U.S. patent application number 12/461226 was filed with the patent office on 2009-12-03 for illuminative light communication system, lighting device and illuminative light source.
This patent application is currently assigned to Nakagawa Laboratories, Inc.. Invention is credited to Shinichiro Haruyama, Toshihiko Komine, Masao Nakagawa.
Application Number | 20090297156 12/461226 |
Document ID | / |
Family ID | 32180882 |
Filed Date | 2009-12-03 |
United States Patent
Application |
20090297156 |
Kind Code |
A1 |
Nakagawa; Masao ; et
al. |
December 3, 2009 |
Illuminative light communication system, lighting device and
illuminative light source
Abstract
Information received from a wired network terminal on the wall
face, or the like, is delivered as a light signal from a light
transmitting/receiving section of a light communication unit. A
lighting fixture is provided with a light transmitting/receiving
section where light is received from the light communication unit
in order to acquire information, and a light emitting element emits
illumination light modulated according to that information. A
terminal can acquire the information by receiving the illumination
light at a light transmitting/receiving section. Since
communication is performed from the light communication unit to the
terminal by irradiating light into the space, a convenient
illumination light communication system requiring no communication
cable or laying work of optical fibers can be constructed.
Inventors: |
Nakagawa; Masao; (Kanagawa,
JP) ; Komine; Toshihiko; (Shizuoka, JP) ;
Haruyama; Shinichiro; (Kanagawa, JP) |
Correspondence
Address: |
RADER FISHMAN & GRAUER PLLC
LION BUILDING, 1233 20TH STREET N.W., SUITE 501
WASHINGTON
DC
20036
US
|
Assignee: |
Nakagawa Laboratories, Inc.
Tokyo
JP
|
Family ID: |
32180882 |
Appl. No.: |
12/461226 |
Filed: |
August 5, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10532250 |
Sep 29, 2005 |
7583901 |
|
|
PCT/JP2003/013539 |
Oct 23, 2003 |
|
|
|
12461226 |
|
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Current U.S.
Class: |
398/130 |
Current CPC
Class: |
F21K 9/65 20160801; F21V
33/0052 20130101; H05B 47/195 20200101; H05B 47/185 20200101; H05B
47/19 20200101; H04B 10/1141 20130101; H04B 2203/5412 20130101;
H04B 3/54 20130101; H01L 2924/3025 20130101; F21K 9/20 20160801;
H04B 2203/5458 20130101; H01L 2224/48091 20130101; H04B 10/1149
20130101; H01L 2224/48247 20130101; H04B 10/116 20130101; G09F 9/33
20130101; H01L 25/0753 20130101; F21Y 2115/10 20160801; H01L
2224/48091 20130101; H01L 2924/00014 20130101; H01L 2224/48091
20130101; H01L 2924/00 20130101; H01L 2924/3025 20130101; H01L
2924/00 20130101 |
Class at
Publication: |
398/130 |
International
Class: |
H04B 10/10 20060101
H04B010/10 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 24, 2002 |
JP |
2002-309557 |
Dec 4, 2002 |
JP |
2002-352075 |
Jan 10, 2003 |
JP |
2003-004560 |
Feb 17, 2003 |
JP |
2003-037746 |
Mar 14, 2003 |
JP |
2003-070673 |
Mar 25, 2003 |
JP |
2003-082278 |
Mar 26, 2003 |
JP |
2003-084819 |
Jun 6, 2003 |
JP |
2003-161859 |
Jun 23, 2003 |
JP |
2003-177816 |
Sep 16, 2003 |
JP |
2003-323052 |
Claims
1. An illuminative light communication system, comprising: a
plurality of lighting units that emits light for lighting; and an
optical communication unit that optically transmits data through
the air to the lighting units; wherein the lighting units receive
light from the optical communication unit, thereby capturing data,
and modulate emitted light in accordance with the data.
2. An illuminative light communication system, comprising: a
plurality of lighting units that emits light for lighting; and an
optical communication unit that optically transmits data through
the air to one or more of the lighting units; wherein the one or
more of the lighting units receive light from the optical
communication unit, thereby capturing data, and optically transmit
the data through the air to another lighting unit; and each
lighting unit modulates emitted light in accordance with the data
received from the optical communication unit or another lighting
unit and transmits the data via the modulated, emitted light.
3. The illuminative light communication system according to either
claim 1 or claim 2, wherein the plurality of lighting units is an
indoor illumination lamp.
4. The illuminative light communication system according to claim
2, wherein the plurality of lighting units is a street lamp.
5. The illuminative light communication system according to either
claim 1 or claim 2, wherein the plurality of lighting units allows
optical bidirectional communication through the air with the
optical communication unit or another lighting unit.
6. The illuminative light communication system according to claim
5, wherein the plurality of lighting units comprises a light
receiving unit that receives light modulated in accordance with
data emitted from a terminal device, which receives emitted light
and thereby receives data, and allows optical bidirectional
communication between the terminal device and the plurality of
lighting units.
7. The illuminative light communication system according to either
claim 1 or claim 2, wherein the plurality of lighting units uses a
semiconductor light emitting device as an illuminative light
source.
