JP2000340844A - Infrared ray transmission element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lower profile and reduce costs by a method wherein a circuit substrate forming an electric circuit is integrally provided with an optical func tion part such as light condensing reflection, and selective transmission. SOLUTION: A light emitting element 21, a light receiving element 22, and a signal processing chip 20 are fitted on one plane of an infrared rays transmission element. A circuit substrate 1 is provided on the one plane with a circuit pattern 23 for connecting thereto, and is formed by injection molding using a resin such as transparent and insulated polycarbonte, acrylic, sulfone material or the like, called as an MID substrate. A projection 11 is provided with a reflection film 12 on the surface, constituting a reflection mirror 3 as a reverse face mirror. The reflection mirror 12 is formed by plating, vapor, or the like, and, when increasing noise-resistance as collectively having a filter characteristic of selectively reflecting only a predetermined wavelength (infrared lights), the reflection mirror 12 is formed as a high dielectric multilayer film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an infrared transmission device for transmitting infrared light.

[0002]

2. Description of the Related Art In an infrared transmission device for emitting or receiving infrared light or for emitting and receiving infrared light, a circuit board on which an element for emitting or receiving light is mounted and an electric circuit is formed is attached to an infrared transmission device. It is formed as an optical functional component such as a lens or a reflector for condensing or distributing light.

[0003]

In this case, a process for mounting the optical functional component on the circuit board is required, and it is difficult to reduce the profile due to the presence of the optical functional component which is a separate component.

[0004] The present invention has been made in view of such a point, and its object is to achieve a low profile despite having an optical function unit.
Another object of the present invention is to provide an inexpensive infrared transmission device.

[0005]

According to the present invention, a circuit board on which an element for light emission or light reception is mounted and an electric circuit is formed is provided with a light condensing or reflecting element for the element. It has a feature in that it is provided with an optical function unit such as a laser beam and selective transmission.

Since the circuit board has the optical function part, it is not necessary to separately add an optical function part.

[0007] The optical function portion here is preferably formed by providing a reflection film on the surface of the circuit board opposite to the device mounting surface, and is preferably a reflecting mirror having the device mounting surface as an infrared incident / outgoing surface. However, the circuit board is composed of a first substrate having a concave surface, and a second substrate fitted with the concave surface and integrated with the first substrate and having an element mounted thereon. A reflecting mirror formed at the interface between the substrate and the second substrate and reflecting light may be used.

An optical function unit having different optical functions may be provided on one side and the other side of the circuit board. In this case, a reflecting mirror is formed on one side of the circuit board, and the other side of the circuit board is provided. A lens can be formed on one side of the circuit board, a reflecting mirror can be formed on one side of the circuit board, and a prism can be formed on the other side of the circuit board.

Preferably, the element is sealed with a reflective laminate.

Further, the circuit board may be provided with a pair of projections as electrodes on a mounting portion of the element, and the element may be inserted between the projections.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to an embodiment. FIG. 1 shows an example of an infrared transmission device according to the present invention.
And a signal processing chip (IC) 20 are mounted on one side, and a circuit pattern 23 for connecting them is provided on one side. The circuit board 1 is called an MID substrate, and has a transparent insulating property. It is formed by injection molding of a resin such as polycarbonate, acrylic, or polysulfone, and has a hemispherical projection 11 formed on the other surface at the same time as the injection molding. The protrusion 11
Constitutes a reflecting mirror 3 as a backside mirror by providing a reflecting film 12 on the surface thereof, and the circuit board 1 is mounted on one side of the circuit board 1 on which the light emitting and receiving elements 21 and 22 are attached.
Incident on the light receiving element 22 is reflected by the reflecting mirror 3.
And the light emitted from the light emitting element 21 is reflected by the reflecting mirror 3 and emitted from the one side.

