JP3354802B2 - Optical communication device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an optical communication device,
In particular, the present invention relates to an infrared data communication device capable of communicating with a personal computer, an electronic organizer, an electronic still camera, other general home appliances, and information devices.

[0002]

2. Description of the Related Art In recent years, information devices such as personal computers and printers, portable information devices such as electronic notebooks, communication devices such as telephones and facsimile devices, home appliances such as electronic still cameras, and RS-232C cables have been connected between modems and the like. A technology has been developed in which an optical communication device is used instead of connection for performing one-to-one two-way communication or one-to-many communication in a cordless manner.

FIG. 9 is a block diagram of a general infrared data communication device. On the data transmission side 10, the transmission data 41 passed from the communication controller 50 is modulated by the modulation circuit 11 into an electric signal according to the infrared data communication method, and supplied to the light emitting element drive circuit 12. The light emitting element drive circuit 12 converts an electric signal into an infrared signal 31 by driving the infrared light emitting element 13 connected to the light emitting element current limiting resistor 14, and radiates it to another infrared data communication device. On the other hand, on the data receiving side 20, infrared light 32 emitted from another infrared data communication device is received by the light receiving element 23, converted into a current signal, and then amplified by the next-stage amplifier 22. Demodulator 2
1 and demodulates the received data 4 into the communication controller 50.
Send out as 2.

[0004] Infrared data communication systems include IrDA (In
frared Data Association) 1.0 system, IrDA1.
There are several methods such as one method and ASK (Amplitude Shift Keying) method. Usually, each infrared data communication method is
According to the communication distance and communication form required by the method,
Optical output, output directional characteristics, reception sensitivity, input directional characteristics, and the like are determined. IrDA is an industry organization (Infrared Data Association) that standardizes infrared data communication systems.
Abbreviation of IrDA1.0 system and IrDA1.1
The system is a communication system defined by this organization. Also,
The ASK (Amplitude Shift Keying) method is an infrared data communication method which is mounted on an electronic organizer or a word processor and shipped by the present applicant.

FIG. 10 shows an IrDA 1.0 system, IrDA
1 schematically illustrates output directivity characteristics required for the 1.1 system and the ASK system. The allowable light output range of the IrDA 1.0 system is 40 mW / sr to 500 mW / sr in the range of the LED optical axis ± 15 degrees as shown in the figure. Also, Ir
DA1.1 method is 100m in the range of LED optical axis ± 15 degrees
It is necessary to have a light output of W / sr to 500 mW / sr, and the ASK method varies depending on the product, but as shown in the lower part of FIG.
It is necessary to have an optical output of about 6 mW / sr. here,
mW / sr represents the light output per solid angle (1sr). The unit sr (steradian) is a dimensionless quantity indicating the three-dimensional spread of the vertex portion of the cone pair, and considers a cone having the center of the unit sphere as a vertex and a base on the unit sphere with respect to the unit sphere. When the bottom area of the cone is 1 cm ² , it is one solid angle (1sr).

FIG. 11 shows an IrDA 1.0 system, IrDA
1 schematically illustrates input directional characteristics required for the 1.1 system and the ASK system. The receiving sensitivity specification of the optical receiver is IrD
In the A1.0 system, 4 μW / c at ± 30 degrees or more of the receiving optical axis
m ^{2 to} 500 mW / cm ² , and in the IrDA1.1 system, 10 μW / cm ^{2 to} 500 mW /
cm ² . The ASK method differs depending on the product,
Here, 1.6 μW / cm ² to 1 at the received optical axis ± 13 degrees.
6 mW / cm ² .

As described above, since each communication system has a different optical output, output directivity, reception sensitivity, and input directivity, the conventional infrared data communication device is designed as a device dedicated to one infrared data communication system. . For this reason, communication between devices equipped with infrared data communication devices of different communication systems has not been considered, but recently, requests for infrared connection with various devices and addition of specifications of existing infrared data communication systems have been added. In order to comply with new regulations such as light output and the like, there is a demand for an infrared data communication device that can support a plurality of infrared data communication systems.

