JP2006058549A - Digital video signal interface module - Google Patents

Abstract

Provided is a digital video signal interface module that prevents power supply from a host device side when a photoelectric conversion means in the module is operated using a power source on a video output display device side.
A transmission side connector having a conversion means for converting a digital video signal inputted from a host device into an optical signal, and a conversion means for converting the optical signal into an electric signal and outputting the electric signal to a video output display device. Is connected to a plurality of optical fibers 12 and a composite cable composed of a plurality of metal wires. The plurality of metal lines include at least a power supply line 13 and a ground line 14, and the power supply line 13 is connected to the power supply terminal of the video output display device 2 and is not connected to the power supply terminal of the host device 1. By connecting the receiving side connector 6 to the input terminal device 4 of the video output display device 2, an operating means for enabling the power supply to the power supply line 13 is provided.
[Selection] Figure 2

Description

  The present invention relates to a digital video signal interface module used for receiving a digital video signal transmitted from a host device such as a computer and displaying it on a video output display device such as a liquid crystal display device.

  In recent years, a video signal has been displayed in a large size on a display device such as a liquid crystal display (LCD) or a plasma display (PDP) or a display device using a projector. In addition, digitalization of video signals enables high-quality video transmission, which can be used not only as a television receiver, but also for advertising, medical equipment, trains, department stores, etc. and display means for various information transmission It has come to be used as.

  Signal transmission between such a video output display device and a host device (for example, a video signal source such as a computer, a display controller,...) Is a DVI that does not convert a digital signal into analog but transmits it in a digital format. The method using the (Digital Visual Interface) standard has become the mainstream. Further, in this DVI system, information on the video output display device on the receiving side is transmitted to the host device on the transmitting side, and a DDC (Display Data Channel) function for plug and play, insertion / removal check in the power-on state, etc. Hot plug detection (Hot Plug Detect, hereinafter referred to as HPD) function and the like are included.

  In addition, video output display devices are increasingly used in places where the distance from a host device that supplies video signals is increased due to their versatility and size. However, if a digital signal is transmitted using a metal cable, the influence of attenuation or reflection of the transmitted video signal is large, and the cable length used between the video output display device and the host device is, for example, 5 m or less. Subject to such restrictions. Therefore, for transmission of high-frequency digital video signals (Red, Green, Blue, Clock) of several hundred MHz to several GHz, an optical fiber is used, and for transmission of DDC signals and HPD signals used at a frequency of 100 kHz or less. A technique that enables long-distance transmission at a relatively low cost by using a metal wire is known (see, for example, Patent Document 1).

  FIG. 4 is a diagram illustrating an example of a digital video signal interface module using the above-described conventional optical fiber and metal wire. In the figure, 1 is a host device, 2 is a video output display device, 3 and 4 are DVI connector terminals, 5 is a transmission side plug connector, 6 is a reception side plug connector, 7 is a light emitting element unit, 8 is a drive circuit device, 9 Is a light receiving element unit, 10 is an amplifier circuit device, 11 is a composite cable, 12 is an optical fiber, 13 is a power line, 14 is a ground line, 15 and 16 are metal wires for DDC signals, and 17 is a resistance element for HPD. Show.

  As shown in FIG. 4, the transmission side of the module is composed of a transmission side plug connector 5 connected to a DVI connector terminal 3 provided in a host apparatus 1 such as a computer to which a digital video signal is inputted. The receiving side of the module is composed of a receiving side plug connector 6 connected to a DVI connector terminal 4 provided in various video output display devices 2 such as a liquid crystal display, a plasma display or a projector for displaying an image of a digital video signal. The The DVI connector terminals 3 and 4 are connector terminals designed to satisfy the DVI system. In addition to the digital video signal transmission terminals (R, G, B, Clock), the DVI connector terminals 3 and 4 are connected to the video output display device 2 on the receiving side. A DDC clock, a DDC data terminal, an HPD terminal, and the like for transmitting information to the host device 1 on the transmission side are provided.

  The transmission-side plug connector 5 includes a light emitting element unit 7 such as a semiconductor laser and a drive circuit device 8 for converting a digital video signal from the host device 1 from an electric signal to an optical signal and transmitting it. . The receiving side plug connector 6 includes a light receiving element unit 9 such as a photodiode and an amplifier circuit device 10 for restoring a digital video signal received as an optical signal into an electric signal. The transmission side plug connector 5 and the reception side plug connector 6 are connected by a composite cable 11 having four optical fibers 12 for transmitting digital video signals and at least two metal wires of a power line 13 and a ground line 14. Yes. In the composite cable 11, DDC signal metal wires 15 and 16 are also housed as an integral structure so as to be connected by the transmission side plug connector 5 and the reception side plug connector 6.

