JPH08242018A - Transmission type photo-interrupter - Google Patents

Abstract

PURPOSE: To provide a transmission type photo-interrupter which is smaller and thinner and can be surface-mounted. CONSTITUTION: A transmission type photo-interrupter 2 is provided with an insulation substrate 1 on the surface of which a conductive pattern 3 is formed, a light emitting element 5 which is mounted on the surface of the insulation substrate 1, and a photo-detecting element 9 which is mounted on the surface of the insulation substrate 1 for detecting the light from the light emitting element. On the insulation substrate between the light emitting element 5 and the photo-detecting element 9, a notch 29 into which a detector body is inserted is formed. The light emitting and photo-detecting elements are directly fixed and connected on the insulation substrate 1, for thinner shape. Further, since the transmission type photo-interrupter has no lead and not limited to a minimum lead pitch, miniaturization is possible. Furthermore, a conductor layer is formed on the surface of a recessed part 31 of the insulation substrate 1, thus surface mounting becomes possible.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmissive photo interrupter.

[0002]

2. Description of the Related Art Conventionally, a transmission type photo interrupter in which a light emitting element and a light receiving element are integrally sealed with resin has been widely used as a sensor for position detection and the like.

An example of such a transmissive photo interrupter is disclosed in Japanese Patent Laid-Open No. 252486/1988. In this transmissive photo interrupter, a light emitting element and a light receiving element are fixed and connected on a lead. The light emitting element and the light receiving element are integrally sealed together with the lead by using a transparent resin.

[0004]

The above-mentioned transmissive photo interrupter is a so-called lead frame mold type in which a light emitting element and a light receiving element are fixed and connected on a lead frame to be manufactured. However, if the lead frame mold type device is downsized, cracks may occur in the translucent resin that seals each lead when bending each lead for surface mounting on the printed circuit board. There was an improvement point that there is.

Further, in the lead frame mold type element, since it is necessary for each lead to be connected to a circuit on the printed circuit board without contacting each other, a certain space is required between each lead. This spacing also hinders the miniaturization and thinning of the lead frame mold type transmissive photointerrupter.

Therefore, an object of the present invention is to provide a transmissive photointerrupter capable of solving the above technical problems.

[0007]

In order to achieve the above object, a transmissive photointerrupter according to the present invention is mounted on the surface of an insulating substrate having an insulating substrate having a plurality of conductive patterns on the surface, The light emitting element electrically connected to the conductive pattern and the light emitting element so as to receive light from the light emitting element are mounted on the surface of the insulating substrate with a predetermined space and electrically connected to the conductive pattern. And a light receiving element, and a notch is formed in the insulating substrate between the light emitting element and the light receiving element.

Further, the light emitting element and the light receiving element are each sealed on the above-mentioned insulating substrate by a sealing member made of a light-transmissive resin, and each of the sealing members is formed in a curved shape in which the surfaces facing each other are convex. Alternatively, a light shielding film may be formed on the surface of the sealing member on the opposite side of the insulating substrate.

[0009]

The transmissive photo interrupter according to the present invention has an insulating substrate, and the surface of the insulating substrate is provided with a plurality of conductive patterns. The light emitting element and the light receiving element are fixed and connected to the conductive pattern. Since it can be mounted on an insulating substrate and a predetermined gap is provided between the light emitting element and the light receiving element mounted on the insulating substrate, insulation between the light emitting element and the light receiving element is provided. It is possible to insert a detection object by providing a notch in the flexible substrate.

Further, the light emitting element and the light receiving element are sealed with a light transmitting resin, and a light emitting surface for emitting the light from the light emitting element from the light transmitting resin and a light for the light receiving element are incident on the light transmitting resin. Since the light incident surface is formed in a convex curved shape, it is possible to suppress the divergence of the light emitted from the light emitting element and to condense the light incident on the light receiving element.

Further, a light-shielding film is formed on the surface of the sealing member opposite to the insulating substrate, so that the light inside the sealing member is transmitted to the outside and the outside light is sealed inside the sealing member. Is prevented from penetrating.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the drawings.

