JP2007053675A - Optical signal transmission apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical signal transmission apparatus, capable of checking an operation state of a receiving side or a reception fault in optical transmission by a transmitter side, using a simple configuration. <P>SOLUTION: Signaling between a host 110 and a monitor 120 via an optical fiber 30 is performed for a TMDS (Transmission Minimized Differential Signaling) Data, and signaling via a metal cable 40 is performed with respect to a display control signal. On the transmitter side, a transmitting module 10 is connected with an operation display unit 10a. On the receiver side, a receiving module 20 is connected. If a fault is detected on the receiving module 20 side, since HPD (Hot Plug Detect) signal is changed, the transmitting module 10 causes an LED for RxON to be turned on at the operation display unit 10a, based on the HPD signal. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an optical signal transmission device, and more particularly to an optical signal transmission device for transmitting a high-speed video signal over a long distance.

  In recent years, a system using a combination of a computer and a display, a combination of a video reproduction device and a projector, etc. has been handling high definition video and images, and a digital signal is used for the signal processing. For example, a DVI (Digital Visual Interface) signal formulated by an industry group, DDWG (Digital Display Working Group), uses a differential signal standard called TMDS (Transmission Minimized Differential Signaling), and a maximum of 1.65 Gbps per bit. High-speed transmission is possible.

  FIG. 14 shows a conventional video system using a metal cable. The video system 100 includes a host 110, a monitor 120 that displays an image based on a video signal from the host 110, and a metal DVI cable 130 that connects the monitor 120 to the host 110.

  FIG. 15 shows a configuration of a transmission signal in the DVI metal cable 130 in FIG. The metal DVI cable 130 connects the DVI connector 11 provided in the host 110 and the DVI connector 21 provided in the monitor 120, and a data line 130a for transmitting TMDS data by an electric differential pair; A control line 130b for transmitting a display control signal and a GND line 130c are provided.

  The data line 130a transmits the RGB signals (TMDS Data0 ± to TMDS Data2 ±) and the dot clock signal (TMDS Clock ±) of the pixels. The RGB signal is serialized at a speed 10 times the pixel clock by an encoding process in accordance with the DVI standard, and converted into a 3-bit TMDS signal. Further, the dot clock is also converted into a TMDS signal.

The control line 130b transmits display control signals such as “5V power”, “DDC (Display Data Channel) Clock”, “DDC Data”, and HPD (Hot Plug Detect). “DDC Clock” and “DDC Data” are signals for obtaining individual information such as resolution that the host 110 can display on the monitor 120. The protocol is specifically defined by VESA (Video Electronics Standard Association), and the electrical specification is in accordance with the I ² C specification. 5V power and HPD are connection confirmation signals for the host 110 and the monitor 120.

  The host 110 transitions “5V power” from Low to High after being activated when the power is turned on. When the monitor 120 recognizes the state, the monitor 120 changes the HPD from Low to High. Next, the host 110 recognizes that the monitor 120 is normally connected based on the transition state of the HPD.

  Applications of the video system described above include video distribution in stations, schools, hospitals, and large screen displays in living rooms and concert halls. In such applications, it has become necessary to increase the distance between the video transmission device (host) and the video display device (monitor). However, when a conventional metal cable is used to transmit a digital signal having a data rate exceeding gigahertz, signal degradation is severe, and it is difficult to transmit a DVI signal over a long distance exceeding 10 m, for example. In view of this, video distribution systems that transmit high-definition images over long distances using an optical link made of a semiconductor laser and an optical fiber instead of a metal cable are being studied.

  By the way, the optical link has some problems for convenience. For example, a driving circuit for converting an electrical signal into light on the transmitting side and an optical signal into electricity on the receiving side is necessary, and power supply for that is required. Also, semiconductor lasers and optical fibers that generate optical signals are more prone to failure than metal cables, and signals cannot be transmitted simply by connecting them.

