JPH11308679A - Optical microphone - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain high performance by cutting a sealing part with a base, forming an optically non-translucent film to a cut face, adhering a cut face of a light-emitting element sealing part and a cut face of a light-receiving element to the film integrally so as to avoid direct light from the light-emitting element to the light-receiving element that is a cause to a bias. SOLUTION: A light-emitting element 1 and a light-receiving element 2 mounted on a board 3 are sealed by a transparent resin 9, and the sealed part is cut off together with the base. At least an optical non-translucent film 6 is formed to one cut face. Since a formed face is exposed in the film, the film is easily formed without defects by any of methods such as coating or mounting or the like. The cut face of the sealing part of the light-emitting element and the light-receiving element is adhered to the film integrally. According to this manufacturing method, the complete optical non-translucent film 6 is formed between the light-emitting element 1 and the light-received element 2 and direct light from the light-emitting element 1 to the light-receiving element 2 is prevented and a problem of production of a bias component is solved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The microphone of the present invention
It is used in the field of small microphones used in car phones, mobile phones, and the like, and in the field of intruder detection utilizing pressure changes caused by intruders.

[0002]

2. Description of the Related Art In an optical microphone, a light emitting / receiving element mounted on a substrate is sealed with a transparent resin.
A light-impermeable film is provided between the light-emitting and light-receiving elements. Except for the light emitting part and light receiving part on the outer wall of the transparent resin sealing part,
A light-impermeable film is formed. Above the light emitting portion and the light receiving portion, a membrane having light reflectivity that vibrates due to sound, pressure, or the like is held by a membrane support. Light from the light emitting element is emitted from the light emitting part, reflected by the membrane film, and reaches the light receiving element from the light receiving part. When the membrane film position moves due to vibration, the reflection position also moves, and the output of the light receiving element changes. The principle of the optical microphone is to detect sound, pressure and the like by reading this output. FIG. 2 shows a conceptual diagram of this optical microphone. In a conventional optical microphone, the light-impermeable film of the transparent resin sealing portion is formed with a groove having a width of about 0.1 mm using a dicing saw, a wire saw, or the like, and a light-impermeable material is applied to the walls of the groove. And vapor deposition. In application, it is difficult to form a film to the deep part of the groove due to the effect of air bubbles, and in vapor deposition, it is not possible to form a complete light-impermeable film, and light from the light emitting element is directly transmitted to the light receiving element. As a result, a bias component was generated, and as a result, a signal component was reduced. The light emitting portion and the light receiving portion are manufactured by processing the transparent resin sealing portion once into a conical or polygonal pyramid shape, then applying a light non-transmissive film over the entire outer wall, and then planarizing by polishing. ing. This method, due to the polishing amount error,
There is a drawback that the light emitting portion and the light receiving portion area which contribute to the performance of the optical microphone cannot be manufactured stably.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to solve the conventional disadvantages of small signal components and low production stability.

[0004]

