KR100839411B1 - Liquid crystal display device - Google Patents

Abstract

The present invention provides a liquid crystal display device that increases display dynamics, lowers power consumption, and is advantageous for large size by increasing a dynamic contrast ratio of a screen. The liquid crystal display according to the present invention is a liquid crystal panel assembly having a plurality of pixels in a row direction and a column direction, and a back having a smaller number of pixels positioned at the rear of the liquid crystal panel assembly than the liquid crystal panel assembly in the row direction and the column direction. It includes a light unit. The backlight unit further includes scan electrodes positioned along one of the row and column directions, and data electrodes positioned along the other direction, and the scan electrodes and the data electrodes have different intensities for each pixel. Emits light.

Liquid crystal panel, backlight unit, field emission array, electron emission unit, scan electrode, data electrode, fluorescent layer

Description

Liquid crystal display {LIQUID CRYSTAL DISPLAY DEVICE}

1 is an exploded perspective view of a liquid crystal display according to an exemplary embodiment of the present invention.

FIG. 2 is a partially cutaway perspective view of the liquid crystal panel assembly shown in FIG. 1.

3 is a partially cutaway perspective view of the backlight unit according to the first embodiment of the present invention.

4 is a partial cross-sectional view of the fourth substrate and the electron emission unit illustrated in FIG. 3.

5 is a partial plan view of an electron emission unit of a backlight unit according to a second embodiment of the present invention.

6 is a partially cutaway perspective view of a backlight unit according to a third exemplary embodiment of the present invention.

7 is a block diagram of a configuration for driving a liquid crystal display according to an exemplary embodiment of the present invention.

The present invention relates to a liquid crystal display device, and more particularly, to a transmissive liquid crystal panel assembly and a backlight unit for providing light to the liquid crystal panel assembly.

A liquid crystal display device, which is a type of flat panel display device, is a display device that realizes a predetermined image by varying light transmittance for each pixel by using dielectric anisotropy of a liquid crystal whose twist angle changes according to an applied voltage. Such a liquid crystal display device has advantages such as light weight, thickness, and low power consumption compared to a cathode ray tube, which is a typical image display device.

The liquid crystal display basically includes a liquid crystal panel assembly and a backlight unit positioned behind the liquid crystal panel assembly to provide light to the liquid crystal panel assembly.

When the liquid crystal panel assembly is composed of an active liquid crystal panel assembly, the liquid crystal panel assembly includes a pair of transparent substrates, a liquid crystal layer positioned between the transparent substrates, a polarizing plate disposed on the outer surfaces of the transparent substrates, and either transparent A color filter that provides red, green, and blue colors to the common electrode provided on the inner surface of the substrate, the pixel electrodes and switching elements provided on the inner surface of the other transparent substrate, and the three sub-pixels constituting one pixel. And the like.

The liquid crystal panel assembly receives light emitted from the backlight unit and transmits or blocks the light by the action of the liquid crystal layer to realize a predetermined image.

The backlight unit may be classified according to the type of light source, and one of them is known as a cold cathode fluorescent lamp (CCFL). Since the CCFL is a line light source, the light generated from the CCFL can be evenly distributed toward the liquid crystal panel assembly through the optical members such as the diffusion sheet, the diffusion plate, and the prism sheet.

However, in the CCFL method, since light generated in the CCFL passes through the optical member, significant light loss occurs. In general, in the CCFL type liquid crystal display, the light passing through the liquid crystal panel assembly is known to correspond to about 3 to 5% of the CCFL generated light. In addition, the CCFL type backlight unit consumes a large portion of the total power consumption of the liquid crystal display due to large power consumption, and it is difficult to apply to a large liquid crystal display device having a size of 30 inches or more because of the large area of the CCFL structure.

As a conventional backlight unit, a light emitting diode (LED) method is known. A plurality of LEDs are usually provided as a point light source, and are combined with optical members such as a reflective sheet, a light guide plate, a diffusion sheet, a diffusion plate, and a prism sheet to constitute a backlight unit.

This LED method has the advantages of fast response speed and excellent color reproducibility, but has a disadvantage of high price and large thickness.

As such, the conventional backlight unit has its own problems depending on the type of light source. In addition, since the conventional backlight unit is always turned on at a constant brightness when the liquid crystal display is driven, it is difficult to meet the image quality improvement required for the liquid crystal display.

For example, when the liquid crystal panel assembly displays an arbitrary screen including a bright portion and a dark portion in accordance with an image signal, the backlight unit displays the liquid crystal panel pixels portion displaying the bright portion and the liquid crystal panel pixels displaying the dark portion. If the light of different intensity is provided to the part, it is possible to realize a screen having excellent dynamic contrast.