  Therefore, there is a configuration in which an operation state display unit is provided in the transmission device so that the operation state of the system is always visible. For example, an automatic gain control (AGC) circuit detects whether the reception level of the optical fiber is equal to or higher than a certain level ( There is known a diagnostic device that generates a DET) signal, determines whether or not the optical fiber is disconnected based on the DET signal, and displays the result on a display device (see, for example, Patent Document 1). .

In addition, the transmission side and the reception side are connected by an optical fiber, and a photoelectric converter, a display drive circuit, and a display are installed in the optical transmitter on the transmission side and the optical receiver on the reception side. An optical repeater is also known that displays the occurrence of an abnormality on the display of the optical transmitter when detected, and displays the occurrence of the abnormality on the display of the optical receiver when an abnormality is detected on the receiving side. (For example, refer to Patent Document 2).
JP-A-5-22755 ([0010], [0011], FIG. 1). JP 2003-60570 A [0021] to [0030], [0047] to [0053], FIG. 1).

  However, in conventional optical signal transmission devices, the optical receiver is often placed in a place far away from the optical transmitter or operator, or in a place where it is difficult for the human eye to see, such as the ceiling or the back of a wall. Is displayed on the receiving side, so it is difficult for the operator to notice an abnormality or failure.

  In addition, optical transmission requires peripheral circuits in addition to optical fibers, and is likely to be more expensive than metal cables. In the conventional optical signal transmission apparatus, the configuration becomes complicated, and an increase in cost is inevitable.

  Accordingly, an object of the present invention is to provide an optical signal transmission apparatus capable of confirming an operation state on the reception side and reception abnormality of optical transmission on the transmission side with a simple configuration.

  In order to achieve the above object, according to a first aspect of the present invention, an optical transmission unit that converts an image electrical signal transmitted from a host device into an image optical signal, and the optical transmission unit transmitted via an optical transmission medium. An optical receiver that converts the image optical signal into an electrical image signal and outputs an image to an output device; a transmission medium that is different from the optical transmission medium that transmits a control signal between the host device and the output device; Provided is an optical signal transmission device provided with a status display unit provided on the optical transmission side and detecting and displaying the status of the reception side from the control signal.

  According to the optical signal transmission device according to the first aspect, the reception-side operation state or optical transmission is detected by detecting the reception-side state from the control signal from the output device side and displaying it on the optical transmission side. Can be confirmed on the transmission side. The output device includes a printing device, a display device, and the like.

  In order to achieve the above object, according to a second aspect of the present invention, an optical transmission unit that converts an image electrical signal transmitted from a host device into an image optical signal, and an optical transmission medium transmitted from the optical transmission unit. An optical receiver that converts the image optical signal into an electrical image signal and outputs an image to an output device; and a transmission medium that is provided on the optical reception side and that indicates a state on the reception side is different from the optical transmission medium. A status signal transmission unit that transmits to the optical transmission unit via a status display unit that is provided on the optical transmission side and displays the status of the reception side based on the status signal transmitted from the status signal transmission unit; An optical signal transmission device characterized by comprising:

  According to the optical signal transmission device according to the second aspect, the reception side state is displayed by the state display unit provided on the optical transmission side based on the state signal from the state signal transmission unit. The transmission side can confirm the operation state of the side and the reception abnormality of the optical transmission. The output device includes a printing device, a display device, and the like.

  The optical transmission medium is an optical fiber, and the transmission medium different from the optical transmission medium is preferably a metal cable. Since an optical fiber does not have signal degradation like a metal cable, a high-speed image light signal can be transmitted even if the distance between the optical transmitter and the optical receiver is large.

  The status display unit can display the status on the receiving side based on a status signal output from the output device. An HPD (Hot Plug Detect) signal can be used as the status signal.

  The status display unit can display the status on the receiving side based on an optical reception status signal in the optical reception unit. An LOP (Loss Of Power) signal can be used as the optical reception state signal.

  The status display unit includes a first display element driven by a power supply voltage being supplied to the optical transmission unit, and a second display element driven by an HPD (Hot Plug Detect) signal included in the status signal. It can be set as the structure provided with.