1 to 5 show a transmissive photo interrupter 2 according to the first embodiment of the present invention. 1 and 2 are perspective views showing the overall structure of the transmission type photo interrupter 2, and FIG. 3 is a perspective view showing the back surface of the transmission type photo interrupter 2.

The insulating substrate 1 shown in FIG.
It is made of composite material such as epoxy or highly insulating material such as ceramic, and has a cutout 2 at the center of the short side of the rectangle.
It is formed in a substantially U shape by providing 9.
As shown in FIGS. 1 and 2, a plurality of thin film-shaped conductive patterns 3 formed by gold (Au) plating are formed on the front surface of the insulating substrate 1, and on the back surface, as shown in FIG. The pattern 4 is formed. These conductive patterns 3, 4
May be made of other material as long as it has conductivity, and may be formed of copper (Cu) or a copper alloy, for example.

As shown in FIG. 2, the light emitting element 5 is fixed on the surface of the conductive pattern 3 by die bonding, and the light emitting element 5 and the conductive pattern 3 are electrically connected via their contact surfaces. It is connected to the. The wire 7 is made of a conductive material. One end of the wire 7 is fixed to the upper part of the light emitting element 5 by wire bonding, and the other end of the wire 7 is fixed to the conductive pattern 3. The wire 7 and the light emitting element 5, and the wire 7 and the conductive pattern 3 are electrically connected by wire bonding.

Further, a light receiving element 9 is fixed on the surface of the conductive pattern 3 by die bonding, and the light receiving element 9 and the conductive pattern 3 are electrically connected via their contact surfaces. . The wire 11 is made of a conductive material, like the wire 7 described above. One end of the wire 11 is fixed to the upper portion of the light receiving element 9 by wire bonding, and the other end of the wire 11 is a conductive pattern. It is fixed on 3. The light receiving element 9 and the conductive pattern 3 are connected to the wire 11 by wire bonding.
Is electrically connected to

As described above, since the light emitting element 5 and the light receiving element 9 are fixed and electrically connected to the conductive pattern 3 in the transmissive photointerrupter 2 of this embodiment, the intervals between the plurality of conductive patterns are small. Can be made extremely small, and the thickness of the transmissive photo interrupter 2 can be made equal to the thickness of the insulating substrate 1 and the light emitting element 5 (or the light receiving element 9).
And the thickness of

The notch 29 formed between the light emitting element 5 and the light receiving element 9 arranged at a predetermined distance on the insulating substrate 1 is for inserting a detection object. By setting, it is possible to prevent the light from being transmitted from the light emitting element 5 to the light receiving element 9. Therefore, the shape of the notch 29 does not have to be rectangular as long as it can insert the detection object, but the position of the lowermost edge portion 30 of the notch 29 (FIG. 1) is the same as the light emitting element 5 and the light receiving element. It is necessary to be located sufficiently downward (in FIG. 1) from the line segment connecting the element 9. Preferably, as shown in this embodiment, the position of the edge portion 30 is lower than the position of the lowermost side surface of the sealing members 13 and 15.

As shown in FIG. 2, the above-described light emitting element 5 is sealed on the insulating substrate 1 by a sealing member 13 formed by molding a translucent resin so as to surround the periphery thereof. The light receiving element 9 is sealed by a sealing member 15 made of a translucent resin so as to surround the light receiving element 9, whereby the light emitting element 5, the light receiving element 9 and the wires 7 and 11 are protected.

Further, as shown in FIG. 1, the light emitting surface 17 and the light incident surface 19, which are the facing surfaces of the sealing member 13 and the sealing member 15, are each formed in a curved shape, and the bending direction thereof is , The straight line included in each surface is the insulating substrate 1
Is parallel to the line orthogonal to the upper surface of the. Therefore, the light emitting surface 17 and the light incident surface 19 each function as a cylindrical lens, and suppress the divergence of light emitted from the light emitting surface 17 in the lateral direction (direction parallel to the upper surface of the insulating substrate 1) and It is possible to collect the light that is incident on the incident surface 19 in a laterally spread manner. In addition, the sealing members 13 and 15 having such a bending direction
Is convenient for resin molding by pulling the molding die upward on the insulating substrate 1.

