JPH10209490A - Reflective optical coupling device - Google Patents

Abstract

(57) [Problem] To prevent light from a light emitting element from being incident on a light receiving element when there is no object to be detected, and to increase the light collection efficiency. A light-emitting side light-transmitting member 1 in which a light-emitting element 10 is sealed.
The primary molded body 11, the light-transmitting primary molded body 13 on which the light-receiving element 12 is sealed, and the light-emitting side provided in the positioning recess 18 on the front surface, which is the light-emitting surface of the light-emitting primary molded body 11. The lens 14 and the light receiving side lens 15 installed in the positioning recess 19 on the front surface which is the light incident surface of the light receiving side primary molded body 13
Contacting the fixed portions 14a, 15a of the lenses 14, 15, the two primary molded bodies 11, 13 and the lenses 14, 1
And a light-shielding secondary molded body 16 integrally sealing 5.
Voids for changing the refractive index are formed between the lenses and the primary molded bodies.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reflection type optical coupling device for detecting the presence or absence of an object without contact.

[0002]

2. Description of the Related Art Some reflection-type optical coupling devices are provided with a lens for efficiently condensing light. First, FIG. 8 shows a conventional reflection type optical coupling device with a lens. In this reflection type optical coupling device with a lens, the light emitting element 3 and the light receiving element 4 which are separately mounted on the lead frame 1 and internally connected by the gold wire 2 are respectively sealed with independent translucent resins, and the primary The molded bodies 5a and 5b are formed, and these primary molded bodies 5a and 5b are juxtaposed and integrally sealed with a light-shielding resin to form a secondary molded body 6. Further, a pair of lenses 7a and 7b are connected to the lensless reflection type optical coupling device.
And a transparent lens case 8 having

FIG. 9 shows another conventional reflection type optical coupling device with a lens. In this reflection type optical coupling device with a lens,
The light emitting element 3 and the light receiving element 4 which are separately mounted on the lead frame 1 and internally connected by the gold wires 2 are respectively sealed with independent translucent resins to form primary molded bodies 5a and 5b, and at the same time, Convex lenses 9a, 9b corresponding to the respective elements 3, 4 are formed on the front surfaces of the primary molded bodies 5a, 5b.
The secondary moldings 6 are formed by juxtaposing the secondary moldings 5a and 5b and covering portions of the primary moldings 5a and 5b excluding the front surface with a light-shielding resin.
Is formed.

[0004]

However, in the former reflection type optical coupling device, since the lens case is attached to the lensless reflection type optical coupling device, light emitted from the light emitting element is reflected by the lens case and received. May be incident on the element,
There is a problem that some detection output appears even when there is no object to be detected.

Further, in the latter reflection type optical coupling device, since the lens is directly molded on the primary molded body, only one refracting surface can be formed, and the light cannot be efficiently collected.

In view of the above-mentioned problems, the present invention solves the problem that some detection output appears even when there is no object to be detected, and can improve the light collection efficiency with a lens. It is an object of the present invention to provide a type optical coupling device.

[0007]

The object of the present invention is to provide a light-emitting-side translucent primary molded article in which a light-emitting element is sealed,
A light-receiving-side light-transmitting primary molded article in which a light-receiving element is sealed; a light-emitting side lens provided on the front surface of the light-emitting-side light-transmitting primary molded article; And a light-shielding secondary molded body that is in contact with a fixed portion of each lens and that integrally seals both primary molded bodies and each lens. The secondary molded body and the light-receiving side translucent primary molded body are juxtaposed.

Further, a gap for changing the refractive index is formed between each primary molded body and each lens.

According to this, since each primary molded body and each lens are integrated by the secondary molded body independently of each other, the light emitting side and the light receiving side are completely independent, and when there is no object to be detected. Thus, it is possible to prevent light from the light emitting element from being incident on the light receiving element via the lens. Furthermore, the interface between the primary molded body and the lens serves as a light refraction surface, so that light can be efficiently collected. In particular, by forming the air gap, the number of refracting surfaces of light is increased, and the light collection efficiency is further improved.

Also, instead of forming a void, the refractive index of the primary molded body and the refractive index of the lens are made different from each other.
Each may be made of a different material to substitute for the gap.

The light-transmitting primary molded body and the light-transmitting primary molded body each have a recess for positioning a lens. According to this, since the lens can be accurately positioned with respect to each element, the light from the light emitting element and the light reflected by the object can be effectively collected, and the light collection efficiency can be further improved. Can be.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A reflection type optical coupling device according to an embodiment of the present invention will be described with reference to the drawings. As shown in FIG.
The reflection type optical coupling device includes a light emitting side translucent primary molded body 11 sealing a light emitting element 10, a light receiving side translucent primary molded body 13 sealing a light receiving element 12, and a light emitting side primary molded body. A light-emitting side lens 14 installed on the front surface, which is a light-emitting surface of the molded body 11,
The light receiving side lens 15 installed on the front surface, which is the light incident surface of the light receiving side primary molded body 13, and the two primary molded bodies 11, 13 and each lens contacting the fixed portions 14a, 15a of the lenses 14, 15, respectively. And a light-shielding secondary molded body 16 in which 14 and 15 are integrally sealed. In the figure, 17 is the light emitting element 1
This is a light shielding wall provided so that light does not directly enter the light receiving element 12 from 0.