  The status display unit includes a first display element driven by a power supply voltage being supplied to the optical transmission unit, and a second display element driven by an HPD (Hot Plug Detect) signal included in the status signal. And a third display element for abnormal display driven by a LOP (Loss Of Power) signal from the optical receiver.

  The optical receiving unit includes a plurality of signal conversion circuits that individually photoelectrically convert each data transmitted from the optical transmission medium, and a plurality of optical signal state detection units that determine a reception state of the individual optical signals. And a logical sum circuit that takes the logical sum of the output signals of the plurality of signal state detectors and sends the result as a LOP (Loss Of Power) signal to the optical transmitter. .

  The plurality of signal conversion circuits include a light receiving element that receives an optical signal and converts the light signal into an electrical signal, and an LOP detection unit that generates the LOP signal based on a comparison result between a light reception level of the light receiving element and a preset threshold value. It can be set as the structure provided with.

  The status display unit is preferably installed in the vicinity of the optical receiving unit or the host device.

  According to the optical signal transmission device of the present invention, it is possible to check the operation state of the reception side and the reception abnormality of the optical transmission on the transmission side with a simple configuration.

[First Embodiment]
FIG. 1 shows an optical signal transmission apparatus according to a first embodiment of the present invention. This optical signal transmission device 1 includes a transmission module (TX) 10 as an optical transmission unit connected to a host 110 via a metal DVI cable 130A, and an optical reception unit connected to a monitor 120 via a metal DVI cable 130B. The module 10 and 20 are connected by an optical fiber 30 for transmitting an image electrical signal (TMDS signal) and a metal cable 40 for transmitting a display control signal. .

  The transmission module 10 is supplied with power from the external power supply 51A, converts a high-speed (maximum 1.65 Gbps) TMDS signal transmitted from the host 110 via the metal DVI cable 130A into an optical signal, and converts the optical signal into an optical signal. It transmits to the receiving module 20 via the fiber 30, and is provided with an operation display unit 10a as a state display unit that displays an operation state by LEDs 15A and 15B.

  The receiving module 20 is supplied with power from the external power supply device 51B, converts an optical signal transmitted from the transmitting module 10 through the optical fiber 30 into an electrical signal, and monitors the electrical signal through the metal DVI cable 130B. To send to.

  Four optical fibers 30 are provided in accordance with the number of TMDS bits. As the material of the fiber, either resin or quartz can be used. Since this optical fiber 30 has much less signal degradation than a metal cable, it can have a length exceeding 10 m.

  The metal cable 40 has the same function as the control line 130b and the GND line 130c of the DVI cable 130 shown in FIG. As this metal cable 40, for example, a commercially available LAN cable can be used. The reason why the metal cable 40 is used for transmitting the display control signal is that the frequency of the display control signal is usually about 100 kHz, so that it is not necessary to use a high-speed optical fiber. It doesn't matter.

  As the external power supply devices 51A and 51B, AC adapters used in many electronic devices and home appliances, or the like can be used.

(Configuration of transmission signal)
FIG. 2 shows a configuration of a transmission signal between the modules 10 and 20. The transmission module 10 includes a DVI connector 11 and E / O (electrical-optical) conversion circuits 12A, 12B, 12C, and 12D that convert TMDS data from the host 110 into an optical signal and output the optical signal to the optical fiber 30. The E / O conversion circuit is a circuit that receives a differential TMDS signal and converts it into a corresponding optical signal. Specifically, the E / O conversion circuit 12A performs electro-optical conversion of Data0, the E / O conversion circuit 12B performs electro-optical conversion of Data1, and the E / O conversion circuit 12C performs electro-optical conversion of Data2. The E / O conversion circuit 12D converts the clock into electro-optical.