[0008]

In order to support a plurality of communication systems, it is necessary to satisfy all of the optical output, output directional characteristics, reception sensitivity, input directional characteristics, and the like. The simplest method is a method of preparing an optical communication device or a transmitter and a receiver for each communication system, and switching and using the optical communication device according to the communication system.

However, in this method, the number of optical communication devices to be mounted increases as the number of corresponding communication systems increases, so that there are difficulties in terms of the size and cost of the equipment. In recent years, in order to reduce the size and cost of equipment, there has recently been a demand for an optical communication apparatus that can support a plurality of communication systems with a set of a transmitter and a receiver.

However, as described with reference to FIG. 10, when the light output and output directivity are extremely different for each of the corresponding communication systems, the light output specifications of all the communication systems can be controlled by one light emitting element and current limiting resistor. Can not be satisfied.
Further, as described with reference to FIG. 11, when the specifications of the reception sensitivity and the reception directivity are extremely different for each infrared data communication system, if one light receiving element and an amplifier are used,
The required reception sensitivity is 1. as shown by a dashed line in FIG.
Since the dynamic range is too large as 6 μW / cm ^{2 to} 500 mW / cm ² , it is difficult to satisfy the light input specifications of all infrared data communication systems with one light receiving element and one amplifier.

As a method for changing the light output, FIG.
As shown in FIG. 2, two light emitting element current limiting resistors 15 and 16
And a switch 17. According to this method, the switch 17 is turned off in a certain method,
The two light emitting element current limiting resistors 15 and 16 are connected in series to the light emitting element 13 to reduce the current flowing through the light emitting element 13 to suppress the light output. In the case of another system, the switch 17 is turned on. Light emitting element 1 using only current limiting resistor 15
3, the light output can be increased by increasing the current flowing therethrough. However, it is necessary to increase the resistance and the switch as the number of corresponding communication systems increases, and in this system, the directional characteristics of the light emitting element 13 cannot be changed.

In order to change the light input, an APD (Avalanche Photodiode) 24 is used as a light receiving element as shown in FIG. 13, and a received signal is judged by a signal level judgment circuit 26.
A circuit that controls the increase or decrease of the photocurrent by changing the voltage applied to the APD 24 by the voltage control circuit 25 is known. However, in order to change the photocurrent, it is necessary to apply a voltage of several tens of volts even with a low-biased APD, and this method cannot be realized in a portable device having a limited power supply capability.

Japanese Patent Application Laid-Open No. 6-120897 discloses a circuit that enables an optical output level connected to an optical communication device to be automatically changed, thereby enabling optimal reception. I have. However, for this purpose, it is necessary that the optical communication device of the other party always adopts this circuit. The present invention has been made in view of such a problem, and an object of the present invention is to provide an optical communication device that can transmit and receive an appropriate level to any of a plurality of optical communication systems.

[0014]

According to the present invention, the magnitude of the optical output and / or the directional characteristic of the light emitting element provided in the optical communication device and the magnitude and / or the directional characteristic of the optical input of the light receiving element are communicated. The above object is achieved by controlling according to the method. This control can be performed by replacing an optical filter disposed in front of the light emitting element and the light receiving element, or by displaying an appropriate pattern on a liquid crystal panel disposed in front of the light emitting element and the light receiving element.

That is, the present invention provides an optical signal transmitting means,
In an optical communication device including an optical signal receiving unit and a communication controller for transmitting transmission data to the optical signal transmitting unit and receiving the received data from the optical signal receiving unit, the optical input / output characteristics of the optical signal transmitting unit and the optical signal receiving unit The communication controller has a function of outputting a control signal designating a communication method to the optical signal transmitting means, the optical signal receiving means, and the optical input / output characteristic controlling means. The means outputs transmission data as an optical signal modulated according to the specified communication method, and the optical signal receiving means demodulates the received optical signal according to the specified communication method and outputs it as reception data. The input / output characteristic control means controls the optical input / output characteristics of the optical signal transmitting means and the optical signal receiving means so as to conform to the designated communication system.

