JP5534968B2 - Liquid crystal display device and electronic information device - Google Patents

Description

  The present invention relates to a liquid crystal display device and an electronic information device, and in particular, a liquid crystal display device using a signal transmission method for reducing EMI (Electro Magnetic Interference) noise as a video signal transmission method and such a liquid crystal display device. It relates to electronic information equipment.

  Conventionally, various video display apparatuses use various video signal transmission schemes to transmit video signals.

  For example, in the past, it was common to install a signal line for each signal when transmitting and receiving video signals. However, this technique has a problem in terms of cost and physical installation area due to the increase in signal lines. It was.

  In order to solve this, several methods are known in which a plurality of video signals and clock signals are multiplexed to reduce the number of signal lines.

  FIG. 9 is a diagram for explaining a conventional liquid crystal display device using such a method.

  The liquid crystal display device 200 receives a video signal Vs, outputs a timing signal CL and a data signal D, and outputs a timing controller 201 that outputs a scanning signal Cs, a liquid crystal panel 204 that displays an image, and a timing signal CL. A source driver 202 that drives a signal line of the liquid crystal panel based on the data signal D and a scanning driver 203 that drives a scanning line of the liquid crystal panel 204 based on the scanning signal Cs are provided.

  FIG. 10 is a block diagram showing a specific configuration of the timing controller 201 and the source driver 202.

  The timing controller 201 receives a digital video signal Vs, separates a data signal and a clock signal included in the digital video signal, and converts them into 8-bit coded signals, and 8 converted from the data signal. An 8b / 10b encoder that converts a bit-coded signal into a 10-bit coded signal, a 10-bit coded signal into a serial signal, and an 8-bit coded signal as a data signal into a serial signal, The serializer 14 outputs the serial data signal D and a pair of clock signals CL to the transmission line L.

  The source driver 202 receives a pair of serial data signals D and a pair of clock signals CL output from the serializer 14 via a transmission line L, and these signals are a 10-bit coded signal and a clock signal as data signals. A deserializer 21 for converting into an 8-bit coded signal, an 8b / 10b decoder 22 for converting a 10-bit coded signal as a data signal into an 8-bit coded signal, an 8-bit coded signal and a clock as a data signal It has a command decoder 24 that converts an 8-bit coded signal as a signal into a drive signal Ds for the liquid crystal panel and applies it to the data line of the liquid crystal panel 204.

  Next, the operation will be described.

  In the liquid crystal display device 200 having such a configuration, when the digital video signal Vs is input, the timing controller 201 outputs the data signal D and the clock signal CL to the source driver 202 based on this signal, and also the scanning signal. Cs is output to the scan driver 203. When the data signal D and the clock signal CL are input to the source driver 202 and the scanning signal Cs is input to the scanning driver 203, the source driver 202 outputs a data line driving signal to the data line of the liquid crystal panel 204, and scans. The driver 203 outputs a scanning line driving signal to the scanning line of the liquid crystal panel 204. As a result, the liquid crystal panel 204 displays an image corresponding to the input video signal Vs.

  At this time, in the timing controller 201, each of the data signal and the clock signal included in the video signal Vs input by the command encoder 11 is separated and converted into an 8-bit coded signal, and the 8-bit coded signal is generated as the data signal. The signal is converted to a 10-bit coded signal by the 8b / 10b encoder 13. Further, the 10-bit coded signal as the data signal and the 8-bit coded signal as the clock signal are converted into a pair of clock signals CL and a pair of data signals D by the serializer 14 and output to the transmission line L.

  In the source driver 202, the pair of clock signals CL and the pair of data signals D from the timing controller 109 are respectively converted into a 10-bit coded signal as a data signal and an 8-bit coded signal as a clock signal by the deserializer 21. Further, the 10-bit coded signal is converted into an 8-bit coded signal by the 8b / 10b decoder 22. Further, the 8-bit coded signal as the clock signal and the 8-bit coded signal as the data signal are converted into a drive signal Ds for driving the data line of the liquid crystal panel by the command decoder 24 and output to the liquid crystal panel 204. .