The reflection film 12 is formed by plating or vapor deposition. If the reflection film 12 has a filter characteristic of selectively reflecting only a specific wavelength (infrared light) to enhance noise resistance, a high dielectric multilayer film is used. Form as FIG. 2 shows an example in which the circuit board 1 is made of an acrylic resin (refractive index 1.45), and Al ₂ O _{3 is formed} on the first high dielectric film 12a of MgF ₂ (refractive index 1.39). (Refractive index 1.6
2) The second high dielectric film 12b is formed, and the thickness of these high dielectric films 12a and 12b is set to １ ／ of the wavelength of light to be reflected.

A circuit board 1 having a circuit pattern 23 on one side and a reflecting mirror 3 as an optical function part.
Can be formed as follows. That is,
As shown in FIG. 3 (a), a molded product 1 'for a circuit board in which the protrusions 11 are integrated as shown in FIG. 3 (a) by injection molding of a resin such as transparent insulating polycarbonate, acrylic or polysulfone.
Is formed, and then the molded article 1 'is subjected to alkaline degreasing to wash oil and the like attached to the surface. Next, as shown in FIG. 3B, a reflection film (for example, Al, Ag,
An Au film) 51 is formed. The thickness of the reflection film 51 is preferably several tens nm to several hundreds nm. As shown in FIG. 3C, a conductive plating base film 52 is formed thereon. The plating base film 52 is a film that easily absorbs laser light, for example, C
It is formed by vacuum deposition or sputtering of u and Sn.

Next, as shown in FIG. 3D, laser patterning is performed on the surface of the conductive base film 52,
The portion of the base film 52 irradiated with the laser light is removed.
As a laser beam, a second or third harmonic YAG laser, a laser having good absorbability in the plating base film 52, such as a YAG laser, is used, and scanning is performed using a galvanometer mirror or the like. By irradiating a laser beam to a boundary portion with a portion other than the circuit portion, the plating base film 52 at the boundary portion is removed. At this time, the reflection film 51 under the plating base film 52 prevents the laser light from damaging the molded product 1 '.

Further, as shown in FIG. 3E, after the reflection film 51 at the boundary is removed by acid etching,
As shown in FIG. 3 (f), power is supplied to the circuit portion, and a circuit pattern 23 is formed by electrolytic copper plating, electric nickel plating, electric gold plating, etc., and then, as shown in FIG. 3 (g). Then, the remaining underlying film 52 covering the non-circuit portion and the reflective film 51 is removed by soft etching with ammonia persulfate or the like, and further, as shown in FIG. The film 51 is removed by acid etching.

In this case, the reflecting film 12 for the reflecting mirror 3 uses the above-mentioned reflecting film 51. However, when the reflecting film 12 is formed as a high dielectric multilayer film, FIG. b)
As shown in FIG. 4, after the reflection film 12 made of a high dielectric multilayer film is formed on the molded product 1 ', the reflection film 51 is formed (see FIG. 4).
(c)), formation of the base film 52 (FIG. 4D), laser patterning (FIG. 4E), etching of the reflection film 51 (FIG. 4).
(f)), the formation of the circuit pattern 23 by electroplating (FIG. 4 (g)), the removal of the unnecessary total underlayer 52 (FIG. 4 (h)), and the removal of the unnecessary total reflection film 51 (FIG. 4 (i) )).

FIG. 5 shows the case where the width of the protrusion 11 is the same as the width of both ends of the circuit board 1. Although the light collection efficiency of the reflecting mirror 3, which is an optical function unit, is reduced, a smaller infrared transmission device can be obtained.

When the light emitting and receiving elements 21 and 22 are mounted on the circuit board 1, an electrical connection with the circuit pattern 23 is required, and the signal processing chip (IC) 20 is generally used.
As in the case of the connection with the circuit pattern 23, the bonding is performed by wire bonding, soldering or the like, but as shown in FIG. 6 or FIG. (The inner wall surface of the recess 15 may be formed), and a portion of the surface of the circuit board 1 facing the recess 15 or the protrusion 16 may be provided with the circuit pattern 2.
3 is formed, the elements 21 and 22 are inserted between the recesses 15 and the protrusions 16 and 16 and are electrically joined with the conductive adhesive 24, so that the elements 21 and 22 can be easily mounted. Become. In the figure, reference numeral 25 denotes electrodes of the elements 21 and 22.