The control of the light input / output characteristics can be performed by an optical filter such as an infrared filter or a liquid crystal panel.
When controlling optical input / output characteristics with an optical filter,
The light input / output characteristic control means includes a plurality of optical filters and a means for selecting a desired optical filter from the plurality of optical filters. The light input / output characteristic is controlled by selecting an optical filter to be used according to a specified communication system. Control the magnitude and / or directional characteristics of the output. The magnitude of the light input / output can be controlled by the transmittance of the optical filter, and the directivity can be controlled by the spatial distribution of the light transmittance.

In the case where the control of the light input / output characteristics is performed by the liquid crystal panel, the light input / output characteristics control means includes a liquid crystal panel and a liquid crystal driving means for driving the liquid crystal panel. By changing the display pattern (picture, shading) of the liquid crystal panel, the magnitude of the light input / output and / or the directivity are controlled. The magnitude of the light input / output can be controlled by the density of the pattern displayed on the liquid crystal panel, and the directional characteristics can be controlled by the picture.

The outline of the present invention will be described below with reference to FIGS. FIG. 1 shows an example in which a plurality of optical filters (infrared filters) are replaced and used as light input / output characteristic control means, and FIG. 2 shows an example in which a liquid crystal panel is used as light input / output characteristic control means. In FIG. 1, the communication controller 50 specifies a communication method to the data modulator 11, the data demodulator 21, and the drive circuit 60 by a communication method control line 51 when starting communication. The drive circuit 60 selects the infrared filters 61 to 63 according to the specified communication system.

At the time of transmission, the electric signal of the transmission data 41 transmitted from the communication controller 50 is transmitted to the data modulator 11.
Accordingly, the communication controller 50 modulates the electric signal into an electric signal of the communication system specified by the control line 51 and inputs the electric signal to the light emitting element drive circuit 12. The light emitting element drive circuit 12 drives the light emitting element 13 whose current is limited by the light emitting element current limiting resistor 14, and the light emitting element 13 outputs an infrared signal 33. At this time, the infrared filter 61 disposed in front of the light emitting element 13 is selected by the drive circuit 60 which has received the designation of the communication method from the communication controller via the communication method control line 51. The infrared filter 61 restricts the light output and output directivity of the infrared signal 33 output from the light emitting element 13, and the infrared signal 31 having the optimum light output and output directivity for the specified infrared data communication system is used. Sent to the infrared data communication device.

At the time of reception, an infrared signal 32 transmitted from another infrared data communication device passes through an infrared filter 62 and is input to the light receiving element 23. The infrared filter 62 arranged in front of the light receiving element 23 also has the communication system control line 5.
The drive circuit 60 having a communication method designated by the communication controller 50 via the communication controller 1 selects a driver having appropriate characteristics. The illustrated infrared filter 63 is such a replacement infrared filter. The infrared signal 32 is converted into an infrared signal 34 whose characteristics have been changed so that the receiver can normally receive the signal by the operation of the infrared filter 62, and then input to the light receiving element 23.

In FIG. 2, the communication controller 5
0 indicates the data modulator 11, the data modulator 21, and the liquid crystal drive circuit 7 via the communication system control line 51 when starting communication.
Specify the communication method to 0. The liquid crystal drive circuit 70 displays a display pattern corresponding to the specified communication method on a liquid crystal panel 71 disposed in front of the light emitting element 13 and the light receiving element 23.

At the time of transmission, the electrical signal of the transmission data 41 sent from the communication controller 50 is transmitted to the data modulator 1
The signal is modulated by 1 into an electric signal of the communication method designated by the communication controller 50 and supplied to the light emitting element drive circuit 12. The light emitting element drive circuit 12 includes a light emitting element current limiting resistor 1.
4 drives the light-emitting element 13 whose current is limited, and outputs an infrared signal 33 from the light-emitting element 13. At this time, the liquid crystal driving circuit 70 which has received the designation of the communication method from the communication controller 50 causes the liquid crystal panel 7 on the light emitting element 13 side to operate.
1, a predetermined display pattern is displayed. LCD panel 71
The display pattern serves as light output characteristic control means and changes the characteristics of the infrared signal 33. Thus, the infrared signal 33
Is limited in light output and output directivity, and is converted into an infrared signal 31 having an optimum light output and output directivity for the designated infrared data communication system and transmitted to another infrared data communication device.

