JPH04297141A - Spacial light transmitting device - Google Patents

Abstract

PURPOSE:To easily detect the location of a radiation flux and to easily radiate the radiation flux to a reception part. CONSTITUTION:An adjustment mechanism 11 adjusting the space between a light emitting element 1 of a transmission part and a projection lens 3 is provided. Thus, the radiation light flux diameter in the reception part can be adjusted and the radiation light flux can be increased up to secure the necessary light receiving amount. Thus, the radiation positioning accuracy can be remarkably alleviated. By providing the sight optical system on the transmission part, the radiation position can be confirmed and adjusted with high accuracy.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spatial optical transmission device capable of converting an audio signal or a video signal into an optical signal, transmitting the signal wirelessly through space, and receiving the signal at a remote location.

0002

BACKGROUND OF THE INVENTION When audio/visual output devices such as TV receivers, video projectors, and speakers are placed at a location away from a signal source, it is necessary to route cables as signal lines, which is very inconvenient. Ta. For this purpose, spatial light that converts electrical signals such as audio and video from a signal source into optical signals, propagates them wirelessly in space, reproduces them into electrical signals using a light receiving device placed at a remote location, and connects them to speakers, etc. Transmission devices are considered to be promising in the future.

FIG. 6 shows an example of an optical system of a spatial light transmission device, in which 1 is a light emitting element such as a light emitting diode (LED) or a semiconductor laser (LD), 2 is a signal source, 3 is a projection lens,
Reference numeral 4 designates a beam of light emitted from the transmitter, 5 a light receiving lens, 6 a photodetector, and 7 an output device.

[0004] Output from a signal source 2 such as a VTR or CD is passed through an amplifier, an AD converter, an optical modulator, etc. (not shown), and is emitted as an optical signal by a light emitting element 1. The emitted light is turned into substantially parallel light by the projection lens 3. The emitted light 4 from these transmitting parts is transmitted through space toward a receiving part disposed far away, and the light flux taken into the receiving lens of the receiving part is received by a photodetector 6 and converted into an electric signal, which is not shown in the figure. D.A.
The signal passes through a converter, amplifier, etc., and is input to an output device 7 such as a projector or speaker.

[0005]

In the spatial light transmission device as described above, it is necessary to adjust the direction of the transmitter so that the emitted light beam 4 is irradiated to the position of the light receiving lens 5. However, in general, the wavelength of the light emitting element 1 is near-infrared light of about 800 nm, and the emitted light beam 4 is invisible to the naked eye, making it difficult to adjust the emitting direction.

In order to facilitate the adjustment of the output direction, a method can be considered in which the diameter of the output beam 4 is set large in advance at the light-receiving part position and the accuracy of the irradiation position is loosened, but it is clear that the amount of the beam taken into the light-receiving lens 5 is decreases and the signal S
There is a possibility of degrading N. There also arises the problem that the diameter of the emitted light beam varies depending on the transmission distance, that is, the amount of received light varies.

The present invention has been made to solve these problems, and aims to reduce the accuracy of the irradiation position of the irradiation light beam onto the receiving section, and to facilitate the detection of the irradiation position. An object of the present invention is to provide a spatial optical transmission device that realizes highly efficient optical transmission by adjusting the emission direction.

[0008]

[Means for Solving the Problems] In the spatial light transmission device according to the present invention, the transmitting section has a mechanical means that can adjust the distance between the light emitting element and the projection lens, and adjusts the diameter of the irradiated light beam at the receiving section position. The diameter of the irradiated light beam can be increased to reduce the accuracy of the irradiation position within a range that can ensure a sufficient amount of received light.

Further, the transmitting section has a plurality of light emitting elements, and each emitted light beam is arranged so as to irradiate a different location at the receiving section position, so that the accuracy of the irradiation position can be relaxed.

The transmitter is also equipped with a visible light aiming optical system so that the position of the emitted light beam can be visually observed to some extent.

Furthermore, the transmitter has a visible light aiming light emitting element and a signal transmission light emitting element so that the position of the emitted light beam can be visually checked to some extent, and the light emitting elements are combined by a dichroic optical element so that they can be emitted coaxially. It is something.

