JPH06232445A - Optical element and transmission type optically coupled device - Google Patents

Abstract

PURPOSE:To provide a path for light to pass which attains high accuracy in positioning by a method wherein there are a light passing part parallel to a chip surface of an optical chip or which is curved-surface and can condense light and an inclined plane which inclines forward regarding the chip surface by a specified angle, which is adjacent to the light passing part or is adjacent with a level difference to that, formed on front surface of a translucent resin body. CONSTITUTION:When inclined parts 32, 33 have an angle 30-60 regarding chips 21, 25, light projected from the light emitting chip 21 goes inside a translucent resin 28. Among this light, the light reaching the light passing part 30 on light emitting side comes out from the translucent resin 28 onto a path T of an object to be detected in the air. Also, the light reaching the inclined part 32 are wholly reflected by refractive index of the air and the light-penetrative resin 28, so that the light does not come out from the translucent resin 28 onto the path T of the object for detection. Accordingly, on the path T of the object for detection, a path of light from the light passing part 30 on light emitting side toward the light passing part 31 on light accepting side is formed. When the detection object interrupts the light on the path, the output of the light receiving chip 25 changes.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical element such as a light emitting element or a light receiving element, and a transmission type optical coupling device using these elements for detecting the presence or absence of an object to be detected without contact.

[0002]

2. Description of the Related Art As shown in FIG. 8, a conventional transmissive photointerrupter has a light-emitting chip (eg, visible or infrared LED chip) 1 and a light-receiving chip (photodiode, phototransistor, or a signal processing circuit with them). The IC) 2 is die-bonded to the lead frames 3 and 4, respectively, and wire bonding is performed. Then, these are primary-molded with a translucent resin to form the light-emitting element 5 and the light-receiving element 6, and they are arranged opposite to each other and secondary-molded with a light-shielding resin to form the exterior resin body 7.

At this time, a window 8 which is not molded with a light-shielding resin is formed between the light emitting surface 1a of the light emitting chip 1 and the light receiving surface 2a of the light receiving chip 2 as a light passage surface, and the light emitting surface 1a to the light receiving surface are formed. It formed a passage for light to 2a.

Further, as shown in FIG. 9, a slit 10 is provided in an outer case 9 made of a light-shielding resin for accommodating the light emitting element 5 and the light receiving element 6 and used as a light passage surface, and light from the light emitting surface 1a to the light receiving surface 2a is provided. Had formed a passage. Note that FIG.
Reference numeral 11 denotes a condenser lens made of a translucent resin.

[0005]

Generally, in order to improve the resolution of the transmissive photointerrupter, a light passage with good positional accuracy is required. This positional accuracy can be determined by the width of the surface and the positional accuracy of the surface which are the passages of light.

In the conventional light-emitting element 5 and light-receiving element 6, the secondary molding process with the light-shielding resin and the housing of the outer case 9 made of the light-shielding resin allow the passage of light through the window 8 and the slit 10. Forming a surface. For this reason,
The number of manufacturing steps and the number of constituent members increase, resulting in high cost.

Further, these light emitting element 5 and light receiving element 6
In the transmissive photointerrupter using the above, the light emitting and receiving elements 5 and 6 are not properly positioned during the secondary molding process, and when the light receiving and emitting elements 5 and 6 are housed in the outer case 9, the positional deviation of the light receiving and emitting elements 5 and 6 and the slits 10 are prevented. May be misaligned. Therefore, a transmissive photointerrupter may have poor positional accuracy in the passage of light.

In view of the above, the present invention provides an optical element that can obtain a light passage having a high positional accuracy, and a transmissive optical coupling device that uses the optical element and has a high resolution.

[0009]

According to a first aspect of the present invention, there is provided a translucent resin body 28 formed by encapsulating optical chips 21 and 25 with a translucent resin. On the front surface of the body 28, the chip surface 21 of the optical chip 21, 25
a, 25a and light-passing portions 30 and 31 formed into a curved surface capable of collecting light, and adjacent to or having a step with the light-passing portions 30 and 31 and in front of the chip surfaces 21a and 25a. Inclined part 3 inclined at an angle of 30 to 60 degrees
2, 33 are formed.

According to a second aspect of the present invention, an optical element 20 having an optical chip 21 for light emission and an optical element 24 having an optical chip 25 for receiving light are optically arranged with a passage T of an object to be detected therebetween. They are arranged so as to face each other so as to be coupled.