8. A lighting device, comprising: one or a plurality of
illuminative light emitting units that emits light for lighting; an
optical transmitting and receiving unit for optically communicating
through the air with a light emitting unit provided in a device;
and a control unit that controls the illuminative light emitting
unit in accordance with data received by the light transmitting and
receiving unit, so as to modulate light emitted from the
illuminative light emitting unit in accordance with the data,
thereby transmitting the data.
9. The lighting device according to claim 8, wherein the optical
transmitting and receiving unit is deployed in a plurality of
positions in different communication directions; and the control
unit controls so that data received by a certain light transmitting
and receiving unit can be optically transmitted through the air
from another light transmitting and receiving unit to the
device.
10. The lighting device according to claim 8, wherein the
illuminative light emitting unit lights indoors.
11. The lighting device according to claim 8, wherein the
illuminative light emitting unit lights the road.
12. The lighting device according to claim 8, wherein the optical
transmitting and receiving unit allows bidirectional optical
communication through the air with the device.
13. The lighting device according to claim 12, further comprising a
light receiving unit that receives light modulated in accordance
with data emitted from a terminal device, which receives light
emitted from the light emitting unit, thereby receiving data;
wherein bidirectional communication with the terminal device is
carried out via light.
14. The lighting device according to claim 8, wherein the
illuminative light emitting unit comprises one or a plurality of
semiconductor light emitting devices as an illuminative light
source.
15. An illuminative light source, comprising: one or a plurality of
illuminative light emitting devices that emits light for lighting;
an optical transmitting and receiving unit for optically
communicating through the air with a light emitting unit provided
in another lighting unit; and a control unit that controls the
illuminative light emitting device in accordance with data received
by the optical transmitting and receiving unit, so as to modulate
light emitted by the illuminative light emitting device in
accordance with the data, thereby transmitting the data.
16. The illuminative light source according to claim 15, wherein
the optical transmitting and receiving unit is deployed in a
plurality of positions in different communication directions; and
the control unit controls so that data received by a certain light
transmitting and receiving unit can be optically transmitted
through the air from another light transmitting and receiving unit
to the another device.
17. The illuminative light source according to claim 15, wherein
the optical transmitting and receiving unit is structured to be
capable of changing an optical transmission and a reception
direction.
18. The illuminative light source according to claim 15, wherein
the optical transmitting and receiving unit is deployed in plural;
one is used, in the case of the plurality of illuminative light
emitting devices being arranged, to allow optical communication
through the air with an adjacent illuminative light source, while
the other is used to allow optical communication through the air
with another illuminative light source provided in another lighting
unit.
19. The illuminative light source according to claim 15, wherein
the optical transmitting and receiving unit carries out
bidirectional optical communication through the air with the
another lighting unit.
20. The illuminative light source according to claim 19, further
comprising a light receiving unit that receives light modulated in
accordance with data emitted from a terminal device, which receives
light emitted from the light emitting unit, thereby receiving data;
wherein bidirectional optical communication is carried out through
the air with the terminal device.
21. The illuminative light source according to claim 15, wherein
the illuminative light emitting device is one or a plurality of
semiconductor light emitting devices.
Description
CROSS-REFERENCES TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S patent application
Ser. No. 10/532,250 filed Oct. 23, 2003, as International
Application No. PCT/JP03/013539, now pending, the contents of
which, including specification, claims and drawings, are
incorporated herein by reference in their entirety. This
application claims priority from Japanese Patent Application Ser.
No. 2003-084819 filed Mar. 26, 2003, the contents of which are
incorporated herein by reference in their entireties.
BACKGROUND OF THE INVENTION
[0002] The present invention aims to provide an illuminative light
communication system that does not require electrical work for
providing a cable or an optical fiber, and prevents problems such
as restriction on bandwidths, radio wave radiation, and
superimposition of noise from developing, which is different than
power line communication, and a lighting device and an illuminative
light source used for such illuminative light communication
system.
[0003] According to such objective, an illuminative light
communication system that carries out communication using
illuminative light includes multiple lighting units that emit light
for lighting and an optical communication unit that optically
transmits data through the air to the lighting units. The lighting
units receive light from the optical communication unit, thereby
capturing data, and modulate emitted light in accordance with the
data. According to such objective, an illuminative light
communication system includes multiple lighting units that emit
light for lighting; and an optical communication unit that
optically transmits data through the air to one or more of the
lighting units. The one or more of the lighting units receive light
from the optical communication unit, thereby capturing data, and
optically transmit the data through the air to another lighting
unit. Each lighting unit modulates emitted light in accordance with
the data received from the optical communication unit or another
lighting unit and transmits the data via the modulated, emitted
light.
[0004] With such structure, data to be transmitted to the lighting
unit that allows communication through modulating illuminative
light is transmitted through the air from the optical communication
unit or another peripheral lighting unit. When using an optical
fiber for optical communication, it is necessary to provide the
optical fiber. On the other hand, it is unnecessary when carrying
out optical communication via the air. As a result, the
illuminative light communication system can be constructed very
easily. In addition, different than power line communication,
problems such as restriction on bandwidths and radio wave radiation
do not develop.