  The receiving module 20 receives optical signals from the DVI connector 21 and the optical fiber 30, and converts them into corresponding differential TMDS signals as O / E (optical-electrical) conversion circuits 22A, 22B, and 22C. , 22D. Specifically, the O / E conversion circuit 22A performs photoelectric conversion on Data0, the O / E conversion circuit 22B performs photoelectric conversion on Data1, and the O / E conversion circuit 22C performs photoelectric conversion on Data2. The O / E conversion circuit 22D performs photoelectric conversion of the clock.

  The metal cable 40 includes four lines for transmitting display control signals including “5V power”, “DDC (Display Data Channel) Clock”, “DDC Data”, and “HPD (Hot Plug Detect)”, and a GND line. Have As described above, “DDC Clock” and “DDC Data” are signals for obtaining individual information such as resolution that the host 110 can display on the monitor 120, and “5V power” and “HPD” And a signal for confirming the connection of the monitor 120.

(Configuration of transmission module)
FIG. 3 shows a detailed configuration of the transmission module 10. The transmission module 10 includes the DVI connector 11, the E / O conversion circuits 12A to 12D, the operation display unit 10a, the buffer circuit 13 connected between the DVI connector 11 and the metal cable 40, and the operation display unit. 10a and an internal switch 14 for controlling power supply to the transmission module.

  The operation display unit 10a includes an LED 15A as a first display element for TxON display and an LED 15B as a second display element for RxON display. The LED 15A is connected between the output terminal of the internal switch 14 and GND. The LED 15B is connected between the input side of “HPD” of the DVI connector 11 and GND.

  The buffer circuit 13 is provided to prevent deterioration of the control signal, and is effective when the length of the metal cable 40 is increased. The buffer circuit 13 includes a buffer 13a that performs one-way communication from the host 110 to the monitor 120 for “DDC Clock”, a buffer 13b that performs two-way communication for “DDC Data”, and “HPD”. And a buffer 13c for performing one-way communication from the monitor 120 to the host 110.

  The signal “5V power” of the DVI connector 11 turns on the internal switch 14 and transmits the DC 5V output from the external power supply device 51A to the reception module 20 as “Tx 5V”. The buffer circuit 13 may not be provided when the metal cable 40 is short and the signal deterioration is small.

(Configuration of E / O conversion circuit)
FIG. 4 shows details of the E / O conversion circuits 12 </ b> A to 12 </ b> D of the transmission module 10. Here, since the E / O conversion circuits 12A to 12D have the same configuration, one of them will be described as the E / O conversion circuit 12, and the input data will be described as TMDS Data + and TMDS Data-.

  The E / O conversion circuit 12 includes a laser diode (LD) 41 as a light emitting element, an LD driver 42 that supplies a drive current to the LD 41 based on TMDS Data + and Data− of differential signals, and an LD 41 regardless of the surrounding environment. And a laser power controller 43 that controls the LD driver 42 so that the amount of the light becomes constant.

(Reception module configuration)
FIG. 5 shows a detailed configuration of the receiving module 20. The receiving module 20 is operated by the DVI connector 21, the O / E conversion circuits 22A to 22D, the buffer circuit 23 connected between the metal cable 40 and the DVI connector 21, the external power supply 51B and the Tx 5V signal. And an internal switch 24.

  The buffer circuit 23 constitutes a state signal transmission unit together with the metal cable 40, and performs a one-way communication from the host 110 to the monitor 120 for “Clock” and a two-way communication for “Data”. And a buffer 23c for performing one-way communication from the monitor 120 to the host 110 for “HPD”. The buffer circuit 23 may not be provided when the metal cable 40 is short and the signal deterioration is small.

(Configuration of O / E conversion circuit)
FIG. 6 shows details of the O / E conversion circuits 22 </ b> A to 22 </ b> D of the reception module 20. Here, since the O / E conversion circuits 22A to 22D have the same configuration, one of them will be described as the O / E conversion circuit 22, and the differential output data will be described as TMDS Data + and TMDS Data−.

