JPH04243331A - Optical wireless transmitter - Google Patents

Abstract

PURPOSE:To improve the transmission efficiency by dividing a space in which a receiver is considered to move into some spaces, selecting one or several spaces in the vicinity of the receiver and sending an infrared ray/optical signal to them. CONSTITUTION:When an infrared ray signal is sent from a receiver 7 to a transmitter, plural light receiving sections 4 of the transmitter receive the signal respectively and give the strength to a comparator circuit 5 respectively. The comparator circuit 5 compares the signal strength to discriminate a space in which the receiver 7 is in existence thereby controlling a distribution changeover circuit 2. On the other hand, a sound signal is given to an input terminal 1 and sent to any light receiving section 3 in a direction of the space in the vicinity of the receiver 7 selected by the distribution changeover circuit 2 depending on the information of the comparator circuit 5. Then the sent infrared ray signal is sent only to spaces in the vicinity of the plural receivers 7. Thus, the transmission quality in the case of using plural optical wireless transmitters in a same space is improved.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmitter for an optical wireless transmission device that transmits video signals, audio signals, and other analog or digital signals by using light such as infrared rays.

0002

[Prior Art] In recent years, wireless remote controllers that use infrared rays for devices have become widespread, and wireless headphones, etc.
Some optical space transmission of V signals has also been put into practical use.

An embodiment of a conventional transmitter for optical spatial transmission of video signals will be described below with reference to the drawings.

FIG. 4 is a block diagram showing the configuration of a conventional optical space transmission transmitter, and FIG. 5 is a diagram schematically showing the mechanism of the conventional optical space transmission transmitter.

Now, consider the case where a video signal is applied to the video signal input terminal 11 (FIG. 4) and is output as an infrared optical signal by the video signal optical space transmission transmitter. The modulation circuit 12 uses the input video signal as a modulation signal and converts the carrier wave into an FM signal.
Modulate. The drive circuit 13 drives the light emitting section 14 (infrared light emitting diode) using the FM modulated wave generated by the modulation circuit 12, and outputs it as an infrared light signal. When used in a situation where the relative position of the receiver to the transmitter changes, it is possible to increase the number of light emitting parts as shown in Figure 4 to transmit infrared optical signals to all the spaces in which the receiver is expected to move. Delivery is done. (FIG. 5) shows an outline of the mechanism of this transmitter for optical space transmission.

[0006]

[Problems to be Solved by the Invention] In the case of an optical wireless transmission transmitter having the configuration as shown in FIG. The received power of the receiver is very small compared to the power consumed by the receiver, and the transmission efficiency is very poor. Furthermore, when optical wireless transmission devices that utilize the same principle exist in the same space, it is difficult to completely separate the transmitted optical signals from each other, resulting in a problem in that the quality of transmission is impaired.

Therefore, the present invention improves transmission efficiency by dividing the space in which the receiver is expected to move into several parts, and selecting one or several spaces near the receiver to deliver the infrared optical signal. This is intended to improve transmission quality when multiple optical wireless transmission devices are used in the same space.

[0008]

[Means for Solving the Problems] In order to achieve this object, the optical wireless transmission transmitter of the present invention includes a position detection unit that detects the position of the receiver, and a position detection unit that detects the position of the receiver. A distribution switching circuit is provided that distributes and switches the input electrical signal based on the information of The space is arranged so as to be divided into appropriate spatial angles, and the selected light emitting section is configured to transmit the transmission optical signal only to the space near the receiver.

