U.S. patent application number 09/732897 was filed with the patent office on 2001-07-19 for optical transmitting and receiving apparatus.
This patent application is currently assigned to VICTOR COMPANY OF JAPAN, LTD.. Invention is credited to Nagashima, Tomoyasu, Sato, Fumio, Sato, Masamichi, Shou, Toshiaki, Taninaka, Kazumasa, Yunoki, Yoshiaki.
Application Number | 20010008454 09/732897 |
Document ID | / |
Family ID | 13663842 |
Filed Date | 2001-07-19 |
United States Patent
Application |
20010008454 |
Kind Code |
A1 |
Shou, Toshiaki ; et
al. |
July 19, 2001 |
Optical transmitting and receiving apparatus
Abstract
In an optical transmitting and receiving apparatus, an light
transmitting and receiving unit includes a light emitting element,
a light transmitting lens, a light receiving lens, and a
photosensitive element. The light emitting element outputs light.
The light outputted from the light emitting element passes through
the light transmitting lens before leaving the light transmitting
and receiving unit as outgoing light. The light receiving lens
concentrates incoming light on the photosensitive element. A first
support member is operative for supporting the light transmitting
and receiving unit, and for allowing the light transmitting and
receiving unit to rotate about a first axis. A first rotary
mechanism connected to the light transmitting and receiving unit
and the first support member is operative for rotating the light
transmitting and receiving unit about the first axis. A second
support member is operative for supporting the light transmitting
and receiving unit on a cantilever basis, and for allowing the
light transmitting and receiving unit to rotate about a second axis
perpendicular to the first axis. A second rotary mechanism
connected to the light transmitting and receiving unit and the
second support member is operative for rotating the light
transmitting and receiving unit about the second axis.
Inventors: |
Shou, Toshiaki;
(Sagamihara-shi, JP) ; Sato, Fumio;
(Sagamihara-shi, JP) ; Yunoki, Yoshiaki; (Tokyo,
JP) ; Nagashima, Tomoyasu; (Kashiwa-shi, JP) ;
Sato, Masamichi; (Tokyo, JP) ; Taninaka,
Kazumasa; (Ichikawa-shi, JP) |
Correspondence
Address: |
PARKHURST & WENDEL, L.L.P.
Suite 210
1421 Prince Street
Alexandria
VA
22314-2805
US
|
Assignee: |
VICTOR COMPANY OF JAPAN,
LTD.
|
Family ID: |
13663842 |
Appl. No.: |
09/732897 |
Filed: |
December 11, 2000 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
09732897 |
Dec 11, 2000 |
|
|
|
09037860 |
Mar 10, 1998 |
|
|
|
Current U.S.
Class: |
398/135 ;
398/128 |
Current CPC
Class: |
H04B 10/801
20130101 |
Class at
Publication: |
359/152 ;
359/163 |
International
Class: |
H04B 010/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 28, 1997 |
JP |
9-78506 |
Claims
What is claimed is:
1. An optical transmitting and receiving apparatus comprising: a
light transmitting and receiving unit including 1) a light emitting
element, 2) a light transmitting lens, 3) a light receiving lens,
and 4) a photosensitive element, wherein the light emitting element
outputs light, and the light outputted from the light emitting
element passes through the light transmitting lens before leaving
the light transmitting and receiving unit as outgoing light, and
wherein the light receiving lens concentrates incoming light on the
photosensitive element; a first support member for supporting the
light transmitting and receiving unit, and for allowing the light
transmitting and receiving unit to rotate about a first axis; a
first rotary mechanism connected to the light transmitting and
receiving unit and the first support member for rotating the light
transmitting and receiving unit about the first axis; a second
support member for supporting the light transmitting and receiving
unit on a cantilever basis, and for allowing the light transmitting
and receiving unit to rotate about a second axis perpendicular to
the first axis; and a second rotary mechanism connected to the
light transmitting and receiving unit and the second support member
for rotating the light transmitting and receiving unit about the
second axis.
2. An optical transmitting and receiving apparatus comprising: a
light transmitting and receiving unit including 1) a light emitting
element, 2) a light transmitting lens, 3) a light receiving lens,
and 4) a photosensitive element, wherein the light emitting element
outputs light, and the light outputted from the light emitting
element passes through the light transmitting lens before leaving
the light transmitting and receiving unit as outgoing light, and
wherein the light receiving lens concentrates incoming light on the
photosensitive element; a first shaft connected to the light
transmitting and receiving unit for rotation together therewith; a
first support member for supporting the first shaft, and for
allowing the first shaft to rotate; a first rotary mechanism
connected to the first shaft and the first support member for
rotating the first shaft relative to the first support member, a
second shaft being perpendicular to the first shaft and being
connected to a base of the first support member for rotation
together with the first support member; a second support member for
supporting the first support member via the second shaft, and for
allowing the first support member to rotate; and a second rotary
mechanism connected to the second shaft and the second support
member for rotating the second shaft relative to the second support
member.
3. An optical transmitting and receiving apparatus as recited in
claim 1, wherein the second axis is substantially horizontal.
4. An optical transmitting and receiving apparatus as recited in
claim 1, wherein each of the first and second rotary mechanisms
includes a worm, a wheel gear in mesh with the worm, and a pressing
mechanism for pressing the worm against the wheel gear.
5. An optical transmitting and receiving apparatus as recited in
claim 1, further comprising: first and second arms provided on the
first support member and opposing each other; a transmission-side
flexible cable extending along the first arm and reaching the light
emitting element; and a reception-side flexible cable leading from
the photosensitive element and extending along the second arm.
6. An optical transmitting and receiving apparatus as recited in
claim 2, further comprising a first bearing supporting the first
shaft and being composed of electrically-conductive members, and a
second bearing supporting the second shaft and being composed of
electrically-conductive members.
7. An optical transmitting and receiving apparatus comprising: a
light transmitting and receiving unit including 1) a light emitting
element, 2) a light transmitting lens, 3) a light receiving lens,
and 4) a photosensitive element, wherein the light emitting element
outputs light, and the light outputted from the light emitting
element passes through the light transmitting lens before leaving
the light transmitting and receiving unit as outgoing light,
wherein the light receiving lens concentrates incoming light on the
photosensitive element, and wherein the light transmitting lens and
the light receiving lens are arranged side by side and face in
equal directions; and a rotary mechanism for rotating the light
transmitting and receiving unit about an axis; wherein a distance
between the axis and a top of the light transmitting lens is
smaller than a distance between the axis and a top of the light
receiving lens.
