JP2007171609A - Display device and driving method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display device and a driving method therefor, in which the noises generated by interference between the driving frequency of an inverter used for back-light of the display device and a driving signal frequency of display elements are reduced, and the display device can be used in several driving timings. <P>SOLUTION: Input signals of driving timings a, b, c of users A, B, C are converted into a specific driving signal of a driving timing d, and the display elements are always driven by the signal of the converted specific driving timing d, and the driving frequency of the inverter of a light source unit is adjusted to the frequency Fd which does not interfere with the signal of the specific driving timing d. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a display device such as a liquid crystal display module and a method for driving the display device, and in particular, it is possible to reduce interference noise due to an inverter used in a backlight, and to drive a display device and a display device with excellent display image quality. It is about the method.

  As a display device used for a computer monitor, a television, an information terminal or the like, there is a liquid crystal display module, for example. The liquid crystal display module includes a liquid crystal panel provided as a display element, in which a liquid crystal layer is provided between two substrates provided with a transparent electrode, and the light transmittance of the liquid crystal layer changes when a voltage is applied to the transparent electrode. . The liquid crystal display module requires a light source from the outside because the liquid crystal panel itself does not emit light. A light source outside the liquid crystal display module that uses natural light, room light, or other external light (reflective type) or a light source unit such as a backlight is placed behind the liquid crystal panel to illuminate from behind the liquid crystal panel. There is a method (transmission type).

  The backlight of a liquid crystal display module is usually formed by using a cold cathode fluorescent tube as a light source lamp, converting light from the cold cathode fluorescent tube into a surface light source, and irradiating the entire liquid crystal panel with light. . The backlight also includes an inverter for driving the cold cathode fluorescent tube. The backlight converts various DC voltages such as 12V, 24V, 17.5V, and 350V into an AC voltage of several hundreds to thousands of volts by an inverter, and turns on the cold cathode fluorescent tube. Dimming by an inverter includes a digital method called an analog method and a pulse width modulation (hereinafter abbreviated as PWM) method. The PWM dimming system of the inverter adjusts the brightness by repeating the light emission and non-light emission of the cold cathode fluorescent tube at high speed and adjusting the ratio of the light emission time and the non-light emission time.

  When the backlight of the liquid crystal display module is driven by an inverter, noise enters the supply side of the power circuit board, the wiring board, etc., the panel wiring, and the like due to the drive frequency of the inverter, causing voltage fluctuations. If the period of voltage fluctuation of the liquid crystal display module interferes with various driving frequencies such as horizontal sync signal, vertical sync signal, or clock frequency, horizontal waves called waving noise and flickering occur on the liquid crystal panel, and the display quality is improved. Reduce.

  In addition, when the cold cathode fluorescent tube is dimmed by a PWM dimming inverter, the PWM signal dimming signal repeats light emission and non-light emission in a short cycle, so depending on the dimming frequency of the PWM signal of the inverter, the liquid crystal Interference occurs between various driving frequencies for driving the display module, and waving noise or the like is generated on the liquid crystal panel, thereby degrading the display quality. That is, in the case of the PWM dimming type inverter, the frequency of the voltage fluctuation due to the driving of the inverter interferes with various driving frequencies to reduce display quality, and the frequency of the PWM dimming signal interferes with various driving frequencies. However, there is a problem that the display quality is lowered.

  In order to prevent such deterioration of display quality due to the inverter, a method of synchronizing the PWM dimming signal of the inverter and the vertical synchronization signal of the liquid crystal panel (for example, refer to Patent Document 1), a predetermined number of cathode ray fluorescent tubes A method of driving a cathode ray fluorescent tube with an inverter driving frequency that has a time difference or a phase difference and that is an integer multiple of the frequency of the vertical synchronization signal is known (for example, see Patent Document 2).

JP 2003-75804 A (0032) JP 2003-287734 A (0013)

  By the way, the liquid crystal display module is used as a display device for various uses such as a computer monitor, an information equipment terminal, and a television. The clock frequency, which is the driving timing of the liquid crystal display module, varies depending on the usage application of the liquid crystal display device. If the liquid crystal display module is formed so as to be compatible with various drive timings of signals input from the outside, the single liquid crystal display module can be used for a wide range of users and various uses.

