KR20080012587A - Liquid crystal display device - Google Patents

Abstract

An LCD is provided to form pin hole areas corresponding to openings formed in a first transparent electrode according to the formation of an electric field by the first transparent electrode and a second transparent electrode, thereby enabling the liquid crystal layer of a switching panel to display a 3D image and a plane image. An LCD(Liquid Crystal Display) comprises a backlight unit(200), a switching panel(300) and a display panel(400). The backlight unit supplies light. The switching panel is disposed in the upper part of the backlight unit, and includes a first switching substrate(310), a second switching substrate(320) and a liquid crystal layer(330). The first switching substrate has a first transparent electrode(312) on the upper surface. The second switching substrate is disposed in the upper part of the first switching substrate and has plural openings(324) arranged in a grid form in the lower surface. The liquid crystal layer is interposed between the first switching substrate and the second switching substrate to form pin holes(PHA) corresponding to the openings according to the formation of an electric field by the first and second transparent electrodes. The display panel is disposed in the upper part of the switching panel and realizes a 3D(Three-Dimensional) image and a plane image according to the formation of the pin holes.

Description

Liquid crystal display {LIQUID CRYSTAL DISPLAY DEVICE}

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

FIG. 2 is a plan view illustrating a bottom surface of the second switch substrate illustrated in FIG. 1.

FIG. 3 is a cross-sectional view of a liquid crystal display when power is supplied to the first and second transparent electrodes illustrated in FIG. 1.

4 is a cross-sectional view illustrating a liquid crystal display when no power is supplied to the first and second transparent electrodes illustrated in FIG. 3.

5 is a cross-sectional view when power is supplied to the first and second transparent electrodes in the liquid crystal display according to another exemplary embodiment of the present invention.

6 is a cross-sectional view illustrating a liquid crystal display panel when no power is supplied to the first and second transparent electrodes illustrated in FIG. 5.

<Explanation of symbols for the main parts of the drawings>

100: liquid crystal display 200: backlight unit

300: switching panel 310: first switching substrate

312: first transparent electrode 320: second switching substrate

322 second transparent electrode 324 opening

330: first liquid crystal layer 340: first polarizing plate

350: second polarizing plate 400: display panel

410 TFT substrate 420 color filter substrate

430: second liquid crystal layer

The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device capable of improving light utilization efficiency of a planar image.

The liquid crystal display device is thinner and lighter than other display devices, and has advantages of low driving voltage and low power consumption. For this reason, liquid crystal displays are widely used in portable electronic devices such as mobile communication terminals, digital cameras, and electronic organizers.

In recent years, as the electronic devices that require stereoscopic images such as video and games are rapidly increased, a liquid crystal display device capable of realizing a stereoscopic image simultaneously with a planar image has been developed.

In particular, an integrated image method for generating a stereoscopic effect by displaying images at a plurality of positions on the top, bottom, left, and right sides of the image is more popular than a binocular disparity method for displaying only two images corresponding to left and right views.

In the integrated imaging method, the core technology divides the light generated from the backlight unit into a plurality of dot-shaped light and displays a different image from each point-shaped light. To this end, an integrated image type liquid crystal display generally includes a pinhole array to generate point light.

However, such a pinhole array has a problem that the liquid crystal display device interferes with display when trying to display a planar image, thereby reducing light utilization efficiency.

Accordingly, the present invention has been made in view of such a problem, and the present invention provides a liquid crystal display device capable of improving light utilization efficiency from a backlight unit when a flat image is displayed in the liquid crystal display device.

According to an aspect of the present invention, a liquid crystal display device includes a backlight unit, a switching panel, and a display panel. The backlight unit supplies light. The switching panel is disposed above the backlight unit, and has a first switching substrate having a first transparent electrode formed on an upper surface thereof, and a second opening having a plurality of openings arranged on a lower surface thereof and arranged in a lattice shape on the lower surface thereof. A second switching substrate on which a transparent electrode is formed, and a pinhole region interposed between the first switching substrate and the second switching substrate and corresponding to the opening depending on whether an electric field is formed by the first and second transparent electrodes. It includes a liquid crystal layer to make. The display panel is disposed on the switching panel, and a stereoscopic image and a planar image are implemented according to whether the pinhole region is formed.

