WO2005093974A1 - 受光器および赤外線通信装置 - Google Patents
受光器および赤外線通信装置 Download PDFInfo
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- WO2005093974A1 WO2005093974A1 PCT/JP2005/005496 JP2005005496W WO2005093974A1 WO 2005093974 A1 WO2005093974 A1 WO 2005093974A1 JP 2005005496 W JP2005005496 W JP 2005005496W WO 2005093974 A1 WO2005093974 A1 WO 2005093974A1
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- Prior art keywords
- light
- signal
- infrared
- circuit
- receiving
- Prior art date
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Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L12/00—Data switching networks
- H04L12/66—Arrangements for connecting between networks having differing types of switching systems, e.g. gateways
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
- H04B10/11—Arrangements specific to free-space transmission, i.e. transmission through air or vacuum
- H04B10/114—Indoor or close-range type systems
- H04B10/1149—Arrangements for indoor wireless networking of information
Definitions
- the present invention relates to a light receiver that receives light such as infrared light and generates an electric signal corresponding to the received light, and an infrared communication device that performs communication using infrared light as a medium.
- a photodiode or a phototransistor is often used as a light receiving element.
- a photodiode has a structure in which a semiconductor portion serving as a light receiving surface is exposed and has a high impedance, so that it has a considerable sensitivity to electromagnetic waves other than light alone. For this reason, electromagnetic shielding of photodiodes has been performed.
- a component for electromagnetically shielding a photodiode is disclosed in Patent Document 1, for example.
- Patent Document 1 a pedestal that forms a predetermined angle with respect to the substrate is provided on the substrate. Then, a plurality of photodiodes are mounted on the pedestal so that they can receive light from the respective directions in which light is to be received. In addition, one electromagnetic shield case is attached to the board to cover all these photodiodes.
- Non-Patent Document 1 As an infrared communication device as described above, there is a conventional infrared conference system (model: ATCS-50) disclosed in Non-Patent Document 1, for example.
- a so-called multi-channel light receiving / emitting unit 101 (model: ATCS-A50) as a relay device is attached to, for example, a ceiling of a conference room.
- the multi-channel light receiving / emitting unit 101 is connected via two coaxial cables 103 and 105 to, for example, a master control unit (model; ATCS- It is connected to C50 07.
- a plurality of terminal devices for example, a conference microphone unit (model; ATCS-M50) 109, 109,.
- conference microphone unit 109 when a speech is made using a certain conference microphone unit 109, an uplink FM (Frequency Modulation) signal according to the voice is generated.
- Conference microphone The unit 109 has an infrared light emitting diode (not shown) that emits light when the upstream FM signal is supplied. The infrared light emitted from the infrared light emitting diode enters the multi-channel light receiving / emitting unit 101.
- the multi-channel light receiving / emitting unit 101 has a light receiving circuit (not shown) for receiving the incident infrared light, and the infrared light received by the light receiving circuit is converted into an electric signal. As a result, the upstream FM signal is reproduced. Then, the reproduced uplink FM signal is transmitted to the master control unit 107 via the coaxial cable 103 dedicated for uplink.
- master control unit 107 demodulation processing is performed on an uplink FM signal received via uplink-only coaxial cable 103.
- the signal after the demodulation processing is input to a speaker (not shown) connected to the master control unit 107, whereby the voice (contents of the statement) of the speech source is reproduced.
- a downlink FM signal having a frequency band different from that of the uplink FM signal is generated. Then, the downlink FM signal is transmitted to the multi-channel light receiving / emitting unit 101 via the downlink dedicated coaxial cable 105.
- the multi-channel light emitting / receiving unit 101 has an infrared light emitting diode (not shown), and the infrared light emitting diode emits light by supplying a downlink FM signal received via a coaxial cable 105 dedicated for downlink.
- the infrared light emitted from the infrared light emitting diode is incident on each conference microphone unit 109, 109,.
- Each conference microphone unit 109 has a light receiving circuit (not shown) for receiving the incident infrared light, and the infrared light received by the light receiving circuit is converted into an electric signal. Then the down FM signal is reproduced. Then, the reproduced downlink FM signal is subjected to demodulation processing, and the demodulated signal is input to a monitor speaker (not shown) built in the conference microphone unit 109. As a result, the voice of the utterance source is also reproduced on each conference microphone unit 109 side.
- Non-Patent Document 1 In the prior art disclosed in Non-Patent Document 1, it is possible to simultaneously speak using up to four conference microphone units 109, 109, .... In other words, master control is performed from each conference microphone unit 109, 109,. Four channels are provided as so-called upstream audio channels leading to the unit 107. On the other hand, two channels are prepared as so-called downstream audio channels from the master control unit 107 to the conference microphone units 109, 109,... One of these is a channel for the main voice, which is used, for example, to transmit the voice of the utterer (downstream FM signal) as described above.
- the other one is a sub-audio channel, which is used, for example, to transmit a so-called simultaneous interpretation sound, which is a simultaneous interpretation of the speech (speech content) of the utterance source.
- a so-called simultaneous interpretation sound which is a simultaneous interpretation of the speech (speech content) of the utterance source.
- Each of the conference microphones 109, 109,... Is provided with a channel selection switch (not shown) for arbitrarily selecting one of the main audio channel and the sub audio channel. Only the sound of the channel selected by the switch (speaker's sound or simultaneous interpretation sound) is played from the monitor speaker. In addition to these audio channels, one control channel is also provided.
- Patent Document 1 JP-A-2002-190617
- Non-patent Document 1 Audiotech-Riki IR Conference System "ATCS-5"
- Patent Document 1 it is necessary to form an electromagnetic shield case so as to cover all the photodiodes. As a result, the equipment on which these photodiodes and electromagnetic shield cases are mounted becomes large.
- Non-Patent Document 1 the multi-channel light emitting / receiving unit 101 and the master control unit 107 are connected by two coaxial cables 103 and 105, in other words, only for the uplink. Since the coaxial cable 103 and the coaxial cable 105 dedicated for downlink are separately provided, there is a problem that the entire system is complicated and the cost is increased accordingly. This problem becomes more pronounced as the coaxial cables 103 and 105 become longer.
- a plurality (two) of downlink audio channels are prepared.
- the sensitivity of the multi-channel light receiving / emitting unit 101 to infrared light from each conference microphone unit 109, 109,... is there. That is, the infrared light emitting diode included in the multi-channel light receiving / emitting unit 101 is a so-called non-linear element whose emission output value is not proportional to the value of the forward voltage supplied thereto.
- the multi-channel light receiving / emitting unit 101 also has a function of receiving relatively weak infrared rays sent from the conference microphone units 109, 109,.
- the intermodulation product becomes noise, and as a result, the sensitivity of the multi-channel light receiving / emitting unit 101 to the infrared light reception Decreases. This problem becomes more remarkable as the distance between the infrared light emitting diode and the light receiving circuit for receiving the weak infrared light becomes shorter.
- Non-Patent Document 1 normal infrared communication may not be performed due to, for example, the influence of sunlight. Specifically, when sunlight enters any one of, for example, the conference microphone unit 109 near the window or the multi-channel light receiving / emitting unit 101, the infrared energy contained in the sunlight becomes a large noise, and It interferes with infrared communication between the conference microphone unit 109 and the multi-channel light emitting / receiving unit 1011. In order to avoid inconvenience, for example, each of the conference microphone units 109, 109,... It is good to block it, but it is very troublesome to take such measures.
- a plasma display device may be installed in a conference room or the like for presentations.
- the screen power of the plasma display device is also radiated by infrared rays which are noise for infrared communication according to the related art. It is known that Therefore, even in an environment where a powerful plasma display device is installed, the conference microphone units 109, 109,... It is necessary to take measures such as placing the multi-channel light receiving / emitting unit 101 or attaching an infrared shielding film (sheet) to the screen of the plasma display device, which is very troublesome.
- a discharge-type lighting device such as a xenon discharge tube is also a noise source that adversely affects the related art. Therefore, even in an environment where the discharge type lighting device is used, the above-mentioned plasma display device is installed even in an environment where the discharge type lighting device is used. It is necessary to take troublesome measures.
- the present invention is to provide a photodetector capable of reducing the size of the device when mounted on the device, as compared with the conventional technology disclosed in Patent Document 1, The purpose of this.
- the present invention provides an infrared communication device that simplifies the configuration of the entire system and lowers the cost as compared with the conventional technology disclosed in Non-Patent Document 1, and has higher light-receiving sensitivity. Is the second purpose.
- the present invention provides an infrared communication device capable of avoiding the influence of a noise source much more easily and effectively than the conventional technology disclosed in Non-Patent Document 1. Aim.
- a light receiver has a light receiving element that generates an electric signal in accordance with light reception to a light receiving unit.
- the light receiving element for example, a photodiode or a phototransistor can be used.
- the light-transmitting electromagnetic shield cover is provided on the light-receiving portion side of the light-receiving element.
- the electromagnetic shield cover is attached to each of the light receivers. Therefore, unlike the prior art disclosed in Patent Document 1, there is no need to use an electromagnetic shield cover that covers the entirety of a plurality of light receivers, so the device on which the light receiver is mounted, especially the plurality of light receivers, is mounted. It is possible to reduce the size of the device to be used.
- the electromagnetic shield cover can be formed integrally with the light receiving element.
- the light receiving element is provided with a light transmitting member, for example, An optical lens may be provided.
- an electromagnetic shield cover can be integrally formed inside the light transmitting member.
- the electromagnetic shield cover can be formed separately from the light receiving element.
- the electromagnetic shield cover provided on the light receiving section side of the light receiving element is attached to a substrate, particularly, for example, a substrate on which a circuit electrically connected to the light receiving element is formed.
- a light receiving element can be attached to the electromagnetic shield cover.
- the electromagnetic shield cover has a substrate fixing portion. It is desirable that the substrate fixing portion and the electromagnetic shield cover are formed integrally. Further, it is desirable that the substrate fixing portion and the electromagnetic shield cover form a predetermined angle. Further, the substrate fixing section is engageable with a fixing section provided on the substrate. Then, in this engaged state, the light receiving element forms a predetermined angle. With this configuration, the light receiving element forms a predetermined angle by engaging the substrate fixing portion with the fixing portion.
- the angle adjustment of the light receiving element can be performed at the same time by the work of mounting the shield case and the light receiving element in which the substrate fixing part is engaged with the fixing part, and the angle adjustment of the light receiving element becomes unnecessary.
- the light receiving element can have a predetermined angle without making any changes to the substrate or the like.
- the angle accuracy of the light receiving element is determined by the accuracy of the electromagnetic shield cover, the angle accuracy of the light receiving element is much higher than that of the conventional one.
- the light receiving element can be mounted on a mounting plate.
- This mounting plate is mounted on the electromagnetic shield cover. Since the light receiving element is mounted on the mounting plate, the light receiving element can be connected to the electric circuit on the substrate via the mounting plate.
- the light emitting element can be mounted on the mounting plate. In this case, it is possible to arrange the light emitting element so as to form a predetermined angle with respect to the substrate without any adjustment.
- a plurality of light receiving elements can be provided.
- the mounting plate and the seal As many light covers as the light receiving elements are provided.
- the corresponding light receiving elements are configured to form the same angle. With this configuration, all the light receiving elements can be easily attached so as to form a predetermined angle with respect to the substrate.
- the electromagnetic shield cover can be formed in a planar shape.
- the light receiver itself can be downsized, and the device in which the light receiver is mounted can be further downsized.
- the electromagnetic shield cover is flat, it is possible to easily block the reception of the interference light by a simple operation of attaching a light shield such as a light shield to the flat part.
- the infrared communication device is transmitted via one transmission line in a mixed state.
- the infrared light emitting diode has a characteristic that the light emission output value is substantially proportional to the forward current value.
- the light emitting means causes the infrared light emitting diode to emit light by flowing a current having a value corresponding to the magnitude of the plurality of first signals into the infrared light emitting diode in a forward direction.
- a plurality of first signals having different frequency bands are transmitted through one transmission line in a state where they are mixed with each other.
- the plurality of first signals are received by the receiving means, and the plurality of first signals received by the receiving means are provided to the light emitting means.
- the light emitting means includes an infrared light emitting diode, and causes the infrared light emitting diode to emit light based on the plurality of first signals provided from the receiving means. Thereby, infrared rays based on the plurality of first signals are emitted from the infrared light emitting diode.
- infrared light generated based on the second signal in a specific frequency band different from the frequency band of these first signals is received by the light receiving means.
- the light receiving means The second signal is reproduced from the infrared light thus obtained, and the reproduced second signal is sent to the above-mentioned transmission line by the transmission means.
- the plurality of first signals for emitting infrared light and the second signal reproduced from the received infrared light are transmitted through one common transmission line.
- the infrared light emitting diode has a characteristic that the light emission output value is substantially proportional to the value of the current flowing in the forward direction, that is, has a linear characteristic. Then, the light emitting means causes the current having a value corresponding to the magnitude of the plurality of first signals to flow in the forward direction to the infrared light emitting diode, thereby causing the infrared light emitting diode to emit light. By doing so, the infrared light emitting diode can be operated as a linear element, and the above-described mutual modulation product can be prevented from occurring. Therefore, the light receiving sensitivity does not decrease due to the intermodulation product.
