Optical: systems and elements – Deflection using a moving element – Using a periodically moving element
Reexamination Certificate
1999-02-23
2002-03-19
Pascal, Leslie (Department: 2733)
Optical: systems and elements
Deflection using a moving element
Using a periodically moving element
C359S199200, C359S199200, C359S199200
Reexamination Certificate
active
06359712
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a bidirectional optical communication apparatus and an optical remote control apparatus using this communication apparatus.
2. Description of the Related Art
Conventionally, a remote control apparatus is generally added to an audio visual apparatus such as a television or a CD player, thereby enabling various operations such as switching of television display channels, switching between recording and play and stop, selection from CDs, and turning-on and -off of the apparatus body despite a distance from the main apparatus body.
Such remote control apparatuses generally use infrared rays and are each composed of a set of a remote operation section and a remote-controlled section. In addition, the remote operation section is located on the operator's side, while the remote-controlled section is built into the audio visual apparatus (main apparatus) body. Furthermore, as shown in, for example,
FIG. 2
, a remote operation section
110
located on the operator' side has an input operation section
111
, a control section
112
, and a transmission section
113
. In addition, a remote-controlled section
120
built into the apparatus main body has a reception section
121
and a control section
122
.
In the remote operation section
110
, the input operation section
111
comprises a plurality of momentary switches to output to the control section
112
a switch signal indicating which switch has been pressed.
The control section
112
is composed of a well-known CPU, and based on the switch signal received from the input control section
111
, creates a transmitted instruction signal to output it to the transmission section
113
.
The transmission section
113
is composed of an infrared light-emitting diode and a diode drive circuit, and receives the instruction signal from the control section
112
to drive the infrared light-emitting diode based on this signal in order to radiate it to the external space as an optical signal.
In the remote-controlled section
120
, the reception section
121
comprises an infrared photodiode and at least an amplifier etc. (ex. A filter, and a comparator), and receives the infrared light from the remote operation section
110
to output an electric signal corresponding to the infrared signal.
The control section
122
receives the electric signal output from the reception signal
121
, and based on this signal, decodes the instruction sent from the remote operation section
110
to output it to a main control section
131
in a main apparatus body
130
.
The main control section
131
of the main apparatus body
130
then controls an operation such as switching of the television display channels or turning-on or -off of the power according to the instruction received from the remote-controlled section
120
.
Such a conventional remote control apparatus, however, transmits signals in only one direction, that is, from the remote operation section
110
to the remote-controlled section
120
. Thus, information such as the operational condition of the main apparatus body
130
cannot be displayed on the remote operation section
110
on the operator's side.
To display information such as the operational condition of the main apparatus body
130
on the remote operation section
110
, the information must be transmitted from the remote-controlled section
120
to the remote operation section
110
. Thus, as shown in
FIG. 3
, the remote operation section
110
may be provided with a reception section
114
and a display section
115
while the remote-controlled section
120
may be provided with a transmission section
123
. This configuration, however, has the following problems.
Half-duplex and full-duplex communication methods are known as bidirectional communication methods, but the half-duplex communication method requires a protocol for switching between transmission and reception. This results in complicated communication control and difficulties in achieving long continuous data communication due to the incapability of reception during transmission.
In addition, although the full-duplex communication method enables transmission and reception to be simultaneously executed to enable long continuous data communication, a light-emitting element and a light-receiving element are located adjacent to each other in order to reduce the size of the apparatus. Thus, as shown in
FIG. 4
, an infrared ray radiated from the transmission section is incident on the reception section, causing malfunction. Another cause of malfunction is the incidence on the reception section of an infrared ray radiated from the transmission section and reflected by walls of the room a number of times. One means for preventing such malfunction is to improve the light-emitting directionality of the light-emitting element and the light incidence directionality of the light-receiving element. This means eliminates the incidence on the light-receiving element of light radiated from the light-emitting element despite the proximity between the light-emitting and -receiving elements. In this case, however, the optical axes of two bidirectional lines must be aligned accurately, and this operation is very cumbersome and requires a large amount of time and labor. Therefor, these methods are not so practical.
BRIEF SUMMARY OF THE INVENTION
It is an object of the present invention to provide a bidirectional optical communication apparatus that does not require complicated communication control or accurate optical-axis alignment, as well as an optical remote control apparatus using this communication apparatus.
The present invention provides a bidirectional optical communication apparatus composed of a set of a first device comprising a first transmission section and a first reception section and a second device comprising a second transmission section and a second reception section, wherein the first and second devices use light to communicate data in both directions.
In this configuration, the first transmission section of the first device comprises a first light-emitting element that emits light corresponding to a transmitted digital signal and a first linear-polarization plate located on the light emission side of the fist light-emitting element according to the present invention. The first reception section comprises a first light-receiving element, and a second linear-polarization plate provided on the light incidence side of the first light-receiving element and located in such a way as to pass linear polarization having a polarization surface orthogonal to the polarization surface of linear polarization passing through the first linear-polarization plate.
Furthermore, the second transmission section of the second device comprises a second light-emitting element that emits light corresponding to a transmitted digital signal and a third linear-polarization plate located on the light emission side of the second light-emitting element to pass linear polarization having the plane of polarization of linear polarization passing through the second linear-polarization plate. The second reception section comprises a second light-receiving element; and a fourth linear-polarization plate provided on the light incidence side of the second light-receiving element and located in such a way as to pass linear polarization having the same plane of polarization as that of linear polarization passing through the first linear-polarization plate.
According to this bidirectional optical communication apparatus, when the first device communicates data to the second device, a transmitted digital signal is input to the first light-emitting element of the first transmission section, and the first light-emitting element emits light based on the digital signal.
Furthermore, the first linear-polarization plate radiates the light emitted from the first light-emitting element to the external space as linear polarization. The linear polarization radiated to the external space via the first linear-polarization pla
Lowe Hauptman & Gilman & Berner LLP
Pascal Leslie
Payne David C.
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