  The O / E conversion circuit 22 includes a photodiode (PD) 61 as a light receiving element, a preamplifier 62 that converts a minute current from the PD 61 into a voltage, and a post that amplifies the output of the preamplifier 62 to match the TMDS signal level. And an amplifier 63.

(Operation of optical signal transmission device)
Next, the operation of the optical signal transmission device 1 will be described with reference to FIGS. As shown in FIG. 3, when the host 110 is turned on and the 5V power signal from the host 110 becomes High and the internal switch 14 is turned on, the transmission module 10 is supplied with power from the external power supply 51A. Is done. When the host 110 is not turned on, the 5V power signal is low, so the internal switch 14 is off and no power is supplied to the transmission module 10.

  When the internal switch 14 is turned on, as shown in FIG. 3, a voltage is applied to the operation display unit 10a, the TxON LED 15A is lit, and the transmission module 10 is displayed in an operating state.

  On the other hand, 3-bit TMDS Data and TMDS Clock from the host 110 are input to the DVI connector 11 of the transmission module 10 via the metal DVI cable 130A, and further input to the E / O conversion circuits 12A to 12D. As shown in FIG. 4, in the E / O conversion circuits 12 </ b> A to 12 </ b> D, the LD 41 is driven by the LD driver 42 so that TMDS Data is electro-optically converted, and this optical signal is transmitted to the optical fiber 30. Also, four types of display control signals from the host 110 are sent to the metal cable 40 through the buffer circuit 13.

  As shown in FIG. 5, the receiving module 20 receives power from the external power supply 51 </ b> B, and is turned on / off by an internal switch 24 controlled by a 5V power signal from the host 110. When power is applied to the host 110, the 5V power signal becomes High, and the internal switch 24 is turned on by the Tx5V signal based on the 5V power signal to supply power to the receiving module 20. At this time, the 5V power signal sent to the monitor 120 is also High.

  The receiving module 20 receives the display control signal from the metal cable 40 by the buffer 23. At this time, if the monitor 120 is connected to the reception module 20, the HPD signal is made high by the monitor 120, and the reception module 20 transmits the information to the transmission module 10 via the metal cable 40. When the transmission module 10 receives the HPD signal via the metal cable 40, the transmission module 10 transmits the HPD signal to the host 110 via the buffer circuit 13, and turns on the RxON LED 15B of the operation display unit 10a. With this lighting, it is possible to confirm the operating states of the monitor 120 and the receiving module 20.

(Effects of the first embodiment)
According to the first embodiment, the following effects are obtained.
(A) The operation state of the reception module 20 and the monitor 120 installed at a remote place or another room from the host 110 can be confirmed by the operation display unit 10a of the transmission module 10 installed near the host 110. For example, when no image is displayed on the monitor 120, it is possible to check whether power is supplied to the receiving module 20 and the monitor 120 and whether the connection between the receiving module 20 and the monitor 120 is normal or abnormal.
(B) Since the TMDS data is transmitted through the optical fiber 30, RGB signals can be transmitted at high speed.
(C) Since the display control signal is transmitted by the metal cable 40 without using the optical fiber 30, the cost can be reduced.

[Second Embodiment]
FIG. 7 shows an optical signal transmission apparatus according to the second embodiment of the present invention. The present embodiment is obtained by adding a LOP (Loss Of Power) signal indicating the loss of an optical signal to the signal transmitted by the metal cable 40 in the first embodiment. This is the same as in the first embodiment.

  FIG. 8 shows a configuration of a receiving module according to the second embodiment. The receiving module 20 is characterized in that a logical sum circuit 25 for generating an LOP signal is added to the configuration of FIG. 5 of the first embodiment.

  The OR circuit 25 is configured to take a logical sum (OR) of the light loss signals output from the O / E conversion circuit units 22A to 22D and output the logical value as an LOP signal.

  FIG. 9 shows the configuration of the O / E conversion circuits 22A to 22D in FIG. Here, since the O / E conversion circuits 22A to 22D have the same configuration, one of them will be described as the O / E conversion circuit 22, and the differential output data will be described as TMDS Data + and TMDS Data−.

