Image display device including barrier cell and method of fabricating the same

There are provided an image display device including a barrier cell, and a method of fabricating the same. The image display device includes: a display panel configured to display an image; and a barrier cell configured to block or transmit an image emitted from the display panel, wherein a pattern spacer for maintaining a cell gap of the barrier cell is disposed in correspondence to a white area of the barrier cell, and the white area transmits the image emitted from the display panel.

The present application claims the priority benefit of Korean Patent Application No. 10-2011-0120284 filed in the Republic of Korea on Nov. 17, 2011, which is hereby incorporated by reference.

BACKGROUND

1. Field of the Disclosure

The present disclosure relates to an image display device including a barrier cell and a method of fabricating the same, and more particularly, to an image display device including a barrier cell, capable of preventing light leakage due to spacers by adjusting the arrangement of the spacers in the barrier cell, and a method of fabricating the image display device.

2. Discussion of the Related Art

Recently, with the development of information society, demands in the display field are increasing in various forms, and various image display devices capable of implementing 3-dimensional (3D) images as well as 2-dimensional (2D) images have been developed.

Human feels depth and cubic effect of images depending on various psychological and memory factors as well as binocular disparity due to the distance between the eyes.

A 3D image display method that provides cubic effects using the physiological factor of eyes is a stereoscopic type.

The stereoscopic type is based on stereography in which when 2D associated images including disparity information are provided to left and right eyes that are about 65 mm away from each other, the brain combines the 2D associated images to create spatial information before and after a display plane, thereby expressing the cubic effect.

The method of expressing cubic effects can be classified into a glasses-type method in which a user wears special glasses, and an autostereoscopic method using a lens array, such as a parallax barrier or lenticular, on a display plane, according to the location at which the cubic effect is substantially made.

In general, the autostereoscopic method is excellent in view of 3D brightness, compared to the glasses-type method.

A stereoscopic image display device includes a display panel that displays left-eye images and right-eye images, respectively, and a viewing zone generating unit that is disposed above or below the display panel. Lately, studies into the stereoscopic image display device are actively being conducted since it allows users to view 3D images without having to use any additional means.

The viewing zone generating unit may include a lens array, such as a parallex barrier, lenticular, etc.

Particularly, in the case of using a barrier cell, whether a liquid crystal layer functions as a barrier may be determined according to whether a voltage is applied.

An image display device including a barrier cell can select a 2-dimensional (2D) mode and a 3-dimensional (3D) mode.

Hereinafter, an image display device including a barrier cell will be described with reference to drawings.

FIGS. 1 and 2are views for explaining the arrangement of spacers in a conventional barrier cell20.

As illustrated inFIG. 1, the conventional barrier cell20includes third and fourth substrates21and29that are spaced apart from each other in a manner to face each other, and a second liquid crystal layer26formed between the third and fourth substrates21and29.

A first protection layer23is formed on the third substrate21, and a plurality of first electrodes PXL are formed at intervals on the first protection layer23. A second protection layer25is formed on the first electrodes PXL, and a plurality of second electrodes Vcom are formed at intervals on the second protection layer25.

Signal lines may be formed between the third substrate21and the first protection layer23.

Each first electrode PXL may be formed in correspondence to the space between two neighboring second electrodes Vcom, and each second electrode Vcom may be formed in correspondence to the space between two neighboring first electrodes PXL.

In other words, the first electrodes PXL and the second electrodes Vcom may be alternately arranged.

A third electrode27is formed in the form of a film on the lower surface of the fourth substrate29, and a second liquid crystal layer26is formed between the third and fourth substrate21and29.

Also, black matrices BM may be formed between the fourth substrate29and the third electrode27to cover signal lines, etc.

The liquid crystal molecules of the second liquid crystal layer26may be aligned according to an electric field that is formed by voltages applied to the first electrodes PXL, the second electrodes Vcom, and the third electrode27, respectively.

First, second, and third driving voltages may be applied to the first electrodes PXL, the second electrodes Vcom, and the third electrode27, respectively.

The first, second, and third driving voltages that are applied to the barrier cell20may be a part of a pixel voltage and a common voltage that are applied to a display panel.

By appropriately adjusting the first, second, and third driving voltages, the barrier cell20may function as a parallax barrier that divides incident light of the second liquid crystal layer26to emit the divided light beams in different directions.

In the conventional barrier cell20, ball spacers BS for maintaining cell gaps are randomly arranged as shown inFIG. 1.

As a result, there is a problem in which cell gaps become non-uniform due to step heights made on the deposition surfaces of the third and fourth substrates21and29.

Also, as shown inFIG. 2, since the ball spacers BS are arranged regardless of black areas Br_B and white areas Br_W of the barrier cell20, light leakage occurs due to the ball spacers BS when a 3D image is displayed.

