JPH05336044A - Optical space transmitter - Google Patents

Abstract

PURPOSE:To correct the radiation position of an optical beam in tracking with fluctuation in a relative position between a sender side and a receiver side. CONSTITUTION:A light detected and outputted from a light emitting diode 33 of a reception unit 3 is received by a position deviation detector 16 of a transmission unit 1 and a deviation between a radiation position of a laser beam outputted from a laser diode 13 of the transmission unit 1 and a position of a light receiving element 31 of the reception unit 3 is detected based on the light receiving position. An actuator driver 15 turns an actuator 14 supporting the laser diode 13 in vertical and horizontal directions based on the deviation in vertical and horizontal directions. Thus, the radiation position of an optical beam is corrected in response to it when not only the sender side but also the receiver side is moved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for transmitting information such as video and audio in an optical space.

[0002]

2. Description of the Related Art Conventionally, as a method of transmitting information such as video and audio in an optical space, for example, Japanese Patent Laid-Open No. 1-236871.
Japanese Patent Application Laid-Open No. 3-2148881 and Japanese Patent Application Laid-Open No. 3-21488
Each publication such as No. 882 discloses a method of FM-modulating and transmitting light output from an infrared LED.

However, since the light output from the infrared LED is diffused light, it is possible to cover a wide range of positional deviation between the transmitting side and the receiving side, but the amount of light is attenuated by diffusion, so the transmission distance is limited. However, when using a plurality of devices, there is a problem that signals of the devices interfere with each other. Further, when used indoors, light is diffusely reflected on the ceiling, walls, floor, etc., and noise occurs in the case of a high frequency signal, so there is a problem that the upper limit of the modulation frequency cannot be set high.

Therefore, if the laser light is modulated by a predetermined information signal and spatially transmitted, the laser light can be prevented from being diffused by forming the laser light into a parallel beam by a collimating lens or the like, and the above-mentioned problems can be solved. be able to. However, on the other hand, since the laser beam is made into a parallel beam, it hinders the transmission of information when the relative position between the transmitting side and the receiving side is deviated, so the irradiation direction of the laser beam is changed according to the positional deviation. It becomes necessary to correct.

In response to this, Japanese Patent Laid-Open No. 62-27483
Japanese Patent Laid-Open No. 7-235438 proposes a method for correcting and controlling the sending direction of laser light for information transmission using a half mirror and an image pickup device, and Japanese Laid-Open Patent Publication No. 3-235438 discloses a focal plane of a lens on the transmitting side or the receiving side. A method has been proposed in which the orientation of the device is detected by a mirror arranged above, and further, Japanese Patent Laid-Open No. 3-236.
Japanese Patent Laid-Open No. 640 proposes a method in which an inclinometer or an accelerometer detects vertical and horizontal variations of the laser beam and corrects the irradiation position of the laser beam based on the result.

[0006]

However, in the method disclosed in Japanese Unexamined Patent Publication No. 62-274837, a part of the laser light for information transmission is used for detecting the sending direction of the laser light, so that the reception is performed. However, there is a problem that the output of the signal sent to the side is reduced, and that it takes a long time for image processing and the like, so that the response of the correction in the sending direction is delayed. Further, if the laser light is not applied to the half mirror at the time of initial setting, the sending direction of the laser light cannot be detected, and indirect correction is performed to align the receiving side device and the laser light on the half mirror. There was a problem that became.

On the other hand, the method disclosed in Japanese Unexamined Patent Publication No. 3-235438 is a complete manual correction, and it is impossible to correct the optical axis by following the change in the relative position between the transmitting side and the receiving side during communication. Therefore, there is a problem that the optical axis correction becomes uncertain when used in a place where vibration easily occurs. Further, the method disclosed in Japanese Patent Laid-Open No. 3-236640 has a problem in that it can follow position fluctuations on the transmitting side, but cannot follow position fluctuations on the receiving side. Further, in the conventional optical space transmission method using the above laser light, there is a problem in personal safety because the laser light is emitted into the space.

The present invention has been made in view of the above problems, and enables the long-distance signal transmission by high frequency, and the relative positions of the transmitting side and the receiving side change due to the movement of the receiving side as well as the transmitting side. Even so, it is an object to provide an optical space transmission device capable of correcting the irradiation position of the light beam in response to the fluctuation.