  The power line 13 is connected to the power terminal (14th pin) of the DVI connector terminal 3 provided on the host device 1 side, and the ground line 14 is connected to the ground terminal (15th pin) of the DVI connector terminal 3. . The power supply line 13 and the ground line 14 are similarly connected to the power supply terminal (14th pin) and the ground terminal (15th pin) of the DVI connector terminal 4 provided on the video output display device 2 side. A DC power supply of +5 V is supplied to the video output display device 2 from the 1 side. The video output display device 2 includes, for example, an EEPROM (Electrically Erasable and Programmable ROM) which is a kind of nonvolatile memory in which information such as image resolution information and refresh rate is written. For the drive, a power supply on the host apparatus 1 side fed through the power supply line 13 is used.

Further, the power line 13 and the ground line 14 are also connected to the drive circuit device 8 in the transmission side plug connector 5 and the amplification circuit device 10 in the reception side plug connector 6, and are used in the video output display device 2. Electric power is used as the operating power source. The HPD signal can be taken into the host device 1 from the power supply line 13 via the resistance element 17.
JP 2002-366340 A

  When a power supply function from the transmission side is used using a DVI connector terminal and a cable conforming to the DVI standard, light emission in the transmission side plug connector 5 may be caused depending on the type of graphic card or the like mounted on the host device 1 on the transmission side. The photoelectric conversion means composed of the element unit 7 and the photoelectric conversion means composed of the light receiving element unit 9 in the receiving side plug connector 6 may not operate. This is because the DVI standard only defines the power supply capacity on the transmission side as +5 V, 50 mA to 1 A, and the power supply capacity may be insufficient depending on the type of the mounted graphic card or the like. In such a case, it is necessary to ensure the power capacity by using an external power source such as an AC adapter.

  On the other hand, on the video output display device 2 side, there is a case where power for driving the EEPROM or other main body accessory device is built in and power supply from the transmission side is not required. In the case of such usage, the power supply built in the video output display device 2 side is used as the power supply for the drive circuit device 8 in the transmission side plug connector 5 and the amplification circuit device 10 in the reception side plug connector 6. Thus, it is conceivable to solve the shortage of power supply capacity on the host device 1 side. However, if the module as shown in FIG. 4 is used as it is, if there is a potential difference between the power supplied from the host device 1 side and the power supplied from the video output display device 2 side, the higher power supply Since power flows into the lower power supply, this must be avoided.

  The present invention has been made in view of the above-described circumstances, and prevents power supply from the host device side when the photoelectric conversion means in the module is operated using the power source on the video output display device side. An object is to provide a digital video signal interface module.

  A digital video signal interface module according to the present invention includes a transmission-side connector having conversion means for converting a digital video signal input from a host device into an optical signal, and converts the optical signal into an electrical signal and outputs the electrical signal to a video output display device. The receiving side connector provided with the converting means is connected by a composite cable composed of a plurality of optical fibers and a plurality of metal wires. The plurality of metal lines include at least a power supply line and a ground line, and the power supply line is connected to the power supply terminal of the video output display device and is not connected to the power supply terminal of the host device. In addition, an operating means for enabling power supply to the power supply line when the receiving side connector is connected to the input terminal device of the video output display device is provided.

  According to the present invention, the power source of the video output display device is used to transmit the video signal from the transmission-side host device to the reception-side video output display device via the photoelectric conversion means in the digital video signal interface module. Thus, the photoelectric conversion means can be operated. As a result, even if the power supply capacity supplied from the host device on the transmission side is insufficient, it is not necessary to use an external power supply, and DVI can be used without major changes in the power supply or terminal device of the host device. Signal transmission can be performed while maintaining a form conforming to the standard. In addition, it is possible to arbitrarily select whether or not to use the power source of the video output display device, and the degree of freedom of use can be expanded.

  Embodiments of the present invention will be described with reference to the drawings. 1A is a diagram for explaining an example of the external shape of a digital video signal interface module, FIG. 1B is a diagram for explaining an example of a composite cable, and FIG. 2 is an example of the configuration of a digital video signal interface module according to the present invention. FIG. In the figure, 20 is a connector portion, 21 is a cable portion, 22 is a connector body, 23 is a mounting screw, 24 is a boot, and 25 is a cable jacket. The other reference numerals are the same as those used in FIG.

  The digital video signal interface module according to the present invention has connector portions 20 at both ends of a cable portion 21. One connector portion 20 is a transmission side plug connector 5 connected to a host device such as a computer, and the other connector portion 20 is a reception side plug connector connected to a video output display device such as a liquid crystal display or a projector display. 6. The connector part 20 includes, for example, a pair of mounting screws 23 for detachably connecting the connector main body 22 and has a boot 24 that relaxes the bending of the introduction part of the cable 21 part.

