JP2005327880A - Connector structure for high speed/large capacity signal connection - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a connector for connecting high speed/large capacity signal connection by the rays of light when the speed of signal transfer is limited through electricity. <P>SOLUTION: This connector structure transfers a signal from a first electric circuit to a second electric circuit, by attachably/detachably fitting a first base mounted with a light emitting element for emitting a signal from the first electric circuit as an optical signal, and a second base mounted with a light receiving element for receiving the optical signal from the light emitting element, and for transmitting it to the second electric circuit. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a connector that realizes high-speed and large-capacity transmission connection, a mass storage device incorporating the connector, a personal computer, a moving image display device, and the like.

  In recent years, the processing speed of CPUs (central processing units) exceeding Giga and the capacity of storage devices have been increasing. Mass storage devices exceeding 100 megabytes and 1 gigabyte such as memory stick (registered trademark), compact flash (registered trademark), SD memory card (registered trademark), compact disc (CD) drive, digital video disc (DVD) drive, etc. Devices have been commercialized (Non-patent Document 1). However, the signal communication speed between these devices and personal computers, car navigation systems, moving image display devices, and the like is several tens of megabits per second at the maximum, and it takes time to exchange data. Although a multi-channel approach is also conceivable, the number of channels is limited due to the trend toward smaller and thinner devices. In the future, when further large-capacity memory devices are developed, this low communication speed becomes a problem. This is due to noise in the electrical connection portion, electromagnetic radiation, and the like, and with the conventional simple connection method, transmission at 100 megabits per second was difficult.

On the other hand, various high-speed electrical connectors have been developed, but they are coaxial and have a bulky structure. In addition, the design of the ground becomes important, and the number of pins increases. In addition, high processing accuracy is required, and gold-plated SUS, brass, or the like is used, resulting in high costs. Considering the trend toward miniaturization and cost reduction of these devices, it will be difficult to apply high-speed compatible electrical connectors.
Transistor Technology CQ Publisher January 2002 Issue

 An object of the present invention is to propose a connector for connecting a high-speed, large-capacity signal connection portion with light so as to avoid the above-described problems.

 As a result of intensive studies, the present inventor has found that there is almost no influence of noise and electromagnetic radiation by using a connector with a built-in light receiving and emitting element that can perform signal connection with light, and has completed the present invention.

That is, the present invention includes a first base on which a light-emitting element that emits light from a signal from the first electric circuit as an optical signal in order to transmit a signal from the first electric circuit to the second electric circuit; In this connector structure, a second base on which a light receiving element that receives an optical signal from the light emitting element and transmits it to the second electric circuit is detachably fitted.
As a result, high-speed signals exceeding 10 GHz can be transferred between the two electric circuits.

It is preferable that the first or second base is simultaneously provided with an electrical connection portion for supplying power to the light emitting element or the light receiving element.
The base may be package-shaped or plate-shaped.

 By using the connector according to the present invention, since there is no electrical contact in the connector portion, high-speed and large-capacity signals can be communicated between various devices.

Hereinafter, the present invention will be described in detail. Here, a connector using an epoxy molding material will be described as an example, but it is of course possible to use other sintered bodies such as resins and ceramics.
As shown in FIG. 1, an epoxy resin composition is used to mold into a hollow package. At this time, the molded body 1 is provided with a space in which the light emitting element and the light receiving element can be mounted. Further, the lead frame 2 may be incorporated and integrally formed, such as QFP (quad flat package) or DIP (dual in package) (FIG. 1 (a)). Next, electrical wiring (not shown) for driving the light emitting / receiving element is applied to the molded body. For this, various methods such as a lift-off method, a surface roughening method and a plating method are conceivable. Next, each of the light emitting diode chip 8 and the surface light receiving element chip 9 as an optical element was solder-mounted one by one and electrically connected to the lead frame by wire bonding (FIG. 1 (b)). Thereafter, the dip portion was embedded with a transparent epoxy resin 10 and cured by ultraviolet irradiation.

 In this way, a connector capable of optical connection was created (FIG. 1 (c)). Lead frame from each molded body is connected by soldering on FR-4 glass epoxy printed wiring board including electric circuit that drives light emitting / receiving element, molded body 14 with circuit processing 13 etc. Fixed (Figure 2). In addition to the connector shape of FIG. 1, a member having a protrusion on the outer periphery is prepared separately, and the connectors of FIG. A connector structure for transmitting signals between light emitting and receiving elements can be realized. The state of the fitting is shown in a sectional view in FIG. Here, an alignment pin 32 and a receiving hole 33 are provided.

  Next, FIG. 3 shows an example in which a part of the electrical connection port of the memory board is optically connected. This partially uses a form in which a memory board on which a chip such as a memory chip conventionally used is mounted is fixed to a slit as a connector on another board. In FIG. 3, a light receiving or light emitting element 35 is provided at a location exposed from the slit of the memory board 24 in which the chip 23 such as an electric circuit or a memory chip is mounted and the electric terminal 34 is arranged, and is pasted to the height of the electric terminal row. They are optically connected by an optical waveguide film 36 in which 45 ° mirrors are formed at both ends. At this time, on the slit side, a light emitting or light receiving element is embedded in the inner surface of the slit, or the light emitting or light receiving element provided at any position on the slit side with an optical waveguide film having 45 ° mirrors formed at both ends. Connecting. Specifically, a through hole is provided in the memory board, and the light receiving element or the light emitting element 35 is fixed so that the light receiving part or the light emitting part covers the through hole. An optical waveguide film 36 (indicated by a dotted line because it is the back side in FIG. 3) is attached to the opposite surface to which the light receiving element or the light emitting element is fixed. One end of the waveguide film is applied to the through hole, and an optical path is formed from the light receiving element or the light emitting element to the optical waveguide by being bent at a right angle by a 45 ° mirror formed at one end. Further, an optical path is formed toward a light emitting element or a light receiving element provided on the inner surface of the slit by a 45 ° mirror on the other end side of the optical waveguide film or toward a 45 ° mirror of another optical waveguide guided to the light emitting element. . In order to prevent the board from easily coming out of the slit, a commonly used detachable lever (not shown) may be provided. .