[0005] Note that the plurality of lighting units allows optical
bi-directional communication through the air with the optical
communication unit or another lighting unit. In addition, since the
plurality of lighting units includes a light receiving unit that
receives light modulated in accordance with data emitted from a
terminal device, which receives emitted light and thereby receives
data, optical bidirectional communication between the terminal
device and the plurality of lighting units is possible.
Furthermore, the plurality of lighting units uses a semiconductor
light emitting device such as an LED as an illuminative light
source. The plurality of lighting units can be an indoor
illumination lamp or a street lamp.
[0006] A lighting device used for such aforementioned illuminative
light communication system includes one or multiple illuminative
light emitting units that emits light for lighting, an optical
transmitting/receiving unit for optically communicating through the
air with a light emitting unit provided in a device, and a control
unit that controls the illuminative light emitting unit in
accordance with data received by the light transmitting/receiving
unit, so as to modulate light emitted from the illuminative light
emitting unit in accordance with the data, thereby transmitting the
data.
[0007] With such structure, since there is no need to provide a
cable or an optical fiber as described above, an illuminative light
communication system can be constructed through simple electrical
work such as replacement of an existing lighting device with a
lighting device, according to the present invention.
[0008] Note that the optical transmitting/receiving unit is
deployed in multiple positions in different communication
directions, and data received by a certain light
transmitting/receiving unit can be optically transmitted through
the air from another light transmitting/receiving unit to the
device. As a result, the lighting devices can be deployed freely,
and data transmission is possible regardless of the positions of
the lighting devices. In addition, the light transmitting/receiving
unit allows bi-directional optical communication through the air
with another device. Furthermore, since the plurality of lighting
units includes a light receiving unit that receives light modulated
in accordance with data emitted from a terminal device, which
receives emitted light and thereby receives data, optical
bidirectional communication among the terminal device and the
plurality of lighting units is possible. The plurality of
illuminative light emitting units uses a semiconductor light
emitting device such as an LED as an illuminative light source. The
plurality of lighting units can be an indoor illumination lamp or a
street lamp.
[0009] Furthermore, an illuminative light source includes one or
multiple illuminative light emitting devices that emits light for
lighting, an optical transmitting/receiving unit for optically
communicating through the air with a light emitting unit provided
in another lighting unit, and a control unit that controls the
illuminative light emitting device in accordance with data received
by the optical transmitting/receiving unit, so as to modulate light
emitted by the illuminative light emitting device in accordance
with the data, thereby transmitting the data.
[0010] In this manner, by providing the optical
transmitting/receiving unit and the control unit in the
illuminative light source, construction of an illuminative light
communication system using the existing lighting device, merely
with simple electrical work such as replacement of a fluorescent
lamp or an electric bulb with an illuminative light source
according to the present invention becomes possible.
[0011] The optical transmitting/receiving unit is deployed in
multiple positions in different communication directions. Data
received by a certain light transmitting/receiving unit can be
optically transmitted through the air from another light
transmitting/receiving unit to another device. In addition, by
structuring the optical transmitting/receiving unit so as to be
able to change an optical transmission/reception direction,
deployment of them on arbitrarily positioned lighting devices
becomes possible. Furthermore, as with a lighting device using a
fluorescent lamp, the optical transmitting/receiving unit is
deployed in plural; one is used, in the case of the plurality of
illuminative light emitting devices being arranged, to allow
optical communication through the air with an adjacent illuminative
light source, while the other is used to allow optical
communication through the air with another illuminative light
source provided in another lighting unit.
[0012] With such an illuminative light source, the optical
transmitting/receiving unit can be structured allowing
bidirectional optical communication through the air with another
lighting unit. Furthermore, since the plurality of lighting units
includes a light receiving unit that receives light modulated in
accordance with data emitted from a terminal device, which receives
emitted light and thereby receives data, optical bidirectional
communication among the terminal device and the plurality of
lighting units is possible. The illuminative light emitting device
may be one or multiple semiconductor light emitting devices such as
LEDs. Note that the illuminative light source may be an indoor
illumination lamp or an outdoor street lamp.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is an explanatory diagram of an illuminative light
communication system, according to a first embodiment of the
present invention;
[0014] FIG. 2 is an explanatory diagram of an illuminative light
communication system, according to a second embodiment of the
present invention;
[0015] FIG. 3 is an aerial view of an exemplary lighting element in
the illuminative light communication system, according to the
second embodiment of the present invention;
[0016] FIGS. 4A and 4B each is an explanatory diagram of a first
modified example of the illuminative light communication device,
according to the second embodiment of the present invention; FIG.
4A is a cross-sectional view; and FIG. 4B is a perspective
view;
[0017] FIG. 5 is an explanatory diagram of a second modified
example of the illuminative light communication system, according
to the second embodiment of the present invention;
[0018] FIG. 6 is an explanatory diagram of a third modified example
of the illuminative light communication system, according to the
second embodiment of the present invention;
[0019] FIG. 7 is an explanatory diagram of an illuminative light
communication system, according to a third embodiment of the
present invention;
[0020] FIG. 8 is another explanatory diagram of the illuminative
light communication system, according to the third embodiment of
the present invention;
[0021] FIG. 9 is an explanatory diagram describing an exemplary
illuminative light source in the illuminative light communication
system, according to the third embodiment of the present
invention;
[0022] FIG. 10 is an explanatory diagram of an illuminative light
communication system, according to a fourth embodiment of the
present invention;
[0023] FIG. 11 is an explanatory diagram describing an exemplary
illuminative light source in the illuminative light communication
system, according to the fourth embodiment of the present
invention; and
[0024] FIG. 12 is an explanatory diagram of an illuminative light
communication system, according to a fifth embodiment of the
present invention.
