KR20060077730A - Liquid crystal display - Google Patents

Abstract

The present invention relates to a liquid crystal display device.

First and second display panel portions including a plurality of pixels each including a switching element and first and second display signal lines connected to the switching element, and a first combination attached to one side of the first display panel portion. And a second coupling part attached to one side of the second display panel part, and a flexible printed circuit film to which a part of the first coupling part and a part of the second coupling part are attached. The flexible printed circuit board may include a plurality of first pads and a second pad disposed at a predetermined distance from the first pad, wherein the first and second coupling portions are respectively formed with the first and second pads. And third and fourth pads disposed at corresponding positions, respectively.

Display, Dual, Panel, COG, Integrated Chip, Pad, FPC, ACF, Solder

Description

Liquid crystal display {LIQUID CRYSTAL DISPLAY}

1 is a block diagram of a liquid crystal display according to an exemplary embodiment of the present invention.

2 is an equivalent circuit diagram of one pixel of a liquid crystal display according to an exemplary embodiment of the present invention.

3 is a schematic diagram of a display device according to an exemplary embodiment of the present invention.

FIG. 4 is an enlarged view of a partially disassembled liquid crystal display of FIG. 3.

FIG. 5 is a diagram illustrating a disassembled part of the liquid crystal display shown in FIG. 4.

The present invention relates to a liquid crystal display device.

A general liquid crystal display device includes two display panels and a liquid crystal layer having dielectric anisotropy interposed therebetween. An electric field is applied to the liquid crystal layer, and the intensity of the electric field is adjusted to adjust the transmittance of light passing through the liquid crystal layer to obtain a desired image. Such liquid crystal displays are typical among portable flat panel displays (FPDs) that are easy to carry. Among them, TFT-LCDs using thin film transistors (TFTs) as switching elements are mainly used.

Among such liquid crystal display devices, particularly small and medium-sized liquid crystal display devices such as mobile phones, active so-called dual liquid crystal display devices each having a display panel portion inside and outside are being actively developed.

Such a dual liquid crystal display device includes a flexible flexible printed circuit film (FPC) having a main display panel unit mounted therein, a sub display panel unit mounted externally, and a wiring for transmitting an input signal from the outside. And a combined FPC positioned respectively between the display panel portion and the driving FPC and between the main display portion and the driving FPC, and an integrated chip for controlling them.

The integrated chip generates a signal and a driving signal for controlling the main display panel and the sub display panel, and are mainly mounted on the main display panel in the form of a chip on glass (COG).

At this time, the connection between the main display panel or the sub-display panel and the coupling FPC or the coupling FPC and the driving FPC may be done by using a connector or by soldering. The pad is electrically connected to the pad.

For example, the connection between the display panel part and the coupling FCP mainly uses a connector called an anisotropic conductive film (ACF), and the connection between the coupling FPC and the driving FPC is performed by using a solder called RS (robot solder) or HB (hotbar). Mainly used.

In particular, when connecting by soldering, first attach the double-sided tape on the driving FPC, then attach the bonding FPC to the other side of the double-sided tape, and then connect the pad and the pads by soldering. This double sided tape holds the two pads together during soldering. However, when the double-sided tape is near the pad, the tape may be deformed by heat during the soldering operation. Since the double-sided tape must be additionally provided, the manufacturing cost increases, and a process of attaching the double-sided tape is required separately.

Therefore, the technical problem to be achieved by the present invention is to provide a liquid crystal display device that can solve the problems of the prior art.

According to an exemplary embodiment of the present invention, a liquid crystal display device includes a plurality of pixels each including a switching element and first and second display signal lines connected to the switching element, respectively. A second display panel portion, a first coupling portion attached to one side of the first display panel portion, a second coupling portion attached to one side of the second display panel portion, and a portion of the first coupling portion and the second coupling portion A flexible printed circuit board includes a portion to which the flexible printed circuit film is attached, and the flexible printed circuit board includes a plurality of first pads and a second pad disposed at a predetermined distance from the first pad. The first and second coupling parts may include third and fourth pads disposed at positions corresponding to the first and second pads, respectively.

In this case, the first and third pads are preferably connected to the wires for transmitting signals, and the second and fourth pads are not connected to the wires.

In addition, the first to fourth pads may be joined by soldering, and the second and fourth pads are preferably joined by soldering first.

