JPH1174842A - Photo detector unit, light arrival direction detector and optical transmitter-receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photo detector unit without reducing light receiving amount even when a photodetection element is placed in a horizontal direction by using a special lens. SOLUTION: This photo detector unit 6 is configured with an optical incident plane 26 made of a transparent plate material whose thickness is made almost constant and whose refractive index is 1-2 and one end of which in the lengthwise direction is formed to be a curve, a plate lens member 23 that is formed by applying light shield at least to the optical incident plane 26 and other plane except that opposed to the light incident plane 26, and a photodetection element 28 provided to a face opposite to the optical incident plane 26. Thus, even when the photodetection element 28 is installed in a horizontal direction, the light receiving amount is not reduced and the unit itself is miniaturized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical transmitter / receiver for transmitting and receiving an optical signal through a space, an optical arrival direction detector and an optical detector used for the same.

[0002]

2. Description of the Related Art Generally, in order to smoothly transmit and receive information in a limited space such as in an intelligence building, an optical LAN (Local Area Net) is used.
work). In this optical LAN, information is transmitted using light such as infrared light. For example, an optical signal is transmitted between a transmitting / receiving section provided on a ceiling and a transmitting / receiving section as a node at a desk or the like. The transmission / reception unit is provided, and the transmission / reception unit provided on the ceiling is linked to another transmission / reception unit.

As described above, when performing optical communication between two points in space, it is necessary to first align the optical axes of the light emitting element and the light receiving element between the two points. In particular, when invisible light such as infrared light is used for communication, the optical axis adjustment is limited to a relatively narrow allowable range within several tens of degrees. One has to rely on automatic adjustment by a light arrival direction detector equipped with a detector for knowing the arrival direction. As an example of conventional optical axis alignment, a method shown in FIGS. 19 and 20 is known.

[0004] Reference numeral 1 denotes a transmitting / receiving means provided on the ceiling 2.
It incorporates a light emitting element and a light receiving element. The light transmitting / receiving means 1 emits an optical signal 3 in all directions of a space within a certain area, that is, downward from the ceiling, and the optical signal 3 is detected by a light arrival direction detecting device 4 placed on, for example, a desk or the like. I do. The light detector of the optical transmitter / receiver attached to or integrated with the detection device 4 is directed to the light arrival direction obtained by the detection device 4. I have.

[0005] The detection device 4 is designed to stop down the optical signal 3 with a lens or a reflecting mirror and to detect the optical signal 3 with a photodetector such as a phototransistor or a photodiode. Output only when the optical signal 3 matches the optical axis. Therefore, the range that can be detected in one scan is very narrow, and the opening angle is 10 degrees or less. Therefore, as shown in FIG.
While rotating by degrees, the angle of the optical axis is changed in the elevation direction each time the rotation is made, as shown in FIG. 19, and this is repeated several times to obtain a detection peak point and to communicate with the transmitting / receiving means 1 on the ceiling. The optical axes are aligned with each other.

[0006]

The reason why the detector 4 must be reciprocated several times in the elevation direction every time the detector 4 is rotated in order to detect the direction of arrival of light is as follows.
That is, the detecting device 4 has a light receiving element for detecting information and detecting the direction of arrival of light near one focal point of a lens or a reflecting mirror. The light receiving range for detecting information is suitable for reducing disturbance light. The smaller is better, but the wider is better for detecting the direction of arrival of light. Since it is generally not possible to satisfy both requirements with a single lens or a reflecting mirror, the detection range is narrowed here, giving priority to increasing the accuracy of information detection. By increasing the number of scans in space, the object of detecting the direction of arrival of light is achieved. However, in this case, the number of scans on the space increases as described above, and there is a problem that the search time becomes longer.

In order to solve the above-mentioned problems, the present inventor has disclosed in the earlier application (Japanese Patent Application No. 8-342730) that a light is provided at the back of a slit formed so as to be able to reach from the horizontal direction to the ceiling. An apparatus has been disclosed which is provided with a sensor and which can easily detect an arrival direction of an optical signal by rotating the sensor in a horizontal plane. According to this, it is possible to easily detect the arrival direction of the optical signal only by rotating the device at least once.