0012

[Operation] The transmitter configured as described above responds to changes in transmission distance by changing the distance between the light emitting element and the projection lens using an adjustment mechanism, to the extent that the required amount of light received by the receiver can be secured. Since the irradiation beam diameter can be made as large as possible,
The accuracy of irradiation position adjustment can be significantly reduced.

Furthermore, by providing a plurality of light emitting elements in the transmitting section, a plurality of irradiation light beams can be emitted at different positions at the receiving section, so that the accuracy of adjusting the irradiation position can be greatly reduced.

Furthermore, by using a sighting light source that emits a visible wavelength light beam, the position of the irradiated light beam can be easily determined visually.

Furthermore, since the visible wavelength light beam can be irradiated coaxially with the signal transmission light beam by the dichroic optical element, the irradiation position can be accurately determined.

[0016]

[Example] Example 1. FIG. 1 is a block diagram of a light transmission optical system showing an embodiment of the present invention, and 1 to 7 are the same as the conventional device described above. Reference numeral 11 denotes an adjusting means for adjusting the distance between the light emitting element 1 and the projection lens 3. Separate holding parts on the light emitting element side and the projection lens side are connected to each other by a screw structure or a cam structure, and the distance can be adjusted by rotating or sliding. It has a structure that allows it to change.

The transmitting section configured as described above can freely adjust the beam diameter of the emitted beam 4 at the receiving section, and by making the beam diameter sufficiently larger than the aperture of the light receiving lens 5, the positional accuracy of the irradiated beam can be improved. can be alleviated. In other words, as long as the light receiving lens 5 is within the irradiation beam range, the signal can be detected, so it does not matter if the center of the irradiation position is slightly shifted from the light receiving lens. At this time, since the irradiation beam diameter obviously changes due to a change in the transmission distance, the adjustment mechanism 11 is adjusted to correspond to the transmission distance.
The diameter of the irradiation beam can be adjusted using . The diameter of the irradiated light beam can be increased within a range that satisfies the amount of light required by the receiver.

Example 2. In the first embodiment described above, the diameter of the emitted light beam 4 could be expanded only within a range that satisfies the required light amount of the receiver, but a plurality of light emitting elements 1 may be used. FIG. 2 shows an example in which two light emitting elements 1 that emit the same optical signal are used, and the light beams emitted from each light emitting element 1 are projected by the same projection lens 2, and the emitted light beams 4 are placed at different locations depending on the position of the receiver. irradiate. As a result, the area where the receiving section can be placed is doubled.

If a larger number of light emitting elements 1 are used, light can be received with almost no adjustment even if the receiver is arranged. In addition, it is not necessary for each emitted light beam to be irradiated to a completely different position in the receiver, and the amount of received light increases in the overlapping area. It is better to

Example 3. In Examples 1 and 2, the wavelength of the light emitting element 1 is near-infrared light, which cannot be seen with the naked eye, and it was necessary to set the irradiation beam diameter as wide as possible. However, this problem can be solved by separately providing a visible light aiming optical system. In FIG. 3, 8 is a visible light emitting element such as a halogen lamp, LED, or LD, and 9 is a projection lens thereof.

The transmitting section consists of optical systems 1 and 3 for signal transmission and optical systems 8 and 9 for aiming, and the optical axis 10 of the aiming optical system is close to the optical axis of the output beam 4 of the optical system for signal transmission. They should be placed in parallel. Further, if the optical axis 10 is arranged so as to be located inside the irradiated light beam 4 spread out in the receiving section, the position of the emitted light beam 4 can be visually determined.

As a result, the emission direction of the transmitting section can be easily adjusted and the receiving sections 5 and 6 can be irradiated correctly, so the diameter of the emitted light beam 4 at the receiving section does not have to be very large, which is better than the above embodiment. It can receive a large amount of light.

Example 4. In Embodiment 3, the aiming optical system was provided separately from the signal transmission optical system, but a projection lens was also required separately, and the optical axes of the aiming and signal optical systems could not be perfectly aligned, making it impossible to completely correct the irradiation position. cannot know.

