Liquid crystal display apparatus

A liquid crystal display apparatus is provided. The liquid crystal display apparatus according to an exemplary embodiment of the present disclosure includes: a backlight; a liquid crystal display panel; and a light collecting layer. The liquid crystal display panel includes a first scan line and a second scan line crossing the first scan line. The light collecting layer is configured to collect lights from the backlight and guide the lights toward the liquid crystal display panel. Further, the light collecting layer includes: a first light collecting sheet having a plurality of light collecting structures extended in a first direction; and a second light collecting sheet disposed on the first light collecting sheet and having a plurality of light collecting structures extended in a second direction orthogonal to the first direction. Herein, the first direction is inclined with respect to an extension direction of the scan line.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the priority of Korean Patent Application No. 10-2014-0130925 filed on Sep. 30, 2014, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.

BACKGROUND

Field

The present disclosure relates to a liquid crystal display apparatus, and more particularly, to a liquid crystal display apparatus including a light collecting layer capable of minimizing a moire phenomenon of the liquid crystal display apparatus.

Description of the Related Art

A liquid crystal display apparatus refers to a display apparatus including a liquid crystal display panel in which a liquid crystal layer is provided. The liquid crystal display apparatus is driven by adjusting a transmittance of the liquid crystal display panel with respect to light from a light source such as a backlight unit. In recent years, demand for a liquid crystal display apparatus with a higher resolution has increased.

A light collecting layer including a prism structure is disposed between the liquid crystal display panel and the backlight unit. The light collecting layer is configured to increase a utilization efficiency ratio between light transmitted toward the liquid crystal display panel and light emitted from the backlight unit. The light collecting layer includes a plurality of light collecting structures in order to collect the light emitted from the backlight in a direction toward the liquid crystal display panel. The plurality of light collecting structures has a mountain shape or a triangular shape in a cross-sectional view. Light from the backlight is refracted on a surface of the light collecting structure in a direction toward the liquid crystal display panel. Thus, more light from the backlight unit proceeds to the liquid crystal display panel, so that the utilization efficiency of the light emitted from the backlight unit is increased. As the utilization efficiency of the lights from the backlight unit is increased, the luminance of the liquid crystal display apparatus may be increased.

However, in a liquid crystal display apparatus using a light collecting layer in order to increase the utilization efficiency of light, cyclically repeated light collecting structures of the light collecting layer and cyclically repeated pixel structures of the liquid crystal display panel may be overlapped. Thus, a moire phenomenon that causes a stripe-shaped bright/dark spot pattern may be generated. Since the moire phenomenon deteriorates the quality of a liquid crystal display apparatus, various methods have been studied in order to solve such a problem.

For example, a method has been studied in which a distance between the cyclically repeated light collecting structures of the light collecting layer is set to be smaller than a distance between sub-pixels. Thus, stripes caused by a moire phenomenon cannot be recognized with the naked eye. Further, a method has been studied in which a light collecting structure is configured as a combination of curved shapes, so that the light collecting structures cannot be cyclically repeated.

However, as a liquid crystal display panel is required to have a higher resolution, the method in which a distance between light collecting structures is set to be smaller than a distance between sub-pixels became not efficient in terms of cost and process since it requires manufacture of light collecting structures with small separation distances. Further, when a light collecting structure is configured as a combination of curved shapes, it is difficult to maximize the utilization efficiency of light and a localized moire phenomenon may be caused by a pattern of curved shapes.

SUMMARY

When a pixel pattern of a liquid crystal display panel and a pattern of a light collecting structure are completely identical to each other in angle, a moire phenomenon should not be generated. However, the inventors of the present disclosure recognized that even if a pixel pattern of a liquid crystal display panel and a pattern of a light collecting structure are designed to be completely identical with each other in angle, the pixel pattern and the pattern of the light collecting structure may not be completely identical with each other in angle due to a process error. After the pixel pattern and the pattern of the light collecting structure are designed to be completely identical with each other in angle, if the two patterns are different from each other in angle due to a process error, a moire phenomenon is generated. Further, a distance between stripes caused by the moire phenomenon is increased, so that the moire stripes can be easily recognized with the naked eye.

Further, the inventors of the present disclosure recognized that since a liquid crystal display panel is designed to have a high resolution, a moire phenomenon can be more easily observed even with a minute process error.

Accordingly, the inventors of the present disclosure invented a new liquid crystal display apparatus capable of minimizing a moire phenomenon by designing a pattern of a light collecting structure to be different from a pixel pattern of a liquid crystal display panel.

Accordingly, an objective of the present disclosure is to provide a liquid crystal display apparatus having a new structure capable of minimizing a moire phenomenon of the liquid crystal display apparatus while maximizing the utilization efficiency of light from a light source.