However, the above-described backlight unit cannot implement the above functions, and thus the conventional liquid crystal display has a limitation in increasing the dynamic contrast ratio of the screen.

Accordingly, an aspect of the present invention is to solve the above problems, and an object of the present invention is to provide a liquid crystal display device capable of realizing excellent screen quality by increasing a dynamic contrast ratio of a screen.

Another object of the present invention is to provide a liquid crystal display which can reduce power consumption of a backlight unit and minimize light loss caused by an optical member.

In order to achieve the above object, the present invention,

A liquid crystal panel assembly having a plurality of pixels in a row direction and a column direction, and a backlight unit having a smaller number of pixels located at the rear of the liquid crystal panel assembly in the row direction and the column direction than the liquid crystal panel assembly, The unit further includes scan electrodes positioned along one of the row and column directions and data electrodes positioned along the other direction, and the light having different intensity for each pixel is generated by the scan electrodes and the data electrodes. Provided is a liquid crystal display device that emits light.

The liquid crystal panel assembly may have M pixels along a row direction and N pixels along a column direction, and M and N may each be defined as an integer of 240 or more.

The backlight unit may have M 'pixels along a row direction and N' pixels along a column direction, and M 'and N' may be defined as any one of 2 to 99, respectively.

One pixel of the backlight unit may have a size of 2 to 50 mm in at least one of a row direction and a column direction.

One pixel of the backlight unit may include one scan electrode and one data electrode, or may include a plurality of scan electrodes and a plurality of data electrodes. In the latter case, the plurality of scan electrodes are electrically connected to each other, and the plurality of data electrodes are electrically connected to each other.

One pixel of the backlight unit may be a field emission array type electron emission device. The field emission array type electron emission device may include an electron emission unit electrically connected to one of the scan electrode and the data electrode, and the electron emission unit may include at least one of a carbonaceous material and a nanometer size material.

In addition, the present invention, in order to achieve the above object,

A liquid crystal panel assembly having a plurality of pixels in a row direction and a column direction, and a backlight unit having a smaller number of pixels located at the rear of the liquid crystal panel assembly in the row direction and the column direction than the liquid crystal panel assembly, A front substrate and a rear substrate in which the unit is disposed to face each other with a vacuum region interposed therebetween, scan electrodes positioned along one of the row and column directions on the rear substrate, and the other of the row and column directions on the rear substrate; The data electrodes positioned along the direction and combined with the scan electrodes to form a pixel, the electron emitters electrically connected to any one of the scan electrode and the data electrode, and the fluorescent layer located on one surface of the front substrate. It provides a liquid crystal display device comprising.

The electron emission unit may be formed of materials emitting electrons by an electric field, and may include at least one of a carbon-based material and a nanometer-sized material.

The scan electrodes and the data electrodes form an intersecting area with an insulating layer interposed therebetween, and one intersecting area may be located for each pixel of the backlight unit, or two or more intersecting areas may be located.

The fluorescent layer may be formed of a white fluorescent layer. On the other hand, the fluorescent layer may include red, green and blue fluorescent layers.

The front substrate may have a light diffusing function so that the front substrate itself may function as a diffusion plate, and a diffusion plate may be attached to one surface of the front substrate facing the liquid crystal panel assembly.

In addition, the present invention, in order to achieve the above object,

A display unit including a plurality of pixels defined by a plurality of gate lines, a plurality of data lines and gate lines and data lines, each pixel having a pixel circuit, a gate driver for applying a gate signal to each of the plurality of gate lines, A data driver for applying a data signal to each of the data lines of the data line; receiving an image signal from an external source; generating a gate driving signal and a data driving signal corresponding to the image signal; A liquid crystal display comprising a signal control unit applied to a data driver,

A plurality of light emitting pixels defined by the scan lines and column lines, a scan driver for transmitting a scan signal to each of the plurality of scan lines, and a column to each of the plurality of column lines A backlight unit may further include a backlight unit including a column driver configured to transmit a signal, and the plurality of light emitting pixels may correspond to at least two of the plurality of pixels.

The signal controller generates a scan driver control signal and a column driver control signal using an image signal, and the backlight unit may express a gray level of 2 to 8 bits for each light emitting pixel.

The plurality of pixels may be formed of M pixels along a gate line and N pixels along a data line, and M and N may each be defined as an integer of 240 or more.