FIG. 8 shows that the devices 21 and 22 are inserted into the recesses 15 formed in the circuit board 1 and mounted, and then the reflection laminate 17 is attached to the opening surfaces of the recesses 15 to mount the devices 21 and 22.
Is shown. The optical efficiency of the elements 21 and 22 can be improved.

The optical function section formed on the circuit board 1 may be a lens, a prism, a selective transmission filter, or the like, in addition to the reflection mirror 3. FIG. 9 shows an example in which two of the reflecting mirror 3 and the lens 30 are provided as an optical function part. The reflecting mirror 3 is provided on the other surface of the circuit board 1 on which the circuit pattern 23 is formed on one surface, On the side different from the portion where the circuit pattern 23 is formed and the portion where the elements 21 and 22 are provided,
Is provided. When light distribution is required, the required light distribution characteristics can be obtained by the lenses 30 and 30.

As shown in FIG. 10 or FIG. 11, a prism 3 is provided on one side of a circuit board 1 provided with a reflecting mirror 3 on the other side.
1 may be formed integrally. Also in this case, the necessary light distribution control can be performed by the prism 31.

FIG. 12 shows another example. This is composed of a first substrate 1a having a concave surface 18 and a second substrate 1b fitted into the concave surface 18 and integrated with the first substrate 1a, and the optical function part is composed of the first substrate 1a and the second substrate 1a. The reflector 3 is formed at the boundary surface of the substrate 1b and reflects light.
The second substrate 1b on which the resins 21 and 22 are mounted is formed of a transparent resin that transmits infrared rays, but the first substrate 1a does not have to be transparent. First substrate 1a and second substrate 1b
Since the reflecting mirror 3 is formed on the boundary surface of the above, a mirror having a high reflectivity can be reliably obtained.

The circuit board 1 in this case may be formed as follows. That is, as shown in FIG.
Injection molding of a molded article 1a 'having a concave surface 18 is performed by using an insulating resin such as polyphthalamide, polyamide, liquid crystal polymer, polyimide, or polyetherimide, and then the molded article 1a which has been degreased with alkali is shown in FIG. As shown in (1), a reflective film 12 of high reflectivity made of aluminum or the like is formed by vacuum evaporation or sputtering. Reflective film 51
Has a thickness of several tens nm to several hundreds nm. Then, FIG.
As shown in (c), injection molding is again performed to form a molded product 1b 'that fills the concave surface 18.

Thereafter, as in the case described above, the molded article 1
13 (d), the formation of a plating base film 52 (FIG. 13 (e)), laser patterning (FIG. 13 (f)), and etching of the reflection film 51 (FIG. 13).
(g)), preparation of the circuit pattern 23 by electroplating (FIG. 13 (h)), removal of all unnecessary underlayers 52 (FIG. 13 (i)),
The unnecessary total reflection film 51 is created by a procedure of removing (FIG. 13 (j)).

[0025]

As described above, according to the present invention, a circuit board on which an element for light emission or light reception is mounted and an electric circuit is formed is provided with a light condensing, reflection and reflection for the element. Since the optical function unit such as selective transmission is integrally provided, it is not necessary to separately add an optical function component, and therefore, even though the optical function unit is provided, the profile can be reduced, Further, since there is no need to separately manufacture and attach an optical functional component, the optical functional component can be provided at low cost.