[0009]

In order to solve the above problems, the present invention provides a transmitting unit for outputting a light beam modulated on the basis of a predetermined information signal, and a receiving unit for receiving and demodulating the light beam. In an optical space transmission device comprising: a laser beam is used as the light beam, the receiving unit is provided with a light source that outputs detection light for detecting an irradiation position deviation of the light beam toward the transmitting unit,
The transmission unit, a light-receiving element having a light-receiving section in a predetermined area irradiated with the detection light, a detection section for detecting the irradiation position of the detection light in the light-receiving section, and the light based on the detection result of the detection section. A correction means for correcting the irradiation direction of the beam is provided.

[0010]

According to the optical space transmission device of the present invention, the irradiation direction of the light beam for information transmission is corrected according to the variation of the irradiation position of the detection light output from the reception unit side on the transmission unit side. The irradiation position of the light beam can be corrected in response to a change in the position of the receiving unit as well as the transmitting side.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. 1 is a block diagram showing a schematic configuration of an optical free space transmission apparatus according to an embodiment of the present invention, FIG. 2 is an exploded perspective view showing a specific configuration of a transmission unit shown in FIG. 1, and FIG. FIG. 3 is an exploded perspective view showing a physical structure.

As shown in FIG. 1, the optical space transmission apparatus of this embodiment includes a transmission unit 1 and a reception unit 3. The transmission unit 1 includes, for example, a video signal input from a video output terminal of a video playback device (not shown) via the jack 51 and a signal cable 5, and a voice output terminal of the video playback device (not shown) to a jack. An FM modulation circuit 11 that modulates the L and R audio signals that are input via the signal cables 5 and 52 and 53, and a laser driver 12 that drives the laser diode 13 to emit light based on this modulation signal. ..

The laser diode 13 outputs a laser beam (corresponding to a light beam, hereinafter abbreviated as a laser beam) in the visible light region for information transmission, and is held by an actuator 14 which can be swung vertically and horizontally. Has been done. The actuator 14 is driven by an actuator driver 15, and by driving the actuator 14, the irradiation direction of the laser light output from the laser diode 13 is displaced in the vertical and horizontal directions.

Reference numeral 16 in FIG. 1 is a position shift detector,
The irradiation position of the laser light from the laser diode 13 and the light receiving element 31 on the receiving unit 3 side that receives the laser light.
The amount of positional deviation with Then, the actuator driver 15 determines the vertical and horizontal turning amounts of the actuator 14 based on the positional shift amount detected by the positional shift detector 16.

Reference numeral 17 in FIG. 1 denotes a laser safety circuit, which is provided with a light receiving element 28 (see FIG. 2) for detecting an obstacle, and a light emitting diode 33 (corresponding to a light source) of a receiving unit 3 described later.
When the amount of the detection light output from the light receiving element 28 received by the light receiving element 28 decreases or becomes zero, or when the light receiving unit 40 (see FIG. 2) of the position shift detector 16 (see below) a two-divided sensor 91 (light receiving portion). Light emitting diode 3
The actuator driver 15 is controlled so that the output of the laser light from the laser diode 13 is stopped when the received light amount of the detection light from the laser light 3 becomes zero.

On the other hand, the receiving unit 3 demodulates the light receiving element 31 for receiving the laser light from the laser diode 13 and the laser light received by the light receiving element 31 and outputs the video signal of the demodulated signal to the signal cable 7. For example, the audio signals of L and R, which are output to the video input terminal of a television (not shown) via the jack 71, and the demodulated signals are output via the signal cable 7 and the jacks 72 and 73. A demodulation circuit 32 for outputting to the audio input terminal of the television shown in the figure and a light emitting diode 33 for outputting detection light for detecting the positional deviation by the positional deviation detector 16 are provided.