  Further, Patent Document 1 discloses a method called LVDS (Low Voltage Differential Signaling) as a signal transmission method. In this method, 7-bit data is multiplexed by parallel-serial conversion, and a pair of differences is obtained. A pair of differential signals for transmitting a parallel data clock is provided separately from the data as a moving signal, and the signal is transmitted.

  Also, in this Patent Document 1, a plurality of bits of parallel data to be transmitted is converted into serial data, and a word clock indicating a data delimiter in the serial data is added as one bit of information. There has been proposed a method of generating a multi-valued logic signal to be transmitted and transmitting it through a single transmission line.

  By the way, in recent electronic devices that use a lot of digital circuits, when signals are transmitted, they are radiated into the air as unnecessary electromagnetic waves through patterns and cables on the circuit board, and these electromagnetic waves affect other electronic devices and themselves There is.

  In particular, the level of electromagnetic interference (EMI, Electro Magnetic Interference) has been increased with the increase in circuit scale due to high definition of liquid crystal display devices and the increase in the size of antenna parts accompanying the increase in size.

JP 2005-142872 A

  However, the above-mentioned LVDS method and the technique of Patent Document 1 are intended to improve the efficiency of signal transmission including the cost, and have not been considered for the reduction of EMI. In particular, when transmitting an image signal of a specific display pattern such as a signal for full-color display on a liquid crystal television, EMI noise may increase depending on the display pattern.

  The present invention has been made in view of the above problems, and is to obtain a liquid crystal display device capable of reliably reducing EMI and an electronic information device equipped with such a liquid crystal display device. Objective.

  A liquid crystal display device according to the present invention includes a liquid crystal panel that displays an image, a source driver that drives a data line of the liquid crystal panel, a scanning driver that drives a scanning line of the liquid crystal panel by a scanning signal, the source driver, A liquid crystal display device for displaying an image based on a video signal, wherein the timing controller randomly transmits a data signal to be supplied to the source driver at a constant cycle. The source driver has a demodulating unit that demodulates the modulated data signal from the timing controller, thereby achieving the above object.

  In the liquid crystal display device according to the aspect of the invention, the modulation unit modulates a data signal and a clock signal supplied to the source driver so that the phases thereof change randomly at a constant period, and the demodulation unit Preferably, it demodulates the modulated data signal and the modulated clock signal from the timing controller.

  According to the present invention, in the liquid crystal display device, the modulation unit has random number table information, and based on the random number table information, a phase of a data signal supplied to the source driver is randomly changed at a constant period. The demodulator has the same random number table information as the random number table information in the modulator, and demodulates the modulated data signal from the timing controller based on the random number table information It is preferable.

  In the liquid crystal display device according to the aspect of the invention, the modulation unit modulates a pulse signal as a data signal to be supplied to the source driver so that a rising timing thereof is randomly changed for each pulse. The unit preferably demodulates the pulse signal as the modulated data signal from the timing controller by adjusting the rising timing.

  According to the present invention, in the liquid crystal display device, the modulation unit modulates a pulse signal as a data signal to be supplied to the source driver based on the arrangement of 0 or 1 in the random number table information so that the rising timing is shifted. The demodulator demodulates the pulse signal as the modulated data signal from the timing controller by adjusting the rising timing based on the arrangement of 0 or 1 in the random number table information. It is preferable that

  In the liquid crystal display device according to the present invention, the liquid crystal display device includes a noise source that generates a noise signal, and the modulation unit randomly selects a data signal to be supplied to the source driver based on the noise signal at a constant period in phase. It is preferable that the demodulator demodulates the modulated data signal from the timing controller based on the noise signal.