  Conventionally, even when the liquid crystal panel (display element) is driven at various drive timings, the drive frequency of the inverter is adjusted so as to be synchronized with only one drive timing of the display element. FIG. 1 is an explanatory diagram of a conventional driving method of a display device. For example, as shown in FIG. 1, the input signal 101a of the user (user) A is the drive timing a, the input signal 101b of the user B is the drive timing b, and the input signal 101c of the user C is the drive timing c. The driving timings of the input signals are different from each other. In this case, the conventional display device is formed such that the drive 102a to 102c of the display element is driven by signals at drive timings a to c. The drive frequency Fa of the inverter 104 used for the backlight of the display device is adjusted to a frequency that does not interfere with the signal of the drive timing a that drives the display element.

  As shown in FIG. 1, when the user A drives the display element with the signal at the drive timing a, no noise is generated (103). However, when the user B drives the display element with the signal at the drive timing b, or when the user C drives the display element with the signal at the drive timing c, the drive frequency Fa of the inverter interferes with the frequencies of the drive timings b and c. Therefore, there is a problem that noise is generated due to interference between the drive frequency of the inverter and the drive signal of the display element (105).

  Conventionally, as a countermeasure against the above problem, the inverter driving frequency is adjusted to driving frequencies Fb and Fc adjusted so as not to interfere with the signals of the driving timing b and driving timing c of the display element, respectively. There was no choice but to compose the light. In the case of the PWM dimming type inverter, the problem of interference also occurs between the dimming frequency and the drive timing of the display element.

  However, if the drive frequency or dimming frequency of the inverter is adjusted to a specific drive timing of the display element (hereinafter, the drive frequency or dimming frequency of the inverter may be simply referred to as the inverter frequency), the drive timing of the display element Is limited to one, the display device cannot be driven by a plurality of driving timing signals. As a result, as many display devices as the required drive timing are required.

  Also, when adjusting the inverter frequency, the frequency of the inverter and the drive timing of the liquid crystal panel are synchronized, so the inverter frequency is changed while actually viewing the display, and it is difficult to interfere with the drive timing of the liquid crystal panel It was necessary to find and adjust fine frequencies. However, finding the optimum inverter frequency according to the driving timing of the liquid crystal panel is a very time-consuming work.

  The problem to be solved by the present invention is to reduce noise caused by interference between the frequency of the inverter used for the backlight of the display device and the frequency of the drive signal of the display element, and to enable the display device to be used at a plurality of drive timings. It is an object of the present invention to provide a display device and a method for driving the display device that can be widely used in various applications with a single display device.

  In order to solve such problems, the display device of the present invention includes a display element for displaying an image by modulating light from a light source based on a signal input from the outside, and various types of input from the outside. And a signal converting means for converting the drive timing signal into a specific drive timing signal, and a drive means for driving the display element based on the specific drive timing signal. is there.

  The display device of the present invention preferably includes a light source unit that includes a lamp and an inverter that drives the lamp to irradiate the display element with light.

  The display device of the present invention includes a light source unit that includes a lamp and an inverter that drives the lamp, and irradiates the display element with light, and the drive frequency of the inverter interferes with a signal of a specific drive timing that drives the display element. It is preferable that it is formed so that it does not.

  The display device according to the present invention includes a light source unit that includes a lamp and an inverter that drives the lamp, and irradiates the display element with light. A light control frequency of the inverter and a signal of a specific drive timing for driving the display element are provided. It is preferably formed so as not to interfere.

  The display device according to the present invention includes a light source unit for irradiating light to a display element, which includes a lamp and a PWM dimming inverter that drives the lamp, and includes a drive frequency and / or dimming frequency of the inverter and the display element. It is preferable that a signal at a specific driving timing for driving the device is not interfered.

  In the display device of the present invention, it is preferable that the signal conversion means includes an internal clock for generating a specific drive timing.

  In the display device of the present invention, it is preferable that the signal conversion means includes a memory for storing a signal input from the outside for a certain period of time.

  In the display device of the present invention, it is preferable that the signal for the specific drive timing is any one of a horizontal synchronization signal, a vertical synchronization signal, and a clock signal.

  According to the display device driving method of the present invention, signals of various drive timings inputted from the outside are converted into signals of specific drive timings, and the display elements are driven based on the signals of the specific drive timings. The gist is to modulate the irradiated light and display an image on the display element.

