JPH0821901B2 - Optical communication device in audiovisual equipment - Google Patents

Description

The present invention relates to an optical communication device in an audiovisual device, and more particularly to a device for wirelessly transmitting an optical signal.

(Prior Art) In conventional audiovisual (AV) equipment,
A wired system using a coaxial cable is used to connect the video player and the television (TV) receiver. In this wired system, the signal recorded on a video tape or video disc in a video player is read electromagnetically or optically and converted into an electrical video and audio signal, and this electrical video and audio signal is unchanged. Video and audio are played back by the coaxial cable to the TV receiver.

However, in the above-mentioned conventional wired system, when the installation location of the AV device is changed, it is necessary to re-route the cable, which is expensive and the cable is very unsightly.

Therefore, it is conceivable to adopt a cordless or wireless system for signal transmission from the video player to the TV receiver. The wireless system allows you to freely install AV equipment, which is convenient and looks good.

However, if radio waves are used for signal transmission in the wireless system, there is a risk that radio waves may be disturbed or the regulations of the Radio Law may be violated.

Therefore, a device that utilizes infrared rays, which is a type of light, for signal transmission has been proposed. Conventionally, an optical communication device in an audiovisual device of this type has a light emitting unit of an optical signal transmitter on the video player side. It has one light emitting element, for example a light emitting diode, and a condenser lens for condensing the light emitted from this light emitting element, and the light receiving portion of the optical signal receiver on the TV receiver side is a light receiving element, for example a photodiode. And a convex lens for condensing the light transmitted from the optical signal transmitter on the light receiving element. This convex lens is a so-called parallel lens that makes an incident light beam a parallel light beam and emits it, and the range of the incident angle was narrow.

However, in this conventional structure, it was difficult to achieve both easy alignment of the optical axis when installing the transceiver and improvement of efficiency in optical signal transmission. That is, in order to improve the efficiency of optical signal transmission, it is better to reduce the emission angle of light from the optical signal transmitter, but the smaller the emission angle of this light, the more difficult the optical axis alignment becomes. . Also, in the optical signal receiver, since a convex lens with a narrow incident angle range is used to collect light on the light receiving element, the light collecting position is likely to shift, and the restrictions on the installation of the transceiver become large and the optical axis Matching was even more difficult.

(Problems to be Solved by the Invention) As described above, conventionally, since the wired system is used for signal transmission from the video player to the TV receiver, there is a problem that it is difficult to change the installation location. Further, even if it is a wireless system, if radio waves are used for signal transmission, there is a risk of radio wave interference. further,
Even if light is used for signal transmission, conventionally, the light emitting part of the optical signal transmitter has only one light emitting element combined with the condensing lens, which facilitates alignment of the optical axis during installation. There is a problem that it is difficult to achieve both the improvement of the efficiency in the transmission of the optical signal, and since the optical signal receiver uses the convex lens with a narrow incident angle range, the optical axis alignment becomes more difficult. There was a problem.

The present invention is intended to solve the above-described problems, and in an audiovisual device, by utilizing light for signal transmission from the video player side to the TV receiver side, the video player and the TV receiver are It can be installed freely and looks good, it can prevent radio wave interference, it can improve the efficiency of optical signal transmission, and it can be used for optical axis alignment when installing transceivers. The purpose is to make it easy.

[Structure of Invention]

(Means for Solving the Problem) In order to achieve the above-mentioned object, an optical communication device in an audiovisual apparatus according to the present invention converts an electrical video and audio signal output from a video player into light, for example, infrared light. And an optical signal transmitter for wireless transmission,
An optical signal receiver for receiving the light transmitted from the optical signal transmitter, returning it to an electrical video and audio signal again and outputting it to a television receiver, and the optical signal transmitter further comprises a light emitting section. As a main light emitting element, a condenser lens for condensing light emitted from the main light emitting element, and a light from the condenser lens that is arranged so as to surround the optical axes of the main light emitting element and the condenser lens. The optical signal receiver has a plurality of sub-light emitting elements that emit light in substantially the same direction and in a wider range, and the optical signal receiver serves as a light receiving unit and a light transmitted from the optical signal transmitter. And a dome lens having a wide incident angle range for refracting and condensing the light toward the light receiving element.