At the time of reception, the infrared signal 32 transmitted from another infrared data communication device passes through the pattern displayed on the liquid crystal panel 71 and is input to the light receiving element 23. At this time, the infrared signal 32 becomes an infrared signal 34 limited to light that can be normally received by the receiver due to the filtering effect of the display pattern displayed on the liquid crystal panel 71, and is input to the light receiving element 23. According to the present invention, by controlling the light input / output characteristic control means disposed in front of the light emitting element and the light receiving element in accordance with the infrared data communication method, a plurality of infrared rays can be transmitted by a set of transmitter and receiver. Compatible with data communication systems.

[0024]

Embodiments of the present invention will be described below in detail with reference to the drawings. An example of the infrared data communication device according to the present invention will be described with reference to FIGS. FIG. 3 is a block diagram of an example of an infrared data communication apparatus according to the present invention using a liquid crystal panel as light input / output characteristic control means. FIG. 4 is a liquid crystal corresponding to the IrDA 1.0 system, the IrDA 1.1 system, and the ASK system. It is a figure showing an example of a pattern of a panel. FIG. 5 is a diagram showing the output directivity of the infrared data communication device according to the present invention, and FIG. 6 is a diagram showing the input directivity.

The light output of the transmitter is adjusted in accordance with the one having the largest output and the broadest directivity among the corresponding infrared data communication systems. As described above, the IrDA1.0 system is 40 mW / sr to 500 m in a range of the LED optical axis ± 15 degrees.
The W / sr, IrDA1.1 system needs to have a light output of about 100 mW / sr to 500 mW / sr in the range of LED optical axis ± 15 degrees, and the ASK system needs to have a light output of about 16 mW / sr in the range of LED optical axis ± 13 degrees. is there. Therefore, the LED current limiting resistor 104 is adjusted so that the optical output of the transmitter is adjusted to about 100 mW / sr at ± 15 degrees of the optical axis in accordance with IrDA1.1 having the largest minimum optical output. When such an adjustment is made, the light output on the optical axis differs depending on the characteristics of the LED. Here, the light output on the optical axis is 120 mW / sr.
It is assumed to be about.

The receiving sensitivity of the receiver is adjusted so as to have the lowest sensitivity among the corresponding infrared data communication systems, and the dynamic range and the input directivity are large. As described above, the receiving sensitivity specification of the optical receiver is IrD
4 μW / cm ^{2 to} 500 mW / c for A1.0 method
m ² , 10 μW / cm ^{2 to} 500 for IrDA1.1 system
mW / cm ² , 1.6 μW / cm ² -16 for ASK method
mW / cm ² . Here, ASK with the lowest sensitivity
The minimum sensitivity is set to 1.6 μW / cm ² according to the system, and the maximum sensitivity is determined according to the IrDA 1.0 system having the largest dynamic range. In the IrDA 1.0 system, the specification of the range of the optical input that can be input to the receiver is 4 μW / cm ^2.
From 500 mW / cm ² , the dynamic range is set to 102 dB from the following equation. 20 · log (500/4) = 102 Therefore, the maximum sensitivity of the receiver whose minimum sensitivity is adjusted to 1.6 μW / cm ² and dynamic range is adjusted to 102 dB is adjusted to 201.4 mW / cm ² from the following equation. 1.6 × invlog (102/20) = 201.4 Here, “invlog” represents an inverse function of logarithm (log).

In a standby state in which no communication is performed, the first
Of the control line 501 and the second control line 502 are both L
ow. The communication controller 500 outputs the logical signals shown in Table 1 below to the first control line 501 and the second control line 502, and outputs the data modulator 101, the data demodulator 201, and the liquid crystal drive of the infrared data communication device. Circuit 70
Specify the infrared data communication method to be set to 0.

