JP4389677B2 - Optical communication system and optical communication control method - Google Patents

Description

  The present invention relates to an optical communication system and an optical communication control method, and in particular, a first device including a first light receiving element, a plurality of second devices each including a second light emitting element, and a second light emission of each second device. An optical communication system including a second optical signal transmitter that transmits optical signals emitted from the elements to the first device and receives light by the first light receiving element of the first device, and is applicable to the optical communication system The present invention relates to an optical communication control method.

  Conventionally, a single layer of light that has been incident from a transmission source is configured by forming a plurality of signal light input / output portions that are responsible for the input and output of signal light in a layered waveguide that diffuses and propagates the input signal light. An optical signal transmission body (also called an optical sheet bus) capable of distributing signals to a plurality of transmission destinations and emitting (combining) a plurality of optical signals incident from a plurality of transmission sources to a single transmission destination. And an optical communication system including the optical signal transmitter has been proposed (see Patent Documents 1 to 6). When distributing or combining optical signals with strong directivity, such as laser light, the optical signal was once converted into an electrical signal, then distributed or combined, and then the distributed or combined electrical signal was converted back into an optical signal. Although a complicated configuration such as transmission is required, by using the optical signal transmitter described above, it becomes possible to distribute or combine optical signals with strong directivity as they are, thereby simplifying the configuration of the optical communication system. be able to. In addition, the optical signal transmission body can easily insert / remove an optical fiber for transmitting an optical signal, and the construction of the optical communication system and the change of the configuration are easy, as in the case of inserting / removing the signal line of the electric signal by the connector. Has the advantage.

In addition, in Patent Document 7 related to the above, when the master node sends data to the slave node, the driving current is supplied from the current control circuit corresponding to the slave node to the light emitting element of the corresponding optical communication interface to turn on / off the light. When the response data is not obtained from the slave node, the drive current is increased stepwise until the reply data is obtained, and the second current from the current control circuit is sent when the slave node sends data to the master node. A technique is disclosed in which turning on / off control of the second light-emitting element is performed with the drive current, and when the return data is not obtained from the master node, the drive current is increased stepwise until the reply data is obtained.
Japanese Patent Laid-Open No. 9-270751 Japanese Patent Laid-Open No. 9-270752 Japanese Patent Laid-Open No. 10-65625 Japanese Patent Laid-Open No. 11-39069 JP-A-11-39251 JP-A-11-205246 JP-A-8-102715

  By the way, when the above optical signal transmission body is provided in an optical communication system, the construction and the configuration change of the optical communication system can be easily performed, but the devices that perform optical communication with each other are connected via the optical signal transmission body. There is a possibility that the optical attenuation amount of the optical signal in each of a plurality of optical transmission paths to be connected is greatly different (particularly POF (Plastic Optical Fiber) which is frequently used for transmission of optical signals over a short distance with a large optical attenuation amount). The possibility is high in an optical transmission line formed using an optical fiber. For this reason, in order to keep the bit error rate (BER) below the required level, the optimum light emission intensity of the light emitting element corresponding to the amount of light attenuation is obtained for each optical transmission line, and the light emitting element at the time of optical signal transmission It is desirable to optimize the amount of received light in the light receiving element that receives the optical signal by adjusting the emitted light intensity to the optimum luminous intensity corresponding to the optical transmission path through which the transmitted optical signal is transmitted.

  On the other hand, if a light receiving element that receives an optical signal continues to receive no optical signal or continues to receive a certain level of optical signal, the responsiveness deteriorates. For this reason, the light emitting element emits light, and the high response of the light receiving element is maintained by continuing to provide the light receiving element with an optical signal having a change in level intensity and without a bias in duty ratio (so-called DC balanced). It is preferable to do. However, there is a problem in that the lifetime of the light emitting element is shortened if the light emitting element is continuously turned on in order to maintain the high responsiveness of the light receiving element.

  The present invention has been made in consideration of the above-described facts, and an object thereof is to obtain an optical communication system and an optical communication control method capable of realizing a long life of a light emitting element without causing deterioration of responsiveness of the light receiving element. is there.

In order to achieve the above object, an optical communication system according to a first aspect of the present invention includes a first device including a first light emitting element and a first light receiving element, and a second light emitting element and a second light receiving element , respectively. A plurality of second devices, and optical signals modulated in accordance with arbitrary information and emitted from the first light emitting elements of the first device, respectively, to the plurality of second devices, and the plurality of second devices A first optical signal transmission body that receives light by each of the second light receiving elements, and an optical signal that is modulated in accordance with arbitrary information and emitted from the second light emitting elements of the plurality of second devices. 1 is transmitted to the device, a first device optical communication system and a second optical signal transmission medium to be received by the first light receiving element, respectively provided in the plurality of second devices, the corresponding Causing the second light emitting element of the second device to emit light, and the first device When light reception state information representing a light reception state by the first light receiving element is received from the first device and the received light reception state information is different from an optimal value for receiving an optical signal, by then changing the emission intensity of the second light emitting element repeated thereby emitting the second light emitting element, the light emission intensity of the second light emitting element of the corresponding second device and the optimization means for optimizing, Optimized by the optimization means provided in the first device or provided in one second device having a function of transmitting / receiving information to / from another second device via the first device. Based on the light emission intensity of the second light emitting element of each of the plurality of second devices after the conversion has been performed in all the second devices, the single light emitting element having the smallest light emission intensity of the second light emitting element. Setting means for setting two devices as a specific second device; When the information is not transmitted from each of the plurality of second devices to the first device, the second light emitting element is caused to emit light, and the first light receiving element of the first device has a predetermined value. A predetermined process for receiving an optical signal is executed by the specific second device .

An optical communication system according to an invention of claim 1 includes a first device including a first light emitting element and a first light receiving element, a plurality of second devices each including a second light emitting element and a second light receiving element , A first optical signal modulated in accordance with arbitrary information and emitted from the first light emitting element of the first device to each of the plurality of second devices and received by the second light receiving elements of the plurality of second devices. Optical signal transmitters and optical signals modulated in accordance with arbitrary information and emitted from the second light emitting elements of the plurality of second devices are transmitted to the first device, respectively, and the first light receiving elements of the first device A second optical signal transmission body for receiving light is provided. In the above configuration, the optical signals emitted from the second light emitting elements of the individual second devices are transmitted through the optical transmission lines that include the second optical signal transmission body and part of them are different from each other. Since the light is received by one light receiving element, there is a possibility that the optical attenuation amounts in the individual optical transmission paths through which the optical signals emitted from the second light emitting elements of the individual second devices are transmitted are also different from each other. is there.

On the other hand , according to the first aspect of the present invention, the light receiving device that is provided in each of the plurality of second devices , causes the second light emitting element of the corresponding second device to emit light, and represents the light receiving state by the first light receiving element of the first device. When the state information is received from the first device and the received light reception state information indicates that it is different from the optimum value for receiving the optical signal, the light emission intensity of the second light emitting element is changed to change the second light emitting element. by repeating the causing the light emitting element, the light emission intensity of the corresponding second light emitting element of the second device is provided with optimizing means to optimize, second optimization by the optimization means all Even when the optical signal emitted from the second light emitting element of each second device is different in the optical attenuation amount in the optical transmission path through which the optical signal is transmitted, best received to receive optical signals by the first light receiving element Would be respectively received in the state, it is possible to suppress an increase in the BER (bit error rate) in the transmission of the optical signal from each second device to the first device.

On the other hand, in the optical communication system according to the first aspect of the present invention, the optical signals emitted from the second light emitting elements of the individual second devices are respectively received by the first light receiving elements of the first device. In order to avoid the deterioration of the response of the first light receiving element provided in the first light emitting element, the second light emitting element emits light when information is not transmitted from each of the plurality of second devices to the first device. the predetermined processing to receive the predetermined optical signal to the first light receiving element of the first device by, it Re is performed by any of the plurality of second devices. However, since the light emission time of the second light emitting element is increased in the second device that performs the predetermined processing, the lifetime of the second light emitting element is extremely reduced, and the second light emitting element must be replaced frequently. There is a possibility of not getting.

On the other hand, in the invention described in claim 1, the lifetime of the light emitting element is determined by the product of the light emission intensity and the light emission time (total light emission time) of the light emitting element. Based on the light emission intensity of the second light emitting element of each of the plurality of second devices after being performed in all the second devices, a single second device having the minimum light emission intensity of the second light emitting element is identified as the second Setting means for setting as a device is provided in the first device or one second device having a function of transmitting / receiving information to / from another second device via the first device, and each of the plurality of second devices When the information is not transmitted from the first device to the first device, the second light emitting element is caused to emit light and the first light receiving element of the first device receives a predetermined light signal, and a predetermined second process is performed. It is executed by the device. As a result, the product of the light emission intensity and the light emission time of the second light emitting elements of the individual second devices, that is, the lifetime is averaged, so that only the second light emitting elements of some of the second devices are extremely reduced. Can be prevented. Therefore, according to the first aspect of the present invention, the length of the light emitting element (the second light emitting element of the individual second device) can be reduced without deteriorating the response of the light receiving element (the first light receiving element of the first device). Life expectancy can be realized.