(Operation) In the optical communication device in the audiovisual equipment of the present invention, the optical signal transmitter converts the electrical video and audio signals output from the video player into light and transmits the light wirelessly. At the same time, the optical signal receiver receives the light transmitted from the optical signal transmitter, restores the electrical video and audio signals again, and outputs them to the television receiver.
Then, this television receiver reproduces video and audio. At this time, the light emitted from the main light emitting element of the light emitting section of the optical signal transmitter is condensed by the condenser lens,
The light from this condensing lens is refracted toward the light receiving element by the dome lens of the light receiving part of the optical signal receiver, and is received by this light receiving element. The light is transmitted from the optical signal transmitter by the condensing lens. The directivity can be improved, and the efficiency of optical signal transmission can be improved. At the same time, since the lens of the light receiving portion of the optical signal receiver is a dome lens with a wide range of incident angles, even if the incident angle of the light receiving portion of the optical signal receiver with respect to the optical axis is large, The light is surely focused on the light receiving element. Also, when aligning the optical axes of the light emitting section of the optical signal transmitter and the light receiving section of the optical signal receiver when installing the transceiver, change the angular relationship of the transceiver while looking at the television receiver, for example. Perform a search. At this time, in the light emitting section of the optical signal transmitter, the plurality of sub light emitting elements arranged so as to surround the optical axis of the main light emitting element and the condenser lens are arranged in the same direction as the light from the condenser lens and in a wider range. By emitting light to the first, rough alignment of the optical axis can be easily performed. Then, it may be adjusted so that the light from the condenser lens is received by the light receiving element of the optical signal receiver.

(Embodiment) Hereinafter, a configuration of an embodiment of an optical communication device in an audiovisual apparatus of the present invention will be described with reference to the drawings.

In FIG. 1, reference numeral 1 denotes a video player, which drives a record carrier such as a video tape or a video disk, reads a signal recorded on the record carrier electromagnetically or optically, and electrically. It is converted into video and audio signals and output.

Reference numeral 2 denotes a television (TV) receiver including a speaker, and the TV receiver 2 reproduces video and audio with respect to the electrical video and audio signals output from the video player 1. Is.

Furthermore, 3 is an optical signal transmitter, and this optical signal transmitter 3
Is for converting the electric image and audio signals output from the video player 1 into infrared rays, which is a type of light, and transmitting the signals wirelessly. The optical signal transmitter 3
Has a power cord 5 which is detachably connected to the video player 1 by a cable 4 and which is connected to a 100V AC power source in order to input the video and audio signals from the video player 1. .

Further, 6 is an optical signal receiver, and this optical signal receiver 6 is
It receives the light transmitted from the optical signal transmitter 3, restores it to an electric video and audio signal again, and outputs it to the TV receiver 2. The TV receiver 2 and cables 7 and 8 can be attached and detached. It is connected to the.

Next, the configuration of the light emitting unit 10 of the optical signal transmitter 3 will be described below.
It will be described with reference to the drawings.

Reference numeral 11 denotes a cylindrical holder made of synthetic resin. At the rear end of the holder 11, one high-intensity infrared light emitting diode (LED) 13 mounted on a printed circuit board 12 is provided as a main light emitting element. Has been done. Further, at the front end portion inside the holder 11, a condenser lens 14 formed of a biconvex lens for condensing infrared rays emitted forward from the infrared LED 13 is attached. The diameter of the condenser lens 14 is, for example, 30
mm. Then, infrared rays are emitted forward from the condenser lens 14 within an angle range of about 5 to 10 °. Further, on the holder 11 and the outer peripheral side front end portion,
A printed circuit board 15 is attached with screws 16, and six infrared LEDs 1 as sub-light emitting elements are attached to the printed circuit board 15.
7 are mounted at equal intervals. These infrared LEDs 17 are arranged on the circumference centered on the optical axes of the infrared LEDs 13 and the lens 14, and emit infrared rays forward in the range of an angle of about 15 to 20 °. The lens
14 and infrared LED 17 are filters 1 made of synthetic resin
It is covered from the front by 8.

Next, the configuration of the light receiving section 20 of the optical signal receiver 6
It will be described with reference to the drawings.

Reference numeral 21 denotes a case, and a lens holder 22 made of synthetic resin is attached to the outer shell of the case 21 with a screw 23, and a dome lens 24 for condensing light is attached to the lens holder 22.
Is held. A printed circuit board 25 is arranged in the case 21, and a pin photodiode 26 as a light receiving element is mounted on the printed circuit board 25.
The pin photodiode 26 is located on the optical axis behind the dome lens 24. The dome lens 24, which is a substantially hemispherical lens, receives the infrared light transmitted from the optical signal transmitter 3 by the pin photodiode 26.
It refracts toward, but the range of the incident angle is very wide. The dome lens 24 is covered from the front by a filter 27 made of synthetic resin.