Next, the concrete structure of the transmission unit 1 is shown in FIG.
Will be described. The transmission unit 1 includes a housing 20 including a base 21 and a cover 22, and a standing piece 21 a of the base 21 located on the front surface of the housing 20.
Is provided with a filter 35 that cuts off light having a wavelength other than infrared light, for example, light such as sunlight and indoor lighting, and is also provided with a plurality of light receiving elements 28 for detecting an obstacle described later. The respective light receiving elements 28 are arranged at equal intervals around the filter 35, and the mutual intervals are, for example, equal to or slightly shorter than the size of the hand of a child (50 mm or less).

On the other hand, the optical head 30 and the substrate 37 are housed inside the housing 20. The board 37 has F
The M modulation circuit 11, the laser driver 12, the actuator driver 15, the detection circuit (not shown) of the position shift detector 16, the laser security circuit 17, and the jacks 54, 55, 56 of the signal cable 5 are connected to the FM modulation circuit 11. A connector (not shown) is mounted on the optical head 30, and the optical head 30 includes a laser diode 13 and an actuator 14.
And are installed.

FIG. 4 is a partially cutaway enlarged perspective view showing a schematic structure of the optical head 30. As shown in FIG. 4, the laser diode 13 collimates the laser light in the visible light region outputted from the laser diode 13. It is held by a cylindrical holder 38 together with the collimator lens 18 that shapes the light flux into various light fluxes. On both sides of this holder 38 (only the left side is shown in FIG. 4), the light receiving unit 4 of the position shift detector 16 is provided.
The holding piece 38a for holding 0 extends and the holder 38a
And the holding piece 38a includes the support shaft 38b and the bearing 42a.
It is rotatably supported in the left-right direction by the sub-frame 42 via.

The holder 3 is provided on the inner peripheral surface of the sub-frame 42.
8 is attached to a permanent magnet 45a of a voice coil motor 45 that rotates 8 in the left-right direction with respect to the subframe 42. The permanent magnet 45a has a coil of the voice coil motor 45 attached to the rear end of the holder 38. 45b is facing. The sub-frame 42 is supported by the main frame 58 via a support shaft 42b and a bearing 58a so as to be vertically rotatable.

A permanent magnet 48a of a voice coil motor 48 for rotating the sub-frame 42 in the vertical direction with respect to the main frame 58 is attached to the inner peripheral surface of the main frame 58. The coil 48b of the voice coil motor 48 attached to the rear end of the sub-frame 42 is exposed.

The voice coil motors 45 and 48
Is a coil 45b by the actuator driver 15,
With the energization of 48b, its permanent magnets 45a, 48a
The electromagnetic force generated in relation to the magnetic field causes the holder 38 to which the coils 45b and 48b are attached and the sub-frame 42 to rotate in the horizontal and vertical directions. In this embodiment, the holder 38, the sub-frame 42, the voice coil motors 45 and 48, and the main frame 58 constitute the actuator 14, and the actuator 14 and the actuator driver 15 constitute the correction means.

Further, the light receiving unit 40 of the position shift detector 16 held by the holding piece 38a is shown in FIGS. 5 (a) and 5 (b).
As shown in FIG. 5, the mountain-shaped light shielding member 81 is configured by a two-divided sensor 91 having two sensor portions 91a and 91b on both slopes. The two-divided sensor 91 of the light receiving unit 40 located on the left side of the holder 38 shown in FIG.
Uses a sensor which is divided into two parts vertically for detecting a positional deviation in the vertical direction. On the contrary, a two-part sensor which does not appear in FIG. A sensor that is divided into two parts on the left and right is used to detect the deviation. Then, depending on the inclination of the light incident on the two-divided sensor 91 via the filter 35, a difference occurs between the output signals from the upper and lower or left and right sensor portions.

Next, the concrete structure of the receiving unit 3 is shown in FIG.
Will be described. The receiving unit 3 includes a housing 24 including a base 25 and a cover 26, and the standing piece 25 a of the base 25 located on the front surface portion of the housing 24.
Is provided with a filter 34 similar to the filter 35 of the transmission unit 1.

On the other hand, the substrate 6 is provided inside the housing 24.
1, 62 are accommodated. The light receiving element 31 and the light emitting diode 33 described above are mounted on the board 61, and the board 62 is provided for connecting the demodulation circuit 32 and the jacks 74, 75, 76 of the signal cable 7 to the demodulation circuit 32. A connector (not shown) is mounted. Light receiving element 31
Are arranged substantially in the center of the substrate 61, and the light emitting diodes 33 are arranged on both sides of the light receiving element 31.