- each of the plurality of first signals is desirably a frequency-modulated so-called FM signal 1S.
- the second signal is also an FM signal.
- the light emitting means may include a converting means for converting the plurality of first signals into a current, and a current supplying means for flowing the current converted by the converting means into the infrared light emitting diode. Good.
- the light receiving means may be provided near the infrared light emitting diode. That is, according to the second aspect, as described above, the intermodulation product does not occur due to the infrared rays emitted from the infrared light emitting diode. Therefore, even if the light receiving means is provided near the infrared light emitting diode, The light receiving sensitivity by the means does not decrease. Providing the light receiving means in the vicinity of the infrared light emitting diode in this way is advantageous in reducing the size of the entire device.
- detecting means for detecting the magnitude of the plurality of first signals received by the receiving means, for example, the signal level, and transmitting the plurality of first signals to a predetermined signal based on the detection result by the detecting means.
- the following inconvenience may be eliminated by providing the first adjusting means for adjusting the level to the level.
- the signal levels of the plurality of first signals transmitted through the transmission line are greatly attenuated.
- the signal levels of the plurality of first signals are attenuated.
- the signal levels of the plurality of first signals received by the receiving unit differ depending on the length of the transmission line and whether or not there is any signal attenuation means in the transmission line. Therefore, for example, if the infrared light emitting diode emits light simply based on the plurality of first signals received by the receiving means, the light emission output value
- the infrared light emitting diode may not be able to emit light with high efficiency. Therefore, the signal levels of the plurality of first signals received by the receiving means for solving such inconvenience are detected by the detecting means. Then, based on the detection result by the detecting means, the first signal is set so that the signal levels of the plurality of first signals become a predetermined level, for example, an appropriate level for causing the infrared light emitting diode to emit light with high efficiency.
- the adjusting means adjusts the signal levels of the plurality of first signals. In this way, the infrared light emitting diode can always emit light with high efficiency regardless of the length of the transmission line and the presence or absence of the signal attenuating means.
- a second adjusting means for adjusting the magnitude of the second signal based on the detection result by the detecting means may be provided.
- the signal level of the second signal sent to the transmission line changes according to the length of the transmission line and the presence or absence of the signal attenuating means, similarly to the first signal. That is, the receiving level of the second signal changes on the receiving side of the second signal. Therefore, it is desirable to provide a second adjusting means for keeping the reception level on the receiving side constant. That is, the second adjusting unit adjusts the signal level of the second signal based on the detection result by the detecting unit. Thereby, the reception level of the second signal on the receiving side of the second signal becomes constant regardless of the length of the transmission line and the presence or absence of the signal attenuating means.
- the infrared communication apparatus forms first communication areas different from each other and transmits the first communication areas.
- a plurality of light receiving means for receiving incoming infrared rays and converting them into a first signal, and a first invalidating means for manually electrically invalidating each of the plurality of light receiving means.
- a plurality of light receiving means are provided, and a plurality of first communication areas different from each other are formed by the plurality of light receiving means. Then, each of the light receiving means receives the infrared light transmitted from the first communication area formed by itself and converts it into a first signal.
- the individual light receiving means can be electrically invalidated by manual operation by the first invalidating means. Therefore, for example, even if a noise source exists in the first communication area of a certain light receiving means, if the light receiving means is electrically invalidated by a manual operation by the first invalidating means, the influence of the noise source can be reduced. Can be avoided.
- the first invalidating means invalidates the light receiving means by stopping supply of power to the light receiving means to be invalidated. In this way, power consumption of the disabled light receiving means can be suppressed, and the power consumption of the entire infrared communication device can be reduced.
- a plurality of second communication areas including an area common to each of the first communication areas are formed, and infrared rays according to the second signal for transmission are transmitted to the plurality of second communication areas. May be provided.
- a second invalidating means for manually invalidating each of the light transmitting means manually that is, when a certain light receiving means is invalidated, the first communication area by the invalidated light receiving means is outside the communication target area. Therefore, when the infrared communication device of the present invention includes not only a plurality of light receiving means but also a plurality of light transmitting means for transmitting infrared light, the area outside the strong communication target area is: It is not necessary to transmit the infrared rays. Therefore, it is desirable to provide second invalidating means for individually invalidating each light transmitting means in order to suppress transmission of useless infrared rays in such an area.
- the second invalidating means may be interlocked with the first invalidating means.
- the light transmitting means for forming a second communication area including an area common to the first communication area by the invalidated light receiving means. You may make it invalidate by invalidation means.
- the second invalidating unit also invalidates the light transmitting unit by stopping supply of power from the light transmitting unit to be invalidated.
- FIG. 1 is a perspective view of an infrared light emitting and receiving device using a light receiver according to a first embodiment of the present invention.
- FIG. 2 is a side view of the infrared emitting / receiving device of FIG. 1.
- FIG. 3 is an assembly view of the light receiver in FIG. 1.
- FIG. 4 is a side view of the light receiver in FIG. 1.
- FIG. 5 is a perspective view of a light receiver in FIG. 1.
- FIG. 6 is a side view showing a state where the light receiver in FIG. 1 is attached to a substrate.
- FIG. 7 is a front view, a side view, and an equivalent circuit diagram of a light receiver according to a second embodiment of the present invention.
- FIG. 8 is an equivalent circuit diagram showing a modified example of the light receiver of FIG. 7.
- FIG. 9 is a block diagram showing a schematic configuration of an infrared conference system according to a third embodiment of the present invention.
- FIG. 10 is an illustrative view showing a list of channels used in the infrared conference system in FIG. 9;
- FIG. 11 is a block diagram showing the internal configuration of the center device in FIG. 9.
- FIG. 12 is a block diagram showing an internal configuration of the mixing / distributing device in FIG. 9.
- FIG. 13 is a block diagram showing an internal configuration of the light transmitting and receiving device in FIG. 9.
- FIG. 14 is an electric circuit diagram showing details of a light transmitting circuit in FIG. 13.
- FIG. 15 is a graph showing forward current vs. relative light emission output characteristics of the infrared light emitting diode in FIG.
- FIG. 16 is a graph showing forward current versus series resistance characteristics of the PIN diode in FIG.
- FIG. 17 is an electric circuit diagram showing details of a current control circuit in FIG. 13.
- FIG. 18 is an illustrative view showing a voltage waveform at a point Pd in FIG. 14;
- FIG. 19 is a block diagram showing a schematic configuration of an infrared conference system according to a fourth embodiment of the present invention.
- FIG. 20 is an illustrative view showing a list of channels used in the infrared conference system in FIG. 19;
- FIG. 20 is an illustrative view showing a state in which the communication area of the light transmitting / receiving device in FIG. 19 is also viewed with a lateral force.
- FIG. 20 is an illustrative view showing a state in which the communication area of the light transmitting / receiving device in FIG. 19 is also viewed from above.
- FIG. 23 is a drawing schematically showing an internal structure of the light transmitting / receiving device in FIG. 19.
- FIG. 19 is an illustrative view showing a state in which the communication area of the terminal device in FIG. 19 is also viewed from the side, and [25] FIG.
- FIG. 26 is a block diagram showing an electrical configuration of the light transmitting and receiving device in FIG. 19.
- FIG. 27 is a block diagram showing details of a light receiving circuit in FIG. 26.
- FIG. 28 is an electric circuit diagram showing further details of the photoelectric conversion circuit in FIG. 27.
- FIG. 29 is a block diagram showing details of a light transmitting circuit in FIG. 26.
- FIG. 30 is an electric circuit diagram showing further details of the luminance modulation circuit in FIG. 29.
- FIG. 31 is a block diagram showing an electrical configuration of the terminal device in FIG. 19.
- FIG. 32 is an electric circuit diagram showing details of a light receiving circuit in FIG. 31.
- FIG. 33 is an electric circuit diagram showing details of a light transmitting circuit in FIG. 31.
- FIG. 34 is an illustrative view showing a state where an external noise source is present in a communication area of a certain light transmitting / receiving device in the infrared conference system of FIG. 19;
- FIG. 35 is an illustrative view showing a state in which an influence of an external noise source in FIG. 34 is eliminated.
- FIG. 36 is an illustrative view showing a state where an external noise source exists in a communication area of a certain terminal device in the infrared conference system of FIG. 19;
- FIG. 37 is an illustrative view showing a state where an influence of an external noise source in FIG. 36 is eliminated.
- FIG. 38 is a block diagram showing a schematic configuration of a conventional infrared conference system. BEST MODE FOR CARRYING OUT THE INVENTION
- the light receiver according to the first embodiment is used, for example, in an infrared transmitter / receiver similar to that in an infrared conference system 1010 according to a third embodiment (or an infrared conference system 2010 according to the fourth embodiment) described later. Is done. That is, in an infrared conference system, for example, a bidirectional optical communication (infrared ray) using an infrared medium between a terminal device installed on a desk in a conference room and an infrared transmitting / receiving device installed on a ceiling, for example. Communication).
- a plurality of light receivers 4 are annularly arranged on a substrate 2.
- the substrate 2 is, for example, a printed substrate formed in a disk shape and having a predetermined circuit pattern formed on a surface opposite to a surface on which the light receiver 4 is installed.
- Each light receiver 4 receives the infrared light transmitted from the terminal device described above and generates an electric signal.
- each of the light receivers 4 has a light receiving element, for example, a photodiode 6.
- the photodiode 6 is of a planar type, and an infrared ray is incident on a light receiving surface 6a which is a front surface thereof.
- a plurality of leads 8 protrude.
- the photodiode 6 is arranged such that the back side thereof is in contact with a mounting plate, for example, a mounting surface of a small printed circuit board 10, and each lead 8 is connected to a predetermined position of a pattern formed on the small printed circuit board 10. I have. Therefore, the light receiving surface 6a of the photodiode 6 and the mounting surface of the small printed circuit board 10 are parallel.
- connection terminal 12 for connection to the board 2 is arranged below the photodiode 6 on the small printed circuit board 10.
- One end of each pin 12 a of the connection terminal 12 is inserted into a predetermined position on the small printed circuit board 10 and connected to a pattern formed on the small printed circuit board 10.
- the other end of each of the pins 12a is inserted into a predetermined position on the substrate 2, and the photodiode 6 is connected to a predetermined pattern on the substrate 2.
- An electromagnetic shield cover 14 is arranged on the light receiving surface 6a side of the photodiode 6.
- the shield cover 14 is made of a conductive material, for example, iron or aluminum, and can cover both sides and the upper part of the photodiode 6 and the connection terminal 12, and is slightly smaller and smaller than the small printed circuit board 10. It has a frame-shaped body 14a.
- a window 14b having a size corresponding to the light receiving surface 6a of the photodiode 6 is formed on the front side of the frame 14a in parallel with the light receiving surface 6a.
- This window 14b has a cross-shaped grid 14c is formed.
- linear substrate fixing parts 14d are formed integrally therewith and extend rearward. As shown in FIG. 4, the substrate fixing portion 14d and the frame 14a are arranged so as to form a predetermined angle, for example, an acute angle.
- a tongue piece 14e extending linearly rearward is formed on the body. These tongue pieces 14e are inserted into through holes 10a formed in the small printed circuit board 10 correspondingly, and are fixed to the small printed circuit board 10 side by soldering or the like.
- the electromagnetic shield cover 14 is attached to the small printed circuit board 10 with the window 14b of the electromagnetic shield cover 14 being parallel to the light receiving surface 6a of the photodiode 6, as shown in FIG.
- the light receiving surface 6a is covered with the electromagnetic shield cover 14. That is, the electromagnetic shield cover 14 is attached to each photodiode. Also, since the photodiode 6 is a flat type and the light receiving surface 6a side of the photodiode 6 is covered with the electromagnetic shield cover 14 close to the photodiode 6, the thickness of the light receiver 4 can be reduced. .
- an engaging portion for example, a tongue piece 14f is formed integrally with the substrate fixing portion 14d at the center of both lower portions thereof and perpendicular to the substrate fixing portion 14d.
- the tongue piece 14f is engaged with a fixing portion formed on the board 2 corresponding to the tongue piece 14f, for example, a through hole (not shown).
- the tongue piece 14f is soldered to a reference potential pattern (not shown) formed on the substrate 2, for example.
- the lower portion of the fixing portion 14d is in contact with the substrate 2, and the electromagnetic shield cover 14 and the photodiode 6 are attached at a predetermined angle ⁇ ⁇ ⁇ ⁇ with respect to the substrate 2.
- the electromagnetic shield cover 14 is connected to the reference potential pattern, the electromagnetic shield is applied to the photodiode 6 by the electromagnetic shield cover 14.
- the photodiode 6 automatically forms a predetermined light receiving angle. Therefore, it is not necessary to adjust the light receiving angle of the photodiode 6 after mounting.
- the light receiving angle does not change, and the light receiving angle is the same even when it is mounted on another substrate 2 having the same configuration, and the light receiving angle does not vary from one substrate 2 to another.