Next, the electrical configuration of the optical signal transmitter 3 will be described with reference to the block diagram of FIG.

In the figure, 31 is an NTSC video signal input terminal, and this input terminal 31 inputs a video signal from the video player 1, that is, a video signal including a sync signal. Also, 32 is a low pass filter, 33 is a clamp circuit, 34 is a pre-emphasis circuit, 35 is a deviation adjustment circuit, 36 is a white clip circuit, 37 is a modulation circuit, 38 is a sync signal separation circuit, and 39 is a carrier adjustment circuit. The circuit, 40 is an LED drive circuit.

Here, the low-pass filter 32 transmits a frequency band (0 to 5 MHz) required as a video signal to the next block and cuts frequencies of 5 MHz or higher to reduce noise and the like. Clamp circuit
33 is for keeping the DC component of the video signal at a constant voltage. The pre-emphasis circuit 34 emphasizes a high frequency component of the video signal, and improves the S / N ratio by performing de-emphasis on the receiving side later. The deviation adjustment circuit 35 adjusts the frequency deviation for performing frequency modulation. The white clip circuit 36 adjusts the image white level. The modulation circuit 37 frequency-modulates (FM) the video signal. Sync signal separation circuit
38 is for separating the horizontal synchronizing signal from the video signal. The carrier adjust circuit 39 adjusts the fundamental frequency for frequency modulation. LED drive circuit 4
0 is to amplify the modulated signal and drive the infrared LEDs 13 and 17.

Further, 41 is an audio input terminal of the first channel (CH.1), and this audio input terminal 41 is for inputting a CH.1 audio signal from the video player 1. Furthermore, 42 is a low pass filter, 43 is an auto gain control circuit, 44 is a noise reduction compressor, 45 is a pre-emphasis circuit, 46 is a limiter,
47 is a modulation circuit, 48 is a bandpass filter, 49 is a deviation adjustment circuit, and 50 is a carrier adjustment circuit. In addition, 51 is an LED drive circuit.
The drive circuit 51 drives the infrared LEDs 13 and 17.

Here, the auto gain control circuit 43 automatically adjusts the gain. The noise reduction compressor 44 is for reducing noise.

Further, 52 is an audio input terminal of the second channel (CH.2), and the audio input terminal 52 is for inputting the audio signal of CH.2 from the video player 1. In addition, this CH.2 audio input terminal 52 and infrared LED 13,17
The circuit provided between and is almost the same as the circuit provided between the audio input terminal 41 of the CH.1 and the infrared LEDs 13 and 17. Therefore, details are omitted in the drawing.

The infrared LEDs 13 and 17 use a DC power source ( _Vcc ) as a power source and emit infrared rays having a wavelength of 890 nm.

Next, the electrical configuration of the optical signal receiver 6 will be described with reference to the block diagram of FIG.

A resistor 60 and the pin photodiode 26 are connected in series between both poles of the DC power source, and a preamplifier 61 is connected to an intermediate point between the resistor 60 and the pin photodiode 26. Further, 62 is a limiter, 63 is a demodulation circuit, 64
Is a low-pass filter, 65 is a de-emphasis circuit, 66
Is a high pass filter and 67 is a video amplifier. Furthermore, 68 is an NTSC video signal output terminal, and this output terminal 68
Outputs a video signal to the TV receiver 2.

Here, the preamplifier 61 amplifies the electrical modulation signal generated by the light received by the pin photodiode 26. The limiter 62 adjusts the level of the amplified signal to an appropriate value. The demodulation circuit 63 demodulates the frequency-modulated signal and restores the original signal. The low pass filter 64 cuts off high frequency components of the demodulated signal. The de-emphasis circuit 65 restores the pre-emphasis circuit 34 on the transmitting side because the pre-emphasis circuit 34 emphasizes the video signal. The high-pass filter 66 cuts off excess low-frequency components of the video signal. The video amplifier 67 amplifies the video signal and adjusts it to a level connectable to the TV receiver 2.

71 is a bandpass filter, 72 is a limiter,
73 is a demodulation circuit, 74 is a low-pass filter, 75 is a de-emphasis circuit, 76 is a noise reduction expander, 77 is a mute circuit, and 78 is an audio amplifier. Further, 79 is a CH.1 audio output terminal, and this audio output terminal 79 outputs a CH.1 audio signal to the TV receiver 2.

