Liquid crystal display device

A liquid crystal display device includes a liquid crystal module; a printed circuit board providing driving signals to the liquid crystal module; and an installation unit including first, second and third parts, wherein the first part is attached to the liquid crystal module, the second part faces the first part and is attached to the printed circuit board, and the third part connects the first and second parts.

The application claims the benefit of Korean Patent Application No. 10-2013-0103709 filed in Korea on Aug. 30, 2013, which is hereby incorporated by reference for all purposes as if fully set forth herein.

BACKGROUND

Field of the Disclosure

The disclosure relates to a liquid crystal display device, and more particularly, to a liquid crystal display device in which a digitizer is detachable.

Discussion of the Related Art

Liquid crystal display (LCD) devices are most widely used for monitors of notebook computers, monitors of personal computers and televisions due to low power consumption, thin thickness and large screen. LCD devices use the optical anisotropy and polarization properties of liquid crystal molecules of a liquid crystal layer to produce an image.

An LCD device includes two substrates spaced apart from and facing each other and a liquid crystal layer interposed between the two substrates. The alignment direction of the liquid crystal molecules is controlled by varying the intensity of an electric field applied to the liquid crystal layer, and the transmittance of light through the liquid crystal layer is changed.

The LCD devices require an additional light source because the LCD devices are not self-luminescent. Therefore, a backlight unit is disposed at a rear side of a liquid crystal (LC) panel and emits light into the LC panel, whereby discernible images can be displayed.

Backlight units are in general classified as edge type or direct type according to the position of a light source with respect to a display panel. In an edge-type backlight unit, a light source is disposed at one side or at each of two sides of a light guide plate of a backlight unit and light from the light source is reflected by the light guide plate or a reflection plate to be provided to the display panel. In a direct-type backlight unit, a plurality of light sources such as lamps is disposed directly under the display panel. The direct-type backlight unit has been widely used for LCD devices having a large screen of more than 20 inches because it does not require a light guide plate, has high utilization rate of light, is simply handled, and is not limited in a screen size.

The LC panel and the backlight unit are modularized with various mechanical components to be protected from outer impacts and to prevent light loss.

Meanwhile, a digitizer may be used as an input device of an LCD device. The digitizer recognizes (X,Y) coordinate of a display device and detects a specific content or key value.

Accordingly, a user can easily input desired values using an electromagnetic pen or probe.

Hereinafter, an LCD device including a digitizer as an input device according to the related art will be described with reference toFIG. 1.

FIG. 1is a cross-sectional view of illustrating an LCD device according to the related art.

InFIG. 1, the related art LCD device includes a cover bottom28, a backlight unit30, a liquid crystal panel10, a digitizer40, a guide panel13, and a case top15. The digitizer40is disposed between the backlight unit30and the liquid crystal panel10.

The cover bottom28encloses the liquid crystal panel10and the guide panel13.

The backlight unit30provides light to the liquid crystal panel10and includes a light guide plate24, a reflection sheet26, optical sheets22and a lamp assembly27. The lamp assembly27includes a lamp housing27aand LED lamps27b.

In the meantime, liquid crystal cells are arranged in an active matrix form between upper and lower substrates of the liquid crystal panel10. Transmittance of the liquid crystal cells is changed according to a video signal, and an image corresponding to the video signal is displayed.

A printed circuit board11is connected to the lower substrate of the liquid crystal panel10along at least an edge of the lower substrate via a connecting means12. The printed circuit board11may be bent toward a side surface of the guide panel13or a rear surface of the cover bottom28.

The case top15encloses sides and edges of the liquid crystal panel10, the guide panel13and the cover bottom28and is combined with the cover bottom28to form a liquid crystal module.

In the liquid crystal module, since the printed circuit board11is bent toward the side surface of the guide panel13or the rear surface of the cover bottom28, a bezel are of the LCD device may be decreased.

In the meantime, the digitizer40includes a sensor which detects the location indicated by the electromagnetic pen or probe.

At this time, the digitizer40detects external electromagnetic changes. Since electromagnetic fields penetrate the liquid crystal panel10, digitizer40is able to recognize movements of the electromagnetic pen over the liquid crystal panel10even if the digitizer40is disposed under the liquid crystal panel10.

By the way, when the digitizer40is installed at a rear surface of the liquid crystal module, the digitizer40may malfunction because the digitizer40is affected by interference of electromagnetic waves generated from the printed circuit board11.

However, the digitizer40is installed to the liquid crystal module, and the LCD device is released. Since the manufacturer needs to buy the digitizer40, to install the digitizer40to the liquid crystal module, and to release the LCD device including the digitizer40, the manufacturing costs increase. On the other hand, there is a problem that the user cannot decide whether or not the digitizer40is installed.

SUMMARY

Accordingly, the present invention is directed to a liquid crystal display device that substantially obviates one or more of the problems due to limitations and disadvantages of the related art.

