JPH0479528A - Optical communication equipment in audio visual equipment - Google Patents

Abstract

PURPOSE:To improve the transmission efficiency of an optical signal and to facilitate the alignment of optical axes at the installation of a transmitter-receiver by utilizing a light for signal transmission from a video player to a television receiver. CONSTITUTION:An optical signal transmitter 3 converts an electric video signal and audio signal outputted from a video player 1 into a light and sends it in a radio wave. Thus, an optical signal receiver 6 receives a light sent from the optical signal transmitter 3 and restores the light into the electric video signal and audio signal again and outputs it to a television receiver 2. Then the television receiver 2 regenerates the electric video signal and audio signal. In this case, a light radiating from the main light emitting element 13 of a light emitting section 14 of the optical signal transmitter 3 is collected by a condenser lens 14 and the light from the condenser lens 14 is refracted toward a light receiving element 26 by the dome lens 24 of a light receiving section 20 and received by the light receiving element 26 and the directivity of the transmission from the optical signal transmitter 3 is enhanced by the line collection by the condenser lens 14. Thus, the optical axis is aligned easily at the installation of the transmitter-receiver and the transmission efficiency of the optical signal is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to an optical communication device for audiovisual equipment, and particularly to one that wirelessly transmits optical signals.

(Prior Art) In conventional audiovisual (AV) equipment, a wired system using a coaxial cable is used to connect a video player and a television (TV) receiver. In this wired system, signals recorded on video tapes or video discs are read electromagnetically or optically by the video player and converted into electrical video and audio signals, and these electrical video and audio signals are converted as they are. The video and audio are transmitted to a TV receiver via a coaxial cable and played back.

However, with the conventional wired system, if the AV equipment is installed in a different location, the cables must be rewired, which is costly and also causes problems in that the cables are very unsightly.

Therefore, it is conceivable to adopt a cordless or wireless system for signal transmission from the video player to the TV receiver. If you use a wireless system, you can freely install AV equipment, making it more convenient and also improving the visual quality.

However, in a wireless system, if radio waves are used to transmit signals, there is a risk of interference with the radio waves or violation of regulations under the Radio Law.

Therefore, devices that use infrared rays, a type of light, have been proposed for signal transmission, but conventionally, optical communication devices for this type of audiovisual equipment have only been equipped with the light emitting part of the optical signal transmitter on the video player side. has one light emitting element, such as a light emitting diode, and a condensing lens that collects the light emitted from this light emitting element, and the light receiving section of the optical signal receiver on the TV receiver side receives the light. It has a structure including an element such as a photodiode and a convex lens that focuses the light transmitted from the optical signal transmitter onto the light receiving element.

This convex lens is a so-called parallel lens that converts an incident light beam into a parallel light beam and radiates it, and has a narrow range of incident angles.

However, with this conventional structure, it is difficult to achieve both ease of alignment of the optical axes when installing the transceiver and improvement of efficiency in optical signal transmission. In other words, in order to improve the efficiency of optical signal transmission, it is better to reduce the radiation angle of light from the optical signal transmitter. Axis alignment becomes like an axe. In addition, since optical signal receivers use convex lenses with a narrow range of incident angles to focus light onto the light-receiving element, the light focusing position does not shift (this increases restrictions on the installation of the transmitter and receiver). Optical axis alignment -1
1 was becoming even more difficult.

(Problem to be Solved by the Invention) As mentioned above, conventionally, 1' V
Since a wired method was used to transmit signals to the receiver, there were problems such as difficulty in changing the station location. Also,
Even in wireless systems, if radio waves are used to transmit signals, there is a risk of radio interference. Furthermore, even for devices that use light for signal transmission, conventional optical signal transmitters have only one light-emitting section and one light-emitting element combined with a condensing lens. There is a problem in that it is difficult to achieve both ease of axis alignment and improvement in efficiency in optical signal transmission, and
Since the optical signal receiver used a convex lens with a narrow range of incident angles, there were problems such as alignment of the optical axis becoming even more difficult.

The present invention aims to solve the above-mentioned problems, and uses light to transmit signals from the video player side to the TV receiver side in audio-visual equipment. In addition to being able to freely set up the vessels and making it easier to see [1]
The purpose is to prevent radio wave interference, improve the efficiency of optical signal transmission, and make it easier to align optical axes when installing transceivers. It is something.

