JPH0265182A - Semiconductor photocoupler - Google Patents

Abstract

PURPOSE:To enhance general characteristic, same phase noise characteristic, to simplify assembling steps, and to rationalize it by providing a groove in which an optical fiber is inserted on the enclosure of each element. CONSTITUTION:Both ends of an optical fiber 13 formed beforehand on the basis of an interval between both a LED 11 and a phototransistor PTr 12 are inserted into grooves 22 formed at both the LED 11 and the phototransistor PTr 12, and the insertion parts are adhesively secured with transparent resin 14. Thus, it can prevent optical axes from deviating at the time of manufacture, transmission efficiency from decreasing due to the deviation of the optical axes at the time of ageing change, and an air layer between elements and the optical fiber is eliminated. The LED, the PTr coupled by the fiber 13 are associated with a resin-molded shielding case 15, covered with a resin cover 16, and then sealed with black epoxy resin 17 thereby to obtain a photocoupler.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) The present invention relates to a semiconductor optical coupling device, and is particularly used for signal transmission between circuits that require insulation, and is used to reduce common mode noise (common mode noise). - Noise) characteristics.

(Prior Art) The configuration of a semiconductor optical coupling device (hereinafter abbreviated as an optical coupling device) that has been widely used in the past is shown in a cross-sectional view in FIG. As shown in FIG. 7, the light emitting diode pellet 101 and the phototransistor pellet 102 are connected to the respective leads 103a of the lead frame.

103b with a conductive adhesive 104, and connect each electrode and lead with Au thin wires 105a, 105b to form a light emitting element 106 (hereinafter abbreviated as LED) and a phototransistor 107. The LHD 106 and the phototransistor 107 are arranged with their respective pellets 101 and 102 facing each other, and after forming an optical path between the LED and the phototransistor with a transparent silicone capping resin 108, a light-shielding epoxy resin is used to block external light. An optical coupling element is constructed by applying resin 109 coating.

The optical coupling device with the above structure has the disadvantage that the distance between the LHD 106 and the phototransistor 107 is usually 1 m or less, which increases the capacitance between input and output, and that noise entering the LED side is easily transmitted to the phototransistor side. there were.

A solution to the above problem is to widen the distance between the LED and the phototransistor, but since the light intensity decreases exponentially with distance, as shown in Figure 8,
The individually sealed LED unit 116 and phototransistor 117 are fitted to both ends of, for example, a white light-reflecting tube body 110 that serves as an optical path, and these are inserted into a black case 111, a back cover 111a made of plastic is attached, and There is a structure in which external light is shielded by sealing with black epoxy resin 112.

The optical coupling device described above with reference to FIG. 8 still has the following problems.

(1) Since the optical path has a hollow structure, the transmission efficiency is significantly inferior.

(IT) The number of structural parts is large, and the unit price of each part is expensive.

1' City) Manufacturing costs are high due to complicated assembly.

Furthermore, the output form is only phototransistor output, and it is difficult to create SCR, TRIAC, IC output, etc.
There is also the problem that the user side has difficulty in designing the circuit of the set.

Next, in the perspective view partially shown in FIG. 9(a), and (
As shown in the cross-sectional view seen from above in b), a single LED 1
Fiber 1 is connected to the optical path between 26 and phototransistor 127.
20, and after forming an optical path by bonding one end of the fiber 120 to the LED unit 126 and the other end to the phototransistor 127, the fiber 120 is placed in a case 121, and liquid epoxy resin 122 is filled in the case 121. There is a structure designed to block external light.

(Problem to be Solved by the Invention) In the optical coupling element using a fiber in the optical path, L
Since the fiber installed in the optical path between the ED unit and the phototransistor is in contact with the epoxy resin, a portion of the light passing through the fiber is absorbed by the resin, resulting in a serious problem in which the optical coupling between the input and output is weakened. There's a problem.

SUMMARY OF THE INVENTION An object of the present invention is to provide an improved structure in view of the problems of the conventional optical coupling device described above.

[Structure of the invention]

(Means for Solving the Problems) A semiconductor optical coupling device of the first invention includes a light emitting element and a light receiving element that are arranged facing each other at a predetermined interval, and optical axes of the two elements are coupled and fixed to each other to form an optical path. optical fiber,
A light-shielding case that houses both the elements and the optical fiber, and a sealing resin that seals the light-shielding case, and the light-emitting element and the light-receiving element include respective optical axes on opposing surfaces, and the optical fiber is inserted through the light-emitting element and the light-receiving element. The semiconductor optical coupling device according to the second aspect of the invention is characterized by having a groove or a recess with a width of an optical fiber that connects and fixes optical axes to each other to form an optical path; a light-shielding case that houses both of the elements and the optical fiber; and a seal that seals each of the markings enclosed in the light-shielding case integrally with the light-shielding case. It is characterized in that it comprises a resin, and the optical fiber faces the sealing resin with a gap interposed therebetween.

(Function) This invention includes an optical axis between an LED and a phototransistor, and couples them with an optical fiber, and also provides a groove in the envelope of each element to allow the optical fiber to pass through, thereby improving both coupling characteristics and common-mode noise characteristics. This provides an excellent optical coupling device.