BEST MODE FOR CARRYING OUT THE INVENTION
[0025] Lighting elements are provided on a ceiling, or a pole is
provided for illuminating light from above so as to prevent shadows
across a certain area. There is an advantage for illuminative light
communication in that high quality communication is possible
because shadowing does not develop and high illuminative electric
power is available.
[0026] Meanwhile, since lighting elements are provided in high
places such as the ceiling as described above, there is a problem
that it is difficult to carry out electrical work. For example, in
the case of the aforementioned illuminative light communication,
data to be transmitted must be sent to the lighting elements
through illuminative light communication. A method of providing a
cable or an optical fiber for a network may be considered as a
method for transmitting data to lighting elements, for example.
However, since new electrical work is necessary for providing a
cable or an optical fiber, usage of illuminative light
communication is not easy and is costly.
[0027] As with the present invention, a method of superimposing a
signal on an electric wire for lighting and transmitting the
resulting data to lighting elements, for example, has been
considered as a method not requiring provision of additional cables
or optical fibers. However, in the case of transmitting data by
superimposing a signal on an electric wire, undesired radio
emission may often develop or wireless communication may be
interrupted when the frequency of the signal is high. In addition,
there is another problem in that signals are easily influenced by
motor noise and inverter noise.
[0028] As described above, there have been no preferred means for
transmitting data to lighting elements for illuminative light
communication, which has been an obstacle to illuminative light
communication. The present invention provides a preferred means for
transmitting data to each lighting element.
[0029] FIG. 1 is an explanatory diagram of an illuminative light
communication system, according to a first embodiment of the
present invention. In the drawing, 501 denotes an optical
communication device, 502 denotes lighting elements, 503 denotes a
terminal device, 511, 522, and 531 denote light
transmitting/receiving units, 512 denotes a communication cable,
521 denotes light emitting devices, and 523 denotes light reception
devices. In the example shown in FIG. 1, an illuminative light
communication system is structured using lighting elements provided
for indoor lighting.
[0030] The optical communication device 501, which transmits to the
lighting elements 502 data that is to be sent by them through
illuminative light communication, is provided indoors. The optical
communication device 501 is connected to the network, and
transmits/receives data via the network. The network is a wired
network, which is provided in offices, schools, plants, and homes,
and is configured from an optical fiber, a coaxial cable, or a
stranded wire, many of which are connected to an external telephone
network or the Internet. A terminal of such network is often
provided in a wall as shown in FIG. 1. In such case, electrical
connection between the wall surface terminal and the optical
communication device 501 is made by the communication cable
512.
[0031] The optical communication device 501 allows communication
via the network as described above, and has the light
transmitting/receiving unit 511 allowing optical communication
among the lighting elements 502 through the air. According to the
present invention, since optical communication is carried out
through the air, an optical fiber is unnecessary. Needless to say,
it is unnecessary to extend the communication cable 512 to the
respective lighting elements 502. Since the lighting elements 502
are provided at a high position such as the ceiling, the optical
communication device 501 may be provided at a lower position where
the lighting elements 502 carrying out communication cannot be
blinded.
[0032] The light transmitting/receiving unit 511 includes a light
emitting device and a light reception device, emits modulated light
through control of the light emitting device to modulate in
accordance with data, and transmits data to the lighting elements
502. In this example, it is desirable that lights emitted from the
light emitting device may be received by the multiple lighting
elements 502. Therefore, light with poor directivity is preferable.
Alternatively, it is possible to output to the respective lighting
elements 502 emitted lights with high directivity, which allows
identification of each lighting element 502.
[0033] The light reception device receives light emitted from the
light transmitting/receiving units 522 of the lighting elements
502, thereby receiving data transmitted from the lighting elements
502. Note that since illuminative light emitted from the lighting
elements 502 is received, it is necessary to separate and capture
data from the light emitted from the light transmitting/receiving
units 522 of the lighting element 502. When it is unnecessary to
receive data from the lighting elements 502, the light reception
device is unnecessary.
[0034] With such structure, the optical communication device 501
allows communication via the wired communication cable 512 and
functions as a gateway, which carries out conversion for optical
communication. In addition, through communication with multiple
lighting elements 502, it also functions as a base station for
wireless (optical) communication. Note that light used by the light
transmitting/receiving unit 511 for communication is not limited to
visible light, and infrared light is also available.