The plurality of light emitting pixels may be formed of M ′ pixels along a scan line and N ′ light emitting pixels along a column line, and M ′ and N ′ may be defined as any one of 2 to 99, respectively. .

The light emitting pixel may be a field emission array type electron emission device.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is an exploded perspective view of a liquid crystal display according to an exemplary embodiment of the present invention.

Referring to the drawings, the liquid crystal display device 100 of the present embodiment has a liquid crystal panel assembly 10 having arbitrary pixels along the row direction and the column direction, and smaller than the liquid crystal panel assembly 10 along the row direction and the column direction. It includes a backlight unit 40 having a number of pixels and positioned behind the liquid crystal panel assembly 10 to provide light to the liquid crystal panel assembly 10.

Here, the row direction may be defined as one direction of the liquid crystal display 100, for example, a horizontal direction of the screen implemented by the liquid crystal panel assembly 10 (for example, the x-axis direction in the drawing), and the column direction may be defined as the liquid crystal display. Another direction of 100 may be defined as, for example, a vertical direction (for example, y-axis direction in the drawing) of the screen implemented by the liquid crystal panel assembly 10.

The number of pixels of the liquid crystal panel assembly 10 and the number of pixels of the backlight unit 40 in the row direction are referred to as M and M ', respectively, and the number of pixels and the backlight unit of the liquid crystal panel assembly 10 in the column direction ( When the number of pixels 40 is N and N ', respectively, the resolution of the liquid crystal panel assembly 10 may be expressed as M × N, and the resolution of the backlight unit 40 may be expressed as M ′ × N ′.

In the present exemplary embodiment, M and N representing the number of pixels of the liquid crystal panel assembly 10 may be defined as integers of 240 or more, respectively, and M 'and N' representing the number of pixels of the backlight unit 40 are 2 to 99, respectively. Can be defined as any one of the integers. The backlight unit 40 is formed of a self-luminous display panel having a resolution of M '× N'.

Thus, one pixel of the backlight unit 40 is positioned corresponding to two or more pixels of the liquid crystal panel assembly 10. In addition, the pixels of the backlight unit 40 are individually controlled on / off and light emission intensity by driving electrodes arranged in a matrix form, for example, scan electrodes and data electrodes positioned in directions perpendicular to each other.

In this embodiment, one pixel of the backlight unit 40 is formed of a field emission array (FEA) type electron emission device.

The FEA type electron emission device includes a scan electrode and a data electrode, an electron emission part and a fluorescent layer electrically connected to any one of the scan electrode and the data electrode. The electron emission part may be made of a material having a low work function or a high aspect ratio, for example, a carbon-based material or a nanometer (nm) size material.

The FEA type electron emitting device forms an electric field around the electron emitting part by using the voltage difference between the scan electrode and the data electrode to emit electrons therefrom, and excites the fluorescent layer with the emitted electrons to display visible light having an intensity corresponding to the electron beam emission amount. Release.

FIG. 2 is a partially cutaway perspective view of the liquid crystal panel assembly shown in FIG. 1.

Referring to the drawings, the liquid crystal panel assembly 10 includes a transparent first substrate 12 and a second substrate 14 disposed opposite to each other, and a liquid crystal injected between the first substrate 12 and the second substrate 14. A layer 16, a common electrode 18 located on an inner surface of the first substrate 12, pixel electrodes 20 and switching elements 22 located on an inner surface of the second substrate 14. do. Sealing members (not shown) are positioned at edges of the first substrate 12 and the second substrate 14.

The first substrate 12 is the front substrate of the liquid crystal panel assembly 10, and the second substrate 14 is the rear substrate of the liquid crystal panel assembly 10. On the outer surface of the first substrate 12 and the second substrate 14, a pair of polarizing plates 24, 26 whose polarization axes are perpendicular to each other are positioned. The inner surface of the first substrate 12 on which the common electrode 18 is located and the inner surface of the second substrate 14 on which the pixel electrodes 20 and the switching elements 22 are positioned are covered with the alignment layer 28. .

On the inner surface of the second substrate 14, a plurality of gate lines 30 for transmitting a gate signal (also referred to as a "scan signal") and a plurality of data lines 32 for transmitting a data signal are formed. The gate lines 30 are located next to each other along the row direction, and the data lines 32 are located next to each other along the column direction.

One pixel electrode 20 is positioned for each sub-pixel, and each sub-pixel includes a switching element 22 connected to the gate line 30 and a data line 32, and a liquid crystal connected to the switching element 22. Capacitor Clc (not shown) and sustain capacitor Cst (not shown) are formed. Holding capacitor Cst can be omitted as needed.