- the substrate 2 is mounted on the ceiling such that each light receiver 4 is located on the lower side. Therefore, from a terminal device such as a desk You can receive the transmitted infrared light.
- a plurality of light emitting elements for example, a plurality of LEDs 16 are formed inside each light receiver 4 in a ring shape and form a predetermined angle with respect to the substrate 2. Mounted. These LEDs 16 transmit infrared rays toward the terminal device on the desk in a state where the board 2 is mounted on the ceiling as described above.
- an infrared transmission type power bar is attached so as to cover each of the light receivers 4 and the LEDs 16 on the substrate 2.
- each light receiver 14 and each LED 16 are separately mounted on the substrate 2.
- the tip of the small printed circuit board 10 can be further extended, and the LED 16 can be attached to this extension.
- the receiver 4 and the LED 16 can be set at the same angle at the same time without adjusting the angle as much as the receiver 4 and the LED 16 can be mounted simultaneously. be able to.
- the light receiver 4 in the above-described first embodiment is provided with the electromagnetic shield cover 14 separately from the photodiode 6, but the light receiver 4a in the second embodiment is integrated with the photo diode 60.
- an electromagnetic shield cover 140 Provided with an electromagnetic shield cover 140. That is, as shown in FIGS. 7 (a) and 7 (b), the photodiode 60 is entirely housed in a housing 62 made of infrared transmitting resin.
- the electromagnetic shield cover 140 is disposed in the housing 62 so as to be located at a predetermined interval in front of the light receiving surface 60a of the photodiode 60.
- the electromagnetic shield cover 140 is formed in a lattice shape from a conductive material, and is arranged so as to cover the entire light receiving surface 60a of the photodiode 60.
- FIG. 7 (c) is an equivalent circuit diagram of the light receiver 4a.
- one photodiode 60 corresponds to one photodiode. Since the electromagnetic shield cover 140 is provided, the size of the light receiver 4a can be further reduced than that of the light receiver 4 of the first embodiment. Therefore, the infrared transmitting / receiving device, which is an example of a device equipped with the powerful photodetector 14a of the second embodiment, can be further miniaturized.
- a lead 142 is provided to connect the electromagnetic shield cover 140 to the reference potential.
- the photodiode 60 is normally used in a reverse-biased state, and its power source is AC-connected to a reference potential. Therefore, if the electromagnetic shield cover 140 is connected to the force sword in the housing 62 as shown in FIG. 8, the lead 142 does not need to be provided.
- a force using a photodiode as a light receiving element for example, a phototransistor, which is not limited to this, can also be used.
- the same technology as in the first and second embodiments may be applied to electronic devices other than the infrared light transmitting and receiving device, for example, devices that receive light other than infrared light.
- the infrared conference system 1010 includes one center device 1012 as a main device and a plurality of light transmitting and receiving devices 101 4 as an infrared communication device. , 1014,... And a plurality of terminal devices 1016, 1016,.
- the center device 1012 is installed, for example, in a corner of a conference room, and the light transmitting / receiving devices 1014, 1014,... Are mounted on the ceiling or the wall surface of the conference room.
- the terminal devices 1016, 1016,... Are arranged at appropriate positions in the conference room, for example, on a table.
- the center device 1012 has a plurality of, for example, four input / output terminals 1018, 1018,..., And the light transmitting / receiving device 1014 can be connected to each of the four input / output terminals 1018, 1018,. Have been. Specifically, as shown in the input / output terminal 1018 shown at the top of FIG. 9, one transmission / reception device 1014 is connected to the input / output terminal 1018 via one coaxial cable 1020 as a transmission line. Can be connected. In addition, as shown in the input / output terminal 1018 shown second from the top in FIG. A plurality of, for example, up to four light transmitting / receiving devices 1014, 1014,... Can be simultaneously connected to the input / output terminal 1018.
- the mixer / distributor 1022 includes one primary terminal 1024 and four secondary terminals 1026, 1026,
- the primary terminal 1024 is connected to the input / output terminal 1018 of the center device 1012 via the coaxial cable 1020 or to the secondary terminal 1026 of another mixing / distributing device 1022.
- Each of the secondary terminals 1026 is connected to a light transmitting / receiving device 1014 via a coaxial cable 1020 or to a primary terminal 1024 of another mixer / distributor 1022. Note that there may be a secondary terminal 1026 to which no connection is made.
- the powerful mixing / distributing device 1022 is installed, for example, behind a ceiling or a wall.
- the overall operation of the infrared conference system 1010 will be briefly described. For example, it is assumed that a speech request has been made by a certain terminal device 1016. This comment request is made by operating a comment request switch (not shown) provided in the terminal device 1016. Then, in the terminal device 16, uplink control data indicating that the utterance request has been made and the request source (identification number) of the utterance request is generated, and furthermore, control of a predetermined frequency band is performed based on the uplink control data. Uplink FM signal is generated. The terminal device 1016 has an infrared light emitting diode (not shown), and causes the infrared light emitting diode to emit light based on the control uplink FM signal. As a result, infrared light having a wavelength of, for example, 870 [nm] is emitted from the infrared light emitting diode (terminal device 1016).
- the infrared light emitted from the terminal device 1016 is incident on the light transmitting / receiving device 1014 near the terminal device 1016.
- the light transmitting / receiving device 1014 has a light receiving circuit 1140 described later as a light receiving means for receiving the incident infrared light.
- the infrared light received by 140 is converted into an electric signal.
- the above-mentioned control uplink FM signal is reproduced.
- the reproduced uplink FM signal for control is transmitted to the center device 1012 via the coaxial cable 1020 or, in addition, via one or more mixer / distributors 1022.
- the center device 1012 receives the control uplink FM signal transmitted from the light transmitting / receiving device 1014, performs demodulation processing on the received control uplink FM signal, and extracts uplink control data. . Then, the content of the extracted uplink control data is analyzed, and the fact that the utterance request has been made and the terminal device 1016 that is the request source of the utterance request are recognized. Then, it generates downlink control data for allowing the terminal device 1016 that is the request source to speak, and further, based on the downlink control data, a frequency band different from the above-mentioned control uplink FM signal. Generate downlink FM signal for control of This downlink FM signal for control is transmitted to all the light transmitting / receiving devices 1014, 1014,... Via the coaxial cable 1020 or also via one or more mixing / distributing devices 1022.
- Each of the light transmitting and receiving devices 1014, 1014,... Has an infrared light emitting diode 1142, 1142,... Described later, and these light emitting diodes 1142, 1142,. It emits light based on the downlink FM signal for control sent from 1012.
- all the light transmitting / receiving devices 1014, 1014,... (Infrared light emitting diodes 1142, 1142, ") emit infrared light having a wavelength of, for example, 870 [nm]. It is shot at 1016, 1016,....
- Each of the terminal devices 1016, 1016,... Has a light receiving circuit (not shown) for receiving the incident infrared light, and the infrared light received by the light receiving circuit is converted into an electric signal. .
- the downlink FM signal for control is reproduced.
- the reproduced downlink FM signal for control is subjected to demodulation processing, whereby downlink control data is extracted.
- only the terminal device 1016 that has received the downlink control data sent to itself is allowed to speak, so that it is activated.
- an uplink FM signal is generated.
- This uplink FM signal is a signal in a frequency band different from the above-mentioned control uplink FM signal, and the frequency band is specified by the above-mentioned downlink control data.
- the above-mentioned infrared light emitting diode emits light based on this uplink FM signal, whereby infrared light is emitted from the infrared light emitting diode.
- the infrared light is incident on the light transmitting / receiving device 1014 near the terminal device 1016 that is the utterance source. Then, the incident infrared light is received by the above-described light receiving circuit 1140, and is converted into an upstream FM signal. Then, the converted uplink FM signal is transmitted to center apparatus 1012 via the same transmission path as the above-mentioned control uplink FM signal.
- the center device 1012 receives the uplink FM signal transmitted from the light transmitting / receiving device 1014, and performs demodulation processing on the received uplink FM signal. Then, the signal (voice signal) after the demodulation processing is input to a speaker (not shown) connected to the center device 1012, thereby reproducing the voice (the content of the voice) of the speech source. Further, center apparatus 1012 generates a downlink FM signal based on the demodulated signal. This downlink FM signal is transmitted to all of the light transmitting and receiving devices 1014, 1014,..., Similarly to the above-described control downlink FM signal.
- each of the light transmitting and receiving devices 1014, 1014,... The above-described light emitting diodes 1142, 1142,... Emit light based on the downlink FM signal transmitted from the center device 1012. As a result, all the light transmitting / receiving devices 1014, 1014,... (Infrared light emitting diodes 1142, 1142,. Then, this infrared ray is incident on each terminal device 1016, 1016,...
- each of the terminal devices 1016, 1016,... The incident infrared light is received by the above-described light receiving circuit, and is converted into a downlink FM signal. Then, demodulation processing is performed on the downlink FM signal, and the demodulated signal (audio signal) is input to a monitor speaker (not shown) built in the terminal device 1016. As a result, in all the terminal devices 1016, 1016,.
- speech can be simultaneously made by a maximum of four terminal devices 1016, 1016,...
- the upstream voice channel from each of the terminal devices 1016, 1016,... To the center device 1012 via the light transmitting and receiving devices 1014, 1014,.
- a control channel CHO with a center frequency of 6.45 [MHz] is also provided. This control channel is used to transmit the above-mentioned uplink control data.
- two channels are prepared as so-called downlink audio channels from the center device 1012 to the terminal devices 1016, 1016,... Via the light transmitting / receiving devices 1014, 1014,.
- a channel CH1 with a center frequency of 1.95 [MHz] and a channel CH2 with a center frequency of 2.25 [MHz] are prepared.
- channel CH1 is a channel for the main voice, and is used for transmitting, for example, the voice of the originator (downward FM signal) as described above.
- the channel CH2 is a channel for sub-speech, and is used, for example, to transmit a so-called simultaneous interpretation sound, which is a simultaneous interpretation of the speech (speech content) of the utterance source.
- the simultaneous interpretation sound is input, for example, through a microphone (not shown) connected to the center device 1012.
- a downlink FM signal of the sub audio channel CH2 is generated based on the simultaneous interpretation sound (audio signal), and the downlink FM signal is mixed with the downlink FM signal of the main audio channel CH1 (voice source voice).
- the simultaneous interpretation sound is input, for example, through a microphone (not shown) connected to the center device 1012.
- a downlink FM signal of the sub audio channel CH2 is generated based on the simultaneous interpretation sound (audio signal), and the downlink FM signal is mixed with the downlink FM signal of the main audio channel CH1 (voice source voice).
- the simultaneous interpretation sound is input, for example, through a microphone (not shown) connected to the center device 1012.
- a downlink FM signal of the sub audio channel CH2 is generated based on the simultaneous interpretation sound (audio signal)
- the downlink FM signal is mixed with the downlink FM signal of the main audio channel CH1 (voice source voice).
- it is transmitted to each of the light transmitting
- Each of the terminal devices 1016, 1016,... Is provided with a channel selection switch (not shown) for arbitrarily selecting one of the main audio channel CH1 and the sub audio channel CH2. Only the sound of channel CH1 or CH2 selected (original sound or simultaneous interpretation sound) is played from the monitor speaker.
- any control data can be superimposed as a sub-carrier.
- the center device 1012 and each of the light transmitting / receiving devices 1014 are mutually connected via one coaxial cable 1020 (or also via the mixing / distributing device 1022). ⁇ ⁇ , and the upstream FM signals of the multiple channels CH0-CH5 and the downstream FM signals of the multiple channels CH1 and CH2 are transmitted via this single coaxial cable 1020.
- DC power as a drive power supply for the light transmitting and receiving device 1014 is also supplied from the center device 1012 to each light transmitting and receiving device 1014 via the coaxial cable 1020.
- the center device 1012 is configured as follows.
- the center device 1012 has a mixing / distribution circuit 1120, and individual DC cuts are provided on the secondary side (right side in FIG. 11) of the mixing / distribution circuit 1120.
- a transmission circuit 1126 is connected to the primary side (left side in FIG. 11) of the mixing and distribution circuit 1120 via a low-pass filter (LPF) 1124.
- a receiving circuit 1128 is connected to the primary side via a high-pass filter (HPF) 1128.
- HPF high-pass filter
- the cutoff frequency of the low-pass filter 1124 is higher than the upper limit frequency of the downlink channels CH1 and CH2 (frequency obtained by adding a predetermined bandwidth to 2.25 [MHz]), and the lower limit of the uplink channels CH0 and CH4. It is set to a value lower than the frequency (frequency obtained by adding a predetermined bandwidth to 6.45 [MHz]), and for example, 2.39 [MHz].
- the cutoff frequency of the bypass filter 1128 is set to a value higher than the cutoff frequency of the lowpass filter 1124 and lower than the lower limit frequency of the upstream channels CH0 to CH4, for example, 6.63 [MHz]. ing.