Furthermore, the shape of each element is changed from the conventional ball lens type to the grooved type, thereby simplifying and rationalizing the assembly process.

Furthermore, a gap is provided around the optical fiber so that it faces the sealing resin, thereby further improving the optical coupling characteristics.

(Embodiments) Hereinafter, embodiments of the first invention will be described with reference to FIGS. 1 to 3.

In a first embodiment according to the first invention shown in a cross-sectional view in FIG. 1, an LED II and a phototransistor 12 are shown in FIG.
As shown in the front view as seen from the optical axis direction in FIG. 2, and as shown in the side view in FIG. It is being Further, this groove 22 may be a recessed portion (not shown).

In FIG. 2(a), a chip 24 is attached to a chip bed 23a by a lead 23, and an electrical connection is made between the electrode and the lead by a bonding wire 25. LED configured as described above 11. Both ends of an optical fiber 13, which has been prepared in advance based on the spacing between the two, are inserted into grooves 22 provided in both individual phototransistors 12, and the inserted portions are adhesively fixed with a transparent resin 14. has been done. This prevents a decrease in transmission efficiency due to optical axis misalignment during manufacturing and over time, and eliminates the air layer between each unit and the optical fiber, resulting in a decrease in the refractive index between them. Since they are almost equal, there is an advantage that there is no scattering or reflection of light, and furthermore, it is possible to omit treatment of the end face of the optical fiber. Next, the LED/phototransistor system connected by the optical fiber is installed in a resin-molded light-shielding case 15, covered with a resin-molded cover 16, and then sealed with a black epoxy resin 17 to turn on the light. A coupling element is obtained.

In the above process, the optical fiber 13 is fixed after the LED 11 and the phototransistor U are inserted into the cover 16, and the effect is the same even if the cover 16 is used instead of a jig type.

Next, the second embodiment according to the first invention shown in FIG.
The cover 16 used in the above embodiment is not used, and the entire body is sealed with a light-shielding epoxy resin 31, but in this case, the interface between the two units 11 and 12 and the optical fiber 13 is already covered with transparent resin. Filled with layer 14 and filled with epoxy resin 3
1 will not infiltrate and adversely affect the transmission characteristics. In addition, in the past, transparent resin had poor adhesion at the interface with the lead frame such as leads and had problems with moisture resistance, but the structure of this embodiment, which is entirely resin-sealed, prevents outside air from entering from the interface. In particular, it has the advantage of reducing moisture intrusion and significantly improving moisture resistance.

Next, in the first embodiment according to the second invention shown in FIG. 4, FIG. 4(a) is a perspective view for explaining the configuration of the main part, and FIG. As shown in the partial cross-sectional perspective view of the product housed in the case, there are double grooves 34 on the opposing surfaces of the resin sealing body 33 of the LED 31 and the phototransistor 32.
is formed. This double groove 34 consists of a deep groove 34a and a shallow groove 34b formed coaxially, and the deep groove 34
The shallow groove 34b has a larger diameter than the deep groove 34a, and the end of the cylindrical body 35 installed coaxially with the optical fiber 13 is inserted through the shallow groove 34b. What can I say? Further, the cylindrical body 35 is connected to the optical fiber 13.
LED 31 is formed slightly shorter than LED 31.
The grooves are formed so as to correspond to the sum of the differences in depth of the respective grooves provided on the opposing surfaces of the phototransistor 32.

The main components configured as shown in FIG. 4(a) above are housed in a case 36 as shown in FIG. 4(b), and a liquid sealing resin 37 is injected and after hardening. It is formed by applying a lid. With the above configuration, the optical fiber 13 and the sealing resin 37 are configured to be in non-contact.

Next, in the second embodiment of the second invention shown in FIG. 5, as shown in FIG. The optical fiber 13 including the optical axis of each element between opposing surfaces and the cylindrical body 35 surrounding this optical fiber are assembled inside a case 46, and the optical fiber 13 and the cylindrical body 35 are placed above the cylindrical body 35.
The front cover 46a of the case and the gfi 46b of the case are sandwiched from below.
Optical fiber supports 47a, 47b and cylindrical supports 48a, 48b are provided in contact with the case 46, and a liquid sealing resin 37 is injected into the case 46 and hardened.