Where noise reduction expander 76
Is for reducing noise. The audio amplifier 78 amplifies the audio signal and adjusts it to a level connectable to the TV receiver 2.

Further, 80 is a CH.2 audio output terminal, and the audio output terminal 80 outputs a CH.2 audio signal to the TV receiver 2. The circuit provided between the preamplifier 61 and the CH.2 audio output terminal 80 is the same as the circuit provided between the preamplifier 61 and the CH.1 audio output terminal 79. Therefore, details are omitted in the drawing.

An example of specifications of the transceivers 3 and 6 is as follows. That is, the possible distance between the transceivers 3 and 6 is 0 to 1
0m, possible reception angle is 5-10 °, depending on distance. The angle between the transceivers 3 and 6 can be adjusted during installation. The reception sensitivity is 50 dB or more. Further, the input / output terminals 31, 41, 52, 68, 79, 80 can be of a switching system between a pin jack and a BCN connector, for example. Also, the outline dimensions of transceivers 3 and 6 are 150 mm x 120 m.
It is about m × 60 mm.

 Next, the operation of the above embodiment will be described.

First, the optical signal transmitter 3 converts the electrical video and audio signals output from the video player 1 into infrared rays and wirelessly transmits them. That is, with the configuration shown in FIG. 4, the video and audio signals are modulated, and the electric signal is converted into infrared rays by the infrared LED 13, and the infrared rays from the infrared LED 13 are collected by the condenser lens 14. It is emitted while being illuminated. The same signal is transmitted from the other infrared LEDs 17 as well.

Further, the optical signal receiver 6 receives the infrared rays transmitted from the optical signal transmitter 3, restores them to electrical video and audio signals again, and outputs them to the TV receiver 2. That is, the infrared rays from the condenser lens 14 of the optical signal transmitter 3 are refracted and condensed by the dome lens 24 toward the pin photodiode 26,
The pin photodiode 26 receives the light, converts it into an electric signal, and further demodulates it by the structure shown in FIG. 5 to output the electric video and audio signals to the TV receiver 2. It

Then, the TV receiver 2 reproduces video and audio based on the electrical video and audio signals.

According to the above configuration, a cable for transmitting a signal from the video player 1 to the TV receiver 2 is unnecessary, so that AV equipment can be freely installed without being restricted by this cable, which is convenient. Therefore, changing the installation location of the AV device can be easily performed without much cost. Along with this, it also looks better.

In addition, since infrared rays, which is a kind of light, is used for signal transmission, there is no risk of violating the regulations of the Radio Law and no interference with radio waves. That is, various devices related to radio waves are not disturbed. In addition, as a signal transmission medium, infrared rays are excellent in that they have a short wavelength, a strong straight-line property, and a strong directivity.

Further, in the signal transmission, the directivity of the transmission from the optical signal transmitter 3 is enhanced by the condensing by the condensing lens 14, and the S / N ratio of, for example, 50 dB or more can be obtained. In this way, the efficiency of optical signal transmission can be improved.

The infrared LED 17 in the peripheral part of the light emitting unit 10 of the optical signal transmitter 3 can also transmit and receive between the transceivers 3 and 6, but the S / N ratio obtained by the infrared LED 17 in the peripheral part is 40.
~ 50 dB or less.

Further, in the optical signal receiver 6, since the lens for focusing on the pin photodiode 26 is the dome lens 24 having a wide incident angle range, the incident angle with respect to the optical axis of the light receiving unit 20 of the optical signal receiver 6 is Even if it is large, the infrared light from the optical signal transmitter 3 is reliably focused on the pin photodiode 26. That is, even if the optical axis of the light emitting unit 10 of the optical signal transmitter 3 is angularly displaced from the optical axis of the light receiving unit 20 of the optical signal receiver 6,
The condensing position by the dome lens 24 is kept substantially constant at the position of the pin photodiode 26, and the pin photodiode 26 reliably receives light.

As a result, the permissible range of the installation positions of the transceivers 3 and 6 is increased, and the transceivers 3 and 6 can be easily installed.

By the way, when the transceivers 3 and 6 are installed, the light emitting section 10 of the optical signal transmitter 3 and the light receiving section 20 of the optical signal receiver 6 are installed.
When aligning the optical axes of, while looking at the TV receiver 2, the search is performed by changing the angular relationship between the transceivers 3 and 6. That is, the angle relationship between the transmitters / receivers 3 and 6 is adjusted so that the image of the TV receiver 2 becomes as sharp as possible and the color thereof is sufficiently displayed.