An optical communication system according to a second aspect of the invention includes a first device including a first light emitting element and a first light receiving element, a plurality of second devices each including a second light emitting element and a second light receiving element, Optical signals modulated according to arbitrary information and emitted from the first light emitting elements of the first device are transmitted to the plurality of second devices, respectively, and the second light receiving elements of the plurality of second devices are used. A first optical signal transmission body for receiving light; and an optical signal modulated in accordance with arbitrary information and emitted from the second light emitting elements of the plurality of second devices to each of the first devices; An optical communication system comprising: a second optical signal transmission body for receiving light by the first light receiving element of the first device, wherein the second communication device is provided in each of the plurality of second devices, The second light emitting element is caused to emit light, and the first light receiving element of the first device is used. When light reception state information representing a light state is received from the first device, and the received light reception state information indicates that it is different from an optimum value for receiving an optical signal, light emission of the second light emitting element Optimized means for optimizing the light emission intensity of the second light emitting element of the corresponding second device by repeatedly changing the intensity and causing the second light emitting element to emit light, and provided in the first device Or provided in one second device having a function of transmitting / receiving information to / from another second device via the first device, and the optimization by the optimization means is performed for all the second devices. The plurality of second devices selected in ascending order of the light emission intensity of the second light emitting elements based on the light emission intensity of the second light emitting elements of each of the plurality of second devices after being performed in the device Setting means for setting as two devices, A predetermined light signal that causes the first light receiving element of the first device to receive light when the information is not transmitted from each of the two devices to the first device. So that the second device that executes the predetermined processing is circulated among the plurality of specific second devices. The second device for executing the predetermined process is switched every time a predetermined time elapses.

An optical communication system according to a second aspect of the invention includes a first device, a plurality of second devices, a first optical signal transmission body, and a second optical signal transmission body, as in the first aspect of the invention. ing. Further, the invention according to claim 2 is provided in each of the plurality of second devices, and causes the second light emitting element of the corresponding second device to emit light, similarly to the invention according to claim 1, and the first of the first device. When light reception state information indicating a light reception state by the light receiving element is received from the first device and the received light reception state information indicates that the received light state information is different from an optimum value for receiving an optical signal, Optimizing means for optimizing the light emission intensity of the second light emitting element of the corresponding second device by repeatedly changing the light emission intensity and causing the second light emitting element to emit light is provided.

According to the second aspect of the present invention, the second light emitting element is based on the light emission intensity of the second light emitting element of each of the plurality of second devices after the optimization by the optimization unit is performed in all the second devices. A setting means for setting a plurality of second devices selected in ascending order of emission intensity as a specific second device has a function of transmitting / receiving information to / from another second device via the first device or the first device. First light reception of the first device by causing the second light emitting element to emit light when information is not transmitted from each of the plurality of second devices to the first device. A predetermined process for causing the element to receive a predetermined optical signal is executed by one second apparatus among the plurality of specific second apparatuses, and the second apparatus for executing the predetermined process is the plurality of specific second apparatuses. Second device that executes a predetermined process every time a predetermined time elapses so as to circulate in It is switched. Thereby, even when there are a plurality of second devices having the minimum light emission intensity of the second light emitting element, or when the light emission intensity of the second light emitting element of each second device is approximate, etc. , it is possible to reduce the difference of the product of the emission intensity and the light emission time of the second light-emitting elements in each of the second apparatus, it is possible to average the lifetime of the second light emitting element of each of the second apparatus.

Incidentally, in the invention of claim 2, the course of the upper Symbol predetermined time, for example, an optical communication system according to the present invention, from the first device to the respective second device, for example a first device and a plurality of second apparatus If the configuration is such that an optical signal such as a frame clock or other arbitrary serial signal is transmitted, it is detected by counting the pulses of this optical signal (either rising edge or falling edge). can do. Also, the lapse of the predetermined time may be detected by counting the pulse of the optical signals, such as any serial signal transmitted from the second device to the first device, CPU and other functioning as a setting unit It is also possible to detect by measuring the elapsed time by the CPU.

The predetermined time in the second aspect of the present invention (the time each of the plurality of particular second apparatus is performing a predetermined processing) is always may be constant, but the second of the plurality of specific second device When the light emission intensity of the light emitting elements is different, for example, as described in claim 3 , the product of the light emission intensity and the light emission time of the second light emitting element of each second device is made uniform. The predetermined time is set for each of the plurality of specific second devices according to the difference in the emission intensity of the second light emitting element in each of the plurality of specific second devices , and the predetermined processing is executed. It is preferable to switch the second device that executes a predetermined process each time a predetermined time corresponding to two devices elapses . As a result, the product of the light emission intensity and the light emission time of the second light emitting elements of the individual second devices can be made more uniform, and the lifetime of the second light emitting elements of the individual second devices can be more accurately averaged. be able to.

Furthermore, in the invention described in claim 3, while the process of switching the second device for executing the predetermined process is being performed, it is considered that the second device related to the switch cannot perform normal communication. It is done. Considering this, for example, as described in claim 4, the first device from the second device until the end of the processing after the execution of the processing for switching the second device for executing the predetermined processing is started. It is preferable to provide prohibition control means for prohibiting communication with the apparatus. As a result, when the first device tries to communicate with the second device that cannot perform normal communication, the traffic of the optical communication system increases unnecessarily, or the load on the first device is wasted. The increase can be prevented.

An optical communication control method according to a fifth aspect of the present invention includes a first device including a first light emitting element and a first light receiving element, and a plurality of second devices each including a second light emitting element and a second light receiving element. The optical signals modulated according to arbitrary information and emitted from the first light emitting elements of the first device are transmitted to the plurality of second devices, respectively, and the second light receiving elements of the plurality of second devices are transmitted. A first optical signal transmitter that receives each of the optical signals, and an optical signal that is modulated according to arbitrary information and emitted from the second light emitting elements of the plurality of second devices, respectively, to the first device, In an optical communication system comprising: a second optical signal transmission body that receives light by the first light receiving element of the first device; and causing the second light emitting element of one second device to emit light, and the first device The amount of light received by the first light receiving element is the optimum value and phase for receiving the optical signal. In this case, by changing the light emission intensity of the second light emitting element of the one second device and repeating the light emission of the second light emitting element of the one second device, the one first device Optimize the light emission intensity of the second light emitting element of the two devices for each of the plurality of second devices, and perform the optimization on all the second devices. Based on the light emission intensity of each of the second light emitting elements, a single second device having the minimum light emission intensity of the second light emitting element is set as a specific second device, and each of the plurality of second devices is A predetermined process of causing the second light emitting element to emit light and causing the first light receiving element of the first apparatus to receive a predetermined optical signal when transmission of information to the first apparatus is not performed; It is characterized by being executed by a specific second device , It is possible to realize a long life of the light emitting device without being in the same manner as the invention of claim 1, wherein, resulting deterioration in responsiveness of the light receiving element.

An optical communication control method according to a sixth aspect of the invention includes a first device including a first light emitting element and a first light receiving element, and a plurality of second devices each including a second light emitting element and a second light receiving element. The optical signals modulated according to arbitrary information and emitted from the first light emitting elements of the first device are transmitted to the plurality of second devices, respectively, and the second light receiving elements of the plurality of second devices are transmitted. A first optical signal transmitter that receives each of the optical signals, and an optical signal that is modulated according to arbitrary information and emitted from the second light emitting elements of the plurality of second devices, respectively, to the first device, In an optical communication system comprising: a second optical signal transmission body that receives light by the first light receiving element of the first device; and causing the second light emitting element of one second device to emit light, and the first device The amount of light received by the first light receiving element is the optimum value and phase for receiving the optical signal. In this case, by changing the light emission intensity of the second light emitting element of the one second device and repeating the light emission of the second light emitting element of the one second device, the one first device Optimize the light emission intensity of the second light emitting element of the two devices for each of the plurality of second devices, and perform the optimization on all the second devices. Based on the light emission intensity of each of the second light emitting elements, the plurality of second devices selected in ascending order of the light emission intensity of the second light emitting elements are set as specific second devices, and each of the plurality of second devices is set. A predetermined process of causing the second light emitting element to emit light and causing the first light receiving element of the first device to receive a predetermined optical signal when information is not transmitted from the first device to the first device; Realized by one second device among the plurality of specific second devices. And switching the second device that executes the predetermined process every time a predetermined time elapses so that the second device that executes the predetermined process circulates among the plurality of specific second devices. Since it is a feature, the lifetime of the light emitting element can be extended without causing deterioration of the response of the light receiving element, as in the invention of claim 2 .