The switching element 22 may be formed of a thin film transistor, the control terminal and the input terminal of which are connected to the gate line 30 and the data line 32, respectively, and the output terminal of which is connected to the liquid crystal capacitor Clc.

The color filter 34 is disposed between the first substrate 12 and the common electrode 18. The color filter 34 is composed of red, green, and blue filters corresponding to one sub-pixel, and three sub-pixels in which three filters of red, green, and blue are located constitute one pixel.

When the thin film transistor, which is the switching element 22, is turned on in the liquid crystal panel assembly 10 having the above-described configuration, an electric field is formed between the pixel electrode 20 and the common electrode 18. The twist angle of the liquid crystal molecules positioned in the liquid crystal layer 16 is changed by this electric field to control a light transmission amount for each sub-pixel, thereby implementing a predetermined color image.

A first embodiment of the backlight unit will be described with reference to FIGS. 3 and 4, and a second embodiment of the backlight unit will be described with reference to FIG. 5. In both embodiments, the backlight unit consists of an FEA type electron emission display panel including FEA type electron emission elements.

3 is a partial cutaway perspective view of the backlight unit according to the first embodiment, and FIG. 4 is a partial cross-sectional view of the fourth substrate and the electron emission unit illustrated in FIG. 3.

Referring to the drawings, the backlight unit 40 includes a third substrate 42 and a fourth substrate 44 which are disposed to face each other at a predetermined interval. The sealing member 46 is disposed at the edges of the third substrate 42 and the fourth substrate 44 to bond the two substrates, and the inner space is evacuated with a vacuum of approximately 10 ⁻⁶ Torr to provide the third substrate 42 with the third substrate 42. The fourth substrate 44 and the sealing member 46 constitute a vacuum container.

The third substrate 42 becomes the front substrate of the backlight unit 40 facing the liquid crystal panel assembly, and the fourth substrate 44 becomes the rear substrate of the backlight unit 40. One surface of the fourth substrate 44 facing the third substrate 42 is provided with an electron emission unit 48 for electron emission, and one surface of the third substrate 42 facing the fourth substrate 44 is a light emitting unit. 50 is provided.

First, the electron emission unit 48 will be described. The electron emission unit 48 may include the cathode electrodes 52 formed in a stripe pattern along one direction of the fourth substrate 44 and the insulating layer 54. The gate electrodes 56 are formed in a stripe pattern along a direction orthogonal to the cathode electrode 52, and the electron emission units 58 electrically connected to the cathode electrode 52.

The gate electrodes 56 may be arranged side by side in the row direction of the fourth substrate 44, and may function as scan electrodes by applying a scan driving voltage. The cathode electrodes 52 may be arranged side by side along the column direction of the fourth substrate 44, and may function as a data electrode by receiving a data driving voltage.

Electron emitters 58 are formed in the cathode electrode 52 at each intersection of the cathode electrode 52 and the gate electrode 56. Openings 541 and 561 corresponding to the electron emission portions 58 are formed in the insulating layer 54 and the gate electrodes 56 to expose the electron emission portions 58 on the fourth substrate 44. In this embodiment, the intersection area of the cathode electrode 52 and the gate electrode 56 corresponds to one pixel area of the backlight unit 40.

The electron emission unit 58 is made of materials that emit electrons when an electric field is applied in a vacuum, such as a carbon-based material or a nanometer (nm) size material. The electron emission unit 58 may include, for example, carbon nanotubes, graphite, graphite nanofibers, diamonds, diamond-like carbons, C ₆₀ , silicon nanowires, or a combination thereof. Growth, chemical vapor deposition or sputtering, and the like.

On the other hand, the electron emission portion may be formed of a tip structure having a pointed tip mainly made of molybdenum (Mo) or silicon (Si).

Next, the light emitting unit 50 provided on the third substrate 42 includes a fluorescent layer 60 and an anode electrode 62 positioned on one surface of the fluorescent layer 60. The fluorescent layer 60 may be formed of a white fluorescent layer or a combination of red, green, and blue fluorescent layers. In the figure, the first case is illustrated.

The white fluorescent layer may be formed on the entirety of the third substrate 42 or may be divided and positioned in a predetermined pattern so that one white fluorescent layer is positioned in each pixel area. The red, green, and blue fluorescent layers may be divided and positioned in a predetermined pattern in one pixel area.