- the center device 1012 has a power supply circuit 1132 for generating the above-described DC power as a drive power supply for each of the light transmitting / receiving devices 1014, 1014,. 24 [V] DC power is supplied to the input / output terminals 1018, 1018,... Via the individual low-nos filters 1134, 1134,. These low-pass filters 1134, 1134,... Are for AC cut, and the cutoff frequency is about several [Hz] to about ten and several [Hz]. According to the center device 1012 configured as described above, the upstream FM signals to which the power transmitting and receiving devices 1014, 1014,... Are also transmitted are transmitted via the respective input / output terminals 1018, 1018,. Input into device 1012.
- upstream FM signals are input to the secondary side of the mixing / distributing circuit 1120 via the individual DC cut capacitors 1122, 1122,... And mixed with each other in the mixing / distributing circuit 1120. Then, the mixed FM signal is output from the primary side of the mixing and distribution circuit 1120 and input to the receiving circuit 1130 via the high-pass filter 1128. Receiving circuit 1130 performs the above-described decoding process on the input mixed FM signal. Then, the signal after the decoding processing is sent to a subsequent circuit (not shown).
- the downlink FM signal is generated by the transmission circuit 1126. Then, this downstream FM signal is input to the primary side of the mixing and distribution circuit 1120 via the low-pass filter 1124, and is divided into four in the mixing and distribution circuit 1120.
- the distributed downstream FM signal is output from the secondary side of the mixing / distribution circuit 1120 and sent to the input / output terminals 1018, 1018,... Via the individual DC cut capacitors 1122, 1122,.
- the signal is transmitted from each input / output terminal 1018 to each of the light transmitting / receiving devices 1014, 1014,... Via coaxial cable 1020 or via one or more mixing / distributing devices 1022. Note that the above-described DC power supply is also sent to each of the light transmitting / receiving devices 101 4, 1014,.
- the mixing / distributing device 1022 has a mixing / distributing circuit 1220, and a DC cut capacitor 12 22 is provided on the primary side (left side in FIG. 12) of the mixing / distributing circuit 1220.
- Primary terminal 1024 is connected via.
- the secondary side (right side in FIG. 12) of the mixing / distributing circuit 1220 is connected to the respective secondary terminals 1026, 1026,... Via individual DC cut capacitors 1224, 1224,.
- the primary terminal 1024 is connected to each of the secondary terminals via an AC cut low-noise finolators 1226 and low-noise finolators 1228, 1228,... Provided corresponding to the secondary terminals 1026, 1026,. 1026, 10 26, ... [This is connected.
- the power-off frequency of each of the Rhonos finoletors 1226 and 1228 is on the order of several [Hz]-"h several [Hz].
- the lower signal input from the primary terminal 1024 The FM signal is input to the primary side of the mixing and distribution circuit 1220 via the DC cut capacitor 1222, and is divided into four in the mixing and distribution circuit 1220. Then, the distributed downstream FM signal is output from the secondary side of the mixing and distribution circuit 1220, and is output from the respective secondary terminals 1026, 1026,... Via individual DC cut capacitors 1224, 1224,. You. Further, the DC power input from the primary terminal 1024 in a state of being superimposed on the downstream FM signal is transmitted to the secondary terminals 1026, 1026, ... power is output.
- the upstream FM signals input from the respective secondary terminals 1026, 1026,... are input to the secondary side of the mixing and distribution circuit 1220 via the individual DC power capacitors 1224, 1224,. They are mixed together in a distribution circuit 1220. Then, the mixed FM signal is output from the primary side of the mixing and distribution circuit 1220, and is output from the primary terminal 1024 via the DC cut capacitor 1222.
- Each of the light transmitting and receiving devices 1014 is configured as follows. That is, as shown in FIG. 13, the light transmitting / receiving device 1014 is provided with a terminal 1144 to which a coaxial cable 1020 is connected, and through the terminal 1144, the above-described downlink FM signal and DC power are transmitted to the light transmitting / receiving device 1014. Is entered in Also, the uplink FM signal is output to the coaxial cable 1020 via the terminal 1144.
- the DC power input from the terminal 1144 is input to the power supply circuit 1146.
- the power supply circuit 1146 generates power supply voltages Vccl, Vcc2,..., which will be described later, for driving each circuit in the light transmitting and receiving device 1014 based on the input DC power.
- the downstream FM signal input from terminal 1144 is input via DC cut capacitor 1148 to low-pass filter 1150 as receiving means.
- the cut-off frequency of this low-pass filter 1150 is set to a value that is higher than the upper limit frequency of the downlink FM signal (downlink channels CH1 and CH2) and lower than the lower limit frequency of the uplink FM signal (uplink channels CH0–CH4). For example, it is 2.39 [MHz]. Therefore, the downstream FM signal input to the low-pass filter 1150 passes through the low-pass filter 1150, and further passes through the resistor 1152 and the two DC cut capacitors 1154 and 1156 to the amplification circuit 1158. Will be entered.
- the amplifier circuit 1158 increases the input downlink FM signal by a predetermined amount.
- the downstream FM signal amplified by the width factor and amplified is input to a light transmitting circuit 1160 as light emitting means.
- the light transmitting circuit 1160 has the above-mentioned infrared light emitting diodes 1142, 1142, ... connected in series. These infrared light emitting diodes 1142, 1142,... Are arranged in different directions to emit infrared light in various directions. By flowing a current Id having a magnitude corresponding to the signal level of the above down-FM signal to these infrared light emitting diodes 1142, 1142, ..., the respective infrared light emitting diodes 1142, 1142, ... emit light.
- a voltage / current conversion circuit 1162 is provided.
- the voltage-current conversion circuit 1162 includes an operational amplifier 1164, an N-channel FET (Field Effect Transistor) 1166, and a resistor 1168.
- the FM signal amplified by the amplifier circuit 1158 is input to the non-inverting input terminal of the operational amplifier 1164.
- the output terminal of the operational amplifier 1164 is connected to the gate terminal of the FET 1166, and the inverting input terminal of the operational amplifier 1164 is connected to the source terminal of the FET 1166. This source terminal is connected to the ground potential (GND) via a resistor 1168.
- the cathode side of the series circuit of the infrared light emitting diodes 1142, 1142,... Is connected to the drain terminal of the FET 1166. Are applied.
- a current Id according to the signal level of the FM signal input to the non-inverting input terminal of the operational amplifier 1164 flows through each infrared light emitting diode 1142, 1142,.
- each of the infrared light emitting diodes 1142, 1142,... Emits light, so that the luminance is modulated.
- infrared rays based on the downlink FM signal are emitted from each infrared light emitting diode 1142, 1142,.
- Each of the infrared light emitting diodes 1142, 1142,... Is a so-called non-linear element whose emission output is not proportional to the forward voltage. As shown in FIG. The emission output is proportional and has a so-called linear characteristic. Therefore, as shown in FIG. 14, the FM signal is converted into a current Id by the voltage-current conversion circuit 1162, and each infrared light emitting diode 1142, 1142,... Emits light by the converted current Id. This can prevent the above-described intermodulation products from occurring.
- the light transmitting / receiving device 1014 has the above-described light receiving circuit 1140 for receiving the infrared rays emitted from each (nearby) terminal device 1016, 1016,.
- the light receiving circuit 1140 has a plurality of phototransistors (not shown) for receiving the infrared rays, and these phototransistors should receive infrared rays to which various directional forces are also sent. Are arranged in different directions from each other.
- the phototransistor is provided relatively close to the infrared light emitting diodes 1142, 1142,....
- the infrared light received by the light receiving circuit 1140 is converted into an upstream FM signal, and the converted upstream FM signal is input to the amplifier circuit 1176 via the resistor 1170 and the two DC cut capacitors 1172 and 1174.
- the amplification circuit 1176 amplifies the input upstream FM signal at a predetermined amplification factor, and the amplified upstream FM signal is input to a high-pass filter 1178 as a transmission unit.
- the cut-off frequency of the high-pass filter 1178 is set to a value higher than the cut-off frequency of the above-described single-pass filter 1150 and lower than the lower limit frequency of the uplink FM signal (uplink channel CHO-CH4). For example, it is 6.63 [M Hz]. Therefore, the upstream FM signal input to the high-pass filter 1178 passes through the high-pass filter 1178 and is further sent to the terminal 1144 via the DC cut capacitor 1148.
- the mixer / distributor 1022 includes a mixer / distributor circuit 1220.
- the mixer / distributor circuit 1220 includes impedance components such as coils to realize signal mixing and distribution. I have.
- the impedance component such as the coil is a factor for attenuating the level of a signal to be mixed or distributed, that is, a signal attenuating means. Therefore, for example, each of the light transmitting / receiving devices 1014 and 101 depends on whether the mixing / distributing device 1022 is interposed and whether or not the number of the mixing / distributing device 1022 is interposed. There is a difference in the signal level (reception level) of the downstream FM signal input to 4, ... Similarly, on the center device 1012 side, a difference occurs in the signal level of the uplink FM signal sent from each of the light transmitting / receiving devices 1014, 1014,. Therefore, in the third embodiment, the following devices are devised for each transmitting / receiving device 1014 for eliminating such a difference in signal level.
- the power source terminal of the PIN diode 1184 is connected to the interconnection point of the two DC cut capacitors 1154 and 1156 on the downstream path, so to speak.
- the power source terminal of the PIN diode 1190 is connected to the interconnection point of the two DC cut capacitors 1172 and 1174 on the upstream path.
- a capacitor 1196 is connected between the connection point between the power supply line Vcc2 and the coil 1182 and the ground potential, and the capacitor 1196 and the coil 1182 reduce the power of the FM signal.
- An AC blocking circuit for blocking the flow into the line Vcc2 is formed.
- a capacitor 1198 is connected between a connection point between the coil 1182 and the anode terminal of the PIN diode 1184 and the ground potential. That is, the anode terminal of the PIN diode 1184 is AC-connected to the ground potential.
- the PIN diode 1184 has a resistance value that is substantially inversely proportional to the forward current Ic flowing through itself.
- the resistance value of the PIN diode 1184 becomes approximately 1.5 [kQ] -2.5 [ ⁇ ] It changes within the range. Therefore, the downstream FM signal output from the above-described low-pass filter 1150 is divided by the resistor 1152 and the PIN diode 1184, and the divided downstream FM signal is input to the amplifier circuit 1158. That is, the resistor 1152 and the PIN diode 1184 form an attenuator circuit having a variable attenuation factor.
- the resistance value of the resistor 1152 is, for example, 150 [ ⁇ ].
- a capacitor is provided between the connection point between coil 1186 and coil 1188 and the ground potential. 1200 capacitors are connected, and the capacitor 1200 and the two coils 1186 and 1188 form an AC blocking circuit for preventing the downstream FM signal and the upstream FM signal from mixing with each other. Further, a capacitor 1202 is connected between the connection point between the coil 1188 and the anode terminal of the PIN diode 1190 and the ground potential. That is, the anode terminal of the PIN diode 1190 is AC-connected to the ground potential.
- the PIN diode 1190 has the same standard as the PIN diode 1184 described above, that is, has a forward current-resistance characteristic shown in FIG.
- the upstream FM signal output from the light receiving circuit 1140 is divided by the resistor 1170 and the PIN diode 1190, and the divided upstream FM signal is input to the amplifier circuit 1176. That is, the resistor 1170 and the PIN diode 1190 form an attenuator circuit having a variable attenuation rate. Note that the resistor 1170 is also the same 150 [ ⁇ ] as the resistor 1152 described above.
- a capacitor 1204 is connected between the connection point between the coil 1192 and the current control circuit 1194 and the ground potential.
- the capacitor 1204 and the coil 1192 control the upstream F ⁇ ⁇ signal by current control.
- An AC blocking circuit is formed to block the flow into the circuit 1194.
- the current control circuit 1194 controls the current Ic according to the signal level (reception level) of the downstream FM signal. Specifically, the current control circuit 1194 follows the DC signal Va provided from the rectifier circuit 1206. Control.
- the rectifier circuit 1206 is input via a DC cut capacitor 1208 for the downstream FM signal amplified by the amplifier circuit 1158.
- the rectifier circuit 1206 rectifies the input downstream FM signal and converts it into the above-described DC signal Va having a voltage value according to the reception level of the downstream FM signal.
- current control circuit 1194 has two resistors 1210 and 1212 for dividing the above-described DC signal Va, and these resistors 1210 and 1212
- the input signal is input to the base terminal of an NPN transistor 1214.
- the above-described coil 1192 is connected to the collector terminal of the transistor 1214. Note that the emitter terminal of the transistor 1214 is connected to the ground potential.
- the current Ic increases as the reception level of the downlink FM signal increases.
- the resistance value of the PIN diode 1184 decreases.
- the down FM signal is greatly attenuated by the attenuator circuit including the PIN diode 1184 and the resistor 1152.
- the lower the reception level of the downstream FM signal the lower the current Ic.
- the resistance value of the PIN diode 1184 increases, and as a result, the attenuation rate of the downstream FM signal by the attenuator circuit decreases. That is, the attenuation rate of the attenuator circuit changes according to the reception level of the downlink FM signal.
- the signal level of the downlink FM signal is previously set to a higher level.