An advantage of the present invention is to provide a liquid crystal display device which has a narrow bezel area and in which a digitizer is detachable.

To achieve these and other advantages and in accordance with the purpose of embodiments of the invention, as embodied and broadly described, a liquid crystal display device includes a liquid crystal module; a printed circuit board providing driving signals to the liquid crystal module; and an installation unit including first, second and third parts, wherein the first part is attached to the liquid crystal module, the second part faces the first part and is attached to the printed circuit board, and the third part connects the first and second parts. A digitizer is installed between the first and second parts and is detachable.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made in detail to embodiments of the present invention, an example of which is illustrated in the accompanying drawings.

FIG. 2is an exploded perspective view of an LCD device according to an embodiment of the present invention.

InFIG. 2, an LCD device according to the embodiment of the present invention includes a cover bottom128, a backlight unit130and a liquid crystal panel110sequentially disposed inside the cover bottom128, a guide panel113disposed between the backlight unit130and the liquid crystal panel110to support the liquid crystal panel110and combined with sides of the cover bottom128, a case top115fixing the guide panel113and the liquid crystal panel110, an installation unit150, and a digitizer140.

The cover bottom128is formed of a metal having relatively high heat conductivity such that heat from the inside of the device is effectively discharged, and the cover bottom128encloses the liquid crystal panel110and the guide panel113.

The backlight unit130includes a light guide plate124, a reflection sheet126, optical sheets122and a lamp assembly127. The lamp assembly127includes a lamp housing127a, which may be a printed circuit board, and LED lamps127bas a light source.

The lamp assembly127is disposed at a side surface of the light guide plate124. A lamp assembly may be disposed at each of opposite side surfaces of the light guide plate124. The light guide plate124changes paths of light emitted from the LED lamps127btoward the liquid crystal panel110and also changes a linear light source into a surface light source. The reflection sheet126reflects light passing through a rear surface of the light guide plate toward the liquid crystal panel110.

The optical sheets122, which may include a diffuser sheet and a prism sheet, are disposed over the light guide plate124. The optical sheets122improve uniformity of the surface light source from the light guide plate124.

In the meantime, liquid crystal cells are arranged in an active matrix form between upper and lower substrates of the liquid crystal panel110.

Gate lines and data lines crossing each other to define pixel regions are formed on the lower substrate, and a thin film transistor is formed at each pixel region. A liquid crystal capacitor is connected to the thin film transistor.

Transmittance of the liquid crystal cells is changed according to a video signal, and an image corresponding to the video signal is displayed.

The liquid crystal panel110is divided into a display area displaying the image and a non-display area surrounding the display area.

A printed circuit board111is connected to the lower substrate of the liquid crystal panel110along at least an edge of the lower substrate via a connecting means112such as a flexible printed circuit or a tape carrier package. The printed circuit board111may be bent toward a side surface of the guide panel113or a rear surface of the cover bottom128and may be attached to the installation unit150in a modularizing step, which is disposed at a rear surface of a liquid crystal module100.

Drive integrated circuits for driving the thin film transistors of the LCD device may be mounted on the printed circuit board111. The liquid crystal panel110and the printed circuit board111are electrically connected to each other through the connecting means112, and control signals and the video signal from the printed circuit board111are applied to the liquid crystal panel110.

The case top115has a rectangular frame shape including a plane portion and a side portion, which are perpendicularly connected to each other. The case top115encloses sides and edges of the liquid crystal panel110, the guide panel113and the cover bottom128to form the liquid crystal module100.

In the liquid crystal module100, the printed circuit board111is appropriately bent to the installation unit150, thereby decreasing a bezel area of the LCD device.

The installation unit150attached to the rear surface of the liquid crystal module100functions as a hinge such that the printed circuit board111is swung while being fixed to the liquid crystal module100. The installation unit150includes two parts, one ends of which are touched to each other to form a space therebetween. The digitizer140is installed in the space between the two parts of the installation unit150.

FIG. 3is a cross-sectional view of schematically illustrating an LCD device according to the embodiment of the present invention.

InFIG. 3, the LCD device according to the embodiment of the present invention includes a liquid crystal module100, a printed circuit board111, a connecting means112, an installation unit150, and a digitizer140. The printed circuit board111provides driving signals to the liquid crystal module100, and the connecting means electrically connects the liquid crystal module100and the printed circuit board111. The installation unit150is disposed between the liquid crystal module100and the printed circuit board111and functions as a hinge such that the printed circuit board111is fixed to the liquid crystal module100while being swung. The digitizer140is installed at the installation unit150.

Although not shown in the figure, a lot of elements including integrated circuits are mounted on the printed circuit board111. The printed circuit board111is electrically connected to a liquid crystal panel (not shown) of the liquid crystal module100, and driving signals from the printed circuit board111are provided to the liquid crystal panel to produce an image.

The digitizer140is electrically connected to the printed circuit board111. The digitizer140may be classified into resistive type, capacitive type, and electromagnetic type according to different methods of detecting a touch input of a user.