Here, the optical function portion is formed by providing a reflection film on the surface of the circuit board opposite to the device mounting surface, and may be a reflecting mirror having the device mounting surface as an infrared incident / outgoing surface. Although it is easy to manufacture because of the simplicity of its shape, a first substrate having a concave surface on a circuit board and a first substrate mounted on the concave surface and integrated with the first substrate and having an element mounted thereon are provided. The optical function part may be a reflecting mirror formed at the boundary surface between the first substrate and the second substrate to reflect light. In this case, it is necessary to surely obtain a higher reflectance. Can be.

Optical function units having different optical functions may be provided on one side and the other side of the circuit board, respectively, so that both light collection and light distribution control can be performed. In this case, a reflecting mirror is formed on one side of the circuit board and a lens is formed on the other side of the circuit board, or a reflecting mirror is formed on one side of the circuit board and a prism is formed on the other side of the circuit board. In this case, manufacturing is also easy in terms of simplicity of the shape.

If the element is sealed with a reflective laminate, the optical efficiency can be easily improved.

Further, the circuit board is provided with a pair of projections as electrodes on the mounting portion of the element, and if the element is inserted between the projections, the circuit pattern on the circuit board of the element can be obtained. Electrical connection and device attachment can be easily performed.

[Brief description of the drawings]

FIG. 1 is a perspective view of an example of an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view of the reflection film of the above.

FIG. 3 is a sectional view showing a manufacturing process of the circuit board according to the first embodiment;

FIG. 4 is a sectional view showing another manufacturing step of the circuit board according to the first embodiment;

FIG. 5 is a perspective view of another example.

FIG. 6 is a perspective view of still another example.

FIGS. 7A and 7B are cross-sectional views of an element mounting portion according to the first embodiment;

FIG. 8 is a perspective view of another example.

FIG. 9 is a perspective view of still another example.

FIG. 10 is a perspective view of another example.

FIG. 11 is a perspective view of still another example.

FIG. 12 is a perspective view of another example.

FIG. 13 is a cross-sectional view showing a step of manufacturing the circuit board of the above.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Circuit board 3 Reflector 21 Light emitting element 22 Light receiving element 23 Circuit pattern

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kimiaki Nakata 1048 Kazumasa Kadoma, Osaka Prefecture Matsushita Electric Works Co., Ltd. 72) Inventor Shunsuke Matsushima 1048 Kazuma Kadoma, Kadoma City, Osaka Prefecture F-term in Matsushita Electric Works Co., Ltd. JA03 JA06 LA01

Claims (8)

[Claims] 1. A circuit board on which an element for light emission or light reception is mounted and on which an electric circuit is formed, integrally forms an optical function unit such as light collection, reflection and selective transmission for the element. An infrared transmission device, comprising: 2. The optical function unit according to claim 1, wherein the optical function unit is formed by providing a reflection film on a surface of the circuit board opposite to the element mounting surface, and is a reflecting mirror having the element mounting surface as an infrared incident / outgoing surface. The infrared transmission device according to claim 1, wherein 3. A circuit board, comprising: a first substrate having a concave surface;
A second substrate on which the elements are mounted while being integrated with the first substrate and fitted into the concave surface, wherein the optical function part is formed at a boundary surface between the first substrate and the second substrate and reflects light; The infrared transmission device according to claim 1, wherein the infrared transmission device is a reflection mirror. 4. The infrared ray according to claim 1, wherein an optical function section having a different optical function is provided on one side and the other side of the circuit board. Transmission element. 5. A reflecting mirror is formed on one side of the circuit board,
5. The infrared transmission device according to claim 4, wherein a lens is formed on the other surface of the circuit board. 6. A reflecting mirror is formed on one side of the circuit board,
The infrared transmission device according to claim 4, wherein a prism is formed on the other surface of the circuit board. 7. The infrared transmission device according to claim 1, wherein the device is sealed with a reflective laminate. 8. The circuit board according to claim 1, wherein a pair of projections as electrodes are provided on a mounting portion of the element, and the element is inserted between the projections. Item 8. The infrared transmission element according to Item.