However, in the case of this device, the optical sensor is inclined at an angle of approximately 45 degrees with respect to the horizontal direction in order to cover all the optical signals arriving from the direction in which the elevation angle is in the range of 0 to 90 degrees. Therefore, the size, particularly the height, of the device tends to be large, which is not preferable in this type of device in which miniaturization and compactness of the device are required. In particular, the optical sensor is generally provided on the same substrate as a circuit system for amplifying the output of the sensor, but if the optical sensor is provided in an oblique direction as described above, the optical sensor is integrated with the circuit board to be compact. It becomes even more difficult to achieve this.

The present invention focuses on the above problems,
It was created to solve this effectively. SUMMARY OF THE INVENTION An object of the present invention is to provide a light detection unit that does not reduce the amount of received light even when the light detection element is installed in a horizontal direction by using a special lens. Another object of the present invention is to provide a light arrival direction detection device using the above-described light detection unit. Still another object of the present invention is to provide an optical transmission / reception device using the above-mentioned light arrival direction detection device.

[0010]

According to a first aspect of the present invention, there is provided one end face which is made of a plate-shaped transparent material having a substantially constant thickness and a refractive index larger than 1.0, and which is located in a longitudinal direction. Is formed as a curved surface, becomes an incident surface on which light is continuously incident on the upper surface, and is in close contact with the lower surface, the plate-shaped lens member having at least light-shielded surfaces except the lower surface opposed to the incident surface and the upper surface. A light detection unit is constituted by the light detection elements provided in this way.

Thus, for example, light incident on the light incident surface having a certain width from above or obliquely above is refracted by a small angle and reaches the light detecting element, but the light is formed into a curved surface with a relatively shallow elevation angle. When the light is incident on the light incident surface, the light is largely refracted downward, for example, and reaches the light detecting element. Therefore, even if the photodetectors are arranged in the horizontal direction, it is possible to detect the photodetectors with a sufficient amount of light over a wide range from the upper direction to the direction of a relatively small elevation angle. In addition, by forming the light incident surface of the plate-shaped lens member so that its cross section is substantially arc-shaped, also in the thickness direction of the plate-shaped lens member,
Light can be taken in a considerably wide width, and detection can be performed with a sufficient amount of light.

According to a third aspect of the present invention, there is provided the light detecting unit, a turning mechanism for rotating the light detecting unit in a horizontal plane and a vertical plane, and an output of a light detecting element of the light detecting unit. A light arrival direction detection device is constituted by light arrival direction determination means for determining the arrival direction of the optical signal based on the light arrival direction. According to this, the light detection unit is first scanned over a horizontal plane by the turning mechanism, and then,
Scanning is performed over the vertical plane, and the light arrival direction determining means determines the light arrival direction with reference to the output of the light detection unit at this time. Thus, it is possible to easily and quickly determine the light arrival direction including the height. In particular, by providing two such light detection units so as to be back-to-back in the opposite direction, the scanning in the horizontal direction is only rotated by up to 180 degrees, and the height is unknown, but the approximate arrival of light is unknown. The direction can be determined. Therefore, it is possible to more quickly determine the light arrival direction including the height.

According to a fifth aspect of the present invention, there is provided an optical direction-of-arrival detecting device, and an optical transmitting / receiving unit provided on a turning mechanism of the optical direction-of-arrival detecting device and including an optical signal transmitter and a receiver. This is an optical transmission / reception device. According to this, it is possible to establish an optical communication path only by detecting the light arrival direction including the height and directing the optical transmission / reception unit in that direction by the light arrival direction detection device.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a photodetection unit according to the present invention will be described.
An embodiment of an optical direction-of-arrival detecting device using the same and an optical transmitting / receiving device incorporating the same will be described. First, a light arrival direction detection device using a light detection unit will be described. FIG. 1 is a diagram showing a light arrival direction detecting device when detecting light from transmitting / receiving means provided on a ceiling, FIG. 2 is a front view showing the light arrival direction detecting device, and FIG. 3 is a light coming direction detecting device. FIG. 4 is a plan view, FIG. 4 is a perspective view showing two light detection units used in the light arrival direction detection device, FIG. 5 is an enlarged perspective view showing the light detection unit, and FIG. 6 is a side view of the light detection unit shown in FIG. 7 is an enlarged perspective view showing a modified example of the light detection unit, and FIG. 8 is a side view of the light detection unit shown in FIG.
The same components as those described in FIGS. 19 and 20 are denoted by the same reference numerals and described.