When a 3D image is displayed, the barrier cell20is divided into the black areas Br_B and the white areas Br_W, wherein the black areas Br_B block light emitted from the display panel, and the white areas Br_W transmit light emitted from the display panel.

Accordingly, when a 3D image is displayed, the black areas Br_B need to completely block light. However, in the conventional barrier cell20, since the ball spacers BS are arranged in areas corresponding to the black areas Br_B, light leakage occurs.

In other words, liquid crystal surrounds the ball spacers BS, and light emitted from the display panel is blocked or transmitted according to the alignment of the liquid crystal. If the anchoring force of an alignment film is weakened due to physical force during a rubbing process, light leakage may occur in black areas Br_B due to changes, etc. of the liquid crystal molecules around the ball spacers BS.

SUMMARY OF THE INVENTION

An object of the present disclosure is to provide an image display device capable of preventing light leakage due to spacers by adjusting the arrangement of the spacers in a barrier cell.

To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, there is provided a display device including: a display panel configured to display an image; and a barrier cell configured to block or transmit an image emitted from the display panel, wherein a pattern spacer for maintaining a cell gap of the barrier cell is disposed in correspondence to a white area of the barrier cell, and the white area transmits the image emitted from the display panel.

In another aspect, there is provided a method of fabricating an image display device, including: forming a display panel that displays a 2-dimensional (2D) image or a 3-dimensional image (3D) image; and forming a barrier cell that blocks or transmits an image emitted from the display panel, wherein a pattern spacer for maintaining a cell gap of the barrier cell is disposed in correspondence to a white area of the barrier cell, and the white area transmits the image emitted from the display panel.

As described above, in the image display device including the barrier cell, according to the present embodiment, by adjusting the arrangement of spacers in the barrier cell such that the spacers are arranged in correspondence to the white areas (transmission areas) of the barrier cell, light leakage due to the spacers may be reduced.

As a result, it is possible to reduce 3D crosstalk, thereby improving the quality of 3D images.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 3is a view schematically illustrating an image display device100according to an embodiment of the present invention,FIG. 4shows a display panel110and a barrier cell120in the image display device100according to the embodiment of the present invention, andFIG. 5is a view for explaining a 3-dimensional (3D) image mode in the image display device100according to the embodiment of the present invention.

As shown inFIGS. 3 and 4, the image display device100may include the display panel110, the barrier cell120, etc.

The display panel110may include first and second substrates111and119that are spaced apart from each other in a manner to face each other, and a first liquid crystal layer116formed between the first and second substrates111and119.

The display panel110may include left-eye horizontal pixel lines (not shown) Hl that display left-eye images, and right-eye horizontal pixel lines (not shown) Hr that display right-eye images.

In each of the left-eye and right-eye horizontal pixel lines Hl and Hr, red, green, and blue sub-pixel areas (R, G, B) are sequentially arranged, and the left-eye horizontal pixel lines Hl and the right-eye horizontal pixel lines Hr may be alternately arranged in a vertical direction (row direction) of the display panel110.

Although not shown in the drawings, on the first substrate111, gate lines (not shown) and data lines (not shown) that intersect each other to define sub-pixel areas, and thin film transistors (not shown) connected to the gate and data lines may be formed.

Also, pixel electrodes (not shown) connected to the thin film transistors and disposed in pixel areas (not shown), etc. may be formed on the first substrate111.

Also, a plurality of red, green, and blue color filters (not shown), a plurality of black matrices (not shown), etc. are formed on the second substrate119.

In the display panel110, an electric field is formed by a data voltage applied to the pixel electrodes, so that alignment of the liquid crystal molecules of the first liquid crystal layer116changes to adjust light transmission, thereby displaying an image.

The barrier cell120may include third and fourth substrates121and129, and a second liquid crystal layer126formed between the third and fourth substrates121and129.

A first protection layer123is formed on the third substrate121, and a plurality of first electrodes PXL are formed at intervals on the first protection layer123. A second protection layer125is formed on the first electrodes PXL, and a plurality of second electrodes Vcom are formed at intervals on the second protection layer125.

Each first electrode PXL is formed in correspondence to the space between two neighboring second electrodes Vcom, and each second electrode Vcom is formed in correspondence to the space between two neighboring first electrodes PXL.

In other words, the first electrodes PXL and the second electrodes Vcom may be alternately arranged.

However, the plurality of first electrodes PXL and the plurality of second electrodes Vcom may be arranged at intervals on the same layer (that is, on the third substrate121). In this case, likewise, the first electrodes PXL and the second electrodes Vcom may be alternately arranged.

A third electrode127is formed in the form of a film on the lower surface of the fourth substrate129, and a second liquid crystal layer126is formed between the third substrate121and the fourth substrate129.

