JP2000115081A - Optical communication device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To emit light toward the detection position of an opposite side without increasing the cost and space. SOLUTION: An optical communication module 10 has two PD(photodetector) chips PD1 and PD2 for photodetection which are so arranged that the lengthwise directions of sensitivity patterns (lobe) P1 and P2 slant outward from the center axis and two LED chips LED1 and LED2 for light emission which are so arranged that the lengthwise direction of a radiation pattern (lobe) P slants outward from the center axis as well outside the PD chips PD1 and PD2. The direction θ of an opposite light source (a) is detected from the difference between the photodetection signals of the PD chips PD1 and PD2 and the LED chips LED1 and LED2 are made to emit light selectively according to the direction θ.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical communication device which emits transmission light by detecting the direction of a communication partner when the position of the communication partner changes in a system for performing two-way communication via light such as infrared light.

[0002]

2. Description of the Related Art Generally, RS between computers is used for communication.
Wired communication methods such as H.232 have become widespread. However, in this communication method, there are problems such as complicated cable connection, poor contact, and inconsistency in shape due to irregularities in connector shape standards. In recent years, for example, US Pat.
No. 75,792, etc., an optical communication method using infrared rays or the like has been developed. The typical standard is IrD
A (Infrared Data Association) or the like, and in this standard, various optical specifications such as light emission intensity and light receiving sensitivity of a light emitting device are specified. In addition, since this standard generally assumes communication between desk-top computers and between desk-top computers and portable devices such as mobile terminals and digital cameras, it is expected that the devices will face each other manually. In addition, the emission angle is relatively narrow at about ± 15 ° on the assumption that signal quality is ensured.

FIG. 9 shows a conventional optical communication module 1,
An LED chip 2 for light emission and a photodetector (PD) chip 3 for light reception are arranged in the optical communication module 1.
In a normal product state, the LED chip 2 and the PD chip 3 are sealed in one resin package. The optical communication module 1 is incorporated in the own device 4 and performs bidirectional communication with another external device 5. In this case, LE
Each of the D chip 2 and the PD chip 3 has a relatively narrow radiation pattern (lobe) P _L and a sensitivity pattern (lobe) P _PD as shown in the figure, and the communication range is fixed in the own device 4. Relatively narrow.

[0004] By the way, it is premised that the devices are manually opposed to each other. However, when the number of partner devices is relatively large for the user, it is troublesome to face the own device for each communication partner each time. . Accordingly, in response to a request to fix the optical module itself when performing communication between mobile stations and to change only the optical module in accordance with the movement of the counterpart apparatus, for example, Japanese Patent Application Laid-Open No. 8-251106 and 9-
As disclosed in JP-A-148990 and JP-A-10-28092, there is also known a structure in which a directivity direction of an optical module can be manually changed by a swing mechanism in a housing.

Since the manual method requires complicated operations, an automatic method has also been proposed. As a method, means for detecting the position of the partner device and means for emitting light toward the detected position are required. Therefore, for example, as disclosed in Japanese Patent Application Laid-Open No. 4-364616, there is known an optical communication device which detects the position of a partner device based on a difference between light amount signals from a plurality of elements and mechanically emits light toward the detected position. Have been. As the former conventional example, there has been proposed an infrared remote control receiver for arranging a plurality of light receiving elements and using the element having the best communication state to receive the light, as shown in, for example, JP-A-3-62637. I have.

[0006]

However, the structure in which the light is emitted mechanically toward the detection position of the other party has a problem that the cost and the space are increased.

The present invention has been made in consideration of the above-described problems of the related art, and has as its object to provide an optical communication device that can emit light to a detection position of a destination without increasing cost and space.

[0008]

According to the present invention, in order to achieve the above object, a plurality of light receiving elements are provided so that a longitudinal direction of a lobe showing light receiving directivity is directed outward from a central axis, and a difference between light receiving signals is provided. Based on the detection result, any one of the plurality of light emitting elements provided so that the longitudinal direction of the lobe indicating the light emission directivity is directed outward from the central axis based on the detection result is selectively emitted. It is like that. That is, according to the present invention, a plurality of light receiving elements arranged around the central axis such that the longitudinal direction of the lobe indicating the light receiving directivity faces outward from the central axis, and the longitudinal direction of the lobe indicating the light emitting directivity is A plurality of light emitting elements arranged around the central axis so as to face outward from the central axis; direction detecting means for detecting a direction of a destination based on a difference between light receiving signals of the plurality of light receiving elements; and the direction An optical communication device comprising: a driving unit for selectively emitting any one of the plurality of light emitting elements based on a direction of a destination detected by the detecting unit.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory diagram showing an optical communication module and directivity in an embodiment of an optical communication device according to the present invention, FIG. 2 is a configuration diagram showing a cover of FIG. 1, and FIG. 4 is an explanatory diagram showing a direction detection signal, FIG. 5 is an explanatory diagram showing a radiation pattern of the LED chip of FIG. 1, FIG. 6 is an explanatory diagram showing a drive current of the LED chip of FIG. 1, and FIG. FIG. 8 is an explanatory diagram comparing a sensitivity pattern and a radiation pattern of an optical communication module with a conventional example, and FIG. 8 is a block diagram showing an optical communication device.

The optical communication module 10 shown in FIG. 1 has two light receiving units arranged such that the center lines in the longitudinal direction of the sensitivity patterns (lobes) P1 and P2 are directed obliquely outward from the central axis (θ = π / 2). PD chips PD ₁ , PD ₂ and this PD
It has a chip PD _1, LED of PD ₂ from the radiation pattern in the outer (lobes) P in the longitudinal direction two light emitting center line is disposed likewise from the central axis so as to face obliquely outward of the chip LED _1, LED _2. Around the PD chips PD ₁ and PD ₂ , the center lines in the longitudinal direction of the sensitivity patterns (lobes) P 1 and P 2 are directed obliquely outward from the center axis (θ = π / 2), and are hatched in FIG. As shown in FIG. 2, cylindrical covers T ₁ and T ₂ whose opening surfaces are obliquely cut are provided as shown in FIG. 2 so as to lower the sensitivity in the central axis direction. Then, these members are sealed with a resin package T ₃ that is lens processing. Note that LED chips LED ₁ and LED ₂ for light emission are arranged around this central axis.

Accordingly, as shown in FIG. 3, light from the partner light source a from the direction of the angle θ is transmitted to the PD chips PD ₁ and PD _2.
, Signals of different levels are obtained in accordance with the angle θ. Therefore, the difference (= O1−O2) between the light receiving signals of the PD chips PD ₁ and PD ₂ is obtained by the subtractor 13 so that the other light source a Can be detected.
FIG. 4 shows the relationship between the direction θ of the light source a and the difference signal O. Incidentally, the difference signal O in the region of the central axis (θ = π / 2) near is near zero, the difference signal O in the region received a large amount of PD chip PD ₁ is negative, PD
Difference signal O in the region received a large amount of chip PD ₂ is a positive difference signal O is always shown to be level-shifted to a plus.

By the way, as is apparent from the drawing, near the central axis (θ = π / 2), since the difference in the amount of light incident on the PD chips PD ₁ and PD ₂ is small, the covers T ₁ and T ₂ are not provided. In this case, the difference signal O becomes flat as shown by a broken line, and the switching accuracy of the LED chips LED ₁ and LED ₂ deteriorates. Then, by lowering the sensitivity in the central axis direction by the covers T ₁ and T ₂ , the central axis (θ =
The linearity of the difference signal O in the vicinity of (π / 2) can be improved, and the switching accuracy of the LED chips LED ₁ and LED ₂ can be improved.

FIG. 5 shows a radiation pattern (lobe) of the LED chips LED ₁ and LED ₂ . LED chip LE
D ₁ is arranged such that the center line of the radiation pattern area, near the boundary between the longitudinal center line of the radiation pattern LED chip LED ₂ are arranged so that near the boundary of the region. In addition, LED chip LE
The center of the combined radiation pattern when D ₁ and LED ₂ are turned on at the same time is arranged so as to be the central axis (θ = π / 2). Then, as shown in FIG.
D _1, LED ₂ respectively region is driven solely by the drive current I ₀ in the case of driven simultaneously drive current I _0/2 in order to reduce power consumption when the region. Therefore, as shown in FIG. 7, the radiation range and the sensitivity range can be expanded as compared with the conventional example (see FIG. 9).

Next, referring to FIG. 8, the overall configuration of the optical communication apparatus will be described.
Will be described. PD chip PD 1, PD_TwoBy photoelectric
The converted signals are supplied to amplifiers 11-1 and 11-2, respectively.
And the signals are amplified by the AGC circuits 12-1 and 12-2.
Then, the difference signal is calculated by the subtractor 13, and A
Is converted into a digital signal by the / D converter 14 and
Fetched by the processor 15. Microprocessor
The receiver 15 determines the destination based on the difference signal,
, Which is located, and according to the detection result
And sends a luminance control signal to the drivers 21-1 and 21-2.

The received signals amplified by the AGC circuits 12-1 and 12-2 are supplied to the comparators 16-1 and 12-2, respectively.
1 and 16-2, are compared with a reference value and are binarized. These two binarized data are combined by an OR gate 17, then decoded by a decoder (DEC) 18 and passed through a controller 19 to a microcontroller. It is sent to the processor 15. The transmission signal is transmitted from the microprocessor 15 via the controller 19 to the encoder (ENC) 20.
To the driver 21-1, 21-
2 to the LED chips LED ₁ , LED ₂
Turn on with the drive currents I ₀ and I _0/2 according to the luminance control signal.

[0016]

As described above, according to the present invention, a plurality of light receiving elements are provided so that the longitudinal direction of the lobe indicating the light receiving directivity is directed outward from the central axis, and the other light receiving element is provided based on the difference between the respective light receiving signals. Since the previous direction is detected, and based on the detection result, any one of the plurality of light emitting elements provided so that the longitudinal direction of the lobe indicating the light emission directivity faces outward from the central axis is selectively emitted. It is possible to emit light toward the detection position of the other party without increasing cost and space.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an optical communication module and its directivity in an embodiment of an optical communication device according to the present invention.

FIG. 2 is a configuration diagram showing a cover of FIG. 1;

FIG. 3 is an explanatory diagram illustrating a principle of detecting a destination direction.

FIG. 4 is an explanatory diagram showing a direction detection signal.

FIG. 5 is an explanatory diagram showing a radiation pattern of the LED chip of FIG. 1;

FIG. 6 is an explanatory diagram showing a driving current of the LED chip of FIG. 1;

7 is an explanatory diagram comparing a sensitivity pattern and a radiation pattern of the optical communication module of FIG. 1 with a conventional example.

FIG. 8 is a block diagram illustrating an optical communication device.

FIG. 9 is an explanatory diagram showing a conventional optical communication module and its directivity.

[Explanation of symbols]

PD _1, PD ₂ PD chip (light receiving element) LED _1, LED ₂ LED chip (light emitting element) T _1, T ₂ covers 15 microprocessor (direction detecting means) 21 - driver (driving means)

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (reference) H01L 33/00 H04B 9/00 G H01Q 3/00 H04B 10/24 F term (reference) 5F041 AA06 AA47 BB06 DA13 DA43 DA57 DA83 EE24 FF14 5F088 BA15 BB01 EA09 JA06 JA12 KA10 LA01 5J021 AA02 AA07 AB01 CA06 DA01 DA02 DB04 EA03 EA08 FA02 FA15 FA20 FA21 FA26 FA29 GA02 HA03 HA05 JA07 5K002 BA12 BA14 DA04 FA04 GA07

Claims (4)

[Claims] 1. A plurality of light-receiving elements arranged around the central axis such that the longitudinal direction of a lobe indicating light-receiving directivity is directed outward from the central axis, and the longitudinal direction of the lobe indicating light-emitting directivity is the central axis. A plurality of light-emitting elements arranged around the central axis so as to face outward from the light-receiving element; a direction detection means for detecting a direction of a destination based on a difference between light-receiving signals of the plurality of light-receiving elements; and the direction detection means. Driving means for selectively emitting any one of the plurality of light emitting elements based on the direction of the other party detected by the optical communication device. 2. The optical communication apparatus according to claim 1, wherein the direction detecting means detects the direction of the other party based on a value obtained by digitally converting a difference signal between the light receiving signals of the plurality of light receiving elements. . 3. The optical communication device according to claim 1, wherein the light receiving element is configured to have low sensitivity in a direction of the central axis. 4. The apparatus according to claim 1, wherein said driving means simultaneously emits n light-emitting elements and sets each driving current to 1 / n when the other party is located near the central axis. The optical communication device according to any one of the above.