As described above, in the present invention, the first device, the plurality of second devices , and the first light receiving elements of the plurality of second devices receive the light signals emitted from the first light emitting elements of the first device, respectively. And an optical communication system including a second optical signal transmitter that receives light signals emitted from the second light emitting elements of the plurality of second devices by the first light receiving elements of the first device, respectively. When the second light emitting element of one second device emits light and the amount of light received by the first light receiving element of the first device is different from the optimum value for receiving an optical signal, Optimizing the light emission intensity of the second light emitting element of one second device by repeatedly changing the light emission intensity of the second light emitting element of the device and causing the second light emitting element of one second device to emit light Is performed for each of the plurality of second devices, and the optimization is performed on all the second devices. Based on the light emission intensity of each second light emitting element of the plurality of second devices, a single second device having the minimum light emission intensity of the second light emitting element is set as the specific second device, and A predetermined process for causing the first light receiving element of the first device to receive a predetermined optical signal by causing the second light emitting element to emit light when information is not transmitted from the respective devices to the first device. Since it is executed by the two devices, it has an excellent effect that it is possible to extend the life of the light emitting element without deteriorating the response of the light receiving element.
The present invention also provides a first optical signal transmission in which optical signals emitted from the first device, the plurality of second devices, and the first light emitting elements of the first device are respectively received by the second light receiving elements of the plurality of second devices. And an optical communication system comprising a second optical signal transmission body for receiving optical signals emitted from the second light emitting elements of the plurality of second devices by the first light receiving elements of the first device, respectively. When the second light emitting element of the second device emits light and the amount of light received by the first light receiving element of the first device is different from the optimum value for receiving an optical signal, the second of one second device It is possible to optimize the light emission intensity of the second light emitting element of one second device by changing the light emission intensity of the light emitting element and repeating the light emission of the second light emitting element of one second device. A plurality of second devices after performing each of the second devices and performing the optimization on all the second devices Based on the light emission intensity of each second light emitting element, a plurality of second devices selected in ascending order of the light emission intensity of the second light emitting elements are set as specific second devices, and each of the plurality of second devices starts with the first device. When the transmission of information to the device is not performed, a predetermined process of causing the first light receiving element of the first device to emit light and receiving the predetermined optical signal is performed by a plurality of specific second devices. A second process that is executed by one second device and that executes a predetermined process every time a predetermined time elapses so that the second device that executes the predetermined process circulates among a plurality of specific second devices. Since the two devices are switched, there is an excellent effect that the life of the light emitting element can be extended without causing deterioration of the response of the light receiving element.

  Hereinafter, an example of an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 shows an electronic device 10 to which the present invention is applied. The electronic device 10 includes a plurality of electronic circuits 12A, 12B, 12C, and 12D. Of the electronic circuits 12A to 12D, the electronic circuit 12A functions as a master that controls the operation of the other electronic circuits 12B to 12D, and the electronic circuits 12B to 12D function as slaves that operate under the control of the electronic circuit 12A.

  Although any device can be applied as the electronic device 10, in this embodiment, image data is received via a network such as a LAN, and image processing such as screen processing is performed based on the received image data. To generate image data for exposure for each color component (for example, C (cyan), M (magenta), Y (yellow), K (black), S1 (special color 1), S2 (special color 2), etc.) An electrostatic latent image of each color component is formed by controlling image exposure by a ROS (Raster Output Scanner) provided for each color component based on the exposed image data, and the electrostatic latent image of each color component thus formed is formed. This is applied to a full color printer configured to form a full color toner image by developing with each color component developer and superimposing them, and transferring and fixing the formed full color toner image onto a recording sheet. In the electronic circuits 12B to 12D functioning as slaves, the electronic circuit 12B generates C and M, the electronic circuit 12C generates Y and K, the electronic circuit 12D generates exposure image data for each color component S1 and S2, and the image by ROS. The electronic circuit 12A configured by an image processing circuit for controlling exposure and functioning as a master includes a control circuit (for example, peripheral devices such as a CPU and a memory) for controlling the operation of each image processing circuit (electronic circuits 12B to 12D). The control circuit is configured.

  In this embodiment, communication between the electronic circuit 12A and the electronic circuits 12B to 12D is performed by optical communication, and optical communication between these electronic circuits is realized between the electronic circuit 12A and the electronic circuits 12B to 12D. An optical communication system 14 is provided. The optical communication system 14 includes optical communication interface (I / F) units 16A to 16D connected to the individual electronic circuits 12A to 12D. The optical communication I / F units 16A to 16D are respectively mounted on the same substrate as the connected electronic circuits 12A to 12D. The optical communication I / F units 16A to 16D have substantially the same configuration, and a plurality of (for example, five) LD (laser diode) LD arrays 18 arranged in a line and a plurality of (for example, five) There are provided a PD array 20 in which a plurality of PDs (photodiodes) are arranged in a line, and an optical communication control unit 22 connected to the electronic circuit 12, the LD array 18 and the PD array 20, respectively.

  Each of the LD array 18 and the PD array 20 of each optical communication I / F unit 16 is configured so that the optical connector 24 can be freely attached and detached, and the optical connector 24 connected to the LD array 18 of the optical communication I / F unit 16A. One end of the first optical fiber 26 is attached, and one end of the first optical fiber 28 is attached to the optical connector 24 attached to the PD array 20, and is connected to the LD array 18 of the optical communication I / F unit 16B. One end of the second optical fiber 36 is attached to the optical connector 24, and one end of the second optical fiber 30 is attached to the optical connector 24 attached to the PD array 20. Similarly, one end of the second optical fiber 38 is connected to the optical connector 24 connected to the LD array 18 of the optical communication I / F unit 16C, and the second optical fiber 32 is connected to the optical connector 24 connected to the PD array 20. One end of the second optical fiber 40 is connected to the optical connector 24 connected to the LD array 18 of the optical communication I / F unit 16D, and the second end is connected to the optical connector 24 connected to the PD array 20. One end of the optical fiber 34 is attached.

  The first optical fibers 26, 28 and the second optical fibers 30, 32, 34, 36, 38, 40 are optical fibers made of synthetic resin called POF (Plastic Optical Fiber) (the core material is acrylic, and the cladding covers the core material) An optical fiber whose material is made of fluororesin is bundled by the same number (for example, five) as the number of LDs in the LD array 18 and the number of PDs in the PD array 20. As shown in FIG. 2, optical connectors 24 are respectively attached to the other ends of the first optical fiber 26 and the second optical fibers 30, 32, and 34, and these optical connectors 24 are connected to the first optical sheet bus 42A. Each is connected. Although not shown in detail, optical connectors 24 are attached to the other ends of the first optical fiber 28 and the second optical fibers 36, 38, 40, respectively. These optical connectors 24 are connected to the second optical sheet bus. 42B, respectively.

  The optical sheet buses 42A and 42B are configured by embedding a waveguide member 44 shown in FIGS. 3A and 4A in the same number as the number of optical fibers (for example, five) in a synthetic resin base member. Has been. The waveguide member 44 is made of a material having a high light transmittance and a refractive index higher than that of a clad layer to be described later (for example, polymethylmethacrylate). The waveguide member 44 has an elongated rectangular shape as a whole, and the width dimension changes in a stepped manner. The stepped portions 46A and 46B are formed at two locations in the middle portion. Inclinations that are inclined at an angle of 45 ° with respect to the longitudinal direction and the vertical direction of the waveguide member 44 (vertical direction in FIG. 3) at both ends of the waveguide member 44 and the stepped portions 46A and 46B. Surfaces 44A to 44D are respectively formed. The inclined surfaces 44A to 44D function as signal light incident / exit portions. The waveguide member 44 is embedded so that portions of the upper surface of the waveguide member 44 corresponding to the individual inclined surfaces 44 </ b> A to 44 </ b> D are exposed from the upper surface of the base member. Of these, the base member is connected to face the exposed portion. The waveguide member 44 is covered with a clad layer whose outer surface other than the portion exposed from the upper surface of the base member is made of a material having a refractive index lower than that of the material constituting the waveguide member 44 (for example, a fluorine polymer). Has been.

  In the first optical sheet bus 42A, the optical connector 24 to which the first optical fiber 26 is attached has an exposed portion corresponding to an inclined surface 44A formed in a portion having the largest width dimension among the individual waveguide members 44. The optical connector 24 to which the second optical fibers 30, 32, and 34 are attached is connected to the base member so as to face each other, and is connected to the base member so as to face the exposed portion corresponding to the inclined surfaces 44B to 44D. . Since the first optical fiber 26 is connected to the LD array 18 of the optical communication I / F unit 16A via the optical connector 24, when the LD array 18 of the optical communication I / F unit 16A emits light, The signal light (laser light) emitted from the LD is transmitted through the first optical fiber 26, is incident on the waveguide member 44, is reflected by the inclined surface 44A, and is confined in the waveguide member 44. It diffuses and propagates in the waveguide member 44. 3B, the light is emitted from the waveguide member 44 by being reflected by the inclined surfaces 44B to 44D, and transmitted through the optical connectors 24 through the second optical fibers 30, 32, and 34. The light is received by the PD arrays 20 of the optical communication I / F units 16B to 16D.

  In the second optical sheet bus 42B, the optical connector 24 to which the first optical fiber 28 is attached is connected to the base member so as to face the exposed portion corresponding to the inclined surface 44A, and the second optical fibers 36 and 38 are connected. , 40 are connected to the base member so as to face the exposed portions corresponding to the inclined surfaces 44B to 44D. Since the second optical fibers 36, 38, and 40 are connected to the LD array 18 of the optical communication I / F units 16B to 16D via the optical connector 24, any one of the LDs of the optical communication I / F units 16B to 16D. When the array 18 emits light, the signal light (laser light) emitted from the individual LDs of the LD array 18 is transmitted through one of the second optical fibers 36, 38, and 40 and is incident on the waveguide member 44. It is diffused and propagated in the waveguide member 44 in a state of being confined in the waveguide member 44 by being reflected by any of the surfaces 44B to 44D. 4B, the light is reflected from the inclined surface 44A, is emitted from the waveguide member 44, is transmitted through the first optical fiber 28 via the optical connector 24, and the optical communication I / F. Light is received by the PD array 20 of the section 16A.