[Structure of the invention]

(Means for Solving the Problems) In order to achieve the above-mentioned "I objective," the optical communication device in the audiovisual equipment of the present invention transmits electrical video and audio signals output from a video player using light, for example, infrared rays. an optical signal transmitter that converts the signal into a wireless signal and transmits it wirelessly;
an optical signal receiver that receives the light transmitted from the optical signal transmitter, converts it back into electrical video and audio signals, and outputs the light to the television receiver; , a main light emitting element, a condensing lens that condenses the light emitted from this main light emitting element, and a condensing lens that is arranged around the optical axis of these main light emitting elements and the condensing lens, and the light from this condensing lens. The optical signal receiver has a plurality of sub-light emitting elements that emit light in substantially the same direction and over a wider range, and the optical signal receiver serves as a light receiving section to emit light from the optical signal transmitter. The dome lens has a wide range of incident angles for refracting and condensing light toward the light receiving element.

(Function) In the optical communication device in the audiovisual equipment of the present invention, the optical signal transmitter converts electrical video and audio signals output from the video player into light and wirelessly transmits the light. At the same time, the optical signal receiver receives the light transmitted from the optical signal transmitter, converts it back into electrical video and audio signals, and outputs the signals to the television receiver. This television receiver then 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 focused by the condensing lens L/:7, and the light from this condensing lens is transmitted to the dome lens of the light receiving section of the optical signal receiver. The light is refracted toward the light-receiving element by the light-receiving element, and the light is received by the light-receiving element. By condensing the light with the condenser lens, the directivity of the transmission from the optical signal transmitter can be increased, and the efficiency of optical signal transmission can be improved. . In addition, since the lens of the light receiving part of the optical signal receiver is a dome lens with a wide range of incident angles, even if the angle of incidence of the light receiving part of the optical signal receiver with respect to the optical axis is large, the light from the optical signal transmitter Light is reliably focused on the light receiving element.

Also, when installing the transceiver, when aligning the optical axes of the light emitting part of the optical signal transmitter and the light receiving part of the optical signal receiver, for example, while looking at the television receiver, change the angular relationship of the transceiver. Explore. At this time, in the light emitting part of the optical signal transmitter, the main light emitting element and the plurality of sub light emitting elements arranged surrounding the optical axis of the condensing lens are emitted in substantially the same direction as the light from the condensing lens and over a wider range. First, rough alignment of the optical axis can be easily performed by emitting light.

Then, based on this, the adjustment can be made so that the light from the condenser lens is received by the light receiving element of the optical signal receiver.

(Embodiment) Hereinafter, the configuration of an embodiment of the optical communication device in audiovisual equipment of the present invention will be described based on the drawings.

In FIG. 1, 1 is a video player, which drives a record carrier such as a videotape or a video disc, reads signals recorded on the record carrier electromagnetically or optically, and electrically reads signals recorded on the record carrier. It converts into video and audio signals and outputs them.

Further, 2 is a television (TV) receiver including a speaker, and this TV receiver 2 reproduces video and audio from the electrical video and audio signals output from the video player 1. It is.

Furthermore, 3 is an optical signal transmitter, and this optical signal transmitter 3 is
The electrical video and audio signals output from the video player 1 are converted into infrared light, which is a type of light, and transmitted wirelessly. The optical signal transmitter 3 is detachably connected to the video player 1 via a cable 4 in order to input video and audio signals from the video player 1, and is also connected to a 100V AC power source. It has a power cord 5.

Further, 6 is an optical signal receiver, and this optical signal receiver 6 receives the light transmitted from the optical signal transmitter 3 and converts it back into electric video and audio signals and outputs them to the TV receiver 2. The TV receiver 2 is detachably connected to the TV receiver 2 by a cable 7.8.

Next, the configuration of the light emitting section 10 of the optical signal transmitter 3 is changed to a second one.
This will be explained based on the diagram.

The opening is a cylindrical holder made of synthetic resin, and at the rear end of this holder 11, one high-intensity infrared light emitting diode (LED) 13 mounted on a printed circuit board 12 is disposed as a main light emitting element. has been done. Furthermore, a condenser lens 14 made of a biconvex lens is attached to the front end of the holder 11 to condense infrared rays emitted forward from the infrared LED I3. The diameter of this condensing lens 14 is, for example, 30 ml11. Infrared rays are emitted forward from this condensing lens 14 within an angle range of about 5 to 10'. Furthermore, a printed circuit board 15 is attached to the front end of the outer peripheral side of the holder 11 with screws 16, and six infrared LEDs 7 as sub-light emitting elements are mounted on this printed circuit board 15 at equal intervals. These infrared rays L ED +7 are arranged on a circumference centered on the optical axis of the infrared ray L ED l:l and the lens 14, and each infrared ray L ED +7
It radiates forward in an angle range of about 20 degrees.