- the reception level of the downlink FM signal is higher than necessary. That is, according to the third embodiment, the signal level of the downlink FM signal set in advance is attenuated by the variable attenuator circuit of the PIN diode 1184 and the resistor 1152, as described above, so that the mixing distributor The infrared light emitting diodes 1142, 1142,...
- the infrared light emitting diodes 1142, 1142,... are automatically controlled to have a constant light emission output power.
- the peak “to” peak is determined with reference to +1 [V].
- the value is 2 [V]
- the infrared light emitting diodes 1142, 1142, ... emit light with the highest efficiency.
- the signal level of the downlink FM signal is set at the output stage from the center device 1012 so that this condition is satisfied, that is, each infrared light emitting diode 1142, 1142, ... always emits light with high efficiency. .
- the attenuation rate of the PIN diode 1190 and the resistor 1170 by the attenuator circuit is also lower than the attenuation rate of the downlink FM signal. Will change accordingly.
- the signal level of the upstream FM signal output from the light receiving circuit 1140 is set to be higher in advance. That is, the signal level of the upstream FM signal set in advance is set to the PIN diode 1190 and the resistor
- the signal level (transmission level) of the upstream FM signal is adjusted according to the reception level of the downstream FM signal by attenuating the variable attenuator circuit with the 1170. Therefore, regardless of whether the mixing / distributing device 1022 intervenes and the number of the mixing / distributing devices 1022, the center apparatus 1012 can always receive the uplink FM signal at a constant signal level. it can.
- the center device 1012 and each of the light transmitting / receiving devices 1014 are connected via one coaxial cable 1020. . Therefore, the configuration of the entire infrared conference system 1010 is smaller than that of the conventional technology disclosed in Non-Patent Document 1 in which the coaxial cable 103 dedicated for uplink and the coaxial cable 105 dedicated for downlink are separately provided. Simplification and low cost can be achieved.
- each infrared light emitting diode 1142, 1142, ... of the light transmitting and receiving device 1014 can be subjected to luminance modulation by a current Id having a magnitude corresponding to the signal level of the down FM signal, it is disclosed in Non-Patent Document 1.
- no intermodulation products are generated. That is, the light receiving sensitivity of the light transmitting and receiving device 1014 does not decrease due to the intermodulation product. Therefore, higher light-receiving sensitivity can be obtained than in the related art disclosed in Non-Patent Document 1.
- the light emission output of the infrared light emitting diodes 1142, 1142,... is automatically controlled to be constant.
- the reception level of the uplink FM signal on the side of the center device 1012 is also automatically controlled to be always constant. Therefore, stable infrared communication can always be performed.
- the present invention is not limited to this. That is, the same technology as in the third embodiment may be applied to an infrared communication device used for a purpose other than the infrared conference system 1010.
- the channel assignment shown in FIG. 10 is merely an example, and is not limited to this. It is not something to be done. That is, the number of channels, frequency, and modulation method may be different from those shown in FIG.
- FIGS. 11, 12, 13, 14, and 17 show the respective circuit configurations. This is also an example to the extent that it is tired, and is not limited thereto.
- the infrared conference system 2010 also has one center device 2012 as a main device and a plurality of relay devices as relay devices. , And a plurality of terminal devices 2018, 2018,... Each having a microphone 2016.
- the center device 2012 is installed, for example, in the corner of the conference room, and the light transmitting and receiving devices 2014, 2014,... Are mounted on the ceiling or the wall surface of the conference room.
- Each terminal device 2018, 2018,... Is arranged at an appropriate place in the conference room, for example, on a table for each speaker.
- Each terminal device 2018, 2201,... Is assigned an individual identification number.
- the center device 2012 has a plurality of, for example, four input / output terminals 2020, 2020,..., And each of the four input / output terminals 2020, 2020,. 014 can be connected.
- one transmission / reception device 2014 can be connected via one coaxial cable 2022 as a transmission line, such as the input / output terminal 2020 shown at the top of FIG. .
- one mixing / distributing device 2024 by using one mixing / distributing device 2024, a plurality of, specifically, up to four transmitting / receiving devices 2014, 2014, ... can be connected.
- a plurality of two in FIG.
- Transmitter / receiver devices 2014, 2014,... can also be connected. Then, there may be a so-called empty terminal to which the transmitting / receiving device 2014 is not connected, such as the input / output terminal 2020 shown at the bottom in FIG.
- the mixing device 2024 has one primary terminal 2026 and four secondary terminals 2028, 2028,
- the signal input from the primary terminal 2026 is converted to each secondary terminal 2028, 2028,... , Or mix the signals input from the secondary terminals 2028, 2028,... And output from the primary terminal 2026. Therefore, the primary terminal 2026 is connected to the input / output terminal 2020 of the center device 2012 via the coaxial cable 2022, or to the secondary terminal 2028 of another mixing / distributing device 2024. Then, each secondary terminal 2028 is connected to the light transmitting / receiving device 2014 via the coaxial cable 2022, or is connected to the primary terminal 2026 of another mixing / distributing device 2024, or is made an empty terminal. .
- the coaxial cable 2022 is superimposed with DC power as a driving power supply for each of the light transmitting and receiving devices 2014, 2014,... Having the center device 2012 as a supply source, and the mixer / distributor 2024 converts this DC power into primary power.
- the terminal 2026 also has a function of transmitting the force to the secondary terminals 2028, 2028,.
- the mixer / distributor 2024 is installed, for example, behind a ceiling or behind a wall.
- the overall operation of the infrared conference system 2010 will be briefly described. For example, suppose that a speech request has been made by a certain terminal device 2018. This comment request is made by operating a comment request switch on an operation panel (not shown) provided in the terminal device 2018. Then, in the terminal device 2018, uplink control data indicating that a speech request has been made is generated. The uplink control data also incorporates an identification number indicating the request source of the comment request. The upstream control data is converted (frequency modulation) into an upstream FM signal having a predetermined reference frequency, and further, the upstream FM signal is converted (intensity modulation) into infrared light having a wavelength of 870 [nm]. Fired from the terminal device 2018. In order to emit the infrared rays, the terminal device 2018 includes a plurality of infrared light emitting diodes (LEDs) 2030 described later as light transmitting means.
- LEDs infrared light emitting diodes
- the upward infrared ray emitted from the terminal device 2018 is incident on an appropriate place, for example, the light transmitting / receiving device 2014 near the terminal device 2018.
- the transmitter / receiver 2014 includes a plurality of photodiodes (PD) 2040 (described later) as light receiving means for converting incident infrared light into electric signals, and further performs a tuning process on the converted electric signals. You.
- PD photodiodes
- an uplink FM signal is extracted.
- the extracted upstream FM signal is sent to the center device 2012 via the coaxial cable 2022 or additionally through one or more mixer / distributors 2024.
- the center device 2012 receives the upstream FM signal from which the power transmitting and receiving device 2014 Performs demodulation processing on the received upstream FM signal. As a result, the uplink control data is reproduced. Furthermore, the center device 2012 analyzes the reproduced uplink control data, and recognizes that the utterance request has been made and the terminal device 2018 that has requested the utterance request. Then, it generates downlink control data for permitting the terminal device 2018 to speak, and further converts the downlink control data into a downlink FM signal having a reference frequency different from the above uplink FM signal. This downlink FM signal is sent to all the light transmitting / receiving devices 2014, 2014,... Via the coaxial cable 2022 or, additionally, one or more mixing / distributing devices 2024.
- Each of the light transmitting and receiving devices 2014, 2014, ... includes a plurality of infrared light emitting diodes 2050, 2050, ... as described later, and according to the downlink FM signal sent from the center device 2012, The infrared light emitting diodes 2050, 2050, ... emit light. As a result, infrared light with a wavelength of 870 [nm] is emitted from each transmitter / receiver 2014, 2014, ... (infrared light emitting die 2050, 2050, ...;).
- Each terminal device 2018 includes a plurality of photodiodes 2060 described below for converting incident infrared rays into electric signals, and the electric signals converted by these photodiodes 2060, 2060,. Synchronization processing is performed. As a result, a downlink FM signal is extracted. Further, the terminal device 2018 performs demodulation processing on the extracted downlink FM signal to reproduce downlink control data. Then, it is determined whether the reproduced downlink control data is transmitted to itself or not, for example, whether or not the downlink control data incorporates its own identification number. Here, only the terminal device 2018 that has received the downlink control data sent to itself is allowed to speak, so to speak, is activated.
- the center device 2012 receives the uplink FM signal transmitted from the light transmission / reception device 2014, performs demodulation processing on the received uplink FM signal, and reproduces an audio signal.
- the reproduced voice signal is supplied to an external speed, not shown, connected to an external output terminal of the center device 2012. Thereby, the voice of the utterance source is reproduced. Further, the center device 2012 newly generates a downlink FM signal based on the reproduced audio signal.
- the down FM signal is sent to each of the light transmitting and receiving devices 2014, 2014,.
- Each of the light transmitting and receiving devices 2014, 2014, ... emits the above-mentioned infrared light emitting diodes 2050, 2050, ... in accordance with the supply of the downlink FM signal transmitted from the center device 2012.
- infrared light is emitted from each of the light transmitting / receiving devices 2014, 2014,... (infrared light emitting diodes 20 50, 2050, ⁇ ), and this downstream infrared light is incident on each terminal device 2018, 20 18,.... Is done.
- Each of the light transmitting and receiving devices 2014, 2014, ... converts incident infrared light into an electric signal, and performs a tuning process on the converted electric signal.
- a downlink FM signal is extracted.
- the terminal device 2018 performs demodulation processing on the extracted downlink FM signal to reproduce a voice signal.
- This audio signal is input to a monitor speaker (not shown) provided on the operation panel, thereby reproducing the voice of the utterance source. That is, each terminal device 2018 can monitor the voice of the utterance source.
- speech can be simultaneously made by up to four terminal devices 2018, 2018, .... That is, four channels are prepared as so-called uplink audio channels from the terminal devices 2018, 2018,... To the center device 2012 via the light transmitting / receiving devices 2014, 2014,.
- four channels, CHI, CH2, CH3, and CH4 are provided as uplink audio channels, and their reference frequencies (carrier frequencies) are 7.35 [MHz ], 8.10 [MHz ], 8.55 [MHz] and 9.15 [MHz].
- a control channel CHO dedicated to uplink control data is also provided. The reference frequency of this control channel CHO is 6.45 [MHz].
- two channels are prepared as so-called downlink channels from the center device 2012 to the terminal devices 2018, 2018, ... through the light transmitting / receiving devices 2014, 2014, ....
- channel CH1 is a channel for main audio
- channel CH2 is a channel for sub audio.
- the main audio channel CH1 is used preferentially
- the sub-audio channel CH2 is used, for example, when broadcasting simultaneous interpreted sounds.
- an external microphone power (not shown) connected to an external input terminal (not shown) of the center device 2012 is also input to the simultaneous interpretation sound.
- each terminal device 2018 is provided with a channel selection switch (not shown) for arbitrarily selecting one of the main audio channel CH1 and the sub audio channel CH2, Only the sound of the channel CH1 or CH2 selected by the channel selection switch (speech source sound or simultaneous interpretation sound) is reproduced on the terminal device 2018 side.
- a channel selection switch (not shown) for arbitrarily selecting one of the main audio channel CH1 and the sub audio channel CH2, Only the sound of the channel CH1 or CH2 selected by the channel selection switch (speech source sound or simultaneous interpretation sound) is reproduced on the terminal device 2018 side.
- Each of the downlink channels CH1 and CH2 is also used as a control channel for transmitting downlink control data.
- the downlink control data is transmitted via the downlink channel CH1 or CH2 while being mixed with the downlink audio signal.
- the downlink control data is superimposed on the audio signal by a subcarrier signal (subcarrier) having a frequency of 30 [kHz].
- a modulation method of the downlink control data for example, an FSK method is adopted.
- the control data transmitted by these downlink channels CH1 and CH2 may be the same or different.
- each of the light transmitting and receiving devices 2014 includes a plurality of infrared light emitting diodes 2050 as light transmitting means and a plurality of photodiodes 2040 as light receiving means. Specifically, as shown in Fig. 21, the transmitter / receiver 2014 , And 16 photodiodes 2050, 2050,..., And eight photodiodes 2040, 2040,.
- the communication area 2080 is composed of four areas 2082, 2082,... These areas 2082, 2082,... Are formed in directions different from each other by 90 degrees with respect to the light transmitting / receiving device 2014, and overlap each other so that no gap occurs.
- the infrared light emitting diodes 2050, 2050,... Correspond to the respective areas 2082, 2082,. Four pieces are allocated to each thread.
- the photodiodes 2040, 2040,... are also divided into two each of these four sets.
- the light transmitting and receiving device 2014 includes a disc-shaped base 2100.
- twelve infrared light emitting diodes 2050, 2050,. (At 30 degree intervals) and radially.
- the remaining four infrared light emitting diodes 2050, 2050,... are arranged at equal intervals (at 90 ° intervals) along the circumferential direction of the base 2100, and It is arranged so as to face away from the base 2100. That is, for each set of A—D, three infrared light emitting diodes 2050, 2050,...