  In the display device driving method of the present invention, the lamp of the light source is preferably driven by an inverter.

  In the display device driving method of the present invention, it is preferable that when the lamp of the light source is driven by an inverter, the drive frequency of the inverter and a signal of a specific drive timing for driving the display element do not interfere with each other.

  In the display device driving method of the present invention, it is preferable that when the lamp of the light source is dimmed by the inverter, the dimming frequency of the inverter does not interfere with a signal of a specific driving timing for driving the display element.

  In the driving method of the display device of the present invention, when the lamp of the light source is driven by the PWM dimming inverter, the inverter driving frequency and / or the dimming frequency interferes with a signal of a specific driving timing for driving the display element. It is preferable not to do so.

  In the driving method of the display device of the present invention, it is preferable to convert various drive timing signals input from the outside into signals of specific drive timings using an internal clock.

  In the driving method of the display device of the present invention, it is preferable that signals of various driving timings input from the outside are input to the memory, stored for a certain period of time, and then output to be converted into specific driving timings.

  In the driving method of the display device of the present invention, it is preferable that the signal for the specific driving timing is any one of a horizontal synchronizing signal, a vertical synchronizing signal, and a clock signal.

  In the present invention, the frequency of the inverter (drive frequency and dimming frequency) and the specific drive timing signal of the display element are formed so as not to interfere with each other, interference fringes resulting from interference on the screen of the display element, This means that waving noise and noise such as flicker are not generated. Specifically, in order to avoid interference so that the inverter frequency and the drive timing signal of the display element do not interfere with each other, either the frequency of the inverter or the drive timing signal of the display element is changed so that the noise is not generated. Just do it.

  According to the display device of the present invention, signal conversion means for converting signals of various drive timings input from the outside into signals of specific drive timings and the display elements are driven based on the signals of specific drive timings. Since the display element is always driven at a specific drive timing even if the input signal is a signal having various drive timings, it can be specified regardless of the drive timing of the input signal. The display quality of the display element is reduced by the inverter by forming so that only the drive timing signal and the drive frequency and dimming frequency of the inverter such as the backlight used for the light source of the display element do not interfere with each other. Can be easily prevented.

  That is, the drive device according to the present invention can prevent interference fringes on the display element or interference fringes on the screen of the display element due to interference between the frequency of voltage fluctuation and the drive frequency of the display element even if voltage fluctuation occurs due to driving of the inverter. The occurrence of waving noise that moves up and down, flickering of the screen, and the like can be prevented, and the display quality of the display element can be prevented from deteriorating.

  Furthermore, since the display device of the present invention can be driven by a plurality of drive timing signals, the single display device can be widely used for various applications.

  According to the driving method of the display device of the present invention, signals of various driving timings inputted from the outside are converted into signals of a specific driving timing, and the display element is driven based on the signals of the specific driving timing. Because it modulates the light emitted from the light source and displays an image on the display element, the display element is always driven at a specific drive timing even if the input signal is a signal having various drive timings. Therefore, it is possible to prevent interference between only a signal at a specific drive timing regardless of the drive timing of the input signal and a frequency such as a drive frequency or a dimming frequency of an inverter such as a backlight used for a light source of a display element. By forming them, it is possible to easily prevent the display quality of the display element from being lowered by the inverter.

  That is, according to the driving method of the present invention, even if voltage fluctuation occurs due to driving of the inverter, interference fringes on the display element due to interference between the frequency of voltage fluctuation and the driving frequency of the display element, Generation of waving noise that moves up and down on the screen, flickering of the screen, and the like can be prevented, and deterioration in display quality of the display element can be prevented.

  Further, since the display device can be driven by a plurality of drive timing signals by using the display device driving method of the present invention, one display device can be widely used for various applications.

  FIG. 2 is an explanatory diagram showing a driving method of the display device of the present invention. A method for driving the display device of the present invention will be described. For example, as in the case of FIG. 1, when the input signals 201a, 201b, and 201c of the users A, B, and C are input with the signals of the drive timings a, b, and c, these various drive timings a to The signal c is converted into a signal having a specific drive timing d called the drive timing d by a signal conversion means or the like (202). The display element is driven by the converted signal at the drive timing d (203). That is, the display element is always driven by a signal having a specific drive timing called drive timing d, even if the drive timing of the input signal is different from a, b, and c.