In addition, the first and second coupling units may include fifth and sixth pads, respectively, and the first and second display panels may include seventh and eighth pads positioned at positions corresponding to the fifth and sixth pads, respectively. The fifth pad, the seventh pad, the sixth pad, and the eighth pad may be connected to each other by an anisotropic conductive layer.

The liquid crystal display may include a driving circuit chip for driving the first and second display panel units, and the driving circuit chip may be mounted on the first display panel unit.

DETAILED DESCRIPTION Embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention.

In the drawings, the thickness of layers, films, panels, regions, etc., are exaggerated for clarity. Like parts are designated by like reference numerals throughout the specification. When a portion of a layer, film, region, plate, etc. is said to be "on top" of another part, this includes not only when the other part is "right on" but also another part in the middle. On the contrary, when a part is "just above" another part, there is no other part in the middle.

A display device according to an exemplary embodiment of the present invention will now be described in detail with reference to the accompanying drawings.

1 is a block diagram of a liquid crystal display according to an embodiment of the present invention, FIG. 2 is an equivalent circuit diagram of one pixel of the liquid crystal display according to an embodiment of the present invention, and FIG. 3 is an embodiment of the present invention. A schematic diagram of a display device according to an example. FIG. 4 is an enlarged view of a partially disassembled liquid crystal display of FIG. 3, and FIG. 5 is a view showing a combination of disassembled parts of the liquid crystal display of FIG. 4.

As shown in FIG. 1, a liquid crystal display according to an exemplary embodiment of the present invention includes a liquid crystal panel assembly 300, a gate driver 400, a data driver 500, and a data driver 500 connected thereto. The gray voltage generator 800 connected to the signal generator 500 and a signal controller 600 for controlling the gray voltage generator 800 are included.

The liquid crystal panel assembly 300 includes a plurality of display signal lines G ₁ -G _n , D ₁ -D _m and a plurality of pixels connected to the plurality of display signal lines G ₁ -G _n , D ₁ -D _m , and arranged in a substantially matrix form. .

The display 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 data line D for transmitting a data signal. ₁ -D _m ). The gate lines G ₁ -G _n extend substantially in the row direction and are substantially parallel to each other, and the data lines D ₁ -D _m extend substantially in the column direction and are substantially parallel to each other.

Each pixel includes a switching element Q connected to a display signal line G ₁ -G _n , D ₁ -D _m , and a liquid crystal capacitor C _LC and a storage capacitor C _ST connected thereto. ). The holding capacitor C _ST can be omitted as necessary.

The switching element Q, such as a thin film transistor, is provided in the lower panel 100, and the control terminal and the input terminal are three-terminal elements, respectively, with gate lines G ₁ -G _n and data lines D ₁ -D _m . The output terminal is connected to a liquid crystal capacitor (C _LC ) and a holding capacitor (C _ST ).

The liquid crystal capacitor C _LC has two terminals, the pixel electrode 190 of the lower panel 100 and the common electrode 270 of the upper panel 200, and the liquid crystal layer 3 between the two electrodes 190 and 270. It functions as a dielectric. The pixel electrode 190 is connected to the switching element Q, and the common electrode 270 is formed on the front surface of the upper panel 200 and receives a common voltage V _com . Unlike in FIG. 2, the common electrode 270 may be provided in the lower panel 100. In this case, at least one of the two electrodes 190 and 270 may be linear or rod-shaped.

The storage capacitor C _ST , which serves as an auxiliary part of the liquid crystal capacitor C _LC , is formed by overlapping a separate signal line (not shown) and the pixel electrode 190 provided on the lower panel 100 with an insulator interposed therebetween. A predetermined voltage such as the common voltage V _com is applied to this separate signal line. However, the storage capacitor C _ST may be formed such that the pixel electrode 190 overlaps the front end gate line directly above the insulator.

On the other hand, to implement color display, each pixel uniquely displays one of the three primary colors (spatial division) or each pixel alternately displays the three primary colors over time (time division) so that the desired color can be selected by the spatial and temporal sum of these three primary colors. To be recognized. 2 shows that each pixel includes a red, green, or blue color filter 230 in a region corresponding to the pixel electrode 190 as an example of spatial division. Unlike FIG. 2, the color filter 230 may be formed above or below the pixel electrode 190 of the lower panel 100.

A polarizer (not shown) for polarizing light is attached to an outer surface of at least one of the two display panels 100 and 200 of the liquid crystal panel assembly 300.

