JP2606637Y2 - Infrared array sensor - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an infrared array sensor for detecting an infrared heat source such as a human body.

[0002]

2. Description of the Related Art FIG. 6 (b) shows a main configuration of a conventional infrared array sensor. In the figure, a pyroelectric substrate 8 is mounted on a circuit board 5, and the circuit board 5
A plurality of solder bumps 4 formed thereon and a pyroelectric substrate 8
Are electrically connected to each other by the conductive paste 18. Also, on the front side of the pyroelectric substrate 8,
A plurality of ground electrodes 9 are formed.

As shown in FIG. 7A, a plurality of (4 × 4 = 16) two-dimensional arrays are formed on one surface (front surface) of the pyroelectric substrate 8. ) Are arranged in a conductive state with each other by the conductor pattern 3, and a plurality of (4 × 4 = 16) electrodes are arranged in a two-dimensional array on the back side as shown in FIG. ) Electrode 2 is ground electrode 9
The pyroelectric element 1 having a plurality of (16) pixels is arranged and arranged at a position opposed to.

As shown in FIGS. 6A and 7, a conductive adhesive for commonly connecting the ground electrode 9 to an external ground potential is provided on the ground electrode forming surface 15 of the pyroelectric substrate 8. One connecting portion 11 is formed using a conductive paste. The connection portion 11 of this one conductive adhesive
Is electrically connected to a ground potential electrode 6 provided on the circuit board 5 by a conductive adhesive 10 as shown in FIG. As a base material of the conductive adhesive 10, an epoxy-based resin, a phenol-based resin, or a silicon-based resin is used.

FIG. 3 is a perspective view of each component constituting the infrared array sensor. To incorporate and manufacture an infrared array sensor using each of these components, first,
A pyroelectric element 1 on the surface of the circuit board 5, a plurality of FET (field effect transistor) and a plurality of resistors R _g is connected,
A plurality of FETs and a plurality of R _g are also connected to the back surface of the circuit board 5. The fitting holes 17 of the circuit board 5 to which these components are connected
Then, the shaft 16 of the stem 7 is inserted, and the circuit board 5 is mounted on the stem 7. On the other hand, a silicone filter 14 is fitted into the window 13 of the can case 12, the can case 12 is put on the stem 7, the circuit board 5 in which the components are incorporated and connected is accommodated in the can case 12, and hermetically sealed by a hermetic seal to be used. Make an array sensor.

FIG. 5 shows a circuit configuration of the infrared array sensor. The infrared array sensor, the resistance R _g each pixel of the pyroelectric element 1 are connected in parallel, the ground electrode 9 one <br/> end side of the pixel is connected to the ground potential, infrared other end of the pixel The electrode 2 functioning as a detection signal output electrode is connected to the gate of the FET, and a circuit is formed for each pixel. The infrared to the infrared array sensor from the heat source is incident, polarized by each pixel of the pyroelectric element, a current flows from the pixels, converted into a voltage by the resistor R _g, impedance converted by the signal is output by the FET, The heat source is detected based on the signal.

[0007]

However, the conventional infrared array sensor uses the surface of the pyroelectric substrate 8 on which the ground electrode is formed.
15, a connection portion 11 of a conductive adhesive for commonly connecting the ground electrode 9 to an external ground potential is provided at one place, and the connection portion 11 of the conductive adhesive at one place and the ground potential electrode 6 are connected to each other. Due to the configuration of conducting connection by the conductive adhesive 10,
When a temperature change is applied to the connection portion 11 of the conductive adhesive of the infrared array sensor from the outside, the conductive adhesive 10 expands and contracts. However, as shown in FIG.
Because the conductive adhesive 10 expands and contracts on the pyroelectric substrate 8, the solder bump 4A closest to the connection portion 11 of the conductive adhesive is used as a fulcrum and the arrow F Large stress is generated in the direction, and chipping, cracking, peeling, and the like are likely to occur at the connection portion of the solder bump 4 of each pixel, and there is a problem that the reliability of the infrared array sensor is impaired.

[0008] Also, depending on the occurrence of cracks, chips or peeling at the connection portions of the solder bumps 4 of each pixel, the pyroelectric substrate 8
In this case, the conduction state of the circuit board 5 is deteriorated, causing an increase in noise and a problem of poor sensitivity.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a highly reliable infrared array sensor at a solder bump connecting portion between a pyroelectric substrate and a circuit substrate. is there.

