JPH01181245A - Light transmitter for optical radio paging - Google Patents

Abstract

PURPOSE:To reduce power consumption regardless of a long signal transmission range by lighting each light emitting device in a light transmitter in time division. CONSTITUTION:Infrared rays LEDs 13a-13d are provided around a cylindrical package 12 in a light transmitter 11. An input data is composed of plural times of repetition of sets of blocks A-D. The contents of the blocks A-D are entirely the same. The block A turns on three LEDs 13a. The blocks B-D light respectively LEDs 13b-13d composed of respective three LEDs. Thus, the LEDs 13a-13d are lighted sequentially in time division at every prescribed time by the blocks A-D, the processing is repeated to transmit the data. Thus, zones I-IV of a room are scanned sequentially by the infrared-ray.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a light transmitting device for optical wireless paging, and more specifically, to a light transmitting device useful in an optical wireless paging system that emits light in a plurality of different directions. The present invention relates to a light transmitting device for optical wireless paging.

(Prior Art) There are various examples of systems that transmit data by spatially propagating infrared light indoors. FIG. 7 shows an example. The system shown in the figure functions as follows. That is, a host computer 1 connects an indoor satellite (fixed station) 3 via a cluster controller 2.
is controlled, and data is emitted from the satellite 3 using infrared light. The emitted infrared light is reflected by the ceiling, walls, etc. in the room, and is received as indirect light by the terminals 4 provided at various positions in the room. As a result, data is transmitted from the host computer 1 to the terminal 4.

FIG. 8 shows another example of indoor data transmission using infrared light. In this example, a satellite main body 7 connected to a network is provided indoors. The satellite main body 7 is connected by a cable 8 to a satellite head 9 attached to the ceiling. An office terminal 10 that transmits and receives data to and from the satellite head 9 using infrared light is installed indoors. In each example, direct wave propagation of infrared light is used to transmit and receive data.

(Problems to be Solved by the Invention) In the conventional example shown in FIG. 7, indirect light obtained by reflecting direct light from the satellite 3 evenly on the ceiling and walls is used for data transmission. Therefore, there are almost no restrictions on the indoor installation position of the terminal 4 that receives the indirect light. However, since it uses indirect light,
The infrared light source of the satellite 3 needs to be of a high output type and consume a large amount of power.

Further, in the conventional example shown in FIG. 8, direct infrared light is used for data transmission. Therefore, a lower output type infrared light source than the one shown in FIG. 6 can be used as the infrared light source. However, office terminal l
The location where O is installed is subject to restrictions. For example, if a plurality of office terminals 10 are distributed in a large room, a plurality of satellite heads 9 must be installed on the ceiling accordingly.

Furthermore, in both cases of FIG. 7 and FIG. 8, the infrared light is radiated from the satellite 3 and the satellite head 9 over a wide range, regardless of the arrangement positions of the terminal 4 and the office terminal 10. There is. Therefore, it is inevitable that power consumption becomes large.

The present invention has been made in view of the above, and its purpose is to:
An object of the present invention is to provide a light transmitter for optical wireless paging that can reliably perform long-distance communication with low power consumption. Light in which a current whose value changes depending on the data to be transmitted is passed through multiple light emitters, and each light emitter emits light whose intensity changes depending on the data in different directions. The wireless paging light transmitting device is configured to include time division means for time-divisionally flowing a current whose value changes according to the data to each of the plurality of light emitters.

(Function) The time division means causes a current in accordance with the data to be transmitted to flow through each of the plurality of light emitters in a time division manner. Thereby, each light emitting device emits light in different directions in accordance with the above data in a time-division manner. At a certain time,
All of the plurality of light emitters do not emit light at the same time. Therefore, power consumption is lower than when all the light emitters emit light at the same time.

(Example) FIGS. 1 and 2 are plan and side views of a room in which a light transmitting device according to an embodiment of the present invention is attached to the ceiling of the room in an actual state of use, and FIG. shows an enlarged view of the transmitter. That is, the light transmitting device 11 is attached to the ceiling C of the room, as shown in FIG. The light transmitting device 1
1 is a cylindrical container 12 as shown in FIGS. 1 and 3.
Infrared light LEDs 13a to 13d are provided around the .

Three infrared LEDs 1''3a to 13d are provided each. The three LEDs 13a are connected in series (see Fig. 5) and are turned on at the same time.LE
The same applies to each of the three D13b to D13d. The infrared light from the three LEDs 13a covers zone I of the room, as shown in FIG. L.E.
Similarly, the infrared light from each of the three D13b to D13d covers zones (1) to (2).