In this embodiment, it is assumed that a large amount of relative positional deviation between the transmitting unit 1 and the receiving unit 3 occurs in the vertical direction, and the detection light emitted from the light emitting diode 33 and the light receiving unit 40 are separated from each other. In order to widen the amount of offset in the vertical direction, the light emitting diode 33 is connected to the light receiving element 3.
Two are arranged on each side, one on each side. And
The distance between the light receiving element 31 and the upper and lower two light emitting diodes 33 arranged on both sides of the light receiving element 31 is set to correspond to the distance between the laser diode 13 and the light receiving unit 40 in the transmitting unit 1.

Next, the operation of the optical free space transmission apparatus of this embodiment will be described. First, the transmission unit 1 and the reception unit 3 are arranged such that the standing pieces 21a and 25a of the transmission unit 1 and the reception unit 3 face each other in the vertical and horizontal directions. In this state, the video signal and the L and R audio signals are transmitted from the video reproducing device (not shown) through the signal cable 5 and the jacks 51 to 56 to the F signal.
When input to the M modulation circuit 11, the video and audio signals are FM-modulated and input to the laser driver 12. Then, the laser light output from the laser diode 13 is modulated by the laser driver 12 based on this modulation signal, and is output toward the light receiving element 31 of the receiving unit 3.

At this time, the light emitting diode 33 of the receiving unit 3 outputs the detection light toward the transmitting unit 1 at a predetermined spread angle, and the detection light is the laser light output from the laser diode 13. Of the light receiving unit 40 of the transmitting unit 1 (passing through the peripheral portion in the radial direction of the
The split sensor 91) is also illuminated, and the light receiving element 28 for obstacle detection is also illuminated.

Therefore, during the output of the laser light from the laser diode 13, the relative positions of the transmitting unit 1 and the receiving unit 3 are displaced, and the direction of the laser light from the laser diode 13 is changed to the light receiving element 31. When it is deviated from the center of, the direction of the deviation is detected by subtracting the output signal of the two-divided sensor 91 by a detection circuit (not shown) of the positional deviation detector 16. Then, the actuator 14 is driven by the control of the actuator driver 15 based on the detection result, and the orientation of the holder 38 holding the laser diode 13 is corrected toward the center of the light receiving element 31.

At least one of the two-divided sensor 91
When the received light amount of the detection light from the light emitting diode 33 becomes zero, the fact is detected by the position shift detector 16 and the laser safety circuit 17, and accordingly, the laser diode 13 is controlled by the laser driver 12 by the control. The output of the laser light is stopped.

On the other hand, a plurality of light receiving elements 28 for detecting obstacles
When the detection light from the light emitting diode 33 is emitted to the laser, the amount of the detection light received by each light receiving element 28 is changed to the laser safety circuit 1.
If the amount of received light falls below a predetermined threshold value or becomes zero, the laser driver 12
The output of the laser light from the laser diode 13 is stopped by the control of.

That is, when the direction of the laser beam from the laser diode 13 with respect to the light receiving element 31 is deviated,
The deviation is corrected by driving the actuator 14. Further, when a relative positional deviation occurs between the transmitting unit 1 and the receiving unit 3 so that the light receiving element 31 is not irradiated with the laser light, or from the light emitting diode 33 passing through the peripheral portion in the radial direction of the laser light. When there is a possibility that the detection light will be blocked by some obstacle (for example, the hand of an infant) and the obstacle will be irradiated with the laser light from the laser diode 13, the laser safety circuit 17 and the laser driver 12 The output of the laser light from the laser diode 13 is stopped by the control.

As described above, in the optical transmission device of this embodiment,
In addition to the laser light in the visible light region for information transmission, the detection light for detecting the positional deviation is output from the light emitting diode 33 of the reception unit 3 toward the transmission unit 1, and the fluctuation of the detection light is transmitted to the transmission unit 1 side. Since the relative displacement between the transmission unit 1 and the reception unit 3 is detected by monitoring with, and the irradiation direction of the laser light is corrected corresponding to this, not only the transmission unit 1 but also the reception unit Unit 3
Even if the position changes, the irradiation direction of the laser light can be corrected by following the position change.