- the light emitting diode 2050 is distributed. As can be seen from FIG. 23 (b), the infrared light emitting diodes 2050, 2050,... Arranged near the periphery of the base 2100, and the infrared light emitting diodes 2 050, 2050,... Are mounted on ⁇ IJ disc-shaped printed rooster boards 2102 and 2104, respectively.
- the infrared light emitting diodes 2050, 2050,... Arranged near the center (printed wiring board 2104) are mounted at an angle larger than that, for example, about 60 degrees with respect to the horizontal plane. With such a configuration, four areas 2082, 2082,... Of A to D shown in FIG. 22 described above are formed, and a light transmission area as a second communication area is strictly formed. [0135] On the other hand, the photodiodes 2040, 2040, ... are infrared light emitting diodes 2050, 2050, ...
- these two photodiodes 2040, 2040,... are allocated to each pair of A and D, and one of the two photodiodes 2040 and 2040 allocated to each pair is , Is responsible for the lower band side of the above-mentioned reception channels of CH0-CH4 (6.45 [MHz]-9.15 [MHz]), and is responsible for the higher band side of the reception frequency band. I do.
- the photodiodes 2040 and 2040 of each pair are arranged side by side with the respective light receiving surfaces 2042 and 2042 facing the same direction (a direction from the center of the base 2100 to the outside). .
- the photodiodes 2040, 2040,... are arranged with their light receiving surfaces 2042, 2042,.
- each of the photodiodes 2040, 2040,... Is a disk-shaped printed board different from the printed wiring boards 2102 and 2104 on which the infrared light emitting diodes 2050, 2050,. Mounted on wiring board 2106.
- These photodiodes 2040, 2040,... Are mounted at a certain angle, for example, about 40 degrees with respect to the horizontal plane. With such a configuration, four areas A to D shown in FIG. 22 are formed, and strictly speaking, a reception area as a first communication area is formed.
- the vertex angle ⁇ of the communication area 2080 in which the four areas 2082, 2082,...
- Each of the above-described printed wiring boards 2102, 2104, and 2106 is arranged on the base 2100 in a so-called three-story configuration, with the center of each being aligned with the center of the base 2100.
- a printed wiring board 2102 on which twelve infrared light-emitting diodes 2050, 2050,... Are mounted is located at a location on the first floor closest to the base 100.
- the base is located at a location corresponding to the second floor, and a printed wiring board on which four infrared light emitting diodes 2050, 2050,. 2104 force
- the base is located at the location on the third floor farthest from the base 2100.
- These printed wiring boards 21 02, 2104 and 1106 have different diameters. Is the largest The printed circuit board 2104 on the third floor has the smallest diameter. Then, the printed wiring boards 2102, 2104 and 2106 are fixed to a dome-shaped cover 2108 force base 2100 made of an infrared transmitting material so as to cover the printed wiring boards 2102, 2104 and 2106.
- each terminal device 2018 also includes a plurality of infrared light emitting diodes 2030 as light transmitting means and a plurality of photodiodes 2060 as light receiving means as described above. Specifically, as shown in FIG. 24, twelve infrared light emitting diodes 2030, 2090 and 2092 forming two communication areas 2090 and 2092 in front (to the left in FIG. 24) and above the terminal device 2018. 2030,... and six photo diodes 2060, 2060,....
- the terminal device 2018 includes a printed wiring board 2202 installed horizontally in the housing 2200, and the printed wiring board 2202 is positioned closer to the front (FIG. 25).
- the printed wiring board 2202 is positioned closer to the front (FIG. 25).
- six infrared light emitting diodes 2030, 2030,... are arranged in approximately one row along the horizontal direction (the front and back sides of the paper) in a state facing upward.
- the three photodiodes 2060, 2060, ... have their respective light receiving surfaces 2062, 2062, ... facing upward, and beside them. They are arranged in approximately one row along the direction.
- the rear side (the right side in FIG. 25) of the position where these six infrared light emitting diodes 2030, 2030,... And the three photodiodes 2060, 2060,.
- the other printed wiring board 2206 is connected to the printed wiring board 2202 perpendicularly and with the component surface 2208 facing forward.
- the remaining six infrared light emitting diodes 2030, 2030,... Are directed obliquely upward, for example, inclined about 30 degrees with respect to a horizontal plane. And are arranged in substantially one row along the horizontal direction.
- the remaining three photodiodes 2 060, 2060,... also have their respective light receiving surfaces 2062, 2062,. It is arranged in approximately one row along the horizontal direction while being tilted to the right.
- a front communication area 2090 and an upper communication area 2092 are formed.
- the printed wiring board 2206 placed vertically A communication area 2090 in front is formed by the mounted infrared light emitting diodes 2030, 2030, ... and the photodiodes 2060, 2060, ..., and the infrared light emitting diodes 2030, 2030 mounted on the printed wiring board 2202 placed horizontally.
- ... and photodiodes 2060, 2060, ... form an upper communication area 2092.
- the light transmitting areas 2090 and 2092 as the second communication area are formed by the infrared light emitting diodes 2030, 2030,..., And the first light transmitting areas 2060, 2060,.
- Light receiving areas 2090 and 2092 as communication areas are formed.
- the viewing angle ⁇ in the vertical direction of the front communication area 2090 is about 80 ° -90 °, and the viewing angle ⁇ of the upper communication area 2092 in the front-back direction is about 30 ° -50 °. ing.
- a communication area 2094 covering the terminal device 2018 from the front to the upper side is formed.
- a portion covering the infrared light emitting diodes 2030, 2030, ... and the photodiodes 2060, 2060, ... is formed of a window material 2210 formed of an infrared transmitting material.
- the light transmitting and receiving device 2014 has a terminal 2120 to which a coaxial cable 2022 is connected. That is, through this terminal 2120, a down FM signal and DC power as power supply power are input from the outside (the center device 2012), and an up FM signal is output to the outside.
- the DC power to which the external force is also input via the terminal 2120 is input to the power supply circuit 2124 via the low-pass filter 2122 for AC cut.
- the power supply circuit 2124 generates a plurality of types (voltage values) of a DC power supply voltage Vcc for driving each circuit in the light transmitting / receiving device 2014 based on the input DC power.
- the downlink FM signal is input to low-pass filter 2128 and high-pass filter 2130 via DC cut capacitor 2126.
- the cutoff frequency of the low-pass filter 2128 is set to a value higher than the upper limit frequency of the downstream channels CH1 and CH2 and lower than the lower limit frequency of the upstream channel CHO—CH4, for example, 2.70 [MHz].
- the cutoff frequency of the high-pass filter 2130 is The value is higher than the cutoff frequency of the one-pass filter 2128 and lower than the lower limit frequency of the upstream channel CHO-CH4, for example, 5.16 [MHz]. Therefore, the downstream FM signal input to the low-pass filter 2128 passes through the low-pass filter 2128 and is input to the RF amplifier circuit 2132. On the other hand, the downstream FM signal input to the high-pass filter 2130 does not pass through the high-pass filter 2130.
- the downstream FM signal input to the RF amplification circuit 2132 is amplified here, and then input to the light transmission circuit 2134.
- the light transmitting circuit 2134 has the infrared light emitting diodes 2050, 2050,... Described above, and causes the infrared light emitting diodes 2050, 2050,. That is, luminance modulation is performed. As a result, infrared light with a wavelength of 870 [nm] is emitted from 2050, 2050, ... from the infrared light emitting diode.
- the light transmitting / receiving device 2014 also includes a light receiving circuit 2136.
- the light receiving circuit 2136 has the photodiodes 2040, 2040,... Described above, and converts each terminal device 2018, 2018,. In addition to the conversion, this electric signal is tuned to extract the uplink FM signal.
- the extracted upstream FM signal is amplified by the RF amplifier circuit 2138, sent to the terminal 2120 via the high-pass filter 2130 and the capacitor 2126, and output from the terminal 2120 to the outside (the center device 2012).
- the upstream FM signal output from the high-pass filter 2130 is applied to the low-pass filter 2128.
- the cut-off frequency of the low-pass filter 2128 is determined by the lower-limit frequency of the upstream channels CH0 to CH4. It is set to a lower value. Therefore, the upstream FM signal input to the low-pass filter 2128 does not pass through the low-pass filter 2128 and is not input to the down-stream RF amplifier circuit 2132.
- Both the low-pass filter 2128 and the high-pass filter 2130 are high-order (multi-stage) filters. By providing a powerful high-order filter, the downstream FM signal and the upstream FM signal can be clearly distributed. For example, 200 [dB] t ⁇ , height, and CZN (Carrier / Noise) ratio can be obtained.
- the photodiodes 2040, 2040,... Of the light receiving circuit 2136 are as described above. In this manner, the forces assigned to each of the four sets A to D can be used to electrically enable or disable the functions of the photodiodes 2040, 2040,. For this reason, the light receiving circuit 2136 is configured as shown in FIG.
- the light receiving circuit 2136 has one photoelectric conversion circuit 2150, 2150,..., One for each photodiode 2040.
- These photoelectric conversion circuits 2150, 2150,... Are driven by supply of a DC power supply voltage Vcc, and the DC power supply voltage Vcc is supplied to light receiving power supply switches 2152, 2152,.
- Vcc DC power supply voltage
- the respective photoelectric conversion circuits 2150, 2150 are supplied to the respective photoelectric conversion circuits 2150, 2150,. Therefore, only the photoelectric conversion circuits 2150 and 2150 of the set in which the power switch for light reception 2152 is turned on are enabled, and more specifically, the infrared power received also extracts the upward FM signal.
- the photoelectric conversion circuits 2150 and 2150 in the set in which the light receiving power switch 2152 is turned off are invalidated.
- the upstream FM signal extracted by the activated photoelectric conversion circuits 2150, 2150, ... is input to an addition circuit 2154 as a synthesizing means, and more specifically, an input resistor 2156 constituting the addition circuit 2154. , 2156,... Are input to the inverting input terminal of the operational amplifier 2158.
- the inverting input terminal of the operational amplifier 2158 is connected to the output terminal of the operational amplifier 2158 via a feedback resistor 2160, and the non-inverting input terminal is connected to the ground potential. Therefore, from the adder circuit 2154 (the output terminal of the operational amplifier 2158), a signal that combines the uplink FM signals extracted by the enabled photoelectric conversion circuits 2150, 2150,... Is output. Then, this signal is input to the RF amplifier circuit 2138 in FIG. 26 as an output signal of the light receiving circuit 2136.
- the power switches 2152, 2152,... For light reception are manually turned ON / OFF, and are constituted by, for example, dip switches.
- the light receiving power supply switches 21 52, 2152,... are provided, for example, in the above-described base 2100, and are operated by an installer or the like when the light transmitting / receiving device 2014 is installed.
- each photoelectric conversion circuit 2150 the specific configuration of each photoelectric conversion circuit 2150 will be described in further detail. That is, as shown in FIG. 28, the power source terminal of the photodiode 2040 constituting the photoelectric conversion circuit 2150 is connected to the above-described light-receiving power switch 2152 (Vcc), The anode terminal of the photodiode 2040 is connected to the ground potential via the coil 2300. That is, when the light-receiving power switch 2152 is turned on, the DC power supply voltage Vcc is applied to the photodiode 2040 as a so-called reverse bias voltage. Note that a bypass capacitor 2302 connected between the power source terminal of the photodiode 2040 and the ground potential is provided near the photodiode 2040.
- the photodiode 2040 when the DC power supply voltage Vcc is applied to the photodiode 2040 (the light-receiving power switch 2152 is turned on), infrared rays are incident on the photodiode 2040. Then, the voltage of the anode terminal of the photodiode 2040 changes in accordance with the incident intensity of the infrared ray.
- the photodiode 2040 since the photodiode 2040 has a capacitance component including a junction capacitance, a parallel resonance circuit, that is, a tuning circuit 2304 is formed by the capacitance component and the inductance of the coil 2300.
- the tuning frequency (resonance frequency) of the tuning circuit 2304 is determined by the magnitude of the capacitance component and the inductance value of the coil 2300.
- the magnitude of the capacitance component is determined by the characteristics of the photodiode 2040, and thus the tuning frequency is determined by the inductance value of the coil 2300.
- one of the two photoelectric conversion circuits 2150 and 2150 for each pair is tuned to the lower side of the reception frequency band of the above-mentioned uplink channels CH0 to CH4, and the other is shifted to the higher side.
- the inductance value of the coil 2300 is determined so as to tune.
- the upstream FM signal extracted by the tuning circuit 2304 is input to the preamplifier circuit 2308 via the coupling 'capacitor 2306, and more specifically, the N-channel type of the preamplifier circuit 2308. Input to the gate terminal of FET (Field Effect Transistor) 2310.
- the preamplifier circuit 2308 is composed of an FET 2310, a bias resistor 2312 connected between the gate terminal of the FET 2310 and the ground potential, and a power supply resistor connected at one end to the drain terminal of the FET 2310.
- a resistor 2316 connected between the source terminal of the FET 2310 and the ground potential, and a bypass capacitor 2318 connected in parallel with the resistor 2316.