  As shown in FIG. 1 (B), for example, a cable unit 21 in which four optical fibers 12 and four metal wires are stored together is used. The metal line is composed of a power line 13, a ground line 14, and shielded electric wires 15 and 16 for DDC. In addition, the number of optical fibers and metal wires in the cable can be increased as necessary. However, in the digital video signal interface module of the present invention, at least four optical fibers 12 for video signal transmission and power lines A wire having two metal wires 13 and a ground wire 14 is used. When the cable length is short, a shielded wire may not be used for DDC. However, since the use at a maximum of 100 kHz is considered, it is preferable to use a shielded wire to suppress signal attenuation.

  As shown in FIG. 2, the basic configuration of the digital video signal interface module according to the present invention is the same as that described in FIG. That is, the transmission side of the module is configured by a transmission side plug connector 5 connected to a DVI connector terminal 3 provided in a host device 1 such as a computer to which a digital video signal is input. The receiving side of the module is composed of a receiving side plug connector 6 connected to a DVI connector terminal 4 provided in various video output display devices 2 such as a liquid crystal display, a plasma display or a projector for displaying an image of a digital video signal. The

  The DVI connector terminals 3 and 4 are connector terminals designed so as to realize the DVI standard signal transmission system, and, for example, a 24-pin receptacle shape is used. The DVI connector terminals 3 and 4 include a power terminal (14th pin), a ground terminal (15th pin), and a video on the receiving side, in addition to terminals (R, G, B, Clock) for digital video signal transmission. A DDC clock (No. 6 pin), a DDC data terminal (No. 7 pin), an HPD terminal (No. 16 pin), etc. for transmitting information of the output display device 2 to the host device 1 on the transmission side are provided.

  The transmission-side plug connector 5 includes a light emitting element unit 7 such as a semiconductor laser and a drive circuit device 8 for converting a digital video signal from the host device 1 from an electric signal to an optical signal and transmitting it. Yes. In the receiving side plug connector 6, in order to restore the digital video signal received in the form of the optical signal sent from the light emitting element unit 7 into an electric signal, the light receiving element unit 9 such as a photodiode and its amplification circuit device 10 are provided. have.

  The transmission-side plug connector 5 and the reception-side plug connector 6 described above have at least four optical fibers 12 that transmit digital video signals in the form of optical signals, and two metal wires that are a power line 13 and a ground line 14. They are connected by a composite cable 11. In addition, in the composite cable 11, metal wires (shielded wires) 15 and 16 for DDC signals are also housed as an integral structure so as to be connected by the transmission side plug connector 5 and the reception side plug connector 6. .

  The power line 13 is normally connected to the power terminal (14th pin) of the DVI connector terminal 3 on the host device 1 side, and the ground line 14 is connected to the ground terminal (15th pin). The power line 13 and the ground line 14 are similarly connected to the power terminal (14th pin) and the ground terminal (15th pin) of the DVI connector terminal 4 on the video output display device 2 side. A + 5V DC power supply is supplied to the output display device 2. The EEPROM mounted on the video output display device 2 side is operated by the power supplied from the host device 1 side. However, there is a use form in which a built-in power supply is provided on the video output display device 2 side and the power supply on the host device 1 side is not used as the power supply for the above-described EEPROM or other main body attachment device.

  The drive circuit device 8 that drives the light emitting element unit 7 and the amplifier circuit device 10 that amplifies the output of the light receiving element unit 9 require a power source for their operation. This power may be supplied using an external power source such as an AC adapter, but is usually connected from the host device 1 side to the power line 13 connected to the power terminal of the DVI connector terminal 3 and to the ground terminal. It is supplied using the ground line 14. However, when the video output display device 2 on the receiving side incorporates a power source for driving an EEPROM or other device attached to the main body, the power source on the video output display device 2 side is not used without using the power source on the host device 1 side. It is also possible to drive the drive circuit device 8 and the amplifier circuit device 10 using.

  In the present invention, the power supply on the video output display device 2 side is used as the power supply for the drive circuit device 8 and the amplifier circuit device 10. However, if the power supply line 13 is connected to the power supply terminal of the DVI connector terminal 3 of the host device 1 and also connected to the power supply of the video output display device 2 side, the power supply of the host device 1 side and the video output display device 2 side are connected. If there is a potential difference with the power source, power flows from the higher potential to the lower side, resulting in unnecessary power consumption.

  Therefore, in the present invention, in the transmission side plug connector 5 of the existing digital video signal interface module, the power line 13 is not connected to the power terminal of the DVI connector terminal 3 of the host device 1. Specifically, a part of the power supply line 13 may be cut and cut off at the terminal of the transmission-side plug connector 5 connected to the power supply terminal (14th pin) of the host device 1. Moreover, it is good to set it as the structure which can select a connection and non-connection easily using the short-circuit member which can attach or detach this fracture cutting part, the opening / closing member which can be operated from the outside, etc. As a result, when power supply from the host side becomes necessary, it can be easily changed.