The anode electrode 62 may be formed of a metal film such as aluminum (Al) covering the surface of the fluorescent layer 60. The anode electrode 62 is an acceleration electrode for attracting an electron beam, and is applied with a high voltage (a positive DC voltage of approximately several thousand volts) to maintain the fluorescent layer 60 in a high potential state, and among the visible light emitted from the fluorescent layer 60. The visible light emitted toward the fourth substrate 44 is reflected toward the third substrate 42 to increase the brightness of the screen.

In the above-described configuration, the FEA type electron emission device includes a cathode electrode 52, a gate electrode 56, electron emission portions 58, and a corresponding fluorescent layer 60 constituting one pixel.

In the above configuration, when a predetermined driving voltage is applied to the cathode electrodes 52 and the gate electrodes 56, an electric field is formed around the electron emission section 58 in the pixel region in which the voltage difference between the two electrodes is greater than or equal to the threshold. Electrons are emitted. The emitted electrons are attracted by the high voltage applied to the anode electrode 62 and collide with the corresponding fluorescent layer 60 to emit light. The emission intensity of the pixel-specific fluorescent layer 60 corresponds to the electron beam emission amount of the pixel.

5 is a partial plan view of the electron emission unit 48 'of the backlight unit according to the second embodiment.

Referring to the drawings, in this embodiment, two or more intersection regions of the cathode electrode 52 'and the gate electrode 56' are combined to form one pixel region A. Referring to FIG. In this case, when two or more cathode electrodes 52 'and two or more gate electrodes 56' are combined to form one pixel region A, the two or more cathode electrodes 52 'are formed. Electrically connected to each other to receive the same driving voltage, two or more gate electrodes 56 'are also electrically connected to each other to receive the same driving voltage.

To this end, the two or more cathode electrodes 52 ′ and the two or more gate electrodes 56 ′ extend to the edge of the fourth substrate to form a connection member such as a flexible printed circuit board (FPCB). Ends (not shown) may be connected to each other.

In the drawing, as an example, nine crossing regions where three cathode electrodes 52 'and three gate electrodes 56' intersect form one pixel region A is illustrated.

In both the back light unit of the first embodiment and the back light unit of the second embodiment, the compression force applied to the vacuum container is supported between the third substrate 42 and the fourth substrate 44 and the distance between the two substrates is maintained. Spacers 64 (see Fig. 4) are arranged to keep the constant. The spacers 64 are preferably located outside the pixel area, not in the center of the pixel area.

In addition, if necessary, the third substrate 42 itself, which is a front substrate, may have a light diffusing function to function as a diffusion plate, and as shown in FIG. 6, an outer surface of the third substrate 42 facing the liquid crystal panel assembly. A diffuser plate 66 having a light diffusing function may be located in the.

As described above, the liquid crystal display 100 of the present exemplary embodiment uses a kind of low resolution display panel having a smaller number of pixels than the liquid crystal panel assembly 10 as the backlight unit 40. The backlight unit 40 is driven by a passive matrix method using scan electrodes and data electrodes, and provides light of appropriate intensity to pixels of the liquid crystal panel assembly 10 corresponding to each pixel.

The following table tests the display quality, the manufacturing cost of the driving circuit portion, the ease of manufacture, etc. while changing the number of pixels of the backlight unit 40 for the liquid crystal panel assembly 10 having an arbitrary resolution, and is derived according to the result. The optimal number of pixels of the backlight unit 40 for each resolution of the liquid crystal panel assembly 10 is shown.

Based on the above results, it can be seen that (liquid crystal panel assembly pixel number) / (backlight unit pixel number) is preferably in the range of 240 to 5,852. If the value exceeds 5,852, the effect of improving the dynamic contrast ratio by the backlight unit is insufficient, and if the value is less than 240, the manufacturing and driving of the backlight unit becomes difficult, thereby increasing the manufacturing cost.

In addition, in the present embodiment, one pixel of the backlight unit 40 may be formed to have a size of 2 to 50 mm along the row direction and / or the column direction. If the pixel size in the row direction and / or column direction is less than 2 mm, the backlight unit 40 has a considerable number of pixels, which makes it difficult to process the circuit signal, and the pixel size in the row direction and / or column direction On the contrary, if the amount exceeds 50 mm, the backlight unit 40 has a too small number of pixels, and the image quality improvement effect of the backlight unit 40 is insufficient.

As described above, the liquid crystal display device 100 according to the present embodiment uses the backlight unit 40 having the above-described configuration, and thus, a conventional cold cathode fluorescent lamp (hereinafter referred to as 'CCFL') and a light emitting diode (hereinafter referred to as 'LED'). Compared with the backlight unit of the type, it has the following advantages.

