JPH10126343A - Optical communication equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain high speed data transfer in the optical communication according to the infrared ray data association or the like. SOLUTION: This equipment is provided with a light-emitting element 1 that emits a light to other equipment, a light-receiving element 2 that receives a light from the other equipment, an optical means 6 that is provided to each front side of the light-emitting element 1 and the light-receiving element 2 and limits coherence of respective lights, and a driver means 7 that drives a light- emitting diode according to a signal and reads the output of the light-receiving element. Preferably the optical means 6 is composed of polarization plates whose polarization optical axes are orthogonal to each other. Thus, full duplex communication is conducted different from a conventional half-duplex communication system, an since the polarization plates orthogonal to each other restricts the vibrating direction of the light, lights having vibrating direction crossing with each other are delivered to the object light-receiving element, without being interfered with each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical communication device suitable for a device for transmitting and receiving optical signals.

[0002]

2. Description of the Related Art In recent years, the infrared data association (IrDA) has been taking the lead in performing short-distance optical communication in portable equipment and office equipment, thereby improving the portability and convenience of the equipment, and improving wireless communication between the equipment. Control and information sharing have come to be performed. In a device having such an optical communication function, a light emitting element and a light receiving element are connected to a device, for example, a portable type such as an electronic notebook, as described in page 251 of the June 1995 issue of Transistor Technology Magazine by CQ Publishing Company. It is arranged on the back of an information device, and the device is arranged and used so as to exchange data with another device, for example, a light emitting element or a light receiving element of an electronic notebook or a printer.

[0003] The optical communication system in this case is ASK (Amplit).
ude Shift Keying), SIR (Serial Infrared In)
terfared Interface), FIR (Fast Infrared Int)
The above-mentioned association has indicated four schemes, ie, the PPM (Pulse Position Moduration) and PPM (Pulse Position Modulation), but all of them are serial transmissions, and the transmission speed is 4.0 Mbps even at the highest PPM.

[0004]

However, these devices require an increase in the amount of transmitted data and a need for bidirectional communication. For example, when an optical communication device is incorporated in the back of each device of an electronic notebook and a personal computer to transfer large-capacity data such as image data, low-speed serial transfer (half-duplex communication) may be required. It takes a long time to communicate, and it is easy for data errors and communication errors to occur due to changes in the environment during long communication. Failure to respond, both mobile and customer frustrated.

[0005]

SUMMARY OF THE INVENTION In view of the above, the present invention has been made because it has been found that this is due to the fact that spatial transmission is performed by a simple light beam. Light-emitting element provided to emit light, a light-receiving element for receiving light from another device, and optical means provided on the front of each of the light-emitting element and the light-receiving element for limiting the coherence of each other's light And driver means for driving the light emitting diode in accordance with a signal to read the output of the light receiving element. Preferably, the optical means comprises polarizing plates whose polarization axes are orthogonal to each other.

[0006]

FIG. 1 is a cross-sectional view of an optical communication apparatus according to an embodiment of the present invention. Here, the device 9 is, for example, a portable information device such as an electronic organizer or a multimedia-compatible mobile phone, an office device such as a personal computer or a printer, and is not limited to the infrared data association (IrDA) or the like. Although it does not exist, it has specifications for performing optical communication between devices, especially short-distance optical communication within 1 m. In such a device 9, the optical communication device is connected to, for example, a computer bus via an interface such as a USART and an I / O port. Although FIG. 1 illustrates an example in which the optical communication device is provided so as to be built in the vicinity of a corner of a device 9 having a liquid crystal display or a CPU board, the present invention is not limited to this. It may be housed in a communication unit connected to the main body by a cord.

