JPS60117834A - Optical space transmitter - Google Patents

Abstract

PURPOSE:To attain ease of positioning at light projecting side and photodetecting side at a near range and also to extend the transmission range with less power consumption by using >= one light emitting element having a narrow directivity and >= one light emitting element having a wide directivity. CONSTITUTION:A signal 1 is modulated by a modulation section 2 at the light projecting side, a modulated signal is amplified by a drive section 3 and a near infrared light 5 corresponding to the modulation sinal is irradiated from a light emitting section 4. The light 5 enters a photodetector 6 at the photodetecting side, where the light is converted into an electrical signal, and it is amplified by an amplifier section 7 and demodulated by a demodulating section 8 and then a signal 9 is outputted. LEDs are used as light emitting elements in the constitution of the light emitting section 4, and plural number, e.g., four LEDs 10, 11, 12 and 13 are mounted on a plane of a board. The LEDs 10, 13 among them have a narrow directivity and the LEDs 11, 12 have a wide directivity. Since the wide directivity is obtained at the short range and the long transmission range is obtained regardless of the narrow directivity, this system is advantageous.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an optical space transmission device that can be used to transmit analog or digital signals.

Conventional configurations and their problems In general, when transmitting analog or digital signals indoors, they are easy to move, are not subject to electromagnetic interference, and are
Optical space transmission equipment is advantageous in that there are no legal regulations.

The light emitting section of a conventional optical space transmission device is composed of only light emitting elements with narrow directivity or only light emitting elements with wide directivity.

Unfortunately, the directivity of the light emitting section of the optical space transmission device was either narrow as shown in FIG. 1 or wide as shown in FIG. Since the optical space transmission device is easy to move, the positional relationship between the transmitting side optical space transmission device and the receiving side optical space transmission device varies in various ways. There is a problem in that it is difficult to align the light transmitting side and the light receiving side even at short distances. Furthermore, in the case of a wide directivity as shown in FIG. 2, the transmission distance is short, and if the transmission distance is to be increased, the optical puff must be made larger, resulting in increased power consumption.

OBJECTS OF THE INVENTION The present invention obviates such conventional problems.
It is an object of the present invention to provide an optical space transmission device that allows easy positioning of a light transmitting side and a light receiving side over a short distance, consumes little power, and has a long transmission distance.

Structure of the invention - The optical space transmission device of the present invention uses a light emitting element with narrow directivity.
The light emitting section is constructed using at least two light emitting elements with wide directivity, and can be easily aligned at short distances, and can also be used at long distances.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. A block diagram of the optical space transmission device is shown in FIG.

First, on the light transmitting side, signal 1 is converted to ASK, FSK by modulator 2.
.

PSK modulated, the modulated signal is amplified by the driving section 3, and the light emitting section 4 emits near-infrared light 5 corresponding to the modulated signal. Next, on the light receiving side, the near-infrared light 6 enters the light receiving element 6, is converted into an electrical signal, and is amplified by the amplifying section 7. The amplified signal is demodulated by a demodulator 8 and a signal 9 is output.

The light emitting section 4 has a structure using LEDs as light emitting elements, and as shown in FIG.
12 and 13 are placed on the same plane of the substrate 14. Among these, L HD I 0°13 has narrow directivity as shown in FIG. 5, and LEDll, 12 has wide directivity as shown in FIG.

This result 1. The directivity of the light emitting section 4 consisting of four lCDs is as shown in FIG. Therefore, the directivity is wide at short distances, and the directivity is narrow at long distances, but a long transmission distance is advantageous.

Effects of the Invention As described above, the present invention constitutes a light emitting section by combining one or more light emitting elements with narrow directivity and - or more light emitting elements with wide directivity, so that alignment is difficult at short distances. It is easy to use, allows the equipment to be moved freely, and although positioning is required over long distances, it can reach a long distance with low optical power and is very useful for reducing power consumption.

[Brief explanation of the drawing]

Figure 1 is a narrow directional characteristic diagram of a conventional light emitting unit, Figure 2 is a wide directional characteristic diagram of a conventional light emitting unit, Figure 3 is a block diagram of the optical space transmission device of the present invention, and Figure 4 is a diagram of the present invention. FIG. 5 is a perspective view showing the configuration of the light emitting part of the optical space transmission device; FIG. 5 is a directional characteristic diagram of an LED with narrow directivity among the LEDs used in the present invention; FIG.
The figure is a directional characteristic diagram of an LED with a wide directivity among the LEDs used in the present invention, and FIG. 7 is a directional characteristic diagram of the light emitting part of the optical space transmission device of the present invention. 10.13... Light emitting element with narrow directivity, 11°12... Light emitting element with wide directivity. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 5
Figure 0 Foil 6 Figure O. Japanese map 7 O''

Claims (1)

[Claims] An optical space transmission device characterized in that a light emitting section is constructed using at least one light emitting element with narrow directivity and one or more light emitting elements with wide directivity.