Meanwhile, as shown in FIG. 3, the display device according to the exemplary embodiment of the present invention has two display panel portions, that is, the main display panel portion 300M and the sub display panel portion 300S, and each of the display panel portions 300M and 300S has a display panel portion. A black matrix 320M, 320S defining display areas 310M, 310S, and most of the pixels and display signal lines G ₁ -G _n , D ₁ -D _m are located within display areas 310M, 310S do. Since the upper panel 200 is smaller than the lower panel 100, a portion of the lower panel 100 is exposed and the data lines D ₁ -D _m extend to the area to be connected to the data driver 500.

The main display panel 300M and the sub display panel 300S are attached to one FPC 650 through the main coupling 680M and the sub coupling 680S, respectively.

The main display panel 300M is attached to one side of the FPC 650 via the main coupling unit 680M, and the sub display panel 300S cuts a portion of the FPC 650 into a rectangular cutout 690. It is attached to one side of through the sub coupling part 680S.

As shown in Figures 4 and 5, the FPC 650, also called an interface FPC, aligns with a wire (not shown) for transmitting signals and a rectangular pad 652 at its end. An align key 653 and a round dummy pad 655 are provided.

In addition, pads are also provided in the coupling parts 680M and 680S and the display panel parts 300M and 300S in contact with the pads of the FPC 650. Pads 682, 681, and 381 are shown. The pad 381 of the main display panel shows an input pad located below the integrated chip 700.

The main coupling part 680M is also provided with a semicircular dummy pad 685 and an alignment key 683, and the sub coupling part 680S may be provided with a round dummy pad.

At this time, when the main coupling portion 680M is coupled to the FPC 650, soldering is performed on the two dummy pads 655 and 685 in advance. The two dummy pads 655 and 685 are then attached to each other and the pads 652 and 682 are joined by soldering. Alternatively, an anisotropic conductive film may be used to electrically connect the pad 681 of the FPC 650 and the pad 381 of the main display panel 300M to each other.

The two dummy pads 655 and 685 serve as alignment keys, while fixing the FPC 650 and the coupling portion 680M.

On the other hand, the dummy pads 655 and 685 have a smaller wiring gap than the pads 652, so that the dummy pads 655 and 685 can be sufficiently arranged without providing a separate free space.

In this way, since the double-sided tape does not need to be provided or attached separately, cost can be reduced and alignment can be facilitated. In addition, deterioration due to heat of the double-sided tape can be eliminated, and the strength against tearing can be better than that of the double-sided tape.

The FPC 650 includes power supply units 750M and 750S for providing a constant current power or voltage power to the main display panel unit 300M and the sub display panel unit 300S. The power supply units 750M and 750S are provided. A power supply circuit and a predetermined resistor.

Referring back to FIG. 1, the gray voltage generator 800 generates one or two gray voltages related to the luminance of the pixel. If there are two sets, one of the sets has a positive value for the common voltage (V _com ) and the other set has a negative value.

The gate driver 400 is connected to the gate lines G ₁ -G _n of the display panel 300 to turn off the gate-on voltage V _on and the switching element Q, which can turn _{on the} switching element Q. A gate signal composed of a combination of gate off voltages V _off may be applied to the gate lines G ₁ -G _n .

The data driver 500 is connected to the data lines D ₁ -D _m of the display panel 300 to select the gray voltage from the gray voltage generator 800 and apply the gray voltage to the pixel as a data signal.

The signal controller 600 controls operations of the gate driver 400 and the data driver 500.

The signal controller 600, the gate driver 400, the data driver 500, and the gray voltage generator 800 are implemented as a single integrated chip 700 as shown in FIG. 3 to form a chip on glass (COG) method. It is attached to the main display panel part 300M.

The integrated chip 700 receives a signal from an external mobile processing unit (MPU) (not shown) through the connection unit 660 and processes a signal through the wiring provided in the FPC 650 to the main display panel unit 300M. And the sub display panel unit 300S.

The display operation of such a display device will now be described in more detail.

The signal controller 600 may control the input image signals R, G, and B and their display from an external graphic controller (not shown), for example, a vertical sync signal V _sync and a horizontal sync signal. (H _sync ), a main clock (MCLK), a data enable signal (DE) is provided. The signal controller 600 generates a gate control signal CONT1 and a data control signal CONT2 based on the input control signal and the input image signals R, G, and B, and generates the image signals R, G, and B. After appropriately processing the display panel 300 according to the operating conditions, the gate control signal CONT1 is sent to the gate driver 400, and the data control signal CONT2 and the processed image signal DAT are transferred to the data driver 500. Export.