Since the backlight unit 40 of the present embodiment is a surface light source, it does not require a plurality of optical members used for the CCFL type backlight unit and the LED type backlight unit. Therefore, in the backlight unit 40 of the present embodiment, almost no light loss occurs while passing through the optical member, and the light unit 40 does not have to emit light of excessive intensity in consideration of the light loss. Efficiency can be obtained.

In addition, the backlight unit 40 of the present embodiment has a lower power consumption than the CCFL type back light unit, and can reduce the cost by not using the optical member. Low cost In addition, the backlight unit 40 of the present embodiment can be easily applied to a large liquid crystal display device of 30 inches or more because it is easy to enlarge the size.

7 is a block diagram of a configuration for driving a liquid crystal display device.

Referring to the drawings, the liquid crystal display according to the exemplary embodiment of the present invention includes a liquid crystal panel assembly 10, a gate driver 102 and a data driver 104 connected to the liquid crystal panel assembly 10, and a data driver 104. The gray voltage generator 106 connected to the < RTI ID = 0.0 >) < / RTI >

The liquid crystal panel assembly 10 has a plurality of signal lines G ₁ -G _n , D ₁ -D _m as viewed in an equivalent circuit, and a plurality of pixels connected to the signal lines and arranged in a substantially matrix form ( PX). The signal lines G ₁ -G _n and D ₁ -D _m are a plurality of gate lines G ₁ -G _n for transmitting a gate signal (also called a “scan signal”), and a plurality of data lines for transmitting a data signal. (D ₁ -D _m ).

Each pixel PX, for example, the i-th (i = 1,2, ... n) gate line G _i and the j-th (j = 1,2, ... m) data line D _j The pixel 11 connected to includes a switching element Q connected to the signal lines G _i and D _j , a liquid crystal capacitor Clc, and a storage capacitor Cst connected thereto. Holding capacitor Cst can be omitted as needed.

The switching element Q is a three-terminal element such as a thin film transistor provided on a lower substrate (not shown), the control terminal of which is connected to the gate line G _i , and the input terminal is connected to the data line D _j . The output terminal is connected to the liquid crystal capacitor Clc and the storage capacitor Cst.

The gray voltage generator 106 generates two sets of gray voltages (or a set of reference gray voltages) related to the transmittance of the pixel PX. One of the two sets has a positive value for the common voltage Vcom, and the other set has a negative value.

A gate driver 102, the gate lines of the liquid crystal panel assembly _{(10) (G 1 -G n} ) and is connected to the gate turn-on voltage (Von) and the gate line Gate a gate signal which is a combination of a turn-off voltage (Voff) (G ₁ -G _n ).

The data driver 104 is connected to a data line of the liquid crystal panel assembly _{(10) (D 1 -D m} ), selecting a gray voltage from the gray voltage generator 106 and the data lines them as data signals (D ₁ - D _m ). However, when the gray voltage generator 106 provides only a predetermined number of reference gray voltages instead of providing all of the voltages for all grays, the data driver 104 divides the reference gray voltages and thus the gray voltages for all grays. Generate and select the data signal from it.

The signal controller 108 controls the gate driver 102, the data driver 104, the backlight unit controller 110, and the like. The signal controller 108 receives an input image signal R, G, B and an input control signal for controlling the display thereof from an external graphic controller (not shown).

The input image signals R, G, and B contain luminance information of each pixel PX, and luminance has a predetermined number, for example, 1024 (= 2 ¹⁰ ), 256 (= 2 ⁸ ), or 64 ( = 2 ⁶ ) There are grays. Examples of the input control signal include a vertical sync signal Vsync, a horizontal sync signal Hsync, a main clock MCLK, and a data enable signal DE.

The signal controller 108 appropriately processes the input image signals R, G, and B based on the input image signals R, G, and B and the input control signals according to the operating conditions of the liquid crystal panel assembly 10, and controls the gate. After generating the signal CONT1 and the data control signal CONT2, the gate control signal CONT1 is sent to the gate driver 102, and the data control signal CONT2 and the processed image signal DAT are transmitted to the data driver Export to 104). In addition, the signal controller 108 transmits the gate control signal CONT1, the data control signal CONT2, and the processed image signal DAT to the backlight unit controller 110.

The backlight unit 40 ′ includes a backlight unit controller 110, a column driver 112, a scan driver 114, and a backlight display unit 116.

