Stereoscopic image display device and method for manufacturing the same

Disclosed is a stereoscopic image display device and a method for manufacturing the same, which facilitates to improve picture quality and to realize wide viewing angle and high luminance of stereoscopic images by improving crosstalk of left-eye image and right-eye image, wherein the stereoscopic image display device comprises a display panel including lower and upper substrates which are bonded to each other, and are provided with a left-eye displaying area (LDA) for displaying a left-eye image of stereoscopic image, and a right-eye displaying area (RDA) for displaying a right-eye image of stereoscopic image; a light-guiding member formed in the upper substrate and overlapped with an interface between the left-eye displaying area (LDA) and the right-eye displaying area (RDA); and an optical-axis changing member formed on the upper substrate, wherein the optical-axis changing member includes a left-eye retarder corresponding to the left-eye displaying area, and a right-eye retarder corresponding to the right-eye displaying area.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of the Korean Patent Application No. 10-2010-0054009 filed on Jun. 8, 2010, which is hereby incorporated by reference as if fully set forth herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a stereoscopic image display device, and more particularly, to a stereoscopic image display device which facilitates to realize good picture quality, wide viewing angle, and good luminance by preventing crosstalk of left-eye image and right-eye image.

2. Discussion of the Related Art

With development of information society, a display device is faced with requirement for a large size and a thin profile. In order to satisfy these requirements, there is the explosive increase for various kinds of flat type display devices having advantages of thin profile, lightness in weight, and low power consumption.

The flat type display device may include a liquid crystal display device (LCD), a plasma display panel (PDP), a field emission display device (FED), a light-emitting diode display device (LED), and etc. Among the various flat panel display devices, the LCD device is widely used owing to various advantages, for example, technical development for the mass production, easiness of driving means, low power consumption, and high-quality resolution.

Recently, a user's demand for a stereoscopic image is rapidly increased so that a stereoscopic image display device capable of displaying 3D (3-dimensional) image as well as 2D (2-dimensional) image is actively developed.

The stereoscopic image display device makes left-eye image and right-eye image with a binocular parallax separately seen in both eyes of a user. That is, the stereoscopic image display device makes the left-eye image recognized only in the user's left eye, and also makes the right-eye image recognized only in the user's right eye, whereby the user can watch the stereoscopic 3D image.

However, in case of the related art stereoscopic image display device, the left-eye image expected to be seen in the user's left eye might be recognized in the user's right eye, or the right-eye image expected to be seen in the user's right eye might be recognized in the user's left eye. Thus, the related art stereoscopic image display device may have a problem of low picture quality due to crosstalk of the left-eye image and right-eye image.

SUMMARY OF THE INVENTION

Accordingly, the present invention is directed to a stereoscopic image display device and a method for manufacturing the same that substantially obviates one or more problems due to limitations and disadvantages of the related art.

An advantage of the present invention is to provide a stereoscopic image display device which facilitates to improve picture quality and to realize wide viewing angle and high luminance of stereoscopic images by improving crosstalk of left-eye image and right-eye image.

To achieve these and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, there is provided a stereoscopic image display device comprising: a display panel including lower and upper substrates which are bonded to each other, and are provided with a left-eye displaying area (LDA) for displaying a left-eye image of stereoscopic image, and a right-eye displaying area (RDA) for displaying a right-eye image of stereoscopic image; a light-guiding member formed in the upper substrate and overlapped with an interface between the left-eye displaying area (LDA) and the right-eye displaying area (RDA); and an optical-axis changing member formed on the upper substrate, wherein the optical-axis changing member includes a left-eye retarder corresponding to the left-eye displaying area, and a right-eye retarder corresponding to the right-eye displaying area.

At this time, the light-guiding member reflects the right-eye image, which is transmitted through the right-eye displaying area and is advanced to the left-eye retarder, toward the right-eye retarder; and also reflects the left-eye image, which is transmitted through the left-eye displaying area and is advanced to the right-eye retarder, toward the left-eye retarder.

Also, the light-guiding member is hollowly formed from the upper surface of the upper substrate in such a manner that a thickness of the light-guiding member is more than a half of an entire thickness of the upper substrate.

In another aspect of the present invention, there is provided a method for manufacturing a stereoscopic image display device comprising: preparing a display panel including lower and upper substrates which are bonded to each other, and are provided with a left-eye displaying area (LDA) for displaying a left-eye image of stereoscopic image, and a right-eye displaying area (RDA) for displaying a right-eye image of stereoscopic image; forming a light-guiding member overlapped with an interface between the left-eye displaying area (LDA) and the right-eye displaying area (RDA) in the upper substrate; adhering an upper polarizing plate to a front surface of the upper substrate including the light-guiding member; and forming an optical-axis changing member on the upper substrate, wherein the optical-axis changing member includes a left-eye retarder corresponding to the left-eye displaying area, and a right-eye retarder corresponding to the right-eye displaying area.