Further, when the detection light is no longer applied to the two-divided sensor 91, or when the detection light from the light emitting diode 33 which is received by the plurality of light receiving elements 28 after passing through the peripheral portion in the radial direction of the laser light is blocked. At this time, the output of the laser light from the laser diode 13 is stopped by the control of the laser driver 12 when it is turned on, so that it is possible to prevent a person or the like from being inadvertently irradiated with the laser light. Further, since the laser light in the visible light region is shaped into a parallel light flux by the collimator lens 18 and used for information transmission, the diffusion of light is reduced as compared with the light emitted by the infrared LED, and therefore, the high-frequency long-distance information transmission is performed. Can be possible.

In this embodiment, when the transmitting unit 1 and the receiving unit 3 are misaligned so that the light receiving element 31 is not irradiated with the laser light, or when the laser light passes through the peripheral portion in the radial direction of the laser light. When the detection light from the light emitting diode 33 received by the plurality of light receiving elements 28 is blocked by the laser driver 12, the laser diode 13 is controlled by the laser driver 12.
Although the output of the laser light from the laser is stopped, an electric or mechanical shutter is arranged on the optical path of the laser light in the transmission unit 1 so that the shutter is closed in the above-mentioned state. Good.

For example, the transmission unit 1 and the reception unit 3
If the liquid crystal shutter disposed on the optical path of the laser light is closed when the position is shifted so that the light receiving element 31 is not irradiated with the laser light, the configuration shown in FIG. 6 may be used.

First, the differential amplifiers 78 and 79 differentiate the two outputs, that is, the upper and lower sides or the left and right sides, from the two two-divided sensors 91 for detecting the upper and lower sides and the left and right sides which are irradiated with the detection light.
When the upper and lower difference signals thus obtained are within a certain level near zero, the binarizing circuits 66 and 67 output "H", and in other cases, "L" is output. The AND circuit 68 takes the logical product of the outputs of the binarization circuits 66 and 67. When the AND circuit 68 outputs "H", the liquid crystal shutter 64 opens, and when it outputs "L". The liquid crystal driver 65 may control so that the liquid crystal shutter 64 is closed.

In this embodiment, the light receiving unit 40 is
Two sensor portions 91 are provided on both side slopes of the mountain-shaped light shielding member 81.
Although the two-division sensor 91 having a and 91b is used, for example, the two-division sensor 92 in which two sensor portions 92a and 92b are arranged on both sides of a plate-like light shielding member 82 as shown in FIG. 7A is used. Alternatively, a 4-division sensor 93 as shown in FIGS. 8A and 8B may be used. That is, the four-divided sensor 93 is composed of four sensor portions attached to the rear end of the cylinder 95 with a pinhole 95a formed in the front end and a light-shielding line cut inside. Like this 4
According to the light receiving unit 40 using the split sensor 93,
With only one light receiving unit 40, the output signals from the upper, lower, left, and right four sensor portions differ according to the inclination of the light incident on the four-division sensor 93, and the light is shielded by the cylinder 95. The difference is easy to come out.

Further, in this embodiment, the support shaft 38b of the holder 38 and the support shaft 42b of the sub-frame 42 are supported by bearings 42a and 58a, respectively, but they may be supported by leaf springs or the like. May be. Furthermore, the rotation of the holder 38 and the sub-frame 42 is
Other than the voice coil motors 45 and 48, other small motors such as ultrasonic motors may be used, or a material such as a piezoelectric element or a bimorph that is deformed by a voltage may be used without using a motor. ..