The opening has a point shape.

The switching panel further includes a first polarizing plate disposed below the first switching substrate and a second polarizing plate disposed above the second switching substrate.

The switching panel, when the liquid crystal layer emits light having a polarization axis different from the surroundings around the opening, forms the pinhole region to implement the stereoscopic image. On the other hand, the second polarizing plate has a transmission axis in the same direction as the first polarizing plate. In this case, the liquid crystal layer allows the polarization axis of the light passing through the first polarizing plate to be transmitted as it is in the pinhole region.

Alternatively, the second polarizing plate may have a transmission axis perpendicular to the first polarizing plate. In this case, the liquid crystal layer allows the polarization axis of the light passing through the first polarizing plate to be vertically changed in the pinhole region to be transmitted.

In addition, the switching panel enables the planar image to be realized when the liquid crystal layer emits light having the same polarization axis over the entire area.

The diameter of the opening is characterized in that 90㎛ to 130㎛. In addition, the thickness of the liquid crystal layer is characterized in that 2㎛ to 6㎛.

According to the liquid crystal display, the pinhole regions corresponding to the openings formed in the first transparent electrode are formed according to whether the liquid crystal layer of the switching panel is formed by the first transparent electrode and the second transparent electrode, thereby forming a stereoscopic image. A planar image may be displayed. In particular, when displaying the planar image, by removing the pinhole regions, it is possible to prevent a reduction in the amount of light that may be generated due to the switching panel.

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

1 is a perspective view illustrating a liquid crystal display according to an exemplary embodiment of the present invention, and FIG. 2 is a plan view illustrating a bottom surface of the second switch substrate illustrated in FIG. 1.

1 and 2, the liquid crystal display 100 according to an exemplary embodiment of the present invention includes a backlight unit 200, a switching panel 300, and a display panel 400.

The backlight unit 200 includes a separate light source to supply light to the display panel 400. For example, the backlight unit 200 may include a Cold Cathode Fluorescent Light (CCFL) or a Light Emitting Diode (LED) as a light source. In addition, the backlight unit 200 may include a plurality of optical members in order to improve characteristics of light generated from the light source.

The switching panel 300 is disposed above the backlight unit 200. The switching panel 300 includes a first switching substrate 310, a second switching substrate 320, and a first liquid crystal layer 330 interposed between the first switching substrate 310 and the second switching substrate 320. do. In addition, the switching panel 300 further includes a first polarizing plate 340 and a second polarizing plate 350 on the lower portion of the first switching substrate 310 and the upper portion of the second switching substrate 320.

The switching panel 300 having such a structure serves to emit only the light desired by the user to the upper portion of the second polarizing plate 350 by using the wave property of the light generated from the backlight unit 200.

The switching panel 300 forms a first transparent electrode 312 on an upper surface of the first switching substrate 310, and forms a second transparent electrode 322 on a lower surface of the second switching substrate 320 to be interposed therebetween. The direction of the liquid crystal molecules 332 included in the first liquid crystal layer 330 is changed.

Accordingly, the switching panel 300 may allow all the light emitted from the first polarizing plate 340 to pass through the second polarizing plate 350 by changing the wave direction of the light, that is, the polarization axis of the light, and vice versa. You can also That is, the liquid crystal display device 100 transmits all of the images to display the planar image, and only partially transmits the images of the three-dimensional image.

The first transparent electrode 312 has the same area as the first switching substrate 310 and has a structure covering the entire upper surface of the first switching substrate 310. That is, the first transparent electrode 312 may be formed on the entire first switching substrate 310 through a sputtering process. The second transparent electrode 322 may also be formed in the same manner as the first transparent electrode 312.

In this case, a plurality of openings 324 are formed in the second transparent electrode 322 in order to allow the light generated from the backlight unit 200 to emit the first polarizing plate 340 in a dot shape. That is, the opening 324 has a dot shape and may be formed using a mask after the second transparent electrode 322 is formed on the entire lower surface of the second switching substrate 320.

As the number of the openings 324 increases, the resolution of the stereoscopic image increases. If the number of the openings 324 is increased, a light source having a very high efficiency or a relatively high light generation amount is required to increase the luminance of each point-shaped light.