As another form, in order to optically connect a part of the electrical connection port of the memory board, the above-described molded body with a built-in light emitting / receiving element may be fixed by soldering. At this time, a recess corresponding to the size of the molded body is formed on the slit recess side of the connector structure.
In another form, remove the upper layer of a part of the multilayer printed wiring board of the memory board, or apply printed wiring board processing to a previously removed shape, and mount the light emitting element and light receiving element directly on the resulting dip, wire There is also a method of bonding

  In the optical connection by the fitting structure, the alignment accuracy of the light receiving element and the light emitting element is important. Generally, the light receiving diameter of a light receiving element capable of high-speed response is about 100 μm to 500 μm, and the light emitting element is about 10 μm. Another connector structure for this purpose is shown in FIG. In this structure, the substrate in which the light receiving element 5 and the light emitting element 4 are embedded is fitted. Here, it is preferable to provide a fitting pin 21 for alignment and a fitting hole 22 as a guide for receiving it. This pin may be embedded from the beginning as a molded body, or a hole may be formed later and the pin embedded therein. FIG. 5 (a) shows a die that is pushed in and fitted in the vertical direction, and FIG. 5 (b) is a die that is pushed in and fitted in the horizontal direction.

  In particular, when a light emitting element having a large divergence angle such as a light emitting diode is used, if the light receiving elements are arranged on the array, the light is received by the adjacent light receiving elements, which may cause crosstalk. In such a case, in order to avoid this crosstalk, it is preferable to form a light shielding thin film 31 as a light shielding mask on the surface of the sealing resin as shown in FIG.

  In the embodiments described so far, the dip portion is sealed with resin. However, a form in which a transparent lid is provided on the front surface of the light emitting / receiving element, such as a hollow package without sealing, may be used. At this time, as shown in FIG. 7, a lid 41 on which a lens 51 for condensing light is formed may be used. Furthermore, an optical waveguide may be used instead of a lens.

  A lead frame having a thickness of 0.2 mm was placed on the mold, and a resin package was molded using the epoxy resin composition. The epoxy resin composition used was TM-250G manufactured by Mitsui Chemicals. At this time, the size was 5 mm × 5 mm and the molded body had a thickness of 2 mm. At the same time, a dip having a size of 2 mm × 2 mm and a depth of 1 mm was provided near the center of the molded body for mounting an optical element or the like. Next, the entire lead frame including the through hole is plated in the order of nickel plating (5 μm) and gold plating (0.3 μm), and the external terminals and the lead frame are placed on the through holes previously formed in the lead frame. By cutting, an individual connector molded body was obtained. Create two similar shaped bodies. At this time, in order to align the optical connection and to mechanically fit the connectors together, a convex shape with a diameter of 1 mm and a height of 1 mm on one side, a diameter of 1.5 mm and a depth of 1.5 mm on the other side. By forming the groove by molding, positioning can be performed with an alignment accuracy of ± 0.25 mm. When the light receiving element has a light receiving diameter of 300 μm, sufficient optical connection is possible with this accuracy.

Next, one red light emitting diode chip and one surface light receiving element chip were solder-mounted as optical elements, and the lead frame was electrically connected by wire bonding. Thereafter, the dip portion was embedded with a transparent epoxy resin and cured by irradiation with ultraviolet rays at 30 mW / cm ² for 10 minutes. Polishing was performed to flatten the surface and to bring out the connector surface (molded resin surface) on the surface. In this way, a connector capable of optical connection was created. The lead frame coming out of each connector was soldered onto a printed wiring board made of FR-4 glass epoxy including a circuit for driving the light emitting / receiving element. By fitting the concave and convex portions that serve as the guides for the two connectors, sending a modulation signal of 200 megabits per second to the light emitting diode and transmitting it to the other connector side with light, the receiving element on the receiving side opens a good eye Pattern was observed.

The figure which shows an example of the connector manufacturing process of this invention. The figure which shows an example of the connector structure of this invention. The figure which shows an example of the connector structure of this invention. The figure which shows the fitting part cross section of the connector structure of this invention. The figure which shows the detailed cross section of the connector structure of this invention. The figure which shows the detailed cross section of the connector structure of this invention. The figure which shows an example of the connector structure mounted with the micro lens of this invention

Explanation of symbols

1: molded body, 2: lead frame, 3: electrical wiring,
4: Light emitting element, 5: Light receiving element, 7: Printed wiring board,
8: Light emitting diode chip, 9: Surface light receiving element chip, 10: Epoxy resin, 11: Electrical connection part,
21: mating pin 22: mating hole 23: chip 24: memory board 31: light shielding thin film,
41: Lid, 51: Lens,

Claims (2)

In order to transmit a signal from the first electric circuit to the second electric circuit, a first base on which a light emitting element that emits light as a signal from the first electric circuit is mounted; A connector structure, wherein a second base on which a light receiving element for receiving an optical signal and transmitting it to a second electric circuit is detachably fitted. 2. The connector structure according to claim 1, wherein the first or second substrate is simultaneously provided with an electrical connection for supplying power to the light emitting element or the light receiving element.

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