JP4345652B2 - Digital video signal interface module - Google Patents

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, optical fiber is used for transmission of high-frequency digital video signals (Red, Green, Blue, Clock) of several hundred MHz to several GHz, and metal is used for transmission of DDC signals and HPD signals used at frequencies of 100 kHz or less. A technique that enables long-distance transmission at a relatively low cost by using a wire is known (see, for example, Patent Document 1).

  FIG. 3 is a diagram showing 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. 3, the transmission side of the module includes 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 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 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. . Further, 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 provided on the video output display device 2 side. Thus, + 5V power is supplied from the host device 1 side to the video output display device 2. 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, when an extension board such as a graphic card is mounted on the transmission side host device 1, a light emitting element in the transmission side plug connector 5 is provided. The photoelectric conversion means composed of the 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, power supply capacity is + 5V on the transmission side, not prescribed only with 50MA～1A, depending on the type of such graphics card is mounted, the power supply capacity is due to be insufficient.

In such a case, it is necessary to separately secure a power source capacity using an external power source. However, if the digital video signal interface module as shown in FIG. 3 is used as it is, the power supply line remains connected to the power supply terminal on the host device 1 side and power is supplied from the host device 1 side. In addition, when an external power supply is further connected, if there is a potential difference between the power supplied from the outside and the power supplied from the host device, power flows from the higher power supply to the lower power supply. It is necessary to avoid this.

  The present invention has been made in view of the above-described circumstances, and a digital video signal interface module that prevents power supply from the host apparatus side when an external power source is used to operate the photoelectric conversion means in the module. The issue is to provide

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. A plurality of metal lines includes at least the power supply line and a ground line, power supply line at the transmission side connector or receiver in the connector, connected to an external power source via one of the external power supply terminal Rutotomoni, video It is connected to the power supply terminal of the output display device, but is not connected to the power supply terminal of the host device. External power is supplied by connecting an AC adapter or a USB power cable.

  According to the present invention, the video signal is transmitted 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. Even in the case where the power supply capacity is insufficient, the photoelectric conversion means can be operated safely using an external power supply. Further, it is possible to perform signal transmission while maintaining a form conforming to the DVI standard without greatly changing the power supply or terminal device of the host device.

  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 part, 21 is a cable part, 22 is a connector body, 23 is a mounting screw, 24 is a hood, 25 is a cable jacket, 26, 26a and 26b are terminals for external power supply, 27 is an AC adapter, 27a Is a power plug, 28 is a USB power cable, and 28a is a power plug. Description of other reference numerals is omitted by using the same reference numerals 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 unit 20 includes, for example, a pair of mounting screws 23 for detachably connecting the connector main body 22 and includes a hood 24 that relaxes the bending of the introduction portion of the cable 21 unit.

In the present invention, at least one connector portion 20 is provided with a terminal 26a or 26b for connecting an external power source to an internal power line. The external power supply terminal 26a, for example, power plug 27a of the AC adapter 27 is provided so as to be connected from the rear of the connector body 22. Further, the external power supply terminal 26b, for example, power plugs 28a USB power cable 28 is provided so as to be connected from the rear of the connector body 22. The connector unit 20 may be configured to include either one of the external power supply terminals 26a and 26b, or may be configured to include a single common terminal structure to which both the power plugs 27a and 28a can be connected. Alternatively, both of the two external power supply terminals 26a and 26b may be provided, and either one may be selectively selected and used. Further, the external power supply terminals 26a and 26b are not limited to the rear portion of the connector main body 22, but can be provided on the side portions.

  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 supply 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.

  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 is normally supplied from the host device 1 side using a power line 13 connected to the power terminal of the DVI connector terminal 3 and a ground line 14 connected to the ground terminal. However, when an expansion board such as a graphic card is mounted on the transmission-side host device 1, the power capacity is insufficient, and the photoelectric conversion means including the light-emitting element unit 7 in the transmission-side plug connector 5 and the light reception in the reception-side plug connector 6. The photoelectric conversion means composed of the element unit 9 may not work. In such a case, the external power supply terminal 26 as shown in FIG. 1A is provided, and it is necessary to supply power to the power supply line 13 from the outside using a connector in which the external power supply terminal 26 is connected to the power supply line 13. There is.