Note that the lens eye and the infrared LED+7 are covered from the front with a filter 18 made of synthetic resin.

Next, the configuration of the light receiving section 20 of the optical signal receiver 6 is changed to the third one.
This will be explained based on the diagram.

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 screws 23, and a dome lens 24 for condensing light is held in this lens holder 22. Further, a printed circuit board 25 is disposed inside the case 21, and a pin photodiode 26 as a light receiving element is mounted on this printed circuit board 25.
is installed. This pin photodiode 2G is
It is located behind the dome lens 24 and on its optical axis. The dome lens 24, which is a semi-spherical lens, refracts the infrared rays transmitted from the optical signal transmitter 3 toward the pin photodiode 26, but the range of the incident angle is very large. It's getting wider. In addition,
The dome lens 24 is covered from the front with a filter 27 made of synthetic resin.

Next, the fourth section regarding the electrical configuration of the optical signal transmitter 3 will be explained.
This will be explained with reference to the block diagram shown in the figure.

In the figure, 31 is an NTSC video signal input terminal, and this input terminal 31 is used to input a video signal from the video player 1, that is, a video signal including a synchronization signal. Further, 32 is a low-pass filter, 33 is a clamp circuit, 34 is a pre-emphasis circuit, and 35 is a Daviny filter.
36 is a white clip circuit, 37 is a modulation circuit, 38 is a synchronizing signal separation circuit, 39 is a carrier adjustment circuit, and 40 is a J, ED drive circuit.

Here, the low-pass filter 32 transmits the frequency range (0 to 5 former 1y) necessary for the video signal to the next block, and cuts frequencies above 5M1lz, thereby reducing noise etc. It is something that makes you The clamp circuit 33 keeps the DC component of the video signal at a constant voltage. The pre-en 7797 circuit 34 is for emphasizing the high frequency components of the video signal, and is for improving the S/N ratio by performing de-emphasis later on the receiving side. The divinization adjustment circuit 35 adjusts frequency deviation for frequency modulation. White clip circuit 3
6 is for adjusting the video white level.

The modulation circuit 37 frequency modulates (FM) the video signal. The synchronization signal separation circuit 38 separates the horizontal synchronization signal from the video signal. The carrier adjustment circuit 39 adjusts the fundamental frequency for frequency modulation.

The LED drive circuit 40 amplifies the modulated signal and drives the infrared LED I 3.17.

Also, 41 is the order of the first channel (CIl, I),
This audio input terminal 41 is for inputting the CIl, l 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, 4G is a limiter, 147 is a modulation circuit, 48
49 is a divinion adjustment circuit, and 50 is a key rear adjustment circuit. Further, 51 is an LED drive circuit, and this LED
The drive circuit 51 includes the infrared ray I.

It drives EDI3.17.

Here, the auto gain control circuit 43 automatically adjusts the gain. Further, the noise reduction conbrella blade 44 is for reducing noise.

Furthermore, 52 is an audio input terminal of the second channel Y (L2), and this audio input terminal 52 is used to manually input the audio signal of C11,2 from the video player 1. Note that the audio input terminal 5 of this CIl,2
2 and the infrared LED+3.17 is connected to the audio input terminal 41 of the C111 and the infrared LED
It is almost the same as the circuit provided between DI3.17. Therefore, details are not shown.

Note that the infrared LEDs 13.17 are connected to a DC power source (Vc
c) as a power source and emits infrared rays with a wavelength of 890 nn+.

Next, a fifth section regarding the electrical configuration of the optical signal receiver 6 will be explained.
This will be explained with reference to the block diagram shown in the figure.

A resistor 60 and the pin photodiode 26 are connected in series between the two poles of the DC power supply, and a preamplifier 6 is connected between the resistor 60 and the pin photodiode 26.
1 is connected. Further, 62 is a limiter, 163 is a demodulation circuit, 64 is a low-pass filter, 65 is a de-emphasis circuit, 66 is a bypass 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 includes a first pin photodiode 26.
This amplifies the electrically modulated signal generated by light reception. The limiter 62 adjusts the level of the amplified signal to an appropriate value. The demodulation circuit 63 demodulates the frequency modulated signal and returns it to the original signal. The low-pass filter 64 cuts high frequency components of the demodulated signal.

The de-emphasis circuit 65 restores the emphasis to the video signal, which has been emphasized by the pre-emphasis circuit 34 on the transmitting side.