These openings 324 are arranged in a lattice structure with a constant distance from each other. This is to ensure that the image is uniformly displayed on the top, bottom, left and right sides of the stereoscopic image to be displayed on the display panel 400.

On the contrary, when more openings 324 are to be displayed in a specific direction, more openings 324 may be formed at positions corresponding to the above directions. Thereby, the resolution in the said direction can be raised.

The first and second transparent electrodes 312 and 322 are made of a transparent material so that light generated from the backlight unit 200 can be transmitted. For example, the first and second transparent electrodes 322 may be made of indium tin oxide (ITO).

As such, the liquid crystal display 100 may easily generate dot-shaped light for displaying a stereoscopic image through the openings 324 formed in the second transparent electrode 322, and to display a planar image. The light emitted from the first polarizer 340 through the switching panel 300 is emitted to the display panel 400 through the second polarizer 350, thereby improving light utilization efficiency in the planar image.

The display panel 400 includes a TFT substrate 410 having a thin film transistor (TFT) formed in a matrix form, a color filter substrate 420 having RGB pixels formed in a thin film form while facing the TFT substrate 410. The second liquid crystal layer 430 is interposed between the TFT substrate 410 and the color filter substrate 420. The display panel 400 may form different electric fields according to positions by TFTs to change the directions of liquid crystal molecules of the second liquid crystal layer 430 to display an image of a desired gray scale.

FIG. 3 is a cross-sectional view of a liquid crystal display when power is supplied to the first and second transparent electrodes illustrated in FIG. 1.

Referring to FIG. 3, the switching panel 300 supplies power to the first transparent electrode 312 and the second transparent electrode 322 to change the direction of the liquid crystal molecules 332 of the first liquid crystal layer 330. The light is emitted only to the pinhole regions PHA corresponding to the openings 324 to display the 3D image 3D on the display panel 400.

First, the light generated by the backlight unit 200 generates natural light 10 that vibrates in all directions. Thereafter, the natural light 10 passes through the first polarizing plate 340 and emits the first polarized light 20 which oscillates in the same direction as the transmission axis 40 formed on the first polarizing plate 340. Here, the first polarization 20 has a first polarization axis 22 parallel to the transmission axis 40.

The first polarized light 20 is emitted to the second polarizer 350 via the liquid crystal molecules 332 of the first liquid crystal layer 330 and the second switching substrate 320 through the first switching substrate 310. In this case, an electric field is not formed in the first liquid crystal layer 330 corresponding to the pinhole regions PHA where the openings 324 are formed, so that the liquid crystal molecules 332 may be parallel to each other along the advancing direction of the first polarization 20. Is placed.

On the contrary, an electric field is formed in the first liquid crystal layer 330 corresponding to the regions excluding the pinhole regions PHA, and the liquid crystal molecules 332 are disposed in a twisted shape along the advancing direction of the first polarization 20. Here, the thickness t of the first liquid crystal layer 330 is 2 µm to 6 µm, and preferably 4 µm. Moreover, the diameter D of the opening part 324 is 90 micrometers-130 micrometers, Preferably it is 100 micrometers. That is, the width of the pinhole region PHA, that is, the diameter D of the opening 324 is about 30 times larger than the thickness t of the first liquid crystal layer 330.

As a result, the first polarized light 20 is emitted as it is in the pinhole regions PHA corresponding to the openings 324, and the first polarization axis 22 of the first polarized light 20 in the regions other than the pinhole regions PHA. The light is changed to the second polarization 30 having the second polarization axis 32 perpendicular to the emission.

Thereafter, the first polarization 20 and the second polarization 30 are incident on the second polarizing plate 350. The second polarizing plate 350 has the same transmission axis 40 as the first polarizing plate 340. As a result, only the first polarization 20 having the first polarization axis 22 parallel to the transmission axis 40 is emitted from the second polarization plate 350. That is, when viewed in the entirety of the second polarizing plate 350, the first polarized light 20 is emitted in a point shape as in the shape of FIG. 2.

Accordingly, the switching panel 300 applies light to the first transparent electrode 312 and the second transparent electrode 322 to emit light only to the dot-shaped pinhole regions PHA, thereby achieving a stereoscopic image of an integrated image method. An image 3D may be displayed.

4 is a cross-sectional view illustrating a liquid crystal display when no power is supplied to the first and second transparent electrodes illustrated in FIG. 3.