At this time, the light-guiding member is hollowly formed from the upper surface of the upper substrate in such a manner that a thickness of the light-guiding member is more than a half of an entire thickness of the upper substrate.

The process for forming the light-guiding member in the upper substrate comprises forming a light reflecting layer of aluminum or silicon in the light-guiding member.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, a stereoscopic image display device according to the present invention and a method for manufacturing the same will be described with reference to the accompanying drawings.

FIG. 1illustrates a stereoscopic image display device according to the first embodiment of the present invention.FIG. 2is a cross section view along A-A′ ofFIG. 1.

Referring toFIGS. 1 and 2, the stereoscopic image display device according to the first embodiment of the present invention comprises a display panel100, a light-guiding member200, and an optical-axis changing member300.

The display panel100comprises a lower substrate110and an upper substrate120which are bonded to each other, and are provided with a left-eye displaying area (LDA) for displaying a left-eye image of stereoscopic image, and a right-eye displaying area (RDA) for displaying a right-eye image of stereoscopic image. At this time, the lower substrate110and the upper substrate120are bonded to each other with a liquid crystal layer130interposed therebetween.

On the lower substrate110, there is a thin film transistor array112which includes a plurality of gate lines (GL), a plurality of data lines (DL), and a plurality of pixels (P).

The plurality of gate lines (GL) are arranged at fixed intervals in a first direction of the lower substrate110, wherein the plurality of gate lines (GL) are supplied with a gate signal from the external.

The plurality of data lines (DL) are arranged at fixed intervals in a second direction of the lower substrate110, wherein the second direction is perpendicular to the first direction. The plurality of data lines (DL) are supplied with a data signal from the external. At this time, the data signal may correspond to a two-dimensional image (2D image) in a 2D image mode; or may correspond to the left-eye image and right-eye image in a stereoscopic image mode.

Each of the plurality of pixels (P) is formed every pixel region defined by crossing the gate lines (GL) and data lines (DL) to each other. Each pixel (P) comprises a thin film transistor (T) which is connected with the data line (DL) adjacent to the neighboring gate line (GL); a pixel electrode (PE) which is connected with the thin film transistor (T); and a common electrode (not shown) which faces with the pixel electrode (PE).

As the thin film transistor (T) is switched-on in accordance with the gate signal supplied from the gate line (GL), the data signal supplied from the data line (DL) is supplied to the pixel electrode (PE).

The pixel electrode (PE) forms an electric field depending on the data signal supplied through the thin film transistor (T), to thereby control transmittance of light passing through the liquid crystal layer130.

The common electrode is formed between each of the pixel electrodes (PE) while being provided at a predetermined interval from the pixel electrode (PE). The common electrode is supplied with a reference voltage from the external. At this time, the common electrode may be formed on the upper substrate120being faced with the pixel electrode (PE) instead of the lower substrate110.

For the stereoscopic image mode, each horizontal line corresponding to a longitudinal direction of the gate line (GL) is divided into the left-eye displaying area (LDA) for displaying the left-eye image of the stereoscopic image, and the right-eye displaying area (RDA) for displaying the right-eye image of the stereoscopic image. For example, among the horizontal lines for the stereoscopic image mode, the odd-numbered horizontal line is set as the left-eye displaying area (LDA) to display the left-eye image, and the even-numbered horizontal line is set as the right-eye displaying area (RDA) to display the right-eye image.

The lower substrate110drives the respective pixels (P) in accordance with the gate signal supplied to the gate line (GL), and the data signal corresponding to the 2D image data or 3D (left-eye and right-eye) image data supplied to the data line (DL), to thereby control the transmittance of light through the liquid crystal layer130.

On the upper substrate120, there are a plurality of color filters (CF), a black matrix (BM), and an overcoat layer122.

The plurality of color filters (CF) include red (R), green (G), and blue (B) color filters which correspond to the plurality of pixels (P). The red (R), green (G), and blue (B) color filters and the corresponding red, green, and blue pixels (P) constitute a unit pixel for displaying a color image. The plurality of color filters (CF) may be arranged in such a manner that the different kinds of the color filters (CF) may be repetitively provided along a longitudinal direction of the gate line (GL), and the same kind of the color filters (CF) may be repetitively provided along a longitudinal direction of the data line (DL).

The black matrix (BM) is formed along the interfaces of the color filters (CF), thereby defining the plurality of color filters (CF), and optically separating the adjacent color filters (CF) from one another.