- the power for driving the preamplifier circuit 2308 is supplied to the preamplifier circuit 2320 via an emitter follower circuit 2320 and a high-frequency amplifier circuit 2322 which are subsequent circuits. Supplied at 08.
- the other end of the resistor 2314 serving as a power supply supply port is connected to the ground potential via a bypass capacitor 2324.
- the upstream FM signal amplified by the preamplifier circuit 2308 is input to the emitter follower circuit 2320 via the DC cut capacitor 2326, and more specifically, the base of the NPN transistor 2328 included in the emitter follower circuit 2320. Input to the terminal.
- the emitter follower circuit 2320 is composed of a transistor 2328 and an emitter grounding resistor 2330 having one end connected to the emitter terminal of the transistor 2328, and the preamplifier circuit 2308 receives the input upstream FM signal with a high input impedance. receive. That is, impedance conversion processing is performed.
- the upstream FM signal subjected to impedance conversion processing by the emitter follower circuit 2320 is input to the final stage high-frequency amplifier circuit 2322 via a DC cut capacitor 2332, and more specifically, the high-frequency amplifier circuit Input to the base terminal of NPN transistor 2334 which composes 2322.
- a DC bias voltage is applied to the base terminal of the transistor 2328 which is the input terminal of the emitter follower circuit 2320.
- the base terminal is connected to the light receiving power switch 2152 (Vcc) via the resistors 2336 and 2338, and is connected to the ground potential via the resistor 2340.
- power supply power for driving the emitter follower circuit 2320 is supplied to the emitter follower circuit 2320 via the high frequency amplifier circuit 2322. Therefore, the collector terminal of the transistor 2328 is connected to the emitter terminal of the transistor 2334. Further, the collector terminal of the transistor 2328 is connected to the ground potential via a capacitor 2342 for bypass.
- the high-frequency amplifier circuit 2322 has a transistor 2334, and a power supply resistor 2344 connected between the drain terminal of the transistor 2334 and the light-receiving power switch 2152 (Vcc).
- the interconnection point between the resistor 2344 and the power switch 2152 for light reception is connected to the ground potential via a capacitor 2346 for bypass.
- the three resistors 2336, 2338, and 2340 described above also function as a noisy resistor for applying a DC bias voltage to the base terminal of the transistor 2334.
- the three resistors 2336, 2338, and 2338 The base terminal is connected to the connection point.
- This high lap The upstream FM signal (the signal output from the collector terminal of the transistor 2334) after the amplification processing by the wave amplifier circuit 2322 is output as the output signal of the photoelectric conversion circuit 2150 via the DC cut capacitor 2348, and is output as shown in FIG. It is input to the addition circuit 2154.
- the photoelectric conversion circuit 2150 configured as described above, when the power supply switch for light reception 2152 is turned on, as shown by a dotted arrow 2350 in FIG.
- the current Is flows to the ground potential via the high-frequency amplifier circuit 2322, the emitter follower circuit 2320, and the preamplifier circuit 2308. Therefore, the high-frequency amplifier circuit 2322, the emitter follower circuit 2320, and the preamplifier circuit 2308 are driven by using the common DC current Is as a power supply.
- the voltage value of the DC power supply voltage Vcc is desirably set to a relatively high value, for example, about +15 [V]-+ 24 [V]. In this way, the drive current Is can be suppressed to about 1 [mA].
- the so-called high input impedance element FET2310 is employed for the preamplifier circuit 2308, and the upstream FM signal after the amplification processing by the preamplifier circuit 2308 is passed through an emitter follower circuit 2320 for impedance conversion.
- the amplification factor of the high-frequency amplifier circuit 2322 can be particularly increased.
- an extremely large amplification factor of, for example, about 50 [dB] can be obtained for the entire photoelectric conversion circuit 2150.
- the functions of the infrared light emitting diodes 2 050, 2050,. Can be electrically enabled or disabled. For this reason, the light transmitting circuit 2134 is configured as shown in FIG.
- the light transmitting circuit 2134 has one brightness modulation circuit 2170, 2170,..., One for each set of A to D.
- Each of these luminance modulation circuits 2170, 2170,... Has four infrared light emitting diodes 2050, 2050,.
- Each of the luminance modulation circuits 2170, 2170,... Is driven by the supply of a DC power supply voltage Vcc, and the DC power supply voltage Vcc is a light-transmitting power switch provided for each set of A to D. Are individually supplied to the respective luminance modulation circuits 2170, 2170,.
- the luminance modulation circuit 2170 of the set to which the light transmission power switch 2172 is turned on is enabled, and specifically, the respective infrared light emitting diodes 2050 according to the downlink FM signal input from the RF amplification circuit 2132. , 2050, ... to emit light.
- the luminance modulation circuit 2170 of the set in which the light transmission power switch 2172 is turned off is disabled.
- the power transmitting power switches 2172, 2172,... are also configured by the same as the light receiving power switches 2152, 2152,. These light transmitting power switches 2172, 2172,... are provided, for example, in the above-described base 2100, and are operated by an installer or the like when the light transmitting / receiving device 2014 is installed.
- each luminance modulation circuit 2170 has an operational amplifier 2360, an N-channel FET 2362, a resistor 2364, and a voltage-current conversion circuit 2366 which also has a power.
- the downstream FM signal amplified by the RF amplifier circuit 2132 is input to the non-inverting input terminal of the operational amplifier 2360.
- the output terminal of the operational amplifier 2360 is connected to the gate terminal of the FET2362, and the inverting input terminal of the operational amplifier 2360 is connected to the source terminal of the FET2362. This source terminal is connected to the ground potential via a resistor 2364.
- the four infrared light emitting diodes 2050, 2050, ... are connected in series to the drain terminal of the FET2362.
- the power source terminals of the series circuit of the four infrared light emitting diodes 2050, 2050, ... Side is connected.
- the anode terminal side of the series circuit of the infrared light emitting diodes 2050, 2050,... Is connected to the light transmitting power switch 2172 (Vcc), and is connected to the ground potential via the noisy capacitor 2368. Connected.
- a current lb corresponding to the signal level of the downstream FM signal input to the non-inverting input terminal of the operational amplifier 2360 flows forward to each of the infrared light emitting diodes 2050, 2050,. Then, when the current lb flows, each infrared light emitting diode 2050, 2050,... Emits light, so that the luminance is modulated. As a result, infrared rays according to the downlink FM signal are emitted from each infrared emitting diode 2050, 2050,...
- the infrared light emitting diodes 2050, 2050,... Is a non-linear element, which is not proportional, so that if the powerful infrared light emitting diodes 2050, 2050, ... are allowed to emit light in accordance with the signal level of the FM signal, an intermodulation product will occur, which may hinder infrared communication. There is. However, as the infrared light emitting diodes 2050, 2050, etc., those whose light emission output is proportional to the forward current lb, so-called linear characteristics, are used, and the down-converted FM signal is converted to a voltage-current conversion circuit as described above.
- the generation of the intermodulation product can be prevented, and comfortable infrared communication can be realized. can do.
- a series circuit of a resistor 2370 and a switch circuit 2372 is provided in parallel with resistor 2364.
- This switch circuit 2372 operates in conjunction with the operation of the light transmission power supply switches 2172, 2172,... Of the other luminance modulation circuits 2170, 2170,. Specifically, when one of the light transmission power switches 2172, 2172,... Of the other luminance modulation circuits 2170, 2170,... Is turned off, the switch circuit 2372 is turned on. As a result, the current lb flowing through the infrared light emitting diodes 2050, 2050,... Increases, and the intensity (energy) of infrared rays emitted from the infrared light emitting diodes 2050, 2050,.
- the terminal device 2018 includes a light receiving circuit 2220.
- the light receiving circuit 2220 is provided with the above-described photodiodes 2060, 2060,..., S.
- the light receiving circuit 2220 performs a tuning process on the electric signals converted by the photodiodes 2060, 2060,. And extract the downlink FM signal.
- the extracted downstream FM signal is input to the receiving circuit 2222, where it is converted into an intermediate frequency signal, and the intermediate frequency signal is subjected to demodulation processing. Thereby, the audio signal or the downlink control data is reproduced.
- the audio signal is input to a monitor speaker (not shown), and the downlink control data is input to the control circuit 2224.
- the control circuit 2224 has a CPU (Central Processing Unit). When the control circuit 2224 receives downlink control data as input, the control circuit 2224 analyzes the control data and controls the transmission circuit 2226 based on the analysis result. Then, for example, an up channel is selected.
- the control circuit 2224 The control panel 2224 is also connected to the control circuit 2224, and controls the transmission circuit 2226 or the reception circuit 2222 in response to the operation of the operation panel. Specifically, for example, when the above-mentioned channel selection switch is operated, the receiving channel by the receiving circuit 22 is controlled in response thereto, and when the above-mentioned speech request switch is operated, this is controlled. In response, it selects the uplink channel of transmission circuit 2226, generates uplink control data indicating that, and inputs it to transmission circuit 2226.
- a CPU Central Processing Unit
- Transmitting circuit 2226 generates an uplink FM signal based on control data input from control circuit 2224 or an audio signal input from microphone 2016. Then, the upward FM signal is input to the light transmission circuit 2228.
- the light transmitting circuit 2228 has the infrared light emitting diodes 2030, 2030,... Described above, and the transmitting circuit 2226 causes the infrared light emitting diodes 2030, 2030,. In other words, luminance modulation is applied. As a result, infrared light having a wavelength of 870 [nm] is emitted from the infrared light emitting diodes 2030, 2030,.
- Each circuit constituting the terminal device 2018 is driven by a battery (not shown) as a power supply.
- the photodiodes 2060, 2060, ... included in the light receiving circuit 2220 include a photodiode for forming the front communication area 2090 and a photodiode for forming the upper communication area 2092 as described above.
- Each of the three powers can be electrically enabled or disabled for each communication area 2090 and 2092 for each communication area, 2060, 2060, etc. .
- the light receiving circuit 2220 is configured as shown in FIG.
- the light receiving circuit 2220 has a photoelectric conversion circuit 2400 corresponding to the front communication area 2090 and a photoelectric conversion circuit 2402 corresponding to the upper communication area 2092. Since these photoelectric conversion circuits 2400 and 2402 have the same electrical configuration, only one of them, for example, the photoelectric conversion circuit 2400 will be described.
- the photoelectric conversion circuit 2400 (similarly for the photoelectric conversion circuit 2402) is driven by the supply of a DC power supply voltage Vcc using the above-described battery as a power supply. It is supplied to the photoelectric conversion circuit 2400. Therefore, the photoelectric conversion circuit 2400 is enabled only when the light-receiving power switch 2404 is turned on, and Physically, it extracts downstream FM signals from the received infrared light. On the other hand, when the light receiving power switch 2404 is turned off, the photoelectric conversion circuit 2400 is invalidated.
- the light-receiving power switch 2404 is also configured by a dip switch, for example, like the light-receiving power switch 2152, 2152,... However, the power switch 2404 for light reception in the terminal device 2018 is provided at a position where it can be operated by, for example, the operator of the infrared conference system 2010.
- the three photodiodes 2060, 2060,... Constituting the photoelectric conversion circuit 2400 are connected in parallel with each other, and the power source terminals of the photodiodes 2060, 2060,. Connected to switch 2404.
- the anode terminals of the photodiodes 2 060, 2060,... are connected to the ground potential via a coil 2406. That is, when the light-receiving power switch 2404 is turned on, the DC power supply voltage Vcc is applied as a reverse bias voltage to each of the photodiodes 2060, 2060,.
- a bypass capacitor 2408 is provided between the power source terminals of the photodiodes 2060, 2060,... And the ground potential.
- a tuning circuit 2410 is formed by the capacitance component of each of the capacitors 2060, 2060,... And the inductance of the coil 2406.
- the tuning frequency of the tuning circuit 2410 is determined by the inductance value of the coil 2406, for example, the center frequency (2.10 [MHz]).
- the tuning circuit 2410 has been subjected to a so-called Q dump process for flattening the sensitivity in the reception frequency band. Specifically, the anode terminal of each photodiode 2060, 2060,. A resistor 2412 for the Q dump process is provided between the two.
- the downlink FM signal extracted by the tuning circuit 2410 is input to a preamplifier circuit 2416 similar to the preamplifier circuit 2308 in Fig. 28 via a coupling capacitor 2414.
- the preamplifier circuit 2416 is composed of an N-channel type FET 2418, a bias resistor 2420 connected between the gate terminal of the FET 2418 and the ground potential, the drain terminal of the FET 2418 and the power supply for light reception described above.
- a power supply resistor 2422 connected to the switch 2404, a source grounding resistor 2424 connected between the source terminal of the FET 2418 and the ground potential, and a node connected in parallel with the resistor 2424.
- a capacitor 2426 for the optical path.
- the downstream FM signal amplified by the preamplifier circuit 2416 is input as an output signal of the photoelectric conversion circuit 2400 to a summing circuit 2430 as a synthesizing means via a DC cut capacitor 2428.
- the signal is input to the inverting input terminal of the operational amplifier 2434 via the input resistor 2432 included in the adding circuit 2430.