The liquid crystal molecules of the second liquid crystal layer126may be aligned depending on an electric field that is formed by voltages applied to the first electrodes PXL, the second electrodes Vcom, and the third electrode127, respectively.

First, second, and third driving voltages may be applied to the first electrodes PXL, the second electrodes Vcom, and the third electrode127, respectively.

The first, second, and third driving voltages applied to the barrier cell120may be a part of a pixel voltage and a common voltage that are applied to the display panel110.

By appropriately adjusting the first, second, and third driving voltages, the barrier cell120may function as a parallax barrier that divides incident light of the second liquid crystal layer126to emit the divided light beams in different directions.

For example, areas corresponding to the first electrodes PXL may become white areas (Br_W ofFIG. 1) that transmit light without changing the alignment of liquid crystal molecules, areas corresponding to the second electrodes Vcom may become black areas (Br_B ofFIG. 1) that block light by changing the alignment of liquid crystal molecules.

The display panel driver130generates a gate control signal and a data signal using an image signal RGB, a vertical synchronization signal Vsync, a horizontal synchronization signal Hsync, a data enable signal DE, a clock signal CLK, etc., and transfers the gate control signal and the data signal to the display panel110.

The display panel driver130may be mounted on a printed circuit board (PCB).

A barrier driver140generates a barrier driving signal using an interface signal, and transfers the barrier driving signal to the barrier cell120.

The interface signal is a signal that is used for data transfer in a serial interface protocol, such as I2C, and I2C is configured with a clock signal SCL and a data signal SDA.

The barrier driver140is configured in the form of an integrated circuit (IC), and mounted on a PCB.

A system unit150transfers the image signal RGB, the vertical synchronization signal Vsync, the horizontal synchronization signal Hsync, the data enable signal DE, and the clock signal CLK to the display panel driver130, and also generates the interface signal to transfer it to the barrier driver140. The system unit150may be a TV system or a graphic card.

The image display device100may control the display panel110and the barrier cell120to operate in a 2D image mode or a 3D image mode.

For example, in the 2D image mode, the display panel110displays a 2D image, and the barrier cell120transmits the 2D image, so that the image display device100displays the 2D image.

In detail, in the 2D image mode, the first, second, and third driving voltages that are respectively applied to the first electrodes PXL, the second electrodes Vcom, and the third electrode127of the barrier cell120have no substantial voltage difference.

For example, in the 2D image mode, the first, second, and third driving voltage may be the same voltage.

As a result, since no electric field is formed in the barrier cell120, alignment of the liquid crystal molecules in the second liquid crystal layer126does not change.

Accordingly, an image emitted from the display panel110is transmitted through the barrier cell120so that a user can recognize the 2D image.

Meanwhile, in the 3D image mode, the image display device100implements a 3D image using binocular disparity.

In order to implement a 3D image using binocular disparity, a left-eye image L and a right-eye image R emitted from the display panel110need to be separately transferred to a viewer's left eye and right eye, respectively.

Accordingly, in the 3D image mode, images emitted from the display panel110are blocked or transmitted by the barrier cell120to separate left-eye images from right-eye images.

In other words, the image display device100including the barrier cell120blocks or transmits a part of images emitted from the display panel110through the barrier cell120to separate left-eye images L from right-eye images R, and transfers the left-eye images L and the right-eye images R to different viewing zones, respectively.

That is, as shown inFIG. 5, right-eye images R emitted toward a viewer's left eye, and left-eye images L emitted toward the viewer's right eye are blocked by the black areas of the barrier cell120.

Also, left-eye images L emitted toward the viewer's left eye, and right-eye images R emitted toward the viewer's right eye are transmitted through the white areas of the barrier cell120.

In this way, images output from the display panel110are blocked or transmitted by the barrier cell120so that left-eye images L are transferred to the viewer's left eye, and right-eye images R are transferred to the viewer's right eye.

In detail, in the 3D image mode, there may be a voltage difference between the first, second, and third driving voltages that are respectively applied to the first electrodes PXL, the second electrodes Vcom, and the third driving voltage.

For example, since the first driving voltage applied to the first electrodes PXL is the same as the third driving voltage applied to the third electrode127, there is no substantial voltage difference between the first electrodes PXL and the third electrode127, so that alignment of liquid crystal molecules corresponding to the first electrodes PXL does not change.

Meanwhile, since the second driving voltage applied to the second electrodes Vcom is different from the third driving voltage applied to the third electrode127, there is a voltage difference between the second electrodes Vcom and the third electrode127so that alignment of liquid crystal molecules corresponding to the first electrodes PXL changes.

As a result, in the barrier cell120, black areas that block light and white areas that transmit light are alternately arranged.

Accordingly, the barrier cell120blocks a part of an image in the black areas to separate a left-eye image from a right-eye image, and transfers the left-eye image and the right-eye image to different viewing zones, respectively, through the white areas.