  The O / E conversion circuit 22 is characterized in that the LOP detection unit 64 is provided in the O / E conversion circuit 22 of FIG. When the amount of incident light from the optical fiber 30 to the PD 61 is small, the output amplitude from the preamplifier 62 is substantially proportional to the amount of incident light. Therefore, the LOP detection unit 64 compares the output amplitude Ao of the preamplifier 62 with a predetermined threshold value As, and if As <Ao, it determines that the optical signal has reached the PD 61 and determines the Low output signal. If Ao <As, it is determined that the optical signal does not reach the PD 61, and a High output signal is generated. The threshold value As is set to a value greater than or equal to the amplitude due to the noise level.

  The reason why the amount of light incident on the PD 61 is small is, for example, that the optical signal does not reach due to disconnection or breakage of the optical fiber 30, or the LD 41 fails and does not emit light.

  The outputs of the LOP detection units 64 of the O / E conversion circuits 22A to 22D are input to the OR circuit 25 shown in FIG. When a high LOP signal is generated in any of the O / E conversion circuits 22A to 22D, a high output signal is generated in the OR circuit 25, and an abnormality is notified to the transmission module 10.

  FIG. 10 shows a configuration of a transmission module according to the second embodiment. The transmission module 10 includes a buffer circuit 16 that receives the LOP signal from the reception module 20 in the configuration of the transmission module 10 of FIG. 3 according to the first embodiment, and further, an error (ERR) is displayed on the operation display unit 10a. The configuration is characterized by the addition of the LED 15C as a third display element for display.

  The buffer circuit 16 receives the LOP signal transmitted from the receiving module 20 through the metal cable 40, and applies the output signal to the ERR LED 15C of the operation display unit 10a to light it. With this configuration, the operator can recognize that there is some abnormality in the transmission of the optical signal. The buffer circuit 16 can be omitted when the LOP signal is hardly deteriorated or the voltage drop is small and a sufficient current for driving the display LED can be secured, such as when the length of the metal cable is short.

  FIG. 11 shows the configuration of the E / O conversion circuits 12A to 12D in FIG. Here, since the E / O conversion circuits 12A to 12D have the same configuration, one of them will be described as the E / O conversion circuit 12, and the differential input data will be described as TMDS Data + and TMDS Data-.

  The E / O conversion circuit 12 includes a pull-down resistor 44 connected between the LOP signal input line and the ground in the E / O conversion circuit 12 of FIG. 4, and a laser shutdown controller 45 that controls the LD driver 42 by the LOP signal. There is a feature in the structure provided.

  When the LOP signal becomes High, that is, when an abnormality occurs in the receiving module 20, the laser shutdown controller 45 controls the LD driver 42 to stop the light emission of the LD 41 so that the laser light is not irradiated onto the optical fiber 30. To.

(Effect of the second embodiment)
According to the second embodiment, in addition to the effects of the first embodiment, the following effects can be obtained.
(A) By adding the LOP signal, the reception state of the optical signal in the receiving module 20 can be confirmed on the host 110 side by the ERR LED 15C of the operation display unit 10a.
(B) Since the LD driver 42 can be controlled by the laser shutdown controller 45 using the LOP signal, the light emission of the LD 41 can be stopped when an abnormality occurs on the receiving module 20 side. As a result, it is possible to prevent the laser light from leaking outside from locations other than the LD 41.
(C) Since the LOP signal in the E / O conversion circuit 12 uses the LOP signal for the operation display unit 10a, it is not necessary to prepare a separate signal line, so that an increase in cost can be avoided.

[Third Embodiment]
FIG. 12 shows an optical signal transmission apparatus according to the third embodiment of the present invention. In this embodiment, the operation display unit 10a is moved from the transmission module 10 to the vicinity of the host 110 such as a video transmission device in the first embodiment, and other configurations are the same as those in the first embodiment. It is the same. However, the configurations of the transmission module 10 and the reception module 20 and the transmission form through the metal cable 40 are the same as those in the second embodiment. Therefore, ERR display is performed by the LOP signal.