[0009]

[Operation] With this configuration, the optical wireless transmission transmitter of the present invention divides the space in which the receiver is expected to move into several spaces, selects one or several spaces near the receiver, and transmits the infrared optical signal. It is possible to improve transmission efficiency and improve transmission quality when a plurality of optical wireless transmission devices are used in the same space.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

(FIG. 1) is a block diagram showing the configuration of an optical wireless transmission transmitter according to an embodiment of the present invention, and (FIG. 2) shows an outline of the mechanism of an optical wireless transmission transmitter according to an embodiment of the present invention. This is a diagram. (FIG. 3) is a diagram illustrating a case where a plurality of sets of optical wireless transmission transmitters according to an embodiment of the present invention are used in the same space. In the figure, 1 is an input terminal, 2 is a distribution switching circuit, 3 is a plurality of light emitting units installed, 4 is a light receiving unit provided in a pair with the light emitting unit 3, and 5 is a signal from each light receiving unit 4. This is a comparison circuit that compares the strength (level). 6a and 6b are optical wireless transmission transmitters having the configuration shown in FIG. 1, and 7a and 7b are speakers incorporating an optical wireless transmission receiver and an audio amplifier.

Now, the case of using this optical wireless transmission transmitter will be explained with reference to (FIG. 1), (FIG. 2), and (FIG. 3). First, of the two sets of optical wireless transmission devices (FIG. 3), the set 6a and 7a will be explained. First, an infrared signal is transmitted from the receiver 7a to the transmitter 6a. This infrared signal is received by a plurality of light receiving sections 4 of the optical wireless transmission transmitter 6a shown in FIG. Comparison circuit 5
compares the intensity signals, determines the space in which the receiver 7a exists, and controls the distribution switching circuit 2. On the other hand, an audio signal is connected to the input terminal 1, and this audio signal is sent to one of the light emitting sections 3 in the spatial direction near the receiver 7a selected by the distribution switching circuit 2 based on the information from the comparison circuit 5. The transmitted infrared signal is transmitted only to the space near the receiver 7a. The number of spaces near the receiver 7a is not limited to one, and it may be desirable to have a plurality of spaces depending on the conditions of use.

In this way, when using the optical wireless transmission devices 6a and 7a, the second optical transmission device 7b is located outside the space near 7a, which is limited by the spatial resolution of the optical wireless transmission transmitter determined by the number of light emitting parts. By installing the optical wireless transmission receiver 6b and 7b, a plurality of optical wireless transmission devices can be used simultaneously without mutual interference by adding second optical wireless transmission devices 6b and 7b.

[0014]

As described above, according to the present invention, the space in which the receiver is expected to move is divided into several spaces, and one or several spaces near the receiver are selected to deliver an infrared optical signal. As a result, transmission efficiency can be improved and transmission quality can be improved when a plurality of optical wireless transmission devices are used in the same space, and the practical effects thereof are extremely large.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the configuration of an optical wireless transmission transmitter according to an embodiment of the present invention.

FIG. 2 is a schematic diagram of the mechanism of an optical wireless transmission transmitter according to an embodiment of the present invention.

[Fig. 3] An image representation diagram when multiple sets of optical wireless transmission transmitters according to an embodiment of the present invention are used in the same space.

[Figure 4] Block diagram of the configuration of a conventional optical wireless transmission transmitter

FIG. 5 is a schematic diagram of the mechanism of a conventional optical wireless transmission transmitter.

[Explanation of symbols]

2 Distribution switching circuit 3 Light emitting part 4 Light receiving section 5 Comparison circuit

Claims (2)

[Claims] 1. An input terminal to which an input electrical signal is applied, a distribution switching circuit that distributes and switches the input electrical signal, a plurality of light emitting units that converts the output electrical signal of the distribution switching circuit into a transmission optical signal, and a transmission and a position detection unit that detects the position of the optical signal receiver, and the light emitting unit is arranged so as to divide the space around the receiver into appropriate spatial angles, and has appropriate directivity. The optical wireless transmission is characterized in that the output of the distribution switching circuit is switched according to the receiver position information obtained by the position detection section, so that the transmitted optical signal is transmitted only to the space near the receiver. vessel. 2. The optical device according to claim 1, wherein the position detection unit is constituted by a plurality of light receiving units that receive infrared signals from a receiver and a comparison circuit that compares the light reception intensities of the light receiving units. Wireless transmission transmitter.