  On the other hand, when a backlight comprising a cold cathode fluorescent tube and an inverter is used as a light source for irradiating light to the display element, for example, the drive frequency of the inverter 205 for driving the cold cathode fluorescent tube is a converted signal of the drive timing d of the display element. It is adjusted to the frequency Fd that does not interfere with. As a result, each of the users A, B, and C has different input signal drive timings, but the display element drive timing d and the drive frequency Fd of the inverter 205 do not interfere with each other, so that no noise is generated on the display element. (204) Deterioration of display quality can be prevented.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 3 is a block diagram illustrating a configuration of a liquid crystal display module including a transmissive liquid crystal panel as an example of the display device of the present invention. A liquid crystal display module 1 shown in FIG. 3 controls and drives the liquid crystal panel 4 as a display element for displaying an image by modulating light from a light source based on an externally input signal. The liquid crystal panel unit 2 includes a circuit, and the like. The backlight unit 3 includes a cold cathode fluorescent tube 31 and an inverter 32 as an external light source for irradiating the liquid crystal panel 4 with light.

  As a circuit for controlling and driving the liquid crystal panel 4 of the liquid crystal panel unit 2, a gate array 51 and a memory 52 for converting various drive timing signals input from the external system 6 into specific drive timing signals. And a signal converting means 5 comprising an internal clock 53 and the like, and a driving means comprising a driver such as a gate driver 7 and a source driver 8 for driving the liquid crystal panel 4 which is a display element based on a specific driving timing. ing.

As shown in FIG. 3, the liquid crystal panel 4 are provided at predetermined intervals perpendicular with the m source lines Y ₁ of · · · Y _m provided at predetermined intervals, and these source lines Y ₁ · · · Y _m M × n liquid crystal cells serving as pixels are arranged in a matrix at the intersection where _n gate lines X ₁ ... X _n intersect. A thin film transistor (TFT) as a switching element is provided for each pixel.

In the liquid crystal panel unit 2, source lines Y ₁ ... Y _m are connected to a source driver 8 for supplying data signals, and gate lines X _{1 to} X _n are connected to a gate driver 7 for supplying scanning signals. Has been. The liquid crystal panel unit 2 has a common AC drive circuit (not shown) connected to the liquid crystal panel 4 so that a common signal can be output to a common electrode provided on the color filter substrate side of the liquid crystal panel 4. Yes. The liquid crystal panel unit 2 is formed so that a gate signal voltage for driving the TFT, a source signal voltage for driving the liquid crystal, a common signal voltage, and the like are supplied from a power supply circuit (not shown).

  FIG. 4 is a cross-sectional view showing the schematic structure of the liquid crystal display panel 4 of FIG. 3 and the positional relationship of the backlight unit 3. The transmissive liquid crystal panel 4 constituting the liquid crystal display module 1 includes a color filter substrate 43 in which an alignment film, a common electrode, a color filter and the like 42 are provided on the surface of one transparent substrate 41, and a surface of the other transparent substrate 44. A liquid crystal cell 48 comprising an array substrate 46 provided with TFTs, display electrodes, alignment films 45 and the like, and a liquid crystal layer 47 sandwiched between the pair of transparent substrates 43, 46. It is comprised from a pair of polarizing plate 49a, 49b laminated | stacked on the front side and the back side. As shown in FIG. 4, the backlight unit 3 is provided on the back side of the liquid crystal panel 4.

  The backlight unit 3 includes a light source unit and a light control unit for uniformly irradiating light on the entire surface of the liquid crystal panel 4. In the liquid crystal display module of the mode shown in FIG. 3, the lamp of the light source unit of the backlight unit 3 is the cold cathode fluorescent tube 31, and the dimming unit is the inverter 32.

  Although not particularly shown, the light source portion of the backlight unit 3 is provided with a diffusion plate that diffuses light from the cold cathode fluorescent tube 31, a reflective plate that reflects light, and the like. The liquid crystal panel 4 can be irradiated as a uniform surface light source. As a specific structure of the light source unit of the backlight unit 3, an area light type or a direct type in which the cold cathode fluorescent tubes 31 are arranged behind the liquid crystal panel 4 or a side surface of a light guide plate disposed behind the liquid crystal panel 4 is used. There is an edge light system in which the cathode fluorescent tube 31 is installed.