  The operation display unit 10a installed in the vicinity of the host 110 is connected to the transmission module 10 by a metal cable 10b.

  FIG. 13 shows a configuration of a transmission module according to the third embodiment. The configuration of FIG. 13 is obtained by attaching a 4-bit connector 10c to the transmission module 10 having the configuration shown in FIG. The connector 10c is connected to the buffer circuits 13 and 16, the DC 5V power source, and the ground. Further, a metal cable 10b is detachably coupled to the connector 10c. The metal cable 10b has LEDs 15A, 15B, and 15C and four leads connected to the ground. Instead of using the connector 10c, the end of the metal cable 10b may be directly connected to the buffer circuits 13 and 16, the power source and the ground.

(Effect of the third embodiment)
According to the third embodiment, in addition to the effects of the first and second embodiments, the following effects can be obtained.
(A) Since the operation display unit 10a can be installed in the vicinity of the host 110 such as the upper surface of the host 110, the operator of the host 110 can check the operation state of the optical signal transmission apparatus 1 at the installation location of the host 110.
(B) Since the operation display unit 10a can freely attach and detach the metal cable 10b to the connector 10c, the installation position of the operation display unit 10a can be freely changed by arbitrarily changing the length of the metal cable 10b.

[Other embodiments]
The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. For example, the metal cable 40 may be configured to use an optical fiber instead of this and perform signal conversion by an E / O conversion circuit and an O / E conversion circuit for transmission.

  The operation display unit 10a is configured to perform the abnormality by turning on the LED 15. However, if a display device such as a liquid crystal display is used, a warning message can be displayed. Since the message can display a plurality of contents, the contents of the abnormality can be accurately notified to the operator.

  It is also conceivable to use a personal computer (personal computer) as the host 110 and display a monitor screen similar to the screen that is output remotely by the operator. In this case, the operation display unit 10a can also use a confirmation monitor screen. That is, by pulling out a cable for outputting an operation display signal from the transmission module and inputting it to the host or confirmation monitor, the operation state can be confirmed by the operator. This eliminates the need to prepare the operation display unit 10a separately.

  Moreover, in said each embodiment, although LED was used for the display element of the operation | movement display part 10a, it is not limited to LED, For example, EL, an incandescent bulb, etc. may be sufficient.

  In addition, the constituent elements of the above embodiments can be arbitrarily combined without departing from the spirit of the present invention.

1 is a connection diagram illustrating an optical signal transmission device according to a first embodiment of the present invention. It is a figure which shows the structure of the transmission signal between the transmission module of FIG. 1, and a receiving module. FIG. 3 is a connection diagram illustrating a detailed configuration of the transmission module in FIG. 2. FIG. 4 is a connection diagram showing details of the E / O conversion circuit of FIG. 3. FIG. 3 is a connection diagram illustrating a detailed configuration of the reception module in FIG. 2. FIG. 6 is a connection diagram illustrating details of the O / E conversion circuit of FIG. 5. It is a connection diagram which shows the optical signal transmission apparatus which concerns on the 2nd Embodiment of this invention. It is a connection diagram which shows the structure of the receiving module which concerns on 2nd Embodiment. FIG. 9 is a connection diagram illustrating a configuration of the O / E conversion circuit of FIG. 8. It is a connection diagram which shows the structure of the transmission module which concerns on 2nd Embodiment. FIG. 11 is a connection diagram illustrating a detailed configuration of the E / O conversion circuit of FIG. 10. It is a connection diagram which shows the optical signal transmission apparatus which concerns on the 3rd Embodiment of this invention. It is a connection diagram which shows the structure of the transmission module which concerns on the said 3rd Embodiment. It is a connection diagram showing a video system using a metal cable. It is a connection diagram which shows the structure of the transmission signal in the DVI metal cable in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical signal transmission apparatus 10 Transmission module 10a Operation | movement display part 10b Metal cable 10c Connector 11 DVI connector 12, 12A, 12B, 12C, 12D E / O conversion circuit 13 Buffer circuit 13a, 13b, 13c Buffer 14 Internal switch 16 Buffer circuit 20 Receiving module 21 DVI connectors 22, 22A, 22B, 22C, 22D O / E converter circuits 23a, 23b, 23c Buffer 23 Buffer circuit 24 Internal switch 25 OR circuit 30 Optical fiber 40 Metal cable 41 LD (Laser diode)
42 LD driver 43 Laser power controller 44 Pull-down resistor 45 Laser shutdown controller 51A, 51B External power supply 61 PD (photodiode)
62 Preamplifier 63 Postamplifier 64 LOP Detection Unit 100 Video System 110 Host 120 Monitor 130, 130A, 130B Metal DVI Cable 130a Data Line 130b Control Line 130c GND Line Ao Output Amplitude As Threshold