  In the liquid crystal display device according to the aspect of the invention, the modulation unit includes a modulation-side sawtooth wave generation unit that generates a sawtooth wave, and a modulation-side comparison unit that compares the sawtooth wave and the noise signal. The data signal to be supplied to the source driver is modulated based on the comparison output of the unit so that the phase thereof changes randomly at a constant period, and the demodulation unit is generated by the sawtooth wave generation unit of the modulation unit A demodulating sawtooth wave generating unit that generates the same sawtooth wave as the sawtooth wave, and a demodulating side comparing unit that compares the sawtooth wave and the noise signal, based on the comparison result in the demodulating side comparing unit It is preferable to demodulate the modulated data signal from the timing controller.

  According to the present invention, in the liquid crystal display device, the timing controller includes a command encoder that converts the video signal into an 8-bit coded signal, a modulation unit that modulates the 8-bit coded signal, and a modulated 8-bit code. 8b / 10b encoder that converts a coded signal into a 10-bit coded signal, and a serializer that converts the 10-bit coded signal into a serial signal and outputs a pair of serial data signals and a pair of clock signals CL to a transmission line It is preferable to have.

  According to the present invention, in the liquid crystal display device, the source driver receives a pair of serial data signals and a pair of clock signals output from the serializer via a transmission line, and these signals are 10-bit coded signals. A deserializer for converting into a parallel signal, an 8b / 10b decoder for converting the 10-bit coded signal into an 8-bit coded signal, a demodulator for demodulating the 8-bit coded signal, and a demodulated 8-bit code It is preferable to have a command decoder that converts the conversion signal into a driving signal for the liquid crystal panel and applies the converted signal to the data of the liquid crystal panel.

  In the liquid crystal display device according to the aspect of the invention, the timing controller includes a modulation unit that modulates a scan signal supplied to the scan driver so that a phase thereof is randomly changed at a constant period. It is preferable to have a demodulator that demodulates the modulated scanning signal from the timing controller.

  The electronic information device according to the present invention is an electronic information device having a display unit, and the display unit includes the above-described liquid crystal display device according to the present invention, thereby achieving the above object.

  Next, the operation of the present invention will be described.

  In the present invention, it is possible to suppress the occurrence of protruding frequency peaks in the transmission signal. In other words, since the rising timing of the pulse signal as a video signal is sequentially modulated and transmitted from the timing controller to the source driver using a method that has neither regularity nor reproducibility, modulation without periodicity can be performed. It becomes possible to disperse the protruding frequency peaks. As a result, the peak of the transmission signal becomes small and no prominent peak that is a main spectrum component of EMI appears, so that EMI can be effectively reduced.

  As described above, according to the present invention, in the liquid crystal display device, it is possible to reduce EMI by suppressing the frequency peak of the transmission signal transmitted from the timing controller to the source driver.

FIG. 1 is a diagram illustrating a liquid crystal display device according to Embodiment 1 of the present invention. FIG. 2 is a block diagram showing a specific configuration of the timing controller and the source driver in the liquid crystal display device according to Embodiment 1 of the present invention. FIG. 3 is a diagram for explaining the operation of the liquid crystal display device according to the first embodiment of the present invention. The timing of the modulated video signal (FIG. (B)) is changed to the timing of the unmodulated video signal (FIG. (A)). It is shown in comparison with)). FIG. 4 is a diagram illustrating the operation of the liquid crystal display device according to the first embodiment of the present invention, and is a diagram illustrating a process for modulating a video signal. FIG. 5 is a diagram illustrating a liquid crystal display device according to Embodiment 2 of the present invention. FIG. 6 is a block diagram showing a specific configuration of the timing controller and the source driver in the liquid crystal display device according to Embodiment 2 of the present invention. FIG. 7 is a block diagram showing the modulation unit of the timing controller and the demodulation unit of the source driver in the liquid crystal display device according to Embodiment 2 of the present invention. FIG. 8 is a diagram for explaining the operation of the liquid crystal display device according to the second embodiment of the present invention, and is a diagram for explaining processing for modulating a video signal. FIG. 9 is a diagram for explaining a conventional liquid crystal display device. FIG. 10 is a block diagram showing a specific configuration of the timing controller 201 and the source driver 202 in the conventional liquid crystal display device.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 is a diagram illustrating a liquid crystal display device according to Embodiment 1 of the present invention.