FIG. 4 shows an embodiment of the invention in which the optical axes of the aiming optical system and the signal transmission optical system can be made completely coaxial, and 12 is a dichroic optical element having high-pass filter characteristics. The operation of the optical system of the present invention will be explained using the spectral transmittance characteristics and emission spectral characteristics shown in FIG. The emission spectrum a of the light emitting element 1 for signal transmission is near-infrared light with a wavelength of 800 nm or more, and is transmitted according to the transmittance characteristic c of the dichroic element 12. On the other hand, aiming light emitting element 8
spectrum b is reflected by the dichroic element 12. As a result, in FIG. 4, the two light beams are combined and coaxially emitted by the same projection lens 3.

In the present invention, it is possible to visually confirm whether the signal transmission light beam 4 is correctly irradiating a receiving section (not shown), and the irradiation direction can be easily adjusted.

[0026]

[Effects of the Invention] Since the present invention is configured as described above, it produces the effects described below.

By using an adjustment mechanism, the diameter of the irradiated light beam in the receiving section can be adjusted to be larger than that of the light receiving lens to the extent that the necessary amount of light can be secured according to the transmission distance, so that the accuracy of the irradiation position can be greatly reduced.

By providing a plurality of light emitting elements in the transmitting section, a plurality of irradiation light beams can be irradiated at the receiving section, so that the accuracy of the irradiation position can be greatly reduced.

[0029] Furthermore, by equipping the transmitter with a sight,
The position of the irradiated light beam at the receiver can be visually confirmed, making it easy to adjust the emission direction. There is no need to increase the diameter of the irradiated light beam, and the amount of received light can be increased.

Furthermore, since the transmitter is equipped with an optical sight and the dichroic optical element allows the beam to be irradiated coaxially with the signal beam, the position of the irradiated beam at the receiver can be visually confirmed accurately, making it easy to adjust the output direction. . There is no need to increase the diameter of the irradiated light beam, and the amount of received light can be increased.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing a first embodiment of the present invention.

FIG. 2 is a configuration diagram showing a second embodiment of the present invention.

FIG. 3 is a configuration diagram showing a third embodiment of the present invention.

FIG. 4 is a configuration diagram showing a fourth embodiment of the present invention.

FIG. 5 is an explanatory diagram of a dichroic element according to Example 4 of the present invention.

FIG. 6 is a configuration diagram showing a conventional spatial optical transmission device.

[Explanation of symbols]

1 Light emitting element 2 Signal source 3. Projection lens 4 Output luminous flux 5 Light receiving lens 6. Photodetector 7 Output device 8 Aiming light emitting element 9 Aiming projection lens 11 Adjustment mechanism 12 Dichroic optical element

Claims (4)

[Claims] Claim 1: A transmitter comprising a light emitting element and a projection lens;
It consists of a receiving section consisting of a light-receiving element and a light-receiving lens, and the transmitting section has a mechanism for moving the distance between the light-emitting element and the projection lens. A spatial optical transmission device characterized in that it can be adjusted to be larger than the diameter. 2. A transmitter comprising a light emitting element and a projection lens;
It consists of a receiving section consisting of a light receiving element and a light receiving lens, and the transmitting section consists of a plurality of light emitting elements and one projection lens,
1. A spatial light transmission device characterized in that the light beams emitted from each light emitting element illuminate mutually different locations at a receiver position. 3. A transmitter comprising a light emitting element and a projection lens;
The transmitting section includes a light emitting element for signal transmission and a projection lens, and an aiming optical system consisting of a visible wavelength light emitting element and a projection lens. 2. A spatial light transmission device, wherein the optical axis of the optical system is arranged inside the diameter of the light beam emitted from the signal transmission projection lens at the receiving section position. 4. A transmitter comprising a light emitting element and a projection lens;
It consists of a receiving section consisting of a light receiving element and a light receiving lens, and the transmitting section includes a near-infrared wavelength light emitting element for signal transmission, a visible wavelength light emitting element for aiming, and coaxially combining the light beams from the two light emitting elements. 1. A spatial light transmission device comprising a dichroic optical element that projects a beam of light and a projection lens that projects a combined light beam.