In order to position the lenses 14 and 15 on the front surface of each of the primary molded bodies 11 and 13,
Depressions 18 and 19, which are curved in accordance with the curvature of the lens 15, respectively, are further formed.
13, gaps 20 and 21 for changing the refractive index are formed. The recesses 18 and 19 have a circular or rectangular shape, and the width is smaller than the lenses 14 and 15.

Such a reflection type optical coupling device is manufactured as follows. First, the light emitting element 10 and the light receiving element 12 are mounted on a pair of lead frames 22a on one side arranged on the same plane by die bonding.
3 internally connects to a pair of lead frames 22b on the other side. Next, the light receiving and emitting sides are separately sealed with a translucent resin such as an epoxy resin to form a light emitting side primary molded body 11 and a light receiving side primary molded body 13. At this time, recesses 18 and 19 curved inward are formed on the front surfaces of the light emitting side primary molded body 11 and the light receiving side primary molded body 13, respectively, and the central portions thereof are further deeply recessed, so that they are used for voids. Dent.

Then, lenses 14 and 15 formed separately from the primary molded bodies 11 and 13 using the same translucent resin are placed in the recesses 18 and 19. Thereby, the lens 1
4 and 15 are accurately positioned with respect to the primary molded bodies 11 and 13, and the lenses 14 and 15 and the primary molded body 1
Voids 20 and 21 are formed between the front surfaces of the first and the first 13.

Next, in order to arrange the primary molded bodies 11 and 13 on the light emitting side and the light receiving side at a predetermined interval, the primary molded bodies 11 and 13 are sealed with a light-shielding resin such as a light-shielding epoxy resin. . At the same time, the fixed portions 14a, 15a on both sides of each of the lenses 14, 15 except for the light emitting surface on the front surface of the light emitting side lens 14 or the light incident surface on the front surface of the light receiving side lens 15, are sealed with a light shielding resin. Thus, each primary compact 1
The secondary molding 16 is formed by performing secondary molding for integrally sealing the lenses 1 and 13 and the lenses 14 and 15 to complete a reflection type optical coupling device with a lens.

According to the structure of the above-mentioned reflection type optical coupling device,
The light emitted from the light emitting element 10 is first transmitted to the primary molded body 11.
Is refracted at the interface between the gap 20 and the lens 1.
The light is refracted at the interface with the light source 4, and further refracted when exiting the lens 14, and is emitted to the outside. When the light reflected by the object enters, the light is refracted in the reverse order and reaches the light receiving element 12.

Therefore, each time light is refracted on a plurality of refraction surfaces, the light is condensed, and the light can be emitted without being diffused. Even when light is incident, the light can be efficiently condensed.
Light can be used effectively.

Therefore, it is not necessary to mount a transparent lens case as in the prior art, so that the dimension in the height direction can be reduced, and light emitted from the light emitting side is reflected by the transparent lens case and enters the light receiving side. Is gone,
When no object is detected, no output appears and a small and highly reliable reflective optical coupling device with little leakage current is obtained.

Here, the light condensing effect in the reflection type optical coupling device of the present embodiment will be described using an optical simulation. As shown in FIG. 2, (a) a conventional reflection type optical coupling device with a lens case attached thereto, (b) a conventional reflection type optical coupling device with a lens, and (c) reflection type light in which no gap is formed in the present embodiment. Optical simulation was performed for each model of the coupling device and (d) the reflection type optical coupling device of the present embodiment. The results are shown in FIGS.

According to this, it can be confirmed that the light of the present embodiment is condensed because there are a plurality of light refraction surfaces as shown in FIG. On the other hand, in the conventional one, FIGS.
It can be seen that light is emitted without being condensed as shown in FIG. Although the lenses 14 and 15 are provided, the gaps 20 and 2 are provided.
In the case where 1 is not formed, light is diffused as shown in FIG. This is because the lenses 14, 15 and the primary molded body 11,
Since the refractive indexes of the lenses 13 and 13 are almost the same as 1.51 and 1.54, respectively, the lenses 14 and 15 and the primary molded bodies 11 and 1
This is because the light is hardly refracted at the interface with No. 3 and does not converge.

Therefore, if the materials of the lenses 14 and 15 are changed to a light-transmitting resin or glass different from the light-transmitting resin forming the primary molded bodies 11 and 13, the refractive index of the lenses 14 and 15 and the primary molding are changed. The refractive indices of the bodies 11 and 13 can be different. Therefore, even when no gap is provided, the number of refraction surfaces can be two, and the lenses 14 and 15 can be formed.
If the shape of is appropriately designed, the light collection efficiency can be increased. Moreover, since the lenses 14 and 15 on the light receiving and emitting sides are provided independently of each other, light from the light emitting element 10 does not enter the light receiving element 12 when there is no object to be detected as in the related art.