In FIG. 1, reference numeral 1 denotes a transmission / reception means as a node provided on a ceiling portion 2, which transmits an optical signal 3 in all directions below the light transmission portion. Receive the signal. The transmission / reception means 1 covers a predetermined area, and is arranged in a large number on a ceiling portion 2 (not shown) to constitute, for example, an optical LAN. The light arrival direction detection device 5 is arranged, for example, on a desk in a room, and detects the arrival direction of the optical signal 3. The light arrival direction detection device 5 includes a pair of light detection units 6 and 6 arranged opposite to each other as shown in FIGS. 2 to 4, and a turning mechanism that enables the light detection units 6 to rotate in a horizontal plane and a vertical plane. 7 and
It mainly comprises a light arrival direction determining means 8 (see FIG. 4) which determines the light arrival direction based on the output from the light detection unit 6, for example, a microcomputer or the like. Although two light detection units 6 are provided here, only one may be provided.

Specifically, the turning mechanism 7 has a turning base 9 for mounting and fixing the pair of light detection units 6, 6 thereon. A support shaft 10 is provided at both ends of the base 9.
And two support columns 12, 12 provided by raising the support shafts 10, 10 from a horizontal turntable 11.
In addition, it is rotatably supported in a vertical plane via bearings 13 and 13. A ring-shaped vertical gear 14 forming a worm wheel is fixed to one of the support shafts 10, 10.
A vertical worm gear 15 rotatably supported on the side is meshed. The rotation shaft of a vertical drive motor 16 is connected to the vertical worm gear 15 directly or indirectly via a speed reducer or the like.
Can be rotated. Therefore, by rotating the worm gear 15, the turning base 9 can be rotated or rocked in a vertical plane in a vertical plane.

On the other hand, the lower surface of the horizontal turntable 11 is fixedly mounted on the upper end of a turning column 17.
Is rotatably supported on a base 18 via a bearing 19, so that the horizontal turntable 11 can be rotated in a horizontal plane. A circular gear 20 forming a worm wheel is fixed in the middle of the turning column 17, and a worm gear 21 rotatably supported on the base 18 side is meshed with the gear 20. The rotation shaft of a horizontal drive motor 22 is connected to the worm gear 21 directly or indirectly via a speed reducer or the like, so that the worm gear 21 can rotate. With the above configuration, the turning base 9 turns in the vertical plane by driving the vertical drive motor 16, and also turns the horizontal turntable 1 by driving the horizontal drive motor 22.
1 rotates in the horizontal plane, and as a result, the turning base 9 turns in the horizontal plane.

Next, the light detection unit 6 will be described. As shown in FIG. 5 and FIG.
Has a plate-shaped lens member 23 made of a plate-shaped transparent material having a substantially constant thickness and a refractive index larger than 1.0 (refractive index: 1.0 to 2.0), for example, resin or glass. I have. Here, for example, an acrylic resin having a refractive index of about 1.49 is used. The plate-like lens member 23 is formed to be horizontally long, and the one end face 24 on the left side in the drawing is formed as an arc-shaped curved surface having a radius of r. The curved surface 24 and the upper surface 25 are continuous and form a light incident surface 26 on which the light (optical signal) 3 is incident. Here, the thickness L1 of the plate-like lens member 23 is set to about 2 mm, the height L2 and the radius r are set to about 5 mm, and the length L3 excluding the curved surface 24 is set to about 3 mm. Have been.

On the lower surface 27 facing the surface 25,
For example, a light detection element 28 such as a photodiode
It is attached to a part of the lower surface 27 so as to be closely attached in the horizontal direction with an adhesive or the like so that the optical signal 3 incident from the light incident surface 26 can be detected. In this case, even if the light detecting element 28 is arranged in the horizontal direction, the traveling direction of the optical signal incident from obliquely upward is bent downward by the refraction of the plate-shaped lens member 23, and the light detecting element 2
Therefore, even if the transmitting / receiving means 1 as a light source is positioned in a horizontal direction and the elevation angle becomes small,
Detection can be performed with a sufficient amount of light.