Further, another objective of the present disclosure is to provide a liquid crystal display apparatus having a structure in which a moire phenomenon cannot be recognized even when a liquid crystal display panel is designed to have a high resolution and a process error is generated.

The objects of the present disclosure are not limited to the aforementioned objects, and other objects, which are not mentioned above, will be apparent to a person having ordinary skill in the art from the following description.

According to an aspect of the present disclosure, a liquid crystal display apparatus is provided including: a backlight; a liquid crystal display panel; and a light collecting layer. The liquid crystal display panel includes pixels defined by a plurality of lines crossing each other. The light collecting layer is configured to collect light from the backlight in a direction toward the liquid crystal display panel and includes a prism mountain aligned in a grid array. Further, an angle between an extension direction of the prism mountain aligned in a grid array and an extension direction of each of the plurality of lines is determined to be an angle at which a moire phenomenon caused by a repeated pattern of the pixels is not recognized. With the above-described configuration of the liquid crystal display apparatus according to an exemplary embodiment of the present disclosure, a cycle of a repeated moire stripe is reduced, so that moire stripes cannot be distinguished with the naked eye. Therefore, in the liquid crystal display apparatus according to an exemplary embodiment of the present disclosure, a moire phenomenon may not be recognized.

According to another feature of the present disclosure, the light collecting layer includes a plurality of light collecting sheets. Further, an extension direction of a prism mountain of one of the plurality of light collecting sheets is perpendicular to an extension direction of a prism mountain of another one of the plurality of light collecting sheets.

According to yet another feature of the present disclosure, the extension direction of the prism mountain aligned in a grid array is inclined with respect to the extension direction of each of the plurality of lines.

According to still another feature of the present disclosure, the plurality of lines includes a scan line and a data line that define a pixel. Also, an angle between an extension direction of the scan line and the extension direction of the prism mountain aligned in a grid array and an angle between an extension direction of the data line and the extension direction of the prism mountain aligned in a grid array are in the range of 4 to 12 degrees or 94 to 102 degrees.

According to another aspect of the present disclosure, there is provided a liquid crystal display apparatus including: a backlight; a liquid crystal display panel; and a light collecting layer. The liquid crystal display panel includes a scan line and a scan line crossing the scan line. The light collecting layer is configured to refract the light from the backlight in a direction toward the liquid crystal display panel. Further, the light collecting layer includes: a first light collecting sheet having a plurality of light collecting structures extended in a first direction; and a second light collecting sheet on the first light collecting sheet and having a plurality of light collecting structures extended in a second direction orthogonal to the first direction. Herein, the first direction is inclined with respect to an extension direction of the scan line.

According to another feature of the present disclosure, an angle between the first direction and the extension direction of the scan line is in the range of 4 to 12 degrees or 94 to 102 degrees.

According to yet another feature of the present disclosure, the second direction is inclined with respect to an extension direction of the data line.

According to still another feature of the present disclosure, the extension direction of the data line is inclined with respect to the extension direction of the scan line.

According to still another feature of the present disclosure, an angle between the second direction and the extension direction of the data line is in the range of 4 to 12 degrees or 94 to 102 degrees.

According to still another feature of the present disclosure, the plurality of light collecting structures of the first light collecting sheet and the plurality of light collecting structures of the second light collecting sheet are orthogonal to each other.

According to still another feature of the present disclosure, the plurality of light collecting structures has a triangular prism structure in a cross-sectional view.

According to still another feature of the present disclosure, the light collecting layer further includes a scattering layer between the first light collecting sheet and the second light collecting sheet.

According to still another feature of the present disclosure, the light collecting layer further includes a scattering layer on the first light collecting sheet or under the second light collecting sheet.

According to still another feature of the present disclosure, the scattering layer includes a plurality of scattering particles.

According to still another feature of the present disclosure, the scattering layer of the light collecting layer is configured to have a haze of 90% or more in the light collecting layer.

According to yet another aspect of the present disclosure, a liquid crystal display apparatus is provided including: a liquid crystal display panel including a plurality of lines and pixels; and a light collecting layer configured to collect lights from a backlight in a direction toward the liquid crystal display panel and including a prism mountain aligned in a grid array. Herein, the prism mountain has a shape extended in a direction in which a pixel array is not matched to a grid array.

According to another feature of the present disclosure, the prism mountain aligned in a grid array is extended in a direction inclined with respect to an extension direction of the plurality of lines. Thus, interference between the pixel array and the grid array is reduced.

According to yet another feature of the present disclosure, the light collecting layer includes a plurality of light collecting sheets. Further, grid arrays of a plurality of prism mountains included in the plurality of light collecting sheets are orthogonal to each other.

According to still another feature of the present disclosure, the light collecting layer further includes a scattering layer so as to further reduce interference between the pixel array and the grid array by relieving a regular grid array of the prism mountains.