  In this liquid crystal display device 100, instead of the timing controller 201 and the source driver 202 in the conventional liquid crystal display device 200, timing at which EMI noise caused by a pulse signal as a video signal transmitted from the timing controller to the source driver can be reduced. A controller 101 and a source driver 102 are provided, and other configurations are the same as those of the conventional liquid crystal display device 200.

  That is, the liquid crystal display device 100 receives the video signal Vs output from the image engine, outputs a timing signal (clock signal) CL and a modulated data signal Dr, and a timing controller 101 that outputs a scanning signal Cs. A liquid crystal panel 204 for displaying an image, a source driver 102 for driving a signal line of the liquid crystal panel based on the timing signal CL and the modulated data signal D, and a scanning line for the liquid crystal panel 204 based on the scanning signal Cs. And a scanning driver 203 to be driven.

  FIG. 2 shows a specific configuration of the timing controller 101 and the source driver 102 in the liquid crystal display device 100 of the first embodiment.

  The timing controller 101 includes a command encoder 11 that separates a data signal and a clock signal included in the digital video signal Vs and converts them into 8-bit coded signals, and a modulation unit that modulates the 8-bit coded signals as the data signals. 12, an 8b / 10b encoder 13 for converting the modulated 8-bit coded signal into a 10-bit coded signal, and converting the 10-bit coded signal and the 8-bit coded signal as a clock signal into a serial signal The serializer 14 outputs a pair of serial data signals D and a pair of clock signals CL to the transmission line L.

  The source driver 102 receives a pair of serial data signals D and a pair of clock signals CL output from the serializer 14 via a transmission line L, and these signals are a 10-bit coded signal and a clock signal as data signals. A deserializer 21 for converting the data signal into an 8-bit coded signal, an 8b / 10b decoder 22 for converting a 10-bit coded signal as a data signal into an 8-bit coded signal, and an 8-bit coded signal as a data signal The demodulating unit 23 that demodulates, the demodulated 8-bit coded signal, and the 8-bit coded signal as the clock signal from the deserializer 21 are converted into the drive signal Ds of the liquid crystal panel 204 and applied to the data of the liquid crystal panel. And a command decoder 24.

  Here, the command encoder 11, the 8b / 10b encoder 13 and the serializer 14 constituting the timing controller 101 are the same as those in the conventional liquid crystal display device 200, and the deserializers 21, 8b / The 10b decoder 23 and the command decoder 24 are the same as those in the conventional liquid crystal display device 200.

  Further, the signal transmission path between the timing controller 101 and the source driver 102 is constituted by wiring of a printed circuit board and various cables.

  In the first embodiment, the modulation unit 12 included in the timing controller 101 randomly sets the pulse rising timing for each pulse cycle, for example, for the pulse signal as the data signal output from the command encoder 11. A modulation process for shifting is performed.

  3A shows the rise timing of a pulse signal as an unmodulated data signal (input of the modulation unit), and FIG. 3B shows a pulse as a modulated data signal (output of the modulation unit). The rising timing of the signal is shown.

  Here, when a pulse signal Pv as an unmodulated data signal (input of the modulation unit) and a pulse signal MPv as a modulated data signal (output of the modulation unit) are compared, an unmodulated data signal is obtained. In the pulse signal Pv, the rise of the pulse occurs at a constant period, whereas in the pulse signal MPv as the modulated data signal, the rise of the pulse is randomly shifted.

  FIG. 4 is a diagram for explaining a process of randomly shifting the pulse rising timing in the modulation unit 12, showing random number information (FIG. (A)) and a method using the random number information (FIG. (B)). Yes.

  For example, the modulation unit 12 includes a storage unit (not shown) that stores random number information R (FIG. 4A) including a random arrangement of 0 and 1, and a serial connection that delays an input pulse signal. A plurality of delay elements and a plurality of switch elements connected in parallel with each of the delay elements, and each time a pulse signal is input, the switch elements are arranged in accordance with an array of four consecutive 0s and 1s. The delay amount is adjusted by switching on and off.