  Even when the power supply line 13 is not connected to the power supply terminal (14th pin) of the host device 1, the hot plug detection HPD terminal (16th pin) is connected via the resistance element 17. It is desirable to keep the power line 13 connected. Accordingly, the HPD function can be used regardless of whether the power supply to the power supply line 13 is from the video output display device 2 or the host device 1 side. Note that the built-in power supply on the video output display device 2 side is not necessarily supplied to the power supply terminal (14th pin) to which the power supply line 13 is connected. In this case, the power is connected to the empty terminal (including pins not used in the single link) of the DVI connector terminal 4 so that power is supplied to the power line 13 in the receiving side plug connector 6. To.

  FIG. 3A is a diagram showing another embodiment of the connector portion, which is suitable for use as the receiving side plug connector 6. The connector portion 20 ′ has a shape in which, for example, a protruding portion 22a is formed on the side of the connector main body 22, and a stud-like actuating member 26 is provided on the protruding portion 22a. 1 and the configuration described in FIG.

  On the other hand, on the video output display device 2 on the receiving side, as shown in FIG. 3B, an operation switch 27 for enabling the above-mentioned built-in power supply to be supplied to an external device is provided with a DVI connector as an input terminal device. It is installed near the terminal 4. When the receiving side plug connector 6 is connected, the operation switch 27 is turned on by the actuating member 26 so that the built-in power of the receiving side video output display device 2 is automatically supplied to the power line 13 through the power terminal. it can.

  The actuating member 26 need not have a stud-like protruding shape. For example, if the counterpart operation switch 27 has a structure protruding in a stud shape, the actuating member 26 can be shaped so as not to protrude forward. As the receiving side plug connector 6 shown in FIG. 2, when the receiving side video output display device 2 has a built-in DC power source, the DC power source on the video output display device 2 side is used. The power supply line 13 can be automatically supplied.

  In the above configuration, the power supply line 13 is not connected to the power supply terminal of the host device 1 as the transmission side plug connector 5 constituting the digital video signal interface module, and the reception side plug connector 6 is as shown in FIG. The one having the actuating member 26 is used. By using the digital video signal interface module having such a configuration, the power supply line 13 is automatically selected to be supplied with power from the video output display device 2 on the receiving side, and the power supply from the host device 1 is cut off. . As a result, the drive circuit device 8 that drives the light emitting element unit 7 and the amplifier circuit device 10 that amplifies the output of the light receiving element unit 9 are operated by the power supply from the video output display device 2.

  Further, there is a case where the power supply capacity of the expansion board of the graphic card originally mounted on the host device 1 side is insufficient, and the drive circuit device 8 and the amplifier circuit device 10 cannot be operated. Even in such a case, by switching to the power source from the video output device 2 side using the digital video signal interface module described above, the connector shape, cable shape, wiring form, etc. can be substantially reduced without using an external power source. It is possible to easily secure a power source necessary for operating the drive circuit device 8 and the amplifier circuit device 10 without changing to the above.

It is a figure explaining the outline and cable structure of the digital video signal interface module made into the object of this invention. It is a figure explaining an example of a structure of the digital video signal interface module by this invention. It is a figure explaining an example of the receiving side plug connector suitable for using with the digital video signal interface module by this invention. It is a figure explaining the example of the conventional digital video signal interface module.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Host device, 2 ... Video output display device, 3, 4 ... DVI connector terminal, 5 ... Transmission side plug connector, 6 ... Reception side plug connector, 7 ... Light emitting element unit, 8 ... Drive circuit device, 9 ... Light receiving element Unit: 10 ... Amplification circuit device, 11 ... Composite cable, 12 ... Optical fiber, 13 ... Power supply line, 14 ... Ground line, 15, 16 ... Metal wire (shield wire) for DDC, 17 ... HPD resistance element, 20, 20 '... connector part, 21 ... cable part, 22 ... connector body, 22a ... projecting part, 23 ... mounting screw, 24 ... boot, 25 ... cable jacket, 26 ... operating member, 27 ... operation switch.

Claims (2)

A transmission-side connector having conversion means for converting a digital video signal input from a host device into an optical signal, and a reception-side connector having conversion means for converting the optical signal into an electric signal and outputting it to a video output display device Is a digital video signal interface module in which a plurality of optical fibers and a composite cable composed of a plurality of metal wires are connected,
The plurality of metal lines include at least a power line and a ground line, and the power line is connected to a power terminal of the video output display device and is not connected to a power terminal of the host device. Video signal interface module.   2. The digital video according to claim 1, further comprising operating means for enabling power supply to the power supply line when the receiving connector is connected to an input terminal device of the video output display device. Signal interface module.

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