[0035] The lighting elements 502, according to the present
invention, are provided on the ceiling, for example, and
illuminates indoors by light emitted from the light emitting
device. The lighting elements 502 are each provided with light
transmitting/receiving units 522 including light emitting devices
and light reception devices. According to this embodiment, optical
communication with the optical communication device 501 through the
air is carried out. The light emitting devices should be formed so
as to allow pinpoint reception of light from the light
transmitting/receiving unit 511 of the optical communication device
501 by providing a lens system, for example. Needless to say,
direction should be appropriately changeable in consideration of
light incident direction. The light emitting devices are provided
for transmitting data to the optical communication device 501 from
the lighting elements 502, and should allow pinpoint transmission
of light to the light transmitting/receiving unit 511 of the
optical communication device 501. For example, when using laser
diodes (LDs), a rectilinear progression characteristic may improve,
and identifiability of the optical communication device 501 may be
improved by coherent light. These light transmitting/receiving
units 522 allow bidirectional data communication among the lighting
elements 502 and the optical communication device 501.
[0036] The lighting elements 502 are each provided with a
controller not shown in the drawing. The light
transmitting/receiving units 522 receive and demodulate light, and
the resulting demodulated data is transmitted to corresponding
controller. The controller controls the light emitting devices 521
to modulate in accordance with received data and emits illuminative
light modulated in accordance with that data. This allows
illuminative light data transmission from the lighting elements 502
to the terminal device 503.
[0037] In the example shown in FIG. 1, the light emitting devices
521 are indicated by o symbols, and the light reception devices 523
indicated by .cndot. symbols are provided therebetween. Since the
light emitting devices 521, which are used for lighting as
described above, emit light modulated in accordance with data,
those having a high-speed response characteristic are available.
For example, semiconductor light emitting devices such as LEDs and
LDs are optimum.
[0038] The light reception devices 523 are used for receiving light
from the terminal device 503. They receive and demodulate modulated
light emitted from the terminal device 503, and the controller can
then capture data transmitted from the terminal device 503. The
captured data may be optically transmitted from the light
transmitting/receiving units 522 to the optical communication
device 501, and then to the network. Those light reception devices
523 allow bidirectional communication among the lighting elements
502 and the terminal device 503. Note that those light reception
devices 523 may receive infrared light, other than visible light.
In addition, a structure such that an antenna is provided instead
of the light reception devices 523 for radio wave data reception
from the terminal device 503 is possible. In the case of a
broadcast system, the light reception devices 523 are
unnecessary.
[0039] The terminal device 503 is a data terminal comprising the
light transmitting/receiving unit 531. The light
transmitting/receiving unit 531 receives and demodulates
illuminative light, thereby capturing data. In addition, the light
transmitting/receiving unit 531 is controlled to emit light
modulated in accordance with data, thereby transmitting data from
the terminal device 503 to the lighting elements 502. The terminal
device 503 may be provided in an arbitrary position as long as it
is illuminated by the lighting elements 502. Accordingly,
communication is possible even if the terminal device 503 is
movable. In addition, since the lighting elements are typically
provided so as to prevent shadows, and illuminative light has large
electric power, high quality and high speed communication is
possible. Furthermore, illuminative light may be used safely
without adversely influencing the human body such as eyes as with
infrared rays.
[0040] In the aforementioned first embodiment, the optical
communication device 501 controls the light transmitting/receiving
unit 511 to emit light, thereby optically transmitting data, which
has been transmitted from the network, through the air. The
respective light transmitting/receiving units 522 of the lighting
elements 502 receive light emitted from the light
transmitting/receiving unit 511 of the optical communication device
501, thereby receiving data. The respective lighting elements 502
then control the light emitting devices 521 to modulate in
accordance with data captured through reception of light by the
light transmitting/receiving units 522, and thereby outputting the
modulated illuminative light. The terminal device 503 receives and
demodulates the modulated illuminative light, and thus the terminal
device 503 can receive data.
[0041] On the other hand, the light transmitting/receiving unit 531
of the terminal device 503 emits light modulated in accordance with
data in the terminal device 503. The light reception devices 523 of
the lighting devices 502 then receive that emitted light, thereby
receiving that data. The light transmitting/receiving units 522 of
the lighting devices 502 then emit light modulated in accordance
with that received data, transmitting the data to the optical
communication device 501. In the optical communication device 501,
the light transmitting/receiving unit 511 receives modulated light
from the lighting elements 502 and converts it to electrical
signals, transmitting the resulting signals to the network. This
allows data transmission from the terminal device 503 to the
network.
[0042] FIG. 2 is an explanatory diagram of an illuminative light
communication device, according to a second embodiment of the
present invention. FIG. 3 is a planar view of an exemplary lighting
element, according to the second embodiment of the present
invention. In the drawings, the same symbols are given to the same
parts as those in FIG. 1, and repetitive descriptions thereof are
thus omitted. 502-1 through 502-4 denote lighting elements, 541
denotes sockets, and 542 denotes rod-shaped illuminative light
sources. The aforementioned first embodiment gives an example where
the lighting elements 502 receive modulated light from the optical
communication device 501, respectively. On the other hand, the
second embodiment shows a case of data transmission among the
lighting elements 502-1 through 502-4. In addition, different from
the example shown in FIG. 1, the light emitting devices 521 are
arranged in the lighting elements 502-1 through 502-4 so as to form
the same shape as typically used strip lights. Note that the
lighting elements 502-1 through 502-4 are identical lighting
elements, which are referred to as lighting elements 502 when they
are not being differentiated.
[0043] In the second embodiment, as shown in FIG. 3, light
transmitting/receiving units 522 are provided on all four sides of
the lighting elements 502, and allow communication among the
lighting elements 502. In addition, only the light
transmitting/receiving units 522 of any one or multiple lighting
elements 502 communicate with the optical communication device 501.