8. An optical transmitting and receiving apparatus comprising: a
light transmitting and receiving unit including 1) a light emitting
element, 2) a light transmitting lens, 3) a light receiving lens,
and 4) a photosensitive element, wherein the light emitting element
outputs light, and the light outputted from the light emitting
element passes through the light transmitting lens before leaving
the light transmitting and receiving unit as outgoing light,
wherein the light receiving lens concentrates incoming light on the
photosensitive element, and wherein the light transmitting lens and
the light receiving lens are arranged side by side and face in
equal directions; a first rotary mechanism for rotating the light
transmitting and receiving unit about a first axis; a second rotary
mechanism for rotating the light transmitting and receiving unit
about a second axis perpendicular to the first axis; wherein a
center of the light receiving lens is on the second axis, and the
light transmitting lens is smaller in diameter than the light
receiving lens, and wherein a center of the light transmitting lens
is offset from the second axis by a predetermined distance to
provide a space at a side of the light transmitting lens, the space
accommodating the first rotary mechanism.
9. An optical transmitting and receiving apparatus comprising: a
light transmitting and receiving unit including 1) a light emitting
element, 2) a light transmitting lens, 3) a light receiving lens,
and 4) a photosensitive element, wherein the light emitting element
outputs light, and the light outputted from the light emitting
element passes through the light transmitting lens before leaving
the light transmitting and receiving unit as outgoing light,
wherein the light receiving lens concentrates incoming light on the
photosensitive element, and wherein the light transmitting lens and
the light receiving lens are arranged side by side and face in
equal directions; a rotary mechanism for rotating the light
transmitting and receiving unit; a dome-shaped cover covering the
light transmitting and receiving unit, and conducting light of a
predetermined wavelength while blocking light of a wavelength
different from the predetermined wavelength; and a cylindrical
visor connected to the light transmitting lens and having an end
close to an inner surface of the cover.
10. An optical transmitting and receiving apparatus as recited in
claim 9, wherein the end of the visor and the inner surface of the
cover are substantially equal in radius of curvature.
11. An optical transmitting and receiving apparatus as recited in
claim 9, further comprising a cylindrical visor connected to the
light receiving lens, wherein the visor connected to the light
transmitting lens is integral with the visor connected to the light
receiving lens.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This invention relates to an apparatus for transmitting and
receiving optical signals which can be used in, for example, a
wireless communication network.
[0003] 2. Description the Related Art
[0004] In a wired LAN (local area network), terminal devices are
connected to each other via wires. The terminal devices can
communicate with each other via the wires.
[0005] It is known to combine a wired IAN and a wireless
communication network. For example, a wired LAN is additionally
provided with an access point device (a gateway device) which can
execute both wired communication and wireless communication. The
access point device is connected via wires to normal terminal
devices in the wired LAN. The access point device can communicate
with the normal terminal devices in the wired LAN via the wires.
Also, the access point device can execute wireless communication
with terminal devices in a wireless communication network. In this
case, the wired LAN and the wireless communication network are
connected via the access point device (the gateway device). In
addition, the access point device is a member of the wired LAN as
well as a member of the wireless communication network.
[0006] According to an example of the wireless communication
network, the access point device (the gateway device) and the
terminal devices can communicate with each other by using optical
signals such as infrared-light signals.
[0007] Japanese patent laid open number (Japanese published
unexamined patent application) 8-139675 discloses an optical
transmitting and receiving apparatus which is used in an optical
communication network. The apparatus in Japanese patent laid open
number 8-139675 includes a light transmitting and receiving unit
which has a light transmitting mirror and a light receiving mirror
coaxial with each other. The light transmitting and receiving unit
can be rotated about a vertical axis and also about a horizontal
axis. The rotation of the light transmitting and receiving unit
enables its optical axis to be accorded with an optical axis of a
communication opposite party.
[0008] Japanese patent laid open number 8-139675 also discloses a
light transmitting and receiving unit which has a light
transmitting mirror and a light receiving mirror arranged side by
side along a vertical direction.
SUMMARY OF THE INVENTION
[0009] It is a first object of this invention to provide an optical
transmitting and receiving apparatus which is lighter in weight
than a prior-art apparatus.
[0010] It is a second object of this invention to provide an
optical transmitting and receiving apparatus which is smaller in
size than a prior-art apparatus.
[0011] It is a third object of this invention to provide an optical
transmitting and receiving apparatus whose optical axis can be
varied at a speed higher than the speed of variation of an optical
axis of a prior-art apparatus.
[0012] A first aspect of this invention provides an optical
transmitting and receiving apparatus comprising a light
transmitting and receiving unit including 1) a light emitting
element, 2) a light transmitting lens, 3) a light receiving lens,
and 4) a photosensitive element, wherein the light emitting element
outputs light, and the light outputted from the light emitting
element passes through the light transmitting lens before leaving
the light transmitting and receiving unit as outgoing light, and
wherein the light receiving lens concentrates incoming light on the
photosensitive element; a first support member for supporting the
light transmitting and receiving unit, and for allowing the light
transmitting and receiving unit to rotate about a first axis; a
first rotary mechanism connected to the light transmitting and
receiving unit and the first support member for rotating the light
transmitting and receiving unit about the first axis; a second
support member for supporting the light transmitting and receiving
unit on a cantilever basis, and for allowing the light transmitting
and receiving unit to rotate about a second axis perpendicular to
the first axis; and a second rotary mechanism connected to the
light transmitting and receiving unit and the second support member
for rotating the light transmitting and receiving unit about the
second axis.
[0013] A second aspect of this invention provides an optical
transmitting and receiving apparatus comprising a light
transmitting and receiving unit including 1) a light emitting
element, 2) a light transmitting lens, 3) a light receiving lens,
and 4) a photosensitive element, wherein the light emitting element
outputs light, and the light outputted from the light emitting
element passes through the light transmitting lens before leaving
the light transmitting and receiving unit as outgoing light, and
wherein the light receiving lens concentrates incoming light on the
photosensitive element; a first shaft connected to the light
transmitting and receiving unit for rotation together therewith; a
first support member for supporting the first shaft, and for
allowing the first shaft to rotate; a first rotary mechanism
connected to the first shaft and the first support member for
rotating the first shaft relative to the first support member; a
second shaft being perpendicular to the first shaft and being
connected to a base of the first support member for rotation
together with the first support member; a second support member for
supporting the first support member via the second shaft, and for
allowing the first support member to rotate; and a second rotary
mechanism connected to the second shaft and the second support
member for rotating the second shaft relative to the second support
member.