Details of other exemplary embodiments will be included in the detailed description of the disclosure and the accompanying drawings.

According to the present disclosure, due to a new structure of a liquid crystal display apparatus, a distance between moire stripes is reduced so as not to be recognized with the naked eye. Thus, the quality of the liquid crystal display apparatus is improved.

Further, according to the present disclosure, a pixel pattern of a liquid crystal display panel and a pattern of a light scattering structure of a light scattering layer are disposed so as not to be matched to each other. Thus, generation of a recognizable moire stripe is suppressed which may be caused by a process error when the two patterns are disposed to be matched to each other.

The effects of the present disclosure are not limited to the aforementioned effects, and other various effects are included in the present specification.

DETAILED DESCRIPTION

Advantages and features of the present disclosure, and methods for accomplishing the same will be more clearly understood from exemplary embodiments described below with reference to the accompanying drawings. However, the present disclosure is not limited to the following exemplary embodiments but may be implemented in various different forms. The exemplary embodiments are provided only to complete disclosure of the present disclosure and to fully provide a person having ordinary skill in the art to which the present disclosure pertains with the category of the disclosure, and the present disclosure will be defined by the appended claims.

The shapes, sizes, ratios, angles, numbers, and the like shown in the accompanying drawings for describing the exemplary embodiments of the present disclosure are merely examples, and the present disclosure is not limited thereto. Like reference numerals generally denote like elements throughout the present specification. Further, in the following description, a detailed explanation of known related technologies may be omitted to avoid unnecessarily obscuring the subject matter of the present disclosure. The terms such as “including,” “having,” and “consist of” used herein are generally intended to allow other components to be added unless the terms are used with the term “only”. Any references to singular may include plural unless expressly stated otherwise.

When an element or layer is referred to as being “on” another element or layer, it may be directly on the other element or layer, or intervening elements or layers may be present.

Throughout the whole specification, the same reference numerals denote the same elements.

Since size and thickness of each component illustrated in the drawings are represented for convenience in explanation, the present disclosure is not necessarily limited to the illustrated size and thickness of each component.

The features of various embodiments of the present disclosure can be partially or entirely bonded to or combined with each other and can be interlocked and operated in technically various ways as can be fully understood by a person having ordinary skill in the art, and the embodiments can be carried out independently of or in association with each other.

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

FIG. 1is a schematic cross-sectional view of a liquid crystal display apparatus according to embodiment of the present disclosure. Referring toFIG. 1, a liquid crystal display apparatus100includes a liquid crystal display panel140, a transparent plate130, a first chassis120, a second chassis110, a backlight180, a light guide plate150, a reflective plate160, and a light collecting layer170.

Referring toFIG. 1, the liquid crystal display panel140is a display panel configured to adjust an amount of transmitted light L from the backlight180by aligning a liquid crystal and allowing the transmitted light L to pass through a color filter so as to realize a color. Although not illustrated in the drawing, the liquid crystal display panel140includes a plurality of transistors, lines for supplying various signals and a voltage to the plurality of transistors, and a liquid crystal layer.

The transparent plate130bonded to a top side of the liquid crystal display panel140is disposed on the liquid crystal display panel140. The transparent plate130is bonded to the liquid crystal display panel140. The transparent plate130may be formed of a flexible material such as glass or polyimide. However, the liquid crystal display apparatus100according to an exemplary embodiment of the present disclosure is not limited to the liquid crystal display apparatus100in which the liquid crystal display panel140is bonded to the transparent plate130as illustrated inFIG. 1. However, it may be the liquid crystal display apparatus100including a cover part configured to fix a liquid crystal display panel by fixing a part of the liquid crystal display panel140. The liquid crystal display apparatus100including a cover part is formed such that the liquid crystal display panel140is exposed to the outside. The liquid crystal display panel140has a resolution of, for example, 200 ppi, or UHD (ultra high definition) or more. If the liquid crystal display panel140has a high resolution, a pixel pattern of the liquid crystal display panel140becomes gradually miniaturized. Therefore, it becomes more difficult to match an angle of the miniaturized pixel pattern to an angle of a light collecting pattern of the light collecting layer170, and the mismatched pixel pattern and light collecting pattern may cause a moire phenomenon. In the liquid crystal display apparatus100according to an exemplary embodiment of the present disclosure, even if the high-resolution liquid crystal display panel140is employed, a moire pattern caused by a moire phenomenon cannot be recognized with the naked eye.

The first chassis120is disposed outside the liquid crystal display panel140. The first chassis120protects the liquid crystal display apparatus100by suppressing the introduction of foreign substances from a lateral side of the liquid crystal display apparatus100. The first chassis120may be formed of, for example, a plastic material in order to suppress a short circuit with the other components. The second chassis110is disposed under the first chassis120. The second chassis110reduces the introduction of foreign substances from a bottom side of the liquid crystal display apparatus100and protects the liquid crystal display apparatus100against a shock or the like. The second chassis110is configured to be extended toward the first chassis120such that the backlight180can be disposed on an inner lateral side of the second chassis110.