  As described above, the LD array 18 of the optical communication I / F unit 16A includes the optical communication I / F unit via the first optical fiber 26, the first optical sheet bus 42A, and the second optical fibers 30, 32, and 34. Each of the LD arrays 18 of the optical communication I / F units 16B to 16D is optically coupled to the PD arrays 20 of 16B to 16D. The second optical fibers 36, 38, and 40, the second optical sheet bus 42B, and The first optical fiber 28 is optically coupled to the PD array 20 of the optical communication I / F unit 16A. In this embodiment, the distance of the optical transmission path between the optical communication I / F unit 16A and the optical communication I / F units 16B to 16D is about 5 m.

  Next, the configuration of the optical communication control unit 22 provided in each of the optical communication I / F units 16A to 16D will be described with reference to FIG. The optical communication control unit 22 includes an electronic circuit I / F unit 50 that is connected to the electronic circuit 12 and manages communication with the electronic circuit 12. The electronic circuit I / F unit 50 incorporates information holding means including a latch or the like, receives information to be transmitted to the other electronic circuit 12 from the electronic circuit 12, and electronically receives information received from the other electronic circuit 12. A chip having a function of transmitting to the circuit 12 is provided. In the present embodiment, the electronic circuits 12B to 12D functioning as slaves are each equipped with two image processing circuits for generating image data for exposure and controlling image exposure by ROS for each single color component. Configured. For this reason, in the electronic circuit I / F unit 50 of the optical communication I / F units 16A to 16D connected to the electronic circuits 12B to 12D, two chips are provided corresponding to each image processing circuit. Each of the six chips provided in the electronic circuit I / F unit 50 of each of the optical communication I / F units 16A to 16D is assigned an ID for identifying each chip. .

  A transmission control unit 52 is connected to the electronic circuit I / F unit 50, and information received by the electronic circuit I / F unit 50 from the electronic circuit 12 (transmission information to be transmitted to other electronic circuits 12) is transmission controlled. Is output to the unit 52. The transmission control unit 52 includes a nonvolatile NVM memory 54 composed of a flash memory or the like. In the present embodiment, the NVM memory 54 of the optical communication I / F unit 16A connected to the electronic circuit 12A functioning as a master has optical communication I connected to the individual electronic circuits 12B to 12D functioning as slaves. The number of / F units 16B to 16D, the ID set in advance for the optical communication I / F units 16B to 16D, and the IDs of a total of six chips mounted on the optical communication I / F units 16B to 16D It is stored in advance, and the NVM memory 54 of the optical communication I / F units 16B to 16D stores in advance the ID of itself and the IDs of two chips mounted on itself. The information stored in the NVM memory 54 of the optical communication I / F units 16A to 16D is, for example, an electronic circuit 12 that functions as a slave in accordance with a configuration change of the electronic device 10 such as an expansion of the electronic circuit 12 that functions as a slave. When there is an increase or decrease in the number of optical communication I / F units 16 connected to, for example, it is rewritten by an operator or the like.

  An 8B / 10B encoder 56 is connected to the transmission controller 52, and transmission information is output from the transmission controller 52 to the 8B / 10B encoder 56 byte by byte. Each PD in the PD array 20 has a characteristic that the responsiveness deteriorates when the state where light is not received continues or when the state where light of a certain amount of light is received continues. The optical communication system 14 according to the present embodiment transmits transmission information serially by an optical signal, but normal data is data in which all bits are 0 or 1 (the LD is not at all while transmitting all bits of data). Data that does not emit light or the LD continues to emit light) may be included, so that while such data is transmitted serially, the PD on the receiving side becomes inactive and becomes responsive. May get worse. For this reason, the 8B / 10B encoder 56 is configured so that the ratio of 0 bits and 1 bits included in all bits of the transmission information input by 1 byte (8 bits) from the transmission control unit 52 does not fall below a certain value. The 8-bit transmission information is converted into 10-bit transmission information balanced in DC according to the conversion conditions set in advance. Note that a plurality of 8B / 10B encoders 56 are actually provided, and conversion from 8-bit transmission information to 10-bit transmission information is performed in parallel by the individual 8B / 10B encoders 56.

  The 8B / 10B encoder 56 is connected to the LD drive unit 62 via a P / S (parallel / serial) conversion unit 60, and the 10-bit transmission information converted by the 8B / 10B encoder 56 is converted to P / S. After being input to the unit 60 and converted into serial data, it is input to the LD driving unit 62. Further, an ECC (Error-Correcting Code) generation unit 58 is connected to the 8B / 10B encoder 56, and the 10-bit transmission information output from the 8B / 10B encoder 56 is also input to the ECC generation unit 58. An error correction code for error correction is generated by the generation unit 58. The ECC generation unit 58 is also connected to the LD drive unit 62 via the P / S conversion unit 60, and the error correction code generated by the ECC generation unit 58 is converted into serial data by the P / S conversion unit 60. After that, the signal is input to the LD driving unit 62. Then, the LD drive unit 62 responds to the transmission information input from the 8B / 10B encoder 56 via the P / S conversion unit 60 and the error correction code input from the ECC generation unit 58 via the P / S conversion unit 60. The transmission information is transmitted as an optical signal by controlling turning on / off of each LD in the LD array 18.

  The LD driving unit 62 is connected to the transmission control unit 52, and a clock signal and light emission intensity control information are input from the transmission control unit 52. The optical communication I / F unit 16 operates using this clock signal as a reference timing, and the LD driving unit 62 turns on and off individual LDs in the LD array 18 at a timing synchronized with the input clock signal. Further, a specific LD in the LD array 18 of the optical communication I / F unit 16A is used for transmitting a clock signal, and the LD driving unit 62 of the optical communication I / F unit 16A is specified according to the input clock signal. By controlling turning on / off of the LD, an optical signal representing a clock signal is also transmitted to the optical communication I / F units 16B to 16D. Further, the LD driving unit 62 can control the light emission intensity of each LD of the LD array 18 and controls the light emission intensity of each LD according to the input light intensity control information.

  On the other hand, a signal processing unit 64 is connected to the PD array 20, and each PD in the PD array 20 receives (receives) an optical signal, so that an output signal from each PD is amplified by the signal processing unit 64. , Demodulated into digital reception information and output. The signal processing unit 64 is connected to the error correction unit 70 via an S / P (serial / parallel) conversion unit 66, and serial reception information output from the signal processing unit 64 is parallelized by the S / P conversion unit 66. After being converted into the received information, it is input to the error correction unit 70. The signal processing unit 64 is connected to the error detection unit 68 via the S / P conversion unit 66. The error detection unit 68 generates an error (error) such as garbled bits in the reception information body based on the error collection code included in the parallel reception information input from the signal processing unit 64 via the S / P conversion unit 66. Verify whether or not. The error correction unit 70 is connected to the error detection unit 68, and performs error correction on the reception information body when the error detection unit 68 detects that an error has occurred in the reception information body.

  The error correction unit 70 is connected to the reception control unit 74 via the 8B / 10B decoder 72, and the reception information (main body) output from the error correction unit 70 after error correction is 10 bits by the 8B / 10B decoder 72. The data is converted into normal 8-bit data in units and input to the reception control unit 74. The signal processing unit 64 of the optical communication I / F units 16B to 16D is connected to the reception control unit 74, and the clock signal among the optical signals received from the optical communication I / F unit 16A is sent to the reception control unit 74. An internal clock signal that is directly input and whose phase is adjusted so as to produce a phase difference set by a synchronization timing setting process to be described later with respect to the timing of the clock signal is generated, and this internal clock signal is generated as an optical communication I / F. Used as a reference for processing timing in the units 16B to 16D. The reception control unit 74 is connected to each of the electronic circuit I / F unit 50 and the transmission control unit 52, and outputs the received reception information to the transmission control unit 52 and also electronically via the electronic circuit I / F unit 50. Output to the circuit 12. The signal processing unit 64 is also connected to the transmission control unit 52, and outputs received light amount information representing the received light amount of the optical signal to the transmission control unit 52 at the time of optical signal reception (light reception).

The optical communication I / F unit 16A corresponds to each of the first devices according to the present invention, and each LD of the LD array 18 of the optical communication I / F unit 16A is connected to the first light emitting element according to the present invention. Each PD in the PD array 20 of the communication I / F unit 16A corresponds to the first light receiving element according to the present invention. The optical communication I / F units 16B to 16D correspond to the second device according to the present invention, and each LD of the LD array 18 of the optical communication I / F units 16B to 16D is a second light emitting element according to the present invention. In addition, each PD in the PD array 20 of the optical communication I / F units 16B to 16D corresponds to the second light receiving element according to the present invention .