[0014] A third aspect of this invention is based on the first
aspect thereof, and provides an optical transmitting and receiving
apparatus wherein the second axis is substantially horizontal.
[0015] A fourth aspect of this invention is based on the first
aspect thereof, and provides an optical transmitting and receiving
apparatus wherein each of the first and second rotary mechanisms
includes a worm, a wheel gear in mesh with the worm, and a pressing
mechanism for pressing the worm against the wheel gear.
[0016] A fifth aspect of this invention is based on the first
aspect thereof, and provides an optical transmitting and receiving
apparatus further comprising first and second arms provided on the
first support member and opposing each other; a transmission-side
flexible cable extending along the first arm and reaching the light
emitting element; and a reception-side flexible cable leading from
the photosensitive element and extending along the second arm.
[0017] A sixth aspect of this invention is based on the second
aspect thereof, and provides an optical transmitting and receiving
apparatus further comprising a first bearing supporting the first
shaft and being composed of electrically-conductive members, and a
second bearing supporting the second shaft and being composed of
electrically-conductive members.
[0018] A seventh aspect of this invention provides an optical
transmitting and receiving apparatus comprising a light
transmitting and receiving unit including 1) a light emitting
element, 2) a light transmitting lens, 3) a light receiving lens,
and 4) a photosensitive element, wherein the light emitting element
outputs light, and the light outputted from the light emitting
element passes through the light transmitting lens before leaving
the light transmitting and receiving unit as outgoing light,
wherein the light receiving lens concentrates incoming light on the
photosensitive element, and wherein the light transmitting lens and
the light receiving lens are arranged side by side and face in
equal directions;, and a rotary mechanism for rotating the light
transmitting and receiving unit about an axis: wherein a distance
between the axis and a top of the light transmitting lens is
smaller than a distance between the axis and a top of the light
receiving lens.
[0019] An eighth aspect of this invention provides an optical
transmitting and receiving apparatus comprising a light
transmitting and receiving unit including 1) a light emitting
element, 2) a light transmitting lens, 3) a light receiving lens,
and 4) a photosensitive element, wherein the light emitting element
outputs light, and the light outputted from the light emitting
element passes through the light transmitting lens before leaving
the light transmitting and receiving unit as outgoing light,
wherein the light receiving lens concentrates incoming light on the
photosensitive element, and wherein the light transmitting lens and
the light receiving lens are arranged side by side and face in
equal directions; a first rotary mechanism for rotating the light
transmitting and receiving unit about a first axis; a second rotary
mechanism for rotating the light transmitting and receiving unit
about a second axis perpendicular to the first axis; wherein a
center of the light receiving lens is on the second axis, and the
light transmitting lens is smaller in diameter than the light
receiving lens, and wherein a center of the light transmitting lens
is offset from the second axis by a predetermined distance to
provide a space at a side of the light transmitting lens, the space
accommodating the first rotary mechanism.
[0020] A ninth aspect of this invention provides an optical
transmitting and receiving apparatus comprising a light
transmitting and receiving unit including 1) a light emitting
element, 2) a light transmitting lens, 3) a light receiving lens,
and 4) a photosensitive element, wherein the light emitting element
outputs light, and the light outputted from the light emitting
element passes through the light transmitting lens before leaving
the light transmitting and receiving unit as outgoing light,
wherein the light receiving lens concentrates incoming light on the
photosensitive element, and wherein the light transmitting lens and
the light receiving lens are arranged side by side and face in
equal directions; a rotary mechanism for rotating the light
transmitting and receiving unit; a dome-shaped cover covering the
light transmitting and receiving unit, and conducting light of a
predetermined wavelength while blocking light of a wavelength
different from the predetermined wavelength; and a cylindrical
visor connected to the light transmitting lens and having an end
close to an inner surface of the cover.
[0021] A tenth aspect of this invention is based on the ninth
aspect thereof, and provides an optical transmitting and receiving
apparatus wherein the end of the visor and the inner surface of the
cover are substantially equal in radius of curvature.
[0022] An eleventh aspect of this invention is based on the ninth
aspect thereof, and provides an optical transmitting and receiving
apparatus further comprising a cylindrical visor connected to the
light receiving lens, wherein the visor connected to the light
transmitting lens is integral with the visor connected to the light
receiving lens.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] FIG. 1 is a sectional diagram of a prior-art optical
transmitting and receiving apparatus.
[0024] FIG. 2 is a sectional view of a light transmitting and
receiving unit in the prior-art apparatus of FIG. 1.
[0025] FIG. 3 is a perspective view of an optical transmitting and
receiving apparatus according to an embodiment of this
invention.
[0026] FIG. 4 is a perspective exploded view of the optical
transmitting and receiving apparatus in FIG. 3.
[0027] FIG. 5 is a top view of the optical transmitting and
receiving apparatus in FIG. 3 from which a cover is removed.
[0028] FIG. 6 is a side view of a portion of the optical
transmitting and receiving apparatus in FIG. 5.
[0029] FIG. 7 is a side view, partially in section, of a first
pressing mechanism in the optical transmitting and receiving
apparatus in FIG. 6.
[0030] FIG. 8 is a view in the direction of the arrow A8 in FIG.
6.
[0031] FIG. 9 is an elevation view of a second pressing mechanism
in the optical transmitting and receiving apparatus in FIG. 8.
[0032] FIG. 10 is a sectional view taken along the line A10-A10 in
FIG. 5.
[0033] FIG. 11 is a top view of the optical transmitting and
receiving apparatus in FIG. 5 to which flexible cables are
added.
[0034] FIG. 12 is a sectional diagram of a light transmitting lens,
a light receiving lens, a light emitting element, and a light
receiving element in the optical transmitting and receiving
apparatus in FIG. 5 which are in conditions where the light
transmitting lens and the light receiving lens face directly
upward.
[0035] FIG. 13 is a sectional diagram of the light transmitting
lens, the light receiving lens, the light emitting element, and the
light receiving element in conditions which occur when they are
rotated counterclockwise from the positions in FIG. 12 through a
given angle.
[0036] FIG. 14 is a sectional diagram of the light transmitting
lens, the light receiving lens, the light emitting element, and the
light receiving element in conditions which occur when they are
rotated clockwise from the positions in FIG. 12 through a given
angle.
[0037] FIG. 15 is a perspective diagram of a portion of the optical
transmitting and receiving apparatus in FIG. 5.