  When the liquid crystal panel 4 drives each TFT provided for each pixel of the liquid crystal cell based on a signal input from the outside, the light transmittance of each pixel is controlled. In the liquid crystal panel 4, the brightness of the display screen of the light emitted from the backlight unit 3 provided on the back side changes according to the light transmittance of each pixel. As a result, light from the light source is modulated based on an electrical signal input from the outside, and an image is displayed on the liquid crystal panel 4.

  FIG. 5 is a flowchart for explaining a method of driving the liquid crystal panel unit of FIG. Note that FIG. 5 shows the case of driving a VGA type liquid crystal panel. First, an input image signal is input from the external system 6 to the gate array 51 of the signal conversion means of the liquid crystal panel unit. In this case, as shown in FIG. 5, the specifications of the input image signal are clock (CK): 20 MHz to 30 MHz, horizontal period (Hsync): 790CK to 1620CK, and vertical period (Vsync): 517Hsync to 1000Hsync.

  Examples of the external system 6 include a television receiver and a computer information terminal, and examples of the input image signal input from the system 6 to the liquid crystal display module include a television signal, a video signal, and a monitor signal.

  The input image signal input from the system 6 to the gate array 51 includes a data signal, a synchronization signal, a clock signal, and the like. The synchronization signal is used as scanning synchronization information when an image is drawn on the liquid crystal panel. Examples of the synchronization signal include a horizontal synchronization signal and a vertical synchronization signal. The input image signal is driven at a predetermined drive timing by a clock signal and a synchronization signal.

  The input image signal input to the signal conversion means 5 is converted into a specific drive timing from a predetermined drive timing of the input image signal by the gate array 51, the memory 52, the internal clock 53, and the like. An output image signal having timing is formed. In the apparatus shown in FIG. 3, the drive timing is converted by the following means.

  As shown in FIG. 5, when converting the drive timing of the image signal input to the gate array 51, first, the image signal of one line (Hsync) or one frame (Vsync) is input to the memory 52 and stored therein. The internal clock 53 creates a clock signal with a frequency of 30 MHz in the module. The gate array 51 outputs the image signal stored in the memory 52 for a predetermined time based on the clock frequency created by the internal clock 53. The drive timing of the image signal output from the memory is converted and output as an output image signal having a specific drive timing. The specifications of the output image signal are clock (CK): 30 MHz, horizontal period (Hsync): 1620 CK, and vertical period (Vsync): 1000 Hsync.

  Since the signal conversion means 5 includes the memory 52, the drive timing can be easily converted. By inputting the input image signal into the memory 52, storing it for a certain time, and outputting it, the drive timing can be reliably converted. Further, by providing the signal conversion means 5 with the internal clock 53, the internal clock can be reliably generated. Then, by converting the signal using the internal clock, the input image signal can always be converted to a constant drive timing.

An output image signal having a specific drive timing is output from the signal conversion means 5 to a drive circuit including a gate driver 7 and a source driver 8. The gate driver 7 and the source driver 8 is an LSI for driving the liquid crystal panel 4 provided, the gate driver 7 be connected to the gate power supply, a line sequential gate pulse voltage to the gate lines X ₁ ··· X _n To do. The source driver 8 is connected to a gradation power source (not shown) and supplies a source signal for one line to the source lines Y ₁ ... Y _n . The gate pulse voltage is sequentially supplied to the gate lines X ₁ ... X _n to form one screen (one frame).

  The liquid crystal panel 4 always has the above drive timing [clock (CK): 30 MHz, horizontal synchronization (Hsync): 1620 CK, vertical synchronization (Vsync): 1000 Hsync] as long as it is within the specifications of the input image signal. It is driven by driving circuits such as a gate driver 7 and a source driver 8 based on the output image signal.

FIG. 6 is a diagram showing a PWM dimming transmission waveform of the inverter 32 used in the backlight unit. Hereinafter, driving of the backlight unit will be described. The backlight unit 3 supplies a drive signal (PWM signal) from the inverter 32 to the cold cathode fluorescent tube 31 to control on / off of the cold cathode fluorescent tube 31. As shown in FIG. 6, the inverter 32 supplies the cold cathode fluorescent tube 31 with a lighting pulse voltage having an oscillation period C _i to light the cold cathode fluorescent tube 31. Further PWM signal of the inverter, as shown in the figure, with the PWM dimming cycle _{C p} consisting of the light emission time _{T on} the non-emission time _{T off.} The cold cathode fluorescent tube 31 repeats light emission and non-light emission at high speed by the PWM signal of the inverter 32, and intermittently oscillates. The backlight unit may control the at dimming range to adjust the ratio of the light emission time T _on and the non-emission time T _off of the PWM signal. Thus, the PWM dimming method of the inverter is a digital dimming method, and the cold cathode fluorescent tube 31 can be dimmed in a wide dimming range.