The other surfaces except the light incident surface 26 and the lower surface 27, that is, both side surfaces 29, 30 and the back surface 31 are subjected to a light-shielding treatment by applying a light absorbing coating or the like. Light cannot enter from other than the incident surface 26. Here, the rear surface 31 may be configured such that a light-reflecting film coating is applied to the rear surface 31 instead of the light-shielding process so that more light that has entered the light incident surface 26 is incident on the light detection element 28. Here, the shape of the light incident surface 26 is flat in the thickness direction of the lens, that is, the cross-sectional shape in the thickness direction is linear. However, the shape is not limited thereto. The cross-sectional shape of the incident surface 26 in the lens thickness direction may be formed to be, for example, an arc-shaped convex portion having a radius r1 so as to have a lens function. According to this, by the light condensing action of the convex light incident surface 26, the thickness direction of the plate-like lens member 23 is
A wider range of light can be collected, and accordingly, a more sufficient amount of light can be collected.

Next, the operation and operation of the light detection unit and the light arrival direction detection device configured as described above will be described. The optical signal 3 (see also FIG. 1) transmitted from the transmitting / receiving means 1 as a light source provided on the ceiling portion 2 is shown in FIGS.
As shown in the figure, the light incident surface 2 having a thickness L1 of only about 2 mm
The light enters the plate-like lens member 23 from 6 and is detected by the photodetector 28 provided in close contact with the lower surface 27. That is, the light incident surface 26 functions as a slit having a width of 2 mm. Here, with the light source 1 positioned diagonally above, the light detection unit 6 is rotated once (360 degrees) in a horizontal plane around the back surface 31.
In this case, the light detection element 28 is as shown in FIG. That is, a high output is obtained in the azimuth where the light source 1 is located (the height, that is, the elevation angle is unknown), and the azimuth can be specified. In this case, as described above, the light incident surface 2
When the light incident surface 26 is convex (see FIG. 8), the light condensing action is greater than when the light incident surface 26 is flat (see FIG. 6), so that a higher output can be obtained.

Next, as shown in FIGS. 10 and 11, it is assumed that the light source 1 relatively moves to the horizontal direction along the locus of the circular arc based on the extension direction of the back surface 31. The moving angle at this time is defined as α. This is the same even if the light source 1 is fixed and the light detection unit 6 is rotated. FIG.
Indicates a case where no plate-shaped lens member is provided and only the light detection element 28 is provided in the horizontal direction. FIG. 12 is a graph showing the output of each photodetector at this time. As is clear from this graph, when there is no lens, as the angle α increases, that is, the light source 1 relatively moves in the horizontal direction. Output, the output decreases gradually, and a sufficient amount of light may not be obtained.

On the other hand, in the case of the light detection unit provided with the plate-like lens member 23 as in the present invention, a sufficiently large amount of light can be obtained over a practical range of angles from 0 to 75 degrees. It turns out to be. In particular, as shown in FIG. 9, a higher output is obtained when the incident surface is formed as a convex lens member. The output value has a peak value when the angle α is near 60 degrees. The angle of the peak value and the practical range of 0 to 75 degrees may be set to appropriate values by appropriately selecting the size of the plate-like lens member, the radius of the curved surface, and the like.

Therefore, as described with reference to FIG. 9, if the azimuth (height is unknown) of the light source 1 is determined by turning the light detection unit 6 in the horizontal plane, as described with reference to FIG. The unit 6 is turned in a vertical plane. As a result, the light source 1 exists in a direction in which the output of the light detection element 28 reaches a peak. In this case, the extension direction of the back surface 31 and the light source 1
Is of course 60 degrees. At this time, a series of arithmetic processing for determining the light arrival direction is performed by the light arrival direction determination means 8. The turning of the light detection unit 6 in the horizontal plane and the vertical plane is performed by using the turning mechanism 7 described with reference to FIGS.

In the above description, only one light detecting unit 6 is provided. In practice, however, as shown in FIG. They are installed symmetrically, back to back. Therefore, when obtaining the azimuth (height is unknown) of the light source 1 as shown in FIG. 9, if the pair of light detection units 6 and 6 is rotated by half a rotation in the horizontal plane, that is, by 180 degrees, any one of them can be obtained. The output peak is detected by one of the light detection units 6. Then, as shown in FIG. 13, when the light source 1 is moved along a circular arc in the vertical plane with the extension direction of the back surface of both units being 0 degree, the two light detection elements 2 at that time are moved.
The outputs of 8 and 28 appear as shown in FIG. That is, in FIG. 13, when the light source 1 is located at 0 degrees, that is, in the zenith direction, the outputs of the two light detection elements 28 and 28 are the same, and when the light source 1 moves to the left (+90 degrees direction), The output of the detection unit gradually increases and decreases after passing the peak value. At this time, the output of the right photodetection unit gradually decreases and becomes zero on the way.