[0028]

[Table 1]

At the same time, the liquid crystal drive circuit 700 controls the control line 50
1 and LED for the system specified by control line 502
The patterns shown in FIG. 4 are displayed on the liquid crystal panels 103 and the PIN-PD 203, respectively. The pattern on the left side of FIG. 4 is a liquid crystal display pattern on the transmitting side, and the pattern on the right side is a pattern on the receiving side. (A) is a standby state,
(B) IrDA 1.0 system, (c) IrDA 1.1
The method (d) corresponds to the ASK method. The area of each cell in the display pattern of the liquid crystal panel is LED or P
It is sufficiently smaller than the surface area of IN-PD.

In the standby state, as shown in FIG.
On the liquid crystal panel, a pattern such that the transmittance is 100% over the entire surface on both the transmitting side and the receiving side is displayed. Transmittance 100
%, The transmittance may be set to 0% or an arbitrary transmittance.

As shown in FIG. 4B, IrDA 1.0
In the case of the system, the pattern (transmission side pattern) displayed in front of the LED 103 does not display anything near the optical axis of the LED 103 (transmittance 100%), and has a transmittance of 40% near the LED optical axis ± 15. Liquid crystal pattern. as a result,
The infrared signal 301 transmitted through the liquid crystal panel 701 is compared with the infrared signal 303 before passing through the liquid crystal panel 701,
Although the light output on the optical axis of the LED 103 does not change,
The optical output of the optical axis 103 at ± 15 degrees is 40 mW / sr as calculated by the following equation from the original optical output of the transmitter, 100 mW / sr. Therefore, the infrared signal 3
The light output of No. 01 is attenuated at an angle portion deviating from the optical axis, and the directivity is increased as shown by the curve b in FIG. 100 mW / sr × 40% = 40 mW / sr

On the other hand, the display pattern (reception-side pattern) in front of the PIN-PD 201 is constituted by a liquid crystal pattern in which half of the 6 × 6 cells have a transmittance of 0% and the other half have an equivalent ratio of 80%. I have. Therefore, the liquid crystal panel 701 displaying this pattern allows the data receiving side 20 to be displayed.
Is 4 μW / c as shown in FIG.
m ² ~500mW / cm ² from 1.6μW / cm ² ~20
Attenuated to 0 mW / cm ² . As described above, the data receiving side 20 is designed to receive light of 1.6 μW / cm ^{2 to 200} mW / cm ² . Therefore, the infrared data communication device shown in FIG. 3 satisfies the IrDA 1.0 reception specification.

Further, as shown in FIG.
In the case of the 1.1 method, the pattern (transmission-side pattern) displayed in front of the LED 103 is a pattern in which the transmittance is 100% over the entire surface. Therefore, I
The light output of the infrared signal 301 when transmitted by the rDA1.1 method is, as shown by a curve a in FIG.
It is equal to the infrared signal 303 before passing through 1. On the other hand, PIN
-In the pattern (reception-side pattern) displayed in front of the PD 201, half of the 6 × 6 cells have a transmittance of 0%,
The other half is a liquid crystal pattern having a transmittance of 32%.

Therefore, the intensity of light input to the data receiving side 20 by the liquid crystal panel 701 displaying this display pattern is 4 μW / cm, as shown in FIG.
From ^{2 ~500mW / cm 2 1.6μW / cm} 2 ~80m
Attenuated to W / cm ² . As described above, the data receiving side 20 is designed to receive light of 1.6 μW / cm ^{2 to 200} mW / cm ² . Therefore, IrDA
When a 1.1-mode liquid crystal display pattern is displayed, the infrared data communication apparatus of FIG. 3 satisfies the IrDA 1.1-mode reception specifications.