The bypass filter 66 cuts extra low frequency components of the video signal. The video amplifier 67 amplifies the video signal and adjusts it to a level that can be connected to the TV receiver 2.

Also, 71 is a band pass filter, and 72 is a limiter.
173 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. Furthermore, 79 is an audio output terminal of C11,1, and this audio output terminal 79 outputs the audio signal of CI+,1 to the TV receiver 2.

Here, the noise reduction expander 76 is for reducing noise.

The audio amplifier 78 amplifies the audio signal and adjusts it to a level that can be connected to the TV receiver 2.

Furthermore, 80 is an audio output terminal of CI+,2, and this audio output terminal 80 is connected to the TV receiver 2 by CI(,
This outputs the second audio signal. Note that the circuit provided between the preamplifier 61 and the audio output terminal 80 of CI+,2 is the circuit provided between the preamplifier 61 and the audio output terminal 80 of CI+,2.
This circuit is the same as the circuit provided between the audio output terminal 79 and the audio output terminal 79. Therefore, details are not shown.

An example of the specifications of the transceiver 3.6 is as follows. That is, the possible distance between the transmitter and receiver 3.6 is 0
~10m1 Possible reception angle varies depending on the distance, but 5
~10°. Note that the angle between the transmitter and receiver 3 and 6 can be adjusted when installed. Also, the reception sensitivity is 5NI1
That's all. Furthermore, input/output terminal 31.41.52.6
8.79.80 can be, for example, a switching system between a bin jack and a BCN connector. Also, the approximate dimensions of the transceiver 3.6 are 150nm x 120mm
It is approximately X60+nm.

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

First, the optical signal transmitter 3 converts 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 electrical signals are converted into infrared light by the infrared light LED 13.
The infrared rays are focused by the condensing lens 14 and radiated. In addition, other infrared LED 1? The same signal is sent from

Further, the optical signal receiver 6 receives the infrared rays transmitted from the optical signal transmitter 3, converts the signals back into electrical video and audio signals, and outputs them to the TV receiver 2. That is, the infrared rays from the condensing lens 14 of the optical signal transmitter 3 are transmitted to the dome lens 2.
4, the light is refracted and focused toward the pin photodiode 26, received by the pin photodiode 26, and converted into an electric signal.Furthermore, demodulation etc. are performed by the configuration shown in FIG. Electrical video and audio signals are output to the TV receiver 2.

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

According to the above configuration, since there is no need for a cable for signal transmission from the video player 1 to the TV receiver 2, AV equipment can be freely installed without being restricted by this cable, which is convenient.

Therefore, it is possible to easily change the installation location of the Δ■ equipment without spending much money. Along with this, ``1'' will also get better.

Furthermore, since infrared light, which is a type of light, is used for signal transmission, there is no risk of violating the regulations of the Radio Law, and there is no possibility of causing interference with radio waves. In other words, various devices related to radio waves will not be interfered with.

As a signal transmission medium, infrared rays are also excellent in that they have short wavelengths and have strong straightness (and strong directivity).

Furthermore, in signal transmission, by condensing light with the condenser lens 14, the directivity of transmission from the optical signal transmitter 3 can be increased, and for example, an S/N ratio of 5Nl1 or more can be obtained.
In this way, it is possible to improve the efficiency of optical signal transmission.

Note that transmission and reception between the transceiver 36 can also be performed by the infrared rays LEI)+7 located around the light emitting unit 10 of the optical signal transmitter 3, but the S/N ratio obtained by the infrared rays 17ED17 at the periphery is 40~40. It is 5NIl or less.

Furthermore, in the optical signal receiver 6, since the lens for condensing light onto the pin photodiode 26 is the dome 1 nons 24 with a wide range of incident angles, the light receiving section 20 of the optical signal receiver 6
Even if the angle of incidence with respect to the optical axis is large, the infrared rays from the optical signal transmitter 3 are reliably focused on the pin photodiode 26. That is, even if the optical axis of the light emitting section 10 of the optical signal transmitter 3 is angularly shifted from the optical axis of the light receiving section 20 of the optical signal receiver 6, the light focusing position by the dome lens 24 is almost at the pin photodiode. The pin photodiode 26 is kept at a constant position, and light reception by the pin photodiode 26 is reliably performed.

As a result, the permissible range of the one-ball position of the transceivers 3 and 6 becomes large, and the installation of the transceivers 3 and 6 becomes easy.