The first chassis120and the second chassis110are not limited to the structure as illustrated inFIG. 1, but may have a structure configured to support various components depending on a design. For example, a top side or a bottom side of the second chassis110may be protruded in part depending on a design. Further, if the second chassis110is formed of metal, a part of the second chassis110may be insulated in order to suppress an electrical connection with the other components.

The backlight180is operated as a light at a lateral side of the liquid crystal display apparatus100and under the liquid crystal display panel140. The backlight180may include a light source such as an LED (light emitting diode).

The light guide plate150is disposed on a lateral side of the backlight180. The light guide plate150is a component configured to guide the light L in order for the light L from the backlight180to be uniformly irradiated in a direction in which the liquid crystal display panel140is disposed. The light L from the backlight180is incident into the light guide plate150and then is uniformly irradiated toward the liquid crystal display panel140based on a light emitting structure such as a surface light collecting structure within the light guide plate150.

The reflective plate160is disposed under the light guide plate150. The reflective plate160reflects light toward the liquid crystal display panel140. The reflected light passes through the light guide plate150from the backlight180. The reflective plate160is a plate formed of a metal having a high reflectivity or an alloy of various metals.

The light collecting layer170configured to transmit the light L from the light guide plate150is disposed on the light guide plate150. The light collecting layer170may be composed of optical layers configured to perform various optical functions and disposed on the light guide plate150. The light collecting layer170enables a light passing through the light guide plate150from the backlight180to be concentrated toward the liquid crystal display panel140. Therefore, more light L from the light guide plate150passes through the light collecting layer170and then proceeds toward the liquid crystal display panel140. Thus, the overall luminance of the liquid crystal display apparatus100is increased. Although not illustrated inFIG. 1, a scattering layer configured to scatter the light L may be disposed on the light guide plate150.

The light collecting layer170includes two light collecting sheets. The light collecting layer170including two light collecting sheets will be described in more detail with reference toFIG. 2.

FIG. 2is a schematic exploded perspective view of a liquid crystal display apparatus according to an exemplary embodiment of the present disclosure. For convenience in explanation,FIG. 2illustrates only the liquid crystal display panel140and the light collecting layer170including a first light collecting sheet172and a second light collecting sheet174among various components of the liquid crystal display apparatus100illustrated inFIG. 1.

The first light collecting sheet172and the second light collecting sheet174include a plurality of light collecting structures172aand174a, respectively. Each of the light collecting structures172aand174aof the first light collecting sheet172and the second light collecting sheet174function as a prism. In order to do so, the light collecting structures172aand174aare formed cyclically on the first light collecting sheet172and the second light collecting174, respectively. Each of the plurality of light collecting structures172aof the first light collecting sheet172is extended in a first direction, and the light collecting structures172aare formed to be parallel with each other. Each of the plurality of light collecting structures174aof the second light collecting sheet174is extended in a second direction orthogonal to the first direction. Further, the light collecting structures174aare formed to be parallel with each other.

To be more specific, the light collecting structures172aand174aof the first light collecting sheet172and the second light collecting sheet174are formed into an inverted V-shape. That is, the light collecting structures172aand174aof the first light collecting sheet172and the second light collecting sheet174have a triangular prism shape or a prism mountain in a cross-sectional view. Further, top lines172band174bof the inverted V-shapes and bottom lines of the V-shaped grooves are formed to be alternately disposed. Further, the top lines172bof the light collecting structures172aof the first light collecting sheet172are orthogonal to the top lines174bof the of the light collecting structures174aof the second light collecting sheet174. Likewise, the bottom lines of the light collecting structures172aof the first light collecting sheet172are orthogonal to the bottom lines of the light collecting structures174aof the second light collecting sheet174. The top lines172band the bottom lines of the light collecting structures172aof the first light collecting sheet172are parallel with an extension direction of the light collecting structures172a. Also, the top lines174band the bottom lines of the light collecting structures174aof the second light collecting sheet174are parallel with an extension direction of the light collecting structures174a.

Lights incident into the first light collecting sheet172and the second light collecting sheet174from various directions are refracted on surfaces of the light collecting structures172aand174ain a direction toward the liquid crystal display panel140. Since the extension direction of the light collecting structures172aof the first light collecting sheet172is orthogonal to the extension direction of the light collecting structures174aof the second light collecting sheet174, the light L incident in a direction inclined with respect to the first direction and the second direction can be refracted in a direction toward the liquid crystal display panel140. Therefore, the light collecting layer170includes the first light collecting sheet172. Further, the second light collecting sheet174enables most of the light L having non-uniform incident angles with respect to the light collecting layer170to proceed toward the liquid crystal display panel140.

