KR200390509Y1 - Signals transmission system for display - Google Patents

Abstract

The signal transmission system between the signal processing stations 1, 11 and the displays 8, 18 is connected with the signal connections 2, 3, 4, 5, 6, 15 from the stations 1, 11 to the display. At least one return from the display 8, 18 to the station 1, 11. According to the present invention, the signal connection part 2, 3, 4, 5, 6, 15 between the station 1, 11 and the display 8, 18 may include one or more optical fibers 14. 15, wherein the signal connections 2, 3, 4, 5, 6, 15 are connected to the display 18 and at least one channel for transmitting signals from the station 11 to the display 18. At least one channel in the cable 15 which transmits signals to the station 11 to obtain the return channel.

Description

Signal transmission system for display {SIGNALS TRANSMISSION SYSTEM FOR DISPLAY}

The present invention relates to a signal transmission system that transmits a signal between a signal processing station and a display, comprising a signal connection from the station to the display and at least one return line from the display to the station.

Assume the use of retro-projection or front projection screens with flat screen, liquid crystal display (LCD) and LCD, digital light processing (DLP) and liquid crystal on silicon (LCoS) technologies using so-called plasma technology, It is increasingly spreading in public places and professional research. In the following, a set containing circuitry associated with the screen will be generally called a display.

The digital signal needed to drive the display is processed at the appropriate station and serial bus (such as the IEEE 1394 bus, or Firewire) which somehow provides the use of some shielded coaxial cable or so-called twisted pairs. Or to a display by a Digital Visual Interface (DVI) semi-serial transmission.

Data is also sent from station to display and from display to station for setup, control and setup during installation; The data sent from the display to the station represents a so-called return channel.

In particular, the return channel is both a signal requested by the station from the display for the purpose of control (such as the state of some drive system registers) and coded control transmitted by the user via a keyboard located on the display, and / or remotely. Control. The cables are often very bulky, especially when used in homes or public places; Moreover, due to the significantly longer distance (several tens of meters) between the station and the display, the transmitted signal can be significantly attenuated and / or lowered by the interference generated by the cable, thus degrading the image quality.

Sony has proposed a system architecture by providing a transmission system that provides video signal transmission to the display using shielded twisted pair cables having a diameter of 5 mm and equalizers in the display to compensate for the attenuation caused by the cables. Complicated. Recently, Sony has proposed a version of the system in which signal transmission from the station to the display is by optical fiber. However, such a system does not provide signal transmission from the display to the station.

It is an object of the present invention to solve the above drawbacks and to reduce the cable volume to avoid signal distortion at the same time, and to provide a system for transmitting digital signals between the station and the display providing a return channel.

In order to achieve this object, it is an object of the present invention to provide a digital signal transmission system having the features described in the appended claims, which form an integral part of the description herein.

Further objects, features and advantages of the present invention will become apparent from the following detailed description and the accompanying drawings, which are provided by way of non-limiting examples.

1 schematically illustrates a known semi-serial transmission system; The block labeled 1 with reference to FIG. 1 represents a data processing station receiving a plurality of digital signals transmitted to a display; For example, the figures show video signals for three colors (R, G, B), horizontal and vertical synch (H and V), respectively, and a clock signal used for the control and setting of the display 8 as mentioned previously. (CLOCK) and data line DATA are shown.

The signals are converted in parallel in series at station 1 and then appropriately multiplexed to reduce the plurality of connecting lines to display 8. For example, FIG. 1 shows five outgoing lines, denoted by reference numerals 2 to 6 from station 1, respectively, and the appropriately multiplexed lines 2, 3, and 4 represent video signals R, G, B and synchronization. Carries (H and V); Line 5 carries a clock signal CLOCK and signal line 6 carries a data signal DATA. The signal is received by the interface 7 in which the signals of lines 2 to 6 are demultiplexed and converted in an optimal form for driving the display indicated by reference numeral 8. 1 reproduces the incoming signal to the station 1. Of course, other signals not shown here may also be present in the retraction of the station 1 when specifically required by the technology used in the display.

As mentioned above, the connecting lines 2 to 6 consist of shielded coaxial cables or twisted pairs, often very bulky; In the case of long connections, they can cause significant degradation in the signal because of the attenuation that can be caused.

According to the present invention, the connection between the station and the display is only made by a cable comprising one or more optical fibers, which are subsequently called optical cables. Fiber optics actually have the following beneficial features:

-Small size and weight;

Not sensitive to electromagnetic interference;

-Spicy low attenuation;

High bit rate operation (over 2 Gb / s).

Moreover, this selection is advantageous as it can transmit several independent signals, i.e. several channels using a light emitting source having that particular wavelength for each channel, using one single optical fiber.