[0011]

In the means for solving the problems according to claims 1 and 2, the light emitted from the light-emitting optical chip 21 travels through the light-transmitting resin body 28, and the light reaching the light-passing portion 30 on the light-emitting side is transmitted. The object to be detected jumps out of the flexible resin body 28 onto the passage T. Further, the light reaching the inclined portion 32 is totally reflected by the refractive indexes of the air and the translucent resin body 28 and does not jump out of the translucent resin body 28 onto the passage T of the object to be detected.

Of the light emitted from the light-transmitting portion 30 on the light-emitting side, the light reaching the light-transmitting portion 31 on the light-receiving side enters the transparent resin body 28 and the chip surface of the light-receiving optical chip 25. 25a is reached. The light reaching the inclined portion 33 is refracted and travels away from the chip surface 25a. This allows
On the passage T of the object to be detected, the light passing portion 30 on the light emitting side
A light passing path H from the light receiving portion to the light passing portion 31 on the light receiving side is formed.

[0013]

<First Embodiment> As shown in FIGS. 1 and 2, in a light emitting element 20 which is an optical element of a first embodiment of the present invention, a light emitting optical chip (hereinafter, light emitting chip) 21 is a mounting lead. It is bonded to the terminal 22 and internally connected to the connection lead terminal 23. Then, these are molded with a translucent resin such as an epoxy resin.

Similarly to the light emitting element 20, the light receiving element 24 also has an optical chip (hereinafter, light receiving chip) 25 for light reception bonded to a mounting lead terminal 26 and internally connected to a connection lead terminal 27. Then, these are molded with a translucent resin such as an epoxy resin.

The light emitting chip 21 is an infrared light emitting diode using gallium arsenide (GaAs), and the light receiving chip 25 is a phototransistor using silicon (Si).

Transmissive optical coupling device (photo interrupter)
Is a light emitting element 20 and a light receiving element 24 as shown in FIGS.
Are integrally opposed to each other with the translucent resin body 28 sandwiching the passage T of the object to be detected.

The transparent resin body 28 is a light emitting chip 21.
The light-emitting side and the light-receiving side are integrally molded so that the chip surfaces 21a, 25a of the light-receiving chip 25 face each other and are formed in a concave shape in a front view.

Further, each chip surface 21 of the transparent resin body 28
A recess is formed in the center of the facing surface located in front of a, 25a. This recess is formed on each of the chip surfaces 21a and 25a.
Light passing side 3 and light receiving side 3 formed in parallel with a
0, 31 and 30 degrees to 60 degrees forward of the chip surfaces 21a, 25a formed on both sides of the light passage portions 30, 31.
The inclined portions 32 and 33 are inclined at an angle of degrees.

In the above structure, when the inclined portions 32 and 33 have an angle of about 45 degrees with respect to the chips 21 and 25, as shown in FIG. 4, the light emitted from the light emitting chip 21 is transparent. Proceed inside the resin body 28. Of these, the light that has reached the light passage portion 30 on the light emitting side jumps out of the transparent resin body 28 as it is onto the passage T of the object to be detected in the air. Also,
The light that has reached the inclined portion 32 is totally reflected by the refractive indexes of the air and the transparent resin body 28 and does not jump out of the transparent resin body 28 onto the passage T of the object to be detected.

Of the light emitted from the light-transmitting portion 30 on the light-emitting side, the light reaching the light-transmitting portion 31 on the light-receiving side enters the light-transmitting resin body 28 and is directly received on the chip surface 25a of the light-receiving chip 25. To reach. However, the light reaching the inclined portion 33 is refracted when it enters the light-transmitting resin body 28, travels away from the chip surface 25a, and does not reach the chip surface 25a.

As a result, as shown in FIG. 5, on the passage T of the object to be detected, a passage H of light from the light passage portion 30 on the light emitting side to the light passage portion 31 on the light receiving side is formed. become. At this time, when the object to be detected shields the light passage H, the amount of light received on the chip surface 25a of the light receiving chip 25 disappears and the output from the light receiving chip 25 changes, whereby the object to be detected is detected.

It should be noted that, due to scattering in the transparent resin body 28 and fine irregularities on the surface of the transparent resin body 28, light other than the light passage H is slightly reflected on the chip surface 25a of the light receiving chip 25. Although it may arrive, the amount of light has little influence on the detection of the object to be detected.

As described above, the light which adversely affects the detection of the object to be detected is totally reflected or refracted by the inclined portions 32 and 33 of the light-transmissive resin body 28, so that the light receiving chip 25 is obtained.
Of the light from the light emitting side light passing portion 30 to the light receiving side light passing portion 31 is formed. The object to be detected can be detected by blocking the light passage H.