  Specifically, for example, for the first pulse, the random number array R1 is used, and the first value “0” Sd of the random number array R1 indicates in which direction the rising edge of the pulse is shifted from the second. The fourth value “100” indicates the amount by which the rising edge of the pulse is shifted.

  In accordance with such a rule, the rising timing of the second and subsequent pulses following the first pulse is shifted according to the random number array R2 to Rn, respectively, thereby modulating the input pulse signal Pv with the rising timing randomly shifted. A signal MPv is obtained.

  Similarly to the modulation unit 12, the demodulation unit 23 is input with a storage unit (not shown) that stores random number information R (FIG. 4A) including a random arrangement of 0 and 1. It has a plurality of delay elements connected in series for delaying a pulse signal and a plurality of switch elements connected in parallel with each of these delay elements, and each time a pulse signal is input, four consecutive 0s According to the arrangement of 1 and 1, the switching element is switched on and off to adjust the delay amount. However, in this demodulator 23, the switch element is switched on and off so that the rising timing shifted by the modulator 12 returns to the timing before shifting.

  Next, the operation will be described.

  In the liquid crystal display device 100 of the first embodiment having such a configuration, when the digital video signal Vs output from the image engine is input, the timing controller 101 performs the data signal D and the clock signal CL based on this signal. Are output to the source driver 102 and the scanning signal Cs is output to the scanning driver 203.

  When the data signal D and the clock signal CL are input to the source driver 102 and the scanning signal Cs is input to the scanning driver 203, the source driver 102 outputs a data line driving signal to the data line of the liquid crystal panel 204, and scans. The driver 203 outputs a scanning line driving signal to the scanning line of the liquid crystal panel 204. As a result, the liquid crystal panel 204 displays an image corresponding to the input video signal Vs.

  Such an operation is the same as that in the conventional liquid crystal display device 200.

  In the timing controller 101 of the liquid crystal display device 100 according to the first embodiment, after the data signal and the clock signal included in the video signal Vs input by the command encoder 11 are separated and converted into an 8-bit coded signal, The 8-bit coded signal as the data signal is modulated by the modulation unit 12. As a result, the 8-bit coded signal as the pulse signal rises at a position that is randomly shifted with respect to the reference rise timing whose rise timing coincides with the pulse period.

  The 8-bit coded signal thus modulated is converted into a 10-bit coded signal by the 8b / 10b encoder 13. Further, the 10-bit coded signal and the 8-bit coded signal as the clock signal from the command encoder 11 are converted into a pair of clock signals CL and a pair of data signals D by the serializer 14 and output to the transmission line L. .

  In the source driver 102, the pair of clock signals CL and the pair of data signals D from the timing controller 101 are converted by the deserializer 21 into a 10-bit coded signal as a data signal and an 8-bit coded signal as a clock signal. The 10-bit coded signal is converted into an 8-bit coded signal by the 8b / 10b decoder 22, and then the 8-bit coded signal as the data signal is demodulated by the demodulator 23.

  Then, the demodulated 8-bit coded signal and the 8-bit coded signal as the clock signal from the deserializer 21 are converted by the command decoder 24 into a drive signal Ds for driving the data line of the liquid crystal panel, and are supplied to the liquid crystal panel 204. Is output.

  In the liquid crystal display device 100 according to the first embodiment having such a configuration, the rising timing of the pulse signal is randomly shifted by the modulation unit in the timing controller by modulating the data signal (pulse signal) transmitted as the video signal. Therefore, it is possible to avoid the appearance of a peak of a prominent frequency that is a main spectrum component of EMI, and thus it is possible to effectively reduce EMI.