Claims (12)

An optical transmitter for converting an image electrical signal transmitted from the host device into an image optical signal;
An optical receiver that converts the image optical signal transmitted from the optical transmitter via an optical transmission medium into an image electrical signal and outputs an image to an output device;
A transmission medium different from the optical transmission medium for transmitting a control signal between the host device and the output device;
An optical signal transmission device, comprising: a state display unit provided on an optical transmission side and detecting and displaying a state of the reception side from the control signal. An optical transmitter for converting an image electrical signal transmitted from the host device into an image optical signal;
An optical receiver that converts the image optical signal transmitted from the optical transmitter via an optical transmission medium into an image electrical signal and outputs an image to an output device;
A state signal transmitting unit that is provided on the optical receiving side and transmits a state signal indicating a state of the receiving side to the optical transmitting unit via another transmission medium different from the optical transmission medium;
An optical signal transmission apparatus, comprising: a state display unit provided on an optical transmission side and displaying a state of the reception side based on the state signal transmitted from the state signal transmission unit. The optical transmission medium is an optical fiber;
The optical signal transmission apparatus according to claim 1, wherein the other transmission medium is a metal cable.   The optical signal transmission device according to claim 1, wherein the status display unit displays the status on the receiving side based on a status signal output from the output device.   The optical signal transmission apparatus according to claim 1, wherein the state display unit displays the state on the reception side based on an optical reception state signal in the optical reception unit.   The optical signal transmission apparatus according to claim 4, wherein the status signal is an HPD (Hot Plug Detect) signal.   6. The optical signal transmission apparatus according to claim 5, wherein the optical reception state signal is a LOP (Loss Of Power) signal.   The status display unit includes a first display element driven by a power supply voltage being supplied to the optical transmission unit, and a second display element driven by an HPD (Hot Plug Detect) signal included in the status signal. The optical signal transmission device according to claim 4, further comprising:   The status display unit includes a first display element driven by a power supply voltage being supplied to the optical transmission unit, and a second display element driven by an HPD (Hot Plug Detect) signal included in the status signal. The optical signal transmission device according to claim 4, further comprising a third display element for abnormal display driven by a LOP (Loss Of Power) signal from the optical receiver.   The optical receiving unit includes a plurality of signal conversion circuits that individually photoelectrically convert each data transmitted from the optical transmission medium, and a plurality of optical signal state detection units that determine a reception state of the individual optical signals. And a logical sum circuit that takes a logical sum of the output signals of the plurality of signal state detectors and sends the result as an LOP (Loss Of Power) signal to the optical transmitter. Item 3. The optical signal transmission device according to Item 1 or 2.   The plurality of signal conversion circuits include a light receiving element that receives an optical signal and converts the light signal into an electrical signal, and an LOP detection unit that generates the LOP signal based on a comparison result between a light reception level of the light receiving element and a preset threshold value. The optical signal transmission device according to claim 10, comprising:   The optical signal transmission device according to claim 1, wherein the status display unit is installed in the vicinity of the optical reception unit or the host device.