  Next, the operation of this embodiment will be described. In the present embodiment, when the electronic device 10 is powered on, the initialization process is performed by the optical communication control unit 22 (the transmission control unit 52) of the optical communication I / F unit 16A connected to the electronic circuit 12A functioning as a master (see FIG. 6) is executed. The transmission control unit 52 starts measuring the elapsed time from the end of execution when the initialization process is completed, and also when the elapsed time from the previous execution of the initialization process reaches a predetermined time. Perform initialization processing. In the following, the optical communication I / F unit 16A is simply referred to as “master”, and the optical communication I / F units 16B to 16D connected to the individual electronic circuits 12 functioning as slaves are simply referred to as “slave”.

  In this initialization process, first, in step 100, the NVM memory 54 is referred to, and after recognizing the number of slaves, the ID of each slave, and the ID of each chip mounted on each slave, the master and each slave are identified. In order to synchronize, synchronization that detects the optimal phase difference of the internal clock signal of each slave based on the clock signal received by each slave by transmitting from the master and sets the detected phase difference to each slave Perform timing setting processing. By this synchronization timing setting process, the master and each slave are synchronized based on the clock signal transmitted from the master to each slave. In the next step 102, an optimum emission intensity detection process is performed in which the optimum emission intensity of the master LD array 18 when information is transmitted to each slave by optical communication is sequentially detected for each slave. The detection of the optimum light emission intensity for a single slave (slave to be detected) is performed as follows.

  That is, first, assert / negate control information for asserting a specific chip (one of two chips) provided in the slave to be detected is set to the 8B / 10B encoder 56, the ECC generation unit 58, The data is output to the LD driving unit 62 via the P / S conversion unit 60, and the LD driving unit 62 is controlled so that each LD of the LD array 18 emits light with a predetermined light emission intensity. As a result, each LD of the master LD array 18 is turned on / off according to the assert / negate control information so that the light emission intensity at the time of lighting (light emission) matches a predetermined light emission intensity. The optical signal modulated according to the information is emitted from the master LD array 18 and transmitted through the first optical fiber 26, the first optical sheet bus 42A, and the second optical fibers 30, 32, 34, and then the PD of each slave. Each light is received by the array 20. Each slave refers to the received assert / negate control information to determine whether or not the information is for the chip provided in its own device. In the affirmative slave (detected slave), the designated chip is switched to the asserted state. As a result, only a specific chip of the slave to be detected is asserted.

  Subsequently, the master transmission control unit 52 uses the 8B / 10B encoder 56, the ECC generation unit 58, and the P / S conversion as information for detecting the intensity used when each LD of the LD array 18 emits light for detecting the optimum emission intensity. The output to the LD driving unit 62 via the unit 60, and the LD driving unit 62 is controlled so that each LD of the LD array 18 emits light with a predetermined emission intensity. As a result, each LD of the master LD array 18 is turned on / off according to the intensity detection information so that the emission intensity at the time of lighting (light emission) matches the predetermined emission intensity. The optical signal modulated accordingly is emitted from the master LD array 18, and the optical signal is received by each slave PD array 20.

  In each slave, when the PD array 20 receives an optical signal, the received optical signal is demodulated as reception information, and passes through an S / P conversion unit 66, an error detection unit 68, an error correction unit 70, and an 8B / 10B decoder 72. To the reception control unit 74. Then, when the reception information is input from the reception control unit 74 to the transmission control unit 52, the transmission control unit 52 executes the optical signal reception process (see FIG. 9). In this optical signal reception process, first, in step 180, it is determined whether any chip of the own device is in an asserted state, thereby determining whether the received information is information addressed to the own device. When determination is denied, it transfers to step 204 and it is determined whether the own apparatus is set to the main slave. Since the main slave is not set at this time, the above determination is denied, and the optical signal reception process is terminated without performing any process.

  If the determination in step 180 is affirmative (if any chip of the own device is in an asserted state), the process proceeds to step 182 and the contents of the received information are determined in steps 182 to 202. Processing according to the determination result is performed. That is, in step 182, it is determined whether or not the detection of the optimum light emission intensity for the own apparatus is being executed by the master by determining whether or not the received information is information for intensity detection. If the determination in step 182 is affirmative, the process proceeds to step 190, and light reception state information representing the light reception state of the optical signal by each PD of the PD array 20 is generated based on the light reception amount information input from the signal processing unit 64. Then, the generated light reception state information is output to the LD drive unit 62 via the 8B / 10B encoder 56, the ECC generation unit 58, and the P / S conversion unit 60, and the optical signal reception process is terminated. As a result, each LD of the slave LD array 18 is turned on / off according to the reception state information, so that an optical signal modulated according to the reception state information is emitted from the slave LD array 18 to be detected. After being transmitted through one of the two optical fibers 36, 38, and 40, the second optical sheet bus 42 </ b> B, and the first optical fiber 28, the light is received by the master PD array 20.

  When the master receives the light reception state information from the detection target slave, the master first transmits the intensity detection information based on the light reception state of the optical signal of each PD of the detection target slave PD array 20 indicated by the received light reception state information. It is determined whether the light emission intensity of each LD of the LD array 18 at this time is the optimum light emission intensity of each LD of the LD array 18 when transmitting information to the slave to be detected. As this optimum light emission intensity, for example, a light emission intensity that is in an optimum state in which the light reception amount of each PD of the slave PD array 20 to be detected matches the lower limit of the allowable range of the light reception amount can be applied. When the optimum light emission intensity is set as described above, the life of the master LD array 18 can be maximized, and the amount of heat generated can be suppressed to the minimum necessary. When the received light amount indicated by the received light reception state information is different from the light reception amount corresponding to the optimum state, the light emission intensity is determined according to the received light reception state of each PD of the slave PD array 20 to be detected. After the change is set, the above-described intensity detection information is transmitted again.

  When the above processing is repeated and the received light amount of each PD of the PD array 20 of the detection target slave matches the received light amount corresponding to the optimum state, the master sets the current emission intensity to the master of the detection target slave. The optimum emission intensity of the LD array 18 is stored in the NVM memory 54 in association with the ID of the slave to be detected, and the assert / negate control information is transmitted, so that the identification of the slave to be detected that has been asserted is specified. The chip is negated. By performing the processing as described above for each slave, the optimum emission intensity of the master LD array 18 is detected for all slaves, and the detected optimum emission intensity is stored in the NVM memory 54, respectively. It will be.

  As described above, when the detection of the optimum light emission intensity of the master LD array 18 is completed, in the next step 104 to step 110, the process of detecting the optimum light emission intensity of the slave LD array 18 is sequentially executed by each slave. That is, in step 104, the slave (intensity detection slave) that detects the optimum light emission intensity is determined, and after asserting a specific chip of the intensity detection slave by transmitting the assert / negate control information, the intensity detection slave is set. Intensity detection instruction information for instructing detection of the optimum light emission intensity is transmitted.

  As a result, in the intensity detection slave, the determination in step 180 of the above-described optical signal reception process (see FIG. 9) is affirmed, the determination in step 182 is denied, and the process proceeds to step 184. By determining whether or not the information is instruction information, it is determined whether or not the master has instructed the detection of the optimum light emission intensity. If the determination in step 184 is affirmed, the process proceeds to step 192 to perform optimum light emission intensity detection processing. In this optimum light emission intensity detection process, as in the optimum light emission intensity detection process (step 102 in FIG. 6) previously executed by the master, first, each LD of the LD array 18 is caused to emit light with a predetermined light emission intensity. Send information to the master.

  When the intensity detection information transmitted from the intensity detection slave is received by the master, in the initialization process (FIG. 6), in step 106, in step 190 of the optical signal reception process (FIG. 9) executed by each slave. Similarly to the above, based on the received light amount information input from the signal processing unit 64, light reception state information indicating the light reception state of the optical signal by each PD of the PD array 20 is generated, and the generated light reception state information is converted into the 8B / 10B encoder. 56, the light reception state information is transmitted to the intensity detection slave by outputting to the LD drive unit 62 via the ECC generation unit 58 and the P / S conversion unit 60.

  When the intensity detection slave receives the light reception state information from the master, based on the light reception state of the optical signal by each PD of the master PD array 20 indicated by the received light reception state information, the LD array when the intensity detection information is transmitted first. It is determined whether the light emission intensity of each of the 18 LDs is the optimal light emission intensity of each LD of the LD array 18 when transmitting information to the master. If the received light amount indicated by the received light reception state information is different from the light reception amount corresponding to the optimum state, the light emission intensity is changed and set according to the received light reception state of each PD of the master PD array 20. The above-described intensity detection information is transmitted again. When the light receiving amount of each PD of the master PD array 20 matches the light receiving amount corresponding to the optimum state by repeating the above processing, the intensity detection slave sets the current light emission intensity to the optimum of the LD array 18 of its own device with respect to the master. The light intensity is stored in the NVM memory 54.

  Note that step 192 described above corresponds to the optimization means according to the present invention, and by executing this processing, the slave transmission control unit 52 functions as the optimization means according to the present invention. When the optimum emission intensity detection process in step 192 is completed, in the next step 194, information notifying the detected optimum emission intensity is transmitted to the master, and the optical signal reception process is terminated.