That is, in this embodiment, a modulation unit is installed in the timing controller on the transmission side, and a demodulation unit is installed in the source driver on the signal reception side, and the pulses of the data signals transmitted between them are randomly modulated. Therefore, it is possible to suppress the occurrence of protruding frequency peaks in the transmitted data signal. In addition, because the method does not have regularity or reproducibility, the rise timing of the pulse signal as a data signal is modulated in sequence and transmitted from the timing controller to the source driver, so modulation without periodicity can be performed. It becomes possible to disperse the protruding frequency peaks. As a result, the peak of the data signal to be transmitted is reduced and no prominent peak that is the main spectrum component of EMI appears, so that EMI can be effectively reduced. Since the 8-bit coded signal is converted into a 10-bit coded signal by the 8b / 10b encoder 13, the “0” or “1” level in the pulse signal as the data signal serially output from the serializer is unevenly distributed. It is possible to suppress the waveform rounding of the pulse signal.

(Embodiment 2)
FIG. 5 is a diagram illustrating a liquid crystal display device according to Embodiment 2 of the present invention.

  The liquid crystal display device 100 a is replaced with a noise source 110 and a noise signal Ns generated from the noise source 110 instead of the timing controller 101 and the source driver 102 in the liquid crystal display device 100 of the first embodiment. A timing controller 101a and a source driver 102a that can reduce EMI noise due to a pulse signal as a data signal transmitted to the source driver are provided. Since other configurations of the second embodiment are the same as those of the liquid crystal display device 100 of the first embodiment, the timing controller 101a and the source driver 102a in the liquid crystal display device 100a of the second embodiment will be described below.

  FIG. 6 shows a specific configuration of the timing controller 101a and the source driver 102a in the liquid crystal display device 100 of the second embodiment.

  The timing controller 101a includes a modulation unit 12a that modulates the 8-bit coded signal from the command encoder 11 based on the noise signal Ns from the noise source 110, instead of the modulation unit 12 in the timing controller 101 of the first embodiment. The other configurations are the same as those in the timing controller 101 of the first embodiment.

  The source driver 102a demodulates the 8-bit coded signal from the 8b / 10b decoder 22 based on the noise signal Ns from the noise source 110 instead of the modulation unit 12 in the source driver 102 of the first embodiment. The demodulator 23 is provided, and other configurations are the same as those in the source driver 102 of the second embodiment.

  In the second embodiment, the modulation unit 12a configuring the timing controller 101a randomly sets the rising timing of the pulse for each cycle of the pulse, for example, as the data signal output from the command encoder 11. A modulation process for shifting is performed.

  Hereinafter, the modulation unit 12a and the demodulation unit 23a of the second embodiment will be described.

  FIG. 7 is a diagram for explaining the modulation unit 12a and the demodulation unit 23a, and shows the configuration of the modulation unit 12a and the demodulation unit 23a (FIGS. (A) and (b)).

  FIG. 8 is a diagram for explaining a process of randomly shifting the rising timing of the pulse signal in the modulation unit 12a, and shows a ramp waveform (FIG. (A)) and a pulse waveform (FIG. (B)) used for modulation. .

  Here, the modulation unit 12a includes a sawtooth wave generation unit 121 that generates a sawtooth wave RAMP, a voltage comparison unit 122 that compares the sawtooth wave RAMP and a noise signal Ns from the noise source 110, and based on the comparison result. Based on the pulse width of the adjustment pulse Pr from the delay amount generator 123 and the delay amount generator 123 that generates the adjustment pulse Pr whose pulse width is a period in which the amplitude of the sawtooth wave RAMP is larger than the amplitude of the noise signal Ns. And a pulse phase change circuit 124 that outputs the modulated pulse signal MPb by shifting the rising timing of the pulse signal Pv as the data signal from the command encoder 11.

  Further, the demodulator 23a compares the sawtooth wave generator 231 that generates the same sawtooth wave as the sawtooth wave RAMP generated by the sawtooth wave generator 121 with the sawtooth wave RAMP and the noise signal Ns from the noise source 110. Based on the comparison result, the voltage comparison unit 232, a delay amount generation unit 233 that generates an adjustment pulse Pr having a period in which the amplitude of the sawtooth wave RAMP is larger than the amplitude of the noise signal Ns, and the delay amount generation unit A pulse phase demodulating circuit 234 that outputs the demodulated pulse signal RPv by shifting the rising timing of the modulated pulse signal MPv as the data signal from the 8b / 10b decoder 22 based on the pulse width of the adjustment pulse Pr from 233; have.

