a problem that automatic mounting is difficult and assembly is poor. Furthermore, since the supporting member is made of an insulator, a conductive pattern must be applied or baked on the supporting member in order to secure a conductive path from the electrode of the pyroelectric element to the conductive pattern of the substrate. There is also a problem that it is difficult to efficiently connect the electrode of 1) and the conductive pattern of the substrate.

On the other hand, in the infrared detector disclosed in Japanese Utility Model Laid-Open No. 2-140427, since the pyroelectric element is supported by the conductive supporting member in a state of being floated from the board, other circuit parts are mounted on the board. However, there is a problem that the mounting density is insufficient. Furthermore, when a metal support member is used as the conductive support member, a number of support members corresponding to the number of output terminals of the pyroelectric element are required, which increases the number of support members and increases the manufacturing cost and the number of steps. There was also the problem of causing an increase in

Therefore, according to the present invention, the connection between the pyroelectric element and the conductive pattern of the substrate is easy, the number of steps is small, the assembly is easy, the mass production is good, and the packaging density of circuit parts is improved. It is an object of the present invention to provide an infrared detector capable of

[0008]

An infrared detector according to claim 1 is a pyroelectric device comprising a substrate having a conductive pattern formed on the surface thereof, and a front electrode and a back electrode formed on the front and back surfaces of the pyroelectric element, respectively. An element and at least two chip capacitors each of which supports the pyroelectric element in a floating state on a substrate and which has an end electrode connected to a conductive pattern of the substrate and a back electrode of the pyroelectric element. .

According to another aspect of the infrared detector of the present invention, the pyroelectric element includes at least two pairs of electrodes connected in anti-series, and the back electrode of the pyroelectric element and the conductive pattern of the substrate are the chip capacitors. The end electrodes are connected to each other.

In the infrared detector of the third aspect, other circuit parts are mounted between the chip capacitors for supporting the pyroelectric element in a floating state on the substrate.

[0011]

According to the infrared detector of the first aspect, since the infrared detector has the above-mentioned structure, the end electrodes of at least two chip capacitors interposed between the substrate and the pyroelectric element are used. The conductive pattern of the substrate and the back electrode of the pyroelectric element above the substrate can be connected, which allows the pyroelectric element and the conductive pattern of the substrate to be connected very easily, and the assemblability is improved.

Further, by using a chip capacitor having a unified standard, the manufacturing cost can be reduced and the number of steps can be reduced as compared with the conventional example, which is suitable for mass production.

According to another aspect of the infrared detector, the pyroelectric element includes at least two pairs of electrodes connected in anti-series, and the back electrode of the pyroelectric element and the conductive pattern of the substrate are the above-mentioned. Since they are connected by the respective end electrodes of the chip capacitor, it becomes easy to take out the output signal from the pyroelectric element.

According to the infrared detector of the third aspect, since other circuit parts are mounted between the chip capacitors for supporting the pyroelectric element on the substrate in a floating state,
The mounting density of this infrared detector can be improved, and further,
The overall configuration can be downsized.

[0015]

EXAMPLES Examples of the present invention will be described in detail below.

The infrared detector 1 of this embodiment shown in FIG.
A plate-shaped substrate 2 made of an insulating material having a conductive pattern 3 of a predetermined shape formed on the surface, and a front surface electrode (light receiving electrode) 5a and a back surface electrode are formed on both front and back surfaces of the plate-shaped pyroelectric element 4, respectively. The pyroelectric element 5 and the conductive pattern 3 on the substrate 2 are arranged at a predetermined interval to support the pyroelectric element 5 above the substrate 2 in a floating state, and the conductive pattern 3 on the substrate 2 and the pyroelectric element 3 are supported. End electrodes 6a and 6b respectively connected to the back surface electrodes of the element 5
And two chip capacitors 6 provided with a circuit component (for example, an FET, a transistor, an operational amplifier, a resistor) arranged in a space between the two chip capacitors 6 and connected to the conductive pattern 3 by a lead terminal 8. , A condenser, etc.) 11 and a filter 9 having a predetermined light transmittance at a position corresponding to the pyroelectric element 5, and the two filters are placed directly above the pyroelectric element 5. A chip body 6 for sealing the chip capacitor 6 and the pyroelectric element 5 from the outside is provided.

FIG. 2 shows the infrared detector 1 in the state of being covered with the cover 10.

The pyroelectric element 5 is made of, for example, an organic crystal such as TGS (triglycine sulfate), an inorganic crystal such as LiTaO ₃ (lithium tantalate), or a ceramic such as PbTiO ₃ (lead titanate). A plurality of surface electrodes 5a are formed on the surface of the pyroelectric element 4, the light receiving elements C1 and C2 are connected in an anti-series state as shown equivalently in FIG. 3, and an output signal is output via the field effect transistor FET. To take out. Furthermore, the pyroelectric body 4
A plurality of back surface electrodes (not shown) are formed on the back surface of the so as to face the respective front surface electrodes 5a to form a multi-channel structure.