  Upon receiving the optimum emission intensity notification information transmitted from the intensity detection slave, the master associates the optimum emission intensity notified from the intensity detection slave with the ID of the intensity detection slave in step 108 of the initialization process (FIG. 6). And stored in the NVM memory 54. In the next step 110, it is determined whether or not the detection of the optimum light emission intensity has been performed in all the slaves. If the determination is negative, the process returns to step 104 and steps 104 to 110 are repeated. As a result, the optimum emission intensity is detected in all the slaves, and the optimum emission intensity notified from each slave is stored in the NVM memory 54 of the master.

  When detection of the optimum light emission intensity for the optical communication partner is completed in the master and each slave as described above, normal optical communication is performed after the end of the initialization process (FIG. 6). When the master transmits information to an arbitrary slave, the master transmission control unit 52 reads the optimum emission intensity stored in the NVM memory 54 in association with the ID of the information transmission target slave, and reads the optimum Light emission intensity control information for causing each LD of the LD array 18 to emit light with the light emission intensity is output to the LD driving unit 62. Thus, when transmitting information from the master to an arbitrary slave, the light emission intensity of each LD of the master LD array 18 is set so that the received light amount of the optical signal in the PD array 20 of the slave of the information transmission destination is in an optimum state. Be controlled.

  Further, when each slave transmits information to the master, the transmission control unit 52 of each slave reads the optimum emission intensity (the optimum emission intensity of the LD array 18 of each slave with respect to the master) stored in the NVM memory 54, Light emission intensity control information for causing each LD of the LD array 18 to emit light with the read optimum light emission intensity is output to the LD driving unit 62. Thereby, even when information is transmitted from each slave to the master, the light emission intensity of each LD of the LD array 18 of each slave is controlled so that the light reception amount of the optical signal in the master PD array 20 is in an optimum state. . By controlling the light emission intensity of the LD array 18 of the master and each slave as described above, information can be transmitted and received reliably at a low bit error rate by optical communication, and the LD array 18 can emit light with an intensity higher than necessary. By emitting light, it is possible to prevent the life of the LD array 18 from being adversely affected, and it is possible to prevent the LD array 18 from generating more heat than necessary.

  In the next step 112, the optimum light emission intensity notified from each slave and stored in the NVM memory 54 is read, and the read optimum light emission intensity is sorted in ascending or descending order. In step 114, the minimum value of the optimum light emission intensity is searched from the array of the optimum light emission intensity after sorting, and it is determined whether there is one slave having the minimum optimum light emission intensity based on the search result of the minimum value. Note that the slave with the minimum optimum light emission intensity here is not necessarily limited to the slave with the smallest optimum light emission intensity, and the difference from the minimum value of the optimum light emission intensity is within a predetermined value (predetermined value). May be a fixed value or may be a predetermined percentage of the deviation between the maximum value and the minimum value of the optimum light emission intensity). Good.

  For example, as shown in FIG. 10A, the optical communication system 14 is provided with three slaves with IDs 01, 10, and 11, and optical transmission between each slave and the second optical sheet bus 42B. When the distances La, Lb, and Lc of the paths (second optical fibers) are different from each other (La <Lb <Lc), the light amount attenuation amount in the optical transmission path is generally the shortest distance of the optical transmission path (= La) is the smallest in the slave (ID: 01 slave), so that the optimum emission intensity P01, P02, P03 in each slave is also the optimum emission intensity P01 in the ID: 01 slave with the shortest optical transmission distance. Obviously minimal. In such a case, the determination at step 114 is affirmed and the routine proceeds to step 116.

  In the present embodiment, a process of transmitting a dummy optical signal for maintaining high responsiveness of the master PD array 20 during non-communication (specifically, when information is not transmitted from the slave to the master) (present invention) The slave that executes the processing corresponding to the predetermined processing is called a main slave. In step 116, the slave having the smallest optimal light emission intensity is set as the main slave, and the ID of the slave is set as the main slave ID. Remember me. In step 118, assert / negate control information is transmitted to assert a specific chip of the slave set as the main slave, and then a predetermined command is transmitted to the slave set as the main slave. Notify that the main slave has been set. After that, the assert / negate control information is transmitted to the slave set as the main slave, so that the specific chip of the slave set as the main slave is negated, and then the process proceeds to step 128.

  On the other hand, for example, as shown in FIG. 11A, an optical transmission path between three slaves (ID: 01, 10, 11) provided in the optical communication system 14 and the second optical sheet bus 42B. When the distances La, Lb, and Lc of the (second optical fiber) are equal (La = Lb <Lc), the light amount attenuation amount in the optical transmission path is the shortest (= La, Lb). ) Of two slaves (ID: 01, 10 slaves) are almost equal and minimum, so that the optimum light emission intensity P01, P02, P03 in each slave is also the ID of the shortest optical transmission line ID: 01,10 The optimum emission intensities P01 and P02 in the two slaves are minimized. As described above, when there are M slaves (M ≧ 2) having the minimum optimal light emission intensity, the determination in step 114 is denied and the process proceeds to step 120, and M slaves having the minimum optimal light emission intensity are transferred. The Nth (1 ≦ N ≦ M) slave among the slaves is set as the main slave.

  In step 122, the IDs of M slaves (slave candidates for main slaves) having the minimum optimal light emission intensity are stored in the NVM memory 54, and the ID of the slave set as the main slave is stored in the slave of the slave set as the main slave. The history information representing the history is stored in the NVM memory 54. In step 124, a command notifying that the main slave has been set is transmitted to the slave set as the main slave. After starting a timer with a fixed timer time in the next step 126, the process proceeds to step 128. In step 128, the communication prohibition flag is initialized to 0, and the initialization process is terminated.

Steps 112 to step 126 described above corresponds to the setting hand stage according to claim 1, 2, steps 116 and 118 in the setting means according to claim 1, step 120-126 the claims 2 It corresponds to the setting means described in. Then, by executing these steps, the master transmission control unit 52 functions as the setting means described in claims 1 and 2 .

  When the command transmitted in the above step 118 or 124 is received by the slave set as the main slave, the above-described optical signal reception processing (see FIG. 9) is started in this slave, and the determination in step 180 is affirmed. If the determinations in steps 182 and 184 are respectively denied, the process proceeds to step 186, and whether or not the received information is a command for notifying the main slave is determined, so that the device is set as the main slave. It is determined whether or not. If the determination in step 186 is affirmed, the process proceeds to step 196, and information indicating that the own apparatus is a main slave is stored in the NVM memory 54. In step 198, the transmission of the dummy optical signal is started, and the optical signal reception process is terminated.

  For transmission of the dummy optical signal, for example, dummy data in which all bits are 0 or all bits are 1 is transmitted to the LD drive unit 62 via the 8B / 10B encoder 56, the ECC generation unit 58, and the P / S conversion unit 60. (The above dummy data is converted into DC balanced data by the 8B / 10B encoder 56). As a result, a dummy optical signal is transmitted from the LD array 18 to the master PD array 20, and the master PD array 20 is maintained in a highly responsive state while receiving the dummy optical signal.

  In this embodiment, the communication between the master and each slave is performed by the master specifying a write address and write data and instructing data write ("write") to a specific chip of a specific slave. This is done by designating a read address and instructing the specific chip of the specific slave to read data ("read"), and transmitting the data read by the specific chip of the specific slave to the master. In the present embodiment, an interruption occurs when it is necessary to read or write data, and the data communication interrupt process shown in FIG.

  In this data communication interrupt process, first, in step 140, it is determined whether or not the communication prohibition flag is “0”. This communication prohibition flag is set to “1” during the execution of a timer interrupt process, which will be described later. If the determination is negative, the determination in step 140 is repeated, so that the timer interrupt process is executed. Wait until it is finished. If the determination in step 140 is affirmative, the process proceeds to step 142, and the assert / negate control information is transmitted to assert the specific chip (transmission destination chip) of the specific slave (transmission destination slave) that writes or reads data. To. In the next step 144, it is determined whether the process for the destination chip is “data read” or “data write”, and the process branches according to the determination result. When the processing for the destination chip is “read data”, the process proceeds from step 144 to step 148, and the read control information including the read address is transmitted to the destination slave. In the next step 148, it is determined whether or not read data is received from the transmission destination slave, and the process waits until the determination is affirmed.

  When this read control information is received by the transmission destination slave, the above-mentioned optical signal reception process (see FIG. 9) is started by this transmission destination slave, the determination of step 180 is affirmed, and steps 182 to 186 are performed. When each determination is denied, the process proceeds to step 188, where it is determined whether or not the received information is a command for notifying the main slave setting release, whether or not the main slave setting for the own device is released. Determined. If the determination in step 186 is negative, the process proceeds to step 202, processing according to the received information is performed, and the optical signal reception process is terminated.

  For example, when the received information is read control information, in step 202 described above, the received read control information is converted into a specific image of the electronic circuit 12 corresponding to the destination chip via the asserted destination chip. Processing to deliver to the processing circuit is performed. As a result, the specific image processing circuit reads data from the read address specified by the read control information in the built-in memory, and outputs the read data to the destination chip. When read data is input from a specific image processing circuit, the destination slave performs a process of transmitting the input read data to the master (this process is also a part of step 202). When the transmission destination slave is set as the main slave, the transmission of the dummy optical signal to the master PD array 20 is interrupted when the read data is transmitted. During this time, the master PD array 20 Since the optical signal corresponding to the read data is received, the responsiveness is maintained high.