In FIG. 1, reference numeral 1 denotes a light-emitting element provided to emit light toward another device 90, which is exemplified by a chip. Such a light emitting device 1 includes GaN blue-violet (emission wavelength 430 nm), GaN blue (emission wavelength 4
50 nm), SiC blue (emission wavelength 470 nm), Ga
P green (emission wavelength 555 nm), GaP yellow green (emission wavelength 565 nm), GaAsPonGaP yellow (emission wavelength 585 nm), AlGaInP yellow (emission wavelength 590 n
m), GaAsPonGaP orange (emission wavelength 610 n
m), AlGaInP orange (emission wavelength 620 nm), G
aAsPonGaP red (emission wavelength 635 nm), Ga
AlAs red (emission wavelength 660 nm), GaP red (emission wavelength 695 nm), GaAlAs infrared color (emission wavelength 8
30 nm), GaAlAs infrared color (emission wavelength 850 n)
m), GaAlAs infrared color (emission wavelength 880 nm), G
aAs infrared rays (emission wavelength: 945 nm) can be selected. In this case, if there is a standard such as the above-mentioned IrDA, it is preferable to select so as to comply with it.

Reference numeral 2 denotes a light-receiving element for receiving light from another device 90, which is disposed close to the light-emitting element 1 and includes silicon P
It consists of an IN photodiode. The light emitting element 1 and the light receiving element 2 are made of a light-transmitting resin in which a chip mounted on the submount 3 is wired by wire bonding or the like, and has a lens shape corresponding to the direction of the optical path. 4 are integrally molded. Integrating with a resin in this way is preferable because the transmission direction of light is matched and the entire communication light beam is easily narrowed. However, the present invention is not limited to this. It may be arranged and fixed on a base 5 such as a printed circuit board or a top surface of an integrated circuit. Further, it is preferable that a dye is mixed in the resin 4 so as to prevent mixing of light having an unnecessary wavelength.

Reference numeral 6 denotes an optical means provided on the front surface of each of the light emitting element 1 and the light receiving element 2 for limiting the coherence of light between the light emitting element 1 and the light receiving element 2. A diffraction grating or a hologram can be used. Of polarizing plates orthogonal to each other. This means that it can be easily attached to and detached from the outer wall of the device 9 by inserting or the like, and even if the polarization axis is not known, the axis orientation can be confirmed by rotating the two by overlapping them. Similar optical means 60 must be provided, but because they are relatively easily available.
In addition, the optical unit 6 may be in the form of a lens or the like, and may also be used to protect the device 9 from dust.

Reference numeral 7 denotes a driver for driving the light emitting diode 1 in accordance with a signal and reading the output of the light receiving element 2, and is composed of an integrated circuit element mounted on a lead frame 8. The driver means 7 includes, for example, a driver for supplying a current to the light-emitting element 1 and a reading circuit for reading out the output from the light-receiving element 2 (the light-receiving element in this example has a light-receiving element 20 for obtaining its output signal). With an amplifier that amplifies the output by applying a bias to the filter).
If necessary, a modulation / demodulation circuit comprising a functional I / O port for driving the light emitting element 1 according to a signal and reproducing a signal from the output of the light receiving element 2 connected to the reading circuit is included. The above-described modulation / demodulation circuit may be used to drive these light-emitting elements and light-receiving elements, or signal processing may be performed, an I / O port of a device may be used, or a one-chip CPU may be used.

With such a configuration, full duplex communication can be performed instead of the conventional half duplex communication, and the polarizing plates orthogonal to each other regulate the vibration direction of light. The held light is transmitted to a target light receiving element without interference.

[0012]

As described above, in the optical communication apparatus, there is no interference even if the optical communication apparatuses of both devices are turned on at the same time, so that full-duplex communication can be performed and the communication time can be shortened. it can.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an optical communication device according to an embodiment of the present invention incorporated in a part of equipment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Light emitting element 2 Light receiving element 3 Submount 4 Resin 5 Base 6 Optical means 7 Driver means 8 Lead frame 9 Equipment 90 Other equipment

Claims (1)

[Claims] 1. A light emitting device provided to emit light toward another device, a light receiving device for receiving light from another device, and a light emitting device provided on a front surface of each of the light emitting device and the light receiving device. An optical communication device comprising: an optical unit that limits coherence of light from each other; and a driver unit that drives the light emitting diode according to a signal and reads an output of the light receiving element.