FIG. 4 is a timing chart showing the relationship between the input data applied to the light transmitting device 11 and the on/off states of each of the LEDs 13a to 13d. The above input data is a set of blocks A to D, and the set is repeated a plurality of times. The contents of those blocks A to D are all the same.

Block A lights up three LEDs 13a.

Three LEDs 13b to 13d each according to blocks B-D
are lit respectively. As a result, as shown in the figure, the LEDs 13a to 13d are sequentially turned on for a certain period of time in blocks A to D in a time-division manner, and this is repeated to transmit data. As a result, as shown in FIG. 1, zones 1 to 3 of the room are sequentially scanned by infrared light. For example, a light receiver 15 as a transmission target
As shown in FIG. 1, when the light is in zone (2), data is transmitted to the light receiver 15 when the light transmitter 13c is turned on. In the photoreceiver 15, I of the received data
If the D data matches its own ID data, for example, a buzzer sounds, and if the received data includes a message, the message is displayed on the display.

FIG. 5 shows an example of a circuit for realizing time-divisionally turning on and off the LEDs 13a to 13d as described above. An input terminal 21 to which input data shown in FIG. 4 is applied is connected to amplifiers 23a to 23d via parallel switches 22a to 22d. Those amplifiers 23a to 23d are connected to each of the three infrared light LEDs 13a.
~13d is connected to a power supply with a voltage of +V.

The amplifier 23a is configured such that when input data is applied via the switch 22a, a current having a value corresponding to the input data flows from the power supply into the amplifier 23a via the LED 13a.

The amplifiers 23b to 23d are also configured in substantially the same manner.

The switches 22a to 22d are turned on and off by a timing clock generator 26 and a switching control voltage generator 27 connected in series to the input terminal 21. That is, the input data applied to the input terminal 21 is applied to the timing clock generation section 26. The timing clock generation section 26 generates a timing clock based on the input data and applies it to the next stage switching control voltage generation section 27. The switching control voltage generation section 27 generates switching control voltages Ea to Ed shown in FIG. 6 based on the applied timing clock and applies them to the switches 22a to 22d.

As a result, the switches 22a to 22d
Each voltage Ea-Ed is turned on only during level 1 in the order of a to 22d, and this is repeated. For example, when the switch 22a is turned on, the infrared LED 13a emits light, and the infrared light propagates data to zone l in FIG. By sequentially turning on the switches 22b to 22d, the infrared light LED
13b to 13d sequentially emit light, and data is sequentially propagated to zones (1) to (2).

In the above embodiment, all of the infrared light LEDs 13a to 13d do not emit light at the same time;
It is divided into two blocks, and the LEDs of each block are made to emit light in a time-division manner.

In this way, infrared light L E D 13 a to 13 d
Since 1/4 of the LEDs are emitted sequentially, the infrared light can be propagated further and the service area can be extended to a longer distance with the same power consumption as when all LEDs 13a to 13d are emitted at the same time. can do. Therefore, the number of satellite stations can also be reduced. Conversely, if the service area covers the same distance as when all LEDs are turned on at the same time, the power consumption would be 17%.
It becomes 4.

In the above embodiment, the infrared LED was divided into four blocks. However, the number of blocks to be divided is not limited to four, and may be any number greater than or equal to two.

Furthermore, although the number of LEDs in each block is three in the above embodiment, it can be any other number.

Furthermore, it is also possible to simultaneously light up the LEDs of two or more blocks among the plurality of divided blocks. For example, L
The ED can be divided into eight blocks, and the LEDs in two of the eight blocks can be lit at the same time.

(Effects of the Invention) According to the present invention, each light emitting device in the light transmitting device is turned on in a time-sharing manner, so that power consumption can be reduced in relation to the signal transmission distance.

[Brief explanation of the drawing]

1 and 2 are plan and side explanatory views of a room showing the actual usage state of the embodiment of the present invention, FIG. 3 is a plan view showing the external appearance of the embodiment, and FIG. Turn on the LED,
5 is a circuit diagram showing an example of an LED lighting circuit, FIG. 6 is a timing chart showing switching control voltages Ea to Ed, and FIGS. 7 and 8 are a conventional optical transmission system. FIG. 11... Light transmitting device, 13a-13d... Infrared light LE
D, 22a to 22d...switches, 26...timing clock generation section, 27... switching control voltage generation section. Applicant's agent Mr. Sato Figure 5 Figure 6 Inquiry

Claims (1)

[Claims] Light in which a current whose value changes depending on the data to be transmitted is passed through multiple light emitters, and each light emitter emits light whose intensity changes depending on the data in different directions. What is claimed is: 1. A light transmitting device for optical wireless paging, characterized in that the light transmitting device for optical wireless paging comprises time-sharing means for time-divisionally flowing a current whose value changes according to the data to each of the plurality of light emitters.