When the light emitting element 5 is turned on, mainly the light receiving element 9
The light diverges in the direction of, and the light reaching the light emitting surface 17 is
The light output surface 17 functioning as a cylindrical lens changes the optical path so as not to diverge in the lateral direction, and outputs the light substantially parallel to the space between the light output surface 17 and the light input surface 19.
It is incident on the light incident surface 19. The light incident surface 19 also functions as a cylindrical lens, and the incident light is laterally condensed toward the light receiving element 9. When there is a detection object in the notch 29, the light emitted from the light emitting element 5 is blocked by the detection object and cannot be detected by the light receiving element 9, so it is detected that the detection object exists in the notch 29. To be done.

FIG. 4 is a cross-sectional view taken along the line AA shown in FIG. 2, in which the light shielding film 21 is formed on the upper surface of the sealing member 13 and is separated from the upper surface of the insulating substrate 1. The light emitted from the light emitting element 5 is prevented from being emitted to the outside. Similarly, the light shielding film 2 is formed on the surface of the sealing member 15.
3 is formed to prevent the light directed to the upper surface of the insulating substrate 1 from entering the sealing member 15. Further, FIG. 5 shows a cross-sectional view taken along the line BB shown in FIG.
A light shielding film 27 is formed on the side surface (right side surface in the drawing) of 5 to prevent light from entering the sealing member 15, and similarly, a light shielding film 25 is formed on the sealing member 13. This prevents the light inside the sealing member 13 from being emitted to the outside (not shown).

In this way, the light shielding films 21, 23, 25, 27
The light emitting surface 17 and the light incident surface 1 of the transparent resins 13 and 15
Since it is provided on the upper surface, side surface, etc. other than 9, the light reflected by the members (mounting parts, etc.) around the detection object is transmitted, and there is no risk of erroneously detecting the presence or absence of the detection object. These light-shielding films 21, 23, 25 and 27 may be coating films made of paint or ink as long as they have excellent characteristics of shielding the wavelength of light emitted by the light emitting element.

Further, as shown in FIG. 1, a semi-cylindrical concave portion 31 is formed on the long side of the rectangular insulating substrate 1, and the conductive pattern 3 is continuous on the inner surface of the concave portion 31. A conductive layer is formed by gold (Au) plating, and the conductive layer is also electrically connected to the conductive pattern 4 on the back surface of the insulating substrate 1. Therefore, each wiring (electrode) of the light emitting element and the light receiving element connected to the conductive pattern 3 on the front surface of the insulating substrate 1 has the conductive pattern 4 on the back surface of the insulating substrate 1.
Are each electrically connected to.

By providing such a conductive layer,
As shown in FIG. 1, when the insulating substrate 1 is directly fixed on the printed circuit board 32, the conductive pattern 4 on the back surface of the insulating substrate 1 and the pattern on the printed circuit board 32 are connected to each other. Can be implemented. Further, although it is similar to the case of the conductive patterns 3 and 4 described above, the material of the conductive layer is not limited to gold and may be another material having conductivity.

A mounting hole 33 is formed in the insulating substrate 1 at the position shown in the figure. By inserting a screw through the mounting hole 33 and fixing the screw to the printed circuit board 32 or the like, it becomes possible to firmly fix the insulating substrate 1 directly to the printed circuit board 32, and the positioning accuracy is improved. Can be improved.

Next, a second embodiment according to the present invention will be described.

FIG. 6 is a diagram showing a transmissive photo interrupter 40 according to the second embodiment. As with the first embodiment, the insulating substrate 1 is molded with a translucent resin.
An aspherical lens 45 having an opposing surface between the upper sealing member 41 and the sealing member 43 formed in a flat shape instead of a curved shape, one surface of which is a convex shape and the other surface of which is a flat shape, emits light. It is integrally molded at the same time as the resin molding of the portion, or is adhered to the surface of the light emitting surface 42 with a translucent adhesive. Due to the function of the aspherical lens 45, the light emitted from the light emitting element becomes parallel light having a spread in a direction parallel to the insulating substrate 1 as indicated by a plurality of arrows 49. The light incident surface of the sealing member 43 is formed in a planar shape, and the light receiving element 47 inside the sealing member 43 includes four elements 47a to 47a having a planar light receiving surface.
It is composed of 47d. Therefore, a plurality of arrows 49
Light having a lateral spread as shown by is received by the light receiving element 4
Irradiation is uniformly applied to all the elements 47a to 47d arranged in the lateral direction of No. 7.