[0038] FIG. 16 is a diagrammatic top view of a light transmitting
lens, a light receiving lens, and a motor.
[0039] FIG. 17 is a diagrammatic top view of a light transmitting
lens, a light receiving lens, and a motor in the optical
transmitting and receiving apparatus in FIG. 5.
[0040] FIG. 18 is a sectional diagram of a light transmitting lens,
a light receiving lens, a block, a light emitting element, and a
photosensitive element.
[0041] FIG. 19 is a sectional diagram of a light transmitting lens,
a light receiving lens, a block, a light emitting element, and a
photosensitive element in the optical transmitting and receiving
apparatus in FIG. 5.
[0042] FIG. 20 is a sectional view of a cover, a visor, and a light
emitting and receiving unit in the optical transmitting and
receiving apparatus in FIG. 3.
[0043] FIG. 21 is a sectional view, corresponding to FIG. 20, of
the cover, the visor, and the light emitting and receiving unit,
and paths of light.
[0044] FIG. 22 is a diagram of a light transmitting and receiving
unit, arms, a shaft, and a transmission-reception flexible
cable.
[0045] FIG. 23 is a sectional view of the transmission-reception
flexible cable which is taken along the line A23-A23 in FIG.
22.
[0046] FIG. 24 is a diagram of a light transmitting and receiving
unit, arms, a shaft, a transmission-side flexible cable, and a
reception-side flexible cable in the optical transmitting and
receiving apparatus of FIG. 11.
[0047] FIG. 25 is a sectional view of the reception-side flexible
cable which is taken along the line A25-A25 in FIG. 24.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0048] A prior-art apparatus will be explained for a better
understanding of this invention. FIG. 1 shows a prior-art optical
transmitting and receiving apparatus disclosed in Japanese patent
laid open number 8-139675.
[0049] With reference to FIG. 1, the prior-art apparatus includes a
light transmitting mirror 101 and a light receiving mirror 102
which are coaxially provided in a light transmitting and receiving
unit 103. The light transmitting and receiving unit 103 can be
moved to provide reliable bidirectional optical communication with
an apparatus of a communication opposite party.
[0050] The prior-art apparatus of FIG. 1 includes a base 105. A
fixed gear 106 is mounted on a vertical shaft 107 rotatably
supported on a central area of the base 105. A bearing block 108
rotatably extending around the vertical shaft 107 is supported on
the fixed gear 106. A rotary base 109 is attached to the bearing
block 108. A frame 110 is attached to the rotary base 109.
Accordingly, the frame 110 rotates together with the rotary base
109. Horizontal shafts 111 are rotatably supported by upper
portions of the frame 110. The light transmitting and receiving
unit 103 is supported by the horizontal shafts 111.
[0051] In the prior-art apparatus of FIG. 1, a motor 112 is mounted
on the rotary base 109. A gear mounted on an output shaft of the
motor 112 meshes with the fixed gear 106. As the output shaft of
the motor 112 rotates, the rotary base 109 is turned relative to
the fixed gear 106. Accordingly, the motor 112 serves to turn the
rotary base 109 about the axis of the vertical shaft 107. A motor
113 is mounted on the rotary base 109. A speed-reducing gear set
114 connects the output shaft of the motor 113 and a gear 115
provided on the light transmitting and receiving unit 103. The gear
115 extends around one of the horizontal shafts 111. As the output
shaft of the motor 113 rotates, the gear 115 rotates about the axis
of the related horizontal shaft 111. The light transmitting and
receiving unit 103 rotates together with the gear 115.
[0052] In the prior-art apparatus of FIG. 1, the light transmitting
and receiving unit 103 can be rotated by the motor 113 about a
horizontal axis "X". Also, the light transmitting and receiving
unit 103 can be rotated by the motor 112 about a vertical axis "Z".
The rotation of the light transmitting and receiving unit 103
enables its optical axis to be accorded with an optical axis of a
communication opposite party. The optical-axis accordance enables
reliable bidirectional optical communication between the prior-art
apparatus and the communication opposite party.
[0053] As shown in FIG. 2, the light transmitting and receiving
unit 103 in the prior-art apparatus includes a box casing 116 which
accommodates the light transmitting mirror 101 and the light
receiving mirror 102. The light transmitting mirror 101 includes a
small parabolic reflecting mirror. The light receiving mirror 102
includes a large parabolic reflecting mirror. The light
transmitting mirror 101 and the light receiving mirror 102 are
coaxial with each other. The light transmitting and receiving unit
103 includes a light emitting element 117. Light is outputted from
the light emitting element 117 toward the light transmitting mirror
101. The light reaches the light transmitting mirror 101, being
reflected thereby before travelling forward from the light
transmitting and receiving unit 103 as an outgoing parallel light
beam. The light transmitting and receiving unit 103 also includes a
reflecting mirror 118 and a photosensitive element 119. Incoming
light enters the light transmitting and receiving unit 103 and then
meets the light receiving mirror 102. The incoming light is
successively reflected by the light receiving mirror 102 and the
reflecting mirror 118 before reaching the photosensitive element
119. The light receiving mirror 102 serves to concentrate the
incoming light on the photosensitive element 119.
[0054] In the prior-art apparatus of FIG. 1, the light transmitting
mirror 101 and the light receiving mirror 102 tend to be heavy in
weight. Accordingly, the speed of movement of the light
transmitting and receiving unit 103 is limited to a relatively low
speed. The light receiving mirror 102 tends to be large in
size.
[0055] An embodiment of this invention will be explained
hereinafter. FIG. 3 shows an optical transmitting and receiving
apparatus 1 according to an embodiment of this invention.
[0056] With reference to FIG. 3, the optical transmitting and
receiving apparatus 1 includes a casing 2 made of resin. The casing
2 has a base and a cover 3. The cover 3 is detachably connected to
the base of the casing 2. Preferably, the cover 3 has a dome shape.
The cover 3 is made of resin. The cover 3 is transparent with
respect to near infrared light but is opaque with respect to
visible light. According to another example, the cover 3 absorbs
visible light, and is transparent with respect to near infrared
light having a wavelength of 700 nm or longer.
[0057] The optical transmitting and receiving apparatus 1 has a
shape approximately corresponding to a rectangular parallelepiped
with one curved side. The base of the casing 2 has a sufficient
area. The height of the apparatus 1 is relatively small.
Accordingly, the apparatus 1 is effectively prevented from rolling.
This is advantageous in maintaining a high reliability of light
transmission and light reception by the apparatus 1.