Therefore, the light emitting element 20 and the light receiving element 2
In 4, there is no need for a secondary molding step or an outer case for forming a light passage surface, which is required in the related art, and the number of manufacturing steps and components can be reduced, resulting in cost reduction.

Further, in the transmissive photo interrupter, the position accuracy of the passage H of the light that determines the detection position accuracy of the object to be detected is determined by the translucent resin body 28 for integrally disposing the light emitting side and the light receiving side to face each other. Depends only on the shape of the mold used to mold. Therefore, the light passage H with high positional accuracy can be formed, and the resolution is improved.

<Second Embodiment> As shown in FIG. 6, the transmissive photointerrupter of the second embodiment has a curved surface on which the light passing portions 40 and 41 of the light emitting element 20 and the light receiving element 24 are projected forward and can be condensed. It is said to be a state.

As a result, the chip surface 2 of the light emitting chip 21
The light emitted from 1a and reaching the light passing portion 40 on the light emitting side is condensed and guided to the light passage H, and when reaching the light passing portion 41 on the light receiving side, it is condensed and received by the light receiving chip 25. Is efficiently guided to the chip surface 25a. The other configurations are the same as those in the first embodiment.

<Third Embodiment> As shown in FIG. 7, the transmission type photointerrupter of the third embodiment has a shape in which the light passing portions 50 and 51 of the light emitting element 20 and the light receiving element 24 are curved in an arc shape in the vertical direction. And is formed to have a step behind the inclined portions 32 and 33.

As a result, as in the second embodiment, the light emitted from the chip surface 21a of the light emitting chip 21 is condensed and efficiently guided to the chip surface 25a of the light receiving chip 25. The other configurations are the same as those in the first embodiment.

The present invention is not limited to the above embodiments, and it goes without saying that many modifications and changes can be made to the above embodiments within the scope of the present invention.

For example, not only the light emitting element 20 and the light receiving element 24 of the first, second and third embodiments are integrally opposed to each other and used for the transmission type photo interrupter, but also as the light emitting element 20 or the light receiving element 24. It may be used alone.

[0032]

As is clear from the above description, according to the first aspect of the present invention, only the light reaching the light passage portion is used, and the light reaching the inclined portion is not used. The light transmitting surface can be formed only by the primary molding process using the resin. Therefore, there is no need for a secondary molding step or an outer case for forming a light passage surface as in the conventional case, and the manufacturing steps and constituent members can be reduced,
Cost reduction.

According to the second aspect, the positional accuracy of the light passage depends on only the shape of the mold for molding the light-transmissive resin body for integrally disposing the light emitting side and the light receiving side. A light passage with good positional accuracy can be formed, and the resolution is improved.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a transmissive photo interrupter according to a first embodiment of the present invention.

FIG. 2 is a perspective view of a light emitting element and a light receiving element.

FIG. 3 is a perspective view of a transmissive photo interrupter.

FIG. 4 is a diagram showing a traveling direction of light from a light emitting chip in a transmissive photo interrupter.

FIG. 5 is a diagram showing a light passage path in a transmissive photo interrupter.

FIG. 6 is a perspective view of essential parts of a transmissive photo interrupter according to a second embodiment.

FIG. 7 is a perspective view of a main part of a transmissive photo interrupter according to a third embodiment.

FIG. 8 is a cross-sectional view of a conventional transmissive photointerrupter.

FIG. 9 is a cross-sectional view of another conventional transmissive photointerrupter.

[Explanation of symbols]

 20 light emitting element 21 light emitting chip 21a light emitting chip surface 24 light receiving element 25 light receiving chip 25a light receiving chip surface 28 translucent resin body 30,31 light passing portion 32,33 inclined portion

Claims (2)

[Claims] 1. A translucent resin body obtained by encapsulating an optical chip with a translucent resin, wherein the front surface of the translucent resin body is parallel to the chip surface of the optical chip or can be condensed. And a sloped portion that is adjacent to or has a step and is inclined forward at an angle of 30 to 60 degrees with respect to the chip surface. Optical element to do. 2. The optical element according to claim 1, which is provided with an optical chip for emitting light, and the optical element, which is provided with an optical chip for receiving light.
A transmission type optical coupling device, characterized in that the optical element described above is integrally opposed to each other so as to be optically coupled to each other with a passage of an object to be detected interposed therebetween, and the presence or absence of the object to be detected is detected without contact. .