  When the read data is received by the master, the determination in step 150 of the data communication interrupt process (FIG. 7) is affirmed, the process proceeds to step 152, and the assertion / negate control information is transmitted to thereby determine the destination slave. A specific chip is negated, and the data communication interrupt process is terminated.

  On the other hand, when the process for the destination chip is “data writing”, the process proceeds from step 144 to step 146, and after writing control information including a write address and write data is transmitted to the destination slave, step 152 is performed. By transmitting assert / negate control information in step, the specific chip of the destination slave is negated, and the data communication interrupt process is terminated.

  Even when the write control information is received by the transmission destination slave, the optical signal reception process (FIG. 9) is started by the transmission destination slave, the determination of step 180 is affirmed, and the determinations of steps 182 to 188 are respectively performed. If the result is negative, the process proceeds to step 202. If the received information is write control information, in step 202, the received write control information is sent to the specific image processing circuit of the electronic circuit 12 corresponding to the destination chip through the asserted destination chip. Processing to deliver to is performed. Thereby, in a specific image processing circuit, a process of writing the write data included in the write control information to the write address specified by the write control information in the built-in memory is performed.

  While the above “data read” and “data write” are performed, assert / negate control information, read control information, and write control information are received by each slave other than the transmission destination slave, and an optical signal is received. Although processing at the time of reception (FIG. 9) is performed, the determination at steps 180 and 204 is denied for slaves other than the main slave, so that the processing at the time of optical signal reception is terminated without performing any processing. On the other hand, in the main slave, the determination in step 204 is affirmed, and the process proceeds to step 206. Based on the received information, one of the chips provided in each slave is asserted and data is read out. It is determined whether or not.

  When data is read, as described above, read data is transmitted from the slave instructed to read data to the master, and the master PD array 20 receives the light corresponding to the read data. Since the responsiveness is maintained by receiving the signal, the main slave does not need to transmit the dummy optical signal, and the transmission of the dummy optical signal may adversely affect the transmission and reception of the read data There is also. For this reason, when the determination in step 206 is affirmed, the process proceeds to step 208, the transmission of the dummy optical signal is stopped, and the optical signal reception process is terminated.

  If the determination in step 206 is negative, the process proceeds to step 210, and has the status changed from a situation where there are asserted chips to a situation where all the chips including the chip are negated? Judge whether or not. If the determination is negative, the optical signal reception process is terminated without performing any processing. If the determination in step 210 is affirmative, the process proceeds to step 212 and the transmission of the dummy optical signal is started. The process at the time of reception ends. Therefore, only when “data read” is performed by the above processing, transmission of the dummy optical signal from the main slave to the master is temporarily stopped, and the dummy optical signal when the chip involved in the data read is negated. Therefore, the master PD array 20 is always maintained in a highly responsive state.

  In the above-described initialization process (FIG. 6), there is only one slave having the smallest optimum light emission intensity (determination in step 114 is affirmative), and when the slave is set as the main slave, When the dummy optical signal is transmitted by the slave, the total light emission time t1 of the LD array 18 in the slave set as the main slave is “data read” as shown in FIG. 10B as an example. Accordingly, the light emission time t2 for transmitting the read data to the master is added to the light emission time tx for transmitting the dummy optical signal, so that it does not function as a main slave (the optimum light emission intensity is larger). The total emission time of the LD array 18 is longer than that of the slave, and the product of the emission intensity (= optimum emission intensity) of the LD array 18 of each slave and the total emission time. The difference of this value (corresponding to the area of the region indicated by hatching in FIG. 10 (B)) is reduced (averaged).

  Since the lifetime of the LD array 18 is roughly determined according to the product of the emission intensity of the LD array 18 and the total emission time, the lifetime of the LD array 18 of each slave can be averaged by the above, and the LD of a specific slave can be averaged. Since the life of the array 18 can be prevented from becoming extremely short, the life of the slave PD array 20 can be extended without deteriorating the responsiveness of the master PD array 20.

  In the above initialization process (FIG. 6), if there are M slaves (M ≧ 2) having the minimum optimum light emission intensity, a timer with a fixed timer time is started in step 126. When this timer times out, an interrupt is generated, and the timer interrupt process shown in FIG.

  In this timer interrupt process, first, in step 160, it is determined whether the data communication interrupt process (FIG. 7) described above is being executed, and step 160 is repeated until the determination is affirmed. If the determination at step 160 is affirmative, the routine proceeds to step 162, where the communication prohibition flag is set to “1”. As a result, even if the data communication interrupt process is started during the execution of this timer interrupt process, the execution of the data communication interrupt process is stopped until the timer interrupt process is completed. become. In the next step 164, based on the history information stored in the NVM memory 54 (information indicating the history of the slave set as the main slave) and (ID of M slaves as main slave candidates), the main slave is newly set. Determine the slave to be set. This determination can be performed, for example, so that the slave set as the main slave rotates (circulates) in order among the M slaves as main slave candidates.

  In the next step 166, a command for notifying the main slave setting release is transmitted to the slave currently set as the main slave. When this command is received by the slave set as the main slave, the optical signal reception processing (see FIG. 9) is started by the slave, the determination of step 180 is affirmed, and the determinations of steps 182 to 186 are respectively performed. When the determination is negative and the determination at step 188 is affirmed, the process proceeds to step 200. In step 200, the NVM memory 54 stores that the setting of the main slave for the device itself has been cancelled, and if transmission of the dummy optical signal is being performed, the transmission of the dummy optical signal is stopped and then the optical signal is received. End time processing.

  In the timer interrupt process, in the next step 168, the ID of the slave newly set as the main slave is stored in the NVM memory 54 as history information. In step 168, a command notifying the setting of the main slave is transmitted to the slave newly set as the main slave. When this command is received by the slave newly set as the main slave, the optical signal reception processing (see FIG. 9) is started by the slave, the determination of step 180 is affirmed, and the determination of steps 182 to 184 is performed respectively. When the determination is negative and the determination in step 186 is affirmed, the process proceeds to step 196. Thereby, in the slave newly set as the main slave, information indicating that the own apparatus is the main slave is stored in the NVM memory 54 (step 196), and transmission of the dummy optical signal is started (step 198). Later, the optical signal reception process is terminated.

In the timer interrupt process, the timer having a fixed timer time is restarted in the next step 172, the communication prohibition flag is set to 0 in step 174, and the process ends. When the timer started in step 172 times out, the above timer interrupt process is started again, and the slave functioning as the main slave is switched again. Steps 164 to 172 described above correspond to the invention described in claim 2, and steps 162 and 174 correspond to the prohibition control means described in claim 4 .

  As described above, when there are M (plural) slaves having the minimum optimum light emission intensity, and the slave that functions as the main slave is rotated among the M slaves, the slave that functions as the main slave. By switching the (slave transmitting the dummy optical signal) in order, as shown in FIG. 11B as an example, the total light emission time t1 of the LD array 18 in the M slaves functioning as the main slave is “data Since it is a time obtained by adding a light emission time tx / M for transmitting a dummy optical signal (M = 2 in the example of FIG. 11) to a light emission time t2 for transmitting read data to the master in accordance with “Reading”. The total light emission time of the LD array 18 is longer than other slaves that do not function as the main slave (slave with ID: 11), and the LD array of each slave is The difference in emission intensity (= the optimal light emission intensity) and the value corresponding to the product of the total light emitting time (corresponding to the area of the region indicated by hatching in FIG. 11 (B)) of b 18 is reduced (averaged).

  Therefore, in this case as well, the life of the LD array 18 of each slave can be averaged, and the life of the LD array 18 of a specific slave can be prevented from becoming extremely short. The life of the PD array 20 of each slave can be extended without causing the deterioration of the responsiveness.

  In the above, the initialization process is performed when the power is turned on and the elapsed time from the previous execution of the initialization process reaches a predetermined time, and the main slave is based on the optimum light emission intensity each time the initialization process is performed. However, the present invention is not limited to this, and there are M (plural) slaves having the minimum optimum light emission intensity. Once it is decided to rotate, the number of times of power-on or initialization process is counted every time the power is turned on or the initialization process is executed. The slave that functions as the main slave may be switched each time the value reaches In the above aspect, the time for which each of the M slaves functions as the main slave is not necessarily constant, but the product of the light emission intensity and the total light emission time of the LD array 18 of each slave is also averaged by the above processing. be able to.

In the above, when there are M (plural) slaves having the minimum optimum light emission intensity, the main timer is started by starting a timer with a fixed timer time each time a slave functioning as a main slave is set or switched. Although an example has been described in which a fixed time is assigned to each of the M slaves as candidate slaves to function as the main slave, the present invention is not limited to this, and the M slaves as main slave candidates are not limited thereto. When the optimum light emission intensity is slightly different, the time for functioning as the main slave may be made different for each slave according to the difference in the optimum light emission intensity in each of the M slaves. The above matter corresponds to the invention described in claim 3 . Further, the total light emission time of the LD array 18 in each slave is measured, and the time for functioning as the main slave is increased so that the time for functioning as the main slave becomes longer as the measured value of the total light emission time becomes shorter. It may be set every time. In addition to the measurement value of the total light emission time, the optimum light emission intensity is also considered, and the time for functioning as the main slave is set for each slave so that the product of the optimum light emission intensity and the measurement value of the total light emission time is equal. It is also possible.