The overcoat layer122with a predetermined thickness is formed on an entire rear surface of the upper substrate120including the plurality of color filters (CF) and black matrix (BM), to thereby planarize the rear surface of the upper substrate120facing toward the lower substrate120. An alignment film (not shown) for aligning the liquid crystal layer130may be formed on the overcoat layer122.

The display panel100may further comprise a lower polarizing plate114and an upper polarizing plate124.

The lower polarizing plate114is adhered to the rear surface of the lower substrate110, that is, the surface facing toward a backlight unit (not shown), whereby the light emitted from the backlight unit and being incident on the lower substrate110is polarized by the lower polarizing plate114.

The upper polarizing plate124is formed on a front surface of the upper substrate120, that is, the surface which is not in contact with the liquid crystal layer130, thereby polarizing the light transmitting through the upper substrate120.

For the stereoscopic image mode, the left-eye image of the stereoscopic image is displayed on the left-eye displaying area (LDA) of the display panel100, and the right-eye image of the stereoscopic image is displayed on the right-eye displaying area (RDA) of the display panel100.

The light-guiding member200is formed on the upper substrate120while being overlapped with the interface between the left-eye displaying area (LDA) and the right-eye displaying area (RDA), whereby the light-guiding member200reflects the light incident at a predetermined angle. The light-guiding member200reflects the light which is transmitted at a predetermined angle via the left-eye displaying area (LDA) and is advanced toward the upper side of the right-eye displaying area (RDA), whereby the reflected light is advanced toward the upper side of the left-eye displaying area (LDA). Also, the light-guiding member200reflects the light which is transmitted at a predetermined angle via the right-eye displaying area (RDA) and is advanced toward the upper side of the left-eye displaying area (LDA), whereby the reflected light is advanced toward the upper side of the right-eye displaying area (RDA).

Also, the light-guiding member200collects the light passing through the left-eye displaying area (LDA) and the right-eye displaying area (RDA), to thereby improve the luminance of the stereoscopic image.

As shown in (a) ofFIG. 3, the light-guiding member200according to the first embodiment of the present invention is hollowly formed from the upper surface of the upper substrate120, wherein the light-guiding member200has a triangular-shaped or V-shaped cross section. Preferably, a depth (d) of the light-guiding member200is more than a half of an entire thickness of the upper substrate120. Preferably, a width (W) of the light-guiding member200may be the same as or larger than a width of the black matrix (BM), but not necessarily. For optimizing efficiency of the device, the depth and width of the light-guiding member200may be appropriately changed based on the size and structure of the display panel100.

As shown in (b) ofFIG. 3, the light-guiding member200according to the second embodiment of the present invention is hollowly formed from the upper surface of the upper substrate120, wherein the light-guiding member200has a square-shaped cross section. Preferably, a depth (d) of the light-guiding member200is more than a half of an entire thickness of the upper substrate120. Preferably, a width (W) of the light-guiding member200may be the same as or larger than a width of the black matrix (BM), but not necessarily. For optimizing efficiency of the device, the depth and width of the light-guiding member200may be appropriately changed based on the size and structure of the display panel100.

As shown in (c) ofFIG. 3, the light-guiding member200according to the third embodiment of the present invention is hollowly formed from the upper surface of the upper substrate120, wherein the light-guiding member200has a rectangle-shaped cross section. Preferably, a depth (d) of the light-guiding member200is more than a half of an entire thickness of the upper substrate120. Preferably, a width (W) of the light-guiding member200may be smaller than a width of the black matrix (BM).

The light-guiding member200may be hollowly formed from the surface of the upper substrate120by a physical etching process or chemical etching process using a mask (not shown). At this time, the physical etching process may be a sand-blasting process; and the chemical etching process may be a dry-etching process or wet-etching process. A process for forming the light-guiding member200is carried out before a process for adhering the upper polarizing plate124after a process for bonding the lower substrate110and the upper substrate120to each other.

InFIGS. 1 and 2, the optical-axis changing member300divides the light incident via the left-eye displaying area (LDA) and right-eye displaying area (RDA) defined in the display panel100into the left-eye image and right-eye image having the different optical axes. For this, the optical-axis changing member300may comprise a base member310, a left-eye retarder320L, a right-eye retarder320R, and a reflection preventing film330.

The base member310may be formed of glass or film with a predetermined thickness.