Other lighting elements 502, which do not communicate directly with
the optical communication device 501, transmit/receive data by
communicating with another lighting element 502.
[0044] In the example shown in FIG. 2, the lighting element 502-1
communicates directly with the optical communication device 501.
The lighting elements 502-2 and 502-3 communicate with the lighting
element 502-1 to receive/transmit data from/to the optical
communication device 501. The lighting element 502-4 communicates
with the lighting element 502-2 or 502-3 to receive/transmit data
from/to the optical communication device 501. For example, data
from the optical communication device 501 is transmitted to the
lighting element 502-1, and that transmitted data is then
transmitted to the lighting elements 502-2 and 502-3. The data is
then transmitted from the lighting element 502-2 or 502-3 to the
lighting element 502-4. As a result, the data from the optical
communication device 501 is transmitted to the lighting elements
502-1 through 502-4, and the respective lighting elements 502-1
through 502-4 transmit data via illuminative light to the terminal
device 503. On the other hand, when the lighting element 502-4
receives modulated light from the terminal device 503, the lighting
element 502-4 transmits that data to the lighting element 502-2 or
502-3, the lighting element 502-2 or 502-3 transmits that data to
the lighting element 502-1, the lighting element 502-1 transmits
that data to the optical communication device 501, and the data is
then transmitted to the network.
[0045] The light transmitting/receiving units 522 are used for
optical communication among the respective lighting elements 502
through the air. This allows communication from the optical
communication device 501 to the respective lighting elements 502
without providing a communication cable or an optical fiber. In
addition, with the first embodiment, it can be considered that
light intensity for communication among the optical communication
device 501 and the lighting elements 502 attenuates if the lighting
elements 502 are provided at a distance from the optical
communication device 501. On the other hand, with the second
embodiment, since the respective lighting elements 502 are provided
at almost regular intervals, communication quality does not
decrease due to locations of the lighting elements 502.
Furthermore, since data is transmitted through communication among
the lighting elements 502, even the lighting elements 502 provided
within an area visible from the optical communication device 501
may be used for illuminative light communication, which is possible
by communicating indirectly with the optical communication device
501 through communication with another lighting element 502.
[0046] The light transmitting/receiving units 522 allow
bi-directional communication among the lighting elements 502 and
among the lighting elements 502 and the optical communication
device 501. Note that in the case of unidirectional communication
as with a broadcast system, the light transmitting/receiving units
522 may be constituted by either light emitting devices or light
reception devices, and light emitting devices and light reception
devices of the respective lighting elements 502 for data
communication should be provided facing one another.
[0047] In the second embodiment, the rod illuminative light sources
542 with the same shape as strip lights as shown in FIG. 3 are
used. One or several lines of light emitting devices 521 are
arranged in the rod illuminative light sources 542, and light
reception devices 523 are provided therebetween. To provide a new
lighting element, the shape of illuminative light source is
arbitrary and is determined based on illuminative light source and
design. However, if an existing lighting element is used, it is
desirable that the rod-shaped illuminative light sources 542 with
the same shape as strip lights are used. When the rod illuminative
light sources 542 are inserted into the fluorescent sockets 541,
electric power is supplied to the rod illuminative light sources
542, allowing lighting. In this case, a controller not shown in the
drawing is provided in each of the rod illuminative light sources
542. In addition, the light transmitting/receiving units 522 should
be provided surrounding the existing lighting elements and be
electrically connected to the rod illuminative light sources 542.
As a result, the lighting elements, according to the present
invention, may be provided using existing lighting elements. Use of
existing lighting elements allows illuminative light communication
at lower cost than that for replacement with new lighting
elements.
[0048] Needless to say, the shape of the illuminative light source
is not limited to the same rod shape as strip lights and may have a
circular shape as with circular fluorescent lamps. Alternatively,
an electric bulb-shaped illuminative light source is available, as
described later.
[0049] FIGS. 4A and 4B each is an explanatory diagram of a first
modified example of the illuminative light communication system,
according to the second embodiment of the present invention. In the
example shown in FIG. 2, the lighting elements are provided on the
ceiling. Alternatively, for example, the lighting elements 502 may
be embedded in the ceiling as shown in FIGS. 4A and FIG. 4B. In
such case, as shown in FIGS. 4A and 4B, for example, the light
transmitting/receiving units 522 are provided protruding from the
ceiling, allowing optical communication among the lighting elements
502.
[0050] FIG. 5 is an explanatory diagram of a second modified
example of the illuminative light communication system, according
to the second embodiment of the present invention. In the example
shown in FIG. 5, the lighting elements 502 are also embedded in the
ceiling. When embedding the lighting elements 502 in the ceiling,
there is space under the roof exceeding that needed for embedding
the lighting elements 502. A structure that utilizes this space
under the roof to provide the light transmitting/receiving units
522 under the roof for communication among the lighting elements
502 and among the lighting elements 502 and the optical
communication device 501 is possible.