[0010]

The present invention is configured as follows to achieve the above object. In other words, the
In the infrared array sensor according to the first aspect, the front and back sides of the pyroelectric substrate are used as ground electrode forming surfaces, and a plurality of ground electrodes are arranged in a two-dimensional array on the ground electrode forming surface in a conductive state. The pyroelectric substrate is provided with a plurality of
Number of infrared detection signal output electrodes face the ground electrode
And a connection portion of a conductive adhesive for commonly connecting the ground electrode to a ground potential electrode on the circuit board side is formed on the ground electrode forming surface of the pyroelectric substrate .
The infrared detection signal output electrodes are arranged on the circuit board surface.
Connected to the formed solder bumps and provided on the circuit board.
In the infrared array sensor which is electrically connected to the gate of the FET that is, the connecting portion of the conductive adhesive before and after at least the ground electrode formation surface of the pyroelectric substrate, left, and either symmetrical positions diagonal It is formed on the outer peripheral edge of the ground electrode forming surface . Also, the second
According to the first aspect of the present invention, a pyroelectric substrate is provided.
Is a square substrate, and the connection part of the conductive adhesive is square
At the four corners of the ground electrode forming surface
It is characterized by having been done.

[0011]

A plurality of ground electrodes are formed in a two-dimensional array on a pyroelectric substrate, and a plurality of conductive adhesives are connected to any of the front, rear, left, right, and diagonal symmetrical positions of the ground electrode formation surface. Form a part. When a change in heat from the outside is transmitted to the connection portion of the conductive adhesive, the conductive adhesive expands and contracts. By the agent, the bias of the stress applied to each pixel as a pyroelectric body is reduced and averaged. As a result, the stress applied to the solder bump connection portion of each pixel is reduced, cracks, chips, peeling, and the like are eliminated, and an accurate detection of a heat source can be performed without an increase in noise or poor sensitivity.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. In the description of the present embodiment, the same reference numerals are given to the same names as those in the conventional example, and detailed description thereof will be omitted. FIG. 1 shows a main configuration of a pyroelectric substrate of the infrared array sensor according to the present embodiment.

The infrared array sensor of this embodiment detects an infrared heat source such as a human body in the same manner as the conventional example, and includes a plurality of ground electrodes 9 arranged in a two-dimensional array on a pyroelectric substrate 8. When the common connection to the ground potential electrode 6 of the circuit board 5 is performed, a conductive adhesive 10 such as a conductive paste is applied to the connection portion 11 of the conductive adhesive, and the ground potential electrode 6 and the ground electrode 9 are connected in common. Is what you do.

A feature of this embodiment is that the connection portion 11 of the conductive adhesive is placed at least in any symmetrical position of the ground electrode forming surface 15 of the pyroelectric substrate 8 in any of the front, rear, left, right, and diagonal directions. That is, a plurality is formed.

FIG. 1 shows each pyroelectric element of the infrared array sensor of this embodiment. Each pyroelectric element 1 of the present embodiment
In the same manner as in the conventional example, a plurality of (4 × 4 = 4 × 4 = 4 ) pixels are formed on the ground electrode forming surface 15 of the rectangular pyroelectric substrate 8 in a two-dimensional array.
The pyroelectric element 1 has 16 pixels on which (16) ground electrodes 9 are formed. In the pyroelectric element 1 of this embodiment, the ground electrode 9 is commonly connected to the ground potential of the circuit board 5 as in the conventional example, and the description of the conductive connection on the circuit board side is omitted for convenience of explanation.

The pyroelectric element 1 shown in FIG. 1A is located at symmetrical positions before and after the ground electrode forming surface 15 of the pyroelectric substrate 8.
One at each, a total of two conductive adhesive connections 11
The conductive adhesive 10 is applied to the connecting portion 11 of the conductive adhesive to connect the ground potential of the circuit board 5 and the plurality of ground electrodes 9 in common. FIG. 1 (b)
The connection portions 11 of the conductive adhesive are formed at two locations, one at each, at diagonally symmetrical positions on the ground electrode forming surface 15 of the pyroelectric substrate 8. Further, FIG. 1 (c) shows four conductive adhesive connecting portions 11 at one location each at a symmetric position in the front-rear direction of the ground electrode forming surface 15 and a left-right symmetric position orthogonal to the front-rear direction. FIG. 1 (d) shows the connection points 11 of the conductive adhesive at a total of four locations, one at each of the four diagonal symmetrical positions of the four corners of the rectangular ground electrode formation surface 15. It was formed.

According to the present embodiment, the connecting portion 11 of the conductive adhesive is formed at any symmetric position of the front, rear, left, right and diagonal of the ground electrode forming surface 15 of the pyroelectric substrate 8, and this connection is performed. Since the conductive adhesive 10 is applied to the portion 11, the conductive adhesive 10 expands and contracts when a heat change from the outside is applied to the conductive adhesive 10, but the conductive adhesive 10 Expansion, contraction, the stress applied to the bump connection portion of each pixel by the conductive adhesive 10 of the symmetric position, and,
The bias of the stress is alleviated, and the crack, chipping, peeling, and the like of the connection portion of the solder bump 4 of each pixel are eliminated unlike the related art, so that the reliability of the infrared array sensor can be improved.

Further, stress due to expansion and contraction of the conductive adhesive 10 is applied evenly to the solder bump connection portion of each pixel, the magnitude of the stress applied to the bump connection portion of each pixel decreases, and the stress of the stress decreases. Since variations are reduced, cracks, chips or peeling of solder bump connection parts are eliminated, and the conduction state between the pyroelectric substrate and the circuit board can be secured stably, which may increase noise and cause poor sensitivity. Absent.

