JP2005203511A - Structure for mounting optical device on optical element circuit board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stably ensure prescribed field vision characteristics without requiring any additional process such as optical axis adjustment by reliably and easily improving optical device positioning accuracy. <P>SOLUTION: In the periphery of a region planned for mounting a thermopile array chip 7 on a circuit board 6 having a conductor pattern 9, at locations corresponding to the four corners of orthogonally meeting edges of the thermopile array chip 7, chip positioning protrusions 10 are formed in advance on the conductor pattern 9 on the circuit board 6, whereto the thermopile array chip 7 is to be soldered. The thermopile array chip 7 is mounted in the prescribed region on the circuit board 6 with the chip positioning protrusions 10 serving as fit-in guides. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention provides a light receiving light such as a thermopile chip at a predetermined position on a circuit board having a conductor pattern, such as a thermopile infrared detector, a pyroelectric infrared detector, a phototransistor, a photodiode and a module thereof. The present invention relates to an optical device mounting structure in an optical element mounted with a device.

  In this type of optical element, when mounting an optical device on a circuit board having a conductor pattern, high positional accuracy is required for mounting the optical device in order to obtain a predetermined visual field characteristic as an optical device. Is done.

  Conventionally, generally, an adhesive is applied to an optical device mounting planned part on a flat circuit board, the optical device is mounted on the adhesive application surface and pressed to temporarily bond, and then the adhesive is cured by natural drying. A mounting means for adhering and fixing an optical device to a circuit board has been employed (see, for example, Patent Document 1).

Japanese Utility Model Publication No. 61-102830

  However, since the optical device mounting structure on the circuit board in the conventional optical element described above is a simple mounting pressing method, the optical device to be handled may be very small, and the positional accuracy of the mounting is ensured to be constant. This is difficult, and individual differences (variations) are likely to occur in the positional accuracy by the mounting operator. Further, even if the accuracy of the optical device mounting position can be ensured, there is a possibility that the optical device is displaced due to an impact or the like applied during the curing of the adhesive. If the positional accuracy variation during mounting or misalignment during curing of the adhesive occurs, the predetermined visual field characteristics as an optical device cannot be obtained. As a problem, an extra work process such as optical axis adjustment is required. Moreover, if the positioning accuracy of the mounting is poor, this becomes an obstacle at the time of wire bonding for electrically connecting the optical device and the conductor pattern of the circuit board, and it is likely to cause inconvenience in the electrical connection between the bonding wire and the conductor pattern. There was a problem.

  The present invention has been made in view of the above circumstances, and its purpose is to reliably and easily increase the positioning accuracy of the optical device and to obtain a predetermined visual field characteristic without requiring an extra work step such as optical axis adjustment. It is an object of the present invention to provide an optical device mounting structure on a circuit board in an optical element capable of ensuring the above in a stable manner.

  In order to achieve the above object, an optical device mounting structure on a circuit board in an optical element according to the present invention provides an optical element mounting structure on an optical element in which an optical device is mounted at a predetermined position on a circuit board having a conductor pattern. In the optical device mounting structure, soldering onto a solderable conductor pattern formed on the circuit board in advance corresponding to the part of the peripheral part or the entire circumference of the optical device mounting planned part on the circuit board Thus, an optical device positioning projection is formed, and the optical device is mounted at a predetermined position on the circuit board using the positioning projection as a fitting guide.

  According to the present invention having the above-described characteristic configuration, the optical device is fitted into the circuit board by using the positioning protrusion formed by soldering as a guide, so that the positioning at the time of mounting is not only easy. It is possible to reliably prevent the positional deviation during the curing of the agent and to increase the positioning accuracy of the optical device mounting. This eliminates the need for extra work steps such as optical axis adjustment after mounting, and makes sure that the electrical coupling between the bonding wire and the conductor pattern can be ensured without any obstacles during wire bonding. In particular, a conductive pattern that can be soldered is formed in advance on the circuit board, rather than bonding a sheet member with a protrusion separate from the board to form a positioning protrusion on the circuit board. By adopting the means for forming the positioning projection by soldering to the optical device, the positioning projection itself can be formed with high positional accuracy by utilizing the volume shrinkage characteristic and the wetting characteristic due to the surface tension of the solder. Mounting positioning accuracy can be remarkably increased. Therefore, there is an effect that a high-performance optical element that secures a predetermined visual field characteristic can be obtained with high productivity and low cost.

  In the optical device mounting structure on the circuit board in the optical element according to the present invention, a solderable conductor pattern is formed in advance on the circuit board in order to form an optical device positioning projection by soldering. As described in 2, the formation of other circuit components on the circuit board in the same process eliminates the need to add an extra process to the manufacturing process of the entire optical element. The productivity of the element can be further improved.

  Further, in the optical device mounting structure on the circuit board in the optical element according to the present invention, the positioning projections formed on the circuit board are formed in a closed loop line shape so as to surround the entire periphery of the peripheral part of the optical device mounting planned part. The positioning protrusions may be formed in a case where the optical device has a rectangular shape. As described above, it is desirable that the rectangular optical device be formed in pieces near the corners of the device corresponding to both sides of the device that are positioned orthogonally across the corners. In this case, avoiding the angular corners of the optical device can prevent the corners from colliding with the protrusions when the optical device is mounted, making it difficult to fit, and damaging the corners of the optical device. The protrusions do not get in the way during wire bonding, and predetermined wire bonding can be performed easily and reliably.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 is an overall exploded perspective view showing an embodiment applied to a thermopile type infrared detector A as an optical element according to the present invention, FIG. 2 is a plan view of a state in which a part (a metal case described later) is removed, FIG. FIG. 4 is a longitudinal sectional view in an assembled state. The thermopile type infrared detector A shown in each of these figures has a rectangular opening 2 formed on the upper surface of a metal case 1 opened downward, and an infrared transmitting material that closes the opening 2. A window member 3 is fixed to the upper lower surface (inner surface side) of the metal case 1. A stem 4 is attached to the lower opening of the metal case 1. The stem 4 has a plurality (24 in this case) of lead pins 5 whose front ends protrude into the metal case 1 and are held in an insulated state with respect to the stem 4 by an insulating material such as glass. Has been.