The backlight display unit 116 may include a plurality of scan lines S ₁ -S _p for transmitting a scan signal, a plurality of column lines C ₁ -C _q for transferring a column signal, and a plurality of light emitting pixels EPX. Include. Each of the plurality of light emitting pixels EPX is positioned in a region defined by scan lines S ₁ -S _p and column lines C ₁ -C _q intersecting the scan lines. Scan lines S ₁ -S _p are connected to scan driver 114, and column lines C ₁ -C _q are connected to column driver 112. The scan driver 114 and the column driver 112 are connected to the backlight unit controller 110 to operate according to the control signal of the backlight unit controller 110.

The plurality of scan lines S ₁ -S _p are the scan electrodes of the above-described backlight unit, the column lines C ₁ -C _q are the data electrodes, and each of the light emitting pixels EPX emits FEA electrons. Consists of elements.

The backlight unit controller 110 generates and transmits a scan driver control signal CS that controls the scan driver 114 using the gate control signal CONT1. A column driver control signal CC is generated using the data control signal, and a column signal CLS corresponding to the image signal DAT is generated. The generated column driver control signal CS and the column signal CLS are transmitted to the column driver 112. The backlight unit controller 110 generates luminance information for each pixel of the backlight unit from the image signal DAT of one frame, and generates a column signal CLS according to the generated luminance information.

The scan driver 114 sequentially applies a scan signal having a predetermined pulse to the scan lines S ₁ -S _p based on the received scan driver control signal. The column driver 112 applies a driving voltage corresponding to the color signal to each column line C ₁ -C _q according to the input column driver control signal.

By the above-described configuration, the backlight display unit 116 receives a driving signal synchronized with the image signal, emits light of an appropriate intensity according to luminance information of each pixel, and provides the same to the liquid crystal panel assembly 10. Each of the light emitting pixels EPX of the backlight display unit 116 is preferably driven to enable gray scale representation of 2 to 8 bits.

As a result, when the liquid crystal panel assembly 10 displays a screen of different brightness for each position, the backlight unit 40 'provides strong light to the areas of the liquid crystal panel assembly 10 pixels that display the bright portion, Weak light may be provided to the portions of the liquid crystal panel assembly 10 pixels that display the portion. In addition, the light emitting pixels of the backlight unit 40 ′ corresponding to the pixels of the liquid crystal panel assembly 10 displaying black may be turned off.

As a result, the liquid crystal display of the present embodiment may improve the dynamic contrast of the screen through the above-described process.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications and changes can be made within the scope of the claims and the detailed description of the invention and the accompanying drawings. Naturally, it belongs to the range of.

As described above, the liquid crystal display according to the present invention uses a display panel having a lower resolution than that of the liquid crystal panel as a backlight unit, thereby improving display quality by increasing the dynamic contrast ratio of the screen. In addition, the liquid crystal display according to the present invention can reduce the total power consumption by reducing the power consumption of the backlight unit, and can be easily manufactured as a large display device of 30 inches or more according to the size of the backlight unit.

Claims (32)