[0058] As shown in FIG. 4, the optical transmitting and receiving
apparatus 1 includes a light transmitting and receiving unit 10, a
first support member 20, a first rotary mechanism 30, a second
support member 40, and a second rotary mechanism 50. The casing 2
which includes the cover 3 (see FIG. 3) houses these devices 10,
20, 30, 40, and 50.
[0059] The light transmitting and receiving unit 10 includes a
light emitting element 11 (see FIG. 10), a light transmitting lens
12, a light receiving lens 13, and a photosensitive element 14 (see
FIG. 10). The light emitting element 11 is designed to output near
infrared light which can efficiently pass through the cover 3. The
photosensitive element 14 is designed to sense near infrared light
which can efficiently pass through the cover 3. Light outputted
from the light emitting element 11 (see FIG. 10) passes through the
light transmitting lens 12, and then travels forward from the light
transmitting and receiving unit 10 as outgoing light. Incoming
light which enters the light transmitting and receiving unit 10
passes through the light receiving lens 13. The incoming light is
concentrated by the light receiving lens 13 on the photosensitive
element 14 (see FIG. 10).
[0060] The first support member 20 has a forked shape. The first
support member 20 has a pair of left-hand and right-hand arms 21
and 22 extending parallel to each other. The light transmitting and
25 receiving unit 10 is supported by a pair of left-hand and
right-hand shafts 15A and 15B which are rotatably borne by the arms
21 and 22 of the first support member 20 respectively. The shafts
15A and 15B axially align with each other. The shafts 15A and 15B
are fixed to a body of the light transmitting and receiving unit
10. As will be made clear later, the left-hand shaft 15A is a
driven shaft. The light transmitting and receiving unit 10 rotates
in accordance with rotation of the left-hand shaft 15A.
[0061] The first rotary mechanism 30 is connected to the first
support member 20. The first rotary mechanism 30 serves to rotate
the left-hand shaft 15A. Thus, the first rotary mechanism 30 serves
to rotate the light transmitting and receiving unit 10 about the
axes of the shafts 15A and 15B.
[0062] The second support member 40 is connected to a shaft 24
extending perpendicular to the shafts 15A and 15B. The shaft 24 is
provided on a base portion of the first support member 20. The
shaft 24 is secured to the first support member 20. Accordingly,
the first support member 20 rotates together with the shaft 24. The
second support member 40 bears the first support member 20 via the
shaft 24 on a cantilever basis. The first support member 20 can be
rotated relative to the second support member 40 about the axis of
the shaft 24.
[0063] It is preferable that the axis of the shaft 24 is exactly or
substantially (approximately) in a horizontal plane. The axis of
the shaft 24 may be inclined with respect to the horizontal plane
by a predetermined angle.
[0064] The second rotary mechanism 50 is connected to the second
support member 40. The second rotary mechanism 50 couples with the
shaft 24. The second rotary mechanism 50 serves to rotate the shaft
24 and the first support member 20 relative to the second support
member 40. Thus, the second rotary mechanism 50 serves to rotate
the light transmitting and receiving unit 10 about the axis of the
shaft 24.
[0065] The light receiving lens 13 is greater in diameter than the
light transmitting lens 12. Both the light transmitting lens 12 and
the light receiving lens 13 include aspherical lenses. The focal
lengths of such aspherical lenses can be significantly shorter than
those of spherical lenses. Accordingly, the light transmitting lens
12 and the light receiving lens 13 enable a small height of the
light transmitting and receiving unit 10. The light transmitting
lens 12 and the light receiving lens 13 are surrounded by a visor
65 which will be explained later.
[0066] The first support member 20 is a frame having the left-hand
and right-hand arms 21 and 22, a back plate 23, and the shaft 24.
The first support member (the frame) 20 has a forked shape in a
plan view. The left-hand and right-hand arms 21 and 22 are parallel
to each other. The back plate 23 is perpendicular to the left-hand
and right-hand arms 21 and 22. The left-hand and right-hand arms 21
and 22 extend from a front surface of the back plate 23. The
left-hand and right-hand arms 21 and 22 are supported by the back
plate 23. The shaft 24 projects from a rear surface of the back
plate 23 in a direction opposite to the directions along which the
left-hand and right-hand arms 21 and 22 extend from the front
surface of the back plate 23. The shaft 24 serves as a shaft on a
base portion of the first support member 20.
[0067] An approximately L-shaped side plate 25 extends along the
left-hand arm 21. The side plate 25 is rotatably supported on the
left-hand arm 21. The side plate 25 has a first portion 25b and a
second portion 25c which are connected to each other and which are
perpendicular to each other. The portion 25b of the side plate 25
is parallel to the left-hand arm 21. The portion 25b of the side
plate 25 has a rectangular window 25a. A bearing 26A having a
sleeve portion is attached to the left-hand arm 21 by screws.
During the attachment of the bearing 26A to the left-hand arm 21,
the screws are accessed via the rectangular window 25a. The
left-hand shaft 15A is rotatably supported by the bearing 26A.
Similarly, a bearing 26B having a sleeve portion is attached to the
right-hand arm 22 by screws. The right-hand shaft 15B is rotatably
supported by the bearing 26B.
[0068] The first support member 20 is made of an
electrically-conductive metal plate. The first support member 20 is
formed by press molding. The bearings 26A and 26B are composed of
electrically-conductive members.
[0069] The first rotary mechanism 30 includes a motor 31, a
small-diameter gear 32, a large-diameter gear 33, a worm 34, and a
wheel gear 35. A body of the motor 31 is attached to the portion
25c of the side plate 25. The small-diameter gear 32 is fixedly
mounted on an output shaft of the motor 31. The large-diameter gear
33 meshes with the small-diameter gear 32. The worm 34 is fixed to
the large-diameter gear 33. The worm 34 and the large-diameter gear
33 are rotatably supported on the side plate 25. The wheel gear 35
meshes with the worm 34. The wheel gear 35 is fixedly mounted on
the left-hand shaft 15A. The wheel gear 35 has a circular shape
from which an arcuate portion is omitted. Accordingly, the teeth of
the wheel gear 35 extend along only a part of a circumference. As
will be explained later, a flexible cable is passed through a
region formed by the omission of the arcuate portion from the wheel
gear 35. This design enables the apparatus 1 to be compact.
[0070] The second support member 40 is a fixed frame having a pair
of left-hand and right-hand side walls 40a and 40b, and a back wall
40c. The left-hand and right-hand side walls 40a and 40b are
connected by the back wall 40c. The left-hand and right-hand side
walls 40a and 40b are perpendicular to the back wall 40c. The
second support member (the frame) 40 has a U shape in a plan view,
and has an L shape in a side view. The second support member (the
frame) 40 is made of a metal plate, and is formed by press molding.