[0051] FIG. 6 is an explanatory diagram of a third modified example
of the illuminative light communication system, according to the
second embodiment of the present invention. The example shown in
FIG. 6 shows a case of using suspended shades as the lighting
elements 502. In the case of suspended lamps, electric bulbs are
often used as the light sources. According to the present
invention, electric bulb-shaped illuminative light sources are
used. In addition, the light transmitting/receiving units 522 are
provided at the upper part of underneath the shades of the lighting
elements 502. Needless to say, the positions of the light
transmitting/receiving units 522 may be arbitrary as long as
communication with other lighting elements 502 and with the optical
communication device 501 is possible.
[0052] For example, the suspended lighting elements 502 are often
provided over each customer's seat in a store. The structure shown
in FIG. 6 is useful for such application. For example, when opening
an internet cafe, broadband communication may be provided merely
through optical communication among the lighting elements 502 and
among the lighting elements 502 and the optical communication
device 501 without providing cables in the store.
[0053] FIGS. 7 and 8 are explanatory diagrams of an illuminative
light communication system, according to a third embodiment of the
present invention. FIG. 9 is a diagram describing an exemplary
illuminative light source, according to the third embodiment of the
present invention. In the drawing, 551 denotes illuminative light
sources, 552 denotes inter-adjacent light source light
transmitting/receiving units, and 553 denotes inter-lighting
element light transmitting/receiving units. In the aforementioned
example shown in FIG. 3, the light transmitting/receiving units 522
must be provided in addition to the illuminative light sources even
when using the existing lighting elements. The third embodiment
shows an exemplary structure where the illuminative light sources
and the light transmitting/receiving units 522 are integrated.
[0054] In the example shown in FIG. 9, for example, the shape of
the illuminative light sources 551, according to the fifth
embodiment of the present invention, is the same rod shape as strip
lights as with the example shown in FIG. 3. The illuminative light
sources 551 each comprises light emitting devices 521, light
reception devices 523, and a controller not shown in the drawing.
In addition, the inter-adjacent light source light
transmitting/receiving units 552 are provided on the tube and are
used for communication between adjacent illuminative light sources
551 when the illuminative light sources 551 are positioned so as to
provide multiple fluorescent lamps in parallel. Note that assuming
the case of providing three or more of illuminative light sources
551, the inter-adjacent light source light transmitting/receiving
units 552 should be provided on both sides of the tube.
[0055] In addition, the inter-lighting element light
transmitting/receiving units 553 are provided for communicating
with illuminative light sources 551 other than the adjacent
illuminative light sources 551 and the optical communication device
501. The inter-lighting element light transmitting/receiving units
553 should be formed such that the length and orientation thereof
are adjustable to accommodate various lighting elements. Note that
in FIG. 9, the inter-lighting element light transmitting/receiving
units 553 are provided at both ends; alternatively they may be
provided at either end.
[0056] Such illuminative light sources 551 are fixed replacing the
existing fluorescent lamps of the lighting elements. In this case,
the illuminative light sources 551 should be attached directly to
the sockets to which fluorescent lamps are inserted. As a result,
electric power may be supplied to the illuminative light sources
551 from the sockets of the lighting elements. Illuminative light
data transmission is possible by regulating the length and
orientation of the inter-lighting element light
transmitting/receiving units 553.
[0057] The example shown in FIG. 7 shows an application to the
first embodiment according to the present invention shown in FIG.
1. In this case, the inter-lighting element light
transmitting/receiving units 553 attached to the respective
illuminative light sources 551 should face the optical
communication device 501. In this case, the inter-lighting element
light transmitting/receiving units 553 may be provided in a single
illuminative light source 551 of the respective lighting elements,
and the inter-adjacent light source light transmitting/receiving
units 552 may be used for data communication for the other
illuminative light sources.
[0058] The example shown in FIG. 8 shows an application to the
second embodiment according to the present invention shown in FIG.
234. In this case, the optical communication device 501
communicates with the inter-lighting element light
transmitting/receiving units 553 provided in a certain illuminative
light source 551 and communicates with the inter-adjacent light
source light transmitting/receiving units 552 or the inter-lighting
element light transmitting/ receiving units 553 for the other
illuminative light sources 551. When at least a single stroke
communication route is prepared, illuminative light communication
for all illuminative light sources 551 is possible. Needless to
say, multiple communication routes may be specified.
[0059] Note that FIGS. 7 and 8 show a case of attaching the
illuminative light sources 551 to the lighting elements embedded in
the ceiling. In such case, it is effective that the inter-lighting
element light transmitting/receiving units 553 are provided
protruding downward as shown in the drawings. Similarly, according
to the lighting elements to which the illuminative light sources
551 are attached, surrounding shades extend below the illuminative
light sources 551. In such cases, it is also effective that the
inter-lighting element light transmitting/receiving units 553 are
provided protruding downward.
[0060] FIG. 10 is an explanatory diagram of an illuminative light
communication system, according to a fourth embodiment of the
present invention. FIG. 11 is a diagram describing an exemplary
illuminative light source, according to the fourth embodiment of
the present invention. In the fourth embodiment, the light
transmitting/receiving units 522 are not provided in the
illuminative light sources 551 or in the lighting elements 502, and
the light emitting devices 521 and the light reception devices 523
are alternatively used. In this case, the illuminative light
sources 551, which comprise the light emitting devices 521 and the
light reception devices 523 as shown in FIG. 11, are used and
attached to the existing lighting elements, thereby constituting
the illuminative light communication system. As can be understood
through comparison with the illuminative light sources 551 shown in
FIG. 9, the inter-adjacent lighting source light
transmitting/receiving units 552 and the inter-lighting element
light transmitting/receiving units 553 are not provided in the
exemplary illuminative light sources 551 shown in FIG. 11.