The viewer recognizes the left-eye image and the right-eye image of the viewer's left and right eyes as a 3D image by binocular disparity.

FIGS. 6 and 7are views for explaining the arrangement of spacers in the barrier cell120according to the embodiment of the present invention.

As shown inFIG. 6, the barrier cell120may include the third substrate121, the fourth substrate129, and the second liquid crystal layer126formed between the third substrate121and the fourth substrate129.

The first protection layer123is formed on the third substrate121, and the plurality of first electrodes PXL are formed at intervals on the first protection layer123. The second protection layer125is formed on the first electrodes PXL, and the plurality of second electrodes Vcom are formed at intervals on the second protection layer125.

Signal lines are formed between the third substrate121and the first protection layer123, and the black matrices BM may be formed between the fourth substrate129and the third electrode127to cover the signal lines, etc.

Also, in the barrier cell120, a plurality of pattern spacers CS are formed to maintain cell gaps.

In a conventional barrier cell, since ball spacers BS for maintaining cell gaps are arranged regardless of the black areas Br_B and white areas Br_W of the barrier cell, light leakage occurs due to the ball spacers BS when a 3D image is implemented.

However, in the barrier cell120according to the present embodiment, as shown inFIGS. 6 and 7, the pattern spacers CS may be arranged in the white areas Br_W that transmit light, in correspondence to the first electrodes PXL.

That is, in the barrier cell120, since the pattern spacers CS are arranged in correspondence to the white areas Br_W while no pattern spacer CS is arranged in correspondence to the black areas Br_B, light leakage that is caused by the pattern spacers CS in the black areas Br_B may be reduced.

As a result, since the barrier cell120can prevent light leakage due to the pattern spacers CS, it is possible to reduce 3D crosstalk, thereby improving the quality of 3D images.

FIGS. 8A to 8Eare views for explaining a process of fabricating the third substrate121of the barrier cell120according to the embodiment of the present invention.

First, as shown inFIG. 8A, first and second signal lines that supply a driving voltage for driving the barrier cell120may be formed on the third substrate121which is a transparent substrate, by a first mask process.

The first and second signal lines may be formed on the edge portion of the barrier cell120. The first and second signal lines may be made of molybdenum (Mo), and formed with a thickness of 3000 Å.

Then, as shown inFIG. 8B, the first protection layer123may be formed on the first and second signal lines to isolate the first and second signal lines from the first electrodes PXL.

Next, as shown inFIG. 8C, the first electrodes PXL may be formed on the first protection layer123by a second mask process.

At this time, the first electrodes PXL may be connected to the first signal line for supplying a first driving voltage, through a first contact hole.

Then, as shown inFIG. 8D, the second protection layer125may be formed on the first electrodes PXL to isolate the first electrodes PXL from the second electrodes Vcom.

The second electrodes Vcom may be formed on the same layer (that is, on the first protection layer123) as the first electrodes PXL, without forming the second protection layer125, such that the first electrodes PXL and the second electrodes Vcom are arranged to be spaced part from each other. In this case, the first electrodes PXL and the second electrodes Vcom may be alternately formed.

Then, as shown inFIG. 8E, the second electrodes Vcom may be formed on the second protection layer125by a third mask process.

The second electrodes Vcom may be connected to the second signal line for supplying a second driving voltage, through a second contact hole.

FIGS. 9A to 9Care views for explaining a process of fabricating the fourth substrate129of the barrier cell120according to the embodiment of the present invention.

As shown inFIG. 9A, a black matrix BM may be formed on the fourth substrate129which is a transparent substrate, in correspondence to a signal line, by a fourth mask process.

Then, as shown inFIG. 9B, the third electrode127may be formed on the black matrix BM.

The third electrode127may be made of Indium Tin Oxide (ITO), and formed in the form of a film.

Next, as shown inFIG. 9C, the pattern spacers CS may be formed by a fifth mask process.

Each pattern spacer CS may be in the shape of a trapezoid, and formed with a height of 3.9 um.

At this time, by appropriately adjusting the fifth mask, the pattern spacers CS may be preferably formed in correspondence to the first electrodes PXL in the third substrate121of the barrier cell120.

As a result, in the barrier cell120, the pattern spacers CS may be arranged in the white areas Br_W that transmit light, in correspondence to the first electrodes PXL.

That is, in the barrier cell120, since the pattern spacers CS are arranged in correspondence to the white areas Br_W while no pattern spacer CS is arranged in correspondence to the black areas Br_B, it is possible to reduce light leakage that may be caused by the pattern spacers CS in the black areas Br_B.

Accordingly, in the barrier cell120, it is possible to prevent light leakage due to pattern spacers CS and reduce 3D crosstalk, thereby improving the image quality of 3D images.