  Also in the liquid crystal display device 100a of the second embodiment having such a configuration, similarly to the liquid crystal display device 100 of the first embodiment, a data signal (pulse signal) transmitted as a video signal is transmitted by the modulation unit 12a in the timing controller. Due to the modulation, the rise timing of the pulse signal is randomly shifted, so that it is possible to avoid the emergence of a prominent frequency peak, which is the main spectrum component of EMI, and it is possible to effectively reduce EMI. It becomes.

  In the first and second embodiments, the example in which the rising timing of the pulse signal as the data signal supplied from the timing controller to the source driver is modulated. However, the pulse signal as the clock signal supplied from the timing controller to the source driver is shown. The rising timing of the pulse signal may be modulated, and the data signal and the clock signal included in the video signal transmitted from the timing controller to the source driver may be modulated with respect to the rising timing of the pulse signal. .

  For example, when modulating the rising timing of a pulse signal as a clock signal supplied from the timing controller to the source driver, in the first and second embodiments, instead of the data signal output from the command encoder, the clock signal is The clock signal may be supplied to the command decoder 24 via the 8b / 10b decoder and modulation unit instead of the data signal output from the deserializer.

  When both the data signal and the clock signal supplied from the timing controller to the source driver are modulated with the rising timing of the pulse signal, the data signal and the clock signal output from the command encoder in the first and second embodiments. Are supplied to the serializer via the modulator and the 8b / 10b encoder, and the data signal and the clock signal output from the deserializer are both supplied to the command decoder 24 via the 8b / 10b decoder and the modulator. .

  Further, the timing controller has a modulation unit similar to the above embodiment that modulates the rising timing of the pulse signal as the scanning signal supplied to the scanning driver, and the scanning driver outputs the pulse signal as the modulated scanning signal. You may have the demodulation part similar to the said embodiment to demodulate.

  That is, according to the present invention, in a liquid crystal display device, at least one of a pulse signal as a data signal, a pulse signal as a clock signal, and a pulse signal as a scanning signal has its pulse rising timing shifted at random. By modulating, the effect of reducing EMI can be obtained.

  Although not particularly mentioned in the description of the first and second embodiments, the liquid crystal display device of the above-described embodiment is an image display of a mobile device such as a mobile phone or an electronic information device such as a stationary liquid crystal television. It can be used as a part.

  As mentioned above, although this invention has been illustrated using preferable embodiment of this invention, this invention should not be limited and limited to this embodiment. It is understood that the scope of the present invention should be construed only by the claims. It is understood that those skilled in the art can implement an equivalent range based on the description of the present invention and the common general technical knowledge from the description of specific preferred embodiments of the present invention. Patents, patent applications, and documents cited herein should be incorporated by reference in their entirety, as if the contents themselves were specifically described herein. Understood.

  In the field of liquid crystal display devices, the present invention makes it possible to reduce EMI by suppressing the frequency peak of a transmission signal transmitted from a timing controller to a source driver, and to reliably reduce EMI. A display device can be provided.

11 Command encoder 12, 12a Modulator 13, 22 8b / 10b encoder,
14 Serializer,
21 Deserializer,
23, 23a Demodulator 24 Command decoder,
DESCRIPTION OF SYMBOLS 100, 100a Liquid crystal display device 101, 101a Timing controller 102, 102a Source driver 121, 131 Sawtooth wave generation part 122, 232 Voltage comparison part 123, 233 Delay amount generation part 124 Pulse phase change circuit 110 Noise source 203 Scan driver 204 Liquid crystal panel 234 Pulse phase recovery circuit L Transmission path

Claims (10)