  In the above description, an example in which a function corresponding to the setting unit of the present invention is provided in the master has been described. However, the present invention is not limited to this, and the slaves can communicate with each other as in the optical communication system 14 according to the present embodiment. Even if the configuration is such that the slave cannot send / receive directly, it is possible for the slaves to send and receive information indirectly via the master. Therefore, using this, a function corresponding to the setting means of the present invention is provided on the slave side. It is also possible.

  Furthermore, although a full-color printer has been described as an example of the electronic device 10 in the above, it is needless to say that the present invention is not limited to this and can be applied to any electronic device such as a computer.

It is a block diagram which shows schematic structure of the optical communication system which concerns on this embodiment. It is a perspective view which shows the external appearance of an optical sheet bus | bath. (A) is a waveguide member embedded in the base member of the optical sheet bus, and (B) is a perspective view showing the internal structure of the optical sheet bus together with the input and output of optical signals in the first optical sheet bus. (A) is a waveguide member, (B) is a perspective view which shows the internal structure of an optical sheet bus | bath with the incident / exit of the optical signal in a 2nd optical sheet bus | bath, respectively. It is a block diagram which shows schematic structure of an optical communication control part. It is a flowchart which shows the content of the initialization process performed with a master. It is a flowchart which shows the content of the data communication interruption process performed with a master. It is a flowchart which shows the content of the timer interruption process performed with a master. It is a flowchart which shows the content of the process at the time of the optical signal reception performed with a slave. (A) is a conceptual diagram schematically showing an optical communication system with one slave having the minimum optimum light emission intensity, and (B) shows the relationship between the light emission time and light emission intensity of the LD array of each slave in the system of (A). FIG. (A) is a conceptual diagram schematically showing an optical communication system in which a plurality of slaves having the optimum light emission intensity is present, and (B) is a relationship between light emission time and light emission intensity of the LD array of each slave in the system of (A). FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Electronic device 12 Electronic circuit 14 Optical communication system 16 Optical communication I / F part 18 LD array 20 PD array 22 Optical communication control part 42A First optical sheet bus 42B Second optical sheet bus 52 Transmission control part 54 NVM memory

Claims (6)

A first device including a first light emitting element and a first light receiving element; a plurality of second devices each including a second light emitting element and a second light receiving element; and the first device modulated according to arbitrary information. A first optical signal transmission body that transmits optical signals emitted from the first light emitting elements to the plurality of second devices and receives light by the second light receiving elements of the plurality of second devices, respectively; modulated according to the information each is transmitted to the first device an optical signal emitted from the second light emitting element of the plurality of second devices, first it is received by the first light receiving element of the first device An optical communication system comprising two optical signal transmitters,
Light receiving state information that is provided in each of the plurality of second devices , causes the second light emitting element of the corresponding second device to emit light, and indicates a light receiving state by the first light receiving element of the first device. If the received light reception state information is different from the optimum value for receiving an optical signal, the second light emitting element emits light by changing the light emission intensity of the second light emitting element. by repeating thereby, the emission intensity of the second light emitting element of the corresponding second device and the optimization means for optimizing,
Optimized by the optimization means provided in the first device or provided in one second device having a function of transmitting / receiving information to / from another second device via the first device. Based on the light emission intensity of the second light emitting element of each of the plurality of second devices after the conversion has been performed in all the second devices, the single light emitting element having the smallest light emission intensity of the second light emitting element. Setting means for setting two devices as a specific second device;
With
When information is not transmitted from each of the plurality of second devices to the first device, the second light emitting element is caused to emit light and a predetermined optical signal is transmitted to the first light receiving element of the first device. An optical communication system , wherein a predetermined process for receiving light is executed by the specific second device . A first device including a first light emitting element and a first light receiving element; a plurality of second devices each including a second light emitting element and a second light receiving element; and the first device modulated according to arbitrary information. A first optical signal transmission body that transmits optical signals emitted from the first light emitting elements to the plurality of second devices and receives light by the second light receiving elements of the plurality of second devices, respectively; modulated according to the information each is transmitted to the first device an optical signal emitted from the second light emitting element of the plurality of second devices, first it is received by the first light receiving element of the first device An optical communication system comprising two optical signal transmitters,
Light receiving state information that is provided in each of the plurality of second devices , causes the second light emitting element of the corresponding second device to emit light, and indicates a light receiving state by the first light receiving element of the first device. If the received light reception state information is different from the optimum value for receiving an optical signal, the second light emitting element emits light by changing the light emission intensity of the second light emitting element. by repeating thereby, the emission intensity of the second light emitting element of the corresponding second device and the optimization means for optimizing,
Optimized by the optimization means provided in the first device or provided in one second device having a function of transmitting / receiving information to / from another second device via the first device. The plurality of the light emitting elements selected in ascending order of the light emitting intensity of the second light emitting elements based on the light emitting intensity of the second light emitting elements of each of the plurality of second apparatuses after the conversion is performed in all the second apparatuses. Setting means for setting the second device as a specific second device;
With
When information is not transmitted from each of the plurality of second devices to the first device, the second light emitting element is caused to emit light and a predetermined optical signal is transmitted to the first light receiving element of the first device. Of the plurality of specific second devices is executed by one second device of the plurality of specific second devices, and the second device that executes the predetermined processing is included in the plurality of specific second devices. An optical communication system characterized by switching the second device for executing the predetermined processing every time a predetermined time elapses so as to circulate . According to the difference in the light emission intensity of the second light emitting element in each of the plurality of specific second devices so that the product of the light emission intensity and the light emission time of the second light emitting element of each second device is uniform. The predetermined time is set for each of the plurality of specific second devices , and the predetermined processing is executed each time a predetermined time corresponding to the second device executing the predetermined processing elapses. optical communication system of claim 2, wherein the switching the second device. Between being executed is open beginning of the process of switching the second device to execute the predetermined processing until the processing is completed, the prohibition control means for prohibiting the communication to the first device from the second device The optical communication system according to claim 3, further comprising: A first device including a first light emitting element and a first light receiving element; a plurality of second devices each including a second light emitting element and a second light receiving element; and the first device modulated according to arbitrary information. A first optical signal transmission body that transmits optical signals emitted from the first light emitting elements to the plurality of second devices and receives light by the second light receiving elements of the plurality of second devices, respectively; modulated according to the information each is transmitted to the first device an optical signal emitted from the second light emitting element of the plurality of second devices, first it is received by the first light receiving element of the first device In an optical communication system comprising two optical signal transmitters,
When the second light emitting element of one second device emits light and the amount of light received by the first light receiving element of the first device is different from the optimum value for receiving an optical signal, The second light emitting element of the one second device is repeatedly emitted by changing the light emission intensity of the second light emitting element of the two second devices and causing the second light emitting element of the one second device to emit light. the emission intensity to optimize conducted each for the plurality of second devices,
Based on the emission intensity of the second light emitting element of each of the plurality of second devices after performing the optimization for all of the second device, a single light emitting intensity minimum of the second light emitting element Set the second device as a specific second device,
When information is not transmitted from each of the plurality of second devices to the first device, the second light emitting element is caused to emit light and a predetermined optical signal is transmitted to the first light receiving element of the first device. An optical communication control method characterized in that a predetermined process for receiving light is executed by the specific second device . A first device including a first light emitting element and a first light receiving element; a plurality of second devices each including a second light emitting element and a second light receiving element; and the first device modulated according to arbitrary information. A first optical signal transmission body that transmits optical signals emitted from the first light emitting elements to the plurality of second devices and receives light by the second light receiving elements of the plurality of second devices, respectively; modulated according to the information each is transmitted to the first device an optical signal emitted from the second light emitting element of the plurality of second devices, first it is received by the first light receiving element of the first device In an optical communication system comprising two optical signal transmitters,
When the second light emitting element of one second device emits light and the amount of light received by the first light receiving element of the first device is different from the optimum value for receiving an optical signal, The second light emitting element of the one second device is repeatedly emitted by changing the light emission intensity of the second light emitting element of the two second devices and causing the second light emitting element of the one second device to emit light. the emission intensity to optimize conducted each for the plurality of second devices,
A plurality of light emitting elements selected in ascending order of the light emitting intensity of the second light emitting elements based on the light emitting intensity of the second light emitting elements of each of the plurality of second apparatuses after performing the optimization in all the second apparatuses . Setting the second device as a specific second device;
When information is not transmitted from each of the plurality of second devices to the first device, the second light emitting element is caused to emit light and a predetermined optical signal is transmitted to the first light receiving element of the first device. Of the plurality of specific second devices is executed by one second device of the plurality of specific second devices, and the second device that executes the predetermined processing is included in the plurality of specific second devices. An optical communication control method characterized by switching the second device for executing the predetermined processing every time a predetermined time elapses .

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