[0040]

As described above, according to the present invention, an optical space provided with a transmitting unit for outputting a light beam modulated based on a predetermined information signal and a receiving unit for receiving and demodulating the light beam. In the transmission device, a laser beam is used as the light beam, the receiving unit is provided with a light source that outputs detection light for detecting an irradiation position deviation of the light beam toward the transmitting unit, and the transmitting unit,
A light receiving element having a light receiving portion in a predetermined area irradiated with the detection light, a detection portion for detecting an irradiation position of the detection light in the light receiving portion, and an irradiation direction of the light beam based on a detection result of the detection portion. The correction means for correcting is provided. Therefore, the irradiation direction of the light beam for information transmission is corrected according to the variation of the irradiation position of the detection light output from the receiving unit side on the transmitting unit side, and the position of not only the transmitting unit but also the receiving unit fluctuates. Even when it occurs, the irradiation position of the light beam can be corrected accordingly. Further, since the laser light is used for information transmission, the infrared LED
Light diffusion is reduced as compared with the light emitted by, and therefore, long-distance information transmission by high frequency can be enabled. Further, according to the present invention, it is possible to improve the personal safety even when the laser light is emitted into the space.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of an optical free space transmission apparatus according to an embodiment of the present invention.

FIG. 2 is an exploded perspective view showing a specific configuration of the transmission unit shown in FIG.

FIG. 3 is an exploded perspective view showing a specific configuration of the receiving unit shown in FIG.

4 is a partially cutaway enlarged perspective view showing a specific configuration of the optical head shown in FIG.

5 is a diagram showing a schematic configuration of a two-divided sensor used in a light receiving unit of the positional deviation detector shown in FIG.
5A is a front view, and FIG. 5B is a side view.

FIG. 6 is an explanatory diagram showing, in a partial block diagram, another embodiment of a configuration in which output of laser light is stopped in response to a shift in the irradiation direction of laser light.

FIG. 7 is a diagram showing a schematic configuration of another two-divided sensor used in the light receiving unit of the displacement detector, FIG.
Is a front view, and FIG. 7B is a side view.

FIG. 8: 4 used in light receiving unit of position shift detector
It is a figure which shows schematic structure of a division sensor, FIG.8 (a) is a front view, FIG.8 (b) is a side view.

[Explanation of symbols]

 1 Transmitting Unit 3 Receiving Unit 11 FM Modulating Circuit 12 Laser Driver 13 Laser Diode 14 Actuator (Correction Means) 15 Actuator Driver (Correction Means) 16 Position Deviation Detector 17 Laser Security Circuit 18 Collimating Lens 20, 24 Housing 21, 25 Base 21a , 25a Standing piece 22, 26 Cover 28 Light receiving element 30 Optical head 31 Light receiving element 32 Demodulation circuit 33 Light emitting diode (light source) 34, 35 Filter 37, 61, 62 Substrate 38 Holder 38a Holding piece 38b Spindle 40 Light receiving unit 42 Sub Frame 42a Bearing 42b Spindle 45,48 Voice coil motor 45a, 48a Permanent magnet 45b, 48b Coil 51-56 Jack 58 Main frame 58a Bearing 64 Liquid crystal shutter 6 5 Liquid crystal driver 66,67 Binarization circuit 68 AND circuit 71-76 Jack 78,79 Differential amplifier 81,82 Light-shielding member 91,92 2 division sensor (light receiving part) 91a, 91b, 92a, 92b Sensor part 93 4 division Sensor (light receiving part) 95 Cylindrical 95a Pinhole

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical indication location H04B 10/00 H04N 7/22 8943-5C 8426-5K H04B 9/00 C (72) Inventor Ishizuka Yoshi 2-14-9 Tamagawadai, Setagaya-ku, Tokyo Kyocera Corporation Tokyo Yoga Works

Claims (2)

[Claims] 1. An optical space transmission device comprising: a transmission unit that outputs a light beam modulated based on a predetermined information signal; and a reception unit that receives and demodulates the light beam. A laser light in an optical region is used, the receiving unit is provided with a light source that outputs detection light for detecting the irradiation position deviation of the light beam toward the transmission unit, and the transmission unit is irradiated with the detection light. A light-receiving element having a light-receiving portion in a predetermined region, a detection portion that detects the irradiation position of the detection light in the light-receiving portion, and a correction unit that corrects the irradiation direction of the light beam based on the detection result of the detection portion, An optical space transmission device comprising: 2. The transmitting unit, when the irradiation direction of the light beam to the receiving unit is deviated, or when there is a possibility that the light beam is irradiated on an obstacle,
The optical space transmission device according to claim 1, further comprising means for stopping the output of the light beam.