The left-eye retarder320L is formed on a rear surface of the base member310while being corresponding to the left-eye displaying area (LDA) defined in the display panel100. The left-eye retarder320L is positioned on the upper polarizing plate124. The left-eye retarder320L changes the optical axis of the light which is incident via the left-eye displaying area (LDA), whereby the left-eye image of the stereoscopic image is provided to the viewer's left eye for the stereoscopic image mode. At this time, the left-eye retarder320L may change the light incident via the left-eye displaying area (LDA) to the left-handed polarized light.

The right-eye retarder320R is formed on the rear surface of the base member310while being corresponding to the right-eye displaying area (RDA) defined in the display panel100and being in parallel to the left-eye retarder320L. At this time, the right-eye retarder320R is formed between each of the left-eye retarders320L, and is positioned on the upper polarizing plate124. The right-eye retarder320R changes the optical axis of the light which is incident via the right-eye displaying area (RDA), whereby the right-eye image of the stereoscopic image is provided to the viewer's right eye for the stereoscopic image mode. At this time, the right-eye retarder320R may change the light incident via the right-eye displaying area (RDA) to the right-handed polarized light.

The reflection preventing film330may be adhered to or coated onto the front surface of the base member310, thereby decreasing the surface reflection, and removing the light interference or scattering by the reflected light.

The aforementioned optical-axis changing member300may be adhered to the front surface of the upper polarizing plate124by an adhesive material (not shown).

As shown inFIG. 4, in case of the stereoscopic image display device according to the first embodiment of the present invention, the light-guiding member200reflects the right-eye image (RI), which is transmitted via the right-eye displaying area (RDA) and is then advanced toward the adjacent left-eye retarder320L, toward the right-eye retarder320R; and simultaneously reflects the left-eye image (LI), which is transmitted via the left-eye displaying area (LDA) and is then advanced toward the adjacent right-eye retarder320R, toward the left-eye retarder320L.

In the stereoscopic image display device according to the first embodiment of the present invention, the light-guiding member200is formed on the upper substrate120while being overlapped with the interface between the left-eye displaying area (LDA) and the right-eye displaying area (RDA), thereby improving picture quality by preventing crosstalk in the left-eye image and right-eye image of the stereoscopic image, and realizing the wide vertical (up-and-down) viewing angle of the stereoscopic image. Generally, the vertical viewing angle of the stereoscopic image is generally determined by an interval between the rear surface of the upper substrate120and the retarders320L and320R, and the width of the black matrix (BM), which is typically about 30°. Meanwhile, the vertical viewing angle of the stereoscopic image according to the present invention is determined by the width of the black matrix (BM), and an interval (D) between the rear surface of the upper substrate120and the light-guiding member200by the light collection of the light-guiding member200. Accordingly, the vertical viewing angle of the stereoscopic image according to the present invention may be increased depending on the depth (d) of the light-guiding member200, which might be above 60°.

FIG. 5is a cross section view illustrating a stereoscopic image display device according to the second embodiment of the present invention, which is a cross section view along A-A′ ofFIG. 1.

Referring toFIG. 5, the stereoscopic image display device according to the second embodiment of the present invention comprises a display panel100, a light-guiding member200, an optical-axis changing member300, and a light reflecting layer400. Except a structure of the light reflecting layer400, the stereoscopic image display device according to the second embodiment of the present invention is identical in structure to the stereoscopic image display device according to the first embodiment of the present invention, whereby a detailed explanation for the same parts100,200, and300will be omitted, and a same reference numbers will be used throughout the drawings to refer to the same or like parts.

The light reflecting layer400is formed inside the light-guiding member200which is hollowly formed from an upper surface of an upper substrate120, wherein the light-guiding member200has a triangular-shaped or quadrangle-shaped cross section. Preferably, the light reflecting layer400is formed of a material with high reflectance, for example, aluminum or silicon. The light reflecting layer400reflects the light transmitting through the light-guiding member200toward the targeted retarder320L or320R, whereby the picture quality and luminance of the stereoscopic image can be improved owing to the high reflection efficiency in the light-guiding member200.

FIGS. 6A to 6Dillustrate a method for manufacturing the stereoscopic image display device according to the embodiment of the present invention.

A method for manufacturing the stereoscopic image display device according to the embodiment of the present invention will be described with reference toFIGS. 6A to 6D.

First, as shown inFIG. 6A, the display panel100is prepared, wherein the display panel100comprises the lower substrate110and the upper substrate120which are bonded to each other, and are provided with the left-eye displaying area (LDA) for displaying the left-eye image of stereoscopic image, and the right-eye displaying area (RDA) for displaying the right-eye image of stereoscopic image. On the lower substrate110, there is the thin film transistor array112which includes the plurality of gate lines (not shown), the plurality of data lines (not shown), and the plurality of pixels (not shown). On the rear surface of the upper substrate120, there is a color filter array which includes the plurality of color filters (CF) corresponding to the respective pixels of pixel regions defined by the black matrix (BM); and the overcoat layer formed flat at a predetermined thickness to cover the black matrix (BM) and the plurality of color filters (CF). The lower substrate110and the upper substrate120are bonded to each other with the liquid crystal layer130interposed therebetween.