Next, a third embodiment of the second invention shown in FIG. 6 is a combination of the features of the first and second embodiments of the second invention. That is, as shown in FIG.
ED 31. Each resin sealing body 33 of the phototransistor
Double grooves 34 are formed on the opposing surfaces of. This double groove 34 is a deep groove 34a and a shallow groove 34b formed coaxially.
The deep groove 34a is inserted at the end of the optical fiber 13, and the shallow groove 34b has a larger diameter than the deep groove 34a, and is a coaxial part of the cylindrical body 35 installed coaxially with the optical fiber 13. A portion of each diameter is provided through which the end portion is inserted. Further, the cylindrical body 35 is formed to be slightly shorter than the optical fiber 13, and the difference in length is equal to the sum of the difference in depth in the grooves provided on the opposing surfaces of the LED 31 and the phototransistor 32. are formed to correspond. Therefore, LED 31 and phototransistor 32
The optical fiber 13 is inserted into each deep groove of each groove 34, 34 on the opposing surface of the
Insert both ends of the optical fiber 1 into the optical axis between the opposing surfaces.
3 is arranged, and both ends of the cylindrical body 35 are inserted into each shallow groove 34b of the groove, and the optical fiber 13 and the cylindrical body 35 are moved up and down so that the cylindrical body 35 is disposed coaxially with the optical fiber 13. Optical fiber supports 47a and 47b are in contact with the front cover 46a of the sandwich case and the back side M46b of the case from the direction, and have their longitudinal ends inserted into the grooves 46 for orientation.
, cylindrical bodies 48a and 48b are assembled and placed in a case 46 with one lid attached. Next, after attaching the other lid, a liquid sealing resin is injected and hardened to form an optical coupling element.

〔Effect of the invention〕

According to the present invention, with the structure of a conventional optocoupler.

The problem of poor coupling characteristics and common-mode noise characteristics was overcome by using optical fibers, which made both of the above characteristics excellent. Furthermore, by changing the shape of the LED and phototransistor from the conventional ball lens type to a grooved type, the assembly process can be simplified and streamlined. Furthermore, as shown in FIG. 3, the moisture resistance of the product can be improved by creating a structure that does not use the IA lid of the case.

Next, especially in the structure of the second invention in which the optical fiber is covered with a cylindrical body, the optical coupling is significantly improved because the resin does not come into contact with the optical fiber. Further, by providing optical fiber supports 47a, 47b and cylindrical body supports 48a, 48b for positioning and fixing the optical fiber and the cylindrical body to the LED and phototransistor, it is possible to create a space between the fiber and the cylindrical body. A gap is provided to completely prevent contact,
Transfer characteristics are improved.

Furthermore, the structure in which supports are provided on the case side and the back cover has the same effect as the structure in which grooves are provided on the opposing surfaces of both elements. Next, products with the above-mentioned structural features that combine the provision of a support and the provision of grooves have the same remarkable effects as above, and are particularly stable and easy to manufacture. make it easier.

[Brief explanation of the drawing]

1 to 6 relate to the present invention, FIG. 1 is a sectional view for explaining a first embodiment of the first invention, and FIG. 2 is an external view of each element of the LED and phototransistor shown in FIG. 1. FIG. 3A is a front view, FIG. 3B is a side view, and FIG. 3 is a sectional view showing a second embodiment of the first invention. FIG. 4 is a diagram (a) for explaining the first embodiment of the second invention.
) is a perspective view, (b) is a perspective view partially shown in cross section, (a) is a cross-sectional view for explaining the second embodiment of the second invention, and (b) is (a ) along line AA, No. 6
The figure is a perspective view showing a part in cross section for explaining the third embodiment of the second invention, and FIGS. 7 to 9 are related to the conventional example, and FIG. 7 is a sectional view of one example. FIG. 8 is a cross-sectional view of another example, and FIG. 9 is a perspective view showing still another example. (a) is a partially sectional perspective view, and (b) is a cross-sectional view. 11, 31... LED 12, 32... Phototransistor 13... Optical fiber 14... Transparent resin 15, 36. 46... Case 47a, 47b... Optical fiber support body 48a, 4
8b...Cylindrical body support 34...Grooves 17, 24...Sealing resin agent Patent attorney Ogo Norifudai' α: Nasoah 7d 2d ゛ Bonding wiper, %: Teff. Figure 3 M: 7-person J7: Keicho' 2^ii Fat diagram (2 of A) +8 and ko 1, +B6: FIF-ζ) t-yoshi]'t'ko 1, 15-5th Figure (Ime 1) 2 ÷: Egokire Thirty Fat Figure 3 Figure (Seal 2) Figure j03a, 103-t, : Rit'〆O3a,
To! ;ft: Au-mount Bj4f07: Fukanhihiuuresis 7 1Oq Shirou, 7t goki = - Wang 5S shaku 170 invasion re-order resistance ÷ 1 1Oro: LED /DB: = /υ Corne, ki! Liv II 1'l'ffi
7th cm3+: Ln20 thickness A; 1F=, tt”y: F

Claims (2)

[Claims] (1) A light-emitting element and a light-receiving element arranged facing each other at a predetermined interval, an optical fiber that connects and fixes the optical axes of the two elements to each other to form an optical path, and a light-shielding device in which both the elements and the optical fiber are internally installed. a case, and a sealing resin for sealing the light-shielding case, and the light-emitting element and the light-receiving element each have a groove or a recess on their mating surfaces that includes each optical axis and has a width through which the optical fiber is inserted. Semiconductor optocoupler. (2) A light-emitting element and a light-receiving element arranged opposite to each other at a predetermined interval, an optical fiber that connects and fixes the optical axes of the two elements to each other to form an optical path, and a light-shielding device that houses the elements and the optical fiber. A case, and a sealing resin sealed in the light-shielding case to integrally seal each of them with the light-shielding case, and the optical fiber is opposed to the sealing resin with a gap interposed therebetween. Semiconductor optical coupling device.