The second support member (the frame) 40 is sufficiently rigid. A
bearing 41 for receiving the shaft 24 is provided on a central area
of the back wall 40c. The bearing 41 is composed of
electrically-conductive members. The second rotary mechanism 50 is
provided on the second support member (the frame) 40. The second
rotary mechanism 50 extends near the bearing 41.
[0071] The bearings 26A, 26B, and 41 are composed of
electrically-conductive members. Accordingly, the body of the
optical transmitting and receiving unit 10, the first support
member 20, and the second support member 40 are electrically
connected via the bearings 26A, 26B, and 41. This design prevents
static electricity from building up in the apparatus 1.
[0072] The second rotary mechanism 50 includes a swing plate 52, a
motor 53, a small-diameter gear 54, a large-diameter gear 55, a
worm 56, and a wheel gear 57. The swing plate 52 is connected to
the back wall 40c of the second support member 40 by a pin 51. A
body of the motor 53 is attached to the swing plate 52. The
small-diameter gear 54 is fixedly mounted on an output shaft of the
motor 53. The large-diameter gear 55 meshes with the small-diameter
gear 54. The worm 56 is fixed to the large-diameter gear 55. The
worm 56 and the large-diameter gear 55 are rotatably supported on
the swing plate 52. The wheel gear 57 meshes with the worm 56. The
wheel gear 57 is fixedly mounted on the shaft 24. The wheel gear 57
has a circular shape from which an arcuate portion is omitted.
Accordingly, the teeth of the wheel gear 57 extend along only a
part of a circumference. A flexible cable (not shown) can be placed
in a region formed by the omission of the arcuate portion from the
wheel gear 57.
[0073] A bottom bracket 60 has upward projections 60a which hold
the second support member 40. A first printed circuit board 61 is
attached to the second support member 40. A second printed circuit
board 62 is supported on the bottom bracket 60. A third printed
circuit board 63 is supported on the bottom bracket 60 or the
second support member 40. The third printed circuit board 63 may be
mounted on the second printed circuit board 62. The first printed
circuit board 61 extends horizontally. Also, the second printed
circuit board 62 extends horizontally. The first and second printed
circuit boards 61 and 62 are parallel to each other. This
arrangement provides a small height of the apparatus 1. The third
printed circuit board 63 is perpendicular to the first and second
printed circuit boards 61 and 62.
[0074] As shown in FIG. 5, the longitudinal line (the lengthwise
line) passing through the center of the light transmitting lens 12
is offset from the longitudinal line (the lengthwise line) passing
through the center of the light receiving lens 13 by a
predetermined distance ".delta." in a direction away from the motor
31. The longitudinal line passing through the center of the light
receiving lens 13 coincides with the axis of the shaft 24 as viewed
from above. The left-hand shaft 15A is connected via the bearing
26A to the left-hand arm 21 of the first support member 20. The
right-hand shaft 15B is connected via the bearing 26B to the
right-hand arm 22 of the first support member 20. The shaft 24 is
connected via the bearing 41 to the second support member 40.
[0075] As shown in FIG. 6, the first printed circuit board 61
extends above the second printed circuit board 62. The second
printed circuit board 62 extends above the bottom bracket 60. The
first and second printed circuit boards 61 and 62, and the bottom
bracket 60 are parallel to each other. The third printed circuit
board 63 is perpendicular to the first and second printed circuit
boards 61 and 62. The second support member 40 is attached to the
bottom bracket 60 via the upward projections 60a. The first support
member 20 is connected to the second support member 40 on a
cantilever basis. The side plate 25 is rotatably connected to the
left-hand arm 21 via a pin 36. The side plate 25 supports the motor
31, the small-diameter gear 32 (not shown in FIG. 6). the
large-diameter gear 33, and the worm 34 which are the parts of the
first rotary mechanism 30.
[0076] With reference to FIG. 7, a pressing mechanism 71 urges the
worm 34 into mesh with the wheel gear 35. The pressing mechanism 71
includes the side plate 25, the left-hand arm 21, and a spring 72.
The side plate 25 can rotate relative to the left-hand arm 21 about
the pin 36. The spring 72 is connected between the left-hand arm 21
and the portion 25b of the side plate 25. The spring 72 urges the
side plate 25 relative to the left-hand arm 21 in a
counterclockwise direction. The bearing 26A is accommodated in the
rectangular window 25a in the side plate 25. The bearing 26A is
similar in shape to the rectangular window 25a. The rectangular
window 25a has dimensions such that when the bearing 26A is
centered at the rectangular window 25a, the edges of the walls of
the side plate 25 which define the rectangular window 25a are
spaced from the bearing 26A by a predetermined uniform gap "t".
Accordingly, the side plate 25 can move from its central position
in upward and downward directions by a distance corresponding to
the predetermined gap "t".
[0077] As previously-indicated, the wheel gear 35 is fixedly
mounted on the left-hand shaft 15A. The worm 34 is supported on the
side plate 25. The spring 72 urges the side plate 25 in the
counterclockwise direction, thereby pressing the worm 34 against
the wheel gear 35 along an oblique direction {circle over (1)}.
Thus, the worm 34 is pressed against the wheel gear 35 in both an
axial direction and a radial direction, and a backlash hardly
occurs between the worm 34 and the wheel gear 35. The worm 34 is
slidably mounted on a shaft 34a fixed to the side plate 25. A
compression spring 73 urges the worm 34 axially relative to the
shaft 34a. Accordingly, a backlash hardly occurs between the worm
34 and the wheel gear 35 even when the direction of rotation of the
worm 34 changes. Thus, it is possible to provide a good response of
rotational control of the left-hand shaft 15A and a good
reliability of the apparatus 1. The worm 34 can be stopped by a
snap ring 34b mounted on the shaft 34a.
[0078] With reference to FIGS. 8 and 9, the second support member
40 is provided with a pressing mechanism 75 distant from the shaft
24. The pressing mechanism 75 urges the worm 56 into mesh with the
wheel gear 57 which is fixed to the shaft 24. The pressing
mechanism 75 includes the pin 51, the swing plate 52, and a spring
76. The swing plate 52 supports the motor 53, the small-diameter
gear 54, the large-diameter gear 55, and the worm 56 which are the
parts of the second rotary mechanism 50. The swing plate 52 can
rotate relative to the second support member 40 in either a
clockwise direction or a counterclockwise direction about the pin
51. The spring 76 is connected between the swing plate 52 and the
second support member 40. The spring 76 urges the swing plate 52
relative to the second support member 40 in a clockwise direction
{circle over (2)}, thereby pressing the worm 56 against the wheel
gear 57 along an oblique direction {circle over (3)}. Accordingly,
a backlash hardly occurs between the worm 56 and the wheel gear 57.