Then, as shown inFIG. 6B, the light-guiding member200is formed in the upper substrate120, and more particularly, along the interface between the left-eye displaying area (LDA) and the right-eye displaying area (RDA). At this time, as shown in (a) to (c) ofFIG. 3, the light-guiding member200is hollowly formed from the upper surface of the upper substrate120, wherein the light-guiding member200has the triangular-shaped or quadrangle-shaped cross section. At this time, the light-guiding member200is hollowly formed in such a manner that the depth (d) of the light-guiding member200is more than a half of an entire thickness of the upper substrate120. The light-guiding member200may be hollowly formed from the surface of the upper substrate120by the physical etching process or chemical etching process using the mask (not shown). At this time, the physical etching process may be the sand-blasting process; and the chemical etching process may be the dry-etching process or wet-etching process.

As shown inFIG. 6C, the lower polarizing plate114is adhered to the rear surface of the lower substrate110; and the upper polarizing plate124is adhered to the front surface of the upper substrate120with the light-guiding member200formed therein.

As shown inFIG. 6D, the optical-axis changing member300is provided on the upper substrate120. At this time, the optical-axis changing member300may comprise the base member310, the left-eye retarder320L, the right-eye retarder320R, and the reflection preventing film330.

The base member310may be formed of glass or film with the predetermined thickness.

The left-eye retarder320L is formed on the rear surface of the base member310while being corresponding to the left-eye displaying area (LDA). The left-eye retarder320L changes the optical axis of the light which is incident via the left-eye displaying area (LDA), that is, makes the leftward polarization, whereby the left-eye image of the stereoscopic image is provided to the viewer's left eye for the stereoscopic image mode.

The right-eye retarder320R is formed between each of the left-eye retarders320L to be corresponding to the right-eye displaying area (RDA) while being in parallel with the left-eye retarder320L. The right-eye retarder320R changes the optical axis of the light which is incident via the right-eye displaying area (RDA), that is, makes the rightward polarization, whereby the right-eye image of the stereoscopic image is provided to the viewer's right eye for the stereoscopic image mode.

The reflection preventing film330may be adhered to or coated onto the front surface of the base member310, thereby decreasing the surface reflection, and removing the light interference or scattering by the reflected light.

The aforementioned optical-axis changing member300may be adhered to the front surface of the upper polarizing plate124by the adhesive material (not shown).

For the manufacturing method of the stereoscopic image display device according to the embodiment of the present invention, as shown inFIG. 7, the process for forming the light-guiding member200in the upper substrate120may further comprise forming the light reflecting layer400inside the light-guiding member200.

The light reflecting layer400is formed inside the light-guiding member200which is hollowly formed from the upper surface of the upper substrate120, wherein the light-guiding member200has the triangular-shaped or quadrangle-shaped cross section. Preferably, the light reflecting layer400is formed of the material with high reflectance, for example, aluminum or silicon. The light reflecting layer400reflects the light transmitting through the light-guiding member200toward the targeted retarder320L or320R, whereby the picture quality and luminance of the stereoscopic image can be improved owing to the high reflection efficiency in the light-guiding member200.

For the manufacturing method of the stereoscopic image display device according to the embodiment of the present invention, as shown inFIG. 8, the aforementioned upper polarizing plate124is adhered to the front surface of the upper substrate120with the light-guiding member200and the light reflecting layer400formed therein.

For the above explanation of the stereoscopic image display device according to the embodiment of the present invention and the method for manufacturing the same, the light-guiding member200is formed in the upper substrate120of the liquid crystal display panel100, but not necessarily. However, the light-guiding member200may be formed in an upper substrate of another flat-type display panel instead of the liquid crystal display panel100.

The stereoscopic image display device according to the embodiment of the present invention may be used for a mobile communication terminal, a notebook computer, a monitor, a television, a public display, and etc.

In the above stereoscopic image display device according to the present invention, the light-guiding member200is formed in the upper substrate120while being overlapped with the interface between the left-eye displaying area (LDA) and the right-eye displaying area (RDA).

This enables to improve the picture quality by preventing the crosstalk of the left-eye image and right-eye image of the stereoscopic image through the light reflection of the light-guiding member200.

Also, it is possible to realize the wide vertical (up-and-down) viewing angle and good luminance of the stereoscopic image through the light collection of the light-guiding member200.