The present invention is not limited to the above embodiment, but can take various embodiments. For example, in the above-described embodiment, one place, a total of two places or front and rear, respectively, in front and rear and diagonally symmetric positions of the ground electrode forming surface 15 of the pyroelectric substrate 8,
The connecting portions 11 of the conductive adhesive were formed at a total of four locations, one at each of the left, right, and diagonal symmetrical positions. As shown in FIG. As in the case of forming the connection portion 11 of the conductive adhesive, the number of the connection portions 11 of the conductive adhesive formed in symmetrical positions may be plural,
The number is not limited. In this case, the bias of the stress applied to each pixel is further averaged, and the connection reliability of the solder bump connection portion is further improved.

In the above embodiment, the number of pixels of the pyroelectric element 1 is 4 × 4 = 16 in a two-dimensional array on the pyroelectric substrate. Or 5 × 5 = 25 in a two-dimensional array,
The number of pixels does not matter.

Further, in the above embodiment, the conductive adhesive 10
As the base material, an epoxy-based resin, a phenol-based resin, a silicon-based resin, or the like was used. However, for example, an acrylic resin may be used, and any material may be used as long as the conductive adhesive 10 is formed.

[0022]

According to the present invention, the symmetric position of any of the front, rear, left, right, and diagonal of the ground electrode forming surface of the pyroelectric substrate is obtained.
Connect the ground electrode on the circuit board side to the outer peripheral edge of the ground electrode formation surface .
Since a plurality of connecting portions of the conductive adhesive connected to the land potential electrode are formed, when a heat change from the outside is transmitted to the connecting portion, the conductive adhesive at the connecting portion expands and contracts.
To apply stress to the pyroelectric substrate.
The vertical stress ( soldering bump) is applied to the pyroelectric substrate applied to the external line detection signal output electrode and the solder bump connection on the circuit board side.
The size of the direction stress) for peeling pulled apart the connection between the flop is reduced, and the variation of the stress is relieved, as in the prior art, cracks or the bump connection portions each'm,
Since the occurrence of chipping or peeling can be prevented, the reliability of the infrared array sensor can be improved.

Further, the expansion of the conductive adhesive, the stress due to shrinkage, each joined evenly to the bump connection portion I, and the stress is reduced and cracking and chipping and peeling off or the like of the solder bump connection portion Therefore, the conduction state between the pyroelectric substrate and the circuit board can be stably ensured, so that it is possible to prevent an increase in noise and the occurrence of poor sensitivity.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a main configuration of an infrared array sensor according to the present embodiment.

FIG. 2 is an explanatory diagram of a pyroelectric element having another configuration of the present embodiment.

FIG. 3 is an exploded perspective view of the infrared array sensor.

FIG. 4 is an explanatory diagram showing a state in which stress and strain are applied to a circuit board and a pyroelectric substrate of a conventional infrared array sensor.

FIG. 5 is an explanatory diagram of a circuit of the infrared array sensor.

FIG. 6 is an explanatory diagram of a main part configuration of a conventional infrared array sensor.

FIG. 7 is an explanatory diagram of a pyroelectric element in which electrodes are formed in a two-dimensional array on both front and back surfaces of a pyroelectric substrate.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pyroelectric element 5 Circuit board 8 Pyroelectric substrate 9 Ground electrode 10 Conductive adhesive 11 Connection part of conductive adhesive 15 Ground electrode forming surface

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁷ identification code FI G01V 8/20 G01V 9/04 P (58) Investigated field (Int.Cl. ⁷ , DB name) G01J 1/02 G01J 1 / 42 G01J 5/02 G01J 5/12 G01V 9/04 G01N 21/35 H01L 37/02

Claims (2)

(57) [Scope of request for utility model registration] 1. A ground electrode is formed on one side of a front and back surface of a pyroelectric substrate.
A plurality of ground electrodes arranged in a two-dimensional array on the ground electrode forming surface in a conductive state with each other ;
On the back side of the ground electrode forming surface of the substrate, multiple infrared detection signals
An output electrode is arranged and arranged at a position facing the ground electrode.
Is, the grounding electrode to the ground electrode formation surface of the pyroelectric substrate
A connection portion of a conductive adhesive for common connection to the ground potential electrode on the circuit board side is formed, and the infrared detection
Signal output electrodes are solder bumps arranged on the circuit board surface
FET gate fixed on the circuit board and provided on the circuit board
In the infrared array sensor which is electrically connected to the connection portion of the conductive adhesive before and after at least the ground electrode formation surface of the pyroelectric substrate, left and right, it either symmetric diagonal positions
An infrared array sensor formed on an outer peripheral edge of a ground electrode forming surface . 2. The pyroelectric substrate is a square substrate, and is made of a conductive material.
Connect the conductive adhesive to the four corners of the square ground electrode formation surface
Characterized in that it is formed at a bi-diagonally symmetric position of
The infrared array sensor according to claim 1.