  In the present invention, as a power source for the drive circuit device 8 and the amplification circuit device 10, an external power source is taken in from the transmission side plug connector 5 or the reception side plug connector 6 and supplied to the power supply line 13, and this is used. Yes. However, if the external power supply is connected while the power supply line 13 is connected to the power supply terminal of the DVI connector terminal 3 of the host device 1 and there is a potential difference between the power supply of the host device 1 and the external power supply, the higher potential is applied. Power flows into 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 connected to the power terminal of the DVI connector terminal 4 of the video output display device 2 as shown in FIG. However, the power supply terminal of the DVI connector terminal 3 of the host device 1 is not connected. Specifically, a part of the power supply line 13 may be cut and cut so that the power supply line 13 is not connected to the terminal of the transmission side plug connector 5 connected to the power supply terminal (14th pin) of the host device 1.

  However, it is preferable to use a short-circuit member that can be attached to and detached from the cut-and-removed portion, an openable / closable member that can be operated from the outside, and the like so that connection and non-connection can be easily selected. As a result, when power supply from the host side becomes necessary, it can be easily changed. When the transmission side plug connector 5 is provided with the external power supply terminal 26 and an external power source is connected to the transmission side plug connector 5, the connection is automatically performed by the connection operation of the power plug of the external power source. The connection with the power supply terminal of the host device 1 may be cut off.

  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. Thereby, the HPD function can be used regardless of whether or not the power supply to the power supply line 13 is performed from the host device 1 side.

  As the external power source, an AC adapter 27 that converts a normal 100V AC power source into a DC power source having a predetermined voltage can be used. This AC adapter 27 is used to obtain a + 5V DC output, and is connected to an external power supply terminal 27a on either the transmission side plug connector 5 or the reception side plug connector 6 and connected to a power line in the module. 13 is fed. Alternatively, a USB power cable 28 may be used as an external power source, and a +5 V power source may be obtained from a USB terminal of an information device or the like at hand. As the information device at hand, the host device 1 or the video output display device 2 may be used. The USB power cable 28 is also connected to either the transmission side plug connector 5 or the reception side plug connector 6.

  As described above, in the present invention, the transmission side plug connector 5 of the digital video signal interface module is connected to the external power supply while the power supply line 13 is not connected to the power supply terminal of the host device 1. As a result, the driving circuit device 8 that drives the light emitting element unit 7 by the external power source and the amplification circuit device 10 that amplifies the output of the light receiving element unit 9 can be operated with peace of mind, and power supply to the video output display device 2 is ensured. can do. Furthermore, the present invention can be easily implemented without substantially changing the existing connector shape, cable shape, wiring form, and the like.

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 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 ... Connector part, 21 ... Cable part, 22 ... Connector body, 23 ... Mounting screw, 24 ... Hood, 25 ... Cable jacket, 26, 26a, 26b ... External power supply terminal, 27 ... AC adapter, 28 ... USB power cable, 27a, 28a ... Power plugs.

Claims (4)

A transmission-side connector provided with conversion means for converting a digital video signal input from a host device into an optical signal, and a reception-side connector provided with conversion means for converting the optical signal into an electrical 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,
Wherein comprising a plurality of metal lines and at least the power supply line to the ground line, the power line is at the transmission side connector or receiver in the connector, Ru is connected to an external power source via one of the external power supply terminal The digital video signal interface module is connected to a power supply terminal of the video output display device but is not connected to a power supply terminal of the host device.   2. The digital video signal interface module according to claim 1, wherein an AC adapter is connected to the power line.   The digital video signal interface module according to claim 1, wherein a USB power cable is connected to the power line.   The digital video signal interface module according to claim 1, wherein the power line is connected to a hot plug detection terminal (HPD terminal) of a host device.

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