At this time, the infrared LED 13
And the plurality of infrared LEDs 17 arranged around the optical axis of the condenser lens 14 radiate infrared rays in the same direction as the infrared ray from the condenser lens 14 and in a wider range, so that a rough optical axis is obtained. Matching is easy. Then, it may be adjusted so that the infrared light from the condenser lens 14 is received by the pin photodiode 26 of the optical signal receiver 6. That is, in the adjustment of the angular relationship between the transmitters / receivers 3 and 6, the infrared light from the infrared LED 17 is received by the pin photodiode 26, and the central portion of the position where an image appears on the TV receiver 2 from the condenser lens 14. The infrared light is received by the pin photodiode 26 of the optical signal receiver 6, and a clear image can be obtained.

Thus, according to the above configuration, in the light emitting section 10 of the optical signal transmitter 3, the infrared LE combined with the condenser lens 14 is combined.
In addition to D13, by providing a plurality of infrared LEDs 17 having a larger radiation range, it is possible to improve the efficiency in the transmission of infrared signals, and at the same time, the optical signal receiver 6 collects light on the pin photodiode 26. Combined with the fact that the lens is the dome lens 21 having a wide incident angle range, the optical axes can be easily aligned when the transceivers 3 and 6 are installed.

Moreover, since a plurality of infrared LEDs 17, which are sub-light emitting elements, are not combined with a condenser lens, the cost can be reduced.

〔The invention's effect〕

According to the present invention, an optical signal transmitter for converting an electric video and audio signal output from a video player into light and wirelessly transmitting the same, and a light signal transmitter for receiving the light transmitted from the optical signal transmitter and again receiving the light. Since it is provided with an optical signal receiver for returning to an electric video and audio signal and outputting it to a television receiver, the audiovisual equipment can be freely installed and the appearance is improved. At the same time, the use of light for signal transmission does not cause radio interference. The light emitting unit of the optical signal transmitter includes a main light emitting element, a condenser lens that collects light from the main light emitting element,
Since the main light-emitting element and the plurality of sub-light-emitting elements that surround the optical axis of the condenser lens and emit light in a wider range in substantially the same direction as the light from the condenser lens, the optical signal It is possible to both improve the efficiency of the transmission of data and to facilitate the optical axis alignment when the transceiver is installed. Furthermore, since the light receiving section of the optical signal receiver has a dome lens with a wide range of incident angle for refracting and condensing the light from the optical signal transmitter toward the light receiving element, The permissible range is increased, the transceiver can be installed easily, and the optical axis alignment becomes even easier.

[Brief description of drawings]

The drawings show an embodiment of an optical communication device in an audiovisual apparatus of the present invention. FIG. 1 is a perspective view of the whole, FIG. 2 (a) is a side view of a light emitting portion of an optical signal transmitter, and FIG. FIG. 3B is a front view of the same light emitting unit, FIG. 3 is a side view of the light receiving unit of the optical signal receiver, FIG. 4 is a block diagram showing the electrical configuration of the optical signal transmitter, and FIG. It is a block diagram which shows the electric constitution of a receiver. 1 ... video player, 2 ... television receiver,
3 ... Optical signal transmitter, 6 ... Optical signal receiver, 10 ... Light emitting section, 13 ... Infrared light emitting diode as main light emitting element,
14 ... Condensing lens, 17 ... Infrared light emitting diode as a sub-light emitting element, 20 ... Light receiving part, 24 ... Dome lens, 26
...... Pin photodiode as a light receiving element.

Claims (1)

[Claims] 1. An optical signal transmitter for converting electrical video and audio signals output from a video player into light and transmitting the light wirelessly; and a light transmitted from the optical signal transmitter for receiving electric light again. An optical signal receiver for returning to a television receiver to restore a typical video and audio signal, wherein the optical signal transmitter, as a light emitting unit, collects a main light emitting element and light emitted from the main light emitting element. A light-collecting lens and a plurality of sub-light-emitting elements which are arranged so as to surround the optical axes of the main light-emitting element and the light-collecting lens, and emit light in the same direction as the light from the light-collecting lens and in a wider range. The optical signal receiver includes a light receiving element as a light receiving portion, and a dome lens having a wide incident angle range for refracting and condensing the light transmitted from the optical signal transmitter toward the light receiving element. And having Optical communication equipment in the audiovisual equipment.