The gate control signal (CONT1) is the gate-on scanning start instructing the start of output of a voltage (V _on) signal (STV), a gate-on voltage (V _on) on-voltage gate clock signal (CPV), and a gate for controlling the output timing of the An output enable signal OE or the like that defines the duration of V _on .

The data control signal CONT2 is a load signal LOAD and a data clock signal for applying a corresponding data voltage to the horizontal synchronization start signal STH indicating the start of input of the image data DAT and the data lines D ₁ -D _m . (HCLK). In the case of the liquid crystal display or the like shown in FIG. 2, the polarity of the data voltage with respect to the common voltage V _com (hereinafter referred to as "polarization of the data voltage" by reducing the "polarity of the data voltage with respect to the common voltage") is inverted. The inversion signal RVS may also be included.

The data driver 500 sequentially receives the image data DAT corresponding to one row of pixels according to the data control signal CONT2 from the signal controller 600, and among the gray voltages from the gray voltage generator 800. By selecting the gray scale voltage corresponding to each image data DAT, the image data DAT is converted into a corresponding data voltage and applied to the data lines D ₁ -D _m .

The gate driver 400 applies the gate-on voltage V _on to the gate lines G ₁ -G _n in response to the gate control signal CONT1 from the signal controller 600, thereby applying the gate lines G ₁ -G _n. Turn on the switching element (Q) connected to. The data voltage supplied to the data lines D ₁ -D _m is applied to the corresponding pixel through the turned-on switching element Q.

In the case of the liquid crystal display shown in FIG. 2, the difference between the data voltage applied to the pixel and the common voltage V _com is represented as the charging voltage of the liquid crystal capacitor C _LC , that is, the pixel voltage. The liquid crystal molecules vary in arrangement depending on the magnitude of the pixel voltage. As a result, the polarization of light passing through the liquid crystal layer 3 changes. This change in polarization is represented by a change in transmittance of light by polarizers attached to the display panels 100 and 200.

After one horizontal period (or “1H”) (one period of the horizontal sync signal H _sync , the data enable signal DE, and the gate clock CPV), the data driver 500 and the gate driver 400 are next. The same operation is repeated for the pixels in the row. In this manner, the gate-on voltages V _{on are} sequentially applied to all the gate lines G ₁ -G _n during one frame to apply data voltages to all the pixels. In the case of the liquid crystal display shown in FIG. 2, inverting is applied to the data driver 500 such that the next frame starts after one frame ends, and the polarity of the data voltage applied to each pixel is opposite to that of the previous frame. The state of the signal RVS is controlled ("frame inversion"). At this time, the polarity of the data voltage flowing through one data line is changed according to the characteristics of the inversion signal RVS even in one frame (eg, "row inversion", "point inversion"), or the voltage of the data voltage applied to one pixel row. The polarities can also be different (eg "heat inversion", "point inversion").

As described above, by placing a separate dummy pad to facilitate alignment and fixing the coupling parts (680M, 680S) and the FPCP (650) to facilitate the soldering operation. In addition, since the double-sided tape is not used, manufacturing cost can be reduced.

Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of rights.

Claims (6)

First and second display panel units including a plurality of pixels each including a switching element and first and second display signal lines connected to the switching element; A first coupling part attached to one side of the first display panel part; A second coupling part attached to one side of the second display panel part, and Flexible printed circuit film to which a portion of the first coupling portion and a portion of the second coupling portion are attached Including, The flexible printed circuit board includes a plurality of first pads and a second pad disposed at a predetermined distance from the first pad, The first and second coupling parts include third and fourth pads disposed at positions corresponding to the first and second pads, respectively. Liquid crystal display. In claim 1, And a wire for transmitting a signal to the first and third pads, and no wire to the second and fourth pads. In claim 2, The first to fourth pads are coupled by soldering. In claim 3, The second and fourth pads are first bonded by soldering. In claim 1, The first and second coupling portions include fifth and sixth pads, respectively, The first and second display panels may include seventh and eighth pads positioned at positions corresponding to the fifth and sixth pads, respectively. The fifth pad and the seventh pad or the sixth pad and the eighth pad are connected by an anisotropic conductive layer. Liquid crystal display. In claim 1, The liquid crystal display device includes a driving circuit chip for driving the first and second display panel parts. The driving circuit chip is mounted on the first display panel. Liquid crystal display.

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