Therefore, when each of the plurality of detection objects placed in the notch 29 is arranged so as to shield each of the light receiving elements 47 composed of the four elements 47a to 47d, a plurality of detection objects are detected. The presence / absence of each of the objects can be detected. Therefore, for example, a disk-shaped detection object having a plurality of slits of a predetermined pattern is arranged in the notch 29,
When the respective slits are aligned with the optical paths of the light receiving elements 47a to 47d, the angular position, angular velocity, etc. of the detected object can be detected. Therefore, such a transmissive photo interrupter 40 may be used for a rotary encoder or the like that detects a rotation angle, a rotation speed, and the like. The other structure of the second embodiment is similar to that of the first embodiment shown in FIGS.

Next, a third embodiment of the present invention will be described.

FIG. 7 shows a transmissive photo interrupter 50 according to the third embodiment. The difference from the first embodiment is that a spherical lens 51, one surface of which is convex and the other surface is flat, is formed. 51 is integrally molded with the resin molding of the light emitting portion and the light receiving portion, or is affixed to the facing surfaces of the sealing member 53 and the sealing member 54 formed in a flat shape by a translucent adhesive. It is a point.

The spherical lens 51 has the same condensing characteristics in the parallel direction and the orthogonal direction to the insulating substrate 1, and the light from the light emitting element (inside the sealing member 53) is emitted from the spherical lens 51. The parallel light flux becomes a parallel light flux, and the parallel light flux that is incident on the spherical lens 51 of the sealing member 54 that seals the light receiving element is condensed by the spherical lens 51 and heads for the light receiving element. Therefore, since the transmissive photo interrupter 50 includes such a spherical lens 51, the transmission photo interrupter 50 has, for example, a light emitting layer having a stripe structure and has an emission characteristic of emitting beam light.
When an ED (light emitting diode) is used, the light receiving characteristic of the light receiving element is significantly improved.

Next, a preferred embodiment of the manufacturing method for mass-producing the transmission type photo interrupter according to the embodiment of the present invention will be described below.

First, a plurality of conductive patterns 3 and 4 are formed by gold plating on both surfaces of an insulating substrate 61 in which a plurality of (15 shown in FIG. 8) rectangular holes 63, mounting holes 33, through holes 65 and the like are processed. To do. In this case, through hole 6
The inner surface of 5 is also plated with gold.

Next, the plurality of light emitting elements 5 and the light receiving elements 9 are fixed on the conductive pattern 3 by die bonding. The electrode side that is not electrically connected by fixing is connected to another conductive pattern 3 by wire bonding.

Next, the resin mold portion 71 is formed on the insulating substrate 61 so that the light emitting element 5 and the light receiving element 9 which are arranged adjacent to each other across the vertical cutting line 69 are integrally sealed.
Are continuously formed by transfer molding.

Next, the insulating substrate 61 is cut along the horizontal cutting lines 67 and the vertical cutting lines 69 using a dicing saw. Since the horizontal cutting line 67 extends along one of the short sides of the rectangular hole, the rectangular cutout 29 can be efficiently formed by cutting along the horizontal cutting line 67. The vertical cutting line 69 is
As described above, since the light emitting element 5 and the light receiving element 9 are located so as to straddle each other, the two resin sealing members 1 are cut by cutting.
Since the vertical cutting lines 69 are located on the central axis of the through hole 65, the recesses 31 can be formed efficiently at two locations by cutting once.

Thus, not only can a large number of transmissive photointerrupters be easily manufactured by using the large insulating substrate 61, but also the elements inside the transmissive photointerrupter can be arranged suitable for manufacturing by cutting. As a result, the process is greatly simplified and the manufacturing cost is significantly reduced.