A resistive type digitizer detects a location pushed by pressure according to current amount change while a direct current voltage is applied. A capacitive type digitizer detects a selected location using capacitance coupling while an alternating current voltage is applied. An electromagnetic type digitizer detects a selected location according to voltage change while a magnetic field is applied.

Although not shown in the figure, when the digitizer140is an electromagnetic induction type, a plurality of coils in the digitizer140may detect electromagnetic change, and the digitizer140can figure out a location of an electronic pen. Therefore, even though the digitizer140is disposed under the liquid crystal module100, electromagnetic fields pass through the liquid crystal module100over the digitizer140, and the digitizer140is able to recognize movement and location of the electronic pen.

That is, since the digitizer140recognizes (X,Y) coordinate of the LCD device and detects a specific content or key value, a user is able to easily input desired values using an electromagnetic pen, which may be referred to as an electronic pen or a digital pen, or probe.

The installation unit150is closely disposed to the rear surface of the liquid crystal module100when the digitizer140is not installed and is split to form a space for the digitizer140when the digitizer140is installed.

Hereinafter, the installation unit150will be described in more detail with reference toFIG. 4.

FIG. 4is a perspective view of schematically illustrating an installation unit of an LCD device according to the embodiment of the present invention.

InFIG. 4, the installation unit150is flexible and partially bent back to have a V-like shape or a U-like shape.

The installation unit150, for example, includes a material selected from polyethersulfone (PES), polycarbonate (PC), polyimide (PI), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), poly acrylate (PAR) and fiber reinforced plastic (FRP).

The installation unit150includes a first part150aattached to the liquid crystal module100ofFIG. 3, a second part150bfacing the first part150aand attached to the printed circuit board111ofFIG. 3, and a third part150cconnecting the first part150aand the second part150b.

The digitizer140ofFIG. 3is installed between the first, second and third parts150a,150band150c.

More particularly, when the digitizer140ofFIG. 3is not installed, facing surfaces of the first and second parts150aand150bcompletely contact each other, and a thickness of the LCD device is decreased. When the digitizer140ofFIG. 3is installed, the first and second parts150aand150bare spaced apart from each other to form a space therebetween, and the digitizer140ofFIG. 3is disposed between the first and second parts150aand150b. The digitizer140ofFIG. 3may be installed on the first part150a.

Meanwhile, a double-sided tape may be attached at outer surfaces of the first part150aand150bsuch that the liquid crystal module100ofFIG. 3is attached to the first part150aand the printed circuit board111ofFIG. 3is attached to the second part150b.

At this time, to protect the integrated circuits mounted on the printed circuit board111ofFIG. 3, which is stuck to the outer surface of the second part150, a cover shield120ofFIG. 5is attached to an outer surface of the printed circuit board111ofFIG. 3. The printed circuit board111ofFIG. 3may be grounded to the liquid crystal module100ofFIG. 3.

FIG. 5is a plan view of schematically illustrating a rear side of an LCD device according to the embodiment of the present invention.

InFIG. 5, the LCD device of the present invention includes the liquid crystal module100, the installation unit150having one surface attached to the rear surface of the liquid crystal module100, the printed circuit board111attached to another surface of the installation unit150, and the cover shield120covering a surface of the printed circuit board111to protect the integrated circuits of the printed circuit board111.

At this time, in the related art LCD device, the printed circuit board is grounded to the cover bottom of the liquid crystal module. However, in the LCD device according to the embodiment of the present invention, it is difficult that the printed circuit board111is grounded to the liquid crystal module100because the installation unit150is disposed between the printed circuit board111and the liquid crystal module100.

To solve the problem, the cover shield120is divided into first and second cover shield sides120aand120b. An insulating tape is attached to the first cover shield side120afacing an area where the integrated circuits of the printed circuit board111are mounted. A conductive tape is attached to the second cover shield side120bboth ends of the first cover shield side120a.

Here, the cover shield120is also attached to the cover bottom128ofFIG. 2. That is, the conductive tape attached to the second cover shield side120bcontacts the cover bottom128ofFIG. 2, and the printed circuit board111is grounded to the cover bottom128ofFIG. 2.

Accordingly, even though the installation unit150is equipped to the rear surface of the liquid crystal module100, the printed circuit board111is grounded to the liquid crystal module100, and the printed circuit board111normally operates.

In the LCD device according to the embodiment of the present invention, since the digitizer140is disposed between the liquid crystal module100and the printed circuit board111using the installation unit150, interference from electromagnetic waves of the printed circuit board111is prevented. In addition, the printed circuit board111is bent toward the rear surface of the liquid crystal module100, and the bezel size is decreased.

Moreover, a manufacturer can reduce costs for installing the digitizer because the user decides the installation of the digitizer.

In the embodiment, the liquid crystal module is explained as an example of a display device, and other display modules such as organic light-emitting diode display modules can be used as the display device.