The backlight unit 3 is adjusted so that the frequency of the inverter 32 is synchronized with a specific drive timing of the output image signal that drives the liquid crystal panel 4 and does not interfere with the output image signal that drives the liquid crystal panel. Has been. The frequency of the inverter 32 includes a drive frequency related to the drive cycle of the inverter and a dimming frequency related to the dimming cycle of the inverter. The oscillation cycle C _i shown in FIG. 6 is the drive cycle of the inverter, and the PWM dimming cycle C _p is the dimming cycle of the inverter. PWM dimming cycle C _p of the inverter 32, the pulse width is set in the vicinity of the period of the vertical synchronizing signal of the liquid crystal panel 4. Signals for setting the liquid crystal panel at a specific driving timing include a clock of a data signal (CK: clock frequency), a horizontal synchronization signal (Hsync: a period of one horizontal period), and a vertical synchronization signal (Vsync: a period of one frame). ) Etc. are used.

  FIG. 7 is a flowchart showing a driving procedure of the inverter of FIG. The inverter drive frequency is adjusted by first searching for a frequency at which the drive frequency of the backlight inverter does not interfere with the horizontal period (Hsync): 1620CK and the vertical period (Vsync): 1000Hsync (301). Next, a driving frequency that does not interfere with the driving signal of the liquid crystal panel is set for the inverter 32 (302). The cold cathode fluorescent tube 31 is driven at the set driving frequency (303).

  The drive frequency of the inverter can be set within a range of 65 Hz ± 10 Hz, for example. The dimming frequency of the inverter can be set within a range of 30 kHz to 65 kHz, for example.

  When PWM dimming of the inverter is performed, if the dimming output is 100%, noise can be prevented if the drive frequency and the drive timing of the display element do not interfere with each other. When this is done, depending on the dimming frequency, the dimming frequency and the drive signal interfere with each other, and the same noise as when the frequency of the voltage fluctuation due to the inverter drive interferes with the drive signal of the display element appears in the display element shape. May occur. In this case, interference between the dimming frequency and the driving signal is achieved by a method of setting the dimming frequency not to be used or by controlling the driving signal of the display element to change in the case of the dimming frequency. Can be avoided.

  In the above embodiment, a device comprising a gate array, a memory and an internal clock is used as the signal conversion means for converting various drive timings of the image signal into specific drive timings. However, the display device and drive method of the present invention are used. The signal conversion means is not limited to the above means, and any means that can change the drive timing can be used.

  In the present invention, the specific drive timing after conversion is not limited to the specification of the output image signal shown in the above embodiment. The specific drive timing in the present invention can be set as appropriate according to the resolution of the liquid crystal panel, the specifications of the driver, and the like.

  In the liquid crystal panel unit 2 of the above embodiment, the components of the liquid crystal panel 4, the gate driver 7, the data driver 8 and the like can be those of a conventional general liquid crystal display module. Further, in the backlight unit 3 of the above embodiment, the components of the inverter unit 32, the cold cathode fluorescent tube 31 and the like can be those of a conventional general liquid crystal display module backlight unit.

  In the above embodiment, the case where the liquid crystal panel 4 is a transmission type has been described, but the present invention is also applicable to a reflection type liquid crystal panel. For example, a light guide plate is disposed on the display surface side of the liquid crystal panel, a cold cathode fluorescent tube is disposed on the incident surface side of the light guide plate, and a reflective plate is provided on the back side of the liquid crystal panel, thereby providing a reflective liquid crystal panel. Can be configured. Further, the present invention can also be applied to a transflective liquid crystal panel between the reflective type and the transmissive type.

  Further, the lamp of the light source of the backlight is not limited to the cold cathode fluorescent tube, and any lamp that can be dimmed by an inverter can be used. The dimming by the inverter of the backlight is not limited to the PWM dimming method, and other digital dimming methods or analog dimming methods can be used.