- the addition circuit 2430 (the output terminal of the operational amplifier 2434) outputs a combined signal of the downstream FM signal extracted by the enabled one of the photoelectric conversion circuits 2400 and 2402. Then, this signal is input to the receiving circuit 2222 in FIG. 31 as an output signal of the light receiving circuit 2220.
- the addition circuit 2430 has the same configuration as the addition circuit 2154 in FIG. 27 described above. Specifically, the inverting input terminal of the operational amplifier 2434 is connected to the output terminal of the operational amplifier 2434 via the feedback resistor 2436. The non-inverting input terminal is connected to the ground potential.
- the functions of the light emitting diodes 2030, 2030,. Can be disabled or disabled.
- the light transmitting circuit 2228 is configured as shown in FIG.
- the light transmission circuit 2228 has a luminance modulation circuit 2450 corresponding to the front communication area 2090 and a luminance modulation circuit 2452 corresponding to the upper communication area 2092. Since these luminance modulation circuits 2450 and 2452 have the same configuration electrically, only one of them, for example, the luminance modulation circuit 2450 will be described.
- Luminance modulation circuit 2450 (similar to luminance modulation circuit 2452) includes photoelectric conversion circuits 2400 and 2400. Similarly to 402, it is driven by the supply of the DC power supply voltage Vcc using the above-described battery as a power supply, and this DC power supply voltage Vcc is supplied to the luminance modulation circuit 2450 via the light transmission power switch 2454. Therefore, only when the light transmission power switch 2454 is ON, the luminance modulation circuit 2450 is enabled, and more specifically, each of the infrared light emitting diodes 2030, 2030 according to the upstream FM signal input from the transmission circuit 2226. , ... are emitted.
- the light-transmitting power switch 2454 is also configured by, for example, a dip switch arbitrarily operable by an operator, like the light-receiving power switch 2404.
- the luminance modulation circuit 2450 has the same configuration as the luminance modulation circuit 2170 of the light transmitting and receiving device 2014 shown in FIG. 30 described above, and includes an operational amplifier 2456, an N-channel type FET 2458, a resistor 2460, and a power supply. Having a voltage-current conversion circuit 2462. That is, the upstream FM signal from the transmission circuit 2226 is input to the non-inverting input terminal of the operational amplifier 2456. The output terminal of the operational amplifier 2456 is connected to the gate terminal of the FET 2458, and the inverting input terminal of the operational amplifier 2456 is connected to the source terminal of the FET 2458. This source terminal is connected to the ground potential via a resistor 2460.
- the six infrared light emitting diodes 2030, 2030,... are connected in series to the drain terminal of the FET2458. Specifically, the power source terminal side of the series circuit of the six infrared light emitting diodes 2030, 2030,. It is connected. The anode terminal side of the series circuit of the infrared light emitting diodes 2030, 2030,... Is connected to the light transmission power switch 2454 (Vcc) and to the ground potential via the binos capacitor 2463. .
- a current lb ′ corresponding to the signal level of the upstream FM signal input to the non-inverting input terminal of the operational amplifier 2456 flows forward to each of the infrared light emitting diodes 2030, 2030,. . Then, when the current lb 'flows, each of the infrared light emitting diodes 2030, 2030,... Emits light, so that the luminance is modulated. As a result, infrared rays according to the upward FM signal are emitted from the infrared emitting diodes 2030, 2030,...
- a parallel circuit is provided for resistor 2460, and a series circuit of resistor 2464 and switch circuit 2466 is provided.
- This switch circuit 2466 In conjunction with the operation of the light transmission power switch 2454 on the side of the luminance modulation circuit 2452 of FIG. Specifically, when the light transmission power switch 2454 of the other luminance modulation circuit 2452 is turned off, the switch circuit 2466 is turned on. As a result, the current lb flowing through the infrared light emitting diodes 2030, 2030,... Increases, and the intensity of infrared rays emitted from the infrared light emitting diodes 2030, 2030,.
- the infrared conference system 2010 of the fourth embodiment is used in a conference room where the plasma display device 2500 is installed. It is assumed that the power receiving switches 2 152, 2152,... For light reception described above are all turned on for all the light transmitting / receiving devices 2014, 2014,. In this case, some of the transmitter / receivers 2014 and 2014 (located at! / In Fig. 34 and the first and second from the left end) near the plasma display device 2500! Normal infrared communication may not be possible due to the influence of infrared rays emitted from the display 2500.
- the area 2082 on the side where the plasma display device 2500 is present is invalidated by operating the above-described power receiving switch 2152, respectively, so that FIG.
- the plasma display device 2500 can be removed from the communication areas 2080 and 2080 of the respective light transmitting and receiving devices 2014 and 2014. In this way, even in an environment where the plasma display device 2500 is installed, normal infrared communication can be performed without being affected by the infrared radiation emitted from the screen.
- each area 2082, 2082, ... stops the supply of the DC power supply voltage Vcc to the photoelectric conversion circuits 2150, 2150, ... forming the respective areas 2082, 2082, .... It is realized by. Therefore, one of the areas 2082 (the photoelectric conversion circuits 2150 and 21 When 50) is invalidated, the power consumption of the light transmitting / receiving device 2014 is reduced accordingly, and the power consumption of the entire infrared conference system 2010 is reduced accordingly.
- the infrared light receiving function in any of the areas 2082 is invalidated, the area 2082 is outside the communication target area. Therefore, it is not necessary to transmit the infrared light from the light transmitting / receiving device 2014 to such an area 2082. Therefore, it is desirable to operate the light transmission power supply switches 2172, 2172,... To stop the transmission of the downward infrared rays to the area 2082.
- the output intensity of the downstream infrared rays to the other areas 2082, 2082,... Increases as described above.
- the infrared radiation emitted from the plasma display device 2500 is regarded as noise
- the desired SZN (Signal / Noise) ratio of the infrared radiation (used for infrared communication) is improved, and the influence of the noise is reduced. It can be suppressed reliably.
- each terminal device 2018 also includes a front communication area 2090 and an upper communication area 2092. Then, the infrared light receiving function in each of these two communication areas 2090 and 2092 can be arbitrarily enabled or disabled by manual operation of the light receiving power supply switches 2404 and 2404 in a dip switch configuration. .
- the above-described light-receiving power switch 2404 By the operations of and 2404, it is possible to eliminate the influence of the infrared radiation radiated from the plasma display device 2500. More specifically, as shown in FIG. 37, for all terminal devices 2018, 2018,..., Only the upper communication area 2092, 2092,. , 2090,... Can be eliminated, the influence of the plasma display device 2500 irrespective of the position and orientation of each of the terminal devices 2018, 2018,. This also means that the position and orientation of each terminal device 2018, 2018,... Can be freely changed. That is, it is possible to freely lay out each terminal device 2018, 2018,... Without being limited by the presence of a noise source such as the plasma display device 2500. Therefore, terminal devices 2018, 2018 Even if the environment (for example, a conference room) where, ... is installed changes, it can easily cope with the change in the environment.
- the environment for example, a conference room
- invalidation of communication areas 2090 and 2092 is realized by stopping supply of DC power supply voltage Vcc to photoelectric conversion circuits 2400 and 2402 forming communication areas 2090 and 2092. Therefore, the power consumption of the terminal device 2018 is reduced accordingly. This is extremely effective for the terminal device 2018 driven by the knotter as a power source.
- each terminal device 2014 the transmission of upstream infrared rays to each of the communication areas 2090 and 2092 may be arbitrarily stopped, that is, manually stopped by the light transmission power switches 2454 and 2454. Can be. Then, when the transmission of the upstream infrared ray to one of the communication areas 2090 or 2092 is stopped, the output intensity of the upstream infrared ray to the other communication area 2092 or 2090 increases. Accordingly, the SZN ratio of the upward infrared ray is improved accordingly, and the effect of the infrared ray as noise radiated from the plasma display device 2500 is further reduced.
- the areas 2082, 2082, ... for transmitting infrared rays can be limited by manual operation using the light transmitting power switches 2172, 2172, ....
- the areas 2082, 2082,... For transmitting infrared rays are restricted in this way, the output intensity of infrared rays to the remaining (effective) areas 2082, 2082,.
- the areas 2090 and 2092 to which infrared light is transmitted can be limited by manual operation using the light transmission power switches 2454 and 2454. .
- the infrared light transmission area 2090 or 2092 When the infrared light transmission area 2090 or 2092 is limited in this way, the output intensity of infrared light to the remaining light transmission area 2092 or 2090 increases. Therefore, it is less susceptible to the effects of noise! And comfortable infrared communication can be performed.
- the infrared conference system 2010 has been described as an example, but the present invention is not limited to this.
- the same technology as in the fourth embodiment may be applied to a simplex device, or the same technology may be applied to a light receiving device that only receives infrared rays unilaterally.
- the operations of the light receiving power switches 2152, 2152,... And the light transmitting power switches 2172, 2172,. Then, the light receiving power switches 2404 and 2404 and the light transmitting power switches 2454 and 2454 of the respective terminal devices 2018 may also be remotely controlled from the center device 2012 side.
- the light transmitting power switches 2172, 2172, ... may be turned ONZOFF in conjunction with the operation of the light receiving power switches 2152, 2152, .... Specifically, when one of the light receiving power switches 2152 is turned off and the corresponding area 2082 is invalidated, the light transmitting power switch 2172 corresponding to the invalidated area 2082 is turned off. You can do it!
- the light-transmitting power switches 2454 and 2454 may be turned ONZ in conjunction with the operation of the light-receiving power switches 2404 and 2404. That is, when one of the light receiving power switches 2404 is turned off and the corresponding communication area 2090 or 2092 is invalidated, the light transmitting power switch 2454 corresponding to the invalidated communication area 2090 or 2092 is activated. It may be turned off!
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- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Computing Systems (AREA)
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Optical Communication System (AREA)
- Light Receiving Elements (AREA)
Abstract
Description
Claims
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE602005016092T DE602005016092D1 (de) | 2004-03-25 | 2005-03-25 | Infrarot-kommunikationseinheit zur übertragungsweiterleitung zwischen einer haupteinheit und einem endgerät |
EP05721473A EP1732248B1 (en) | 2004-03-25 | 2005-03-25 | Infrared communication unit for relaying between a main unit and a terminal unit |
Applications Claiming Priority (6)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2004-089904 | 2004-03-25 | ||
JP2004089904A JP4025743B2 (ja) | 2004-03-25 | 2004-03-25 | 赤外線通信装置 |
JP2004-142447 | 2004-05-12 | ||
JP2004-142446 | 2004-05-12 | ||
JP2004142446A JP4044911B2 (ja) | 2004-05-12 | 2004-05-12 | 受光器 |
JP2004142447A JP4025750B2 (ja) | 2004-05-12 | 2004-05-12 | 赤外線通信装置 |
Publications (1)
Publication Number | Publication Date |
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WO2005093974A1 true WO2005093974A1 (ja) | 2005-10-06 |
Family
ID=35056535
Family Applications (1)
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PCT/JP2005/005496 WO2005093974A1 (ja) | 2004-03-25 | 2005-03-25 | 受光器および赤外線通信装置 |
Country Status (3)
Country | Link |
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EP (1) | EP1732248B1 (ja) |
DE (1) | DE602005016092D1 (ja) |
WO (1) | WO2005093974A1 (ja) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN112259275A (zh) * | 2020-10-19 | 2021-01-22 | 中国核动力研究设计院 | 一种电磁屏蔽环境下通信系统及通信方法 |
CN113740878A (zh) * | 2021-09-09 | 2021-12-03 | 南京牧镭激光科技有限公司 | 用于测风雷达的新型平衡探测器电路 |
Families Citing this family (3)
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JP5842090B2 (ja) | 2010-08-25 | 2016-01-13 | パナソニックIpマネジメント株式会社 | 照明光通信装置 |
RU2731528C1 (ru) * | 2020-02-19 | 2020-09-03 | Федеральное государственное бюджетное образовательное учреждение высшего образования "Юго-Западный государственный университет" (ЮЗГУ) | Устройство для приема, усиления, предварительной обработки сигналов оптических каналов передачи данных в инфракрасном диапазоне |
RU2757375C1 (ru) * | 2021-02-25 | 2021-10-14 | Федеральное государственное бюджетное образовательное учреждение высшего образования «Юго-Западный государственный университет» (ЮЗГУ) (RU) | Устройство для приема, усиления, предварительной обработки сигналов оптических каналов передачи данных в инфракрасном диапазоне |
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CN113740878A (zh) * | 2021-09-09 | 2021-12-03 | 南京牧镭激光科技有限公司 | 用于测风雷达的新型平衡探测器电路 |
CN113740878B (zh) * | 2021-09-09 | 2023-09-22 | 南京牧镭激光科技股份有限公司 | 用于测风雷达的平衡探测器电路 |
Also Published As
Publication number | Publication date |
---|---|
DE602005016092D1 (de) | 2009-10-01 |
EP1732248A4 (en) | 2008-01-02 |
EP1732248A1 (en) | 2006-12-13 |
EP1732248B1 (en) | 2009-08-19 |
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