On the other hand, when the light source 1 moves to the right (−90 ° direction), the output of the right photodetection unit gradually increases and decreases after passing the peak value. At this time, the output of the left light detection unit gradually decreases and becomes zero on the way. Therefore, this pair of light detection units 6,
6 is rotated in the vertical plane, and the light source 1 extends in the direction in which the back surface 31 extends when the outputs of the two photodetectors 28 become the same.
Is located, whereby the light arrival direction can be determined. In this case, the light detection unit 6 is set to 1
Since the direction of arrival of light can be determined with a smaller number of rotation operations than in the case where only a single unit is provided, the direction of arrival of light can be determined more quickly and in a shorter time.

According to the present invention, a sufficient amount of light can be detected even if the photodetectors are arranged in the horizontal direction. Therefore, the height and thickness of the photodetection unit can be reduced, and the size of the photodetection unit can be reduced. In addition, thinning can be further promoted.
Further, since the photodetectors can be arranged in the horizontal direction in this manner, the electric circuit system for processing the output can be arranged on the same substrate as the substrate on which the photodetectors are provided. This makes it possible to further reduce the size and the size.

In the above embodiment, the light detection unit and the light arrival direction detection device have been described. Next, an optical transmission and reception device equipped with these devices will be described. 15 is a perspective view showing a main part of the optical transceiver, FIG. 16 is a sectional view of the main part shown in FIG. 15, FIG. 17 is a plan view of the main part shown in FIG. 15, and FIG. It is a figure for explaining a principle. As shown in FIGS. 15 to 17, an optical transmitting / receiving unit 3 constituting a main part of the optical transmitting / receiving apparatus
2 is the turning mechanism 7 described with reference to FIGS.
And is fixedly mounted on a turning base 9 of the vehicle. The optical transmission / reception unit 32 has a receiver 33 for receiving the incoming optical signal 3 and a transmitter 35 for outputting a transmission light 34 modulated by a predetermined signal.

The receiver 33 of the transmission / reception unit 32
An upper surface to be the light receiving surface 36 is substantially horizontal, and the lower surface has a double reflection type condensing lens 37 made of, for example, resin and formed into a curved surface with, for example, a circular arc cross section. The lower surface of the converging lens 37 having an arc-shaped cross section is formed as a concave first reflecting surface 38 by coating the reflecting film in a ring shape.
A concave portion 39 is formed at the center of the upper surface of the condensing lens 37 in an arc shape in cross section, and the surface of the concave portion 39 is coated with a reflective film to form a convex second reflective surface 40. ing.

Immediately below the center of the lower surface of the two-time reflection type condenser lens 37, a photodetector 41 composed of, for example, a photodiode for detecting the condensed light is disposed. Therefore, the first and second reflecting surfaces 38 and 40 are coaxially opposed to each other, and the respective curvatures are such that the optical signal 3 incident from the light receiving surface 36 as shown in FIG. , Are sequentially reflected on the first and second reflecting surfaces 38 and 40 and then condensed on the photodetector 41. The diameter of the condenser lens 37 is set to about 2 to 3 cm, so that the optical system has a relatively narrow directivity. The double reflection type condenser lens 37 is fixedly mounted on the revolving base 9 with the support frame 42 and screws or the like with the light receiving surface 36 facing upward.

From the support frame 42, four support arms 4 extend upward from the central axis of the condenser lens 37.
3 are extended, and an element mounting base 44 is provided at the tip of each arm 43.
I support. On the element mount 44, for example, a semiconductor laser element 45 and a light transmission lens 46 for condensing laser light emitted from the semiconductor laser element 45 into a light beam having a diameter of several mm and emitting the light as transmission light 34 are provided as a transmitter 35. Is provided. In this case, the element mount 44 is connected to the second reflection surface 4.
It is coaxial with 0 to minimize the loss of incoming optical signals. Then, a pair of notches 4 having a predetermined thickness are formed along the diameter direction of the double reflection type condenser lens 37.
7 and 47 are formed, and the pair of light detection units 6 and 6 described with reference to FIGS. 5 to 8 are arranged in this notch so as to be back to back. The light detection units 6 and 6 detect a rough light arrival direction.