  In the above description, the liquid crystal display module has been described as an example of a display device. However, the present invention is not limited to the liquid crystal display module, and an image is displayed by modulating light from a light source based on a signal input from the outside. The present invention can be applied to any display device having a display element to be used.

FIG. 1 is an explanatory view showing a driving method of a conventional display device. FIG. 2 is an explanatory diagram showing a driving method of the display device of the present invention. It is a block diagram which shows the structure of the liquid crystal display device as an example of the display apparatus of this invention, and has shown the structure of the liquid crystal display module provided with a transmissive | pervious liquid crystal panel. FIG. 4 is a cross-sectional view illustrating a schematic structure of a liquid crystal panel and a positional relationship of a backlight unit in the liquid crystal display device illustrated in FIG. 3. 4 is a flowchart for explaining a driving method of the liquid crystal panel unit shown in FIG. 3. It is a figure which shows the transmission waveform of the inverter used for a backlight unit. It is a flowchart for demonstrating the drive procedure of an inverter.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Liquid crystal display module 2 Liquid crystal panel unit 3 Backlight unit 4 Liquid crystal panel 5 Signal conversion means 6 External system 7 Gate driver 8 Source driver 31 Cold cathode fluorescent tube 32 Inverter 51 Gate array 52 Memory 53 Internal clock

Claims (16)

A display element for displaying an image by modulating light from a light source based on an externally input signal;
Signal conversion means for converting signals of various drive timings input from the outside into signals of specific drive timings;
A display device comprising: drive means for driving a display element based on a signal at a specific drive timing.   The display device according to claim 1, further comprising a light source unit that includes a lamp and an inverter that drives the lamp to irradiate the display element with light.   A light source unit for irradiating the display element with light includes a lamp and an inverter for driving the lamp, and is formed so that the drive frequency of the inverter and a signal at a specific drive timing for driving the display element do not interfere with each other. The display device according to claim 1.   A light source unit that includes a lamp and an inverter that drives the lamp to irradiate the display element with light, and is formed so that a dimming frequency of the inverter and a signal of a specific drive timing that drives the display element do not interfere with each other. The display device according to claim 1, wherein:   A light source unit for irradiating the display element with light comprising a lamp and a PWM dimming type inverter that drives the lamp, and a drive frequency and / or dimming frequency of the inverter and a specific drive timing for driving the display element The display device according to claim 1, wherein the display device is formed so as not to interfere.   2. The display device according to claim 1, wherein the signal conversion means includes an internal clock for generating a specific drive timing.   2. The display device according to claim 1, wherein the signal conversion means includes a memory for storing a signal input from the outside for a predetermined time.   2. The display device according to claim 1, wherein the signal for the specific drive timing is any one of a horizontal synchronization signal, a vertical synchronization signal, and a clock signal.   Various drive timing signals input from the outside are converted into specific drive timing signals, the display elements are driven based on the specific drive timing signals, and the light emitted from the light source is modulated. A method for driving a display device, characterized in that an image is displayed on the screen.   10. The method of driving a display device according to claim 9, wherein the lamp of the light source is driven by an inverter.   10. The method of driving a display device according to claim 9, wherein when the lamp of the light source is driven by an inverter, the drive frequency of the inverter and a signal at a specific drive timing for driving the display element are prevented from interfering with each other.   10. The method of driving a display device according to claim 9, wherein when the light source lamp is dimmed by the inverter, the dimming frequency of the inverter and a signal at a specific drive timing for driving the display element are prevented from interfering with each other. .   When the lamp of the light source is driven by a PWM dimming type inverter, the driving frequency of the inverter and / or the dimming frequency is prevented from interfering with a signal at a specific driving timing for driving the display element. Item 10. A display device driving method according to Item 9.   10. The method of driving a display device according to claim 9, wherein signals of various drive timings inputted from the outside are converted into signals of specific drive timings using an internal clock.   10. The method of driving a display device according to claim 9, wherein signals of various drive timings input from the outside are input to a memory, stored for a certain period of time, and then output to convert them into specific drive timings. The display device driving method according to claim 9, wherein the signal for the specific driving timing is any one of a horizontal synchronizing signal, a vertical synchronizing signal, and a clock signal.

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