Further, as shown in FIG.
In the case of the system, the pattern (transmitting side pattern) displayed in front of the LED 103 is an LED composed of 4 × 4 cells.
Near the optical axis, half of the squares have a transmittance of 0%, the other half has a transmittance of 27%, and a transmittance of around ± 15 degrees is zero.
%. As shown by a curve c in FIG. 5, the infrared signal 301 generated from the transmitting side 10 has a higher directivity and a stronger directivity than the infrared signal 303 before passing through the liquid crystal panel 701 (curve a in FIG. 5). LED10
The optical output on the optical axis 3 is also the original optical output of the transmitter 1
From 20 mW / sr, 16.2 as calculated by the following equation:
mW / sr. 120 mW / sr × 50% × 27% = 16.2 mW / s
r

On the other hand, the display pattern on the receiving side 20 is a pattern having a transmittance of 100% over the entire surface. The intensity of light input to the receiver 20 of the data by the liquid crystal panel 701 that displays the display pattern, as shown in FIG. 6, the range of 1.6μW / cm ² ~16mW / cm ² . Since the data receiving side 20 has the minimum sensitivity in accordance with the ASK method and the dynamic range is equal to or greater than the dynamic range of the ASK method, the infrared data communication apparatus in FIG. 3 can satisfy the ASK method receiving specification.

As described above, the infrared data communication apparatus according to the present invention arranges the liquid crystal panel 701 in front of the LED 103 on the data transmission side 10 and in front of the PIN-PD 203 on the data reception side 20 according to the infrared data communication system. By changing the pattern displayed on the liquid crystal panel 701, data communication can be performed by any of the IrDA 1.0 system, the IrDA 1.1 system, and the ASK system.

For example, when communicating by the IrDA 1.0 system, the communication controller 500 sets the control line 501 to Hig.
h, the control line 502 is set to Low, and the data modulator 101,
The data demodulator 201 is operated in the IrDA1.0 system. At the same time, the liquid crystal driving circuit 700, which has received the designation of the communication method from the communication controller 500, displays the pattern for IrDA1.0 shown in FIG. 4B on the LED 103 side and the PIN-PD 203 side of the liquid crystal panel 701, respectively. I do.

At the time of transmission, the electric signal of the transmission data 401 sent from the communication control 500 is
1, the communication controller 500 causes the control lines 501 and
The signal is modulated into an IrDA 1.0 electrical signal designated by 502 and supplied to the LED drive circuit 102. LED
The drive circuit 102 drives the LED 103 connected to the LED current limiting resistor 104, and the LED 103 outputs an infrared signal 303. At this time, the display pattern displayed on the LED side of the liquid crystal panel 701 by the liquid crystal driving circuit 700 serves as an infrared filter having a spatial transmittance distribution, restricts light output and output directivity, and outputs the infrared signal 3.
03 is the optimal light output for the specified IrDA1.0 system,
An infrared signal 301 having output directivity is transmitted to another infrared data communication device.

At the time of reception, an infrared signal 302 transmitted from another infrared data communication device passes through a pattern for IrDA 1.0 system displayed on a liquid crystal panel 701 and is transmitted through a PI
It is input to the N-PD 203. At this time, the infrared signal 30
Reference numeral 2 denotes a filtering effect of a display pattern displayed on the liquid crystal panel 701, which is an infrared signal 304 that can be normally received by the receiver. After the output of the PIN-PD 203 is amplified by the amplifier 202, the data demodulation circuit 201
, The control line 501,
The demodulated received data 402 is supplied to the communication controller 500 by demodulation according to the IrDA 1.0 system designated by 502.

Since the display pattern shown in FIG. 4 is rectangular, the light output characteristics in the vertical and horizontal directions and the diagonal direction with respect to the display pattern are particularly large in the case of the IrDA1.1 system shown in FIG. Although the light output characteristics are slightly different from each other, the same light output characteristics can be obtained in any direction by increasing the number of pattern display units (squares) of the liquid crystal panel 701 to form a smooth circular display pattern.

The liquid crystal panel 7 as the light input / output characteristic control means
The same effect can be obtained by using a plurality of optical filters having a spatial distribution of transmittance and optical filter replacing means instead of the liquid crystal driving circuit 700 and replacing the optical filters. An example in which a plurality of infrared filters are used as light input / output control means will be described with reference to FIGS.