A liquid crystal panel assembly having a plurality of pixels along the row direction and the column direction; And A backlight unit positioned behind the liquid crystal panel assembly, the backlight unit having a smaller number of pixels in the row direction and the column direction than the liquid crystal panel assembly; The backlight unit, Scan electrodes positioned along one of the row direction and the column direction; Data electrodes positioned along one of the row direction and the column direction; And Electron emitters electrically connected to any one of the scan electrodes and the data electrodes and whose electron emission amount is controlled by a scan signal applied to the scan electrodes and a data signal applied to the data electrodes. Including, And a driving signal synchronized with an image signal to emit light having an intensity according to luminance information of each pixel to provide the liquid crystal panel assembly to the liquid crystal panel assembly. The method of claim 1, The liquid crystal panel assembly has M pixels along the row direction and N pixels along the column direction, And M and N are each an integer of 240 or more. The method of claim 2, The backlight unit has M 'pixels along the row direction and N' pixels along the column direction, And M 'and N' are each an integer of 2 to 99. The method of claim 1, And one pixel of the backlight unit has a size of 2 to 50 mm in at least one of the row direction and the column direction. The method of claim 1, And a liquid crystal panel assembly and the backlight unit satisfy the following conditions. 240≤ (number of liquid crystal panel assembly pixels) / (number of backlight unit pixels) ≤5,852 The method of claim 1, And one pixel of the backlight unit includes one scan electrode of the scan electrodes and one data electrode of the data electrodes. The method of claim 1, And one pixel of the backlight unit includes two or more scan electrodes of the scan electrodes and two or more data electrodes of the data electrodes. The method of claim 7, wherein And the at least two scan electrodes are electrically connected to each other, and the at least two data electrodes are electrically connected to each other. The method of claim 1, And the electron emitter emits electrons by an electric field due to a voltage difference between the scan electrodes and the data electrodes for each pixel of the backlight unit. delete The method of claim 9, And the electron emitter comprises at least one of a carbon-based material and a nanometer-sized material. A liquid crystal panel assembly having a plurality of pixels along the row direction and the column direction; And A backlight unit positioned behind the liquid crystal panel assembly, the backlight unit having a smaller number of pixels in the row direction and the column direction than the liquid crystal panel assembly; The backlight unit, A front substrate and a rear substrate opposed to each other with a vacuum region interposed therebetween; Scan electrodes positioned on the rear substrate in one of the row direction and the column direction; Data electrodes positioned on the rear substrate in one of the row direction and the column direction and combined with the scan electrodes to form a pixel; Electron emission parts electrically connected to one of the scan electrodes and the data electrodes, the electron emission parts being controlled by a scan signal applied to the scan electrodes and a data signal applied to the data electrodes; And Fluorescent layer located on one surface of the front substrate Including, And a driving signal synchronized with an image signal to emit light having an intensity corresponding to luminance information of each pixel, and providing the same to the liquid crystal panel assembly. The method of claim 12, The liquid crystal display of claim 1, wherein the electron emission unit is formed of materials emitting electrons by an electric field. The method of claim 13, And the electron emitter comprises at least one of a carbon-based material and a nanometer-sized material. The method of claim 12, And at least one of the scan electrodes and the data electrodes forming an intersecting region with an insulating layer therebetween. The method of claim 15, And one intersection area for each pixel of the backlight unit. The method of claim 15, And at least two crossing regions for each pixel of the backlight unit. The method of claim 12, A liquid crystal display device wherein the fluorescent layer is a white fluorescent layer. The method of claim 12, And a fluorescent layer comprising red, green, and blue fluorescent layers. The method of claim 12, And a liquid crystal display device having a light diffusion function. The method of claim 12, And a diffusion plate in which the backlight unit is located on one surface of the front substrate facing the liquid crystal panel assembly. The method of claim 12, The liquid crystal panel assembly has M pixels along the row direction and N pixels along the column direction, And M and N are each an integer of 240 or more. The method of claim 22, The backlight unit has M 'pixels along the row direction and N' pixels along the column direction, And M 'and N' are each an integer of 2 to 99. The method of claim 12, And one pixel of the backlight unit has a size of 2 to 50 mm in at least one of the row direction and the column direction. The method of claim 12, And a liquid crystal panel assembly and the backlight unit satisfy the following conditions. 240≤ (number of liquid crystal panel assembly pixels) / (number of backlight unit pixels) ≤5,852 A liquid crystal panel assembly comprising a plurality of gate lines and a plurality of data lines and a plurality of pixels defined by the gate lines and the data lines and having respective pixel circuits; A gate driver for applying a gate signal to each of the plurality of gate lines; A data driver for applying a data signal to each of the plurality of data lines; A plurality of scan lines, a plurality of column lines, a plurality of electron emitters electrically connected to any one of the scan line and the column line, and a plurality of light emitting pixels defined by the scan line and the column line A backlight display unit; A scan driver for applying a scan signal to each of the plurality of scan lines; A column driver which applies a column signal to each of the plurality of column lines; And Receiving an image signal from an external source, generating a gate driving signal and a data driving signal corresponding to the image signal, applying the gate driving signal and the data driving signal to the gate driving unit and the data driving unit, respectively, A signal control unit generates a scan driver control signal and a column driver control signal by using a signal, and applies the scan driver control signal and the column driver control signal to the scan driver and the column driver, respectively. Including, The light emitting pixel corresponds to at least two of the plurality of pixels, and the light emitting intensity of the plurality of light emitting pixels is independently controlled by the scan signal and the column signal, and the column signal is generated corresponding to the image signal. Liquid crystal display. delete The method of claim 26, The backlight display unit displays a gray level of 2 to 8 bits for each of the light emitting pixels. The method of claim 26, The plurality of pixels, M pixels along the gate line and N pixels along the data line, And M and N are each an integer of 240 or more. The method of claim 28, The plurality of light emitting pixels, M 'light emitting pixels along the scan line and N' light emitting pixels along the column line; And M 'and N' are each an integer of 2 to 99. The method of claim 26, And the light emitting pixels are field emission array (FEA) type electron emission devices. delete

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