  In the metal case 1, a circuit board 6 is provided that is held in a horizontal state with its lower surface abutting against the protruding upper end portion 5 a of the lead pin 5. The circuit board 6 is formed in a rectangular shape (which may be square or circular) using a flat PCB or the like, and has a rectangular thermopile array chip 7 which is an example of an optical device and amplifiers on its upper surface. A conductor pattern 9 for electrically connecting other circuit components 8 is printed, and this conductor pattern 9 is electrically connected to the lead pin 5 through a well-known conductive means (not shown). Yes.

  In the thermopile infrared detector A configured as described above, a part of the periphery of the portion to be mounted of the thermopile array chip 7 on the upper surface of the circuit board 6, specifically, near the four corners of the rectangular thermopile array chip 7. Chip positioning protrusions 10 having a height of several tens to 100 μm are formed by soldering at a total of eight positions corresponding to both sides orthogonal to each other across each corner, and these eight protrusions 10 are inserted into the guides. As described above, the thermopile array chip 7 is mounted at a predetermined position on the circuit board 6 and bonded and fixed to the circuit board 6 through an adhesive.

  Here, the chip positioning protrusions 10 are formed in advance by soldering on the metal conductor patterns that are formed so as to be solderable in the above-described eight positions on the upper surface of the circuit board 6. The metal conductor pattern is formed in the same process as the process of mounting other circuit components 8 such as the above-described amplifiers on the upper surface of the circuit board 6.

  Then, after the thermopile array chip 7 is mounted on the circuit board 6 in a predetermined positioning state via the protrusions 10 and is completely fixed through curing of the adhesive, the opposite side of the thermopile array chip 7 and the circuit board 6 are fixed. Wire bonding is performed between the upper conductive pattern 9 and the both 7 and 9 are electrically and mechanically coupled to complete the thermopile infrared detector A.

  In the thermopile infrared detector A having the above-described configuration, the thermopile array chip 7 is fitted with the chip positioning protrusion 10 formed on the circuit board 6 by soldering as a guide, so that positioning at the time of mounting is easy. In addition, the thermopile array chip 7 can be reliably prevented from being displaced in the course of curing the adhesive, so that the mounting positioning accuracy can be improved, and an extra work step such as optical axis adjustment after mounting is unnecessary. At the same time, there is no obstacle during wire bonding due to misalignment, and the electrical coupling between the bonding wire and the conductor pattern 9 can be ensured and optimized.

  In particular, a conductor pattern that can be soldered on the circuit board 6 is formed in advance in the same process as the mounting of other circuit components 8 such as amplifiers, and the positioning projection 10 is formed by soldering on the conductor pattern. Therefore, the positioning accuracy of the mounting of the thermopile array chip 7 can be remarkably improved by utilizing the volume shrinkage characteristic and the wetting characteristic due to the surface tension of the solder to increase the positioning accuracy of the positioning pile 10 itself, and the solderable conductor An extra step is not required only for the formation of the pattern, and a high-performance thermopile infrared detector A that secures a predetermined visual field characteristic can be obtained with high productivity and at low cost.

  In the above-described embodiment, the thermopile type infrared detector A using the thermopile array chip 7 is applied. However, the present invention may be applied to an infrared detector or a pyroelectric infrared detector using a single thermopile. The present invention is also applicable to an optical element on which a light receiving optical device such as a phototransistor or a photodiode is mounted, and these modules.

  In the above-described embodiment, the positioning protrusion 10 is shown as being formed in pieces on a part of the peripheral part of the optical device such as the thermopile array chip 7, but the entire periphery of the peripheral part of the optical device is surrounded. Alternatively, it may be formed in a closed loop line shape.

It is a whole exploded perspective view showing an example applied to a thermopile type infrared detector as an optical element concerning the present invention. It is a whole top view in the state where a part was removed. It is a whole longitudinal cross-sectional view of an assembly state.

Explanation of symbols

6 Circuit board 7 Thermopile array chip (an example of optical device)
8 Other circuit components 9 Conductor pattern 10 Protrusion for positioning A Thermopile infrared detector (an example of an optical element)

Claims (3)

  In an optical device mounting structure on a circuit board in an optical element in which an optical device is mounted at a predetermined position on a circuit board having a conductor pattern, a part or the entire circumference of the peripheral part of the optical device mounting scheduled part on the circuit board In addition, the optical device positioning projection is formed by soldering onto a solderable conductor pattern previously formed on the circuit board corresponding to the portion, and the optical device is used as a guide by inserting the positioning projection into the circuit board. An optical device mounting structure on a circuit board in an optical element, wherein the optical device is mounted at a predetermined position.   The optical device mounting structure on a circuit board in the optical element according to claim 1, wherein the solderable conductor pattern is formed in the same process as mounting of other circuit components on the circuit board. The optical device has a rectangular shape, and the positioning protrusions are formed in pieces at locations corresponding to both side portions of the rectangular optical device that are positioned orthogonally across each corner portion. An optical device mounting structure on a circuit board in the optical element according to 1 or 2.

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