FIG. 7 is a diagram showing an example of a combination of infrared filters capable of obtaining the same effect as the display pattern of the liquid crystal panel shown in FIG. 4. The pattern on the left side of FIG. The pattern on the right side shows the transmittance distribution of the infrared filter on the receiving side. (A) is a standby state, (b) is an IrDA1.0 system,
(C) corresponds to the IrDA1.1 system, and (d) corresponds to the ASK system. Limiting the light output is achieved by changing the transmittance of the infrared filter. The directional characteristics can be realized by limiting the aperture ratio of the filter or by using an infrared filter having a partially different transmittance.

In the standby state, as shown in FIG.
Infrared filter with 100% transmittance on both transmitting and receiving side
For simplicity, a simple opening may be used or light may be shielded. In the case of the IrDA 1.0 system, as shown in FIG.
An infrared filter having a transmittance of 40% at the periphery is set to 0%. On the receiving side, an infrared filter whose transmittance is set to 40% over the entire surface is arranged.

In the case of the IrDA1.1 system, as shown in FIG. 7 (c), an infrared filter having a transmittance of 100% is arranged on the entire transmission side, and a transmittance of 16% is set on the entire reception side. Place an infrared filter. Also, ASK
For the system, the transmittance near the optical axis of the LED is 1 on the transmitting side.
An infrared filter with a transmittance of 4% and a peripheral portion of 0% is arranged, and an infrared filter with a transmittance of 100% is arranged on the entire receiving side.

FIG. 8 shows the LED 103 or PIN-PD2.
FIG. 11 is a diagram illustrating an example of an installation and replacement mechanism of an infrared filter with respect to the third embodiment. (A) is a schematic perspective view of an installation and replacement mechanism of an infrared filter, (b) is a cross-sectional view thereof,
(C) is an explanatory view of the drive mechanism. Here, LED1
03, the same mechanism can be used for the PIN-PD 203.

As shown in FIG. 7, the infrared filter is used during standby, for the IrDA1.1 system,
Four sheets for rDA1.0 system and ASK system are prepared,
They are mounted in a filter cylinder 601 rotatable around the LED 103 at 90 ° intervals in the rotation direction.
The filter tube 601 is connected to the LED 103 by the motor 602.
Is rotated in steps of 90 ° around the
The infrared filter located in front of D103 is selected.

As shown in FIG. 8C, the motor control circuit 603 receives a communication system designation from the communication controller via the communication system control lines 501 and 502. The designation of the communication method is performed by outputting the logical signals shown in Table 1 to the control lines 501 and 502. Motor control circuit 603
Rotates the gear 605 meshing with the gear 604 provided on the filter cylinder 601 by the motor 602, and positions an infrared filter suitable for the specified communication system in front of the LED 103.

Here, the present invention relates to the ASK method, IrDA
Although the example applied to the 1.0 system and the IrDA 1.1 system has been described, the present invention relates to another optical communication system, for example, “IE
Needless to say, the present invention can be applied to a diffusion type infrared LAN such as "EE802.11 IR", and can be easily applied to input / output adjustment in a LAN device using an optical fiber.

[0050]

As described above, according to the present invention, a pair of transmitter and receiver can support a plurality of infrared data communication systems. Further, since the communication system control line is used as the control line, a desired effect can be obtained while maintaining the conventional interface. Also, unlike the case of using the APD, a high voltage is not required. Further, when a liquid crystal panel is used, it is excellent in quietness, downsizing and high-speed switching as compared with a mechanical light limiting shutter.

[Brief description of the drawings]

FIG. 1 is a block diagram of an optical communication device according to the present invention using a plurality of optical filters as light input / output characteristic control means.

FIG. 2 is a block diagram of an optical communication device according to the present invention using a liquid crystal panel as an optical input / output characteristic control unit.

FIG. 3 is a block diagram of an example of an infrared data communication device according to the present invention using a liquid crystal panel as light input / output characteristic control means.

FIG. 4 is a diagram showing an example of a pattern of a liquid crystal panel corresponding to the IrDA1.0 system, the IrDA1.1 system, and the ASK system.