By the way, when setting up the transceivers 3 and 6, when aligning the optical axes of the light emitting section 10 of the optical signal transmitter 3 and the light receiving section 20 of the optical signal receiver 6, while looking at the TV receiver 2, Search is performed by changing the angular relationship of 3 and 6. That is, the angular relationship between the transceivers 3 and 6 is adjusted so that the image on the TV receiver 2 is as clear as possible and its colors are sufficiently displayed.

At this time, the light emitting unit 10 of the optical signal transmitter 3 emits infrared light L E
A plurality of infrared LEDs 17 arranged surrounding the optical axis of the D 13 and the condensing lens 14 emit infrared rays in substantially the same direction as the infrared rays from the condensing lens 14 and over a wider range, first of all. Optical axis alignment can be easily performed. Then, based on this, adjustment can be made so that the infrared rays from the condenser lens 14 are received by the pin photodiode 26 of the optical signal receiver 6J. That is, in adjusting the angular relationship between the transceivers 3 and 6, the condenser lens The infrared rays from 14 are transmitted to the pin photodiode 2G of the optical signal receiver 6.
As a result, the light is received by the camera, and a clear image can be obtained.

Thus, according to the above configuration, in the light emitting unit 10 of the optical signal transmitter 3, in addition to the infrared LED+3 combined with the condenser 1 non-zero 14, a plurality of infrared LEDs 17 with a larger radiation range are provided. This makes it possible to improve the efficiency in transmitting infrared signals, and also because the lens for condensing light onto the binfist diode 26 in the optical signal receiver 6 is a dome lens 21 with a wide range of incident angles. This makes it possible to easily align the optical axes when installing the transceiver 3.6.

Moreover, since condensing lenses are not intertwined with the plurality of infrared LEDs 7 that are sub-light emitting elements, the cost can be reduced.

〔Effect of the invention〕

According to the present invention, there is provided an optical signal transmitter that converts electrical video and audio signals output from a video player into light and transmits it wirelessly, and a light signal transmitter that receives the light transmitted from the optical signal transmitter and retransmits it. Since it is equipped with an optical signal receiver that converts electrical video and audio signals and outputs them to a television receiver, audio-visual equipment can be installed freely and looks good. In addition, since light is used for signal transmission, there will be no interference with radio waves. The light emitting section of the optical signal transmitter includes a main light emitting element, a condenser lens that condenses light from the main light emitting element, and a condenser lens that surrounds the optical axis of the main light emitting element and the condenser lens. It has multiple sub-light emitting elements that emit light in approximately the same direction as the light of It is possible to achieve both of the following: Furthermore, the receiver of the optical signal receiver has a dome lens with a wide range of incident angles that refracts and focuses the light from the optical signal transmitter toward the light receiving element.
The permissible range of positions for installing the transceiver becomes larger, the installation of the transceiver becomes easier, and optical axis alignment becomes even easier.

[Brief explanation of the drawing]

The drawings show an embodiment of the optical communication device in the audiovisual equipment of the present invention, in which FIG. 1 is an overall perspective view, FIG. 2(a) is a side view of the light emitting part of the optical signal transmitter, and FIG.
Figure (b) is a front view of the same light emitting part, Figure 3 is a side view of the light receiving part of the optical signal receiver, Figure 4 is a block diagram showing the electrical configuration of the optical signal transmitter, and Figure 5 is the optical signal FIG. 2 is a block diagram showing the electrical configuration of a receiver. ■...Video player 2...Television receiver,
3. Optical signal transmitter, 6. Optical signal receiver, 10. Light emitting unit, 13. Infrared light emitting diode as main light emitting element, 14. Condensing lens, 17. Infrared light as sub light emitting element. Light emitting diode, 20...light receiving section, 24...dome lens, 26...bin photodiode as a light receiving element. Invented on July 19, 1990 by Hiroaki Tanaka

Claims (1)

[Claims] (1) An optical signal transmitter that converts the electrical video and audio signals output from the video player into light and transmits it wirelessly; and an optical signal receiver that returns the video and audio signals and outputs them to the television receiver; the optical signal transmitter includes a main light emitting element as a light emitting section, and collects light emitted from the main light emitting element. A condenser lens, and a plurality of sub-light emitting elements that are arranged around the optical axis of the main light emitting element and the condenser lens and emit light in substantially the same direction as the light from the condenser lens and over a wider range. The optical signal receiver includes, as a light receiving section, a light receiving element and a dome lens having a wide range of incident angles that refracts and focuses the light transmitted from the optical signal transmitter toward the light receiving element. An optical communication device in audiovisual equipment, characterized in that: