JP2006333188A - Optical spatial transmitter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical spatial transmitter capable of attaining both high-speed transmission and flexibility about the installation of an optical receiver. <P>SOLUTION: A light source control part 104 switches a modulated signal 14 from any port of n output ports and outputs the modulated signal 14 according to a control signal 15, point light sources 101a to 101g convert an output signal from a corresponding port into optical signals 11a to 11g and output the optical signals 11a to 11g, and an optical coupling part 102 transmits optical signals to space and adjusts optical paths so that regions 13a to 13g that are respectively irradiated with the optical signals in the space may be adjacent to one another and different from one another. An optical receiving part 103 is arranged within an irradiation range 13 composed of the irradiation regions 13a to 13g, receives any of the optical signals 11a to 11g, converts the received optical signal into an electric signal (modulated signal) 14' and outputs the electric signal 14'. Further, the light source control part 104 switches the output signal to the point light sources so as to make the optical signals 11a to 11g sequentially scan the irradiation regions. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an optical space transmission device that performs high-speed transmission while reducing the setting accuracy of an optical transmission device while suppressing danger to human vision when performing wireless communication by emitting light into free space.

  FIG. 5 is a block diagram showing a configuration of a conventional optical space transmission device (see, for example, Patent Document 1). In FIG. 5, the present optical space transmission apparatus includes an optical transmission unit 500 and an optical reception unit 503. The light source 501 and the optical coupling unit 502 constitute an optical transmission unit 500, and the optical detection unit 503a The receiving unit 503 is configured.

  About the space optical transmission apparatus comprised as mentioned above, the operation | movement is demonstrated using FIG. The optical transmission unit 500 receives the modulation signal 54, adds a predetermined bias value (bias current), and then inputs the modulation signal 54 to the light source 501, for example, converts the light signal 51 by a direct light intensity modulation method and outputs the light signal 51. The optical coupling unit 502 is configured by an optical component such as a lens, and irradiates a predetermined range 53 by adjusting the optical path of the optical signal 51. The optical receiver 503 (optical detector 503a) is arranged in the light irradiation range 53, receives at least a part of the power of the optical signal 51, converts it into an electric signal 54 ', and outputs it.

  Here, in the optical space transmission apparatus having this configuration, the optical signal 51 transmitted from the optical transmission unit 500 may enter the human eye and burn the retina, causing injury. For this reason, in Japan, for example, the radiated light power to the space is limited / defined by the Association of Radio Industries and Businesses (ARIB) under the Ministry of Internal Affairs and Communications. For example, a predetermined distance Daye from the light emitting end surface 500a of the optical transmission unit 500 The total light power Ptotal that irradiates a predetermined range 50 separated by a distance is set to be equal to or less than a predetermined value.

  On the other hand, in the optical transmission system, the higher the optical power input to the optical receiver (optical detection element), the higher the received signal quality (SNR) and the higher the transmission speed. Therefore, as shown in FIG. 5, when the optical signal output from the light source 501 is diffused, the total optical power input to the optical detection unit 503a is reduced, so it is difficult to ensure a high SNR and increase the transmission rate. I can't. Therefore, in the actual optical space transmission apparatus, the output optical signal from the light source 501 is collected by the optical coupling unit 502 (51a), and the optical signal is transmitted without being diffused. As a result, the total power of the optical signal output from the light source 501 is input to the optical detection unit 503a, and the SNR of the received signal is increased to enable high-speed transmission.

  As described above, in an optical space transmission device using a point light source or condensing, while the radiated light power is limited in consideration of eye safety, in order to ensure a desired received signal quality, an optical signal irradiation range is set. Narrowed to enable high-speed optical transmission. However, due to the reduction of the optical signal irradiation range, there is a problem that high accuracy is required for installation of the optical receiver, and flexibility as a wireless transmission device / terminal is lowered.

  FIG. 6 is a block diagram showing another configuration of a conventional optical space transmission device (see, for example, Patent Document 2). In FIG. 6, the present optical space transmission device includes an optical transmission unit 600 and an optical reception unit 603. The optical transmission unit 600 is configured by a light source 601 and an optical coupling unit 602, and an optical reception unit 503a receives the optical reception. Part 503 is configured.

  About the space optical transmission apparatus comprised as mentioned above, the operation | movement is demonstrated using FIG. The optical transmitter 600 receives the modulated signal 64, adds a predetermined bias value, and then injects it into the light source 601. The light source 601 is a surface light source composed of, for example, a plurality of light emitting elements 601 a to 601 g, and blinks all at once with the modulation signal 64 and outputs an optical signal 61. The optical signal output from the light source 601 is diffused at a predetermined angle, and at least part of the optical signal is adjusted by the optical coupling unit 602 to irradiate the predetermined range 63. The optical receiving unit 603 (optical detection unit 603a) is arranged in the irradiation range 63, receives a partial power of the optical signal 61, converts it into an electric signal 64 ', and outputs it.

  In the optical space transmission apparatus of this configuration, compared with the case of FIG. 5, the diffusion angle of the optical signal is increased to secure a wider irradiation range 63 in which the optical signal can be received, and the optical receiving unit 603. The flexibility regarding the installation of can be improved. Also in this configuration, as in the case of FIG. 5, from the viewpoint of eye safety, the total optical power Total that irradiates a predetermined range 60 that is a predetermined distance Dee from the light emitting end surface 600 a of the optical transmitter 600 is limited. However, in consideration of the human viewing angle when the light source is viewed, a value larger than the total optical power Ptotal in FIG. 5 is allowed.

As described above, in an optical space transmission device using a surface light source or diffused light, the radiated light power limitation of an optical transmitter can be relaxed, and an optical signal can be irradiated over a wide range to enable more flexible optical transmission. To do. However, due to the large diffusion angle of the optical signal, the total optical power that can be received by the optical receiver is smaller than in the case of FIG. 5, and it is difficult to increase the transmission rate. ing.
JP-A-1-192233 JP-A-9-167996

  As described above, the conventional optical space transmission device can achieve high-speed transmission by narrowing the light signal irradiation range and increasing the received light power in the configuration using the point light source, while providing high accuracy for installing the optical receiver. In a configuration using a surface light source, the light signal irradiation range is increased to enable flexible installation of the optical receiver, but the received light power is reduced and the transmission rate is limited. have.

  Therefore, an object of the present invention is to provide an optical space transmission device that can achieve both high-speed transmission and flexibility in installing an optical receiver.

  A first invention is an optical transmission apparatus including an optical transmission unit and an optical reception unit. The optical transmission unit inputs a modulation signal and a control signal, and a plurality of modulation signals (n is 2 in accordance with the control signal). The light source driving unit selectively outputs from any one of the output ports of the above integers) and the n output ports of the light source driving unit. The output signals are converted into optical signals and output. The light receiving unit includes an optical detection unit that inputs any of the optical signals output from the n light sources of the light emitting unit, converts the light signals into electrical signals, and outputs the electrical signals.

  In a second aspect based on the first aspect, the optical signal output from the optical transmitter scans a desired spatial range in a predetermined procedure for a predetermined time.

  In a third aspect based on the second aspect, the optical signal output from the optical transmitter is in a state where the level of the electrical signal output from the optical receiver is maximized, or the signal quality is optimal. Stop scanning.

  According to a fourth invention, in the first and second inventions, the optical signals output from the n light sources are both output through the same opening provided in the optical transmitter.

  According to a fifth invention, in the first and second inventions, the optical signals output from the n light sources irradiate different spatial ranges.

  In a sixth aspect based on the first and second aspects, the optical signals output from the n light sources irradiate spatial regions adjacent to each other.

  In a seventh aspect based on the first to sixth aspects, the n light sources are arranged adjacent to each other on the same plane.

  In an eighth aspect based on the first to sixth aspects, the n light sources are arranged adjacent to each other on the concave surface.

  According to a ninth invention, in the first to sixth inventions, all or a part of the injected current output from the light source driver is inserted between the n output ports of the light source driver and the n light sources. In addition, m (m is an integer equal to or less than n) delay adjustment units that respectively add predetermined delay times are further provided.

  A tenth aspect of the invention is an optical transmission apparatus including an optical transmission unit and an optical reception unit, wherein the optical transmission unit inputs a modulation signal and a control signal, and the modulation signal is selected from any of n output ports according to the control signal. A light source driving unit that selectively outputs from a plurality of ports, m delay adjusting units that respectively add a predetermined delay time to all or some of the injection currents output from the n output port of the light source driving unit, and a light source driving unit N diffused light sources provided corresponding to the n output ports of the light source, which receive the output signal or the output signal from the delay adjustment unit of m, and convert and output to a diffused optical signal in which the irradiation regions overlap each other The light receiving unit includes an optical detection unit that inputs any one of the optical signals output from the n diffused light sources of the light emitting unit, converts the light signal into an electrical signal, and outputs the electrical signal. Part is output from n diffused light sources In a predetermined area within the entire illumination range formed by the irradiation area of the signal, the phase of the plurality of optical signals to match, to adjust the delay time.

  In an eleventh aspect based on the tenth aspect, the n diffused light sources are multimode light sources.

  In a twelfth aspect based on the eleventh aspect, the multimode light source is an LED (Light Emission Diode).

  In the first aspect of the present invention, an optical space transmission device that is excellent in flexibility by relaxing one of the plurality of light sources and receiving one of the optical signals, thereby reducing the installation accuracy of the optical receiver. I will provide a.

  In the second aspect of the invention, by switching light sources of a plurality of light sources, the optical signal is spatially scanned, the substantial irradiation range is expanded, the installation accuracy of the light receiving unit is relaxed, and excellent in flexibility. An optical space transmission device is provided.

  In the third aspect of the invention, the optical signal is spatially scanned by switching the plurality of light sources to emit light, and the scanning is stopped in a state in which the electrical signal quality of the optical receiver is maximized, whereby the optical receiver Provided is an optical space transmission device that enables high-speed transmission while relaxing installation accuracy.

  In the fourth, fifth, and sixth inventions, the number of light sources used in the optical transmitter is optimized by reducing the installation accuracy of the optical receiver by scanning the optical signal more efficiently. An optical space transmission apparatus having a simple structure is provided.

  In the seventh and eighth inventions, the number of light sources used in the optical transmission unit is optimized, and signal quality degradation is suppressed even when the optical reception unit receives optical signals output from a plurality of light sources simultaneously. Thus, a high-quality optical space transmission device is provided.

  In the ninth aspect of the invention, even when the optical receiving unit receives optical signals output from a plurality of light sources at the same time, the signal quality deterioration is effectively suppressed and a higher quality optical space transmission device is provided. .

  In the tenth aspect of the invention, a plurality of diffused light sources emit light, and the phase of the modulated signal is adjusted, thereby increasing the received signal level in a predetermined area in space and flexibly corresponding to the place where the optical receiving unit is installed. Provided is a high-quality optical space transmission device that can be used.

  In the eleventh and twelfth inventions described above, even when the optical receiver receives optical signals output from a plurality of light sources simultaneously by using a light source with low coherence for the optical transmitter, the signal quality is deteriorated. Therefore, a higher quality optical space transmission device is provided.

(Embodiment 1)
The optical space transmission apparatus according to Embodiment 1 of the present invention is shown in FIG. In FIG. 1, the space optical transmission apparatus of the present embodiment includes a light emitting unit 101, an optical coupling unit 102, an optical receiving unit 103, and a light source control unit 104. The light emitting unit 101 includes a plurality of n (n = 7 in FIG. 1) point light sources 101a to 101g, and the light transmitting unit 100 includes the light emitting unit 101, the optical coupling unit 102, and the light source control unit 104. Constitute. In addition, the optical receiving unit 103 includes an optical detection unit 103a.

  Next, the operation of this embodiment shown in FIG. 1 will be described. The light source control unit 104 has n output ports corresponding to the n point light sources 101a to 101g, selects any one port according to the control signal 15, and applies a predetermined bias value to the modulation signal 14 input from the port. (Bias current) is added and output. The point light sources 101a to 101g each receive an output signal from a corresponding port among the n output ports of the light source control unit 104, and convert and output to optical signals 11a to 11g. The optical coupling unit 102 is configured by a lens or the like, and transmits the optical signals 11a to 11g to the space via the light emitting end surface 100a of the optical transmission unit 100, and the optical signals 11a to 11g irradiate on the space, respectively. The optical path is adjusted so that the regions 13a to 13g are adjacent to each other and different from each other. The optical receiving unit 103 (optical detection unit 103a) is disposed in the irradiation range 13 constituted by the irradiation regions 13a to 13g of the optical signals 11a to 11g, and inputs any one of the optical signals 11a to 11g to generate an electric signal. A signal (modulated signal) 14 ′ is converted and output.

  Here, the light source control unit 104 sequentially scans the irradiation regions 13a to 13g with the light signals 11a to 11g (for example, in FIG. 1, 13a-> 13b-> 13c-> 13d-> 13e-> 13f- > 13g-> 13a-> ...), the output signals to the point light sources 101a-101g are switched, and instantaneously, any one of the optical signals 11a-11g irradiates the irradiation region, and is long-term Specifically, the optical signals 11a to 11g are controlled so as to irradiate the irradiation range 13 thoroughly. As a result, as in FIG. 5, the optical signal is collected and high optical power is transmitted toward the irradiation area to increase the SNR of the received signal and perform high-speed transmission. Similarly, the optical signal is diffused to expand the irradiation range, and the installation accuracy of the optical receiver is relaxed. As for the transmission power from the optical transmission unit 100, the optical powers Ptotal for irradiating the predetermined range 10 with the optical signals 11a to 11g being separated from the light emitting end face 100a by the predetermined distance Dee are according to FIG. Each of the transmission rates is determined to be equal to or less than a predetermined value. As a result, the transmission rate is equivalent to that shown in FIG.

  Further, when the quality of the electrical signal 14 ′ output from the optical receiving unit 103 can be monitored, the light source control unit 104 stops scanning the optical signal in a state where the signal quality is maximized based on the monitor information. The irradiation area is fixed. This prevents a decrease in the effective transmission rate due to the scanning / switching time of the optical signal and performs faster optical space transmission. In addition, as a specific monitoring means, the structure etc. which detect SNR of a received signal, convert the said SNR value into an electric radio signal etc., and transmit to the optical transmission part 100 etc. are assumed.

  Next, another configuration relating to the present embodiment will be described with reference to FIG. FIG. 2 is a diagram in which the physical arrangement of the point light sources 101a to 101g in FIG. 1 is changed, and the light source 201 is configured by the point light sources 101a to 101g. In this configuration, the point light sources 101a to 101g receive the signal switched and output from the light source control unit 104, convert it into an optical signal, and output the same as in FIG. Here, the point light sources 101a to 101g are arranged in a concave shape with respect to the direction in which the optical signal is output. Thereby, for example, as shown in FIG. 2, the optical receiving unit 103 is installed across a plurality of optical signal irradiation regions (13b and 13c in FIG. 2), and as a result, a plurality of optical signal components (see FIG. 2). 2, even when 11b and 11c) are simultaneously input to the optical detection unit 103a, the skew (phase shift) between both optical signals is reduced, and higher-quality waveform transmission is performed.

  In the first embodiment (FIGS. 1 and 2), the point light sources 101a to 101g are illustrated in a one-dimensional (linear) arrangement, but in principle any arrangement may be used. It may be arranged two-dimensionally (planar). Further, the number n of point light sources may be any number other than seven.

  As described above, according to the first aspect of the present invention, high transmission signal quality is ensured by sequentially switching a plurality of point light sources to emit light and irradiating a predetermined range in space. However, the installation accuracy of the optical receiver can be relaxed, and a high-speed optical space transmission device can be provided with a simple configuration.

(Embodiment 2)
An optical transmission apparatus according to Embodiment 2 of the present invention will be described below with reference to FIG. 3, the optical space transmission device of the present embodiment includes a light emitting unit 101, an optical coupling unit 102, an optical receiving unit 103, a light source control unit 104, and a delay of a plurality of n (n = 7 in FIG. 3). Control units 305a to 305g are provided, and the configuration in FIG. 2 is different in that delay adjustment units 305a to 305g are newly provided. The light emitting unit 101 includes n point light sources 101a to 101g, and the light transmitting unit 101 includes the light emitting unit 101, the optical coupling unit 102, the light source control unit 104, and the delay adjustment units 305a to 305g. . In addition, the optical receiving unit 103 includes an optical detection unit 103a.

  Next, the operation of this embodiment shown in FIG. 3 will be described. Since the configuration of this embodiment conforms to that of the first embodiment (FIG. 1), the same number is assigned to the blocks performing the same operation, the description thereof is omitted, and only the differences are described below. Explained. In this configuration, in the optical transmission apparatus according to the present embodiment, the delay control units 305a to 305g are provided corresponding to the n output ports of the light source control unit 104, and each of the output signals from the corresponding ports has a predetermined delay amount. Da to Dg are assigned and output. The point light sources 101a to 101g receive the output signals from the delay adjustment units 305a to 305g, respectively, convert them into optical signals 11a to 11g, and output them.

  Here, the delay adjustment units 305 a to 305 g give a large delay amount to the input signal to the point light source located near the optical receiving unit 103, and are located far from the optical receiving unit 103. A small delay amount is given to the input signal to the point light source. Thereby, for example, as shown in FIG. 3, the optical receiving unit 103 is installed across a plurality of optical signal irradiation regions (13b and 13c in FIG. 3), and as a result, a plurality of optical signal components (FIG. 3) are installed. Then, even when 11b and 11c) are simultaneously input to the optical detection unit 103a, a delay amount larger than 101d is given to the point light source 101c to reduce the skew (phase shift) between the two optical signals, and high speed. Higher quality waveform transmission can be performed while achieving both transmission and ease of installation accuracy of the optical receiver.

  Next, another configuration relating to the present embodiment will be described with reference to FIG. 4 is obtained by changing the point light sources 101a to 101g in FIG. 3 to diffuse light sources 401a to 401g. As shown in FIG. 4, the output light signal from each point light source is diffused light, and the irradiation area is spatially So that they overlap each other. The delay control units 305a to 305g add predetermined delay amounts Da to Dg to the output signals from the corresponding ports of the light source control unit 104 and output the signals. As a result, it is possible to adjust and control a spatial region in which the optical signals overlap in phase (the optical signals strengthen each other), that is, a region where the optical signal can be efficiently received, and further change the delay amount. Thus, the reception area can be arbitrarily changed. That is, the emission direction / angle of the output light from the light emitting unit 101 is changed in a pseudo manner to set an optimum emission direction with respect to the installation position of the light receiving unit, thereby efficiently performing higher quality waveform transmission. Can do.

  In FIG. 4, the optical coupling portion is omitted, but may be inserted as appropriate as in FIGS. 1 to 3.

  As described above, according to the second aspect of the present invention, when a plurality of optical signals are input to the optical receiver by optimally setting and controlling the delay amount / phase of the input signals to the plurality of point light sources. Signal quality deterioration can be prevented, or the optical signal emission direction can be optimally controlled in accordance with the position of the optical receiver to provide a higher-speed and more flexible optical space transmission device.

  INDUSTRIAL APPLICABILITY The present invention can be used in an optical space transmission technology that performs high-speed transmission while suppressing the danger to human vision when performing wireless communication by emitting light into free space.

The block diagram which shows the structure of the optical space transmission apparatus which concerns on the 1st Embodiment of this invention. The block diagram which shows the structure of the optical space transmission apparatus which concerns on another structure of the 1st Embodiment of this invention. The block diagram which shows the structure of the optical space transmission apparatus which concerns on the 2nd Embodiment of this invention. The block diagram which shows the structure of the optical space transmission apparatus which concerns on another structure of the 2nd Embodiment of this invention. Block diagram showing the configuration of a conventional optical space transmission device The block diagram which shows another structure of the conventional optical space transmission apparatus

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Optical transmission part 101 Light emission part 102 Optical coupling part 103 Optical reception part 104 Light source control part 101a-101g Point light source 11a-11g Optical signal 14,14 'Modulation signal 15 Control signal 200 Optical transmission part 201 Light emission part 305a-305g Delay adjustment 41a to 41g Optical signal

Claims (12)

An optical transmission device comprising an optical transmitter and an optical receiver,
The optical transmitter is
A light source driver that inputs a modulation signal and a control signal, and selectively outputs the modulation signal from any one of a plurality of n (n is an integer of 2 or more) output ports according to the control signal;
A light emitting unit that is provided corresponding to n output ports of the light source driving unit, and that includes n light sources that convert the output signals into optical signals and output the optical signals, respectively.
The optical receiver is
An optical space transmission device including an optical detection unit that inputs any one of optical signals output from n light sources of the light emitting unit, converts the optical signal into an electrical signal, and outputs the electrical signal. The optical space transmission device according to claim 1, wherein the optical signal output from the optical transmitter scans a desired spatial range in a predetermined procedure for a predetermined time. The optical space according to claim 2, wherein scanning of the optical signal output from the optical transmission unit is stopped in a state where the level of the electrical signal output from the optical reception unit is maximized or in a state where the signal quality is optimal. Transmission equipment. 3. The optical space transmission device according to claim 1, wherein all of the optical signals output from the n light sources are output through the same opening provided in the optical transmission unit. The optical space transmission device according to claim 1, wherein the optical signals output from the n light sources irradiate different spatial ranges. The optical space transmission device according to claim 1, wherein the optical signals output from the n light sources irradiate spatial regions adjacent to each other. The optical space transmission device according to claim 1, wherein the n light sources are arranged adjacent to each other on the same plane. The optical space transmission device according to claim 1, wherein the n light sources are arranged adjacent to each other on a concave surface. M (m) inserted between the n output ports of the light source driver and the n light sources, and adds a predetermined delay time to all or part of the injected current output from the light source driver. The optical space transmission device according to any one of claims 1 to 6, further comprising a delay adjusting unit of n or less. An optical transmission device comprising an optical transmitter and an optical receiver,
The optical transmitter is
A light source driver that inputs a modulation signal and a control signal, and selectively outputs the modulation signal from any one of n output ports according to the control signal;
M delay adjusting units for respectively adding a predetermined delay time to all or a part of the injection current output from the n output port of the light source driving unit;
N corresponding to the n output ports of the light source driving unit, which receives an output signal or an output signal from the m delay adjusting unit, converts it into a diffused optical signal in which irradiation areas overlap each other, and outputs n A light-emitting unit comprising a diffused light source of
The optical receiver is
An optical detection unit that inputs any of the optical signals output from the n diffused light sources of the light emitting unit, converts the optical signal into an electrical signal, and outputs the electrical signal,
The delay adjustment unit adjusts the delay time so that phases of a plurality of optical signals are matched in a predetermined region within an entire irradiation range formed by irradiation regions of optical signals output from the n diffusion light sources. Optical space transmission device to be adjusted. The optical space transmission device according to claim 10, wherein the n diffused light sources are multimode light sources. The optical space transmission device according to claim 11, wherein the multimode light source is an LED (Light Emission Diode).

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