The photodetector 41 is constituted by, for example, a four-division sensor comprising a photodiode and a phototransistor. As shown in FIG. 18, the four-divided sensor 41 is formed by dividing a large sensor having a substantially square shape into a cross shape so as to be small square sensor elements A, B, C, and D. The difference between the outputs of a pair of sensor elements on the diagonal line, for example, the sensor elements B and D is obtained by the comparator 48, and this output is used as a vertical rotation signal S1 for rotating the vertical drive motor 16. On the other hand, the difference between the outputs of the sensor elements A and C is obtained by the comparator 49, and this output is used as a horizontal rotation signal S2 for rotating the horizontal drive motor 22. The outputs of the four sensor elements A, B, C, and D are added by the adder 50 and used as a reception signal S3.

Next, the operation of the apparatus of the present invention configured as described above will be described. An optical signal 3 is emitted from the optical transmitting / receiving means 1 shown in FIG. 1 in all directions of the lower hemisphere. In this state, in order to determine the optical communication direction, the horizontal drive motor 22 and the vertical drive motor 16 (see FIGS. 2 and 3) are appropriately rotated and driven as shown in FIGS. The optical transmission / reception unit 32 on which the units 6 and 6 are mounted is scanned within a hemisphere. This allows
The light arrival direction is obtained as described in the operation of the light arrival direction detection device, and this direction is determined as the optical communication direction. In this state, the coarse adjustment of the light arrival direction has been performed. Next, the control for fine adjustment is transferred to the light detector 41 of the receiver 33.

That is, in the state where the coarse adjustment has been performed in this way, as shown in FIG.
The optical signal 3 incident from the light receiving surface 36 of the first
8, the reflected light is reflected by the second reflecting surface 40, and the reflected light is reflected by the lower light detector 41.
Light is collected toward. If the direction of arrival of the light and the optical axis of the photodetector 41 match with high accuracy, the reflected light is formed, for example, as a circular spot 51 at the center on the four-division sensor constituting the photodetector 41 as shown in FIG. It is collected. Therefore,
If the optical axis direction of the receiver 33 is fine-tuned so that the spot 51 is located substantially at the center of the four-divided sensor 41, an optical communication path is established. Then, a laser beam modulated by data or the like is emitted from the semiconductor laser element 45 of the transmitter 35, the laser beam is narrowed down to a thin laser beam by the light transmitting lens 46, output as the transmission light 34, and provided on the ceiling 2. The signal is transmitted to the optical transmitting / receiving means 1 (see FIG. 1). Thereby, for example, communication can be performed between personal computers via the optical transmission / reception means 1.

As described above, according to the present invention, a pair of photodetection units 6 and 6 are provided in the optical transmission / reception unit 32, and the optical transmission / reception unit 32 is provided on the turning mechanism to scan the vertical plane and the horizontal plane. As a result, optical communication can be performed in an arbitrary direction over a wide range within a substantially hemispherical surface. The height direction of the optical system of the receiver 33 is reduced by using a double reflection type condensing lens 37 in which the first and second reflecting surfaces 38 and 40 are provided to face each other. Moreover, the light detection unit 6,
6 is very small and is housed in the condenser lens 37, so that the apparatus can be made smaller and more compact. Therefore, by providing such an optical transmitting and receiving apparatus in a portable personal computer such as a notebook computer, the optical transmitting and receiving apparatus can be freely transported and its function can be increased. The light detection unit 6 provided in the optical transmission / reception device is not limited to the above-described one, and may be formed in another way, for example, by the present applicant (Japanese Patent Application No. 8-342730).
As disclosed in, a unit including a slit and a light receiving element disposed at an angle of 45 degrees in the back may be provided.

[0036]

As described above, according to the light detection unit, the light arrival direction detection device, and the light transmission / reception device of the present invention, the following excellent operational effects can be obtained. According to the photodetecting unit defined in claim 1, light is condensed on the photodetecting element that is in close contact with the lower surface by using the plate-shaped lens member having the curved end surface. Not only the height can be reduced, but also light with a small elevation angle in the light arrival direction can be detected with a sufficient amount of light. In particular, more light can be received by forming the cross section of the light incident surface into an arc shape to have a lens function.

According to the light arrival direction detecting device defined in claim 3, since the light detecting unit is used, the whole device can be reduced in size and size, and quickly and in a short time. The direction of arrival of light can be detected. In particular, by providing two light detection units back to back, it is possible to more quickly detect the light arrival direction. According to the optical transmission / reception device defined in claim 5, since the above-described light detection unit and light arrival direction detection device are used, not only can the size and size of the device be reduced, but also quickly and in a short time. An optical communication path can be established.