The light collecting structures172aof the first light collecting sheet172extended in the first direction of the liquid crystal display apparatus100according to an exemplary embodiment of the present disclosure are disposed to be inclined with respect to a long side of the liquid crystal display panel140. Referring toFIG. 2, the extension direction of the light collecting structures172aof the first light collecting sheet172is neither parallel with nor orthogonal to the long side of the liquid crystal display panel140. However, it is inclined with respect to the long side the liquid crystal display panel140. Further, the extension direction of the light collecting structures174aof the second light collecting sheet174is orthogonal to the extension direction of the light collecting structures172aof the first light collecting sheet172. Thus, the extension direction of the light collecting structures174aof the second light collecting sheet174is inclined with respect to the long side of the liquid crystal display panel140in the same manner. In other words, the prism mountain of the first light collecting sheet172or the second light collecting sheet174may have a shape extended in a direction in which a pixel array is not matched to a grid array. Further, the prism mountains of the light collecting sheets172and174aligned in a grid array are extended in a direction inclined with respect to an extension direction of the plurality of lines so as to reduce interference between the pixel array and the grid array.

Further, the long side of the liquid crystal display panel140may be parallel with one of the lines of the liquid crystal display panel140. Thus, an extension direction of a light collecting structure may be inclined with respect to the long side of the liquid crystal display panel140, which means that an extension direction of a light collecting structure may be inclined with respect to one of the lines of the liquid crystal display panel140. The extension direction of the lines of the liquid crystal display panel140and the extension directions of the light collecting structures172aand174aof the first light collecting sheet172and the second light collecting sheet174will be described later with reference toFIG. 3.

FIG. 3is a schematic three-dimensional top view provided to explain a relationship between a liquid crystal display panel and a light collecting layer in a liquid crystal display apparatus according to an exemplary embodiment of the present disclosure.FIG. 3illustrates a sub-pixel region PXL1of the liquid crystal display panel140illustrated inFIG. 2and the top lines172band174bof the light collecting structures172aand174aof the first light collecting sheet172and the second light collecting sheet174on one plane. For convenience in explanation, illustration of the other components is omitted.

Referring to a part of the liquid crystal display apparatus100enlarged inFIG. 3, the sub-pixel region PXL1of the liquid crystal display panel may be defined by a scan line SL and a data line DL shown in dotted line. The scan line SL is extended in a horizontal direction. The data line DL is extended in a vertical direction and has a “<” shape inclined to the left at a central portion. To be specific, the data lines DL are inclined and extended from the facing scan lines SL at a corresponding angle. For example, the data line DL may be inclined at 80 to 89 degrees with respect to the scan line SL. Therefore, the data line DL may have a hexagonal shape partially inclined to the left at the center of the sub-pixel region PXL1.

InFIG. 3, the top lines172bindicating the extension direction of the light collecting structures of the first light collecting sheet are shown in alternate long and short dash line. Further, the top lines174bindicating the extension direction of the light collecting structures of the second light collecting sheet are shown in solid line. The top lines172bof the first light collecting sheet are inclined as much as θ1with respect to the scan line SL. θ1as an angle between the first direction as the extension direction of the light collecting structures of the first light collecting sheet and the extension direction of the scan line SL is in the range of between 4 degrees and 49 degrees. If θ1is less than 4 degrees, a cycle of a moire stripe caused by the light collecting structures of the first light collecting sheet and sub-pixel patterns is increased, so that moire stripes can be recognized with the naked eye. If θ1is 49 degrees or more, an angle between the top line172and the data line DL is decreased, so that moire stripes can be recognized with the naked eye. Preferably, θ1may be in the range of between 4 degrees and 12 degrees. Even if θ1is in between 12 degrees and 49 degrees, moire stripes may not be recognized. However, if θ1is more than 12 degrees, the area of a light collecting sheet to be discarded at the time of manufacturing the light collecting sheet is increased. Therefore, if θ1is more than 12 degrees, the cost efficiency may be reduced.

A cycle of a moire stripe is determined by the following Equation 1.

Herein, P is a cycle of a moire stripe, p is a cycle of an overlapped line pattern, and θ is an angle between lines of two patterns. For convenience in explanation, it is assumed that the cycle of an overlapped line pattern is constant. According to Equation 1, as θ is closer to 0, P is increased, and as θ is increased, P is decreased. It is known that when P is 50 μm or more, a moire pattern can be recognized with the naked eye. When P is less than 50 μm, even if a moire pattern is generated, a pattern having a cycle of less than 50 μm cannot be recognized with the naked eye. Even if the cycle p is determined depending on a process or other factors, it is possible to minimize recognition of a moire pattern with the naked eye by adjusting θ and lowering P to a predetermined level or less.