The back electrode of the pyroelectric element 5 and the end electrodes 6a and 6b of the chip capacitor 6 are electrically connected by a conductive adhesive or the like. The conductive pattern 3 on the substrate 2 and the end electrodes 6a and 6b of the chip capacitor 6 are electrically connected by soldering, a conductive adhesive or the like.

FIG. 4 shows the light receiving elements C1 and C2.
2 shows an equivalent circuit when two sets of field effect transistor FETs are provided.

According to the infrared detector 1 having the above structure,
At least 2 interposed between the substrate 2 and the pyroelectric element 5.
Using the respective end electrodes 6a, 6b of the individual chip capacitors 6, the conductive pattern 3 of the substrate 2 and the back surface electrode of the pyroelectric element 5 above the substrate 2 can be electrically simply made by a conductive adhesive or the like. The infrared detector 1 can be connected, and the assemblability of the infrared detector 1 is improved.

Further, by using the chip capacitor 6 having the unified standard, the manufacturing cost can be reduced, the number of steps can be reduced as compared with the conventional example, and the mass productivity can be improved.

Further, since another circuit component 11 can be mounted between the chip capacitors 6 for supporting the pyroelectric element 5 on the substrate 2 in a floating state, the two chip capacitors 6 and The circuit components 11 and can be mounted at a high density, and the mounting density of the infrared detector 1 can be improved.
The overall configuration can be downsized.

Furthermore, the pyroelectric element 5 has at least 2
A pair of anti-series connected front electrodes 5a are provided, and the back electrode of the pyroelectric element 5 and the conductive pattern 3 of the substrate 2 are connected by the respective end electrodes 6a and 6b of the chip capacitor 6. Therefore, it becomes easy to take out the output signal from the pyroelectric element 5.

Next, a second embodiment of the present invention will be described with reference to FIG.

The infrared detector 1A shown in the figure has a structure similar to that of the infrared detector 1, except that the pyroelectric element 15 is
At least two electrode pairs 1 connected in anti-series on the surface
5a and 15b, and the electrode pair 15 of this pyroelectric element 15
a and 15b, the back surface electrodes and the conductive pattern 3 of the substrate 2 are connected to the end electrodes 6a of the chip capacitors 6,
6b are electrically connected to each other, two circuit components 20a and 20b are mounted in the spaces between the chip capacitors 6, and the lead terminals 21a and 21b are used to connect to the conductive pattern 3. .

With the infrared detector 1A having such a structure, it is possible to exhibit the same operational effect as that of the infrared detector 1.

The present invention is not limited to the above embodiment, but can be modified in various ways.

For example, in the above-mentioned embodiment, 2 on the substrate.
I explained the case of mounting the chip capacitors at intervals, but the number of chip capacitors mounted is 3,
It can be implemented as an arbitrary number such as four.

[0030]

According to the present invention described in detail above, the following effects can be obtained.

According to the first aspect of the present invention, since the above-mentioned structure is adopted, the connection between the pyroelectric element and the conductive pattern of the substrate can be facilitated, and the manufacturing cost can be reduced. It is possible to provide an infrared detector that can be reduced in mass production and is excellent in mass productivity.

According to the second aspect of the invention, it is possible to provide an infrared detector in which the output signal from the pyroelectric element can be easily taken out.

According to the third aspect of the present invention, it is possible to provide an infrared detector capable of improving the packaging density of circuit components and further downsizing the entire structure.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of an infrared detector of the present invention with a part cut away.

FIG. 2 is a perspective view showing the appearance of the infrared detector of this embodiment.

FIG. 3 is an equivalent circuit diagram of the infrared detector of this embodiment.

FIG. 4 is an equivalent circuit diagram of another example of the infrared detector of this embodiment.

FIG. 5 is a perspective view showing another embodiment of the infrared detector of the present invention with a part cut away.

[Explanation of symbols]

 1 Infrared Detector 2 Substrate 3 Conductive Pattern 4 Pyroelectric Element 5 Pyroelectric Element 5a Surface Electrode 6 Chip Capacitor 6a, 6b End Electrode 11 Circuit Parts

Claims (3)

[Claims] 1. A substrate having a conductive pattern formed on its surface, a pyroelectric element having a front electrode and a back electrode formed on both front and back surfaces of a pyroelectric element, and the pyroelectric element suspended above the substrate. An infrared detector comprising: at least two chip capacitors that support and are provided with a conductive pattern of the substrate and an end electrode connected to a back electrode of a pyroelectric element. 2. The pyroelectric element includes at least two pairs of electrodes connected in anti-series, and a back electrode of the pyroelectric element and a conductive pattern of a substrate are connected by each end electrode of the chip capacitor. The infrared detector according to claim 1, which is a 3. The infrared detector according to claim 1, wherein another circuit component is mounted between the chip capacitors that support the pyroelectric element in a floating state on the substrate.