In the present embodiment, since the switching panel is the same as the configuration of FIG. 3 except for the control method for displaying the planar image, the same reference numerals are used, and detailed description thereof will be omitted.

Referring to FIG. 4, the switching panel 300 cuts power to the first transparent electrode 312 and the second transparent electrode 322 and maintains the liquid crystal molecules 332 of the first liquid crystal layer 330 as it is. By irradiating light regardless of 324, the planar image 2D is displayed on the display panel 400.

The first polarized light 20 emitted from the first polarizer 340 is emitted to the second polarizer 350 through the liquid crystal molecules 332 of the first liquid crystal layer 330 through the first switching substrate 310. . In this case, an electric field is not formed in the liquid crystal molecules 332 of the first liquid crystal layer 330, and all of them are disposed in parallel along the advancing direction of the first polarization 20. Thus, the first polarized light 20 is emitted as it is while passing through the first liquid crystal layer 330.

Subsequently, the first polarization 20 transmits the second polarization plate 350 having the same polarization axis as that of the first polarization plate 340. That is, the first polarized light 20 emitted from the first polarizing plate 340 is emitted to the display panel 400 through the second polarizing plate 350 without being reduced.

Therefore, the switching panel 300 cuts power to the first transparent electrode 312 and the second transparent electrode 322 to make the function of the switching panel 300 meaningless, thereby reducing the amount of light due to the switching panel 300. Can be prevented. That is, the utilization efficiency of light in the planar image 2D may be improved.

5 is a cross-sectional view when power is supplied to the first and second transparent electrodes in the liquid crystal display according to another exemplary embodiment of the present invention.

In this embodiment, the switching panel is the same as the structure described with reference to FIG. 3 except for a structure in which the first polarizing plate and the second polarizing plate each have a first transmission axis and a second transmission axis that are perpendicular to each other, and therefore use the same reference numerals. The detailed description thereof will be omitted.

Referring to FIG. 5, the switching panel 600 of the liquid crystal display device 500 includes a first transmission axis 80 and a second transmission axis 80 in which the first polarizing plate 640 and the second polarizing plate 650 are perpendicular to each other. 90, and supplies power to the first transparent electrode 612 and the second transparent electrode 622 to change the direction of the liquid crystal molecules 632 of the first liquid crystal layer 630 according to the second polarizing plate 650. The stereoscopic image 3D is displayed on the display panel 400.

First, the natural light 50 generated from the backlight unit 200 is changed to the first polarization 60 having the first polarization axis 62 parallel to the first transmission axis 80 while passing through the first polarization plate 640. It is released.

The first polarized light 60 is emitted to the second polarizer 650 via the liquid crystal molecules 632 and the second switching substrate 620 of the first liquid crystal layer 630 through the first switching substrate 610. In this case, an electric field is not formed in the first liquid crystal layer 630 corresponding to the pinhole regions PHA in which the openings 624 are formed, so that the liquid crystal molecules 632 are twisted along the advancing direction of the first polarization 60. Is placed. In addition, an electric field is formed in the first liquid crystal layer 630 corresponding to the regions excluding the pinhole regions PHA, and the liquid crystal molecules 632 are arranged in parallel along the advancing direction of the first polarization 60.

Accordingly, the first polarization 60 has a second polarization axis 72 perpendicular to the first polarization axis 62 of the first polarization 60 in the pinhole regions PHA corresponding to the openings 624. The light is changed to the polarized light 70 and emitted, and is emitted as it is in the region except the pinhole regions PHA.

Thereafter, the first polarization 60 and the second polarization 70 are incident on the second polarizing plate 650 having the second transmission axis 90. As a result, only the second polarization 70 having the second polarization axis 72 parallel to the second transmission axis 90 is emitted from the second polarization plate 650. That is, when viewed in the entirety of the second polarizing plate 650, the second polarization 70 is emitted in a point shape as in the shape of FIG. 2. Accordingly, the switching panel 600 may display the stereoscopic image 3D of the integrated image method as in FIG. 3.

6 is a cross-sectional view illustrating a liquid crystal display panel when no power is supplied to the first and second transparent electrodes illustrated in FIG. 5.