A liquid crystal panel for displaying an image; a source driver for driving data lines of the liquid crystal panel; a scanning driver for driving scanning lines of the liquid crystal panel by a scanning signal; a timing controller for controlling the source driver and the scanning driver; A liquid crystal display device for displaying an image based on a video signal,
The timing controller includes a modulation unit that modulates a data signal to be supplied to the source driver so that the phase thereof randomly changes at a constant period,
The source driver have a demodulator for demodulating the modulated data signal from the timing controller,
The modulation unit modulates a data signal and a clock signal supplied to the source driver so that the phase thereof changes randomly at a constant period,
The liquid crystal display device , wherein the demodulator demodulates a modulated data signal and a modulated clock signal from the timing controller . The liquid crystal display device according to claim 1.
The modulation unit has random number table information, and based on the random number table information, modulates a data signal to be supplied to the source driver so that the phase thereof randomly changes at a constant period,
The demodulator has a random number table information identical to the random number table information in the modulator, and demodulates a modulated data signal from the timing controller based on the random number table information . The liquid crystal display device according to claim 2 ,
The modulation unit modulates a pulse signal as a data signal to be supplied to the source driver so that the rising timing thereof changes randomly for each pulse,
The liquid crystal display device, wherein the demodulating unit demodulates a pulse signal as a modulated data signal from the timing controller by adjusting a rising timing. The liquid crystal display device according to claim 3 .
The modulation unit modulates a pulse signal as a data signal to be supplied to the source driver based on an array of 0 or 1 in the random number table information so that rising timing thereof is shifted,
The demodulator demodulates a pulse signal as a modulated data signal from the timing controller based on an array of 0 or 1 in the random number table information by adjusting its rising timing. apparatus. The liquid crystal display device according to claim 1.
Having a noise source to generate a noise signal;
The modulation unit modulates a data signal to be supplied to the source driver based on the noise signal so that the phase thereof changes randomly at a constant period.
The liquid crystal display device, wherein the demodulating unit demodulates a modulated data signal from the timing controller based on the noise signal. The liquid crystal display device according to claim 5 .
The modulator is
A modulation-side sawtooth wave generator for generating a sawtooth wave;
A modulation side comparator for comparing the sawtooth wave and the noise signal;
Based on the comparison output of the comparison unit, the data signal to be supplied to the source driver is modulated so that the phase thereof randomly changes at a constant period,
The demodulator
A demodulation-side sawtooth wave generator that generates the same sawtooth wave as the sawtooth wave generated by the sawtooth wave generator of the modulator;
A demodulation side comparison unit for comparing the sawtooth wave and the noise signal;
A liquid crystal display device that demodulates a modulated data signal from the timing controller based on a comparison result in the demodulation side comparison unit. The liquid crystal display device according to claim 1.
The timing controller is
A command encoder for converting the video signal into an 8-bit coded signal;
The modulation unit is configured to modulate the 8-bit coded signal as a data signal to be supplied to the source driver ,
The timing controller is
An 8b / 10b encoder that converts the modulated 8-bit coded signal into a 10-bit coded signal;
A liquid crystal display device having a serializer that converts the 10-bit coded signal into a serial signal and outputs a pair of serial data signals and a pair of clock signals CL to a transmission line. The liquid crystal display device according to claim 7 .
The source driver receives a pair of serial data signals and a pair of clock signals output from the serializer via a transmission path, and converts these signals into parallel signals that are 10-bit coded signals; and
And a 8b / 10b decoder which converts the 10-bit coded signal into 8-bit coded signal,
The demodulator is configured to demodulate the 8-bit coded signal from the 8b / 10b decoder as a modulated data signal from the timing controller ,
The liquid crystal display device, wherein the source driver has a command decoder that converts a demodulated 8-bit coded signal into a driving signal for the liquid crystal panel and applies the converted signal to data of the liquid crystal panel. The liquid crystal display device according to claim 1.
The timing controller has a modulation unit that modulates a scanning signal supplied to the scanning driver so that the phase thereof changes randomly at a constant period,
The liquid crystal display device, wherein the scan driver includes a demodulator that demodulates a modulated scan signal from the timing controller. In an electronic information device having a display unit,
The display unit is an electronic information device having the liquid crystal display device according to claim 1.

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