The worm 56 is slidably mounted on a shaft 56a fixed to the swing
plate 52. A compression spring (not shown) urges the worm 56
axially relative to the shaft 56a. Accordingly, a backlash hardly
occurs between the worm 56 and the wheel gear 57 even when the
direction of rotation of the worm 56 changes. Thus, it is possible
to provide a good response of rotational control of the shaft 24
and a good reliability of the apparatus 1.
[0079] As shown in FIG. 10, the light transmitting and receiving
unit 10 includes a body or a block 16. The light transmitting lens
12 and the light receiving lens 13 are attached to an upper portion
of the block 16. The photosensitive element 14 is attached to a
lower potion of the block 16 via a middle plate 17 forming a
printed circuit board. The light emitting element 11 and a
light-reception-side circuit 19 are attached to the lower portion
of the block 16 via a bottom plate 18. The light transmitting lens
12 and the light receiving lens 13 are arranged side by side. The
axis of the light transmitting lens 12 and the axis of the light
receiving lens 13 are parallel to each other. Accordingly, the
light transmitting lens 12 and the light receiving lens 13 face in
equal directions. The top of the light transmitting lens 12 is
lower than the top of the light receiving lens 13 by a
predetermined height or a predetermined offset "h".
[0080] With reference to FIG. 11, a transmission-side flexible
cable 81 having a flat shape extends along a lower surface of the
left-hand arm 21. The transmission-side flexible cable 81 reaches
the light emitting element 11. The transmission-side flexible cable
81 also extends along the surface of the wheel gear 35 from which
the teeth are omitted. In other words, the transmission-side
flexible cable 81 passes through a region formed by the omission of
the arcuate portion from the wheel gear 35. The transmission-side
flexible cable 81 may extend along a course bypassing the surface
of the wheel gear 35 from which the teeth are omitted. A
reception-side flexible cable 82 having a flat shape extends along
an upper surface of the right-hand arm 22. The reception-side
flexible cable 82 leads from the photosensitive element 14 or the
light-reception-side circuit 19 (see FIG. 10). Accordingly, the
transmission-side flexible cable 81 and the reception-side flexible
cable 82 are separate from each other by a sufficient distance. The
transmission-side flexible cable 81 and the reception-side flexible
cable 82 include, for example, flexible printed circuits
(FPC's).
[0081] Operation of the optical transmitting and receiving
apparatus 1 will be explained hereinafter. The light transmitting
and receiving unit 10 is rotated by the first rotary mechanism 30
about the axes of the shafts 15A and 15B. FIG. 12 shows conditions
in which the light transmitting lens 12 and the light receiving
lens 13 face directly upward. Under the conditions in FIG. 12,
light outputted from the light emitting element 11 travels to the
light transmitting lens 12. The light passes through the light
transmitting lens 12, being converted thereby into a parallel light
beam. The parallel light beam travels from the light emitting lens
12 in a directly upward direction as an outgoing light beam. Under
the conditions in FIG. 12, incoming light which enters the light
receiving lens 13 along a directly downward direction is
concentrated thereby on the photosensitive element 14.
[0082] FIG. 13 shows conditions which occur when the light
transmitting and receiving unit 10 is rotated counterclockwise
about the axes of the shafts 15A and 15B from the position in FIG.
12 by an angle ".theta.". FIG. 14 shows conditions which occur when
the light transmitting and receiving unit 10 is rotated clockwise
about the axes of the shafts 15A and 15B from the position in FIG.
12 by an angle ".theta.". The angle ".theta." in each of FIGS. 13
and 14 can be arbitrarily varied by the first rotary mechanism 30
in response to an output signal of a controller (not shown).
[0083] As shown in FIG. 15, the light transmitting and receiving
unit 10 can be rotated about the axes of the shafts 15A and 15B in
an angular range between +.theta. and -.theta.. This rotation of
the light transmitting and receiving unit 10 is implemented by the
first rotary mechanism 30. The light transmitting and receiving
unit 10 can be rotated about the axis of the shaft 24 in an angular
range between +.alpha. and -.alpha.. This rotation of the light
transmitting and receiving unit 10 is implemented by the second
rotary mechanism 50. Accordingly, the light transmitting and
receiving unit 10 can face in any direction within at least a part
of a spherical range. Thus, the light transmitting and receiving
unit 10 is enabled to accurately follow a moving communication
opposite party.
[0084] It is preferable that as shown in FIG. 17, the center of the
light transmitting lens 12 is offset from the center of the light
receiving lens 13 by a predetermined distance ".delta." along a
widthwise direction of the light transmitting and receiving unit 10
(a widthwise direction of the apparatus 1). Since the light
receiving lens 13 is greater in diameter than the light
transmitting lens 12, the offset arrangement provides a large free
space at one side of the light transmitting lens 12. The motor 31
is placed into the free space at the side of the light transmitting
lens 12. The center of the light receiving lens 13 coincides with a
point on the axis of the shaft 24 (see FIG. 5) as viewed from
above.
[0085] The offset arrangement of FIG. 17 may be replaced by a
non-offset arrangement in FIG. 16. In the non-offset arrangement of
FIG. 16, the centers of a light emitting lens 120 and a light
receiving lens 130 are on a common lengthwise line which separates
from the axis of a motor 310 (corresponding to the motor 31) by a
distance L1. A moment of inertia, that is, a rotational inertia
(GD.sup.2), related to the motor 310 has a factor of
Wm.multidot.(L1).sup.2 where Wm denotes the weight of the motor
310.
[0086] In the offset arrangement of FIG. 17, a lengthwise line
which passes through the center of the light receiving lens 13
separates from the axis of the motor 31 by a distance L2 smaller
than the distance L1. Accordingly, a moment of inertia (a
rotational inertia) related to the motor 31 is smaller than that
related to the motor 310 when the motors 31 and 310 are equal in
weight. The smaller moment of inertia (the smaller rotational
inertia) provides better response characteristics of the motor
31.
[0087] It is preferable that as shown in FIG. 19, the top of the
light transmitting lens 12 is lower than the top of the light
receiving lens 13 by a predetermined height or a predetermined
offset "h".