FIG. 4AtoFIG. 4Bare schematic diagrams provided to explain a change in cycle of a moire stripe. Referring toFIG. 4Afirst,FIG. 4Aillustrates that two line patterns are overlapped. The two line patterns are inclined as much as θa, and each of the two patterns has lines disposed with the cycle p. Since the two line patterns are disposed to be inclined, a new pattern of moire stripes is generated having a cycle of P1. Although the cycle p of a pattern is illustrated as being constant for convenience in explanation, the cycle p can be set in various ways depending on a design of a pixel pattern and a light collecting pattern. Further, a cycle of the pixel pattern may not be identical with a cycle of the light collecting pattern.

Meanwhile, referring toFIG. 4B,FIG. 4Billustrates that two line patterns are inclined as much as θb greater than θa, and each of the two patterns has lines disposed with the cycle p in the same manner as shown inFIG. 4a. Likewise, since the two line patterns are disposed to be inclined, a new pattern is generated. The new pattern has a cycle of P2. The cycle P2is shorter than the cycle P1, and if the cycle P2becomes short enough, the new pattern may not be recognized with the naked eye.

That is, referring toFIG. 4aandFIG. 4b, if the cycle p is constant, the cycle patterns P1and P2of the moire stripes, generated when the two line patterns are overlapped, are determined by the angles θa and θb between the patterns, respectively. Further, if moire stripes have a long cycle, the moire stripes can be recognized with the naked eye. On the other hand, if moire stripes have a sufficiently short cycle, the moire stripes cannot be recognized with the naked eye. That is, an angle between an extension direction of a prism mountain aligned in a grid array and an extension direction of each of the plurality of lines is determined as an angle at which a moire phenomenon caused by a repeated pattern of pixels is not recognized.

Therefore, in the liquid crystal display apparatus100according to an exemplary embodiment of the present disclosure, an angle between the lines that define the sub-pixel and the extension directions of the light collecting structures of the first light collecting sheet and the second light collecting sheet is set to be 4 degrees or more. Thus, a cycle of moire stripes is reduced so as not to be recognized with the naked eye.

If a pattern of a light collecting structure of a light collecting sheet is designed to be matched to a pixel pattern in the same manner as the prior art, moire stripes having a considerably long cycle P may be generated due to a minute angle error during a process. If moire stripes having such a long cycle are recognized with the naked eye, the quality of an image displayed on the liquid crystal display apparatus100deteriorates.

However, in the liquid crystal display apparatus100according to an exemplary embodiment of the present disclosure, even if a minute angle error is generated during a process, an angle between the lines that define the sub-pixel and the extension directions of the light collecting structures of the first light collecting sheet and the second light collecting sheet is high enough. Therefore, there is no significant change in a cycle of moire stripes, and the cycle is short enough. Thus, the moire stripes are not recognizable by the naked eye.

Hereinafter, referring toFIG. 3again, an angle relationship between the top lines172band174bof the first light collecting sheet and the second light collecting sheet, respectively, and the other components will be described. In the liquid crystal display apparatus100, moire stripes may be generated not only by the light collecting structures of the first light collecting sheet and the scan lines SL, but also by other lines and the first light collecting sheet or the second light collecting sheet. Therefore, it is possible to sufficiently reduce a moire phenomenon by setting the angle θ1between the top line172bof the first light collecting sheet and the scan line SL to at least 4 degrees. Also, it is possible to minimize a moire phenomenon by adjusting an angle between the other components.

In the liquid crystal display apparatus100according to an exemplary embodiment of the present disclosure, an angle between various components is determined such that moire stripes cannot be recognized. Referring toFIG. 3, the angle between the top line174bof the second light collecting sheet and the data line DL, i.e., the angle θ2between the second direction of the light collecting structure of the second light collecting sheet and the extension direction of the data line DL, may be in the range of 4 degrees or more and 49 degrees or less. The data line DL is not orthogonal to the scan line SL, but is inclined with respect to the scan line SL. However, in the liquid crystal display apparatus100, the top line172bof the first light collecting sheet may be orthogonal to the top line174bof the second light collecting sheet in order to maximize refraction of light from the light collecting layer toward the liquid crystal display panel.

Further, an angle θ3between the top line174bof the second light collecting sheet and the data line DL may be between 4 degrees and 49 degrees. The data line DL is not extended straight, but is bent at a point. Therefore, when an angle between the top line174bof the second light collecting sheet and the data line DL is determined, a bending direction of the data line DL is also taken into consideration.