A light-emitting element and a light-receiving element mounted on a substrate are sealed with a transparent resin, and the sealing portion is cut including the substrate, and at least one cut surface is non-transparent. The bias component is reduced by the manufacturing method including the step of forming the conductive film and the step of bonding and integrating the cut surface of the light emitting element sealing portion and the light receiving element sealing portion thereafter, resulting in an increase in the signal component. In addition, a structure is adopted in which the upper part of the transparent resin sealing portion in which the light emitting element and the light receiving element are built is a plane, and a polygonal column or a columnar projection is provided in this plane, and the projections are a light emitting section and a light receiving section. This eliminates the disadvantage that the production stability of the light emitting portion and the light receiving portion is low.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION A light emitting element and a light receiving element mounted on a substrate are sealed with a transparent resin and cut including the sealing substrate. A light-impermeable film is formed on at least one cut surface. In this film formation, since the formation surface is exposed,
A film that is easy and free from defects is formed by any method such as mounting. Thereafter, the cut surface of the light emitting element sealing portion and the light receiving element sealing portion are bonded and integrated. According to this manufacturing method, a complete light non-transmissive film is formed between the light emitting element and the light receiving element, light from the light emitting element is prevented from directly reaching the light receiving element, and generation of a bias component is solved. The upper part of the transparent resin sealing portion containing the light emitting element and the light receiving element is a flat surface, and a polygonal column or a columnar projection is provided in this plane. A light non-transmissive film is formed on the entire outer wall of the transparent resin sealing portion by a method such as coating or vapor deposition. Thereafter, polishing is performed to produce a light emitting portion and a light receiving portion. In this method, even if there is a polishing amount error, the area of the light emitting portion and the light receiving portion does not change, and the area stability of this portion increases.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Die bonding and wire bonding are carried out on a substrate such as a printed circuit board using a LED or the like as a light-emitting element and a photodiode or the like as a light-receiving element. These are sealed with a transparent resin such as epoxy. The sealing portion is cut along with the substrate using a semiconductor manufacturing device such as a dicing saw or a wire saw. A light-impermeable film is formed on at least one cut surface. Since the formation surface is exposed, a film which is easy and has no defect can be formed by any method such as coating and mounting. Thereafter, the cut surface of the light emitting element sealing portion and the light receiving element sealing portion are bonded and integrated. Further, the transparent resin sealing portion containing the light emitting element and the light receiving element is made flat by using a dicing saw, a wire saw or the like. At this time, if a region where processing is not performed is provided, a polygonal column protruding portion is obtained at that portion. Similarly, the use of a mechanical lathe provides cylindrical projections and planes. These polygonal columns and cylinders can be obtained easily and with high precision. Next, a light-impermeable film is formed on the entire outer wall of the transparent resin sealing portion by a method such as coating and mounting. Thereafter, when polishing is performed, a light emitting portion and a light receiving portion are manufactured, and the other outer walls are in a state of being covered with a light non-transmissive film. FIG. 1 is a conceptual diagram of an optical microphone manufactured in an embodiment of the present invention. FIG. 1 shows an example in which a transparent resin sealing portion is cut including a substrate, a light-impermeable film is formed, a surface is provided after bonding and integration, and a column or a polygonal column is further formed. A method of providing a flat surface, further providing a polygonal column or a cylinder, and using them as a light emitting portion and a light receiving portion is to form a conventional groove and form a light-impermeable film in the groove portion if the bias component is within an allowable range. The method also applies.

[0007]

As described above, according to the present invention, there is no light from the light emitting element, which causes a bias, directly to the light receiving element, and high performance is achieved. Further, it is possible to produce the light emitting portion and the light receiving portion with a constant area.

[Brief description of the drawings]

FIG. 1 shows an embodiment of an optical microphone according to the present invention.

FIG. 2 is a conceptual diagram of a configuration of an optical microphone.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Light emitting element 2 Light receiving element 3 Substrate 4 Membrane support 5 Membrane 6 Light non-transmissive film 7 Light emitting part 8 Light receiving part 9 Transparent resin

Claims (2)

[Claims] An optical microphone comprising a light emitting element, a light receiving element, a substrate on which the light emitting element and the light receiving element are mounted, and a membrane film, wherein the light emitting element and the light receiving element mounted on the substrate are sealed with a transparent resin, and the sealing portion is formed on the substrate. Cutting and including, forming a light-impermeable film on at least one cut surface,
And thereafter bonding and integrating the cut surfaces of the light emitting element sealing portion and the light receiving element sealing portion. 2. An optical microphone comprising a light-emitting element, a light-receiving element, and a membrane film, wherein the upper surface of a transparent resin sealing portion incorporating the light-emitting element and the light-receiving element is a plane, and a polygonal column or a cylindrical projection is provided in the plane. An optical microphone, wherein the projecting portion is a light emitting portion and a light receiving portion.