In the present embodiment, since the switching panel 600 is the same as the configuration of FIG. 5 except for the control method for displaying the planar image, the same reference numerals are used, and detailed description thereof will be omitted.

Referring to FIG. 4, the switching panel 600 cuts off power to the first transparent electrode 612 and the second transparent electrode 622 and emits light regardless of the opening 624. The planar image 2D is displayed.

The first polarized light 60 having the first polarization axis 62 emitted from the first polarizer 640 passes through the liquid crystal molecules 632 of the first liquid crystal layer 630 through the first switching substrate 610. It is emitted to the polarizing plate 650. At this time, no electric field is formed in the liquid crystal molecules 632 of the first liquid crystal layer 630, and all of them are twisted along the advancing direction of the first polarization 60. As a result, the first polarized light 60 is changed into a second polarized light 70 having a second polarized light axis 72 perpendicular to the first polarized light axis 62 while passing through the first liquid crystal layer 630 and is emitted.

Thereafter, the second polarized light 70 is incident on the second polarizer 650. At this time, since the second polarization axis 72 is the same as the second transmission axis 90 of the second polarization plate 650, the second polarization 70 transmits the second polarization plate 650 as it is. That is, only the polarization axis of the first liquid crystal layer 630 is emitted from the first polarizing plate 640, and only the polarization axis is changed in the first liquid crystal layer 630, and the display panel 400 passes through the second polarizing plate 650. It is coming out.

Accordingly, the switching panel 600 cuts off power to the first transparent electrode 612 and the second transparent electrode 622 to prevent the amount of light due to the switching panel 600 from being reduced as shown in FIG. 4. .

According to the liquid crystal display, the pinhole regions corresponding to the openings formed in the first transparent electrode are formed according to whether the liquid crystal layer of the switching panel is formed by the first transparent electrode and the second transparent electrode, thereby forming a stereoscopic image. A planar image may be displayed.

In particular, when displaying the planar image, by removing the pinhole regions, it is possible to prevent a reduction in the amount of light that may be generated due to the switching panel. Therefore, the utilization efficiency of light in a planar image can be improved.

Although the detailed description of the present invention described above has been described with reference to preferred embodiments of the present invention, those skilled in the art or those skilled in the art will have the idea of the present invention described in the claims to be described later. And it will be understood that the present invention can be modified and changed in various ways without departing from the technical scope.

Claims (11)

A backlight unit for supplying light; A first switching substrate disposed on the backlight unit and having a first transparent electrode formed on an upper surface thereof, and a second transparent electrode formed on the lower surface of the first switching substrate and having a plurality of openings arranged in a lattice form on a lower surface thereof; A liquid crystal layer interposed between the second switching substrate and the first switching substrate and the second switching substrate and forming a pinhole region corresponding to the opening depending on whether an electric field is formed by the first and second transparent electrodes; A switching panel comprising; And And a display panel disposed on the switching panel and configured to display a stereoscopic image and a planar image according to whether the pinhole region is formed. The liquid crystal display of claim 1, wherein the opening has a dot shape. The method of claim 2, wherein the switching panel A first polarizer disposed under the first switching substrate; And And a second polarizer disposed on the second switching substrate. The liquid crystal display of claim 3, wherein the switching panel is configured such that the pinhole region is formed when the liquid crystal layer emits light having a different polarization axis from the surroundings of the opening. Display. The liquid crystal display device according to claim 4, wherein the second polarizing plate has a transmission axis in the same direction as the first polarizing plate. The liquid crystal display of claim 5, wherein the liquid crystal layer allows the polarization axis of the light passing through the first polarizing plate to be transmitted as it is in the pinhole region. The liquid crystal display of claim 4, wherein the second polarizing plate has a transmission axis perpendicular to the first polarizing plate. The liquid crystal display device according to claim 7, wherein the liquid crystal layer allows the polarization axis of the light passing through the first polarizing plate to be vertically changed in the pinhole region and transmitted. The liquid crystal display of claim 3, wherein the switching panel is configured to implement the planar image when the liquid crystal layer emits light having the same polarization axis with respect to the entire area. The liquid crystal display device according to claim 1, wherein the opening has a diameter of 90 µm to 130 µm. The liquid crystal display device according to claim 10, wherein the liquid crystal layer has a thickness of 2 µm to 6 µm.

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