FIG. 5 is a diagram showing output directivity characteristics of the infrared data communication device according to the present invention.

FIG. 6 is a diagram showing input directivity characteristics of the infrared data communication device according to the present invention.

FIG. 7 is a diagram showing an example of a combination of infrared filters.

FIG. 8 is a diagram illustrating an example of an installation and replacement mechanism of an infrared filter.

FIG. 9 is a block diagram of a general infrared data communication device.

FIG. 10 shows IrDA 1.0 system, IrDA 1.1 system,
FIG. 4 is an explanatory diagram of output directivity characteristics required for the ASK method.

FIG. 11 shows IrDA1.0 system, IrDA1.1 system,
FIG. 4 is an explanatory diagram of an input directivity characteristic required for the ASK method.

FIG. 12 is an explanatory diagram of a transmitter for coping with output characteristics of a plurality of conventional infrared data communication systems.

FIG. 13 is an explanatory diagram of an optical amplifier using an APD.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Transmission side, 11 ... Data modulator, 12 ... Light emitting element drive circuit, 13 ... Light emitting element, 14, 15, 16 ... Light emitting element current limiting resistance, 17 ... Switch, 20 ... Receiving side, 21 ...
Data demodulator, 22 ... Amplifier, 23 ... Light receiving element, 24 ...
APD, 25: voltage control circuit, 26: signal level determination circuit, 31, 32, 33, 34: infrared signal, 41: transmission data, 42: reception data, 50: communication controller,
51: communication system control line, 60: drive circuit, 61, 62,
63: infrared filter, 70: liquid crystal drive circuit, 71:
Liquid crystal panel, 101: data modulator, 102: LED drive circuit, 103: LED, 104: LED current limiting resistor, 201: data demodulator, 202: amplifier, 203 ...
PIN-PD, 301, 302, 303, 304: infrared signal, 401: transmission data, 402: reception data, 5
00: communication controller, 501, 502: communication system control line, 601: filter cylinder, 602: motor, 603
.., Motor control circuit, 604, 605, gear, 700, liquid crystal drive circuit, 701, liquid crystal panel

Continued on the front page (51) Int.Cl. ⁷ Identification code FI H04B 10/22

Claims (5)

(57) [Claims] 1. An optical signal transmitting means, an optical signal receiving means,
A communication controller for transmitting transmission data to the optical signal transmission means and receiving reception data from the optical signal reception means; controlling an optical input / output characteristic of the optical signal transmission means and the optical signal reception means; An optical input / output characteristic control unit, wherein the communication controller has a function of outputting a control signal designating a communication system to the optical signal transmitting unit, the optical signal receiving unit, and the optical input / output characteristic control unit; The light input / output characteristic control means selects at least one of a light input / output magnitude and a directional characteristic between the light signal transmitting means and the light signal receiving means so as to conform to a specified communication method. Optical communication device. 2. The optical output of the optical signal transmitting means is adjusted according to one having the largest output and wide directivity among optical communication systems which the optical communication device can support. The optical communication device according to claim 1, wherein 3. The receiving sensitivity of the optical signal receiving means is adjusted in accordance with the optical communication system which has the smallest sensitivity among the optical communication systems which the optical communication device can support and which has a large dynamic range and input directivity. The optical communication device according to claim 1, wherein: 4. The optical input / output characteristic control means includes a plurality of optical filters and a means for selecting a desired optical filter from the plurality of optical filters, and an optical filter used in accordance with a designated communication system. Selecting at least one of the magnitude of light input and output and the directional characteristic of the optical signal transmitting means and the optical signal receiving means so as to be compatible with a designated communication system. Item 2. The optical communication device according to Item 1. 5. The light input / output characteristic control means includes a liquid crystal panel and a liquid crystal driving means for driving the liquid crystal panel, and changes a display pattern of the liquid crystal panel according to a specified communication system. 2. The optical communication according to claim 1, wherein at least one of the magnitude of light input / output and the directivity of the optical signal transmitting means and the optical signal receiving means is selected so as to conform to a designated communication system. apparatus.