[0061] The light reception devices 523 receive light (visible light
or infrared light) emitted from the light transmitting/receiving
unit 511 of the optical communication device 501, thereby receiving
data from the optical communication device 501. Light emitted from
the light emitting devices 521 is modulated in accordance with the
received data, and the resulting modulated illuminative light is
emitted. The terminal device 503 then receives and demodulates the
modulated illuminative light, allowing the terminal device 503 to
receive data.
[0062] On the other hand, in the case of transmitting data from the
terminal device 503, the light reception devices 523 in the
illuminative light sources 551 receive and demodulate modulated
light emitted from the terminal device 503, and then data from the
terminal device 503 is transmitted to the illuminative light
sources 551. Light emitted from the light emitting devices 521 is
modulated in accordance with the received data, and the resulting
modulated illuminative light is emitted. If the light
transmitting/receiving unit 511 of the optical communication device
501 receives and demodulates the modulated illuminative light, data
is transmitted from the terminal device 503 to the optical
communication device 501.
[0063] In this manner, in the fourth embodiment, both the optical
communication device 501 and the terminal device 503 emit light to
the illuminative light sources 551, and receive illuminative light
emitted from the illuminative light sources 551. This allows use of
illuminative light having large electric power and reduction in
influences of shadowing since the lighting elements are provided in
the ceiling where shadows are difficult to generate, thereby
providing favorable communication rather than the case of direct
optical communication between the optical communication device 501
and the terminal device 503. Needless to say, it is unnecessary to
extend a communication cable or an optical cable to the lighting
elements 502.
[0064] Note that in the example shown in FIG. 10, dedicated
illuminative light sources 551 as shown in FIG. 11 are used.
Similarly, the light transmitting/receiving units 522 may not be
provided in the lighting elements 502 in the case of using
dedicated lighting elements as shown in FIG. 1.
[0065] FIG. 12 is an explanatory diagram of an illuminative light
communication system, according to a fifth embodiment of the
present invention. In the drawing, 561 denotes street lights.
Currently, a mercury lamp, a sodium lamp, or a fluorescent lamp is
mainly used as the street lights 561 on a road. Alternatively, a
semiconductor light emitting device such as an LED may be applied.
When a semiconductor light emitting device is used as the
illuminative light source of the street lights 561, various pieces
of data may be transmitted through illuminative light to moving
vehicles and pedestrians. In this case, it is costly to provide a
communication cable or an optical cable to transmit data to the
respective street lights 561.
[0066] According to the present invention, the light
transmitting/receiving units 522 are provided in the street lights
561, and optical data communication among the street lights 561 is
provided through the air as with the aforementioned second
embodiment. This allows data transmission to the respective street
lights 561 and illuminative light data transmission by the street
lights 561. Such structure is economical since only electrical work
for the respective street lights 561 is necessary without providing
a communication cable or an optical fiber.
[0067] Note that the intervals between the street lights 561, for
example, of approximately 30 m on an expressway are longer than in
the aforementioned case of indoors. However, optical communication
is sufficiently possible. In addition, due to the present topology
or structure of the road, the orientation of the light
transmitting/receiving units 522 must be regulated so as for those
units to face adjacent street lights. This is not very difficult as
long as they have typical intervals between adjacent street lights.
Furthermore, a problem that the field of vision may be obstructed
by mist is expected. However, this is not a significant problem
since the intervals are approximately 30 m.
[0068] An example of optical communication among the street lights
provided on the road is shown as an outdoor network herein, and an
application according to the present invention is not limited to
this. For example, it is applicable to taxiway lights for air
crafts or illumination lamps in event halls.
[0069] Several embodiments and modified examples according to the
present invention have been described above. In the aforementioned
description, data is transmitted from the optical communication
device 501 to the lighting elements 502, the illuminative light
sources 551, or the street lights 561 (referred to as lighting
elements and the like). It is unnecessary for the respective
lighting elements and the like to transmit received data as is
through illuminative light. For example, a structure such that an
address or an ID is attached to a header of data to be transmitted
and that the lighting elements and the like select data in
accordance with that header and transmit the selected data via
illuminative light is possible. In addition, the lighting elements
and the like, which function as a relay or a router and are not
used for illuminative light data communication, may be
provided.
[0070] As described above, according to the present invention, when
each of lighting elements and illuminative light sources are used
for optical communication, data is transmitted thereto through the
air. Therefore, electrical work for providing a communication cable
or an optical fiber is unnecessary, allowing constituting an
illuminative light communication system at low cost. In this case,
the system may be structured using existing lighting elements,
allowing further reduction in cost. In addition, different from
power line communication, optical communication prevents problems
such as constraints on bandwidth, radio wave radiation, and
superimposition of noise from developing, allowing high-quality
data communication.
* * * * *