[Brief description of the drawings]

FIG. 1 is a diagram showing a light arrival direction detecting device when detecting light from a transmitting / receiving means provided on a ceiling portion.

FIG. 2 is a front view showing a light arrival direction detection device.

FIG. 3 is a plan view showing a light arrival direction detection device.

FIG. 4 is a perspective view showing two light detection units used in the light arrival direction detection device.

FIG. 5 is an enlarged perspective view showing a light detection unit.

FIG. 6 is a side view of the light detection unit shown in FIG.

FIG. 7 is an enlarged perspective view showing a modified example of the light detection unit.

FIG. 8 is a side view of the light detection unit shown in FIG.

FIG. 9 is a diagram illustrating an output when the light detection unit is rotated once in a horizontal plane.

FIG. 10 is a diagram for explaining a situation in which the light source is relatively moved in a vertical plane with respect to the light detection unit.

FIG. 11 is a diagram for explaining a situation where a light source is relatively moved in a vertical plane with respect to a photodetector that does not use a plate-shaped lens member.

FIG. 12 is a diagram illustrating an output of a photodetector when a light source is relatively moved within a vertical plane.

FIG. 13 is a diagram for explaining a situation in which a light source is relatively moved within a vertical plane with respect to a pair of light detection units.

14 is a diagram illustrating an output of each light detection element when the light source illustrated in FIG. 13 is relatively moved.

FIG. 15 is a perspective view showing a main part of the optical transceiver.

16 is a sectional view of a main part shown in FIG.

FIG. 17 is a plan view of a main part shown in FIG.

FIG. 18 is a diagram for explaining the principle of a light receiving sensor used for a receiver.

FIG. 19 is a diagram showing a general relationship between a transmission / reception means (light source) and a light arrival direction detection device.

20 is a diagram showing a scanning method of the detection device shown in FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Transmission / reception means, 3 ... Optical signal, 5 ... Light arrival direction detection apparatus, 6 ... Light detection unit, 7 ... Turning mechanism, 8 ... Light arrival direction determination means, 9 ... Turning base, 10 ... Horizontal turntable, 16 …
Vertical drive motor, 22 horizontal drive motor, 23 plate-shaped lens member, 24 end surface (curved surface), 25 upper surface, 26 light incident surface, 28 light detection element, 32 light transmission / reception unit,
33: Receiver, 35: Transmitter, 37: Double reflection type condenser lens, 38: First reflection surface, 40: Second reflection surface, 41
... photodetector, 45 ... semiconductor laser element.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takera Sasura 3--12 Moriyacho, Kanagawa-ku, Yokohama, Kanagawa Prefecture Inside of Victor Company of Japan, Ltd. (72) Inventor Junichi Kubota 3-chome Moriyacho, Kanagawa-ku, Yokohama, Kanagawa No. 12 Inside Victor Company of Japan (72) Inventor Masahiko Okabe 3-12 Moriyacho, Kanagawa-ku, Yokohama City, Kanagawa Prefecture

Claims (5)

[Claims] 1. A light incident surface formed of a plate-shaped transparent material having a substantially constant thickness and a refractive index of 1 to 2 and having one end in a longitudinal direction formed into a curved surface, the light incident surface and the light incident surface. A light detection unit, comprising: a plate-shaped lens member having at least light-shielded surfaces other than a surface facing the surface; and a light detection element provided on a surface facing the light incident surface. 2. The light detection unit according to claim 1, wherein the light incident surface has a substantially arc-shaped cross section and has a lens function. 3. The light detection unit according to claim 1, wherein the light detection unit is rotatable in a horizontal plane and a vertical plane, and based on an output of a light detection element of the light detection unit. And a light arrival direction determining means for determining a direction of arrival of the optical signal. 4. The light detection unit is arranged in a pair,
4. The light arrival direction detecting device according to claim 3, wherein the curved end surfaces of the light incident surface are located in opposite directions, and are arranged symmetrically in the longitudinal direction. 5. An optical direction-of-arrival detecting device according to claim 3 or 4, and an optical transmitting / receiving unit provided on a turning mechanism of the optical direction-of-arrival detecting device and including an optical signal transmitter and a receiver. An optical transmitting and receiving device characterized by being performed.