[0088] The offset arrangement of FIG. 19 may be replaced by a
non-offset arrangement in FIG. 18. In the non-offset arrangement of
FIG. 18, the top of a light emitting lens 120 and the top of a
light receiving lens 130 are equal in height position. In the
non-offset arrangement of FIG. 18, a smallest virtual circle which
surrounds a block 160 (corresponding to the block 16) and parts
mounted thereon has a diameter D1. In the virtual circle, a large
free space extends below a light emitting element 121
(corresponding to the light emitting element 11).
[0089] The offset arrangement of FIG. 19 uses the large free space
below the light emitting element 121 (see FIG. 18) in providing the
offset between the tops of the light emitting lens 12 and the light
receiving lens 13. In the offset arrangement of FIG. 19, a smallest
virtual circle which surrounds the block 16 and parts mounted
thereon has a diameter D2 smaller than the diameter D1. Thus, the
offset arrangement of FIG. 19 provides a compact structure of the
light emitting and receiving unit 10 and a reduced load on the
motor 31.
[0090] As shown in FIG. 20, the visor 65 extends inward of the
cover 3. The visor 65 includes a first cylinder which surrounds a
light propagation path extending in front of the light transmitting
lens 12. Also, the visor 65 includes a second cylinder which
surrounds a light propagation path extending in front of the light
receiving lens 13. Furthermore, the visor 65 includes a tall
partition wall 66 which forms a common portion of the first and
second cylinders. Thus, the partition wall 66 connects the first
and second cylinders. The partition wall 66 separates the two light
propagation paths from each other. The visor 65 prevents outgoing
light, which passes through the light transmitting lens 12, from
entering the light receiving lens 13. The first cylinder, the
second cylinder, and the partition wall 66 of the visor 65 are
integral with each other.
[0091] It should be noted that the first and second cylinders in
the visor 65 may be separate members respectively.
[0092] With reference to FIG. 21, in some cases, a portion of
outgoing light which has passed through the light transmitting lens
12 is reflected at the inner surfaces of the cover 3 toward the
light receiving lens 13 as denoted by the arrow {circle over (4)}.
The partition wall 66 of the visor 65 blocks such unwanted light
{circle over (4)}. In the absence of the partition wall 66, a
portion of outgoing light which had passed through an edge of the
light transmitting lens 12 might be reflected at the inner surfaces
of the cover 3 toward the light receiving lens 13 as denoted by the
arrow {circle over (5)}. The partition wall 66 of the visor 65
blocks such unwanted light {circle over (5)}. In addition, the
visor 65 periodically reflects disturbance-causing light, thereby
attenuating the disturbance-causing light.
[0093] As previously explained, the visor 65 prevents outgoing
light, which passes through the light transmitting lens 12, from
entering the light receiving lens 13. Therefore, the visor 65
prevents wrong operation of the apparatus 1 which would be caused
by such unwanted entrance of outgoing light into the light
receiving lens 13.
[0094] The visor 65 has two open ends corresponding to the light
transmitting lens 12 and the light receiving lens 13 respectively.
It is preferable that the curvature radius "r" (in FIG. 20) of the
transmission-side open end of the visor 65 agrees with that of the
inner surfaces of the cover 3.
[0095] As shown in FIG. 24, the transmission-side flexible cable 81
extends along the left-hand arm 21 while the reception-side
flexible cable 82 extends along the right-hand arm 22. The
transmission-side flexible cable 81 is distant from the axis of the
shaft 24 by a value L4. The reception-side flexible cable 82 is
distant from the axis of the shaft 24 by a value L5. Adjustment of
the distances L4 and L5 provides a balanced rotation moment related
to the rotation of the combination of the parts about the axis of
the shaft 24.
[0096] As shown in FIG. 25, the reception-side flexible cable 82
includes a non-shield-type substrate having a base film 83. An
adhesive layer 84, a pattern-side conductive layer 85, an adhesive
layer 86, and a cover film 87 are successively laminated on the
base film 83. Such a non-shield-type substrate is light in weight,
thin, inexpensive, and remarkably flexible. The transmission-side
flexible cable 81 is similar in structure to the reception-side
flexible cable 82. Since the transmission-side flexible cable 81
and the reception-side flexible cable 82 are distant from each
other, it is possible to prevent crosstalk between the cables 81
and 82.
[0097] The cable arrangement of FIG. 24 may be replaced by a cable
arrangement of FIG. 22 which includes a transmission-reception
flexible cable 820 instead of the transmission-side flexible cable
81 and the reception-side flexible cable 82. In the cable
arrangement of FIG. 22, the transmission-reception flexible cable
820 extends along a right-hand arm 220 corresponding to the
right-hand arm 22.
[0098] As shown in FIG. 23, the transmission-reception flexible
cable 820 includes a shield-type substrate having a base film 821.
An adhesive layer 822, a pattern-side conductive layer 823, an
adhesive layer 824, and a cover film 825 are successively laminated
on an upper surface of the base film 821. An adhesive layer 826, a
shield-pattern-side conductive layer 827, an adhesive layer 828,
and a cover film 829 are successively laminated on a lower surface
of the base film 821.
[0099] In the cable arrangement of FIG. 22, a weight 830 may be
attached to a left-hand arm 210 (corresponding to the left-hand arm
21) to provide a good balance with respect to the rotation of a
combination of parts about the axis of a shaft 240 (corresponding
to the shaft 24).
[0100] The optical transmitting and receiving apparatus 1 has the
following advantages. The optical axis of the apparatus 1 can be
varied at a high speed. The apparatus 1 can accurately face an
apparatus of a communication opposite party. The apparatus 1 can
quickly follow movement of the apparatus of the communication
opposite party. Since the transmission-side flexible cable 81 and
the reception-side flexible cable 82 are located at a left-hand
side and a right-hand side of the apparatus 1 respectively, it is
possible to easily provide a stable apparatus weight balance. In
addition, it is possible to prevent crosstalk between a
transmission signal and reception signal on the cables 81 and 82.
Since the bearings 26A, 26B, and 41 are composed of
electrically-conductive members, static electricity can be
prevented from building up in the apparatus 1. Since the light
transmission side and the light reception side of the apparatus 1
are optically isolated by the visor 65, outgoing light emitted from
the light transmission side can be prevented from entering the
light receiving side. In addition, the visor 65 periodically
reflects disturbance-causing light, thereby attenuating the
disturbance-causing light.
* * * * *