The following Table 1 shows how much moire stripes are recognized when an extension direction of light collecting structures of a light collecting layer in the liquid crystal display apparatus100is inclined with respect to an extension direction of lines of the liquid crystal display panel. The first light collecting sheet and the second light collecting sheet in the light collecting layer were inclined at angles as shown in Table 1 with respect to the liquid crystal display panel illustrated inFIG. 3, and levels of recognition of moire stripes were measured. Further, an angle was indicated with reference to the angle between the top line172bof the first light collecting sheet and the scan line SL. A level of recognition of moire stripes was indicated as 0 when no moire stripe was recognized and a level of recognition of moire stripes when the angle between the top line172bof the first light collecting sheet and the scan line SL is 0 degrees was indicated as 10.

Referring to Table 1, when the angle between the top line172bof the first light collecting sheet and the scan line SL is 0 degree, the most moire stripes are recognized. The most moire stripes are recognized at the 0-degree angle because moire stripes having a long cycle are generated due to a process error as described above.

, Recognition of moire stripes is remarkably decreased even if the angle is 4 degrees. The reason for such a decrease may be because that a cycle of a moire stripe is decreased due to an increased angle between the top line172bof the first light collecting sheet and the scan line SL. Thus, a moire strip cannot be recognized with the naked eye. However, the reason why a moire stripe is still recognized may be because of a moire stripe caused by the light collecting structure of the second light collecting sheet and the data line DL.

If the angle is 8 degrees or more, moire stripes are substantially not recognized. The moire stripes caused by the light collecting structure of the first light collecting sheet and the scan line SL already have an unrecognizable cycle. Further, since the angle between the light collecting structure of the second light collecting sheet and the data line DL is increased, a cycle of a moire stripe caused by them is decreased. Therefore, the moire stripe caused by the light collecting structure of the second light collecting sheet and the data line DL may not be recognized with the naked eye.

If the moire stripes caused by the light collecting structures of the first light collecting sheet and the second light collecting sheet and the lines have a sufficiently short cycle and thus cannot be recognized with the naked eye, the angle may be 12 degrees or more. For example, θ1, θ2, or θ3may be in the range of 94 degrees to 139 degrees, 221 degrees to 266 degrees (−94 degrees to −139 degrees), or 311 degrees to 356 degrees (−4 degrees to −49 degrees).

In the liquid crystal display apparatus100according to an exemplary embodiment of the present disclosure, as illustrated inFIG. 2andFIG. 3, the light collecting structures of the first light collecting sheet and the second light collecting sheet are inclined with respect to the lines, so that moire stripes caused by them are not recognizable. Thus, the quality of images displayed on the liquid crystal display apparatus100can be improved. Further, the convex-concave structures of the first light collecting sheet and the second light collecting sheet maintain a vertical relationship, so that a light collecting effect can be maintained.

FIG. 5is a schematic three-dimensional top view provided to explain a relationship between a liquid crystal display panel and a light collecting layer in a liquid crystal display apparatus according to another exemplary embodiment of the present disclosure. In the same manner as illustrated inFIG. 3,FIG. 5illustrates a sub-pixel region PXL2of a liquid crystal display panel240and top lines272band274bof light collecting structures of a first light collecting sheet and a second light collecting sheet on one plane. The other components are substantially the same as illustrated in the cross-sectional view ofFIG. 3. Therefore, redundant description thereof will be omitted. InFIG. 5, the top lines272bindicating an extension direction of the light collecting structures of the first light collecting sheet are shown in solid line and the top lines274bindicating an extension direction of the light collecting structures of the second light collecting sheet are shown in alternate long and short dash line.

InFIG. 5, the liquid crystal display panel240of a liquid crystal display apparatus200has a rectangular shape. The liquid crystal display panel240has upper and lower long sides240aand right and left short sides240b. An angle between an extension direction of the long side240aof the liquid crystal display panel240and an extension direction of the light collecting structure of the first light collecting sheet is an acute angle. Therefore, a cycle of a moire stripe between a pattern of the light collecting structure and a pattern of sub-pixels parallel with the long sides240aof the liquid crystal display apparatus200is decreased. Thus, moire stripes cannot be recognized with the naked eye.

Further, the liquid crystal display panel240has the sub-pixel region PXL2formed into a rectangular shape. The rectangular sub-pixel region PXL2is defined by the scan line SL and the data line DL. An extension direction of the scan line SL is parallel with the extension direction of the long side240aof the liquid crystal display panel240. InFIG. 5, the data line DL does not have a bent (“<”) shape, but has a shape parallel with a line orthogonal to the scan line SL. An extension direction of the data line DL is parallel with an extension direction of the short side240bof the liquid crystal display panel240.

An angle between the extension direction of the long side240aof the liquid crystal display apparatus200and the extension direction of the light collecting structure of the first light collecting sheet is determined to be an angle at which a moire stripe is not recognized in the liquid crystal display apparatus200. For example, the top line272bas a line along the extension direction of the light collecting structure of the first light collecting sheet is inclined as much as θ4with respect to the scan line SL. θ4may be in the range of 4 degrees to 86 degrees. Even when the sub-pixel region PXL2has a rectangular shape, θ4may be increased in order to decrease a cycle of moire stripes. If the cycle of moire stripes is sufficiently decreased, moire stripes may not be recognized with the naked eye.