Although the embodiments of the present invention have been described above, it goes without saying that the transmission type photo interrupter according to the present invention is not limited to the above-mentioned second and third embodiments. For example, a conductive pattern is formed on the back surface of the insulating substrate according to the first embodiment, but if wiring connection is possible when it is directly mounted on a printed circuit board, the conductive pattern is formed only on the front surface of the insulating substrate. May be formed. Further, in the embodiment of the manufacturing method, 15 transmissive photointerrupters are manufactured from a large insulating substrate, but the number is not necessarily limited to 15, and 15 or more are manufactured using a larger insulating substrate. You may do it.

[0040]

As described above, according to the present invention, a predetermined gap is provided between the light emitting element and the light receiving element, and the notch is formed in the insulating substrate between the light emitting element and the light receiving element. A sensing object can be inserted between the device and a transmissive photointerrupter, and the thickness of the transmissive photointerrupter according to this configuration is the thickness of the light emitting device (or the light receiving device) in addition to the thickness of the insulating substrate. However, it is possible to greatly reduce the thickness of the transmissive photo interrupter. Further, since the light emitting element and the light receiving element are fixed and connected on a plurality of conductive patterns provided on the surface of the insulating substrate, the distance between the patterns can be extremely narrowed, and the transmissive photointerrupter can be greatly reduced. It can be miniaturized.

Further, the light emitting surface and the light incident surface are formed in a convex curved shape to suppress the divergence of the emitted light from the light emitting element and to condense the incident light to the light receiving element. The utilization efficiency of the amount of light received by the light receiving element with respect to the amount of light emitted is increased.

Further, through the light-shielding film formed on the surface of the sealing member on the side opposite to the insulating substrate, the light inside the sealing member is transmitted to the outside and the outside light is sealed inside the sealing member. Since the light is prevented from being transmitted to the outside, it is possible to reduce the possibility of malfunction due to external light or an object placed outside the cutout.

[Brief description of drawings]

FIG. 1 is a diagram showing a transmissive photo interrupter according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a light emitting element and a light receiving element directly mounted on an insulating substrate in the transmissive photointerrupter according to the first embodiment of the present invention.

FIG. 3 is a view showing the back surface of the insulating substrate in the transmissive photointerrupter according to the first embodiment of the present invention.

4 is a diagram showing a cross section taken along a line AA shown in FIG.

5 is a diagram showing a cross section taken along a line BB shown in FIG.

FIG. 6 is a diagram showing a transmissive photo interrupter according to a second embodiment of the present invention.

FIG. 7 is a diagram showing a transmissive photo interrupter according to a third embodiment of the present invention.

FIG. 8 is a view showing a large insulative substrate having a large number of light emitting elements and light receiving elements for manufacturing a transmissive photo interrupter according to the present invention.

[Explanation of symbols]

1 ... Insulating substrate, 3, 4 ... Conductive pattern, 5 ... Light emitting element, 9 ... Light receiving element, 13, 15 ... Sealing member, 17 ... Light emitting surface, 19 ... Light incident surface, 29 ... Notch, 31 ... Recess, 2
1, 23, 25, 27 ... Shading film.

Claims (4)

[Claims] 1. An insulating substrate having a plurality of conductive patterns on a surface thereof, a light emitting element attached to the surface of the insulating substrate and electrically connected to the conductive pattern, A light-receiving element attached to the surface of the insulating substrate at a predetermined distance from the light-emitting element so as to receive light and electrically connected to the conductive pattern; A transmissive photointerrupter characterized in that a notch is formed in the insulating substrate between the element and the element. 2. The light emitting element and the light receiving element are sealed by a sealing member made of a translucent resin on the insulating substrate, and each of the sealing members has a curved shape in which surfaces facing each other are convex. The transmissive photointerrupter according to claim 1, wherein 3. The facing surface of the sealing member has a curved direction in which a straight line included in each facing surface is parallel to a line standing upright on the insulating substrate. The transmissive photo interrupter described. 4. The transmissive photointerrupter according to claim 2, wherein a light shielding film is formed on a surface of the sealing member opposite to the insulating substrate.