FIG. 7 shows a reflection type optical coupling device according to another embodiment. In this case, the front faces of the primary molded bodies 11 and 13 are flattened, and the semicylindrical lenses 14 and 15 are fixed to the front faces of the primary molded bodies 11 and 13 with a transparent adhesive 25. That is, the adhesive 25 forms a layer between the lenses 14 and 15 and the primary molded bodies 11 and 13 and substitutes for a gap. Other configurations and operational effects are the same as those shown in FIG. In this case, since the thickness of the lenses 14 and 15 can be reduced, the size of the apparatus can be reduced.

It should be noted that the present invention is not limited to the above embodiment, and it goes without saying that many modifications and changes can be made to the above embodiment within the scope of the present invention. For example, the gap may be filled with a light-transmitting fluid different from the light-transmitting resin forming the light-transmitting fluid or the primary molded body for the purpose of changing the refractive index or bonding the lens. Further, the lens may be provided only on one of the light emitting side and the light receiving side.

Further, the light emitting element and the light receiving element need not be juxtaposed on the same plane, but may be a reflection type optical coupling device having a structure in which the light emitting element and the light receiving element are arranged to be inclined in the direction in which they face each other.

[0026]

As is apparent from the above description, according to the present invention, the light emitting side translucent primary molded body, the light emitting side lens, the light receiving side translucent primary molded body, and the light receiving side lens are independently formed. Since it is arranged and integrated by secondary molding,
The light-emitting side and the light-receiving side are completely independent, and can prevent light from the light-emitting element from entering the light-receiving element via the lens when there is no object to be detected.

In addition, the interface between the primary molded body and the lens serves as a light refraction surface, so that light can be efficiently collected. In particular, by forming a gap therebetween, the number of light refraction surfaces increases, and the light collection efficiency can be further improved. Therefore, it is possible to provide a reflective optical coupling device having high reliability and high light collection efficiency.

Further, since the concave for positioning the lens is formed in the primary molded body, the lens can be accurately positioned with respect to the element, and the light collection efficiency can be further improved.

[Brief description of the drawings]

FIGS. 1A and 1B show a reflection type optical coupling device according to an embodiment of the present invention, wherein FIG. 1A is a plan view and FIG.

FIG. 2 is a model diagram for optical simulation;
(A) is a reflection type optical coupling device with a conventional lens case, (b) is a conventional reflection type optical coupling device with a lens,
(C) is a reflection type optical coupling device in which no gap is formed in the present embodiment, and (d) is a reflection type optical coupling device of the present embodiment.

FIG. 3 is a diagram showing an optical simulation result in a conventional reflection type optical coupling device to which a lens case is attached.

FIG. 4 is a diagram showing an optical simulation result in a conventional reflection type optical coupling device with a lens.

FIG. 5 is a diagram showing an optical simulation result in a reflection type optical coupling device in which no air gap is formed in the present embodiment.

FIG. 6 is a diagram showing an optical simulation result in the reflection type optical coupling device of the present embodiment.

FIG. 7 is a sectional view of a reflection type optical coupling device according to another embodiment.

8A and 8B show a conventional reflection-type optical coupling device, wherein FIG. 8A is a plan view and FIG.

9A and 9B show another conventional reflection-type optical coupling device, wherein FIG. 9A is a plan view and FIG.

[Explanation of symbols]

 Reference Signs List 10 light emitting element 11 light emitting side primary molded body 12 light receiving element 13 light receiving side primary molded body 14 light emitting side lens 15 light receiving side lens 16 secondary molded body 18, 19 recess 20, 21 gap

Claims (4)

[Claims] 1. A light-emitting side translucent primary molded article in which a light-emitting element is sealed, a light-receiving side translucent primary molded article in which a light-receiving element is sealed, and a light-emitting side translucent primary molded article. The light emitting side lens installed on the front surface, the light receiving side lens installed on the front surface of the light receiving side translucent primary molded body, and both primary molded bodies and each lens are integrated by contacting the fixed part of each lens. A light-shielding secondary molded body, which is electrically sealed, wherein the light-emitting side translucent primary molded body and the light-receiving side translucent primary molded body are juxtaposed. . 2. A light-emitting side light-transmitting primary molded article in which a light-emitting element is sealed, a light-receiving side light-transmitting primary molded article in which a light-receiving element is sealed, and a light-emitting side light-transmitting primary molded article. The light emitting side lens installed on the front surface, the light receiving side lens installed on the front surface of the light receiving side translucent primary molded body, and both primary molded bodies and each lens are integrated by contacting the fixed part of each lens. A reflective optical coupling device, comprising: a light-shielding secondary molded body which is sealed in a sealed manner; and a gap for changing the refractive index is formed between each primary molded body and each lens. 3. The light-transmitting light-transmitting primary molded body and the light-receiving side light-transmitting primary molded body each have a recess formed therein for positioning a lens.
The reflection type optical coupling device as described in the above. 4. A lens according to claim 1, wherein the refractive index of the primary molded body is different from the refractive index of the lens.
The reflection type optical coupling device according to any one of the above.