An angle between the extension direction of the light collecting structure of the first light collecting sheet and the extension direction of the line may be limited depending on the extension direction of the line in the liquid crystal display panel240. For example, if the scan line SL is formed into a zigzag shape, the extension direction of the light collecting structures of the first light collecting sheet and the second light collecting sheet may be determined to have an angle of 4 degrees or more with respect to any extension direction of the scan line SL.

In the liquid crystal display apparatus200according to another exemplary embodiment of the present disclosure, even if the sub-patterns have various patterns as illustrated inFIG. 5, the light collecting structures of the first light collecting sheet and the second light collecting sheet are disposed to be inclined with respect to a pattern of the sub-pixels. Thus, it is possible to minimize a moire pattern recognized due to the sub-pixels and the light collecting structures.

FIG. 6is a schematic cross-sectional view provided to explain a light collecting layer of a liquid crystal display apparatus according to yet another exemplary embodiment of the present disclosure. Referring toFIG. 6, a light collecting layer of a liquid crystal display apparatus300includes the first light collecting sheet172, the second light collecting sheet174, a first scattering layer380, and a second scattering layer390. The other components are substantially the same as illustrated inFIG. 1andFIG. 2. Therefore, a redundant description thereof will be omitted.

The first scattering layer380is disposed under the second light collecting sheet174, and the second scattering layer390is disposed between the first light collecting sheet172and the second light collecting sheet174. The first scattering layer380and the second scattering layer390include a plurality of scattering particles382and392. The plurality of scattering particles382and392are fixed to the upper light collecting sheets by adhesive layers384and394.

If a light from a light guide plate is incident into the plurality of scattering particles382and392, the light is refracted in various random directions toward the liquid crystal display panel. Therefore, a light is incident into the liquid crystal display panel not only from a direction perpendicular to the liquid crystal display panel but also from various directions. Therefore, a pattern caused by the light collecting structures of the first light collecting sheet172and the second light collecting sheet174is more dimly seen. Since the pattern of the light collecting structures is dimly seen, moire stripes generated when a pattern caused by the lines of the liquid crystal display panel and the pattern of the light collecting structures are overlapped may be less easily recognized. The first scattering layer380and the second scattering layer390may be configured to have a haze of 90% or more in the light collecting layer. The first scattering layer380and the second scattering layer390may include a high concentration of the scattering particles382and392in order to have a haze of 90% or more.

The following Table 2 shows a level of moire stripes caused by an extension direction of the light collecting structures. Further, an extension direction of lines when a light scattering layer is included or not included in a light collecting layer. Levels of recognition of moire stripes of the liquid crystal display apparatus300without a scattering layer were measured under the same condition as given in Table 1. Further, levels of recognition of moire stripes of the liquid crystal display apparatus300including a scattering layer were measured under the same condition except that the scattering layer is included.

The levels of recognition of moire stripes depending on a degree were similar regardless of whether the scattering layer is included or not. However, when the scattering layer is included, the level of recognition of moire stripes of the liquid crystal display apparatus300is further decreased by 1.

FIG. 6illustrates that the scattering particles382and392of the first scattering layer380and the second scattering layer390are randomly dispersed. However, the scattering particles382and392may be disposed to be concentrated on a specific portion of the light collecting structures of the first light collecting sheet172and the second light collecting sheet174—for example, on a top portion of a prism shape. If the scattering particles382and392are disposed in such a way as to be concentrated on the top portion of the prism shape, it is possible to secure an value sufficient to lower a level of recognition of moire stripes even with fewer scattering particles382and392.

AlthoughFIG. 6illustrates that the light collecting layer includes both the first scattering layer380and the second scattering layer390, the light collecting layer may include only one of the first scattering layer380and the second scattering layer390. In the liquid crystal display apparatus300according to yet another exemplary embodiment of the present disclosure, if the light collecting layer has a sufficient haze and moire stripes of the liquid crystal display apparatus300are less recognized, only one scattering layer may be used.

In the liquid crystal display apparatus300according to yet another exemplary embodiment of the present disclosure, as illustrated inFIG. 6, the light collecting layer further includes the scattering layers380and390. Thus, a regular grid array of the light collecting structures of the first light collecting sheet172and the second light collecting sheet174can be relieved. Therefore, interference between the pixel array and the grid array can be further reduced. Further, the light collecting structures of the first light collecting sheet172and the second light collecting sheet174are dimly seen, so that a level of recognition of moire stripes can be lowered. Thus, the quality of an image displayed on the liquid crystal display apparatus300can be improved.