2 shows a signal transmission system according to the present invention. Therefore, the signal processing station indicated by reference numeral 11 is a video signal (R, G, B), one or more synchronization signals, SYNC, clock signal (CLOCK), data signal (DATA), and finally not shown in the figure It is indicated within the hatching line reached by the digital incoming signal containing another particular signal. The station 1 comprises a formatting block 12, which is converted in series in parallel with the control signal DATA1 necessary for the control and setting of the display 18, and then multiplexed to form the formatting block 12. Form a single serial flow 31 emitted at The block denoted by reference numeral 13 is an electric / optical converter for converting an electrical signal carrying the serial flow 31 emitted from the formatting block 12 into an appropriately modulated light emission signal 32 with a predetermined wavelength. Indicates. As is known, all-optical converters can be obtained using lasers or LED diodes. The light emission signal 32 is continuously transmitted to the optical fiber 14 contained in the cable 15 connecting the station 11 to the display 18. On the same optical fiber 14, the station 11 is transmitted by the display 18 and receives a serial signal 33 carried by a light emitting source, in particular a laser having a wavelength different from that used by the converter 13. do; In other words, the signal transmitted by the station 11 to the display 18 and the signal transmitted by the display 18 to the station 11 are carried on the same optical fiber 14 but carried on two different channels. The optical signal from the display 18 is transmitted to an optical / electric converter 16, where it is converted into an electrical signal DATA2. This electrical signal DATA2, which represents the so-called return channel, contains the data relating to the drive of the display and the coded control transmitted by the user as described above. Photoelectric converters can be obtained using photodiodes or phototransistors. The signal of the return channel is finally demultiplexed in the demultiplexer block 17, and then in the microprocessor indicated by reference numeral 28, which also transmits the signal DATA1 necessary for the control and setting of the display 18 described previously. Is processed.

Display 18 within hatched line includes screen 23 and associated circuitry, which will be described in further detail below.

The optical signal from block 13 comprising the video signals R, G, B, sync SYNC, clock signal CLOCK, and control signal DATA1 for setting and control converts it into a serial electrical signal. Is sent to the photoelectric converter indicated at 20; The signal is demultiplexed in the block labeled 21 and then returned to its original form directly available by the drive circuit 22 activating the screen 23 of the display 18.

The multiplexer block, denoted 24, receives data from the drive circuit 22 via line 25, such as content information in a particular register, and coded control transmitted by the user via the keyboard, denoted 26. It should be noted that the user may also transmit control by remote control not shown in FIG. The signal is then multiplexed into the multiplexer block 24 with the signal DATA2 previously described at the emission. The electrical signal DATA2 is converted into an optical signal in the all-optical converter indicated by reference numeral 27 and then transmitted to the block 16 of the station 11 via the optical fiber 14 included in the cable 15.

It is appropriate to match the photoelectric converters 16 and 20 with the optical separator filter at the inlet, and each of them receives only the optical signals with wavelengths on their own channels to avoid mixing the signals of both channels.

The advantages of the signal transmission system between the signal processing station and the display according to the present invention are apparent from the above description.

Advantageously, by way of example, the diameter of the cable with the optical fiber is smaller than 2 mm, ie its volume is significantly reduced.

It should be noted that an optical cable can be easily hidden, such as placing it in a duct carrying current; This is possible because the signal carried by the optical cable is free from electrical and / or electromagnetic interference.

 Moreover, because the attenuation produced by the optical cable is so low, the use of an equalizer in the display that advantageously returns the signal to a suitable level is no longer necessary because of the resulting abundant stockpile.

It is apparent that many changes can be made to the signal transmission system according to the present invention without departing from the technical spirit of the present invention.

For example, if one wishes to reduce the bit rate to simplify the multiplexing operation, the signal sent to the display may be carried on more than one channel; On the other hand, it should be noted that since the signal transmitted to the station generally has a low bit rate, high bit rate problems do not usually exist for the return channel, so that only one channel is quite sufficient.

Moreover, if one wishes to simplify the photoelectric converter and remove the optical separator filter, an optical fiber can be used for each channel; For example, an optical cable having three optical fibers having a diameter of approximately 3.5 mm can be used: two optical fibers carry a signal to the display and one optical fiber is used for the return channel.

The present invention has the effect of reducing the cable volume and at the same time avoiding signal distortion.

1 shows a known signal transmission system,

2 shows a signal transmission system according to the present invention.

Claims (11)

In the signal transmission system between the signal processing stations (1, 11) and the display (8, 18), Signal connections (2, 3, 4, 5, 6, 15) from the stations (1, 11) to the display; At least one return line from the display (8, 18) to the station (1, 11), The signal connection 2, 3, 4, 5, 6, 15 between the station 1, 11 and the display 8, 18 is obtained by a cable 15 comprising one or more optical fibers 14. under, The signal connections 2, 3, 4, 5, 6, 15 have at least one channel for transmitting signals from the station 11 to the display 18 and from the display 18 to the station 11. At least one channel in the cable 15 for transmitting signals to obtain the return channel, The at least one channel for transmitting signals from the station 11 to the display 18 and the at least one channel for transmitting signals from the display 18 to the station 11 are carried to an optical fiber 14. Signal transmission system characterized in that. The method of claim 1, The system uses a plurality of electric / optical converters (13, 17) obtained by a laser. The method of claim 1, The system uses a plurality of all-optical converters (13, 17) obtained by LED diodes. The method of claim 1, The system uses a plurality of optical / electric converters (16, 20) obtained by a photodiode. The method of claim 1, The system uses a plurality of photoelectric converters (16, 20) obtained by phototransistors. The method according to claim 4 or 5, Each photoelectric converter (16, 20) comprises an optical separator filter. The method of claim 1, The display (18) is characterized in that it uses plasma technology. The method of claim 1, The display (18) is characterized in that it uses Liquid Crystal Display (LCD) technology. The method of claim 1, The display (18) is characterized in that it uses retro or front projection with LCD technology. The method of claim 1, The display (18) is characterized in that it uses retro or front projection with DLP (Digital Light Processor) technology. The method of claim 1, The display (18) is characterized in that it uses retro or front projection with Liquid Crystal on Silicon (LCoS) technology.